REVIEW | doi:10.20944/preprints202308.1283.v1
Subject: Chemistry And Materials Science, Electrochemistry Keywords: catalytic mechanism; edge engineering; defect engineering; phase engineering
Online: 17 August 2023 (11:48:21 CEST)
MoS2 has long been considered as a promising catalyst for hydrogen production. At present, there are many strategies to further improve its catalytic performance, such as edge engineering, defect engineering, phase engineering and so on. However, at present, there is still a great deal of controversy about the mechanism of MoS2 catalytic hydrogen production. For example, it is generally believed that the base plane of MoS2 is inert, but it has been reported that the inert base plane can undergo a transient phase transition in the catalytic process to play the catalytic role, which is contrary to the common understanding that the catalytic activity is only at the edge. Therefore, it is necessary to further understand the mechanism of MoS2 catalytic hydrogen production. In this article, we summarized the latest research progress on the catalytic hydrogen production of MoS2, which is of great significance for revisited the mechanism of MoS2 catalytic hydrogen production.
ARTICLE | doi:10.20944/preprints202309.1596.v1
Subject: Engineering, Electrical And Electronic Engineering Keywords: machine learning; construction industry; electrical engineering; electronics engineering
Online: 25 September 2023 (09:55:05 CEST)
The construction enterprise is a essential zone that contributes considerably to the worldwide financial system. but it faces numerous challenges, together with inefficiency in electric and electronics engineering tasks. This inefficiency results in delays, expanded charges, and decreased productivity. Device learning strategies have the capacity to deal with those challenges through optimizing the making plans and execution of electrical and electronics engineering tasks within the construction industry. This study paper targets to discover using machines gaining knowledge of strategies to maximise efficiency in electrical and electronics engineering projects inside the production industry. Mainly, the paper will be conscious of developing and imposing gadget mastering algorithms to optimize project scheduling, fabric procurement, and system utilization. The paper will even look at the ability of using predictive analytics to identify and mitigate dangers related to electric and electronics engineering tasks. The study could be based on a combination of literature review and empirical analysis. The literature evaluation will provide a top-level view of the demanding situations going through the development industry and the capability advantages of the usage of system getting to know strategies to deal with those challenges. The empirical evaluation will involve the improvement and testing of device mastering models on real-world information from electrical and electronics engineering initiatives inside the construction industry. The predicted results of this research are the development of a fixed of sensible recommendations for the use of machine gaining knowledge of strategies to optimize electric and electronics engineering projects within the construction industry. These suggestions will be beneficial for venture managers, engineers, and other stakeholders within the creation enterprise who're inquisitive about maximizing performance and decreasing charges of their tasks. Ordinary, this studies paper aims to contribute to the continued efforts to enhance the efficiency and productiveness of the development enterprise via exploring the ability of system studying techniques to optimize electrical and electronics engineering tasks.
SHORT NOTE | doi:10.20944/preprints202306.1656.v1
Subject: Engineering, Mechanical Engineering Keywords: engineering innovation; computer simulation; computational engineering; priori justification
Online: 23 June 2023 (10:44:26 CEST)
Computer simulation relies on well-defined experimental supported theories, models, and numerical methods. Computer simulation is an alternative to fill the gaps where the experiment is pricy or limited in engineering. Computer simulation is a high-fidelity computational technique that can work as an engineering innovation tool to try imaginative ideas beyond the available technologies. The accuracy of current computer simulation results is reliable enough to accelerate innovation for new materials and mechanical technologies without experimental validation. So, we may need to urge relying on computer simulation results without any experimental validation to accelerate engineering innovations. In addition, using high-fidelity computer simulation for engineering innovation acceleration without validation will be promoted if it is credited as a new classification. This subject and a related justification's classification in engineering have been discussed.
ARTICLE | doi:10.20944/preprints201802.0115.v1
Subject: Social Sciences, Education 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 And 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 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/preprints202303.0190.v1
Subject: Biology And Life Sciences, Ecology, Evolution, Behavior And Systematics Keywords: laccase; xenobiotics; protein engineering
Online: 10 March 2023 (09:10:48 CET)
Industrialization, intensive farming, rapid population growth and urbanization are the source of a large number of pollutants entering the environment. The current concentration of xenobiotics released into the environment exceeds its natural ability to decompose them. Enzymatic degradation of pollutants seems to be an environmentally friendly process. Due to the wide spectrum of substrate specificity, from inorganic compounds to high molecular weight organic compounds such as PAH or dyes, as well as favorable biochemical properties, laccase has been used in the biological removal of xenobiotics from the environment. It is important to understand the degradation mechanisms of pollutants and to evaluate the final products in terms of their toxicity. The laccase oxidizes the substrates with the simultaneous reduction of molecular oxygen to water, which is the purest reaction co-substrate. That is why it is called a green biocatalyst. The trend is an increase in the production of enzymes related to the intensive development of industry, bioremediation or synthetic chemistry. This leads to the search for laccases with greater activity and stability under extreme conditions. The potential of laccases to degrade xenobiotics can be promoted by improving enzymatic catalytic characterization using protein engineering and other genetic engineering methods.
REVIEW | doi:10.20944/preprints202010.0620.v1
Subject: Medicine And Pharmacology, Immunology And Allergy Keywords: Bioprinting; Bioinks; Tissue engineering
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
Subject: Chemistry And Materials Science, Organic Chemistry Keywords: hydrogels; tissue engineering; bioconjugation
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
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: chitosan; cardiac tissue engineering; scaffolds
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, Bioengineering 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.
ARTICLE | doi:10.20944/preprints202305.1202.v1
Subject: Engineering, Aerospace Engineering Keywords: Generative model; Knowledge-Based Engineering; Design automation; Conceptual design; Aerospace Engineering; Computer Aided Design
Online: 17 May 2023 (07:14:32 CEST)
This thesis presents the effects of work done on a software project for generative models and spreadsheets, allowing for a quick creation of the conceptual model of the aircraft. The subject of the work is a response to the current trends and needs prevailing in the field of computer design engineering CAD and aviation. In the initial chapters, theoretical issues related to the work being carried out were introduced and the methodology of creating software for construction and verification of the structure of aircraft along with the needs of interchange between databases of generative models was presented. In the next stages, the concepts and selected solutions for the user interface supporting the knowledge base were presented along with a set of procedures for its operation. Furthermore, the method of database integration with the methods of determining design features for the developed generative models and with the Siemens NX system. Furthermore, problems encountered in software development, as well as solution examples for model application are specified. The results obtained and the models generated on their basis were subjected to a strength analysis using Autodesk Inventor software and analysed in terms of meeting the initial assumptions. In the end, conclusions and observations resulting from the effects of the work presented in the project were formulated.
