scholarly journals 326 IMBIBITION IN SUGARS AND DEHYDRATION ALLOW STRAWBERRY PLANTLETS TO SURVIVE CRYOPRESERVATION

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 477c-477
Author(s):  
Manfredo J. Seufferheld ◽  
Cecil Stushnoff
Keyword(s):  
Differential Scanning Calorimetry ◽  
Glass Transition ◽  
Survival Rate ◽  
Cold Acclimation ◽  
Model System ◽  
Scanning Calorimetry ◽  
Alginate Capsules ◽  
Melting Event ◽  
High Concentrations ◽  
Leaf Disks

Strawberry plantlets, regenerated from leaf disks, were used as a model system to study the effect of high concentrations of sugars and dehydration on survival during cryopreservation. After cold acclimation, plantlets imbibed for 3 days (one day each) in 0.5, 0.7 and 1.2 M sucrose and (1.0M sucrose + 0.2M raffinose) and desiccated to 25 % moisture (fwb) in alginate capsules consistently survived cryopreservation. Differential scanning calorimetry revealed only a very small exotherm between -20C and -28C during freezing; a glass transition at -50C and a small melting event at -10C during warming. Conversely, samples with the lowest survival rate, had a large nucleation exotherm at -30C and a devitrification exotherm between -70 and -40C. We conclude that imbibition with sugars, coupled with desiccation treatments, may be used to manipulate freeze tender tissues of strawberry to permit successful cryopreservation.

Evaluation of glass transition in model cell lines using differential scanning calorimetry

Cytotherapy ◽  
2021 ◽  
Vol 23 (5) ◽  
pp. S173
Author(s):  
C. Jones ◽  
J. Heimfeld ◽  
B.J. Hawkins ◽  
R. Marcu
Keyword(s):  
Differential Scanning Calorimetry ◽  
Glass Transition ◽  
Cell Lines ◽  
Scanning Calorimetry ◽  
Model Cell

scholarly journals Thermal analysis: basic concept of differential scanning calorimetry and thermogravimetry for beginners

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Nurul Fatahah Asyqin Zainal ◽  
Jean Marc Saiter ◽  
Suhaila Idayu Abdul Halim ◽  
Romain Lucas ◽  
Chin Han Chan
Keyword(s):  
Thermal Analysis ◽  
Differential Scanning Calorimetry ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Commercial Application ◽  
Scanning Calorimetry ◽  
Teaching Activities ◽  
Sample Decomposition ◽  
Calibration Baseline

AbstractWe present an overview for the basic fundamental of thermal analysis, which is applicable for educational purposes, especially for lecturers at the universities, who may refer to the articles as the references to “teach” or to “lecture” to final year project students or young researchers who are working on their postgraduate projects. Description of basic instrumentation [i.e. differential scanning calorimetry (DSC) and thermogravimetry (TGA)] covers from what we should know about the instrument, calibration, baseline and samples’ signal. We also provide the step-by-step guides for the estimation of the glass transition temperature after DSC as well as examples and exercises are included, which are applicable for teaching activities. Glass transition temperature is an important property for commercial application of a polymeric material, e.g. packaging, automotive, etc. TGA is also highlighted where the analysis gives important thermal degradation information of a material to avoid sample decomposition during the DSC measurement. The step-by-step guides of the estimation of the activation energy after TGA based on Hoffman’s Arrhenius-like relationship are also provided.

scholarly journals Swelling properties of chitosan hydrogels

2004 ◽  
Vol 22 (1) ◽  
pp. 32 ◽  
Author(s):  
David R Rohindra ◽  
Ashveen V Nand ◽  
Jagjit R Khurma
Keyword(s):  
Differential Scanning Calorimetry ◽  
Fourier Transform ◽  
Glass Transition ◽  
Free Water ◽  
Scanning Calorimetry ◽  
Swelling Behaviour ◽  
Swelling Properties ◽  
Different Temperatures ◽  
Ft Ir ◽  
Chitosan Hydrogels

Chitosan hydrogels were prepared by crosslinking chitosan with glutaraldehyde. The swelling behaviour of the crosslinked and uncross-linked hydrogels was measured by swelling the gels in media of different pH and at different temperatures. The swelling behavior was observed to be dependent on pH, temperature and the degree of crosslinking. The gel films were characterized by Fourier transform Infrared spectroscopy (FT-IR) and Differential Scanning Calorimetry (DSC). The glass transition temperature (Tg) and the amount of free water in the hydrogels decreased with increasing crosslinking in the hydrogels.

scholarly journals Miscibility, melting and crystallization of poly(ε-caprolactone) and poly (vinyl formal) blend

2007 ◽  
Vol 25 (1) ◽  
pp. 53 ◽  
Author(s):  
David R. Rohindra ◽  
Jagjit R. Khurma
Keyword(s):  
Growth Rate ◽  
Differential Scanning Calorimetry ◽  
Fourier Transform ◽  
Glass Transition ◽  
Optical Microscopy ◽  
Crystallization Process ◽  
Scanning Calorimetry ◽  
Low Degree ◽  
Solution Cast ◽  
Melting And Crystallization

Solution cast blends of poly(e-caprolactone) [PCL] and poly(vinyl formal) [PVF] from dichloromethane was investigated for miscibility by Differential Scanning Calorimetry [DSC], Fourier Transform Infrared Spectroscopy [FTIR] and optical microscopy. Melting (Tm) and crystallization (Tc) temperatures were for the PCL fraction while the glass transition temperature (Tg) was for PVF fraction in the blends. Blends with 20 wt% and less PCL showed a depression in Tm and Tc. Depression in Tc indicated that during the non-isothermal crystallization process, the presence of PVF decreased the PCL segments migrating to the crystallite-melt interface thus reducing the nucleation rate, growth rate and the thickness of the lamella resulting in a depressed Tm. Crystallinity (Xc) decreased gradually with decreasing content of PCL in the blend and was due to the dilution of PCL by PVF. A depressed Tg was observed for 10 wt% PCL blend and remained the same for all other blend compositions. These observations suggested that this blend system has very low degree of miscibility. The degree of miscibility increased at low polyester concentration. FTIR spectra of the blends with low polyester concentrations showed changes in the C=O, O-H and C-O-C regions in the blended PVF and PCL spectra. Optical microscopy showed phase separation in the melt and in the PCL spherulites.

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