scholarly journals Research Progress on Synthesis and Application of Cyclodextrin Polymers

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 1090
Author(s):  
Yuan Liu ◽  
Ting Lin ◽  
Cui Cheng ◽  
Qiaowen Wang ◽  
Shujin Lin ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Materials Science ◽  
Polymer Materials ◽  
Research Progress ◽  
Structure Characteristic ◽  
Separation Science ◽  
Cavity Structure ◽  
Cyclodextrin Polymers ◽  
The Stability ◽  
Analytical Separation

Cyclodextrins (CDs) are a series of cyclic oligosaccharides formed by amylose under the action of CD glucosyltransferase that is produced by Bacillus. After being modified by polymerization, substitution and grafting, high molecular weight cyclodextrin polymers (pCDs) containing multiple CD units can be obtained. pCDs retain the internal hydrophobic-external hydrophilic cavity structure characteristic of CDs, while also possessing the stability of polymer. They are a class of functional polymer materials with strong development potential and have been applied in many fields. This review introduces the research progress of pCDs, including the synthesis of pCDs and their applications in analytical separation science, materials science, and biomedicine.

scholarly journals Development and Characterization of Two Types of Surface Displayed Levansucrases for Levan Biosynthesis

Catalysts ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 757
Author(s):  
Huiyi Shang ◽  
Danni Yang ◽  
Dairong Qiao ◽  
Hui Xu ◽  
Yi Cao
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Molecular Weight ◽  
Large Scale ◽  
Surface Display ◽  
Yeast Surface Display ◽  
Fusion Partner ◽  
Whole Cell ◽  
Food Industries ◽  
Yeast Surface ◽  
The Stability

Levan has wide applications in chemical, cosmetic, pharmaceutical and food industries. The free levansucrase is usually used in the biosynthesis of levan, but the poor reusability and low stability of free levansucrase have limited its large-scale use. To address this problem, the surface-displayed levansucrase in Saccharomyces cerevisiae were generated and evaluated in this study. The levansucrase from Zymomonas mobilis was displayed on the cell surface of Saccharomyces cerevisiae EBY100 using a various yeast surface display platform. The N-terminal fusion partner is based on a-agglutinin, and the C-terminal one is Flo1p. The yield of levan produced by these two whole-cell biocatalysts reaches 26 g/L and 34 g/L in 24 h, respectively. Meanwhile, the stability of the surface-displayed levansucrases is significantly enhanced. After six reuses, these two biocatalysts retained over 50% and 60% of their initial activities, respectively. Furthermore, the molecular weight and polydispersity test of the products suggested that the whole-cell biocatalyst of levansucrase displayed by Flo1p has more potentials in the production of levan with low molecular weight which is critical in certain applications. In conclusion, our method not only enable the possibility to reuse the enzyme, but also improves the stability of the enzyme.

The Simulation of Ultra-High Molecular Weight Polyethylene Cryogenic Pipeline Stress-Strain State

2021 ◽  
Vol 1031 ◽  
pp. 132-140
Author(s):  
Ekaterina Karyakina ◽  
Ildar Shammazov ◽  
Vladimir Voronov ◽  
Aleksey Shalygin
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Strain State ◽  
Polymer Materials ◽  
Creep Process ◽  
Cryogenic Temperatures ◽  
Stress Strain ◽  
Stress Strain State ◽  
Cryogenic Pipeline ◽  
Ultra High Molecular Weight

At present the production of polymer materials is developing intensively, new materials, comparable with steels in their strength properties have recently appeared. In this connection, the analysis of polymer materials applied in the pipe industry has been carried out, and the use of ultra-high molecular weight polyethylene (UHMWPE) is proposed as a structural pipeline material, allowing pipes to operate at cryogenic temperatures. The focal point of the article is the consideration of the fracture mechanisms of those materials and the nature of the change in the mechanical properties of UHMWPE under cryogenic temperatures, also taking into account the creep process. The expression for determining the value of the creep modulus depending on the temperature and operating time was obtained. A method is proposed for conducting initial strength estimation. Moreover, the computer model of stress-strain state of an underground cryogenic polymer pipeline for liquefied natural gas transportation is obtained. The results of simulation depict the potential possibility of using of UHMWPE for the cryogenic pipeline construction

