scholarly journals Recent advances in the microbial synthesis of lactate-based copolymer

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Pengye Guo ◽  
Yuanchan Luo ◽  
Ju Wu ◽  
Hui Wu
Keyword(s):  
Metabolic Engineering ◽  
Renewable Resources ◽  
Enzyme Engineering ◽  
Synthesis Process ◽  
Advantages And Disadvantages ◽  
Wide Range ◽  
Monomer Fraction ◽  
Degradable Plastics ◽  
The Difference ◽  
Application Fields

AbstractDue to the increasing environmental pollution of un-degradable plastics and the consumption of non-renewable resources, more attention has been attracted by new bio-degradable/based polymers produced from renewable resources. Polylactic acid (PLA) is one of the most representative bio-based materials, with obvious advantages and disadvantages, and has a wide range of applications in industry, medicine, and research. By copolymerizing to make up for its deficiencies, the obtained copolymers have more excellent properties. The development of a one-step microbial metabolism production process of the lactate (LA)-based copolymers overcomes the inherent shortcomings in the traditional chemical synthesis process. The most common lactate-based copolymer is poly(lactate-co-3-hydroxybutyrate) [P(LA-co-3HB)], within which the difference of LA monomer fraction will cause the change in the material properties. It is necessary to regulate LA monomer fraction by appropriate methods. Based on synthetic biology and systems metabolic engineering, this review mainly focus on how did the different production strategies (such as enzyme engineering, fermentation engineering, etc.) of P(LA-co-3HB) optimize the chassis cells to efficiently produce it. In addition, the metabolic engineering strategies of some other lactate-based copolymers are also introduced in this article. These studies would facilitate to expand the application fields of the corresponding materials.

Overview of Enzyme Engineering Towards the Production of Hyaluronic Acid with Tailored Molecular Weight

2021 ◽  
Vol 23 ◽  
Author(s):  
Tahereh Ebrahimi ◽  
Kamran Hosseini ◽  
Hossein Ahangari ◽  
Pourya Gholizadeh ◽  
Vahideh Tarhriz
Keyword(s):  
Molecular Weight ◽  
Hyaluronic Acid ◽  
Critical Role ◽  
Biological Properties ◽  
Research Field ◽  
Enzyme Engineering ◽  
The Body ◽  
Synthesis Process ◽  
Hyaluronan Synthase ◽  
Wide Range

: Hyaluronic acid or hyaluronan (HA) is a natural biopolymer composed of D-glucuronic acid and N-acetylglucosamine units, distributed as a non-sulfated and anionic glycosaminoglycan in important tissues of the body, and is commercially and biologically important. Its biological properties are determined by the molecular weight and dispersity which are suitable for particular medical and cosmetic applications. The synthesis of well-defined and monodisperse HA is still a significant obstacle and an impressive research field for advanced medical applications. High polydispersity by bacterial fermentation, the lack of knowledge of the mechanism required to start and continue the synthesis process, increased cost of raw materials to produce HA, clarification and explanation of factors limiting synthesis in bacterial systems are among the important challenges of hyaluronic acid synthesis. Hyaluronan synthase plays a critical role in HA molecular mass by producing a wide range of HA involved in various biological processes. Hyaluronan biosynthesis has been considered extensively; however, the control of its size and weight during the synthesis process is poorly investigated. This review focuses on these uncharted biochemical details to obtain the uniform chain lengths of Hyaluronan by protein engineering and regulating the function of Hyaluronan synthase.

scholarly journals A State of the Art Review of the Particle Finite Element Method (PFEM)

2020 ◽  
Vol 27 (5) ◽  
pp. 1709-1735
Author(s):  
Massimiliano Cremonesi ◽  
Alessandro Franci ◽  
Sergio Idelsohn ◽  
Eugenio Oñate
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Particle Finite Element Method ◽  
Advantages And Disadvantages ◽  
Lagrangian Framework ◽  
Starting Point ◽  
Wide Range ◽  
Basic Ideas ◽  
Application Fields ◽  
Element Method