ARTICLE | doi:10.20944/preprints202211.0366.v1
Subject: Chemistry And Materials Science, Materials Science And Technology Keywords: Silk Fibroin; Sil-MA; 3D Printing; Additive Manufacturing; Tissue Engineering; Bioprinting; Bone Tissue Engineering
Online: 21 November 2022 (03:36:19 CET)
Methacrylated silk (Sil-MA) is a chemically modified silk fibroin specifically designed to be crosslinkable under UV light. This allows the structuring of this material throught additive manufacturing techniques and then to easily prototype patient specific construct. In this study we used Sil-MA to produce single layer crosslinked structures that can be withdrawal and ejected recovering their shape after rehydration. A complete chemical and physical characterization of the material has been conducted. Additionally, we tested the material biocompatibility according to the International Standard Organization protocols (ISO 10993) ensuring the possibility to use it in future trials. The material was also tested to verify its ability to support the osteogenesis. Two different additive manufacturing techniques have been tested (a Digital Light Processing (DLP) UV projector and a pneumatic extrusion technique) to develop Sil-MA grid. Finally, we provide a proof-of-concept that the printed Sil-MA structures are injectable.
REVIEW | doi:10.20944/preprints202306.0235.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: β-glucosidase; biocatalysis; biosynthesis; enzyme engineering
Online: 5 June 2023 (04:30:08 CEST)
β-glucosidases (BGLs) play a crucial role in the degradation of lignocellulosic biomass as well as in industrial applications such as pharmaceuticals, foods, and flavors. However, the application of BGLs has been largely hindered by issues such as low enzyme activity, product inhibition, low stability, etc. Many approaches have been developed to engineer BGLs to improve these enzymatic characteristics to facilitate industrial production. In this article, we review the recent advances in BGL engineering in the field, including the efforts from our laboratory. We summarize and discuss the BGL engineering studies according to the targeted functions as well as the specific strategies used for BGL engineering.
REVIEW | doi:10.20944/preprints202209.0132.v1
Subject: Medicine And Pharmacology, Obstetrics And 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: Biology And Life Sciences, Biochemistry And Molecular Biology 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: Computer Science And Mathematics, 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: Biology And Life Sciences, Biology And 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/preprints202308.0633.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: lipase; lid domain; protein engineering; rational design
Online: 8 August 2023 (08:30:15 CEST)
Lipases have tremendous potential for industrial use, particularly, those mostly active against water-insoluble substrates, such as triglycerides composed of long-chain fatty acids. However, in most cases, mutants often need to be constructed to achieve optimal performance for such substrates. Protein engineering techniques have been reported as strategies for improving lipase characteristics by introducing specific mutations in the cap domain of esterases or in the lid domain of lipases, or through lid domain swapping. Here, we have improved the lipase character of a lipase, retrieved from the Marine Metagenomics MarRef Database and assigned to the Actinoalloteichus genus (WP_075743487.1), through site-directed mutagenesis and by substituting its lid domain (FRGTEITQIKDWLTDA) by the one of Rhizopus delemar (previously Rhizopus oryzae) lipase (FRGTNSFRSAITDIVF). Results demonstrated that the redesigned mutants gain activity against bulkier triglycerides such as glyceryl tridecanoate and tridodecanoate, olive oil, coconut oil, and palm oil. The absence of a residue in the new lid, present in the original lid, appears to be a key aspect to the increase in lipase character, although full activity recovery is only obtained with lid swapping.
ARTICLE | doi:10.20944/preprints202308.0367.v1
Subject: Engineering, Bioengineering Keywords: cartilage; autologous chondrocyte implantation; tissue engineering; hydrogels
Online: 4 August 2023 (08:36:15 CEST)
Focal cartilage defects are a prevalent knee problem affecting people of all ages. Due to its avascular nature, cartilage has limited self-repair capacity, and osteochondral defects can lead to pain and long-term complications such as osteoarthritis. Autologous chondrocyte implantation (ACI) has been a successful surgical approach for repairing osteochondral defects over the past two decades. However, a major drawback of ACI is the de-differentiation of chondrocytes during their in vitro expansion. In this study, we isolated ovine chondrocytes and cultured them in a two-dimensional environment as for ACI procedures. We hypothesised that the 3D scaffolds would support the cells re-differentiation without the need for growth factors and so we encapsulated them into soft collagen and alginate (col/alg) hydrogels. Chondrocytes embedded into hydrogels were viable and proliferated. After 7 days they acquired a rounded morphology and started to aggregate. Gene expression studies showed that the genes associated with chondrogenesis started to be up regulated as early as day one. At 21 days chondrocytes had extensively colonized the hydrogel, forming large cell clusters and started to deposit collagen II and aggrecan with limited collagen type I deposition. These findings highlight the potential of soft col/alg hydrogels to enhance ACI outcomes by creating a favourable microenvironment for chondrocyte reprogramming and re-differentiation, eliminating the dependency on growth factors.
ARTICLE | doi:10.20944/preprints202307.0236.v1
Subject: Medicine And Pharmacology, Medicine And Pharmacology Keywords: fibroblasts; endothelial cell; differentiation; tissue engineering; matrigel
Online: 5 July 2023 (08:38:25 CEST)
The role of mesenchymal-to-endothelial transition in the angiogenic response is controversial. Toward this, the present study aimed to determine if fibroblasts contribute to angiogenesis. Endothelial differentiation of fibroblasts was induced by culturing MRC-5 cells (human fetal lung fibroblast cells) on top of Matrigel hydrogel or embedded inside the hydrogel. The formation of ca-pillary-like networks in response to angiogenic signals was observed. The tube formation occurs quickly and can be visualized us-ing a phase-contrast inverted microscope, and/or the cells can be treated with DAPI before the assay and tubes can be visualized through fluorescence or confocal microscopy. Furthermore, fibroblasts cultured in a higher concentration invaded the Matrigel hydrogel and formed stem-cell-like spheroids. These spheroids embedded in matrigel matrices of varying densities sprouted to form 3D connective-tissue networks. Collectively, our results highlight the endothelial differentiation capacity of human lung fibroblasts. The results obtained in this work may have an impact on the search for alternative cell sources for vascular tissue engineering and the overcome of obstacles to vascularization of autologous tissue-engineered constructs and the production of functional grafts for clinical use.
