ARTICLE | doi:10.20944/preprints201802.0115.v1
Subject: Social Sciences, Education Studies Keywords: sustainability; Green Engineering; curriculum development; chemical education; engineering education
Online: 17 February 2018 (13:23:39 CET)
The purpose of this study was to develop e-learning activities that integrated sustainability concepts and practices in process engineering education. Two blended courses were developed with two activities evaluated quantitatively and qualitatively to measure student engagement, quality of responses, and incorporation of sustainability in their arguments. Social network analysis and lexical analysis were used to assess students’ participation in discussions and peer reviews. In the online discussion, 97 comments were made averaging 120 words per comment. The participants averaged 3.88 comments, with the majority of comments exhibiting simple and complex argumentation, a deep reflection, and widespread use of terms associated with sustainability such as recycling, pollution, waste, and environment. Furthermore, evaluation of peer reviews revealed that the participants demonstrated they could identify errors and positives in an argument. Therefore, this study demonstrated that e-learning, particularly peer review and online discussion could help chemistry and engineering students understand sustainability.
CONCEPT PAPER | doi:10.20944/preprints202104.0281.v1
Online: 12 April 2021 (11:59:07 CEST)
In our long-term engineering practice, we have found that it is often not enough to use only engineering knowledge to solve the practical problems in the engineering. Therefore, we believe that in the education of engineering students, we should not only pay attention to the teaching of engineering knowledge, but also pay attention to the application of knowledge of Humanities in the engineering, for the students. In this two-part concept paper, we put forward the concept of a new discipline, that is, Engineering & Humanities, which we will carry forward in future. And this concept paper serves just as a guide to the Tossing out a brick to get a jade gem with the implications for the development of the engineering education.
REVIEW | doi:10.20944/preprints202001.0282.v1
Subject: Engineering, Control & Systems Engineering Keywords: Systems Engineering; Complex networks; Multiagent systems; Optimisation; Processes Systems Engineering
Online: 24 January 2020 (14:27:32 CET)
Systems Engineering is an ubiquitous discipline of Engineering overlapping industrial, chemical, mechanical, manufacturing, control, software, electrical, and civil engineering. It provides tools for dealing with the complexity and dynamics related to the optimisation of physical, natural, and virtual systems management. This paper presents a review of how multi-agent systems and complex networks theory are brought together to address Systems Engineering and management problems. The review also encompasses current and future research directions both for theoretical fundamentals and applications in Industry. This is made by considering trends such as mesoscale, multiscale, and multilayer networks; along with the state-of-art analysis on network dynamics and intelligent networks. Critical and smart infrastructure, manufacturing processes, and supply chain networks are instances of research topics for which this literature review is highly relevant.
ARTICLE | doi:10.20944/preprints202107.0697.v2
Subject: Social Sciences, Education Studies Keywords: Engineering education; Engineering-centered PjBL; Power generation systems; Sustainable energy; Sustainability
Online: 24 August 2021 (16:35:23 CEST)
(1) Background: Due to the high proportion of disadvantaged students in a rural school in Taiwan and the gap between students’ concepts and practices of environmental protection and sustainable energy, four science and mathematics teachers in this school planned an engineering-centered PjBL of sustainable energy curriculum in a Makers Club to enhance students’ creativity, engineering skills, practices of environmental protection and sustainable energy, and learning attitudes; (2) Methods: This study is four-year action research. Teachers and students initiated the idea from rebuilding an old fan in a classroom; (3) Results: The students in the Makers Club improved their engineering skills and created various green-power generation devices (evolved from ventilation ball generator, hydropower, ocean current power generators to tiny, 3D-printing wind power generators). They turned environmental protection and sustainable energy concepts into actions during practices and won awards from science and engineering fairs every year. This creative and supportive atmosphere spread from the club to the whole school and improved the students’ practices of environmental protection and learning attitudes after long-term implementation; (4) Conclusions: The design principles of the engineering-centered PjBL of sustainable energy curriculum played a critical role and were outlined at the end of the study.
REVIEW | doi:10.20944/preprints202010.0620.v1
Online: 29 October 2020 (14:50:51 CET)
Bioprinting is a relatively new yet evolving technique predominantly used in regenerative medicine and tissue engineering. 3D bioprinting techniques combine the advantages of creating Extracellular Matrix (ECM) like environments for cells and computer-aided tailoring of predetermined tissue shapes and structures. The essential application of bioprinting is for the regeneration or restoration of damaged and injured tissues by producing implantable tissues and organs. The capability of bioprinting is yet to be fully scrutinized in sectors like the patient-specific spatial distribution of cells, bio-robotics, etc. In this review, currently developed experimental systems and strategies for the bioprinting of different types of tissues as well as for drug delivery and cancer research are explored for potential applications. This review also digs into the most recent opportunities and future possibilities for the efficient implementation of bioprinting to restructure medical and technological practices.
REVIEW | doi:10.20944/preprints201608.0036.v1
Online: 4 August 2016 (11:00:19 CEST)
Disease, trauma, and aging account for a significant number of clinical disorders. Regenerative medicine is emerging as a very promising therapeutic option. The design and development of new cell-customized biomaterials able to mimic ECM functionalities represent one of the major strategy to control the cell fate and stimulate tissue regeneration. Recently, hydrogels have received a considerable interest for their use in the modulation and control of cell fate during regeneration processes. Several synthetic bioresponsive hydrogels are being developed in order to facilitate cell-matrix and cell-cell interactions. In this review new strategies and future perspectives of such synthetic cell microenvironment will be highlighted.
REVIEW | doi:10.20944/preprints202203.0305.v1
Online: 23 March 2022 (03:12:40 CET)
Cardiovascular diseases are the leading cause of death worldwide. Cardiovascular diseases complication can give rise to myocardial infarction which produces cell death by blockage of blood flow, leading to loss of heart function. Current treatments directed at heart repair have several disadvantages such as the lack of donors for heart transplantation or the use of non-bioactive inert materials for replacement of the damage tissue. New treatment strategies involve stimulation of heart tissue regeneration with the use of bioactive materials like chitosan, in combination with cells and biochemical factors. Chitosan scaffolds have the necessary proprieties of biocompatibility, porosity, and biodegradation, that imitates the heart extracellular matrix. Chitosan scaffolds physical proprieties, such as electrical conductivity and mechanical proprieties, can be improved by different preparation techniques and by the functionalization with other materials.
ARTICLE | doi:10.20944/preprints201707.0065.v1
Subject: Engineering, Biomedical & Chemical Engineering Keywords: Biomedical Engineering, Cell Stretching, Mechanobiology.
Online: 24 July 2017 (10:04:57 CEST)
Cellular response to mechanical stimuli is an integral part of cell homeostasis. The interaction of the extracellular matrix with the mechanical stress plays an important role in cytoskeleton organisation and cell alignment. Insights from the response can be utilised to develop cell culture methods that achieve predefined cell patterns, which are critical for tissue remodelling and cell therapy. We report the working principle, design, simulation and characterisation of a novel electromagnetic cell stretching platform based on the double-sided axial stretching approach. The device is capable of introducing a cyclic and static strain pattern on a cell culture. The platform was tested with fibroblasts. The experimental results are consistent with the previously reported cytoskeleton reorganisation and cell reorientation induced by strain. The orientation of the cells is highly influenced by external mechanical cues. Cells reorganise their cytoskeleton to avoid external strain and to maintain intact extracellular matrix arrangements.
REVIEW | doi:10.20944/preprints202209.0132.v1
Subject: Medicine & Pharmacology, Obstetrics & Gynaecology Keywords: tissue engineering; ovary; uterus; vagina; gynecology
Online: 9 September 2022 (07:33:27 CEST)
Female gynecological organ dysfunction can cause infertility and psychological distress, decreasing quality of life of affected women. Incidence is constantly increasing due to growing rates of cancer and delaying of childbearing age in the developed world. Current treatments are often unable to restore organ function, and occasionally are the cause for female infertility. Alternative treatment options are currently being developed in order to face the inadequacy of current practices. In this review, pathologies and current treatments of gynecological organs (ovaries, uterus, and vagina) will be described. The state-of-the-art of tissue engineering alternatives to common practices are evaluated with a focus on in vivo models. Tissue engineering is an ever-expanding field, integrating various domains of modern science to create sophisticated tissue substitutes in the hopes of repairing or replacing dysfunctional organs using autologous cells. Application to gynecology has the potential of restoring female fertility and sexual wellbeing.
REVIEW | doi:10.20944/preprints202011.0697.v1
Subject: Life Sciences, Biochemistry Keywords: tissue engineering,; biocompatible materials; skeletal muscle
Online: 27 November 2020 (15:02:14 CET)
Tissue engineering, also called “regenerative medicine”, refers to attempt to create functional human tissue from cells in laboratory. This is a field that uses living cells, biocompatible materials, suitable biochemical and physical factors and their combinations, to create tissue-like structures.. To date, no tissue engineered skeletal muscle implants have been developed for clinical use, but it may represent a valid alternative to treat volumetric muscle loss in the near future. Herein, we reviewed the literature and showed different techniques to produce synthetic tissues with the same architectural, structural and functional properties of native tissues.
ARTICLE | doi:10.20944/preprints201811.0486.v1
Subject: Mathematics & Computer Science, General & Theoretical Computer Science Keywords: Software-Defined Networking (SDN), Traffic Engineering
Online: 20 November 2018 (08:24:28 CET)
The digital society is an outcome of the Internet which has nearly made everything connected and accessible no matter where or when. Nevertheless, despite the fact that conventional IP networks are complicated and very hard to manage, they are still widely adopted. The already established policies make the network configuration/reconfiguration a complex process that reacts to errors, load, and modifications. The prevailing networks are vertically integrated which makes things more and more complicated: Data planes and control are strapped together. Software-defined networking is a model that is meant to solve this issue by splitting the vertical integration and detaching the network’s control logic from the implicit routers and switches; this could be achieved by reinforcing centralization of network control and making the network programmable. In this work, we worked to implement MPLS networks with SDN, to enhance the traffic engineering over the network, and to minimize the network delay and latency, with minimum cost using three of the different SDN networks. The experiment results showed the advantage of the proposed approach for reducing the network delay, comparing with previous studies. Where the average of network delay in our approach reaches to 3.01 milliseconds.
REVIEW | doi:10.20944/preprints201609.0091.v1
Subject: Life Sciences, Biotechnology Keywords: biomaterial; scaffold; protein; keratin; tissue engineering
Online: 26 September 2016 (10:25:01 CEST)
In tissue engineering scaffolds take the place of the natural extra cellular matrix (ECM). The natural ECM is the extracellular part of animal tissue that usually provides structural support to the animal cells in addition to performing various other important functions. The design aspect along with the choice of the material for the artificial scaffold is very crucial to cell differentiation, adhesion, proliferation, and the transport of the growth factors or other bio molecular signals. In addition to the material and design of the scaffolds, it is necessary to replicate the normal physiological situation if the scaffold has to function as an implant. The cells have to be located in the porous scaffold to form a three dimensional assembly. The article discusses the important factors to be considered while designing a scaffold for tissue engineering and regenerative medicine.
ARTICLE | doi:10.20944/preprints202209.0019.v1
Subject: Biology, Other Keywords: enzyme-constrained model; Corynebacterium glutamicum; metabolic engineering
Online: 1 September 2022 (09:54:55 CEST)
Genome-scale metabolic model (GEM) is a powerful tool for interpreting and predicting cellular phenotypes under various environmental and genetic perturbations. However, GEM only consid-ers stoichiometric constraints, and the simulated growth and product yield values will show a monotonic linear increase with increasing substrate uptake rate, which deviates from the experi-mentally measured values. Recently, the integration of enzymatic constraints into stoichiometry-based GEMs was proven to be effective in making novel discoveries and predicting new engineer-ing targets. Here we present the first genome-scale enzyme-constrained model (eciCW773) for Corynebacterium glutamicum reconstructed by integrating enzyme kinetic data from various sources using ECMpy workflow based on the high-quality GEM of C. glutamicum (obtained by modifying the iCW773 model). The enzyme-constrained model improved the prediction of pheno-types and simulated overflow metabolism, while also recapitulating the trade-off between biomass yield and enzyme usage efficiency. Finally, we used eciCW773 to identify several gene modifica-tion targets for L-lysine production, most of which agree with previously reported genes. This study shows that incorporating enzyme kinetic information into the GEM enhances the cellular phenotypes prediction of C. glutamicum, which can help identify key enzymes and thus provide reliable guidance for metabolic engineering.
ARTICLE | doi:10.20944/preprints202207.0243.v1
Subject: Engineering, Industrial & Manufacturing Engineering Keywords: MTS; MTO; logistics strategy; advanced industrial engineering
Online: 18 July 2022 (03:25:16 CEST)
Strategic management sets the direction of a company for several years ahead. Managers and business owners who create strategy must anticipate and have the ability to see systemically—the paper deals with creating a logistics strategy for a company operating in the industrial sector. The first section summarises the theoretical background for strategy and logistics and current trends affecting logistics processes. The second chapter analyses the current state of the art in logistics strategy development and summarizes its problem areas. The central part of the paper is the proposal of a methodology for logistics strategy development in the industrial area by a progressive approach. The methodology is divided into 5 phases - preparatory, analytical, formulation, implementation, and evaluation and control phases. The methodology is partially validated. The created variants of the logistics strategy include the introduction of such elements that will lead to the gradual development of the Industry 4.0 trend in the given company. This is mainly the first variant called "automation," which includes the introduction of an automatic tractor for material import, the introduction of an automatic system for transport and storage of work in progress, and the introduction of a new logistics information system that will make greater use of already established barcodes (transparency, data in real-time).
ARTICLE | doi:10.20944/preprints202111.0024.v1
Subject: Mathematics & Computer Science, Analysis Keywords: Fake news detection; Deep learning; Feature Engineering
Online: 1 November 2021 (15:34:46 CET)
The rapid infiltration of fake news is a flaw to the otherwise valuable internet, a virtually global network that allows for the simultaneous exchange of information. While a common, and normally effective, approach to such classification tasks is designing a deep learning-based model, the subjectivity behind the writing and production of misleading news invalidates this technique. Deep learning models are unexplainable in nature, making the contextualization of results impossible because it lacks explicit features used in traditional machine learning. This paper emphasizes the need for feature engineering to effectively address this problem: containing the spread of fake news at the source, not after it has become globally prevalent. Insights from extracted features were used to manipulate the text, which was then tested on deep learning models. The original unknown yet substantial impact that the original features had on deep learning models was successfully depicted in this study.
