scholarly journals Tunable Properties of Nature-Inspired N,N′-Alkylated Riboflavin Semiconductors

Molecules ◽  
2020 ◽  
Vol 26 (1) ◽  
pp. 27
Author(s):  
Jan Richtar ◽  
Lucia Ivanova ◽  
Dong Ryeol Whang ◽  
Cigdem Yumusak ◽  
Dominik Wielend ◽  
...  
Keyword(s):  
Thermal Stability ◽  
High Stability ◽  
Frontier Molecular Orbital ◽  
Synthetic Approach ◽  
Melting Points ◽  
Alkyl Groups ◽  
Application Potential ◽  
Comprehensive Characterization ◽  
Over Time

A series of novel soluble nature-inspired flavin derivatives substituted with short butyl and bulky ethyl-adamantyl alkyl groups was prepared via simple and straightforward synthetic approach with moderate to good yields. The comprehensive characterization of the materials, to assess their application potential, has demonstrated that the modification of the conjugated flavin core enables delicate tuning of the absorption and emission properties, optical bandgap, frontier molecular orbital energies, melting points, and thermal stability. Moreover, the thin films prepared thereof exhibit smooth and homogeneous morphology with generally high stability over time.

scholarly journals Novel Riboflavin-Inspired Conjugated Bio-Organic Semiconductors

Molecules ◽  
2018 ◽  
Vol 23 (9) ◽  
pp. 2271 ◽  
Author(s):  
Jan Richtar ◽  
Patricie Heinrichova ◽  
Dogukan Apaydin ◽  
Veronika Schmiedova ◽  
Cigdem Yumusak ◽  
...  
Keyword(s):  
Proton Transfer ◽  
Organic Semiconductors ◽  
Intramolecular Proton Transfer ◽  
Fine Tuning ◽  
Conjugated Materials ◽  
Absorption And Emission ◽  
Application Potential ◽  
Synthetic Approaches ◽  
Comprehensive Characterization

Flavins are known to be extremely versatile, thus enabling routes to innumerable modifications in order to obtain desired properties. Thus, in the present paper, the group of bio-inspired conjugated materials based on the alloxazine core is synthetized using two efficient novel synthetic approaches providing relatively high reaction yields. The comprehensive characterization of the materials, in order to evaluate the properties and application potential, has shown that the modification of the initial alloxazine core with aromatic substituents allows fine tuning of the optical bandgap, position of electronic orbitals, absorption and emission properties. Interestingly, the compounds possess multichromophoric behavior, which is assumed to be the results of an intramolecular proton transfer.

scholarly journals Synthesis and characterization of kraft lignin-based epoxy resins

BioResources ◽  
2011 ◽  
Vol 6 (3) ◽  
pp. 2492-2503
Author(s):  
Nour-Eddine El Mansouri ◽  
Qiaolong Yuan ◽  
Farong Huang
Keyword(s):  
Thermal Stability ◽  
Epoxy Resins ◽  
1H Nmr Spectroscopy ◽  
Kraft Lignin ◽  
Synthesis And Characterization ◽  
Index Test ◽  
Optimal Conditions ◽  
Application Potential ◽  
Thermal Stability Of

Epoxidization is an interesting way to develop a new application of lignin and therefore to improve its application potential. In this work, kraft lignin-based epoxy resins were obtained by the epoxidization reaction, using the kraft lignin recovered directly from pulping liquor and modified by a methylolation reaction. The methylolated lignins were obtained by the reaction of original kraft lignin with formaldehyde and glyoxal, which is a less volatile and less toxic aldehyde. 1H-NMR spectroscopy showed that methylolated kraft lignin has more hydroxymethyl groups than glyoxalated kraft lignin. For the epoxidization reaction we studied the influence of the lignin:NaOH (w/w) ratio, temperature, and time of the reaction on the properties of the prepared epoxidized lignins. The structures of lignin-based epoxy resins were followed by epoxy index test and FTIR spectroscopy. Optimal conditions were obtained for lignin-based epoxy resin produced at lignin/NaOH = 1/3 at 70 ºC for 3h. Thermogravimetry analysis (TGA) revealed that the epoxidization enhances the thermal stability of lignins and may allow a wider temperature range for applications with lignin epoxy-PF blends.

scholarly journals Preparation and characterization of lignin-TiO2 UV-shielding composite material by induced synthesis with nanofibrillated cellulose

BioResources ◽  
2020 ◽  
Vol 15 (4) ◽  
pp. 7374-7389
Author(s):  
Daliang Guo ◽  
Jinmeng Zhang ◽  
Lizheng Sha ◽  
Bei Liu ◽  
Xin Zhang ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Renewable Resources ◽  
Uv Light ◽  
Nanofibrillated Cellulose ◽  
Transmission Spectra ◽  
Uv Shielding ◽  
Uv Visible ◽  
Hand Cream ◽  
Comprehensive Characterization

It is desirable to develop biodegradable ultraviolet (UV)-shielding materials from renewable resources, as the demand for sustainability is ever increasing. In this work, a novel lignin-TiO2 UV-shielding composite was synthesized successfully via a hydrothermal method induced by nanofibrillated cellulose (NFC). Comprehensive characterization showed that the lignin-TiO2@NFC composite induced by NFC had good nanoparticle size, shape, and thermal stability. The sunscreen performance of lignin-TiO2@NFC was investigated via mixture with unmodified hand cream. The UV-visible (vis) transmission spectra results revealed that the unmodified cream with 10 wt% lignin-TiO2@NFC absorbed approximately 90% of UV light in the full UV band (200 nm to 400 nm), which indicated that lignin-TiO2@NFC had a good UV-shielding ability.

scholarly journals Valproic Acid-Induced Changes of 4D Nuclear Morphology in Astrocyte Cells

2021 ◽  
pp. mbc.E20-08-0502
Author(s):  
Alexandr A. Kalinin ◽  
Xinhai Hou ◽  
Alex S. Ade ◽  
Gordon-Victor Fon ◽  
Walter Meixner ◽  
...  
Keyword(s):  
Valproic Acid ◽  
Histone Deacetylase Inhibitors ◽  
Cellular Reprogramming ◽  
Nuclear Morphology ◽  
Size And Shape ◽  
Induced Changes ◽  
Comprehensive Characterization ◽  
Primary Human Astrocyte ◽  
Over Time

Histone deacetylase inhibitors, such as valproic acid (VPA), have important clinical therapeutic and cellular reprogramming applications. They induce chromatin re-organization that is associated with altered cellular morphology. However, there is a lack of comprehensive characterization of VPA-induced changes of nuclear size and shape. Here, we quantify 3D nuclear morphology of primary human astrocyte cells treated with VPA over time (hence, 4D). We compared volumetric and surface-based representations and identified seven features that jointly discriminate between normal and treated cells with 85% accuracy on day 7. From day 3, treated nuclei were more elongated and flattened and then continued to morphologically diverge from controls over time, becoming larger and more irregular. On day 7, most of the size and shape descriptors demonstrated significant differences between treated and untreated cells, including a 24% increase in volume and 6% reduction in extent (shape regularity) for treated nuclei. Overall, we show that 4D morphometry can capture how chromatin re-organization modulates the size and shape of the nucleus over time. These nuclear structural alterations may serve as a biomarker for histone (de-)acetylation events and provide insights into mechanisms of astrocytes-to-neurons reprogramming.

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