scholarly journals RHEOLOGICAL ASPECTS OF THE FLOW OF THERMOSENSITIVE CHITOSAN SYSTEMS DURING INJECTION APPLICATION

2020 ◽  
Vol XXV ◽  
pp. 201-209
Author(s):  
Anna Rył ◽  
Piotr Owczarz
Keyword(s):  
Phase Transition ◽  
Room Temperature ◽  
Sol Gel ◽  
Pharmaceutical Applications ◽  
Gel Phase ◽  
Injection Temperature ◽  
Chitosan Hydrogels ◽  
The Many ◽  
Interesting Solution

The aim of this paper was to conduct preliminary instrumental tests to determine the possibility of injection applications for thermosensitive chitosan systems, including injection needles and application conditions. Among the many biomedical and pharmaceutical applications of chitosan, the minimally invasive thermosensitive scaffolds that form in vivo are an interesting solution. Despite many studies on colloidal chitosan systems undergoing sol-gel phase transition, almost no studies have examined their injectability. It has been stated that the use of acetic acid as a solvent reduces the forces needed for injection. Moreover, the key impact of injection temperature was determined. Storing the medium at room temperature before the injectability test led to a decrease in the value of forces needed for injection. The obtained results are discussed based on the change of the rheological properties of the chitosan hydrogels.

scholarly journals Influence of fish collagen on viscoelastic properties and sol-gel phase transition of chitosan solutions

2018 ◽  
pp. 14-23
Author(s):  
Anna Ryl ◽  
Piotr Owczarz
Keyword(s):  
Mechanical Properties ◽  
Phase Transition ◽  
Monotone Function ◽  
Sol Gel ◽  
Measurement Techniques ◽  
Fish Collagen ◽  
Thermosensitive Hydrogels ◽  
Gel Phase ◽  
Chitosan Hydrogels ◽  
Increasing Temperature

The thermosensitive hydrogels are widely used in tissue engineering due to their non-invasive application. Special interest of researchers, due to the specific characteristics of both materials, is aimed at composites of natural origin obtained from chitosan hydrogels combined with collagen. The mechanical properties of the thermosensitive chitosan-fish collagen hydrogels and the sol-gel phase transition parameters were determined by the rotational rheometry measurement techniques. Based on comparison of the obtained storage modulus G' curves, it was found that the addition of collagen negatively affects the mechanical properties of composite scaffolds. The addition of this protein substance decreases their elasticity. Only the smallest concentration (0.25g collagen/1 g chitosan) of collagen improves the mechanical properties of composite hydrogels, from 56 kPa to 61 kPa. Conducted non-isothermal studies allowed to conclude that the addition of collagen causes an increasing temperature of sol-gel phase transition. However, the observed changes are not a monotone function of the biopolymer concentration.

Sol-gel phase transition of brucine-appended porphyrin gelator: a study by vibrational circular dichroism spectroscopy

2002 ◽  
Vol 13 (24) ◽  
pp. 2661-2666 ◽  
Author(s):  
Vladimı́r Setnička ◽  
Marie Urbanová ◽  
Statis Pataridis ◽  
Vladimı́r Král ◽  
Karel Volka
Keyword(s):  
Phase Transition ◽  
Circular Dichroism ◽  
Sol Gel ◽  
Circular Dichroism Spectroscopy ◽  
Vibrational Circular Dichroism ◽  
Gel Phase ◽  
Circular Dichroïsm

Investigations of PbxSr1-xTiO3 Thin Films and Ceramics for Microelectronic Applications

2004 ◽  
Vol 811 ◽  
Author(s):  
M. Jain ◽  
Yu.I. Yuzyuk ◽  
R.S. Katiyar ◽  
Y. Somiya ◽  
A.S. Bhalla ◽  
...  
Keyword(s):  
Thin Films ◽  
Phase Transition ◽  
Room Temperature ◽  
Sol Gel ◽  
Solid State Reaction Method ◽  
Phase Shifters ◽  
Conventional Solid State Reaction ◽  
Mode Behavior ◽  
Dielectric Devices ◽  
Pst System

ABSTRACTWe have investigated electrical and optical properties of the lead strontium titanate {(PbxSr1-x)TiO3 or PST} ceramic and dielectric properties of the thin films of PST at low and high frequencies. (PbxSr1-x)TiO3 compositions with × ≤ 0.4 are paraelectric at room temperature and exhibit ferroelectric phase transition below room temperature. Only one phase transition in the PST system (compared to three in BaxSr1-xTiO3) was recorded. The studies indicated that PST has potential for tunable microwave devices in the paraelectric phase. In the present studies, Pb0.3Sr0.7TiO3 (PST30) ceramic was prepared by the conventional solid-state reaction method and thin films of PST were prepared by sol-gel technique. Structural, microstructural, dielectric, and Raman measurements were performed on these samples. Sharp phase transition was observed in case of the ceramic by dielectric and Raman measurements at 283 K. Raman measurements revealed well-pronounced soft-mode behavior below the Curie temperature in PST ceramic. The thin film of PST deposited on lanthanum aluminate substrate was highly (100) oriented and showed dielectric maxima at ∼280 K, which was close to that in case of the bulk. Eight element coupled micro-strip phase shifters (CMPS) was fabricated on the PST film and tested in the frequency range of 15-17 GHz. The average figure of merit of 49 °/dB for PST30 film in the Ku band at 533 kV/cm suggests the potentiality of these films for high frequency tunable dielectric devices.

Quater-, Quinque-, and Sexithiophene Organogelators: Unique Thermochromism and Heating-Free Sol-Gel Phase Transition

2005 ◽  
Vol 11 (16) ◽  
pp. 4735-4742 ◽  
Author(s):  
Shin-ichiro Kawano ◽  
Norifumi Fujita ◽  
Seiji Shinkai
Keyword(s):  
Phase Transition ◽  
Sol Gel ◽  
Gel Phase

scholarly journals Thermal resilience of ensilicated lysozyme via calorimetric and in vivo analysis

RSC Advances ◽  
2020 ◽  
Vol 10 (50) ◽  
pp. 29789-29796
Author(s):  
A. Doekhie ◽  
M. N. Slade ◽  
L. Cliff ◽  
L. Weaver ◽  
R. Castaing ◽  
...  
Keyword(s):  
Room Temperature ◽  
Sol Gel ◽  
Silica Shell ◽  
Room Temperature Storage ◽  
Sol Gel Process ◽  
In Vivo Analysis ◽  
Novel Method ◽  
Temperature Storage

Ensilication is a novel method of protein thermal stabilisation using silica. It uses a modified sol–gel process which tailor fits a protective silica shell around the protein to enable room temperature storage of biopharmaceuticals.

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