ARTICLE | doi:10.20944/preprints201907.0142.v3
Subject: Medicine & Pharmacology, Allergology Keywords: glaucoma; tissue engineering; trabecular meshwork; outflow facility
Online: 8 December 2020 (10:09:17 CET)
Glaucoma is a blinding disease largely caused by increased resistance to drainage of fluid from the eye’s anterior chamber, resulting in elevated intraocular pressure (IOP). A major site of fluid outflow regulation and pathology is the trabecular meshwork (TM) at the entrance of the eye’s drainage system. We aimed to characterize the structural and functional properties of a newly developed tissue-engineered anterior segment eye culture model. We hypothesized that repopulation of a decellularized TM with non-native TM cells could restore aspects of normal TM. The decellularization protocol removed all cells and debris while preserving the ECM. Seeded cells localized to the TM region and progressively infiltrated the meshwork ECM. Cells reached a distribution comparable to control TM after four days of perfusion culture. After a perfusion rate increase challenge, tissue-engineered cultures reestablished normal IOPs (reseeded = 13.7±0.4 mmHg, decellularized = 35.2±2.2 mmHg, p < 0.0001). eGFP expressing CrFK control cells caused a high and unstable IOP (27.0±6.2 mmHg). In conclusion, we describe a readily available, storable, and biocompatible scaffold for anterior segment perfusion culture of non-native cells. Tissue-engineered organs demonstrated similarities to native tissues and may reduce the need for scarce donor globes in outflow research.
ARTICLE | doi:10.20944/preprints202011.0725.v1
Subject: Engineering, Automotive Engineering Keywords: Communications engineering; impulsive noise; variational Bayesian inference
Online: 30 November 2020 (12:02:13 CET)
Impulsive noise is the main limiting factor for transmission over channels affected by electromagnetic interference. We study the estimation of (correlated) Gaussian signals in an impulsive noise scenarios. In this work, we analyze some of the existing as well as some novel estimation algorithms. Their performance is compared, for the first time, for different channel conditions, including the Markov-Middleton scenario, where the impulsive noise switches between different noise states. Following a modern approach in digital communications, the receiver design is based on a factor graph model and implements a message passing algorithm. The correlation among signal samples as well as among noise states brings about a loopy factor graph, where an iterative message passing scheme should be employed. As it is well known, approximate variational inference techniques are necessary in these cases. We propose and analyze different algorithms and provide a complete performance comparison among them, showing that both Expectation Propagation, Transparent Propagation, and the Parallel Iterative Schedule approaches reach a performance close to the optimal, at different channel conditions.
ARTICLE | doi:10.20944/preprints202010.0446.v1
Online: 21 October 2020 (16:56:54 CEST)
The nature of fluid mechanics makes experimentation an important part of a course taught in the subject. Presented here is the application of a novel, large scale multidisciplinary model of practical education in a fluids engineering laboratory. Advantages of this approach include efficiencies through economy of scale leading to better pedagogy for students. The scale justifies dedicated academic resources to focus on developing laboratory classes and giving specific attention to designing activities that meet learning outcomes. Four examples of applying this approach to fluids mechanics experiments are discussed, illustrating tactics that have been developed and honed through many repeated instances of delivery. “The measurement lab” uses a flow measurement context to teach identifying and managing general experimental uncertainty. New students, unfamiliar with fluid mechanics are guided through a process to gain understanding that can be applied to all future experimental activities. The “pressure loss in pipes” lab discusses the advantage and process for sharing equipment and teaching resources between multiple cohorts. The provision for students is adapted for context, such as the degree program or year of study. The “weirs big and small” lab provides a methodology to teach the power of dimensional analysis to mechanical engineers using a field of fluid mechanics that is outside their usual theoretical studies. Finally, the “spillway design” lab discusses mechanisms to deliver student independent, open ended experiments at scale, without excessive staff resource requirement.
ARTICLE | doi:10.20944/preprints202009.0333.v1
Online: 15 September 2020 (06:13:10 CEST)
At the start of 2020 the rapid onset of the coronavirus pandemic forced higher education institutions across the world to pivot from face to face to remote teaching. For teaching methods that involve the transmission and dissemination of verbal/visual information between academic staff and students, video technologies provided immediate methods to respond to the restricted access to campus. Practical activities, that usually involve interaction with equipment, presented a greater challenge to adapt for remote delivery. With restrictions on higher education being partially lifted, many institutions worldwide intend to offer blended learning, prioritizing in-person activities that are troublesome to deliver online, such as practicals. Social distancing measures are reducing capacity and placing increased pressure on space, creating a need to optimise limited time students have in the lab and strategies to determine which activities can best utilize this limited resource. Time is constrained, leaving little opportunity to make radical changes to learning and teaching structures. In this publication, The department of Mulicdipalnary Engineering Education (MEE) at the University of Sheffield, utilise their experiences in practical teaching to provide simple, implementable ideas for blended practicals which maximize students’ learning and experiences within the envelope of available resources.
ARTICLE | doi:10.20944/preprints202006.0182.v1
Subject: Engineering, Other Keywords: practical engineering education; remote practicals; blended learning
Online: 14 June 2020 (15:29:04 CEST)
Multidisciplinary Engineering Education (MEE) at the University of Sheffield is dedicated to delivering, at scale, practical teaching to students in the Faculty of Engineering. The COVID-19 pandemic initiated the sudden suspension of face to face teaching required MEE to translate over 600 in-lab practicals to a remote delivery format. With little opportunity to coordinate, academic staff independently adopted a variety of tactics to ensure practical learning outcomes were maintained. Following the reactive response, a proactive reflection was conducted and six categories of tactics for remote practicals have been established. These categories are Provide digital artefacts; Simulated practicals; Synchronous remote participation; Asynchronous participation by proxy; Perform procedure in alternative environment; Remote staff support. The advantages and drawbacks of each of these categories is discussed and it is suggested which tactics are appropriate for particular learning outcomes or operational and environmental outcomes of equivalent in-lab practicals. Further work to comprehensively align outcomes to tactics is proposed and lasting benefit from the analysis can be realized by adopting a principle of Remote Enhanced Practicals.
Subject: Keywords: molecular engineering; natural conformation; polymeric biomaterials; biocompatibility
Online: 17 March 2020 (03:53:20 CET)
Molecular engineering research is the fundamental way and the only way for the development of biomaterials. Based on molecular engineering, the biocompatibility of natural conformation and polymer biomaterials was studied. In this paper, we discuss that natural conformation is the basis of protein biological function, and that the synergistic action of peptide chain and side group is the motive force for protein to construct natural conformation and complete biological function. On the basis of the influence of the adsorption of polymer biomaterials on the natural conformation of proteins, the relationship between biocompatibility of biomaterials and protein conformation is further explained. Studies have shown that bismuth molecular materials can only be applied in the market and have their functionality if they have good biocompatibility. Therefore, the biocompatibility evaluation of new materials has important practical significance.
ARTICLE | doi:10.20944/preprints201903.0031.v1
Subject: Keywords: Organ-on-Chip, tissue engineering, microfluidic technology
Online: 4 March 2019 (10:11:22 CET)
Organ-on-Chip is a game-changing technology born from the convergence of tissue engineering and microfluidic technology. Organ-on-Chip devices (OoCs) are expected to offer effective solutions to persisting problems in drug development and personalized disease treatments. This opinion paper surveys the current landscape in research, development, application and market opportunities for OoCs to help establishing a global and multi-stakeholder OoC ecosystem. Based on a bibliometric study, a market analysis, expert interviews, and panel discussions held at the ORCHID Vision Workshop (Stuttgart, 23 May 2018), we outline presently unmet needs, key challenges, barriers and perspectives of the field, and finally propose recommendations towards the definition of a comprehensive roadmap that could render OoCs realistic models of human (patho)physiology in the near future.
ARTICLE | doi:10.20944/preprints201811.0426.v1
Subject: Social Sciences, Other Keywords: sustainability; governance; piecemeal engineering; collaboration; Karl Popper
Online: 19 November 2018 (07:05:11 CET)
The challenges to sustainability governance across multiple geographical/cultural contexts lead us to the “piecemeal engineering” idea advocated by the philosopher Karl Popper, which explicitly considers context. We argue for adopting the piecemeal engineering approach, augmented by adaptive policies and modern (online) collaboration platforms to maximize the prospects of sustainable practices worldwide. This recommended course is not intended to be a theory in itself. Rather, it is a well-grounded, practical and practicable stop-gap measure in times when complexity and change outpace theories and strategies. We present a philosophical foundation for this “Augmented Popperian Experimentation.” Focusing on The Water Network (the largest collaborative platform for water researchers and professionals), we show that sustainability-oriented organizations in the water realm and others are inching toward the practice we advocate. We discuss implications.
ARTICLE | doi:10.20944/preprints202101.0574.v1
Subject: Engineering, Automotive Engineering Keywords: nanotechnologies; pavement engineering; scientific principles; material compatible design; mineralogy; safety, applicability and compatibility of new technologies; engineering principles
Online: 27 January 2021 (21:26:22 CET)
Good transportation systems are pre-requisites to economic development. Materials used for road construction are traditionally classified based of empirically developed archaic tests, often classifying naturally available materials as unsuitable for use in the load-bearing road pavement layers. Consequently, design standards usually require the use of imported materials at considerable costs, severely restricting road network development under scenarios of limited funding. New technologies and test methods based on sound engineering criteria, incorporating basic material sciences can substantially change this scenario. Nano-silane technologies can be utilised to improve naturally available materials to meet the engineering requirements of all layers in road structures. Material test and design methods have been developed and successfully tested in South Africa to build New-age Modified Emulsion (NME) stabilised layers in roads, meeting all engineering requirements. Accelerated Pavement Tests (APT) done on actual roads, proved the concept. This work is based on a scientific approach and identification of various factors that will impact on the successful application of applicable nanotechnology solutions. This paper aims to identify these fundamental factors that are a pre-requisite for the evaluation of nanotechnology solutions to ensure that new technologies are introduced into pavement engineering designs at a low risk to any implementing.
ARTICLE | doi:10.20944/preprints202207.0054.v1
Subject: Mathematics & Computer Science, Information Technology & Data Management Keywords: social engineering; security countermeasures; security awareness; security policies
Online: 5 July 2022 (03:39:36 CEST)
This research paper describes the social engineering concepts, techniques, and security countermeasures. This research aims to study various social engineering techniques to find the best countermeasures that would help to reduce social engineering attacks.
ARTICLE | doi:10.20944/preprints202205.0396.v1
Subject: Materials Science, Biomaterials Keywords: scaffold; collagen vitrigel; tissue engineering; cornea; corneal endothelium
Online: 30 May 2022 (11:25:19 CEST)
We set a feasible method to produce tailored collagen scaffolds and analyzed its potential for corneal engineering. Collagen-vitrigel membranes (CVM) were produced with a 1:1 ratio of Dulbecco’s Modified Eagle’s medium (DMEM), 1% antibiotics and 8% fetal bovine serum, and 5mg/mL collagen type I. Three volumes of collagen were used: 1X (2.8 L/mm2 of collagen), 2X, and 3X. Vitrification was done at 40% relative humidity (RH), 40° C, and 30 rpm using a matryoshka system set with a shaking-oven and a desiccator with a saturated K2CO3 solution. The CVM was characterized for width, microstructure, transparency, and biocompatibility using NIH3T3 cells. Surgical manipulation was assessed in an ex vivo corneal model. Constructs of corneal endothelial cells (CECs) and 2X-CVM were transplanted into five 18-month-old White New Zealand rabbits. CVM exhibited homogeneous surface and laminar organization. Membrane width increased with gel volume from 3.65µm to 7.2µm. 1X and 2X-CVM exhibited a 99% transmittance. NIH3T3 cells concentration increased 3-fold within 48 h with no significant difference among the 3 CVM (p = 0.323). The 2X-CVM was surgically manipulable. Transplantation of corneal endothelial cells (CECs) seeded over 2X-CVM restored corneal endothelium. The matrioshka system is a feasible method that yields CVM suitable for corneal engineering.
ARTICLE | doi:10.20944/preprints202205.0196.v1
Subject: Social Sciences, Education Studies Keywords: gamification methodology; teaching strategies; online teaching; chemical engineering
Online: 16 May 2022 (04:08:16 CEST)
As consequence of the digital transformation, e-learning methodologies have become an inseparable part of the standard classes in schools and universities, assuming an increasingly significant role in compensating for the difficulties resulting from the COVID-19 pandemic. Numerous pedagogical methodologies and strategies can be easily implemented in high education, promoting students’ motivation and interest in learning. This research study analyses the implementation of gamification pedagogical strategy on 50-60 undergraduate chemical engineering students at the university, by evaluating its effect on the success rate on a specific topic of Chemical Reactions Engineering subject and the motivation effect for the following topics. Our results show a significant positive effect of the gamification strategy on university lectures, increasing up to 25-30 % of the success ratio with an apparent motivation effect. During the subsequent years, the changes in the lifestyle of study also play a role in students’ performance. Therefore, it is necessary to evaluate case studies such as the one presented here to understand better the use of these pedagogical methods and strategies in high education, especially in technical subjects described in this paper.
REVIEW | doi:10.20944/preprints202111.0389.v1
Subject: Materials Science, Biomaterials Keywords: 3D Bioprinting; Extracellular Matrix; Extrusion; Biomaterials; Tissue Engineering
Online: 22 November 2021 (12:26:49 CET)
There is need to address the challenges of organ shortage, through development of tissues and organs with alternatives to those of the allograft-kind. This illustrates the quest behind novel biofabrication strategies such as 3D bio-printing, which is necessary to create artificial multi-cellular tissues/organs. Several findings have been reported in this review. First, the role of ECM components in tissue regenerative medicine is presented. Different ECM components such as collagen, gelatin, elastin, fibronectin, laminins and glycosaminoglycans are concisely examined for their tissue regenerative medicine applications. Next, current state of research on extrusion-based 3D bio-printing techniques and their limitations are reviewed. For example, we show that cell viability is still a challenge with extrusion, while the use of natural polymers such as collagen in improving composites’ mechanical properties is limited. Lastly, we examine unresolved research questions necessary to advance the present state of research in the field.
ARTICLE | doi:10.20944/preprints202108.0214.v1
Subject: Engineering, Civil Engineering Keywords: sea level rise; climate change; infrastructure; coastal engineering
Online: 10 August 2021 (08:47:00 CEST)
The national study analyzes sea level rise (SLR) impacts based on 36 different SLR and storm surge scenarios across 5.7 million geographic locations and 3 time periods. Taking an approach based on engineering design guidelines and current cost estimates, the study details projected cost impacts for states, counties, and cities. These impacts are presented from multiple perspectives including total cost, cost per-capita, and cost per-square mile. The purpose of the study is to identify specific locations where infrastructure is vulnerable to rising sea levels. The study finds that Sea Level Rise (SLR) and minimal storm surge is a $400 billion threat to the United States by 2040 that includes a need for at least 50,000 miles of protective barriers. The research is limited in its scope to protecting coastal infrastructure with sea walls. Additional methods exist and may be appropriate in individual situations. The study is original in that it is a national effort to identify infrastructure that is vulnerable as well as the cost associated with protecting this infrastructure.