ARTICLE | doi:10.20944/preprints202305.1722.v1
Subject: Engineering, Other Keywords: Research impact; engineering; Mexico; article citation analysis
Online: 25 May 2023 (03:11:55 CEST)
Engineers make things, make things work, and make things work better and easier. This kind of knowledge is crucial for innovation, and much of the explicit knowledge developed by engineers is embodied in scientific publications. In this paper, we analyze the evolution of publications and citations in Engineering in a middle-income country such as Mexico. Using a database of all Mexican publications in Web of Science from 2004 to 2017, we explore the characteristics of publications that tend to have the greatest impact; this is the highest number of citations. Among the variables studied are the type of collaboration (no collaboration, domestic, bilateral, or multilateral), the number of coauthors and countries, the language of the article, controlling for a coauthor from the USA and the affiliation institution of the Mexican author(s). Our results emphasize the overall importance of joint international efforts and suggest that publications with the highest number of citations are those with multinational collaboration (coauthors from three or more countries), written in English, and when one of the coauthors is from the USA.
REVIEW | doi:10.20944/preprints202305.1531.v1
Subject: Chemistry And Materials Science, Biomaterials Keywords: Biomaterials; Hybrid Materials; Tissue Engineering; Regenerative Medicine
Online: 22 May 2023 (16:19:46 CEST)
The main purpose of tissue engineering is to fabricate and exploit engineered constructs suitable for the effective replacement of damaged tissues and organs, and able to perfectly integrate with the host’s organism without eliciting any adverse reaction. Ideally, autologous materials represent the best option, but they are often limited due to the low availability of compatible healthy tissues. So far, one therapeutic approach relies on the exploitation of synthetic materials: they exhibit good features in terms of impermeability, deformability and flexibility, but present chronic risks of infections and inflammations. Alternatively, biological materials, including naturally derived ones and acellular tissue matrices of human or animal origin, can be used to induce cells growth and differentiation, which are needed for tissue regeneration: however, this kind of materials lacks satisfactory mechanical resistance and reproducibility, affecting their clinical application. In order to overcome the above-mentioned limitations, hybrid materials, which can be obtained by coupling synthetic polymers and biological materials, have been investigated with the aim to improve biological compatibility and mechanical features. Currently, the interest in these mate-rials is growing, but the ideal ones have not been found yet. The present review aims at exploring some applications of hybrid materials, with particular mention to urological and cardiovascular fields: in the first case, the efforts to find a construct that can guarantee impermeability, mechanical resistance and patency will be herein illustrated; in the second case, the search for impermeability, hemocompatibility and adequate compliance will be been disclosed.
ARTICLE | doi:10.20944/preprints202305.1473.v1
Subject: Engineering, Bioengineering Keywords: Decellularization; heart valve; tissue engineering; xenograft; biomaterial
Online: 22 May 2023 (08:26:48 CEST)
In order to overcome the disadvantages of existing treatments in heart valve tissue engineering, decellularization studies are carried out. The main purpose of decellularization is to eliminate the immunogenicity of biologically derived grafts and to obtain a scaffold that allows recellularization while preserving the natural tissue architecture. SD and SDS are detergent derivatives frequently used in decellularization studies. The aim of our study is to decellularize the pulmonary heart valves of young Merino sheep by using low-density SDS and SD detergents together, and then to perform their detailed characterization to determine whether they are suitable for clinical studies. Pulmonary heart valves of 4-6 month old sheep were decellularized in detergent solution for 24 hours. The amount of residual DNA was measured to determine the efficiency of decellularization. Then, the effect of decellularization on the ECM by histological staining was examined. In addition, the samples were visualized by SEM to determine the surface morphologies of the scaffolds. Uniaxial tensile test was performed to examine the effect of decellularization on biomechanical properties. The results showed DNA removal of 94% and 98% from the decellularized leaflet and artery portions after decellularization relative to the control group. No cell nuclei were found in histological staining and it was observed that the 3-layer leaflet structure was preserved. As a result of the tensile test, it was determined that there was no statistically significant difference between the control and decellularized groups in the UTS and elasticity modulus, and the biomechanical properties did not change. In conclusion, we suggest that the pulmonary valves of decellularized young Merino sheep can be used as a initial matrix in heart valve tissue engineering studies.
REVIEW | doi:10.20944/preprints202305.0771.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Antimicrobial Resistance; Phage engineering; endolysins; phage therapy
Online: 10 May 2023 (15:11:24 CEST)
Antimicrobial resistance (AMR) is a major global concern; antibiotics and other regular treatment methods have failed to overcome the increasing number of infectious diseases. Bacteriophages (phages) are viruses that specifically target/ kill bacterial hosts without affecting other human microbiome. Phage therapy provides optimism in the current global healthcare scenario with a long history of its applications in humans that has now reached various clinical trials. Phages in clinical trials have specific requirements of being exclusively lytic, free from toxic genes with an enhanced host range that adds an advantage to this requisite. This review explains in detail the various phage engineering methods and their potential applications in therapy. To make phages more efficient, engineering has been attempted using techniques like conventional homologous recombination, Bacteriophage Recombineering of Electroporated DNA (BRED), clustered regularly interspaced short palindromic repeats (CRISPR)-Cas, CRISPY-BRED/Bacteriophage Recombineering with Infectious Particles (BRIP), chemically accelerated viral evolution (CAVE), and phage genome rebooting. Phages are administered in cocktail form in combination with antibiotics, vaccines, and purified proteins, such as endolysins. Thus, phage therapy is proving to be a better alternative for treating life-threatening infections, with more specificity and fewer detrimental consequences.
ARTICLE | doi:10.20944/preprints202212.0439.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: Yarrowia; pheromone; desaturase; Manduca; conjugase; metabolic engineering
Online: 23 December 2022 (03:50:22 CET)
One of the most interesting groups of fatty acid derivates is the group of conjugated fatty acids, from which the most researched are conjugated linoleic acid (CLA) and conjugated linolenic acid (CLNA), which are associated with countless health benefits. Sex pheromone mixture of some insect species, including tobacco horn-worm (Manduca sexta), are typical for the production of uncommon C16 long conjugated fatty acids with two and three conjugated double bonds, as opposed to C18 long CLA and CLNA. In this study, M. sexta desaturases MsexD2 and MsexD3 were expressed in multiple strains of Y. lipolytica with different genotypes. Experiments with supplementation of fatty acid methyl esters into the medium resulted in production of novel fatty acids. Using GCxGC-MS 20 new fatty acids with two or three double bonds were identified. Fatty acids with conjugated or isolated double bonds or combination of both were produced in trace amounts. Results of this study prove that Y. lipolytica is capable of synthesizing C16 conjugated fatty acids. Further genetic optimization of the Y. lipolytica genome and optimization of the fermentation process could lead to increased production of novel fatty acid derivatives with biotechnologically interesting properties.
