Structure and Stability of SnO2 Nanocrystals and Surface-Bound Water Species

2013 ◽  
Vol 135 (18) ◽  
pp. 6885-6895 ◽  
Author(s):  
Hsiu-Wen Wang ◽  
David J. Wesolowski ◽  
Thomas E. Proffen ◽  
Lukas Vlcek ◽  
Wei Wang ◽  
...  
Keyword(s):  
Bound Water ◽  
Structure And Stability ◽  
Sno2 Nanocrystals ◽  
Water Species

Mathematical Models of Papermaking

2001 ◽  
Vol 6 (1) ◽  
pp. 9-19 ◽  
Author(s):  
A. Buikis ◽  
J. Cepitis ◽  
H. Kalis ◽  
A. Reinfelds ◽  
A. Ancitis ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Initial Value Problems ◽  
Moisture Transfer ◽  
Bound Water ◽  
Drying Process ◽  
Initial Value ◽  
First Order ◽  
Heat And Moisture ◽  
The Mathematical Model ◽  
The Web

The mathematical model of wood drying based on detailed transport phenomena considering both heat and moisture transfer have been offered in article. The adjustment of this model to the drying process of papermaking is carried out for the range of moisture content corresponding to the period of drying in which vapour movement and bound water diffusion in the web are possible. By averaging as the desired models are obtained sequence of the initial value problems for systems of two nonlinear first order ordinary differential equations. 

Polyplex: A Promising Gene Delivery System

2019 ◽  
Vol 12 (6) ◽  
pp. 4681-4686
Author(s):  
Rohan Aggarwal ◽  
Monika Targhotra ◽  
Bhumika Kumar ◽  
P.K Sahoo ◽  
Meenakshi K Chauhan
Keyword(s):  
Gene Transfer ◽  
Gene Delivery ◽  
Delivery System ◽  
Viral Vectors ◽  
Gene Delivery System ◽  
Cationic Polymers ◽  
Therapeutic Application ◽  
Promising Alternative ◽  
Structure And Stability ◽  
The Past

In the past few years gene delivery system has gained a huge attention owing to its proved efficacy in several diseases especially in those caused by genetic and/oroncological malfunctioning. The effective gene delivery mainly depends on the carrier molecules that can ensure the safe and specific delivery of the nucleic acidmolecules. Viral vectors have been used for a longer period as the gene transfer vehicle. However, these viral vectors have potential immunological disadvantages that made them less preferred. Recently, non-viral vectors such as polyplexes have emerged as a promising alternative for viral vectors. Polyplexes are formed by conjugating a polymer with DNA and in maximum cases the cationic polymers are preferred over others. The structure and stability of the polyplexes depends on various factors. The ability of the polymer to condense the DNA mainly dictates the efficiency of the polyplex mediated transfection. In this review we are going to provide a framework for the synthesis and design of the polyplexes along with the structure and stability of the complexes pertaining to mechanism of action, characterization and therapeutic application, including polyethyleneimine mediated cytotoxicity as well as newer strategies for the generation of better polyplexes.

scholarly journals Elucidating the Molecular Mechanisms for the Interaction of Water with Polyethylene Glycol-Based Hydrogels: Influence of Ionic Strength and Gel Network Structure

Polymers ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 845
Author(s):  
Xin Yang ◽  
Bronwin Dargaville ◽  
Dietmar Hutmacher
Keyword(s):  
Polyethylene Glycol ◽  
Ionic Strength ◽  
Molecular Mechanisms ◽  
Repeat Unit ◽  
Bound Water ◽  
Weight Fraction ◽  
Swelling Ratio ◽  
Polyethylene Glycol Diacrylate ◽  
Glycol Diacrylate ◽  
Hydrogel System

The interaction of water within synthetic and natural hydrogel systems is of fundamental importance in biomaterial science. A systematic study is presented on the swelling behavior and states of water for a polyethylene glycol-diacrylate (PEGDA)-based model neutral hydrogel system that goes beyond previous studies reported in the literature. Hydrogels with different network structures are crosslinked and swollen in different combinations of water and phosphate-buffered saline (PBS). Network variables, polyethylene glycol (PEG) molecular weight (MW), and weight fraction are positively correlated with swelling ratio, while “non-freezable bound water” content decreases with PEG MW. The presence of ions has the greatest influence on equilibrium water and “freezable” and “non-freezable” water, with all hydrogel formulations showing a decreased swelling ratio and increased bound water as ionic strength increases. Similarly, the number of “non-freezable bound water” molecules, calculated from DSC data, is greatest—up to six molecules per PEG repeat unit—for gels swollen in PBS. Fundamentally, the balance of osmotic pressure and non-covalent bonding is a major factor within the molecular structure of the hydrogel system. The proposed model explains the dynamic interaction of water within hydrogels in an osmotic environment. This study will point toward a better understanding of the molecular nature of the water interface in hydrogels.

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