ARTICLE | doi:10.20944/preprints202105.0161.v1
Subject: Life Sciences, Biochemistry Keywords: protein splicing; intein; crystal structure; hyperthermophile; protein engineering
Online: 10 May 2021 (10:29:29 CEST)
Inteins are prevalent among extremophiles. Mini-inteins with robust splicing properties are of particular interest for biotechnological applications due to their small size. However, biochemical and structural characterization has still been limited to a small number of inteins, and only a few inteins serve as widely used tools in protein engineering approaches. We determined the crystal structure of a naturally-occurring Pol-II mini-intein from Pyrococcus horikoshii and compared it with two other natural mini-inteins from Pyrococcus horikoshii. Despite the similar sizes, the comparison revealed distinct differences in insertions and deletions, implying specific evolutionary pathways from distinct ancestral origins. Our studies suggest that sporadically distributed mini-inteins might be more promising for further protein engineering applications than the highly conserved mini-inteins. Structural investigations of more inteins could guide the shortest path to finding novel robust mini-inteins suitable for protein engineering purposes.
ARTICLE | doi:10.20944/preprints202103.0388.v1
Subject: Materials Science, Biomaterials Keywords: Biomimetic hydrogels; hybrid nanocomposites; anomalous sorption; Tissue engineering
Online: 15 March 2021 (13:44:37 CET)
Innovative tissue engineering biomimetic hydrogels based on hydrophilic polymers have been investigated for their physical and mechanical properties. 5% to 25% by volume loading PHEMA-nanosilica glassy hybrid samples were equilibrated at 37°C in aqueous physiological isotonic and hypotonic saline solutions (0.15 and 0.05 M NaCl) simulating two limiting possible compositions of physiological extracellular fluids. The glassy and hydrated hybrid materials were characterized both for dynamo-mechanical properties and equilibrium absorptions in the two physiological-like aqueous solutions. Mechanical and the morphological modifications occurring in the samples have been described. The 5% volume nanosilica loading hybrid nanocomposite composition showed mechanical characteristics in the dry and hydrated states that were comparable to those of cortical bone and articular cartilage, respectively, and then chosen for further sorption kinetics characterization. Sorption and swelling kinetics were monitored up to equilibrium. Changes in water activities and osmotic pressures in the water-hybrid systems equilibrated at the two limiting solute molarities of the physiological solutions have been related to the observed anomalous sorption modes using the Flory-Huggins interaction parameter approach. The bulk modulus of the dry and glassy PHEMA-5% nanosilica hybrid at 37°C has been observed to be comparable with the values of the osmotic pressures generated from the sorption of isotonic and hypotonic solutions. The anomalous sorption modes and swelling rates are coherent with the difference between osmotic swelling pressures and hybrid glassy nano-composite bulk modulus: the lower the differences the higher the swelling rate and equilibrium solution uptakes. Bone tissue engineering benefits of use of tuneable biomimetic scaffold biomaterials that can be “designed” to act as biocompatible and biomechanically active hybrid interfaces are discussed.
ARTICLE | doi:10.20944/preprints202011.0583.v1
Subject: Life Sciences, Biochemistry Keywords: Itaconic acid; U. maydis; Metabolic engineering; Fungi; Yeast
Online: 23 November 2020 (13:47:27 CET)
Ustilago maydis, member of the Ustilaginaceae family, is a promising host for the production of several metabolites including itaconic acid. This dicarboxylate has great potential as a bio-based building block in the polymer industry, and is of special interest for pharmaceutical applications. Several itaconate overproducing Ustilago strains have been generated by metabolic and morphology engineering. This yielded stabilized unicellular morphology through fuz7 deletion, reduction of by-product formation through deletion of genes responsible for itaconate oxidation and (glyco)lipid production, and the overexpression of the regulator of the itaconate cluster ria1 and the mitochondrial tricarboxylate transporter encoded by mttA from Aspergillus terreus. In this study, itaconate production was further optimized by consolidating these different optimizations into one strain. The combined modifications resulted in itaconic acid production at theoretical maximal yield, which was achieved under biotechnologically relevant fed-batch fermentations with continuous feed.
REVIEW | doi:10.20944/preprints202011.0398.v1
Subject: Chemistry, Electrochemistry Keywords: bioelectrocatalysis; nanostructured electrodes; protein engineering; bioelectrosynthesis; photo-bioelectrocatalysis
Online: 16 November 2020 (08:32:45 CET)
Bioelectrocatalysis has become one of important research fields in electrochemistry and provided a firm base for an important technology for application to various bioelectrochemical devices such as biosensors, biofuel cells, and biosupercapacitors. The understanding and technology in bioelectrocatalysis have been greatly improved by introducing nanostructured electrode materials and protein-engineering methods over the last few decades. Recently, the electro-enzymatic production of renewable energy resources and useful organic compounds (bioelectrosynthesis) also attracts worldwide attention. In this review, we summarize recent progress in applications of enzymatic bioelectrocatalysis.
ARTICLE | doi:10.20944/preprints202005.0207.v2
Subject: Mathematics & Computer Science, Information Technology & Data Management Keywords: Software Development; Citizen Programming; JSON Schema; Data Engineering
Online: 28 May 2020 (03:04:35 CEST)
A novel software engineering platform called the Dynamic Nuchwezi Architecture Platform (DNAP) is introduced, specified and its novelties explained. The unique features of this platform are explained and several new concepts and abstractions upon which its implementation, usage, and analysis are hinged also elaborately discussed. The motivations for this new approach to building especially tools used in data engineering are spelled out and the platform is contrasted against other existing technologies of a similar kind. Finally, it is shown what known limitations DNAP suffers, as well as what room for further research and improvement there is in this field.
Subject: Social Sciences, Accounting Keywords: construction engineering; lean supply chain; target cost management
Online: 13 November 2019 (08:57:42 CET)
The lean supply chain of construction engineering projects is to achieve the maximum satisfaction of the owners' needs in order to effectively achieve the goal of supply chain management. This paper explores an effective method of lean supply chain cost management for construction engineering projects with target cost management, so that each participating unit on the supply chain node can fully utilizes its core competencies to minimize internal consumption and waste, and achieve the optimal overall efficiency of the supply chain. According to the requirements of the goal planning theory of the construction project company, establish a lean supply chain cost planning system for the construction project, realize the basic model of the lean supply chain cost management of the construction project, and set the target cost from the lean project of the construction project. The technical decomposition is established by the process of cost decomposition and cost pressure transmission and sub-target cost planning.
ARTICLE | doi:10.20944/preprints201807.0345.v1
Subject: Physical Sciences, Optics Keywords: spatial dispersion; field profile; metamaterials; photonics; RF engineering
Online: 19 July 2018 (05:23:37 CEST)
We show that an experimentally plausible system consisting of a modulated wire medium hosted in a metal cavity can preserve the longitudinal field profile shaping predicted by Boyd et al. (2018) on the basis of a perfectly periodic wire-only structure. These new frequency domain numerical results are a significant step towards justifying the construction of an experimental apparatus to test the field profile shaping in practise.
ARTICLE | doi:10.20944/preprints201806.0305.v1
Subject: Engineering, Civil Engineering Keywords: uncertainty; risk control; decision-making; tunnel engineering; entropy.
Online: 19 June 2018 (15:43:48 CEST)
Uncertainty is the main source of risk of geological hazards in tunnel engineering. Uncertainty information not only affects the accuracy of evaluation results, but also affects the reliability of decision-making schemes. Therefore, it is necessary to evaluate and control the impact of uncertainty on risk. In this study, the problems in existing entropy-hazard model such as inefficient decision-making and failure of decision-making are analysed, and an improved uncertainty evaluation and control process are proposed. Then the tolerance cost, the key factor in the decision-making model, is also discussed. It is considered that the amount of change in risk value (R1) can better reflect the psychological behaviour of decision-makers. Thirdly, common attribute decision models, such as the expected utility-entropy model, are analysed, and then the viewpoint of different types of decision-making issues that require different decision methods is proposed. The well-known Allais paradox is explained by the proposed methods. Finally, the engineering application results show that the uncertainty control idea proposed here is accurate and effective. This research indicates a direction for further research into uncertainty, and risk control, issues affecting underground engineering works.
REVIEW | doi:10.20944/preprints201803.0115.v1
Subject: Life Sciences, Cell & Developmental Biology Keywords: regenerative medicine; reprogramming; cardiac differentiation; secretoma; tissue engineering
Online: 15 March 2018 (05:02:41 CET)
Human induced pluripotent stem cells (hiPSCs) are reprogrammed cells that have hallmarks similar to embryonic stem cells including the capacity of self-renewal and differentiation into cardiac myocytes. The improvements in reprogramming and differentiating methods achieved in the past 10 years widened the use of hiPSCs, especially in cardiac research. hiPSC-derived cardiac myocytes (CMs) recapitulate phenotypic differences caused by genetic variations, making them human attractive disease models and useful tools for drug discovery and toxicology testing. In addition, hiPSCs can be used as source cells for cardiac regeneration in animal models. Here, we review the advances in the genetic and epigenetic control of cardiomyogenesis that underlies the significant improvement of the induced reprogramming of somatic cells to CMs. We also cover the phenotypic characteristics of the hiPSCs derived CMs, their ability to rescue injured CMs through paracrine effects, the novel approaches in tissue engineering for hiPSC-derived cardiac tissue generation, and finally, their potential use in biomedical applications.
ARTICLE | doi:10.20944/preprints201701.0137.v1
Subject: Engineering, Biomedical & Chemical Engineering Keywords: cell culture; bioreactor; live cell imaging; tissue engineering
Online: 31 January 2017 (12:39:46 CET)
Here, we present a staged approach for an innovative repurposing of a portable infant humidicrib into a live cell growth, observation, and imaging system. Furthmore, humidicrib can support different variations of “umbilical” bioreactors, and can be used to conduct electrophysiology experiments and in situ immunohistochemistry. Modifications incorporate a closed loop carbon dioxide (CO2) concentration control system with umbilical CO2 and heating support for tailored bioreactors. The repurposing cost is inexpensive and allows for the continued observation and imaging of cells. This prototype unit has been used to continuously observe and image live primary neurons for up to 21 days. This demonstrates the repurposed units’ suitability for use in tissue culture based research, particularly where modifications to microscopes are required or where sensitive manipulation outside of a standard incubator is needed.
REVIEW | doi:10.20944/preprints202109.0501.v2
Subject: Life Sciences, Immunology Keywords: Antigen Selection; Epitope Selection; Antibody Targeting; Epitope Accessibility; Antibody Engineering; Protein Engineering; Drug Targeting; Model-Informed Drug Discovery and Development
Online: 3 November 2021 (08:26:47 CET)
The target of an antibody plays a significant role in the success of antibody-based therapeutics and diagnostics, and to an extent, that of vaccine development. This importance is focussed on the target binding site – epitope, where epitope selection as a part of design thinking beyond traditional antigen selection using whole cell or whole protein immunisation can positively impact success. With purified recombinant protein production and peptide synthesis to display limited/selected epitopes, intrinsic factors that can affect the functioning of resulting antibodies can be more easily selected for. Many of these factors stem from the location of the epitope that can affect accessibility of the antibody to the epitope at a cellular or molecular level, direct inhibition of target antigen activity, conservation of function despite escape mutations, and even non-competitive inhibition sites. Through the incorporation of novel computational methods for predicting antigen changes to model-informed drug discovery and development, superior vaccines and antibody-based therapeutics or diagnostics can now be more easily designed to mitigate failures. With detailed examples, this review highlights the new opportunities, factors and methods of predicting antigenic changes for consideration in sagacious epitope selection.
ARTICLE | doi:10.20944/preprints202207.0368.v1
Subject: Engineering, Mechanical Engineering Keywords: Systems Engineering; Kane Damper; Forward Error Correction; Matched Filtering
Online: 25 July 2022 (09:35:15 CEST)
Within the past decade, the aerospace engineering industry has evolved outside the constraints of using single, large, custom satellites. Due to increased reliability and robustness of commercial off the shelf (COTS) printed circuit board (PCB) components, missions instead have transitioned towards deploying swarms of smaller satellites. This approach significantly decreases the mission cost by reducing custom engineering and deployment expenses. Nanosatellites are able to be quickly developed with a more modular design at lowered risk. The Alpha mission at Cornell Space Systems Studio is fabricated in this manner. However, for the purpose of this mission, only one satellite was initially developed. This manuscript will discuss a systems engineering approach to the development of this satellite. As a disclaimer, this manuscript is written from a systems perspective. Therefore it will follow many subsystems from a wide range of functionalities. The research in this manuscript was kept broad with the hope to contribute to the mission as a system, through a range of development phases including validation and verification of existing methods. The two systems that will be primarily focused on are the Attitude Control System (ACS) of the carrier nanosatellite (cubesat), and the RF communications on the ex-creted picosatellites (chipsat). Milestones achieved in chipsat RF include chipsat to chipsat communication, chipsat to SDR ground station communication, packet creation, error correction, appending a preamble, and filtering the signal. Achievements on the ACS side included controller traceability/verification and validation, software rigidity tests, hardware endurance testing, Kane damper and IMU tuning. These developments matured the technological readiness level (TRL) of our systems in preparation for satellite deployment.
REVIEW | doi:10.20944/preprints202201.0035.v1
Subject: Materials Science, Biomaterials Keywords: Cellulose; Biomedical; Wound healing; Drug delivery; Antibacterials; Tissue engineering
Online: 5 January 2022 (11:00:57 CET)
There are various biomaterials in nature, but none fulfills all the requirements. Cellulose, eco-friendly material-based biopolymers, have been advanced biomedicine to satisfy most market demand and circumvent many ecological concerns. This review aims to present an overview of the state of the art in cellulose's knowledge and technical biomedical applications. It included an extensive bibliography of recent research findings for fundamental and applied investigations. The chemical structure of cellulose allows modifications and simple conjugation with several materials, including nanoparticles, without tedious efforts. Cellulose-based materials were used for biomedicine applications such as antibacterial agents, antifouling, wound healing, drug delivery, tissue engineering, and bone regeneration. They advanced the applications to be cheap, biocompatible, biodegradable, easy for shaping and processing into different forms, with suitable chemical, mechanical and physical properties.