REVIEW | doi:10.20944/preprints202212.0115.v1
Subject: Chemistry And Materials Science, Biomaterials Keywords: bioactive glass; gelatin; tissue engineering; bone; composite
Online: 7 December 2022 (04:30:39 CET)
Nano/micron-sized bioactive glass (BG) particles are attractive candidates for both soft and hard tissue engineering. They can chemically bond to the host tissues, enhance new tissue formation, activate cell proliferation, stimulate the genetic expression of proteins, and trigger unique an-ti-bacterial, anti-inflammatory, and anti-cancer functionalities. Recently, composites based on bi-opolymers and BG particles have been developed with various state-of-the-art techniques for tis-sue engineering. Gelatin, a semi-synthetic biopolymer, has attracted the attention of researchers because it is derived from the most abundant protein in the body, viz., collagen. It is a polymer that can be dissolved in water and processed to acquire different configurations, such as hydro-gels, fibers, films, scaffolds, etc. Searching "bioactive glass gelatin" in the tile on Scopus renders 80 highly relevant articles published in the last ~10 years, which signifies the importance of such composites. First, this review addresses the basic concepts of soft and hard tissue engineering, in-cluding the healing mechanisms and limitations ahead. Then, current knowledge on gelatin/BG composites including composition, processing and properties is summarized and discussed both for soft and hard tissue applications. This review explores physical, chemical and mechanical features and ion-release effects of such composites concerning osteogenic and angiogenic respons-es in vivo and in vitro. Additionally, recent developments of BG/gelatin composites using 3D/4D printing for tissue engineering are presented. Finally, the perspectives and current challenges in developing desirable composites for the regeneration of different tissues are outlined.
ARTICLE | doi:10.20944/preprints202212.0074.v1
Subject: Biology And Life Sciences, Anatomy And Physiology Keywords: tissue engineering; bone; laser; femtosecond; patterning; direct
Online: 5 December 2022 (10:26:46 CET)
Laser patterning of implant materials for bone tissue engineering purposes has shown to be a promising technique to control cell properties such as adhesion or differentiation, resulting in an enhanced osteointegration. However, the perspective of patterning the bone tissue side interface to generate microstructure effects has never been investigated. In the present study, three different laser-generated patterns were machined on the bone surface with the aim to identify the best surface morphology compatible with osteogenic-related cells recolonization. The laser patterned bone tissue was characterized by electron scanning microscopy and confocal microscopy in order to obtain a comprehensive picture of the bone surface morphology. Cortical bone patterning impact upon cell compatibility and cytoskeleton rearrangement to the patterned surfaces was performed with Stromal Cells from Apical Papilla (SCAPs). Results indicated that laser machining had no detrimental effect upon consecutively seeded cells metabolism. Orientation assays revealed that surface patterning characterized by larger hatch distances was correlated with a higher cell cytoskeletal conformation to the laser-machined patterns. For the first time, to our knowledge, bone is considered and assessed here as a potentially engineered-improvable biological interface. Further studies shall focus on in vivo implications of this direct patterning.
ARTICLE | doi:10.20944/preprints202211.0351.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: enzyme-constrained model; Bacillus subtilis; metabolic engineering
Online: 18 November 2022 (07:09:22 CET)
Genome-scale metabolic models (GEMs) play an important role in the phenotype prediction of microorganisms, and their accuracy can be further improved by integrating other types of biological data such as enzyme concentrations and kinetic coefficients. Enzyme-constrained models (ecModels) have been constructed for several species and were successfully applied to increase the production of commodity chemicals. However, there was still no genome-scale ecModel for the important model organism Bacillus subtilis prior to this study. Here, we integrated enzyme kinetic and proteomic data to construct the first genome-scale ecModel of B. subtilis (ecBSU1) using the ECMpy workflow. We first used ecBSU1 to simulate overflow metabolism and explore the trade-off between biomass yield and enzyme usage efficiency. Then, we simulated the growth rate on eight previously published substrates and found that the simulation results of ecBSU1 were in good agreement with the literature. Finally, we identified target genes that enhance the yield of commodity chemicals using ecBSU1, most of which were consistent with the experimental data, and some of which may be potential novel targets for metabolic engineering. This work demonstrates that the integration of enzymatic constraints is an effective method to improve the performance of GEMs. The ecModel can predict overflow metabolism more precisely and can be used for the identification of target genes to guide the rational design of microbial cell factories.
ARTICLE | doi:10.20944/preprints202210.0192.v1
Subject: Computer Science And Mathematics, Analysis Keywords: Knowledge-based Systems; Ontology; Knowledge Engineering; MCDA.
Online: 13 October 2022 (09:54:49 CEST)
Decision making as a result of system dynamics analysis requires, in practice, a straightforward and systematic modelling capability as well as a high-level of customisation and flexibility to adapt to situations and environments that may vary very much from each other. While in general terms a completely generic approach could be not as effective as ad-hoc solutions, the proper application of modern technology may facilitate agile strategies as a result of a smart combination of qualitative and quantitative aspects. In order to address such a complexity, we propose a knowledge-based approach that integrates the systematic computation of heterogeneous criteria with open semantics. The holistic understanding of the framework is described by a reference architecture and the proof-of-concept prototype developed can support high-level system analysis, as well as it suitable within a number of applications contexts - i.e. as a research/educational tool, communication framework, gamification and participatory modelling. Additionally, the knowledge-based philosophy, developed upon Semantic Web technology, increases the capability in terms of holistic knowledge building and re-use via interoperability. Last but not least, the framework is designed to constantly evolve in the next future, for instance by incorporating more advanced AI-powered features.
ARTICLE | doi:10.20944/preprints202209.0019.v1
Subject: Biology And Life Sciences, Endocrinology And Metabolism 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 And 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: Computer Science And Mathematics, 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 And Pharmacology, Immunology And Allergy 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
Subject: Physical Sciences, Fluids And Plasmas Physics Keywords: practical engineering education; fluid mechanics; pedagogy; laboratories
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
Subject: Social Sciences, Education Keywords: practical engineering education; remote practicals; blended learning
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, Control And Systems Engineering 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: Chemistry And Materials Science, Materials Science And Technology 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: Engineering, Bioengineering 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: Environmental And Earth Sciences, Water Science And Technology 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.