Abstract The particle finite element method (PFEM) is a powerful and robust numerical tool for the simulation of multi-physics problems in evolving domains. The PFEM exploits the Lagrangian framework to automatically identify and follow interfaces between different materials (e.g. fluid–fluid, fluid–solid or free surfaces). The method solves the governing equations with the standard finite element method and overcomes mesh distortion issues using a fast and efficient remeshing procedure. The flexibility and robustness of the method together with its capability for dealing with large topological variations of the computational domains, explain its success for solving a wide range of industrial and engineering problems. This paper provides an extended overview of the theory and applications of the method, giving the tools required to understand the PFEM from its basic ideas to the more advanced applications. Moreover, this work aims to confirm the flexibility and robustness of the PFEM for a broad range of engineering applications. Furthermore, presenting the advantages and disadvantages of the method, this overview can be the starting point for improvements of PFEM technology and for widening its application fields.

scholarly journals Application of Geophysical Technique in the Coal Mining

2015 ◽  
Vol 11 (7) ◽  
pp. 11
Author(s):  
Lei Yue
Keyword(s):  
Coal Mining ◽  
Survey Methods ◽  
Geophysical Methods ◽  
Railway Tunnel ◽  
Advantages And Disadvantages ◽  
Geophysical Technique ◽  
The Difference ◽  
City Construction ◽  
Application Fields ◽  
Physical Principles

Although coal is one of the most prevalent energy resources in the world, coal production has been a high risk industry due to its frequent accidents, especially in the developing nations. As well known, the main reason for that problem is that the potential disaster sources are not prospected before coal mining. Hence, it is very necessary to be advanced prospecting before the coal mining. Usually, the work of advanced prospecting can be done by the geophysical methods. According to the difference of disasters source physical characters, different geophysical methods can be employed. Because of different geophysical methods owning their advantages and disadvantages, this paper provides a general introduction to the most important methods used in the coal mining. These methods represent a primary tool for advanced prospecting to the disaster source. Although their main application is in prospecting disaster source in the coal mining, the methods are also used in other fields, for example, railway tunnel, environmental engineering and city construction. Consequently, geophysical method is of importance not only to geophysicists but also to geologists, engineers and archaeologists. The paper only covers the basic physical principles, methodology, and application fields of the various survey methods

Comparative Effects of High-Tech Visual Scene Displays and Low-Tech Isolated Picture Symbols on Engagement From Students With Multiple Disabilities

2019 ◽  
Vol 50 (4) ◽  
pp. 693-702 ◽  
Author(s):  
Christine Holyfield ◽  
Sydney Brooks ◽  
Allison Schluterman
Keyword(s):  
Language Learning ◽  
Augmentative And Alternative Communication ◽  
Visual Analysis ◽  
Multiple Disabilities ◽  
Visual Scene ◽  
Future Research ◽  
High Tech ◽  
Single Subject ◽  
Wide Range ◽  
The Difference

Purpose Augmentative and alternative communication (AAC) is an intervention approach that can promote communication and language in children with multiple disabilities who are beginning communicators. While a wide range of AAC technologies are available, little is known about the comparative effects of specific technology options. Given that engagement can be low for beginning communicators with multiple disabilities, the current study provides initial information about the comparative effects of 2 AAC technology options—high-tech visual scene displays (VSDs) and low-tech isolated picture symbols—on engagement. Method Three elementary-age beginning communicators with multiple disabilities participated. The study used a single-subject, alternating treatment design with each technology serving as a condition. Participants interacted with their school speech-language pathologists using each of the 2 technologies across 5 sessions in a block randomized order. Results According to visual analysis and nonoverlap of all pairs calculations, all 3 participants demonstrated more engagement with the high-tech VSDs than the low-tech isolated picture symbols as measured by their seconds of gaze toward each technology option. Despite the difference in engagement observed, there was no clear difference across the 2 conditions in engagement toward the communication partner or use of the AAC. Conclusions Clinicians can consider measuring engagement when evaluating AAC technology options for children with multiple disabilities and should consider evaluating high-tech VSDs as 1 technology option for them. Future research must explore the extent to which differences in engagement to particular AAC technologies result in differences in communication and language learning over time as might be expected.