ARTICLE | doi:10.20944/preprints202111.0171.v1
Subject: Materials Science, Biomaterials Keywords: Hyaluronic acid; hydrogels; injectable; tissue engineering; endodontic tissue regeneration
Online: 9 November 2021 (13:27:21 CET)
Dental pulp tissue engineering (TE) quests to regenerate dentin/pulp complex by combining a suitable supporting matrix, stem cells, and biochemical stimuli. Such procedures foresee a matrix that can be easily introduced into the root canal system (RCS) and tightly adhere to dentin walls to assure the dentin surface's proper colonization with progenitor cells capable of restoring the dentin/pulp complex. Herein was investigated an injectable self-setting hyaluronic acid-based (HA) hydrogel system, formed by aldehyde-modified (a-HA) with hydrazide-modified (ADH), enriched with platelet lysate (PL), for endodontic regeneration. The hydrogels' working (wT) and setting (sT) times, the adhesion to the dentine walls, the hydrogel's microstructure, and the delivery of human Dental Pulp Cells (DPCs) were studied in vitro. Hydrogels incorporating PL showed a suitable wT and sT and a porous microstructure. The tensile tests showed that the breaking point occurs after 4.13 mm deformation. While in the indentation test after 1.3 mm deformation. Both breaking points occur in the hydrogel extension. The HA/PL hydrogels exhibited supportive properties and promoted cell migration toward dentin surfaces in vitro. Overall, these results support using PL-laden HA injectable hydrogels (HA/PL) as a biomaterial for DPCs encapsulation, thereby displaying great clinical potential towards endodontic regenerative therapies.
ARTICLE | doi:10.20944/preprints202109.0410.v1
Online: 23 September 2021 (13:07:12 CEST)
Cases of road cave-ins have been reportedly increasing globally and reports have associated this phenomenon to underground soil erosion due to defective sewer pipes. As the sewer pipes age, they may develop some defects which may lead to cracks and crevices that will lead to infiltration of the soils surrounding the pipe into the pipe, leading to the formation of cavities around the pipe. Therefore, this study investigated the factors behind the causes of underground soil erosion due to defective sewer pipes and proffered solutions for combating underground soil erosion due to defective sewer pipes. The study objective included; (a) establishing how the soil particle sizes affect the internal soil erosion due to defective sewer pipes, (b) determination of the effect of defect sizes on the internal soil erosion due to defective sewer pipes, (c) establishing the effect of the embedment material used on the internal soil erosion due to defective sewer pipes, (d) investigation of the type of soil erosion mechanism in the presence of a buried sewer pipe defect caused by the groundwater infiltration process. The methodology of the study involved reviewing and analyzing secondary qualitative and quantitative data. The findings established that the defect size of the pipe, the type and characteristics of the soil and the type of embedment materials used affected erosion of soil around a defective sewer pipe.
REVIEW | doi:10.20944/preprints202108.0514.v1
Subject: Keywords: radish; breeding; interspecific hybridization; molecular breeding; genomics; genetic engineering
Online: 26 August 2021 (16:46:36 CEST)
Radish is an annual herbaceous root crop, fruit, and oil crop plant belonging to the Cruciferae family. The important traits for radish breeding include high yield, early maturity, late bolting, pungency, cold-hardiness, drought resistance, heat tolerance, and soil adaptability. For successful radish production, need to the understand nature and behavior of the flower, and very important to identify the S haplotypes of parental lines to produce F1 hybrids based on self-incompatibility to get rid of laborious hand emasculation in radish. In radish some desirable genes are not present within varieties. Therefore, further breeding programmes depend on inter-specific and intra-specific hybridization, which has a vital role in genomic studies and crop improvement by introducing desirable agronomic characters. It is essential to acquire detailed genetic information on chromosomes and information on inheritance. Genomics is now at the core of crop improvement, and radish crop is exploited to study the underlying differences in genotypes. But some monogenic characters are improved by genetic engineering. A three-decade span following the first documented instance of genetic engineering has witnessed its application's unprecedented growth. Researchers have successfully produced transgenic radishes with various agronomic characteristics over the last decade.
REVIEW | doi:10.20944/preprints202105.0512.v1
Subject: Materials Science, Metallurgy Keywords: Materials; Magnesium; Magnesium Alloys; Engineering Materials; Biomaterials; Properties; Applications
Online: 21 May 2021 (09:42:52 CEST)
Magnesium is a promising material. It has a remarkable mix of mechanical and biomedical properties that made it suitable for a vast range of applications. With alloying, many of these inherent properties can be further improved. Today, it is primarily used in the automotive, aerospace, and medical industry. However, magnesium has its own set of drawbacks which the industry and research community are actively addressing. Magnesium’s rapid corrosion is its most significant drawback, and it dramatically impeded magnesium’s growth and expansion into other applications. This article will review both the engineering and biomedical aspects and applications for magnesium and its alloys. It will also elaborate on the challenges the material faces, how they can be overcome, and its outlook.
ARTICLE | doi:10.20944/preprints202104.0047.v2
Subject: Materials Science, Biomaterials Keywords: Hydrogels; Sodium alginate; Betamethasone; Drug delivery; Cartilage tissue engineering
Online: 6 April 2021 (10:03:04 CEST)
Hydrogels obtained from the combination of different polymers are an interesting strategy for the development of controlled release system platforms and tissue engineering scaffolds. In this study, the applicability of sodium alginate-g-(QCL-co-HEMA) hydrogels for these biomedical applications was evaluated. Hydrogels were synthesized by free-radical polymerization using different concentration of the components. The hydrogels were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, and swelling degree; betamethasone release as well as the in vitro cytocompatibility with chondrocytes and fibroblast cells were also evaluated. Scanning electron microscopy confirmed the porous surface morphology of the hydrogels in all cases. The swelling percent was determined at different pH and was observed to be pH-sensitive. The controlled release behavior of betamethasone from the matrices was investigated in PBS media (pH = 7.4) and the drug was released in a controlled manner up to 8 h. Human chondrocytes and fibroblasts were cultured on the hydrogels. The MTS assay shown that almost all hydrogels are cytocompatibles and an increase the proliferation in both cell types after one week of incubation was observed by Live/Dead® assay. These results demonstrate that these hydrogels are attractive materials for pharmaceutical and biomedical applications due to their characteristics, their release kinetics and biocompatibility.
Subject: Engineering, Automotive Engineering Keywords: Reaction engineering; Catalysis; particle; multiplicity; parallel reactions; consecutive reactions;
Online: 17 March 2021 (11:13:56 CET)
The steady-state multiplicity of the porous, non-isothermal, catalyst pellet when two parallel and consecutive chemical reactions take place was analysed in this work. The geometry selected for the catalyst pellet is finite hollow cylinder. A numerical multigrid continuation technique with the preconditioned conjugate gradient squared as coarse grid solver was used. The continuation parameter is the dimensionless adiabatic heat rise (Prater number) for the first chemical reaction. The effect of the other governing parameters was analysed and the results are compared to those provided by the single chemical reaction.
ARTICLE | doi:10.20944/preprints202101.0594.v1
Subject: Materials Science, Biomaterials Keywords: Hybrid scaffold; Bioactive Glass; Gelatin; GPTMS; Bone tissue engineering
Online: 28 January 2021 (16:13:18 CET)
Hybrid scaffolds based on bioactive glass (BAG) particles (<38µm), covalently linked to the gelatin (G*), using 3-glycidoxypropyltrimethoxysilane (GPTMS), have been studied for bone bioengineering. In this study, two glass compositions (13-93 and 13-93B20 [where 20% of the SiO2 was replaced with B2O3]) were introduced in the gelatin matrix. The Cfactor (Gelatin/GPTMS molar ratio) was kept constant at 500. The hybrids obtained were found to be stable at 37°C, in solution; condition at which pure gelatin is liquid. All hybrids were characterized by in vitro dissolution in TRIS solution (for up to 4 weeks) and Simulated Body Fluid (SBF) (for up to 2 weeks). Samples processed with 13-93B20 exhibit a faster initial dissolution and significantly faster precipitation of a hydroxyapatite (HA) layer. The faster ion release and HA precipitation recorded from the G*/13-93B20 samples, is attributable to the higher reactivity of borosilicate compared to the silicate glass. MC3T3-E1 cells behavior, in direct contact with the hybrids, was investigated, showing that the cells were able to proliferate and spread on the developed biomaterials. Tailoring the glass composition allows to better control the material’s dissolution, biodegradability, and bioactivity. Bioactive (especially with 13-93B20 BAG), and biocompatible, the hybrids are promising for bone application.
REVIEW | doi:10.20944/preprints202101.0517.v1
Subject: Life Sciences, Biochemistry Keywords: Gram-negative bacterial; Metabolite transporter; pathways; metabolic engineering approaches
Online: 25 January 2021 (15:49:13 CET)
Metabolite transport across cellular membranes is a key feature of living organisms. Specialized proteins or protein complexes mediate such transport processes and are accessible to genetic engineering approaches. This special issue will reflect on the different transport between cellular compartments. It will provide an overview about different transporter classes and metabolic engineering approaches in different organisms ranging from Bacteria to Eukarya. The transport mechanisms energetics of these compounds were thought little of, and most consideration was given to the designing of metabolic pathways. Gram-negative microbes discharge a wide scope of proteins whose capacities incorporate biogenesis of organelles, for example, pilli and flagella, supplement securing, destructiveness, and efflux of medications and different poisons. Six particular emission frameworks have been appeared to intervene protein send out through the inward and external layers of Gram-negative microbes. These pathways are exceptionally monitored all through the Gram-negative bacterial species. In Gram-positive microscopic organisms, discharged proteins are usually moved across the single layer by the Sec pathway or the two-arginine (Tat) pathway. Recently efforts focused on transporter and metabolite engineering, visualize the improvement and enhancement of microbial cell to pass such metabolites these metabolite carrier proteins are inserted into the inner membrane of mitochondria across the inner membrane, specialized carrier proteins are necessary that mediate the transport into and out of the mitochondrial matrix. Two main strategies for metabolic engineering in plants: the introduction of genes encoding new enzymes and the use of TFs controlling specialized metabolic pathways
ARTICLE | doi:10.20944/preprints202012.0125.v1
Subject: Materials Science, Biomaterials Keywords: biomaterials; cell control; chitosan; polyvinyl alcohol; scaffold; tissue engineering
Online: 7 December 2020 (07:30:10 CET)
Scaffolds are widely used in tissue engineering because their manufacture is based on natural and synthetic polymers, which allows them to have properties such as biocompatibility and biodegradability, creating an ideal environment for cell growth on their surface. In this context, among the polymers studied in Tissue Engineering are Chitosan (CH) and Polyvinyl Alcohol (PVA). CH is a versatile polymer obtained from de-acetylation of chitin, which is used for its high biodegradability and biocompatibility, although its mechanical properties must be improved. It has been found that one of the ways to improve the mechanical properties of CH is to mix it with other synthetic polymers such as PVA. PVA is known for its biocompatibility, biodegradability, zero toxicity and ease of preparation due to its solubility in water and excellent mechanical properties, such as tensile strength and ease in the formation of films and barriers. In this study we evaluated the capacity of scaffolds made with CH and PVA in different concentrations (2: 1, 1: 1, 1: 2, respectively) as a possible application in bone regeneration. This was made through different characterization tests such as Infrared Spectroscopy, AFM, Swelling test and Porosity test, where we obtained information about its structural and physicochemical properties. Additionally, a cellular quality control was performed on the material through the MTT assay. The Fourier transform infrared spectroscopy (FTIR) study showed that there are strong intermolecular hydrogen bonds between the chitosan and polyvinyl alcohol molecules. The Swelling and Porosity tests showed favorable results, obtaining maximum values of 5519% and 72.17% respectively. MTT tests determined that the prepared materials are not cytotoxic. These findings suggest that scaffolds possess properties suitable for use in Tissue Engineering.
REVIEW | doi:10.20944/preprints202011.0196.v1
Subject: Materials Science, Biomaterials Keywords: Antimicrobial polymers; dental materials; cranio-maxilifacial regeneration; tissue engineering
Online: 4 November 2020 (12:47:55 CET)
Cranio-maxillofacial structure is a region of particular interest in the field of regenerative medicine due to both its anatomical complexity and the numerous abnormalities affecting this area. However, this anatomical complexity is what makes possible the coexistence of different microbial ecosystems in the oral cavity and the maxillofacial region, contributing to the increased risk of bacterial infections. In this regard, different materials have been used for their application in this field. These materials can be obtained from natural and renewable feedstocks or by synthetic routes with desired mechanical properties, biocompatibility and antimicrobial activity. Hence, in this review, we have focused on bio-based polymers, which by their own nature, by chemical modifications of their structure, or by their combination with other elements, provide a useful antibacterial activity as well as the suitable conditions for cranio-maxillofacial tissue regeneration. This approach has not been reviewed previously, and we have specifically arranged the content of this article according to the resulting material and its corresponding application, reviewing guided bone regeneration membranes; bone cements; and devices and scaffolds for both soft and hard maxillofacial tissue regeneration, including hybrid scaffolds, dental implants, hydrogels and composites.
ARTICLE | doi:10.20944/preprints202010.0323.v1
Subject: Engineering, Automotive Engineering Keywords: Image segmentation; sonar image; ocean engineering；morphological image processing
Online: 15 October 2020 (13:10:41 CEST)
It has remained a hard nut for years to segment sonar images, most of which are noisy images with inevitable blur after noise reduction. For the purpose of solutions to this problem, a fast segmentation algorithm is proposed on the basis of the gray value characteristics of sonar images. This algorithm is endowed with the advantage in no need of segmentation thresholds to be calculated. To realize this goal, it follows the undermentioned steps: first, calculate the gray matrix of the fuzzy image background. After adjusting the gray value, segment the region into the background region, buffer region and target regions. After filtering, reset the pixels with gray value lower than 255 to binarize images and eliminate most artifacts. Finally, remove the remaining noise from images by means of morphological image processing. The simulation results of several sonar images show that the algorithm can segment the fuzzy sonar image quickly and effectively, with no problem of incomplete image target shape. Thus, the stable and feasible method is testified.
