Study of the behavior of short chains in print paper subjected to a natural aging

Degradation of paper through time can be measured by monitoring the intensity changes in the band located at 620 nm of its emission fluorescence spectra. The behavior of this band is closely related to the structural stability of the short cellulose chains. A fast degradation of these cellulose chains, mainly lignin, translates in the rapid denaturation of paper occurring at its first aging state. This work proposes a method to reincorporate short cellulose chains in the structure of aged paper through its immersion during 24 h in a solution based on ethyl alcohol and extracts of wood pieces. Results of fluorescence spectra measurements indicate that the short cellulose chains in the solution get embedded in the old paper, making the shape and intensity of the fluorescence emission spectra peaks of new and old paper almost indistinguishable. This behavior provides a desirable approach to analyze, preserve and restore aged paper documents.

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Luminescent Hybrid Materials Based on Curcumin Derivatives Embedded in Palygorskite

Materiale Plastice ◽

10.37358/mp.18.1.4964 ◽

2018 ◽

Vol 55 (1) ◽

pp. 63-67

Author(s):

Monica Florentina Raduly ◽

Valentin Raditoiu ◽

Alina Raditoiu ◽

Luminita Eugenia Wagner ◽

Viorica Amariutei ◽

...

Keyword(s):

Hybrid Materials ◽

Fluorescence Spectra ◽

Fluorescence Emission ◽

Emission Spectra ◽

Hydroxyl Groups ◽

Fluorescent Properties ◽

Fluorescence Emission Spectra ◽

Curcumin Derivatives ◽

Absorption Studies ◽

Inorganic Matrix

The seven curcumin derivatives were deposited on palygorskite in order to obtain hybrid materials. The fluorescence emission spectra of the obtained materials show a decrease in fluorescence intensity relative to the respective dyes, due to the environments around the dyestuff molecules created in the host matrices. Absorption studies show the best adsorption on the inorganic matrix, for the compounds with the hydroxyl groups. Correlating fluorescence spectra of hybrid materials with the results for absorption spectra of the dyes adsorbtion on the surface of the clay lead to the conclusion that a high percentage of the adsorbed dye had the effect of fluorescence quenching. Thus, it was confirmed that the fluorescent properties of hybrid materials depend on the interactions established between the fluorescent dyestuff and the inorganic network.

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Solid state fluorescence of proteins in high throughput mode and its applications

F1000Research ◽

10.12688/f1000research.2-82.v2 ◽

2019 ◽

Vol 2 ◽

pp. 82

Author(s):

Saurabh Gautam ◽

Munishwar N Gupta

Keyword(s):

Solid State ◽

High Throughput ◽

Fluorescence Spectra ◽

Fluorescent Protein ◽

Resonance Energy Transfer ◽

Fluorescence Emission ◽

Resonance Energy ◽

Emission Spectra ◽

Fluorescence Emission Spectra ◽

Simple Method

Direct comparison between fluorescence spectra of a sample in solution and solid state form is valuable to monitor the changes in protein structure when it is “dried” or immobilized on a solid surface (for biocatalysis or sensor applications). We describe here a simple method for recording fluorescence emission spectra of protein powders without using any dedicated accessory for solid samples in a high-throughput format. The 96-well plate used in our studies, was coated black from all the sides and the excitation and emission paths are identical and are from the top of the well. These two features minimize scatter and provide fairly noise free spectra. Even then the fluorescence intensity may be dependent upon many factors such as the extent of protein aggregation, morphology and sizes of the protein particles. Hence, (changes in) λmax emission may be a more reliable metric in the case of fluorescence spectra of proteins in the solid state. However, any large changes in the intensity could indicate changes in the microenvironment of the fluorophore. The fluorescence emission spectra were blue-shifted (4 to 9 nm), showed an increase in the intensity for different proteins studied upon lyophilization, and were similar to what has been reported by others using available commercial accessories for solid state samples. After validating that our method worked just as well as the dedicated accessories, we applied the method to compare the fluorescence emission spectra of α-chymotrypsin in solution, precipitated form, and the lyophilized powder form. We further examined the fluorescence emission spectra of green fluorescent protein (GFP) in solution and solid form. We also analyzed fluorescence resonance energy transfer (FRET) between tryptophan (Trp57) and the cyclic chromophore of GFP. These findings pointed towards the change in the microenvironment around the cyclic chromophore in GFP upon lyophilization.