Subject: Computer Science And Mathematics, Artificial Intelligence And Machine Learning Keywords: ChatGPT; Artificial intelligence; chatbot; Open AI; Digital engineering.
Online: 16 August 2023 (09:59:35 CEST)
Herein are reported the main pros and cons of using the conversational Artificial Intelligence (AI) called “ChatGPT” as a tool to write essays in the academic and scientific community. Also, selected mathematical and scientific problems were solved to determine the effectiveness of this platform. To this end, a systematic case study was designed and conducted to obtain data generated by the chatbot that was further analyzed. Six different topics were chosen for the essay evaluation, and the introduction section was created using this AI. Meanwhile, six mathematical problems related to integrals, z-transform, Laplace transform, and resolution of ordinary differential equations were solved. Furthermore, a scientific problem associated with the structural properties of material was also solved. After data analysis, we concluded that the conversational platform could quickly create written essays with well-structured words. Nonetheless, in almost all cases, the chatbot only used basic information to complete the introduction, and no critical writing was obtained. For the mathematical case study, we observed that under the current status of the ChatGPT, this platform has no ability or skills to solve complex equations. Thus, significant changes need to be conducted to improve the performance of ChatGPT for mathematical solutions.
ARTICLE | doi:10.20944/preprints202307.1769.v1
Subject: Biology And Life Sciences, Life Sciences Keywords: mesenchymal stem cells; proteomics; tissue engineering; regenerative medicine
Online: 26 July 2023 (07:06:41 CEST)
Mesenchymal stem cells (MSCs) are an attractive therapeutic tool for tissue engineering and regenerative medicine owing to their regenerative and trophic properties. The best-known and most widely used are bone marrow MSCs which are currently being harvested and developed from a wide range of adult and perinatal tissues. MSCs from different sources are believed to have different secretion potentials and production which may influence their therapeutic effects. To confirm it, we performed a quantitative proteomic analysis based on the TMT technique of MSCs from three different sources: Wharton’s jelly (WJ), dental pulp (DP) and bone marrow (BM). Our analysis focused on MSC biological properties of interest for tissue engineering. We identified a total of 611 differentially expressed human proteins. WJ-MSCs showed the greatest variation compared with the other sources. WJ produced more extracellular matrix (ECM) proteins and ECM-affiliated proteins and appeared more able to modulate the inflammatory and immune response. BM-MSCs displayed enhanced differentiation and paracrine communication capabilities. DP-MSC appeared to promote exosome production. The results obtained confirm the existence of differences between WJ, DP and BM-MSC and the need to select the MSC origin according to the therapeutic objective sought.
ARTICLE | doi:10.20944/preprints202306.1890.v1
Subject: Engineering, Other Keywords: Social Equity; Residential Energy Modeling; Digital Twins; Engineering
Online: 28 June 2023 (05:40:20 CEST)
This research examines the impact of social equity on energy consumption. We constructed a digital twin for residential energy consumption by enriching the synthetic population with real-world surveys and feeding them with other environmental and appliance data to the energy modeling framework. We analyzed household hourly energy consumption data from Albemarle County and Charlottesville City in Virginia, USA, for the year 2019. We used clustering analysis to identify patterns in social equity and energy consumption. The results demonstrated the impact of different residential attributes on energy poverty. Statistical analyses, including ANOVA and Chi-Squared tests, were conducted to test for significant differences between racial groups in quantitative and categorical variables. The study found that race is significant in determining the location and quality of housing. People of color often live in areas with higher pollution and less access to green spaces. Additionally, income levels and the age of the house are influential factors in determining energy efficiency. Future work should focus on collecting and analyzing data at the country level and using qualitative data collection methods to gain a more comprehensive understanding of social equity issues concerning energy consumption. Overall, this study provides valuable insights into the relationship between different residential attributes and energy consumption, which can inform policy development to promote more equitable and sustainable communities.
ARTICLE | doi:10.20944/preprints202306.1914.v1
Subject: Engineering, Industrial And Manufacturing Engineering Keywords: Additive Manufacturing; Tissue Engineering; DLP; Graphene Oxide; PLLA
Online: 27 June 2023 (13:03:50 CEST)
In this study, 3D printing of poly-l-lactic acid (PLLA) scaffolds reinforced with graphene oxide (GO) nanoparticles via Digital Light Processing (DLP) was investigated to mimic bone tissue. Stereolithography is one of the most accurate additive manufacturing method, but the dominant available materials used in this method are toxic. In this research, a biocompatible resin (PLLA) was synthetized and functionalized to serve the purpose. Due to the low mechanical properties of the printed product with the neat resin, graphene oxide nanoparticles in three levels (0.5, 1, and 1.5 Wt.%) were added with the aim of enhancing the mechanical properties. At first, the optimum post cure time of the neat resin was investigated. Consequently, all the parts were post-cured for three hours after printing. Due to the temperature-dependent structure of GO, all samples were placed in an oven at 85 ° C for different time periods of 0, 6, 12, and 18 hours to increase mechanical properties. The compression test of heat treated samples reveals that the compressive strength of the printed parts containing 0.5,1, and 1.5 % of GO increased by 151,162 ad 235%, respectively. Scaffolds with the designed pore sizes of 750 microns and a porosity of 40% were printed. Surface hydrophilicity test was performed for all samples showing that the hydrophilicity of the samples increased with increasing GO percentage. The degradation behavior of the samples was evaluated in a PBS environment, and it revealed that by increasing GO, the rate of component degradation increased, but the heat treatment had the opposite effect and decreased the degradation rate. Finally, besides improving biological properties, a significant increase in mechanical properties under compression can introduce the printed scaffolds as a suitable option for bone implants.