REVIEW | doi:10.20944/preprints202010.0149.v1
Subject: Biology, Anatomy & Morphology Keywords: breeding; diversity; genetic engineering; genomics; male sterility; melon; QTLs
Online: 7 October 2020 (09:22:33 CEST)
Melon (Cucumis melo L.) a member of family Cucurbitaceae is extensively cultivated for its fleshy fruits. Based on the specific agro-climatic zones of cultivation as well as concerning the regional preferences, melon displays significant variability phenotypic and biochemical attributes. Below, an effort is put forth to considerably evaluate the scope of achievements while in the growth as well as the enactment of melon breeding programs by employing the newest solutions. Melon breeding has achieved critical milestones throughout the previous century, and we hope this trend will go on to persist down the road. However, studies have to determine new genetic information for genes associated with the challenges imposed by climate change. The identification of valuable hereditary and also metabolic variability in the form of landraces and melon wild relatives will be useful for harvest diversification and also for the broadening of the cultivated melon genetic base. Whereas, considerable information on genomics, and melon metabolomics, is beneficial for dissecting the basis of the inheritance of important traits and their impact on the former characteristics. Overall, we hope the manuscript is going to serve as a crucial resource for the melon breeders.
ARTICLE | doi:10.20944/preprints202010.0107.v1
Subject: Life Sciences, Biochemistry Keywords: Bioprinting; microextrusion; tissue engineering; bioink; open-source; stem cells
Online: 6 October 2020 (08:24:54 CEST)
Three-dimensional (3D) bioprinting promises to be essential in tissue engineering for solving the rising demand for organs and tissues. Some bioprinters are commercially available, but their impact on the field of TE is still limited due to their cost or difficulty to tune. Herein, we present a low-cost easy-to-build printhead for microextrusion-based bioprinting (MEBB) that can be installed in many desktop 3D printers to transform them into 3D bioprinters. We can extrude bioinks with precise control of print temperature between 2 - 60 ºC. We validated the versatility of the printhead, by assembling it in three low-cost open-source desktop 3D printers. Multiple units of the printhead can also be easily put together in a single printer carriage for building a multi-material 3D bioprinter. Print resolution was evaluated by creating representative calibration models at different temperatures using natural hydrogels such as gelatin and alginate, and synthetic ones like poloxamer. Using one of the three modified low-cost 3D printers, we successfully printed cell-laden lattice constructs with cell viabilities higher than 90% after 24h post printing. Controlling temperature and pressure according to the rheological properties of the bioinks was essential in achieving optimal printability and great cell viability. The cost per unit of our device, which can be used with syringes of different volume, is less expensive than any other commercially available product. These data demonstrate an affordable open-source printhead with the potential to become a reliable alternative to commercial bioprinters for any laboratory.
ARTICLE | doi:10.20944/preprints202004.0306.v1
Subject: Mathematics & Computer Science, Information Technology & Data Management Keywords: requirements planning; search-based software engineering; verbal decision analysis
Online: 17 April 2020 (17:10:16 CEST)
In the software development process, the decision-maker (DM) has a range of problems inherent to its function. Wrong choices during software planning can bring great risk to the project. Therefore, the planning of software releases to be delivered to the customer should be well done. This is not an easy task because releases are made up of many requirements that contain complex variables that must be considered, such as precedence, cost, requirement stability, among other features that make the requirements-selection process challenging. To make this process less exhaustive, DM can use tools that facilitate this work. In software engineering, we can find fields of research specialists in this context, such as Search-Based Software Engineering (SBSE). The SBSE makes use of advanced metaheuristics to search for optimal solutions or the closest to it. In this work, we try to use another field of research to solve this same problem type, the Verbal Decision Analysis (VDA). To do this, we elaborate a workflow that will use the same source data, execute two solutions using the two search fields (SBSE and VDA) and compare the results. In the end, we evaluated and commented on the results.
ARTICLE | doi:10.20944/preprints201910.0370.v1
Subject: Engineering, Biomedical & Chemical Engineering Keywords: polyurethane; polylactide; tissue engineering; skin scaffold; antibacterial; degradable; medical
Online: 31 October 2019 (09:52:06 CET)
The aim of performed studies was to fabricate an antibacterial and degradable scaffold that may be used in the field of skin regeneration. To reach the degradation criterion the biocompatible polyurethane (PUR), obtained by using amorphous macrodiol α,ω-dihydroxy(ethylene-butylene adipate) macrodiol (PEBA), was used and processed with so-called “fast-degradable” polymer polylactide (PLA) (5 wt% or 10 wt%). To meet the antibacterial requirement obtained hybrid PUR-PLA scaffolds (HPPS) were modified with ciprofloxacin (Cipro) (2 wt% or 5 wt%), the fluoroquinolone antibiotic inhibiting growth of bacteria such as Pseudomonas aeruginosa, Escherichia Coli and Staphylococcus aureus, which are main cause of wound infections. Obtained unmodified and Cipro-modified HPPS were studied towards their chemical composition to detect presence or absence of characteristic functional groups of PUR, PLA and Cipro, and as well to indicate the participation of hydrogen bonds in the HPPS structure in dependence on PLA addition and ciprofloxacin modification. Mechanical properties were studied to determine the possible application of HPPS as a skin tissue scaffold. Scanning electron microscopy (SEM) was used to study morphology of unmodified and Cipro-modified HPPS and to performed elementary analysis by using energy-dispersive x-ray spectroscopy (EDX) of obtained materials. Finally, the microbiological tests were performed to indicate the antibacterial effect of Cipro-modified HPPS on S.aureus growth. Performed studies showed that Cipro-modified HPPS, obtained by using 5 % of PLA, possess suitable mechanical characteristic, morphology, degradation rate and demanded antimicrobial properties to be further developed as a potential scaffolds for skin tissue engineering.
Subject: Physical Sciences, Optics Keywords: TiO2 nanotubes; photonic crystals; optical engineering; theory and simulation
Online: 26 March 2019 (10:41:49 CET)
Two-dimensional arrays of hollow nanotubes made of TiO2 are a promising platform for sensing, spectroscopy and light harvesting applications. Their straightforward fabrication via electrochemical anodization, growing nanotube pillars of finite length from a Ti foil, allows precise tailoring of geometry and, thus, material properties. We investigate these photonic crystal structures with respect to reduction of front surface reflection, achievable field enhancement, and photonic bands. With the Rigorous Coupled Wave Analysis (RCWA), we study the optical response of photonic crystals made of thin-walled nanotubes relative to the bare Ti foil substrate, including under additional charge carrier doping.
REVIEW | doi:10.20944/preprints201810.0312.v1
Subject: Materials Science, Nanotechnology Keywords: upconversion; nanoparticles; lanthanide; surface modification; functionalisation; ligand engineering; silanisation;
Online: 15 October 2018 (12:59:30 CEST)
Lanthanide ion doped upconversion nanoparticles (UCNPs) that can convert low-energy infrared photons into high-energy visible and ultraviolet photons, are becoming highly sought-after for advanced biomedical and biophotonics applications. Their unique luminescent properties enable UCNPs to be applied for diagnosis, including biolabeling, biosensing, bioimaging and multiple imaging modality, as well as therapeutic treatments including photothermal and photodynamic therapy, bio-reductive chemotherapy and drug delivery. For the employment of the inorganic nanomaterials into biological environment, it is critical to bridge the gap in between nanoparticles and biomolecules via surface modifications and subsequent functionalisation. This work reviews the various ways to surface modify and functionalise UCNPs so as to impart different functional molecular groups to the UCNPs surfaces for a board range of applications in biomedical areas. We discussed commonly used base functionalities, including –COOH, -NH2 and –SH, that are typically imparted to UCNP surfaces so as to provide further functional capacity.
REVIEW | doi:10.20944/preprints201808.0280.v1
Subject: Materials Science, Biomaterials Keywords: conductive hydrogel; tissue engineering; biomaterials; physical and electrical properties
Online: 15 August 2018 (16:12:51 CEST)
In the field of tissue engineering, conductive hydrogels have been the most effective biomaterials to mimic the biological and electrical properties of tissues in the human body. The main advantages of conductive hydrogel include not only its physical properties, but also its adequate electrical properties, thus providing electrical signals to cells efficiently. However, when introducing a conductive material into a non-conductive hydrogel, a conflicting relationship between the electrical and mechanical properties may develop. This review examines the strengths and weaknesses of the generation of conductive hydrogels using various conductive materials and introduces the use of these conductive hydrogels in tissue engineering applications.
ARTICLE | doi:10.20944/preprints201807.0021.v1
Subject: Materials Science, Biomaterials Keywords: biomaterials; cobalt ferrites; poly(hydroxybutyrate-co-hydroxyvalerate); tissue engineering
Online: 3 July 2018 (05:12:53 CEST)
Polymer-based piezoelectric biomaterials have already proven their relevance for tissue engineering applications. Further, the morphology of the scaffolds plays also an important role in cell proliferation and differentiation. The present work reports on poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV), a biocompatible, biodegradable and piezoelectric biopolymer that has been processed in different morphologies, including films, fibres, microspheres and 3D scaffolds. Further, the corresponding magnetically active PHBV-based composites were also produced. The effect of the morphology on physico-chemical, thermal, magnetic and mechanical properties of pristine and composites samples was evaluated, as well as their cytotoxicity. It was observed that the morphology does not strongly affect the properties of the pristine samples but the introduction of cobalt ferrites induces changes in the degree of crystallinity that could affect the applicability of prepared biomaterials. Young modulus is dependent of the morphology and also increases with the addition of cobalt ferrites. Both, pristine and PHBV/cobalt ferrite composite samples are no cytotoxic, indicating their suitability for tissue engineering applications.
ARTICLE | doi:10.20944/preprints201806.0291.v1
Subject: Engineering, Marine Engineering Keywords: coastal defense; risk maps; non-engineering measure; coastal vulnerability
Online: 19 June 2018 (10:41:27 CEST)
In this study, we used the natural and anthropogenic characteristics of a coastal region to generate risk maps showing vulnerability and potential hazards, and proposed design criteria for coastal defense and land use for the various kinds of risks faced. The Yunlin coast: a first-level protection area in mid-west Taiwan, was then used as an example to illustrate the proposed design criteria. The safety of the present coastal defenses and land use of the Yunlin coastal area was assessed, and coastal protection measures for hazard prevention were proposed based on the generated risk map. The results can be informative for future coastal management and the promotion of sustainable development of coastal zones.
ARTICLE | doi:10.20944/preprints201703.0011.v1
Subject: Medicine & Pharmacology, Dentistry Keywords: Poly (lactic acid); chitosan; calcium silicate; tissue engineering; osteogenesis
Online: 1 March 2017 (17:03:43 CET)
Electrospinning is the versatile technique to generate large quantities of micro- or nano-fibers from a wide variety of shapes and sizes of polymer. Natural bone is a hierarchically composites with the dispersion of inorganic ceramic along organic polymer. The aim of this study, the electrospun poly (lactic acid) (PLA) mats coated with chitosan (CH) and calcium silicate (CS) powder were fabricated. The morphology, chemical composition, and surface properties of CS/CH-PLA composites were characterized by scanning electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy. In vitro, the CS/CH-coated PLA mats increased the formation of apatite on the surface when soaking in cell cultured medium. During culture, the adhesion and proliferation of the human mesenchymal stem cells (hMSCs) cultured on CS/CH-PLA were significantly promoted relative to those on PLA. Collagen I and fibronectin levels and promoted cell adhesion were observed upon an increase in CS content. Further, compared to PLA mats without CS/CH, CS10 and CS15 mats markedly enhanced the proliferation of hMSCs as well as their osteogenesis properties, which was characterized by bone-related gene expression. Our results demonstrated that the biodegradable and electroactive CS/CH-PLA mats had potential application as an ideal candidate for bone tissue engineering. Together, findings from this study clearly demonstrated that PLLA-C2S composite scaffold may function as an ideal candidate for bone tissue engineering.
ARTICLE | doi:10.20944/preprints201611.0150.v1
Subject: Materials Science, Biomaterials Keywords: water-based polyurethane; hyaluronic acid; cartilage tissue engineering; scaffold
Online: 30 November 2016 (04:28:15 CET)
Diseases in articular cartilages have affected millions of people globally. Although the biochemical and cellular composition of articular cartilages is relatively simple, there is the limitation in self-repair ability of cartilage. Therefore, developing the strategies for cartilage repair is very important. Here, we reported a new manufacturing process of water-based polyurethane based photosensitive materials with hyaluronic acid and applied the materials for 3D printed customized cartilage scaffolds. The scaffold has high cytocompatibility and is one that closely mimics the mechanical properties of articular cartilages. It is suitable for culturing human Wharton's jelly mesenchymal stem cells (hWJMSCs) and the cells showed an excellent chondrogenic differentiation capacity. We consider that the 3D printing hybrid scaffolds may have potential in customized tissue engineering and facilitate the development of cartilage tissue engineering.
ARTICLE | doi:10.20944/preprints202207.0433.v1
Subject: Engineering, Industrial & Manufacturing Engineering Keywords: advanced industrial engineering; strategy; management; business performance; key performance indicators
Online: 28 July 2022 (08:43:32 CEST)
The paper deals with the design of a systematic procedure for implementing strategy changes into internal business processes for a project-oriented production type of organization. In the first part of the contribution, a summary of the theoretical starting points for the field of strategic management and change management is presented. In the second part, the contribution deals with the analysis of the current situation in the area of the impact of the change of strategy on the management of business processes. In the last part, the proposal of the procedure for implementing strategy changes into internal business processes and the verification results are presented. The proposed procedure includes steps where the selection and verification of key performance indicators at individual levels of management plus the quantification of the impact of the change in strategy on the processes takes place. The management can thus monitor and evaluate the chosen processes in accordance with the fulfilment of the chosen strategy of the company. The last chapter presents the verification of the proposal for the systematic introduction of changes into the processes.
ARTICLE | doi:10.20944/preprints202206.0226.v1
Subject: Engineering, Industrial & Manufacturing Engineering Keywords: sustainable development; ecometallurgy; metallurgical econology; metallurgical ecosociology; sustainable materials engineering
Online: 15 June 2022 (11:08:37 CEST)
As a 21st century trend, sustainability has encompassed the entire world economy, including industry. Today the concept of "Industry 4.0" is known, resulting from advances in ICT (information and communication technologies). In recent years, companies in the metal materials industry have also implemented strategies and technologies belonging to the Industry 4.0 concept. The main purpose of the manuscript is to identify the key issues in the evolution of the development of the metal materials industry. The transition to a higher level of its evolution is based on two vectors, namely: the ecological paradigm, as a vector of in-depth knowledge, and sustainable material, as a vector that ensures sustainability in the areas of convergence of systems in the spheres of life and social consciousness. The systems that have an impact on the sustainable development of the metallic materials industry, through the interactions between them, are: the technological system, the social system and the natural-ecological system. Global knowledge re-quires the use of all inter and multidisciplinary knowledge, which ultimately contributes to the definition and characterization of new intersystem scientific branches: Ecometallurgy, Metallurgical Economics, Metallurgical Ecosociology and Sustainable Materials Engineering. The paper is considered a research study based on elements such as: literary foundations, using databases such as Web of Science (WoS), Scopus, Google Scholar, sustainable universal principles and legislative parameters.