COMBINATORIAL POLYNOMIALLY COMPUTABLE CHARACTERISTICS OF SUBSTITUTIONS AND THEIR PROPERTIES

2020 ◽  
Vol 7 (2) ◽  
pp. 34-41
Author(s):  
VLADIMIR NIKONOV ◽  
◽  
ANTON ZOBOV ◽  
Keyword(s):  
Mathematical Expectation ◽  
Point Of View ◽  
Small Range ◽  
Computational Point ◽  
Wide Range ◽  
Bijective Function ◽  
The Difference ◽  
Element Base ◽  
Selection Of

The construction and selection of a suitable bijective function, that is, substitution, is now becoming an important applied task, particularly for building block encryption systems. Many articles have suggested using different approaches to determining the quality of substitution, but most of them are highly computationally complex. The solution of this problem will significantly expand the range of methods for constructing and analyzing scheme in information protection systems. The purpose of research is to find easily measurable characteristics of substitutions, allowing to evaluate their quality, and also measures of the proximity of a particular substitutions to a random one, or its distance from it. For this purpose, several characteristics were proposed in this work: difference and polynomial, and their mathematical expectation was found, as well as variance for the difference characteristic. This allows us to make a conclusion about its quality by comparing the result of calculating the characteristic for a particular substitution with the calculated mathematical expectation. From a computational point of view, the thesises of the article are of exceptional interest due to the simplicity of the algorithm for quantifying the quality of bijective function substitutions. By its nature, the operation of calculating the difference characteristic carries out a simple summation of integer terms in a fixed and small range. Such an operation, both in the modern and in the prospective element base, is embedded in the logic of a wide range of functional elements, especially when implementing computational actions in the optical range, or on other carriers related to the field of nanotechnology.

Microencapsulation and Nanoencapsulation: A Review

2017 ◽  
Vol 9 (3) ◽  
Author(s):  
V. Suganya ◽  
V. Anuradha
Keyword(s):  
Drug Release ◽  
New Technology ◽  
Inert Material ◽  
Food Industries ◽  
Control Drug ◽  
Advantages And Disadvantages ◽  
Nano Scale ◽  
Pharmaceutical Industries ◽  
The Difference ◽  
Control Drug Release

Encapsulation is a process of enclosing the substances within an inert material which protects from environment as well as control drug release. Recently, two type of encapsulation has been performed in several research. Nanoencapsulation is the coating of various substances within another material at sizes on the nano scale. Microencapsulation is similar to nanoencapsulation aside from it involving larger particles and having been done for a greater period of time than nanoencapsulation. Encapsulation is a new technology that has wide applications in pharmaceutical industries, agrochemical, food industries and cosmetics. In this review, the difference between micro and nano encapsulation has been explained. This article gives an overview of different methods and reason for encapsulation. The advantages and disadvantages of micro and nano encapsulation technology were also clearly mentioned in this paper.

Generalized Heterodyne Configurations for Photo-induced Force Microscopy

2019 ◽  
Author(s):  
Le Wang ◽  
Devon Jakob ◽  
Haomin Wang ◽  
Alexis Apostolos ◽  
Marcos M. Pires ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
Repetition Rate ◽  
Modulation Frequency ◽  
High Harmonic ◽  
Chemical Imaging ◽  
Heterodyne Detection ◽  
Force Microscopy ◽  
Wide Range ◽  
The Difference ◽  
Afm Cantilever

<div>Infrared chemical microscopy through mechanical probing of light-matter interactions by atomic force microscopy (AFM) bypasses the diffraction limit. One increasingly popular technique is photo-induced force microscopy (PiFM), which utilizes the mechanical heterodyne signal detection between cantilever mechanical resonant oscillations and the photo induced force from light-matter interaction. So far, photo induced force microscopy has been operated in only one heterodyne configuration. In this article, we generalize heterodyne configurations of photoinduced force microscopy by introducing two new schemes: harmonic heterodyne detection and sequential heterodyne detection. In harmonic heterodyne detection, the laser repetition rate matches integer fractions of the difference between the two mechanical resonant modes of the AFM cantilever. The high harmonic of the beating from the photothermal expansion mixes with the AFM cantilever oscillation to provide PiFM signal. In sequential heterodyne detection, the combination of the repetition rate of laser pulses and polarization modulation frequency matches the difference between two AFM mechanical modes, leading to detectable PiFM signals. These two generalized heterodyne configurations for photo induced force microscopy deliver new avenues for chemical imaging and broadband spectroscopy at ~10 nm spatial resolution. They are suitable for a wide range of heterogeneous materials across various disciplines: from structured polymer film, polaritonic boron nitride materials, to isolated bacterial peptidoglycan cell walls. The generalized heterodyne configurations introduce flexibility for the implementation of PiFM and related tapping mode AFM-IR, and provide possibilities for additional modulation channel in PiFM for targeted signal extraction with nanoscale spatial resolution.</div>