Research Progress of the Stability and Photodetectors Applications of Organic-inorganic Hybrid Halide Perovskite Materials （Invited）

2021 ◽  
Vol 50 (1) ◽  
pp. 26-44
Author(s):  
姚丽娟 Lijuan YAO ◽  
方铉 Xuan FANG ◽  
房丹 Dan FANG ◽  
高晨皓 Chenhao GAO ◽  
刘胜达 Shengda LIU ◽  
...  
Keyword(s):  
Research Progress ◽  
Inorganic Hybrid ◽  
Perovskite Materials ◽  
Halide Perovskite ◽  
The Stability

Magnetic nanoparticles (Fe3O4 NPs) fabricated composite microgels and their applications in different fields

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Khalida Naseem
Keyword(s):  
Research Progress ◽  
Composite Particles ◽  
External Magnet ◽  
Drug Delivery Vehicles ◽  
Microgel Particles ◽  
Delivery Vehicles ◽  
The Stability ◽  
Nano Formulation ◽  
Magnetic Nanoparticles Fe3o4 ◽  
Micro Reactor

Abstract This article encircles the research progress of Fe3O4 NPs loaded composite microgel particles. Preparation methodologies, properties and applications of Fe3O4 NPs loaded composite microgel particles are elaborated here. The effect of different factors on the stability and tunable properties of Fe3O4 NPs loaded composite microgel particles was also investigated in detail. These composite particles have exceptional magnetic properties that make them demanding composite nano-formulation in different fields. Applications of these composite microgel particles in different fields as micro-reactor, drug delivery vehicles, and in adsorption and catalysis have also been elaborated in detail. These composite microgel particles can easily be recovered from the reaction mixture by applying an external magnet due to the presence of fabricated Fe3O4 NPs.

Self-healable Functional Polymers based on Diels-Alder ‘Click Chemistry’ Involving Substituted Furan and Triazolinedione Derivatives; A Simple and Very Fast Approach

2021 ◽  
Author(s):  
Prantik Mondal ◽  
Gourhari Jana ◽  
Tuhin Subhra Pal ◽  
Pratim K. Chattaraj ◽  
Nikhil K Singha
Keyword(s):  
Click Chemistry ◽  
Materials Science ◽  
Functional Polymers ◽  
Diels Alder ◽  
Polymer Materials ◽  
Self Healing ◽  
Natural Phenomena ◽  
Science And Engineering ◽  
Fast Approach ◽  
Materials Science And Engineering

Nowadays, the design of functional polymer materials that can mimic natural phenomena, e.g., self-healing of skin cuts, has got a tremendous interest in materials science and engineering. Recently, 1,2,4-triazoline-3,5-dione (TAD)...

Fundamental and Technological Aspects of Actinide Oxide Pyrochlores: Relevance For Immobilization Matrices

1999 ◽  
Vol 556 ◽  
Author(s):  
P. E. Raison ◽  
R. G. Haire ◽  
T. Sato ◽  
T. Ogawa
Keyword(s):  
Elevated Temperatures ◽  
Materials Science ◽  
Oxidation Potential ◽  
Oxygen Stoichiometry ◽  
X Ray Diffraction ◽  
X Ray ◽  
Oxidation Reduction ◽  
Reduction Cycle ◽  
Fluorite Type ◽  
The Stability

AbstractPolycrystalline pyrochlore oxides consisting of selected f elements (lanthanides and actinides) and Zr and Hf have been prepared and characterized. Characterization to date has been primarily by X-ray diffraction, both at room and at elevated temperatures. Initial studies concentrated on selected lanthanides and the Np, Pu and Am analogs (reported here) but have been extended to the other actinide elements through Cf. Data from these studies have been used to establish a systematic correlation regarding the fundamental materials science of these particular pyrochlores and structurally related fluorite-type dioxides. In addition to pursuing their materials science, we have addressed some potential technological applications for these materials. Some of the latter concern: (1) immobilization matrices; (2) materials for transmutation concepts; and (3) special nuclear fuel forms that can minimize the generation of nuclear wastes. For f elements that display both a III and IV oxidation state in oxide matrices, the synthetic path required for producing the desired pyrochlore oxide is dictated by their pseudo-oxidation potential the stability of the compound towards oxygen uptake. For the f elements that display an oxidationreduction cycle for pyrochlore-dioxide solid solution, X-ray diffraction can be used to identify the composition in the oxidation-reduction cycle, the oxygen stoichiometry and/or the composition. This paper concentrates on the Np, Pu and Am systems, and addresses the above aspects, the role of the crystal matrix in controlling the ceramic products as well as discussingsome custom-tailored materials.