ARTICLE | doi:10.20944/preprints202107.0259.v1
Subject: Engineering, Automotive Engineering Keywords: Driveability; low-frequency; energy path analysis; powertrain; model-based engineering
Online: 12 July 2021 (12:21:24 CEST)
Vehicle driveability is one of the important vehicle attributes in range-extender electric vehicles due to the electric motor torque characteristics at low-speed events. The process of validating and rectifying vehicle driveability attributes is typically utilised by a physical vehicle prototype that can be expensive and required several design iterations. In this paper, a model-based energy method to assess vehicle driveability is presented based on a high-fidelity 49 degree-of-freedom powertrain and vehicle systems. Multibody dynamics components were built according to their true centre of gravity relative to the vehicle datum for providing an accurate system interaction. The work covered a frequency at less than 20 Hz. The results that consisted of the component frequency domination are structured and examined to identify the low-frequency sensitivity based on different operating parameters such as a road surface coefficient. An energy path technique was also implemented on the dominant component by decoupling its compliances to study the effect on the vehicle driveability and low-frequency response. The outcomes of the research provided a good understanding of the interaction across the sub-systems levels. The powertrain rubber mounts were the dominant components that controlled the low-frequency contents (< 15.33 Hz) and can change the vehicle driveability quality.
ARTICLE | doi:10.20944/preprints202107.0056.v1
Subject: Engineering, Automotive Engineering Keywords: vibrations; dynamics; sounding rocket; vibration filtering; signal processing; space engineering
Online: 2 July 2021 (14:10:51 CEST)
Determining the vibration environment is crucial to analyzing a design of any mechanical system, especially such dynamic systems as sounding rockets. Accuracy of measurement using accelerometers could be improved by application of mechanical vibration filtering and amplifying devices. This work presents a theoretical description of a tunable filter and amplifier. Principle of work is provided as well as results from application of the device on a sounding rocket are provided. It is shown that implementation of such devices allowed for enhancing the accuracy of acceleration measurements. Conclusions on future implementations are also provided.
Subject: Materials Science, Biomaterials Keywords: Bioactive glasses; Alkali-free; Sol-gel; Bone regeneration; Tissue engineering.
Online: 1 July 2021 (11:20:51 CEST)
In bone tissue engineering, ceramics have been the choice due to their excellent biological properties. But the paradigm changed with the discovery of bioactive glasses (BGs) in 1969 by Larry Hench and co-workers, due to their ability to bond to living tissues through the formation of an interfacial bone-like hydroxyapatite layer when the bioglass was put in contact with biological fluids in vivo. Among a number of tested compositions, the one exhibiting the highest bioactivity index is the well-known trademarked 45S5 Bioglass®. The topic received increasing attention particularly after 1985 when this material entered in the market of biomedical devices, inspiring many other investigations aiming at further exploring the in vitro and in vivo performances of this BG, or developing other related BG compositions. The research efforts gradually revealed a number of shortcomings of 45S5 Bioglass®, mostly derived from its high sodium content, initially intended to decrease the melting temperature and accelerating the degradation of the silicate network over time. But the extensive release of sodium from 45S5 Bioglass® in the biological fluids creates a high pH cytotoxic environment. Other serious drawbacks include a fast degradation rate, and a poor sintering ability, which hinders the reliable fabrication of porous scaffolds. Therefore, sol-gel was regarded as an attractive alternative to prepare alkali-free BG compositions. The process uses inorganic and/or organic precursors, which undergo hydrolysis and condensation at room-temperature, being less costly. When properly conducted, the sol-gel process might result in amorphous structures with all the components intimately mixed at the atomic scale. Moreover, developing new better performing materials for bone tissue engineering is a growing concern, as the ageing of the world’s population leads to lower bone density and osteoporosis. This work describes the sol-gel synthesis of a novel quaternary silicate-based BG with the composition 60 SiO2 – 34 CaO – 4 MgO – 2 P2O5 (mol%) was prepared using acidified distilled water as single solvent. By controlling the kinetics of the hydrolysis and condensation steps, an amorphous glass structure could be obtained. The results of XRD of samples calcined within the temperature range from 600-900 ºC demonstrated that amorphous nature was maintained until 800 ºC, followed by partial crystallization at 900 ºC. The specific surface area, an important factor in osteoconduction, was also evaluated over different temperatures, ranging from 160.6 ± 0.8 m2/g at 600 ºC down to 2.2 ± 0.1 m2/g at 900 ºC, being accompanied consistent changes in average pore size and agreeing pore size distribution. The immersion of the BG particles in simulated body fluid (SBF) led to the formation of an extensive apatite layer on its surface. These overall results indicate the proposed material is very promising for biomedical applications in bone regeneration and tissue engineering.
ARTICLE | doi:10.20944/preprints202104.0028.v1
Subject: Mathematics & Computer Science, Algebra & Number Theory Keywords: Software Engineering; Model; Model-Driven; Model Driven Development; MDD; MDA
Online: 1 April 2021 (14:47:55 CEST)
In Model-Driven Development (MDD), the models, their generation, and imposing changes on them (model transformation) are used for the development of software. Models provide a framework to start from the imagination and abstraction to create and accomplish the final system. Models create a slow and steady transition from whatness to howness, i.e. from the natural path of the generation of software. For supporting this path, the Logic and Functionality of software must be changeable during its evolution. Here we provide a brief introduction to the concept of Model Driven Development.
REVIEW | doi:10.20944/preprints202102.0418.v1
Subject: Engineering, Automotive Engineering Keywords: Integrins; RGD; contractility; collagen tissue; engineering; adhesion molecules; myocardial infarct
Online: 18 February 2021 (12:23:02 CET)
Currently, the clinical impact of cell therapy after a myocardial infarction (MI) is limited by low cell engraftment due to significant cell death, including apoptosis, in an infarcted, inflammatory, poor angiogenic environment, low cell retention and secondary migration. Cells interact with their environment through integrin mechanoreceptors that control their survival/apoptosis/differentiation/migration/proliferation. Optimizing these interactions may be a way of improving outcomes. The association of free cells with a 3D-scaffold may be a way to target their integrins. Collagen is the most abundant structural component of the extracellular matrix (ECM) and the best contractility levels are achieved with cellular preparations containing collagen, fibrin, or Matrigel (i.e. tumor extract). In the interactions between cells and ECM, 3 main proteins are recognised: collagen, laminin and RGD (Arg-Gly-Asp) peptide. The RGD plays a key role in heart development, after MI, and on cardiac cells. Cardiomyocytes secrete their own laminin on collagen. The collagen has a non-functional cryptic RGD and is thus suboptimal for interactions with associated cells. The use of a collagen functionalized with RGD may help to improve collagen biofunctionality. It may help in the delivery of paracrine cells, whether or not they are contractile, and in assisting tissue engineering a safe contractile tissue.
REVIEW | doi:10.20944/preprints202011.0351.v1
Subject: Medicine & Pharmacology, Allergology Keywords: Cell therapy; MCAO; Stroke; Genetic engineering; Growth factors; Stem cells
Online: 12 November 2020 (14:25:43 CET)
The last two decades have witnessed a surge in investigations proposing stem cells as a promising strategy to treat stroke. Since growth factor release is considered as one of the most important aspects of cell-based therapy, stem cells over-expressing growth factors are hypothesized to yield higher levels of therapeutic efficiency. In pre-clinical studies of the last 15 years that were investigating the efficiency of stem cell therapy for stroke, a variety of stem cell types were genetically modified to over-express various factors. In this review we summarize the current knowledge on the therapeutic efficiency of stem cell-derived growth factors, encompassing techniques employed and time points to evaluate. In addition, we discuss several types of stem cells, including the recently developed model of epidermal neural crest stem cells, and genetically modified stem cells over-expressing specific factors, which could elevate the restorative potential of naive stem cells. The restorative potential is based on enhanced survival/differentiation potential of transplanted cells, apoptosis inhibition, infarct volume reduction, neovascularization or functional improvement. Since the majority of studies have focused on the short-term curative effects of genetically engineered stem cells, we emphasize the need to address their long-term impact.
Subject: Life Sciences, Biotechnology Keywords: metabolic engineering; biohydrogen production; microbes; co-culture; metabolic network analysis
Online: 19 July 2020 (20:43:36 CEST)
Hydrogen is useful as a fuel and could be produced by a variety of means. One approach uses artificial photosynthesis where energy from sunlight powers the splitting of water into hydrogen and oxygen. But, biological methods for producing hydrogen has emerged strongly over the past decades. In particular, specific microorganisms could use different substrates to produce hydrogen at differing yields. Such fundamental discoveries with industrial applications thus motivated the use of metabolic engineering approaches and methodologies in enhancing biological hydrogen production through a series of enzyme over-expression, pathway debottlenecking, and gene deletion. However, such approaches heavily rely on the selection of an appropriate microbial chassis for biohydrogen production. With the proper strain in hand, use of alternative substrates may engender greater hydrogen productivities. But learning from the bioprocessing field, co-culture of two compatible microorganisms have been sought after for improving biohydrogen production. In addition, thermophilic microbes may also be useful candidates for exploiting hydrogen production from composting. Future outlook in the field looks into filling our gaps in understanding of the metabolic network that feeds into hydrogen production in different organisms. But, more importantly, problems such as reduced growth rate in engineered microbes point to fundamental issues with using genetically engineered microorganisms for improved biohydrogen production, to which clever bioprocess engineering may yield solutions.
REVIEW | doi:10.20944/preprints202003.0461.v2
Subject: Engineering, Biomedical & Chemical Engineering Keywords: cell free protein synthesis; cell free metabolic engineering; metabolic modeling
Online: 30 April 2020 (05:19:00 CEST)
Cell free systems are a widely used research tool in systems and synthetic biology and a promising platform for manufacturing of proteins and chemicals. In the past, cell free biology was primarily used to better understand fundamental biochemical processes. Notably, E. coli cell free extracts were used in the 1960s to decipher the sequencing of the genetic code. Since then, the transcription and translation capabilities of cell free systems have been repeatedly optimized to improve energy efficiency and protein yield. Today, cell free systems, in combination with the rise of synthetic biology, have taken on a new role as a promising technology for just in time manufacturing of therapeutically important biologics and high-value small molecules. They have also been implemented in an industrial scale for the production of antibodies and cytokines. In this review, we discuss the evolution of cell free systems, advancements in cell free protein synthesis, and cell free metabolic engineering, and conclude with discussing the importance and feasibility of mathematical modeling in cell free systems.
ARTICLE | doi:10.20944/preprints202001.0088.v1
Subject: Engineering, Industrial & Manufacturing Engineering Keywords: human reliability analysis; safety; FRAM; resilience engineering; performance variability; emergency
Online: 9 January 2020 (13:22:43 CET)
Technological innovation has led to the development of increasingly efficient and complex industrial plants. To manage this complexity, it is necessary to define an integrated vision of the socio-technological system that includes: technological, human and organizational component. Petrochemicals can be considered one of the most complex socio-technical systems that deserve special attention to high risk management, especially during the emergency conditions. Traditional safety management models only consider static systems, while new resilience engineering models evaluate the performance variability developed between different actions. One of the recent development methods is the Functional Resonance Analysis Method (FRAM) that identifies the pairs between the functions. FRAM unfortunately is a qualitative model, this research integrates this model with the Performance Shaping Factors (PSFs) and with the Bayesian approach to identify the performance variability of the system. The analysis aims to develop a system that improves safety analysis. The proposed model is applied in a case study of an emergency in a petrochemical company.
REVIEW | doi:10.20944/preprints201910.0253.v1
Subject: Life Sciences, Biotechnology Keywords: tropical cash crops; coffee; cacao; papaya; chromosome engineering; synthetic biology
Online: 22 October 2019 (05:32:50 CEST)
Background Tropical and subtropical crops such as coffee, cacao, and papaya are valuable commodities and its consumption is a seemingly indispensable part of the daily lives of billions of people across the world. Conventional breeding in these crops is lengthy and yields are threatened by runaway global warming. In this review we propose the application of chromosome engineering and synthetic biology principles in order to enhance synthesis of key metabolites, and transmission of wild traits for resistance to stress and disease. Conclusions It is hoped that the adoption of such technological approaches may enhance the resilience of agricultural communities, lead to economic growth and secure the availability of key resources for generations to come.
ARTICLE | doi:10.20944/preprints201908.0139.v1
Subject: Physical Sciences, Condensed Matter Physics Keywords: 2D materials, molybdenum disulfide (MoS2), interlayer exciton, strain engineering, bilayer
Online: 12 August 2019 (11:43:12 CEST)
We show how the excitonic features of biaxial MoS2 flakes are very sensitive to biaxial strain. We find a lower bound for the gauge factors of the A exciton and B exciton of (-41 ± 2) meV/% and (-45 ± 2) meV/% respectively, which are larger than those found for single-layer MoS2. Interestingly, the interlayer exciton feature also shifts upon biaxial strain but with a gauge factor that is systematically larger than that found for the A exciton, (-48 ± 4) meV/%. We attribute this larger gauge factor for the interlayer exciton to the strain tunable van der Waals interaction due to the Poisson effect (the interlayer distance changes upon biaxial strain).
ARTICLE | doi:10.20944/preprints201812.0155.v1
Subject: Medicine & Pharmacology, Dentistry Keywords: Bone tissue engineering, magnesium implants, ISO norms, in vitro, PEO
Online: 12 December 2018 (15:43:04 CET)
Magnesium (Mg)-based biomaterials are promising candidates for bone and tissue regeneration. Alloying and surface modifications provide effective strategies for optimizing and tailoring their degradation kinetics. Nethertheless, biocompatibility analyses of Mg-based materials are challenging due to its special degradation mechanism with continous hydrogen release. In this context, the hydrogen release and the related (micro-) milieu conditions pretend to strictly follow in vitro standards based on ISO 10993-5/-12. Thus, special adaptions for the testing of Mg materials are necessary, which have been described in a previous study from our group. Based on these adaptions, further developments of a test procedure allowing rapid and effective in vitro cytocompatibility analyses of Mg-based materials based on ISO 10993-5/-12 are necessary. The following study introduces a new two-step test scheme for rapid and effective testing of Mg. Specimens with different surface characteristcis were produced by means of plasma electrolytic oxidation (PEO) using silicate-based and phosphate-based electrolytes. The test samples were evaluated for corrosion behavior, cytocompatibility and their mechanical and ostogenic properties. Thereby, two PEO ceramics could be identified for further in vivo evaluations.
