Investigations On Glassy State of Sugarcane Shoot Tips By Dsc Standardization of Pvs2

<a></a><a>Quantitative comparison of atomistic simulations with experiment for glass-forming materials is made difficult by the vast mismatch between computationally and experimentally accessible timescales. Recently, we presented results for an epoxy network showing that the computation of specific volume vs. temperature as a function of cooling rate in conjunction with the time–temperature superposition principle (TTSP) enables direct quantitative comparison of simulation with experiment. Here, we follow-up and present results for the translational dynamics of the same material over a temperature range from the rubbery to the glassy state. Using TTSP, we obtain results for translational dynamics out to 10<sup>9</sup> s in TTSP reduced time – a macroscopic timescale. Further, we show that the mean squared displacement (MSD) trends of the network atoms can be collapsed onto a master curve at a reference temperature. The computational master curve is compared with the experimental master curve of the creep compliance for the same network using literature data. We find that the temporal features of the two data sets can be quantitatively compared providing an integrated view relating molecular level dynamics to the macroscopic thermophysical measurement. The time-shift factors needed for the superposition also show excellent agreement with experiment further establishing the veracity of the approach</a>.

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Encapsulation-dehydration based cryopreservation of Rauwolfia shoot tips and their regeneration potential in vitro

Journal of Crop and Weed ◽

10.22271/09746315.2020.v16.i1.1276 ◽

2020 ◽

Vol 16 (1) ◽

pp. 82-87

Author(s):

P. KISKU ◽

S. SAHU ◽

U. SALMA ◽

S. SINHA RAY ◽

P. SAHA ◽

...

Keyword(s):

Shoot Tips ◽

Regeneration Potential

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RAPID PROPAGATION FROM IN VITRO CULTURED SEEDLING SHOOT-TIPS OF CULINARY RHUBARB (RHEUM RHAPONTICUM L.)

Acta Horticulturae ◽

10.17660/actahortic.2011.923.12 ◽

2011 ◽

pp. 91-96

Author(s):

Y. Zhao ◽

Z. Cai ◽

Y. Zhou ◽

S. Chen

Keyword(s):

Shoot Tips ◽

Rapid Propagation ◽

Rheum Rhaponticum

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Gold nanoparticles affect the cryopreservation efficiency of in vitro-derived shoot tips of bleeding heart

Plant Cell Tissue and Organ Culture (PCTOC) ◽

10.1007/s11240-021-02069-4 ◽

2021 ◽

Author(s):

Dariusz Kulus ◽

Alicja Tymoszuk

Keyword(s):

Gold Nanoparticles ◽

Alginate Bead ◽

Stability Index ◽

Shoot Tips ◽

Start Codon ◽

Lamprocapnos Spectabilis ◽

Colloid Dispersion ◽

Recovery Medium ◽

Alginate Matrix

AbstractThe popularity of nanoparticles (NPs) is continuously increasing. To date, however, there has been little research on the application of NPs in plant cryopreservation, i.e. storage of tissues in liquid nitrogen (LN). The aim of this study is to analyze the effect and evaluate the usefulness of gold nanoparticles (AuNPs) in regard to cryobiology studies. In vitro-derived shoot tips of Lamprocapnos spectabilis ‘Valentine’ were cryopreserved with the encapsulation-vitrification protocol. Gold nanoparticles (at 10–30 ppm concentration; 13 nm in size) were added either into the preculture medium; to the protective bead matrix during encapsulation; or to the recovery medium after rewarming of samples. The control plants were produced from cryopreserved explants non-treated with nanoparticles or treated with colloid dispersion medium without NPs. A non-LN-treated standard was also considered. The influence of AuNPs on the cryopreservation efficiency was determined by evaluating the recovery rate of explants and their morphogenic response; the membrane stability index (MSI); the concentration of pigments in shoots; and the antioxidant enzymes activity. The genetic stability of the plant material was evaluated using Start Codon Targeted Polymorphism (SCoT) markers. It was found that 10 ppm of AuNPs added into the alginate bead matrix improved the recovery level of LN-derived shoot tips (70.0%) compared to the non-NPs-treated cryopreserved control (50.5%). On the other hand, the presence of nanoparticles in the recovery medium had a deleterious effect on the survival of explants. AuNPs usually had no impact on the MSI (73.9–85.9%), except for those added into the recovery medium at the concentration of 30 ppm (decline to 55.8%). All LN-derived shoots were shorter and contained less chlorophyll and carotenoids than the untreated standard. Moreover, the application of AuNPs affected the enzymatic activity in L. spectabilis. Minor genetic variation was found in 8.6% of plants if AuNPs were added either into the preculture medium (at 10 and 20 ppm) or to the alginate matrix (at 30 ppm). In conclusion, AuNPs added at a lower concentration (10 ppm) into the protective bead matrix can significantly improve the cryopreservation efficiency in L. spectabilis with no alternation in the DNA sequence.