ARTICLE | doi:10.20944/preprints202304.1146.v1
Subject: Computer Science And Mathematics, Other Keywords: Human Robot Interaction; Cognition; Emotion; Animacy; Affective Engineering
Online: 28 April 2023 (08:30:10 CEST)
It is known that people perceive animacy in objects. However, many studies on animacy and emotional expressions are limited in that the investigated motions were created by experimenters themselves. This makes the objective validity unclear. Moreover, it remains unclear what types of movements can express emotions with animacy due to the limited number of investigations examining both animacy and emotional expressions. Therefore, we investigated the motion elements for both animacy perception and emotional expressions using simple objects that lack features of specific living things, such as eyes, ears, tails, and voices in this study. First, we investigated the motion elements for animacy perception and emotional expressions using a robot simulator that enabled participants to create undulatory motions by tuning parameters for speed, height, and randomness. In total, 64 participants created motions in Normal (neutral), Joy, Sad, Relaxed, and Angry conditions. The results showed that the medians of speed and height in Normal, related only to animacy, were 0.5569[Hz] and 3.050cm at the edges/4.575cm at the center. The differences in Joy were 0.4028[Hz] and 3.348cm/5.022cm, in Sad were −0.1652[Hz] and −0.9982cm/−1.497cm, in Relaxed were −0.1979[Hz] and −0.4902cm/−0.7353cm, and in Angry were 0.5212[Hz] and 4.688cm/7.032cm. Second, we investigated whether the motion elements revealed in the first experiment were sufficient to express emotions with animacy, using a robot simulator that reflected the results of the motion element investigation. In total, 44 online participants observed the simulator. The results showed that participants could understand emotional arousal levels at the same time as animacy, but they did not fully understand emotional valence. Our findings provide design guidelines for robots that exhibit emotional expressions and closely interact with humans.
REVIEW | doi:10.20944/preprints202304.0628.v1
Subject: Medicine And Pharmacology, Medicine And Pharmacology Keywords: 3D bioprinting; hydrogel; bioink; tissue engineering; bionic scaffold
Online: 20 April 2023 (08:00:19 CEST)
Regeneration of biological tissues in medicine is challenging, and 3D bioprinting offers an innovative way to create functional multicellular tissues. One common way in bioprinting is bioink which is one type of the cell-loaded hydrogel. For clinical application, however, the bioprinting still suffers from satisfactory performance, e.g. in vascularization, effective antibacterial, immunomodulation and regulation of collagen deposition. Many studies have incorporated different bioactive materials into the 3D printed scaffolds to optimize the bioprinting. Here, we review a variety of additives added to the 3D bioprinting hydrogel. The underlying mechanisms and methodology for biological regeneration are important and will provide useful basis for future research.
REVIEW | doi:10.20944/preprints202211.0106.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: Keywords: chloroplast genetic engineering; Homologus recombination; ORF; photosynthesis
Online: 7 November 2022 (04:31:29 CET)
Abstract: Chloroplast is a new hotspot in the field of plant transformation system of plant genetic engineering. Initially developed in Chlamydomonas and tobacco, it is now feasible in a broad range of species. They exploit the homologous recombination and segregation pathways acting on chloroplast genomes and are based on direct repeats, transient co-integration or co-transformation and segregation of trait and marker genes. Foreign site-specific recombinases and their target sites provide an alternative and effective method for removing marker genes from plastids.Chloroplast genetic engineering has many advantages over nuclear genetic enginering, especially site-specific introduction of foreign genes ,leading to the absence of gene siliency and positon effect,which providing the available to explore the regulation and mechanism of chloroplast genes`expression in vitro .It also can identify the structure and function of the chloroplast genome , the expression of chloroplast affect the nulear genome. In this paper, the basic methodology of chloroplast transformation, the current techniques and applications, and the future possibilities for Chloroplast genetic engineering was reviewed[1-3].
ARTICLE | doi:10.20944/preprints202207.0054.v1
Subject: Computer Science And Mathematics, Security Systems 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: Chemistry And 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 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: Chemistry And 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: Biology And Life Sciences, Biochemistry And Molecular Biology 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: Chemistry And 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: Biology And Life Sciences, Biochemistry And Molecular Biology 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 And Materials Science, 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: Computer Science And Mathematics, Information Systems 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: Business, Economics And Management, Accounting And Taxation 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 And Photonics 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: Biology And Life Sciences, Cell And 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: Biology And Life Sciences, Cell And Developmental Biology 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: Biology And Life Sciences, Immunology And Microbiology 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.
REVIEW | doi:10.20944/preprints202309.0901.v1
Subject: Chemistry And Materials Science, Materials Science And Technology Keywords: hydrogel; natural polymer; drug delivery; tissue engineering; wound healing
Online: 14 September 2023 (04:39:02 CEST)
Hydrogels prepared from natural polymer have attracted extensive attentions in biomedical fields such as drug delivery, wound healing, and regenerative medicine due to their good biocompatibility, degradability and flexibility. This review outlines the commonly used natural polymer in hydrogel preparation, including cellulose, chitosan, collagen/gelatin, alginate, hyaluronic acid and starch. The polymeric structure and process/synthesis of natural polymers are illustrated, and natural polymer-based hydrogels including the hydrogel formation and properties are elaborated. Subsequently, the biomedical application of hydrogels based on natural polymer in drug delivery, tissue regeneration, wound healing and other biomedical field is summarized. Finally, the future perspectives of natural polymers and hydrogels based on them are discussed. For natural polymer, novel technologies such as enzymatic and biological methods are developed to improve the structural properties and the development of new natural based polymers or natural polymer derivatives with high performance is still very important and challenging. For natural polymer-based hydrogels, novel hydrogel materials, like double-network hydrogel, multifunctional composite hydrogels and hydrogel microrobots are designed to meet the advanced requirements in biomedical application, and new strategies such as dual-crosslinking, microfluidic chip, micropatterning and 3D/4D bioprinting, have been explored to fabricate advanced hydrogel materials with designed properties for biomedical application. Overall, natural polymeric hydrogels have attracted increasing interests in biomedical application, and the development of novel natural polymer-based materials and new strategies/methods for hydrogel fabrication is badly desirable and still challenging.
REVIEW | doi:10.20944/preprints202308.1403.v1
Subject: Engineering, Aerospace Engineering Keywords: aerospace coatings; bio-inspired coatings; polymer coatings; surface engineering
Online: 21 August 2023 (09:47:41 CEST)
The aerospace industry demands high-performance materials that can withstand extreme conditions and maintain efficiency in a variety of applications. Bio-inspired polymer coatings have emerged as a promising approach to meet these demands, by drawing inspiration from natural systems to develop new coatings that exhibit enhanced properties, such as self-cleaning, anti-icing, thermal management, and corrosion resistance. In this review, recent developments in the field of bio-inspired polymer coatings for aerospace applications are presented, covering a range of coatings and their respective properties. We discuss the recent developments and applications of bio-inspired coatings, with a focus on their advantages and challenges in aerospace applications. We also highlight the potential for future research and development in this field, including the integration of advanced technologies such as nanotechnology and additive manufacturing. The review aims to provide insights into the current state-of-the-art of bio-inspired polymer coatings for aerospace applications and to inspire further research in this rapidly growing field.