REVIEW | doi:10.20944/preprints201811.0019.v1
Subject: Materials Science, General Materials Science Keywords: hydrogen; electrocatalysts; transition metal; layered material; heterostructure; hierarchical; surface engineering
Online: 2 November 2018 (05:16:22 CET)
Water splitting plays an important role in electrochemical and photoelectrochemical conversion of energy devices. Electrochemical water splitting by the hydrogen evolution reaction (HER) is a straightforward route to produce hydrogen (H2), which requires an efficient electrocatalysts to minimize energy consumption. Recent advances have created a rapid rise in new electrocatalysts, particularly those based on non-precious metals. In this review, we present a comprehensive overview of the recent developments of ternary and quaternary 6d-group transition metal chalcogenides (TMCs) based electrocatalysts for water splitting, especially for HER. Detailed discussion is organized from binary to quaternary TMCs including, surface engineering, heterostructures, chalcogen substitutions, and hierarchically structural design in TMCs. Moreover, emphasis is placed on future research scope and important challenges facing these electrocatalysts for further development in their performance towards water splitting.
ARTICLE | doi:10.20944/preprints201809.0609.v1
Subject: Engineering, Other Keywords: resilience engineering; disaster management; assessment model; capacity diagnosis; infectious disease
Online: 30 September 2018 (11:17:41 CEST)
Safety management assessment systems for national level units’ in South Korea focus on responding capacity to cope with impending accident occurrence and danger occurrence. Since the four stage systems for prevention-preparation-response-recovery, which are core elements of national disaster management, assess the capacities by item such as those of individuals, disaster management departments, institutions, and management networks, there is no assessment function for the organic operation states of the entire systems. Therefore, for efficient disaster management, systematic evaluation indices that will enable active pre-checks in departments in organizations should be developed in place of the existing simply checking methods. In this study, an assessment model that will enable active disaster management centered on practice was developed using resilience engineering techniques. This model consists of disaster management items from the viewpoint of proactive responses instead of prevention. A total of 56 items that constitute four capacities; which are prediction (13 items), monitoring (14 items), proactive response (15 items), and safety learning (14 items) capacities were adopted in this model through Delphi analysis. Institutional capacities for infectious disease disaster management were evaluated based on this model and the resultant scores were prediction 4.41, monitoring 4.63, proactive response 4.69, safety learning 4.56 out of the full score of 5.0 points with an overall average of 4.51. This is an excellent capacity management score comparable to the score 4.57 of diagnosis of similar capacities by the WHO\_JEE (The Joint External Evaluation) in 2017. In fact, in 2015, when infectious disease capacity management was poor, in case of MERS (Middle East Respiratory Syndrome) infectious disease spread in South Korea, 36 patients died and 6,729 patients were isolated. However, through capacity reinforcement, in the case of MERS occurrence in South Korea in September 2018, a management capacity that prevented spread was shown as one confirmed case was completely cured in 10 days and 21 contacts were isolated and tested negative. Therefore, this capacity management assessment model is judged to be usable in enhancing disaster response and management capacities.
ARTICLE | doi:10.20944/preprints201803.0270.v1
Subject: Arts & Humanities, Linguistics Keywords: chemical engineering; journal publications; lexical choices; collocations; impact factor; training
Online: 30 March 2018 (11:25:20 CEST)
The combination of increased pressures for high-volume, high-impact publications in English language with the high rejection rates of submitted manuscripts for publications presents an often unsurpassable obstacle for (early career) researchers. At the same, the register requirements of peer-reviewed journals -that can contribute to whether a paper is accepted for publication- has received little attention. This paper redresses this gap, by investigating the linguistic choices in 60 published manuscripts in four journals, with impact factor (IF) above 2; all 4 journals, publish original research papers in the field of chemical engineering science and specifically focus on wastewater treatment. Our survey shows that chemical engineering research publications tend to comply to a set of unwritten requirements: multidisciplinarity, brevity, co-authorship, focus on the description of practical results (rather than methods), and awareness of non-specialised audiences. It is found that less discipline-specific vocabulary was used in higher IF journals and this is interpreted within the current context of manuscript publication and consumption. Also, a complex relationship between the advertised scope of each journal and the actual published papers exists, indicating that guide for authors and aims and objective published by the journal's editorial office should be critically evaluated.
REVIEW | doi:10.20944/preprints202208.0493.v1
Subject: Engineering, Biomedical & Chemical Engineering Keywords: systematic review; time series classification; digital biomarkers; machine learning; feature engineering
Online: 29 August 2022 (12:42:39 CEST)
Background: Digital clinical measures collected via various digital sensing technologies such as smartphones, smartwatches, wearables, ingestible, and implantable are increasingly used by individuals and clinicians to capture health outcomes or behavioral and physiological characteristics of individuals. Time series classification (TSC) is very commonly used in modeling digital clinical measures. While deep learning models for TSC are very common and powerful, there exist some fundamental challenges. This review presents non-deep learning models commonly used for time series classification in biomedical applications that achieve high performance. Objective: We performed a systematic review to characterize the techniques used in time series classification of digital clinical measures throughout all stages of data processing and model building. Methods: We conducted a literature search on PubMed, and the Institute of Electrical and Electronics Engineers (IEEE), Web of Science, and SCOPUS databases using a range of search terms to retrieve peer-reviewed articles reporting academic research on digital clinical measures in the five year period between June 2016 and June 2021. We identified and categorized research studies based on the types of classification algorithms and sensor input types. Results: We found 452 papers in total from four different databases: PubMed, IEEE, Web of Science Database, and SCOPUS. After removing duplicates and irrelevant papers, 135 articles remained for detailed review and data extraction. Among these, engineered features using time series methods that were subsequently fed into widely-used machine learning classifiers was the most commonly used technique and also most frequently achieved the best performance metrics (77 out of 135 articles). Statistical modeling (24 out of 135 articles) algorithms were the second most common and also second best classification technique. Wavelet-based classification models (8 out of 135 articles) were also common. Electroencephalogram (29 out of 135 articles) was the most common data type used as an input. Accuracy was the most commonly reported performance metric, with 67.65% of articles reporting on accuracy. In this review paper, we provide summaries of signal pre-processing methods, feature engineering and selection methods, time series models, as well as model interpretations. Importantly, we found that about 50% of the papers only report one performance metric, which may result in a skewed view of overall performance. Conclusion: While high time series classification performance has been achieved in digital clinical, physiological, or biomedical measures, no standard benchmark datasets, modeling methods, or reporting methodology exist. There is no single widely used method for time series model development or feature interpretation– many different methods have proven successful.
REVIEW | doi:10.20944/preprints202106.0026.v2
Subject: Materials Science, Biomaterials Keywords: elastomers; hydrogels; elastomer-hydrogel systems; injectable biomaterials; adhesive surfaces; tissue engineering
Online: 20 April 2022 (11:39:28 CEST)
Novel advanced biomaterials have recently gained great attention, especially in surgical minimally invasive techniques. Applying sophisticated design and engineering methods, various elastomer-hydrogel systems (EHS) with outstanding performance have been developed in last decades. Those systems composed of elastomers and hydrogels are very attractive due to their high biocompatibility, injectability, controlled porosity and often antimicrobial properties. Moreover, elastomeric properties and bioadhesiveness are making them suitable for soft tissue engineering. Herein, we present the advances in current state-of-the-art design principles and strategies for strong interface formation inspired by nature (bio-inspiration), diverse properties and applications of elastomer-hydrogel systems in different medical fields, in particular, in tissue engineering. Functionalities of those systems, including adhesive properties, injectability, antimicrobial properties and degradability applicable to tissue engineering will be discussed in a context of future efforts towards development of advanced biomaterials.
REVIEW | doi:10.20944/preprints202204.0097.v1
Subject: Biology, Plant Sciences Keywords: Prolyl endoprotease; prolyl oligopeptidase; protease; protein engineering; proteolytic enzyme; proteomics; therapeutics
Online: 11 April 2022 (11:21:44 CEST)
Proteases or peptidases are hydrolases that catalyze the breakdown of polypeptide chains into smaller peptide subunits. Proteases exist in all life forms, including archaea, bacteria, protozoa, insects, animals, and plants, due to their vital functions in cellular processing and regulation. There are several classes of proteases in the MEROPS database based on their catalytic mecha-nisms. This review focuses on the post-proline cleaving enzymes (PPCEs), especially the prolyl endoprotease/oligopeptidase (PEP/POP). To date, most PPCEs studied are of microbial and ani-mal origins. Recently, there are reports of new plant PPCEs. The most common PEP/POP are members of the S9 family that comprise two conserved domains. The substrate-limiting β-propeller domain prevents unwanted digestion, while the α/β hydrolase catalyzes reaction at the carboxyl-terminal of proline residues. PPCEs have diverse applications, are widely used in the beer brewing industry, and have potential as therapeutic agents for Alzheimer’s disease and celiac disease by targeting proline-rich substrates. Protein engineering via mutagenesis has been performed to improve heat resistance, pepsin-resistant capability, specificity, and protein turno-ver of PPCEs for pharmacological applications. This is the first comprehensive review to cover the biotechnological applications of PPCEs and discuss the unique prolyl cleaving activity of dif-ferent enzymes based on the recent structure-function studies from diverse taxa.
ARTICLE | doi:10.20944/preprints202110.0382.v1
Subject: Mathematics & Computer Science, Artificial Intelligence & Robotics Keywords: statistical machine reading; metabolic engineering; concepts; terms and phrases; computational complexity
Online: 26 October 2021 (12:27:54 CEST)
The world of science is drowned in a wealth of information. How to make sense of this wealth of published articles, blog posts and abstracts has become an important challenge given the importance of science to different aspects of societal function. At the crux of the issue lies the increasing trend where scientific discovery informs decision making at the societal level. One example, is the elucidation of the ozone hole to the promulgation of the Montreal Protocol in 1987, and documenting increasing atmospheric carbon dioxide concentration led to climate action and signing of the Paris Agreement in 2015. Hence, understanding a research field becomes an important need for many decision makers across different sectors of society. But, the scientific literature is cryptic and esoteric, and presents a significant barrier to comprehension. One approach to ameliorate the problem is statistical machine reading, which provides the critical capability of identifying key concepts that underpins a research field. Such important concepts help provide an incision point to gain further understanding of the field and initiating further conversation about the field. This work sought to validate the concept of whether applying statistical machine reading to a body of literature comprising short blog posts and abstracts of published articles help in understanding the field of metabolic engineering. One important angle pursued in this research is whether the tabulated list of terms and phrases identified by statistical machine reading could be creatively analyzed to gain a deeper understanding of the research field. For example, the most frequently occurring terms and phrases could describe key concepts of the research field. Moving down in frequency occurrence would be terms and phrases that describe methodologies and approaches of the field. Finally, less frequently occurring terms and phrases may be tools and resources used in the research field. Results validated the utility of statistical machine reading in identifying important terms and phrases associated with the research field. But the small dataset of blog posts and abstracts used in this study severely hampered the identification of most of the key concepts of metabolic engineering, which is a fairly broad field of research. Overall, statistical machine reading shows utility in identifying terms and phrases that could describe a field. However, the level of understanding is closely tied in to the breadth and depth of reading material available, which meant that the methodology is data intensive in nature. Future use of supercomputing or quantum computing could help alleviate constraints of computational capacity, and help tackle the exponential rise in computational complexity as the size of the reading material for machine reading expands.
ARTICLE | doi:10.20944/preprints202106.0545.v1
Subject: Materials Science, Biomaterials Keywords: Bone tissue regeneration; injectable; bone graft; fracture; osteoblast; bone tissue engineering
Online: 22 June 2021 (14:22:33 CEST)
The occurrence of bone-related disorders and diseases has increased dramatically in recent years around the world. Demineralized bone matrix (DBM) has been widely used as a bone implant due to its osteoinduction and bioactivity. However, the use of DBM is limited because it is a particulate material, which makes it difficult to manipulate and implant with precision, in addition, these particles are susceptible to migrate to other sites. To address this situation, DBM is commonly incorporated into a variety of carriers. An injectable scaffold has advantages over bone grafts or preformed scaffolds, such as the ability to flow and fill the bone defect. The aim of this research is to develop a DBM carrier with such viscoelastic properties to obtain an injectable bone substitute (IBS). The DBM carrier developed consisted of a PVA/glycerol network cross-linked with borax and reinforced with CaCO3 as a pH neutralizer, porosity generator, and source of Ca. The physicochemical properties were determined by the injectability test, FTIR, SEM, and TGA. Porosity, degradation, bioactivity, possible cytotoxic effect, and proliferation in osteoblasts were also determined. The results show that the developed material has great potential to be used in bone tissue regeneration
REVIEW | doi:10.20944/preprints202104.0348.v1
Subject: Medicine & Pharmacology, Allergology Keywords: porous tantalum; clinical application; additive manufacturing; surface modification; bone tissue engineering
Online: 13 April 2021 (11:36:57 CEST)
Porous tantalum (Ta) is a promising biomaterial and has been applied in orthopedics and dentistry for nearly two decades. The high porosity and interconnected pore structure of porous Ta promise fine bone ingrowth and new bone formation within the inner space, which further guarantee rapid osteointegration and bone-implant stability in long term. Porous Ta has high wettability and surface energy that can facilitate adherence, proliferation and mineralization of osteoblasts. Meanwhile, low elastic modulus and high friction coefficient of porous Ta can effectively avoid stress shield effect, minimize marginal bone loss and ensure primary stability. Accordingly, the satisfactory clinical application of porous Ta based implants or prostheses are mainly derived from its excellent biological and mechanical properties. With the advent of additive manufacturing, personalized porous Ta based implants or prostheses have shown their clinical value in the treatment of individual patient who need specially designed implant or prosthesis. In addition, many modification methods have been introduced to enhance the bioactivity and antibacterial property of porous Ta with promising in vitro and in vivo research results. In any case, choosing suitable patients is of great importance to guarantee surgical success after porous Ta insertion.
ARTICLE | doi:10.20944/preprints202104.0228.v1
Subject: Arts & Humanities, Anthropology & Ethnography Keywords: Requirements Engineering; Authoring Tools; 3D content; IEEE 830 standard; Social Media
Online: 8 April 2021 (10:16:52 CEST)
This paper presents a requirements specification analysis for driving the design of new systems that will allow 3D media creators to further promote and monetize from their work. The provided requirements analysis is based on the IEEE 830 standard for requirements specification. It allows us to elucidate system requirements through existing (AS-IS) and envisioned (TO-BE) scenarios affected by the latest trends on design methodologies and content promotion in social media. A total of 30 tools for content creation, promotion and monetization are reviewed. The target groups, i.e. creator groups, are divided in 10 types according to their role in 3D media production. Based on this division 10 candidate TO-BE scenarios have been identified and out of these 10 scenarios, we have selected 6 scenarios for validation by media creators. The validation was performed through a survey of 24 statements on a 5 Likert scale by 47 individuals from the domains of Media, Fine arts, Architecture, and Informatics. Useful evaluation results and comments have been collected that can be useful for future systems design.