scholarly journals Matrix-graph model of the polymer materials destruction process

2018 ◽  
Vol 80 (3) ◽  
pp. 50-55
Author(s):  
A. A. Khvostov ◽  
S. G. Tikhomirov ◽  
I. A. Khaustov ◽  
A. A. Zhuravlev ◽  
A. V. Karmanov
Keyword(s):  
Mathematical Model ◽  
Molecular Weight ◽  
Molecular Weight Distribution ◽  
Weight Distribution ◽  
Graph Model ◽  
Polymer Materials ◽  
Simulation Environment ◽  
Destruction Process ◽  
Molecular Weights ◽  
The Mathematical Model

The paper deals with the problem of mathematical modeling of the process of thermochemical destruction using the theory of graphs. To synthesize a mathematical model, the Markov chain is used. For the formalization of the model a matrix-graph method of coding is used. It is proposed to consider the process of destruction as a random process, under which the state of the system changes, characterized by the proportion of macromolecules in each fraction of the molecular mass distribution. The intensities of transitions from state to state characterize the corresponding rates of destruction processes for each fraction of the molecular weight distribution (MWD). The processes of crosslinking and polymerization in this work have been neglected, and it is accepted that there is a probability of transition from any state with a lower order index (corresponding to fractions with higher molecular weights) to any state with a higher index (corresponding fractions with lower molecular weights). A computational formula is presented for estimating the number of arcs and model parameters from a given number of fractions of the molecular weight distribution of the polymer. An example of coding in a matrix form of a graph model of the process of degradation of polybutadiene in solution for the case of six fractions of the molecular weight distribution is shown. As the simulation environment, the interactive graphical simulation environment of MathWorks Simulink is used. To evaluate the parameters of the mathematical model, experimental studies of the degradation of polybutadiene in solution were carried out. The chromatography of the polybutadiene solution was used as the initial data for the estimation of the MWD polymer. The considered matrix-graph representation of the structure of the mathematical model of the polymer destruction process makes it possible to simplify the compilation of the model and its software implementation in the case of a large number of vertices of the graph describing the process of destruction

scholarly journals The multiple complexes formed by the interaction of platelet factor 4 with heparin

1980 ◽  
Vol 191 (3) ◽  
pp. 769-776 ◽  
Author(s):  
P E Bock ◽  
M Luscombe ◽  
S E Marshall ◽  
D S Pepper ◽  
J J Holbrook
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Chain Length ◽  
Salt Concentration ◽  
Human Platelet ◽  
Platelet Factor 4 ◽  
High Protein ◽  
Platelet Factor ◽  
The Stability ◽  
Very High

The anisotropy of the fluorescence of dansyl (5-dimethylaminonaphthalene-1- sulphonyl) groups covalently attached to human platelet factor 4 was used to detect the macromolecular compounds formed when the factor was mixed with heparin. At low heparin/protein ratios a very-high-molecular-weight compound (1) was formed that dissociated to give a smaller compound (2) when excess heparin was added. 2. A large complex was also detected as a precipitate that formed at high protein concentrations in chloride buffer. It contained 15.7% (w/w) polysaccharide, equivalent to four or five heparin tetrasaccharide units per protein tetramer. In this complex, more than one molecule of protein binds to each heparin molecule of molecular weight greater than about 6 × 10(3).3. The stability of these complexes varied with pH, salt concentration and the chain length of the heparin. The limit complexes found in excess of the larger heparins consisted of only one heparin molecule per protein tetramer, and the failure to observe complexes with four heparin molecules/protein tetramer is discussed.

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