ARTICLE | doi:10.20944/preprints202308.0745.v1
Subject: Chemistry And Materials Science, Biomaterials Keywords: Tissue engineering; regenerative medicine; hydrogels; GelMA; alginate; platelet lysate
Online: 9 August 2023 (10:58:51 CEST)
Hydrogels (gels) are attractive tools for tissue engineering and regenerative medicine due to their potential for drug delivery and ECM-like composition. In this study, we use rheology to characterize GelMA/alginate gels loaded with human platelet lysate (PL). We then characterize these gels from a physicochemical perspective and evaluate their ability to transport PL proteins, their pore size, and their rate of degradation. Finally, their biocompatibility is evaluated. We describe how alginate changes the mechanical behavior of the gels from elastic to viscoelastic after ionic (calcium-mediated) crosslinking. In addition, we positively report the release of PL proteins and relate it to the degradation profile of the gels and the biocompatibility of the gels. Thus, the developed gels represent attractive substrates for both cell studies and bioactive materials.
ARTICLE | doi:10.20944/preprints202306.2020.v1
Subject: Chemistry And Materials Science, Biomaterials Keywords: Bioresponsive; gelatin; hyaluronic acid; bioprinting; cell-delivery; tissue engineering
Online: 29 June 2023 (02:20:28 CEST)
Development of bioresponsive extrudable hydrogels for 3D bioprinting is imperative to address the growing demand for scaffold design and efficient and reliable methods of tissue engineering and regenerative medicine. This study proposed genipin-crosslinked gelatin-hyaluronic acid hydrogel bioink with different amounts of gelatin tailored for 3D bioprinting, focusing on high cell density loading and less artificial extra-cellular matrix (ECM) effect, as well as exploring their potential applications in tissue engineering. The bioresponsiveness of these hydrogel scaffolds was successfully evaluated in different physiological conditions. 3D and four-axis printing of complex structures such as shapes of hollow tube, star, pyramid, and four-axis tubular scaffolds prove the hydrogel’s high extrusion ability and post-printing shape fidelity. Cytocompatibility and high cell density 3D bioprinting using this moderately stable hydrogel exhibit high potential for precise cell-delivery modes in tissue engineering as well as regenerative medicine.
REVIEW | doi:10.20944/preprints202306.0565.v1
Subject: Engineering, Chemical Engineering Keywords: Engineering design; Landscape design; Underground sewage treatment environmental pollutions.
Online: 8 June 2023 (02:00:26 CEST)
The applicable conditions and scope of the underground sewage treatment plant include small amount of sewage, less available land on the ground, special requirements for the above-ground landscape, low groundwater level, easy-to-excavate geology, and the buried depth of the sewage return pipe is not very large. It is not under the main road, has certain distance from residential buildings, is not a depression and does not accumulate rainwater, and the sewage discharge requirements are not very strict. The underground sewage treatment plants are suitable in an area, where thermal insulation needs to be considered, less requisitionable land area, and higher environmental requirements The results of underground landscape design study showed that the design of principles, features, styles, water ecologies, combination between community and ecological friendly, operation and maintenance cost of the underground landscape should be emphasized. The construction of ecological complex will lead the sewage treatment plant exchange from minus assets to the ecological positive assets, which will meet the needs of future urban social economic development and environmental protection. The results of development direction exploration study showed that innovation on design concept, breakthroughs of key sewage treatment technology and variation of investment and operation mode can reduce the land occupation investment and operation cost, and the underground sewage plant with large scale and semi-underground mode owes broader prospects for development.
ARTICLE | doi:10.20944/preprints202305.1829.v1
Subject: Engineering, Industrial And Manufacturing Engineering Keywords: Poka Yoke; Pick to Lights; architecture; effectiveness; industrial engineering
Online: 26 May 2023 (03:43:43 CEST)
Product assembly is usually one of the last steps in the entire production process. This activity is typically entrusted to assembly workers because it is generally not possible to automate every type of product. For complex products, assembly can take a long time until the fitter learns the procedure and is able to assemble the product on his own. This contribution presents a cus-tom-developed system that enables controlled assembly of the extruder and can be used for complex and diverse products. The system serves to guide the fitter precisely and shows him which part to use at which time. The proposed system will show and describe on the display all necessary assembly steps and parts. Two-step verification is used to ensure that the correct part is picked from the stack. The contribution is supported by the implementation of a case study in a small company with a sample of 30 employees, which demonstrates that the proposed system shortens the extruder assembly time and significantly reduces the error rate. The presented solution is scalable and flexible, as it can be easily adapted to display the assembly steps of another product.
REVIEW | doi:10.20944/preprints202305.1232.v1
Subject: Engineering, Bioengineering Keywords: tissue engineering; 3D bioprinting; natural-derived hydrogel; hydrogel crosslinking
Online: 17 May 2023 (10:36:59 CEST)
3D bioprinting is the process of manipulating cell-laden bioinks to fabricate living structures. 3D bioprinting techniques have brought considerable innovation in biomedicine, especially in the field of tissue engineering, allowing the production of 3D organ and tissue models for in vivo transplantation purposes or for in-depth and precise in vitro analyses. Natural-derived hydrogels, especially those obtained from the decellularization of biological tissues, are promising bioinks for 3D printing purposes, as they present the best biocompatibility characteristics. Despite this, many natural hydrogels do not possess the necessary mechanical properties to allow a simple and immediate application in the 3D printing process. In this review, we focus on the bioactive and mechanical characteristics that natural hydrogels may possess to allow efficient production of organs and tissues for biomedical applications, emphasizing the reinforcement techniques to improve their biomechanical properties.