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Physical Aging Behavior of a Glassy Polyether

Polymers ◽

10.3390/polym13060954 ◽

2021 ◽

Vol 13 (6) ◽

pp. 954

Author(s):

Xavier Monnier ◽

Sara Marina ◽

Xabier Lopez de Pariza ◽

Haritz Sardón ◽

Jaime Martin ◽

...

Keyword(s):

Glass Transition ◽

Transition Temperature ◽

Glass Transition Temperature ◽

Physical Aging ◽

Glassy State ◽

Aging Behavior ◽

Scanning Calorimetry ◽

Narrow Temperature Range ◽

Glass Forming ◽

Fast Scanning Calorimetry

The present work aims to provide insights on recent findings indicating the presence of multiple equilibration mechanisms in physical aging of glasses. To this aim, we have investigated a glass forming polyether, poly(1-4 cyclohexane di-methanol) (PCDM), by following the evolution of the enthalpic state during physical aging by fast scanning calorimetry (FSC). The main results of our study indicate that physical aging persists at temperatures way below the glass transition temperature and, in a narrow temperature range, is characterized by a two steps evolution of the enthalpic state. Altogether, our results indicate that the simple old-standing view of physical aging as triggered by the α relaxation does not hold true when aging is carried out deep in the glassy state.

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Analysis of PLA Composite Filaments Reinforced with Lignin and Polymerised-Lignin-Treated NFC

Polymers ◽

10.3390/polym13132174 ◽

2021 ◽

Vol 13 (13) ◽

pp. 2174

Author(s):

Diana Gregor-Svetec ◽

Mirjam Leskovšek ◽

Blaž Leskovar ◽

Urška Stanković Elesini ◽

Urška Vrabič-Brodnjak

Keyword(s):

Electron Microscopy ◽

Mechanical Properties ◽

Scanning Electron Microscopy ◽

Tensile Strength ◽

Glassy State ◽

Nanofibrillated Cellulose ◽

Dynamic Mechanical Properties ◽

Initial Modulus ◽

Surface Modified ◽

Scanning Electron

Polylactic acid (PLA) is one of the most suitable materials for 3D printing. Blending with nanoparticles improves some of its properties, broadening its application possibilities. The article presents a study of composite PLA matrix filaments with added unmodified and lignin/polymerised lignin surface-modified nanofibrillated cellulose (NFC). The influence of untreated and surface-modified NFC on morphological, mechanical, technological, infrared spectroscopic, and dynamic mechanical properties was evaluated for different groups of samples. As determined by the stereo and scanning electron microscopy, the unmodified and surface-modified NFCs with lignin and polymerised lignin were present in the form of plate-shaped agglomerates. The addition of NFC slightly reduced the filaments’ tensile strength, stretchability, and ability to absorb energy, while in contrast, the initial modulus slightly improved. By adding NFC to the PLA matrix, the bending storage modulus (E’) decreased slightly at lower temperatures, especially in the PLA samples with 3 wt% and 5 wt% NFC. When NFC was modified with lignin and polymerised lignin, an increase in E’ was noticed, especially in the glassy state.

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Combined thermal analysis of plant oils

Journal of Thermal Analysis and Calorimetry ◽

10.1007/s10973-020-10470-y ◽

2021 ◽

Author(s):

Kinga Tamási ◽

Kálmán Marossy

Keyword(s):

Thermal Analysis ◽

Differential Scanning Calorimetry ◽

Low Temperature ◽

Glassy State ◽

Mechanical Analysis ◽

Plant Oils ◽

Scanning Calorimetry ◽

Natural Plant ◽

The Moment ◽

Current Reversal

AbstractThe paper deals with the study of seven selected natural plant oils. Differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA) and thermally stimulated discharge (TSD) methods were used. It has been found that most of the oils tested are in a glassy state at low temperature and have multiple transitions in the low temperature range. DSC shows complex melting-like processes or glass transition. For both DMA and TSD, the scaffold supportive method was used and found as a suitable one. DMA and TSD proved more sensitive than DSC and revealed at least two transitions between − 120 and − 40 °C. In the case of three oils (argan, avocado and sunflower), current reversal was observed by TSD; this symptom cannot be fully explained at the moment.

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