The Management of Post-Tonsillectomy Morbidity in Patients With Sleep Apnoea

2019 ◽  
Vol 70 (10) ◽  
pp. 3738-3740
Keyword(s):  
Day Surgery ◽  
Sleep Apnoea ◽  
Integrative Approach ◽  
Multicenter Studies ◽  
Therapeutic Modalities ◽  
Advantages And Disadvantages ◽  
Obstructive Sleep ◽  
Wide Range ◽  
The Impact ◽  
Surgery Center

The Tonsillectomy in children or adults is an intervention commonly encountered in the ENT (Ear Nose and Throat) and Head and Neck surgeon practice. The current tendency is to perform this type of surgery in major ambulatory surgery centers. Two objectives are thus pursued: first of all, the increase of the patient quality of life through the reintegration into the family as quickly as possible and secondly, the expenses associated with continuous hospitalization are reduced. Any tertiary (multidisciplinary) sleep center must ensure the complete diagnosis and treatment (including surgery) of sleep respiratory disorders. Under these conditions the selection of patients and especially the implementation of the specific protocols in order to control the postoperative complications it becomes essential. The present paper describes our experience of tonsillectomy as treatment for selected patients with chronic rhonchopathy (snoring) and mild to moderate obstructive sleep apnoea. It was presented the impact of antibiotics protocols in reducing the main morbid outcomes following tonsillectomy, in our day surgery center. The obtained results can also be a prerequisite for the integrative approach of the patients with sleep apnoea who were recommended surgical treatment. Considering the wide range of therapeutic modalities used in sleep apnoea, each with its specific advantages and disadvantages, more extensive and multicenter studies are needed. Keywords: post-tonsillectomy morbidity, day surgery center, sleep disorders

scholarly journals Advancements in Assessments of Bio-Tissue Engineering and Viable Cell Delivery Matrices Using Bile Acid-Based Pharmacological Biotechnologies

Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1861
Author(s):  
Armin Mooranian ◽  
Melissa Jones ◽  
Corina Mihaela Ionescu ◽  
Daniel Walker ◽  
Susbin Raj Wagle ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Viable Cell ◽  
Cell Delivery ◽  
Artificial Organ ◽  
Bioartificial Pancreas ◽  
Advantages And Disadvantages ◽  
Wide Range ◽  
Bioartificial Organs ◽  
Significant Interest ◽  
Modern Technologies

The utilisation of bioartificial organs is of significant interest to many due to their versatility in treating a wide range of disorders. Microencapsulation has a potentially significant role in such organs. In order to utilise microcapsules, accurate characterisation and analysis is required to assess their properties and suitability. Bioartificial organs or transplantable microdevices must also account for immunogenic considerations, which will be discussed in detail. One of the most characterized cases is the investigation into a bioartificial pancreas, including using microencapsulation of islets or other cells, and will be the focus subject of this review. Overall, this review will discuss the traditional and modern technologies which are necessary for the characterisation of properties for transplantable microdevices or organs, summarizing analysis of the microcapsule itself, cells and finally a working organ. Furthermore, immunogenic considerations of such organs are another important aspect which is addressed within this review. The various techniques, methodologies, advantages, and disadvantages will all be discussed. Hence, the purpose of this review is providing an updated examination of all processes for the analysis of a working, biocompatible artificial organ.

scholarly journals Metabolic engineering in woody plants: challenges, advances, and opportunities

aBIOTECH ◽  
2021 ◽  
Author(s):  
Shu Yu ◽  
Cody S. Bekkering ◽  
Li Tian
Keyword(s):  
Renewable Energy ◽  
Metabolic Engineering ◽  
Ecosystem Services ◽  
Plant Transformation ◽  
Woody Plants ◽  
Woody Plant ◽  
High Biomass ◽  
Generation Times ◽  
Wide Range ◽  
Biochemical Diversity

AbstractWoody plant species represent an invaluable reserve of biochemical diversity to which metabolic engineering can be applied to satisfy the need for commodity and specialty chemicals, pharmaceuticals, and renewable energy. Woody plants are particularly promising for this application due to their low input needs, high biomass, and immeasurable ecosystem services. However, existing challenges have hindered their widespread adoption in metabolic engineering efforts, such as long generation times, large and highly heterozygous genomes, and difficulties in transformation and regeneration. Recent advances in omics approaches, systems biology modeling, and plant transformation and regeneration methods provide effective approaches in overcoming these outstanding challenges. Promises brought by developments in this space are steadily opening the door to widespread metabolic engineering of woody plants to meet the global need for a wide range of sustainably sourced chemicals and materials.

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