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Solid state fluorescence of proteins in high throughput mode and its applications

F1000Research ◽

10.12688/f1000research.2-82.v1 ◽

2013 ◽

Vol 2 ◽

pp. 82

Author(s):

Saurabh Gautam ◽

Munishwar N Gupta

Keyword(s):

Solid State ◽

High Throughput ◽

Fluorescence Spectra ◽

Tertiary Structure ◽

Fluorescence Emission ◽

Emission Spectra ◽

Red Shift ◽

Solid Samples ◽

Fluorescence Emission Spectra ◽

Simple Method

A simple method to determine fluorescence emission spectra of proteins in solid state is described. The available commercial accessories can only accommodate solid samples and hence do not allow a direct comparison between fluorescence spectra of a sample in solution and solid state form. Such comparisons are valuable to monitor the changes in protein structure when it is “dried” or immobilized on a solid surface (for biocatalysis or sensor applications). The commercially available accessories also do not allow working in a high throughput mode. We describe here a simple method for recording fluorescence emission spectra of protein powders without using any dedicated accessory for solid samples. This method works with a 96-well plate format. It enables the comparison of fluorescence spectra of a sample in a solid state with solution spectra, using comparable quantities of protein. The fluorescence emission spectra were blue-shifted (4 to 9 nm), showed an increase in the intensity for different proteins studied upon lyophilization, and were similar to what has been reported by others using available commercial accessories for solid state samples. After validating that our method worked just as well as the dedicated accessories, we applied the method to compare the fluorescence emission spectra of α-chymotrypsin in solution, precipitated form and the lyophilized powder form. α-Chymotrypsin in solution showed a λmax of 335 nm while a high-activity preparation of the same enzyme for non-aqueous media, known as enzyme precipitated and rinsed with propanol (EPRP), showed an increase in the intensity of the fluorescence emission spectra. However, there was a small red shift of 2 nm (λmax of 337 nm) in contrast to lyophilized powder which showed a λmax of 328 nm. This is due to a difference in the tertiary structure of the protein as well as the microenvironment of aromatic residues between the two preparations. We further examined the fluorescence emission spectra of green fluorescent protein (GFP) in solution and solid form. The relative fluorescence intensity of lyophilized GFP powder was decreased significantly to 17% as compared to GFP in solution, and showed a red shift of 4 nm in the emission λmax. It was found that fluorescence resonance energy transfer (FRET) between tryptophan (Trp57) and the cyclic chromophore of GFP was significantly diminished. This indicated the change in the microenvironment around the cyclic chromophore in GFP upon lyophilization.

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Synthesis and Optical Properties of some Novel Bis-1,3,4-Oxadiazoles

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1104.131 ◽

2015 ◽

Vol 1104 ◽

pp. 131-135

Author(s):

Hua Liu ◽

Lin Lu ◽

Dun Jia Wang

Keyword(s):

Optical Properties ◽

Fluorescence Spectra ◽

Fluorescence Emission ◽

Chloroform Solution ◽

Emission Spectra ◽

Pyridine Derivatives ◽

Fluorescence Emission Spectra ◽

H Nmr ◽

Uv Illumination ◽

Oxadiazole Derivatives

Three 2,6-bis (1,3,4-oxadiazol-2-yl) pyridine derivatives were synthesized and their structures were conformed by1H NMR, FTIR, MS techniques and elemental analysis. The UV–Vis absorption and fluorescence emission spectra of these compounds were investigated in chloroform solution. The results showed that these bis-1,3,4-oxadiazole derivatives had broad and strong absorption at 278−302 nm in the UV–Vis spectra and exhibited fluorescence emission at 338 −367 nm under UV illumination in fluorescence spectra. It was found that the nature of the substituents at benzene ring in bis-1,3,4-oxadiazole derivatives had a significant impact on their photoluminescence behaviors.