ARTICLE | doi:10.20944/preprints202304.0524.v1
Subject: Engineering, Automotive Engineering Keywords: Camera; Radar; Lidar; Automotive Engineering; Adverse Weather; Sensor Perception
Online: 18 April 2023 (12:40:48 CEST)
Vehicle safety promises to be one of the Advanced Driver Assistance System (ADAS) biggest benefits. Higher levels of automation remove the human driver from the chain of events that can lead to a crash. Sensors play an influential role in vehicle driving as well as in ADAS by helping the driver to watch the vehicle’s surroundings for safe driving. Thus, the driving load is drastically reduced from steering as well as accelerating and braking for long-term driving. The baseline for the development of future intelligent vehicles relies even more on the fusion of data from surrounding sensors such as Camera, Lidar and Radar. These sensors not only need to perceive in clear weather but also need to detect accurately adverse weather and illumination conditions. Otherwise, a small error could have an incalculable impact on ADAS. As most of the current study is based on indoor or static testing. In order to solve this problem, this paper designs a series of dynamic test cases with the help of outdoor rain and intelligent lightning simulation facilities to make the sensor application scenarios more realistic. As a result, the effect of rainfall and illumination on sensor perception performance is investigated. As speculated, the performance of all automotive sensors is degraded by adverse environmental factors, but their behaviour is not identical. Future work on sensor model development and sensor information fusion should therefore take this into account.
REVIEW | doi:10.20944/preprints202304.0315.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: Nicotiana, alkaloids, anti-tumor, metabolic engineering, de-novo synthesis
Online: 13 April 2023 (08:53:23 CEST)
Alkaloids are the most diversified nitrogen-containing secondary metabolites having antioxi-dant, and antimicrobial properties and are extensively used in pharmaceuticals to treat different types of cancer. Nicotiana serves as a reservoir of anticancer alkaloids and is also used as a model plant for the de novo synthesis of various anti-cancer molecules through genetic engineering. Up to 4% of the total dry weight of Nicotiana was found to be composed of alkaloids where nicotine, nornicotine, anatabine, and anabasine are reported as the dominant alkaloids. And, among the alkaloids present in Nicotiana, β-carboline (Harmane and Norharmane), Kynurenines are found to show anti-tumor effects, especially in the case of colon and breast cancer. Creating new or shunting of existing biosynthesis pathways in different species of Nicotiana resulted in de novo or increased synthesis of different anti-tumor molecules or their derivatives or precursors includ-ing Taxadiane (~22.5 µg/g), Artemisinin (~120 μg/g), Parthenolide (~2.05 ng/g), Costunolide (~60 ng/g), Etoposide (~1 mg/g), Crocin (~400 µg/g), Catharanthine (~60 ng/g), Tabersonine (~10 ng/g), Strictosidine (~0.23 mg/g), etc. Enrich precursor pool especially Dimethylallyl Diphos-phate (DMAPP) and down-regulating of other bi-product pathways, compartmentalization or metabolic shunting, or organelle-specific reconstitution of the precursor pool might trigger the enhanced accumulation of the targeted anticancer alkaloid in Nicotiana.
ARTICLE | doi:10.20944/preprints202303.0488.v1
Subject: Engineering, Other Keywords: aerodynamics; dynamic stall; engineering model; wind energy; wind turbine
Online: 28 March 2023 (12:43:07 CEST)
Considering the dynamic stall effects in engineering calculations is essential for correcting the aerodynamic loads acting on wind turbines, both during power production and stand-still cases, and impacts significantly the turbine aeroelastic stability. The employed dynamic stall model needs to be accurate and robust for a wide range of airfoils and range of angle of attack. The present studies are intended to demonstrate the performance of a recently implemented "IAG dynamic stall" model in a wind turbine design tool Bladed. The model is transformed from the indicial type of formulation into a state-space representation. The new model is validated against measurement data and other dynamic stall models in Bladed for various flow conditions and airfoils. It is demonstrated that the new model is able to reproduce the measured dynamic polar accurately without airfoil specific parameter calibration and has a superior performance compared to other models in Bladed.
ARTICLE | doi:10.20944/preprints202212.0157.v1
Subject: Engineering, Control And Systems Engineering Keywords: self-adaption; wireless sensors; model-based design; control engineering
Online: 8 December 2022 (10:24:09 CET)
The main objective of this work is the design and implementation of self-adaptive capabilities in wireless sensors by applying control engineering and model-based design methodologies. It has been addressed the problem related to the changes in the flow of data packets through the network connection and the excess energy consumption that this causes in these devices. To design the solution, a systemic characterization of the scheduling and execution process of embedded tasks on the device has been carried out. This means defining cause-effect relationships in the system and its modelling theoretically and/or experimentally. In turn, these models facilitate the design of control strategies to improve the dynamic behavior of the system. As a solution, a self-adaptation strategy based on feedforward control algorithm has been designed and developed, which has been applied to improve the dynamic behavior and resource consumption. The developed solution has been satisfactorily evaluated experimentally.
ARTICLE | doi:10.20944/preprints202211.0201.v1
Subject: Computer Science And Mathematics, Artificial Intelligence And Machine Learning Keywords: Natural Language Ontologies; Ontology Engineering; Ontology Development; Semantic Web
Online: 10 November 2022 (11:14:20 CET)
The goal of the next generation World Wide Web is machine readability through linked databases. To improve web search, integration, and mining in local languages like Urdu, there is a growing need to develop ontologies and vocabulary in these languages. The majority of people use the web in local languages for agriculture, social media interaction, news, etc. How to create agents for the integration of web data. In our country, the literacy ratio is very low and IT literacy is negligible. More comprehensive information for its target audience is only possible through the World Wide Web. Our first target is to improve and enhance the use of social media and the web in local languages. That will encourage its constructive use in Urdu for society and the economy. The Web in natural languages is the source of income for small and medium enterprises. The semantic web is concerned with linked databases and structured data. In this work, we are focused on some selected ontologies to be translated into natural languages. Expertise in Ontology Engineering helps us in job production. Ontology Engineering has extensive freelancing opportunities. Only if the web is correctly interpreted in regional languages is an economic boost achievable. A standardized foundation for data sharing and reuse on the internet is provided by the Semantic Web. In other words, a group of standards and technology that enables computers to comprehend the semantics (meaning) of material on the Web.
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: Chemistry And 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: Chemistry And 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
Subject: Environmental And Earth Sciences, Soil Science Keywords: Soil erosion; Defective sewer; soil science; soil engineering; soil
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: Biology And Life Sciences, Biology And Biotechnology 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: Chemistry And Materials Science, Metals, Alloys And 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: Chemistry And 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: Chemistry And 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: Biology And Life Sciences, Biochemistry And Molecular Biology 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: Chemistry And 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: Chemistry And 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 And Life Sciences, Anatomy And Physiology 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: Biology And Life Sciences, Biochemistry And Molecular Biology 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: Computer Science And Mathematics, Information Systems 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: Chemistry And Materials Science, Materials Science And Technology 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 And Photonics 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: Chemistry And 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: Chemistry And 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: Chemistry And 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.