ARTICLE | doi:10.20944/preprints202102.0051.v1
Subject: Materials Science, Biomaterials Keywords: Metal-Organic Framework; Photocatalysis; Band-Gap modulation; Strain Engineering; Catalyst Selectivity.
Online: 1 February 2021 (15:00:06 CET)
In recent years, the class of metal-organic framework (MOF) materials emerged. These materials' unique properties can be assigned to their structure, containing inorganic nodes connected with organic linkers. Due to their porosity and flexibility, MOFs have become suitable for various energy-related applications, including gas storage, hydrogen production and heterogeneous catalysis, and photocatalysis. Using DFT+U calculations, we show that the substitution of metal centers in inorganic nodes and the strain engineering of UiO-66 alters the electronic and optical properties of this material. We show that applying mechanical strain on UiO-66 enables the control of absorption coefficient in the UV-Vis spectrum and the photocatalytic processes' selectivity when reactants for several photocatalytic processes are present. The presented findings could lead to general strategies for designing novel MOFs for sustainable energy conversion applications.
Subject: Medicine & Pharmacology, Allergology Keywords: 3D printing; tissue engineering; periodontal regeneration; scaffolds; stem cells; growth factors
Online: 24 November 2020 (16:18:17 CET)
The three-dimensional printing of scaffolds is an interesting alternative to the traditional techniques of periodontal regeneration. This technique uses computer assisted design and manufacturing after CT scan. After 3D modelling, individualized scaffolds are printed by extrusion, selective laser sintering, stereolithography, or powder bed inkjet printing. These scaffolds can be made of one or several materials such as natural polymers, synthetic polymers, or bioceramics. They can be monophasic or multiphasic and tend to recreate the architectural structure of the periodontal tissue. In order to enhance the bioactivity and have a higher regeneration, the scaffolds can be embedded with stem cells and/or growth factors. This new technique could enhance a complete periodontal regeneration. This review summarizes the application of 3D printed scaffolds in periodontal regeneration. The process, the materials and designs, the key advantages and prospects of 3D bioprinting are highlighted, providing new ideas for tissue regeneration.
ARTICLE | doi:10.20944/preprints202011.0537.v1
Subject: Engineering, Civil Engineering Keywords: BIM model; point cloud; tunnel engineering; data fusion; cross-section analysis
Online: 20 November 2020 (11:09:19 CET)
This paper introduces a method for tunnel point cloud and BIM model integration and cross-section monitoring, providing information to analyse tunnel cross-sections and surrounding rock deformation, and support for tunnel maintenance and reconstruction. Three types of data are processed for the integration: laser scanning point cloud, BIM tunnel model and terrain model from oblique photogrammetry. An adaptive BIM modelling scheme is proposed for tunnels with alien structures. Precise spatial registration of the data sets is conducted by applying singular value decomposition (SVD) algorithm to calculate transformation parameters from the point cloud model to the BIM model. Since the tunnel central line has high-order derivability, a cross-section calculation method based on tangent vector is proposed to obtain the cross-sectional profile of tunnels at any mileage. The proposed method has been verified by applying it to a tunnel reconstruction project. The experiment results show that the tunnel point cloud and the BIM model were highly coincident after the integration. The developed program can effectively get the cross-section of the tunnel at any mileage, and correctly express the spatial relationship between the BIM tunnel, the point cloud of tunnel and the external mountainous terrain.
REVIEW | doi:10.20944/preprints202006.0350.v1
Subject: Life Sciences, Biotechnology Keywords: Antibodies engineering; Computational approach; Novel drugs; Synthetic immunology; Next generation antibodies
Online: 28 June 2020 (20:24:49 CEST)
In the pre era of synthetic antibodies, pharmaceutical companies depend on finding novel drugs from medicinal plants and other traditional resources; while in present, technological advances in biology, computer and robotics give the researchers the ability to rewrite and edit DNA in order to synthesize very large sets of drug candidates; these novel and improved candidates serves the basis for creating another library of drug candidates and so on until we find the right biomolecule for the disease of interest. all these technologies combined together to synthesize therapeutic antibodies for many types of cancer, autoimmune diseases, and infectious diseases, that can address diseases much more readily to very rapidly get therapeutics into patients so that we can potentially have an impact on disease. The antibodies mechanism is recognize and bind to disease cells and pinpoint the immune system to attack those cells effectively. Now a days, they dependent on computational approach to guide and accelerate the process of antibodies engineering by combination of selection system and use of high-throughput data acquisition and analysis to build and construct populations of next generation antibodies that are thermo-stable, non-immunogenic as possible, and to be administered to many humans as possible. In this review, I will discuss the latest in silico methods for antibodies engineering.
ARTICLE | doi:10.20944/preprints201906.0111.v1
Subject: Social Sciences, Education Studies Keywords: education; University of the District of Columbia; engineering education; summer program
Online: 13 June 2019 (07:28:00 CEST)
Preparing high school students for engineering disciplines is crucial for sustainable scientific and technological developments in the USA. This paper discusses a pre-college program, which not only exposes students to various engineering disciplines but also enables them to consider engineering as the profession. The four-week long “Engineering Innovation (EI)” course is offered every year to high school students by the center of outreach, Johns Hopkins University. EI program is designed to develop problem-solving skills through extensive hands-on engineering experiments. A team consisting of an instructor, generally a PhD in Engineering, and a teaching fellow, generally a high school science teacher, closely work with students to pedagogically inculcate basics of core engineering disciplines such as civil, mechanical, electrical, materials, and chemical engineering. EI values independent problem-solving skills and simultaneously promote the team spirit among students. A number of crucial engineering aspects such as professional ethics, communications, technical writing, and understanding of common engineering principles are inculcated among high school students via well-designed individual and group activities. This paper discusses the model of EI program and its impact on students learning and their preparation for the engineering career.
ARTICLE | doi:10.20944/preprints201901.0008.v1
Subject: Engineering, Industrial & Manufacturing Engineering Keywords: food packaging; customization; product design; personalized design; reverse engineering; CAD; FDM
Online: 3 January 2019 (10:53:30 CET)
In the context of food packaging design, customization enhances the value of a product by meeting the needs of the consumer. Personalization is also linked to adaptation. This makes it possible to improve the properties of the packaging from various points of view: functional, aesthetic, economic and ecological. Currently the functional and formal properties of packaging are not investigated among themselves, however the study of both properties are the basis for creating a new concept of personalized and sustainable product. In accordance with this approach, the conceptual design procedure of packaging with personalized and adapted geometries based on the digitization of fresh food is proposed in this work. This study is based on the application of advanced technologies for the design and development of food packaging, in this case apples, in order to improve the quality of the packaging. The results obtained show that it is possible to use advanced technologies in the early stages of product design in order to obtain competitive products adapted to new emerging needs.
REVIEW | doi:10.20944/preprints201811.0590.v1
Subject: Biology, Physiology Keywords: 3D printing; Bioprinting; Additive Manufacturing, Tissue Engineering, Blood Vessels, Vascular Grafting
Online: 26 November 2018 (11:39:44 CET)
Abstract: The broad clinical use of synthetic vascular grafts for vascular diseases is limited by their thrombogenicity and low patency rate, especially for vessels with a diameter inferior to 6 mm. Alternatives such as tissue-engineered blood grafts (TEBGs) have gained increasing interest. Among the different manufacturing approaches, 3D bioprinting presents numerous advantages and enables the fabrication of multi-scale, multi-material, and multicellular tissues with heterogeneous and functional intrinsic structures. Extrusion-, inkjet- and light-based 3D printing techniques have been used for the fabrication of TEBG out of hydrogels, cells, and/or solid polymers. This review discusses the state-of-the-art research on the use of 3D printing for TEBG with a focus on the biomaterials and deposition methods.
REVIEW | doi:10.20944/preprints201808.0023.v1
Subject: Chemistry, Chemical Engineering Keywords: catalyst; direct synthesis; hydrogen peroxide; Pd based catalyst; reactor engineering; microreactor
Online: 1 August 2018 (14:10:48 CEST)
Hydrogen peroxide is an important chemical of increasing demand in today’s world. Currently, the anthraquinone autoxidation process dominates the industrial production of hydrogen peroxide. Herein, hydrogen and oxygen are reacted indirectly in the presence of quinones to yield hydrogen peroxide. Owing to the complexity and multi-step nature of the process, it is advantageous to replace the process with an easier and straightforward one. The direct synthesis of hydrogen peroxide from its constituent reagents is an effective and clean route to achieve this goal. Factors such as water formation due to thermodynamics, explosion risk, and the stability of the hydrogen peroxide produced hinder the applicability of this process at an industrial level. Currently, the catalysis for the direct synthesis reaction is palladium based and the research into finding an effective and active catalyst has been ongoing for more than a century now. Palladium in its pure form, or alloyed with certain metals are some of the new generation of catalysts that are extensively researched. Additionally, to prevent the decomposition of hydrogen peroxide to water, the process is stabilised by adding certain promoters such as mineral acids and halides. A major part of today’s research in this field focusses on the reactor and the mode of operation required for synthesising hydrogen peroxide. The emergence of microreactor technology has helped in setting up this synthesis in a continuous mode, which could possibly replace the anthraquinone process in the near future. This review will focus on the recent findings of the scientific community in terms of reaction engineering, catalyst and reactor design in the direct synthesis of hydrogen peroxide.
ARTICLE | doi:10.20944/preprints201807.0387.v1
Subject: Engineering, Biomedical & Chemical Engineering Keywords: membrane fouling; membrane plasticization; nutrients transport properties; perfusion bioreactors; tissue engineering
Online: 20 July 2018 (14:01:37 CEST)
High porosity and mass transport properties of microfiltration polymeric membranes benefits nutrients supply to cells when used as scaffolds in interstitial perfusion bioreactors for tissue engineering. High nutrients transport is assumed when pore size and porosity of the membrane are in the micrometric range. The present work demonstrates that the study of membrane fouling by proteins present in the culture medium, though not done usually, should be included in the routine testing of new polymer membranes for this intended application. Two poly(ε-caprolactone) microfiltration membranes presenting similar average pore size (~0.7µm) and porosity (>80%) but different external surface porosity and pore size have been selected as case study. The present work demonstrates that a membrane with lower surface pore abundance and smaller external pore size (~0.67 µm), combined with adequate hydrodynamics and tangential flow filtration mode is usually more convenient to guarantee high flux of nutrients. On the contrary, having large external pore size (~1.70µm) and surface porosity would incur in important internal protein fouling that could not been prevented with the operation mode and hydrodynamics of the perfusion system. Additionally, the use of glycerol in the drying protocols of the membranes might cause plasticization and a consequent reduction of mass transport properties due to membrane compaction by the pressure exerted to force perfusion. Therefore, preferentially, drying protocols that omit the use of plasticizing agents are recommended.
ARTICLE | doi:10.20944/preprints201801.0149.v1
Subject: Materials Science, Biomaterials Keywords: porous scaffold; collagen coating; bioactive peptide; skull defect repair; tissue engineering
Online: 17 January 2018 (06:48:17 CET)
The treatment of large-area bone defects remains a challenge; however, various strategies have been developed to improve the performances of scaffolds in bone tissue engineering. In this study, poly(lactide-co-glycolide)/hydroxyapatite (PLGA/HA) scaffold was coated with Asp-Gly-Glu-Ala (DGEA)-incorporated collagen for the repair of rat skull defect. Our results indicated that the mechanical strength and hydrophilicity of PLGA/HA scaffold were clearly improved and conducive to cell adhesion and proliferation. The collagen-coated scaffold with DGEA significantly promoted the repair of skull defect. These findings indicated that a combination of collagen coating and DGEA improved scaffold properties for bone regeneration, thereby providing a new potential strategy for scaffold design.
ARTICLE | doi:10.20944/preprints201801.0033.v1
Subject: Materials Science, Biomaterials Keywords: tissue engineering; lumen; stem cells, interstitial cells of Cajal; hydrogel scaffolds
Online: 5 January 2018 (09:36:18 CET)
Gastroparesis (GP) is associated with depletion of interstitial cells of Cajal (ICC) and enteric neurons, which leads to pyloric dysfunction followed by severe nausea, vomiting and delayed gastric-emptying. Regenerating these fundamental structures with stem cell therapy, would be helpful to restore gastric function in GP. Mesenchymal stem cells (MSC) have been successfully used in animal models of other gastrointestinal (GI) diseases including colitis. However, no study has been performed with these cells on GP animals. In this study, we explored if mouse MSC can be delivered from a hydrogel-scaffold to the luminal surfaces of GP mice stomach. Mouse MSC was seeded atop alginate-gelatin, coated with poly-L-lysine. These cell-gel constructs were placed atop stomach explants facing the luminal side. MSC grew uniformly all across the gel surface within 48 hr. When placed atop the lumen of the stomach, MSC migrated from the gels to the tissues as confirmed by positive staining with Vimentin and N-cadherin. The feasibility of transplanting a cell-gel construct to deliver stem cells in the stomach wall was successfully shown in a mice GP model, thereby making a significant advance towards envisioning the transplantation of an entire tissue-engineered ‘gastric patch’ or ‘microgels’ with stem cells, and growth factors.
ARTICLE | doi:10.20944/preprints201612.0100.v1
Subject: Earth Sciences, Environmental Sciences Keywords: engineering barriers; bentonite clays; thermochemical treatments; montmorillonite; structure modification; adsorption properties
Online: 19 December 2016 (11:08:23 CET)
The paper discusses the mechanism of montmorillonite structure alteration and bentonites properties modification (on the example of samples from clay deposit Taganka, Kazakhstan) due to the thermochemical treatment (treatment with inorganic acid solutions at different temperatures, concentrations and reaction times). With the use of the suit of methods certain processes were distinguished: transformation of montmorillonite structure, which appears in the leaching of interlayer and octahedral cations, protonation of the interlayer and OH groups at octahedral sheets. Changes in the structure of the 2:1 layer of montmorillonite and its interlayer result in significant changes in the properties – reduction of cation exchange capacity and an increase of specific surface area. The results of the work showed that bentonite clays retain a significant portion of its adsorption properties even after the long term and intense thermochemical treatment (6M HNO3, 60°C, 108 hours)