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Lewis acid induced spectral changes of sterically hindered and unhindered meso-tetra(aryl)porphyrins: fluorescence emission spectra

New Journal of Chemistry ◽

10.1039/c9nj06040e ◽

2020 ◽

Vol 44 (7) ◽

pp. 3028-3037

Author(s):

Aida G. Mojarrad ◽

Saeed Zakavi

Keyword(s):

Absorption Spectra ◽

Lewis Acid ◽

Fluorescence Spectra ◽

Fluorescence Emission ◽

Emission Spectra ◽

Molecular Complexes ◽

Fluorescence Emission Spectra ◽

Spectral Changes ◽

Sterically Hindered

Fluorescence spectra of a series of electron-rich and electron-deficient meso-tetra(aryl)porphyrins and their molecular complexes with DDQ, TCNE and BF3 were investigated and compared. In spite of the great resemblance between the absorption spectra of the molecular complexes, large differences were observed between their emission spectra.

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Optical Properties and Zinc Nitride Thin Films Prepared Using Magnetron Reactive Sputtering

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.940.11 ◽

2014 ◽

Vol 940 ◽

pp. 11-15

Author(s):

Jun Qin Feng ◽

Jun Fang Chen

Keyword(s):

Thin Films ◽

Band Gap ◽

Near Infrared ◽

Fluorescence Emission ◽

Emission Spectra ◽

Sem Images ◽

Fluorescence Emission Spectra ◽

Glass Substrates ◽

Zinc Nitride ◽

Direct Band

Zinc nitride films were deposited by ion sources-assisted magnetron sputtering with the use of Zn target (99.99% purity) on 7059 glass substrates. The films were characterized by XRD, SEM and EDS, the results of which show that the polycrystalline zinc nitride thin film can be grown on the glass substrates, the EDS spectrum confirmed the chemical composition of the films and the SEM images revealed that the zinc nitride thin films have a dense structure. Ultraviolet-visible-near infrared spectrophotometer was used to study the transmittance behaviors of zinc nitride thin films, which calculated the optical band gap by Davis Mott model. The results of the fluorescence emission spectra show the zinc nitride would be a direct band gap semiconductor material.

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Stress and Phase Transformation Phenomena in Oxide Films: Real-Time Spectroscopic Measurements

MRS Proceedings ◽

10.1557/proc-271-319 ◽

1992 ◽

Vol 271 ◽

Cited By ~ 3

Author(s):

Gregory J. Exarhos ◽

Nancy J. Hess

Keyword(s):

Phase Transformation ◽

Applied Pressure ◽

Oxide Films ◽

Fluorescence Emission ◽

Emission Spectra ◽

Film Deposition ◽

Optical Methods ◽

Fluorescence Emission Spectra ◽

Line Intensities ◽

Deposition Parameters

ABSTRACTIn situ optical methods are reviewed for characterization of phase transformation processes and evaluation of residual stress in solution-deposited metastable oxide films. Such low density films most often are deposited as disordered phases making them prone to crystallization and attendant densification when subjected to increased temperature and/or applied pressure. Inherent stress imparted during film deposition and its evolution during the transformation are evaluated from phonon frequency shifts seen in Raman spectra (TiO2) or from changes in the laser-induced fluorescence emission spectra for films containing rare earth (Sm+3:Y3Al5O12) or transition metal (Cr+3 :Al2O3) dopants. The data in combination with measured increases in line intensities intrinsic to the evolving phase are used to follow crystallization processes in thin films. In general, film deposition parameters are found to influence the crystallite ingrowth kinetics and the magnitude of stress and stress relaxation in the film during the transformation. The utility of these methods to probe crystallization phenomena in oxide films will be addressed.

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