scholarly journals A microspectrophotometer for UV–visible absorption and fluorescence studies of protein crystals

2002 ◽  
Vol 35 (3) ◽  
pp. 319-326 ◽  
Author(s):  
Dominique Bourgeois ◽  
Xavier Vernede ◽  
Virgile Adam ◽  
Emanuela Fioravanti ◽  
Thomas Ursby
Keyword(s):  
Emission Spectra ◽  
Fluorescent Substrate ◽  
Visible Absorption ◽  
Fluorescence Studies ◽  
Endogenous Fluorophores ◽  
Physico Chemical ◽  
Absorption Studies ◽  
Potential Applications ◽  
Exogenous Fluorophores ◽  
Proper Interpretation

Absorption microspectrophotometry has been shown to be of considerable help to probe crystalline proteins containing chromophores, metal centres, or coloured substrates/co-factors. Absorption spectra contribute to the proper interpretation of crystallographic structures, especially when transient intermediate states are studied. Here it is shown that fluorescence microspectrophotometry might also be used for such purposes if endogenous fluorophores are present in the macromolecule or when exogenous fluorophores are added and either bind to the protein or reside in the solvent channels. An off-line microspectrophotometer that is able to perform low-temperature absorption and fluorescence spectroscopy on crystals mounted in cryo-loops is described. One-shot steady-state emission spectra of outstanding quality were routinely collected from several samples. In some cases, crystals with optical densities that are too low or too high for absorption studies can still be tackled with fluorescence microspectrophotometry. The technique may be used for simple controls such as checking the presence, absence or redox state of a fluorescent substrate/co-factor. Potential applications in the field of kinetic crystallography are numerous. In addition, the possibility to probe key physico-chemical parameters of the crystal, such as temperature, pH or solvent viscosity, could trigger new studies in protein dynamics.

Thermoluminescence, fluorescence, and optical absorption studies on single crystals of rubidium iodide doped with Eu2+

1985 ◽  
Vol 63 (4) ◽  
pp. 517-521 ◽  
Author(s):  
K. L. Tan ◽  
S. Sapru ◽  
S. B. S. Sastry
Keyword(s):  
Optical Absorption ◽  
Emission Spectra ◽  
Energy Band Diagram ◽  
Band Diagram ◽  
Fluorescence Studies ◽  
Fluorescence Measurements ◽  
Absorption Studies ◽  
Order Of Magnitude ◽  
Optical Treatment ◽  
The Eu

Thermoluminescence, optical absorption, and fluorescence studies on the RbI:Eu2+ system indicate that the Eu2+ ions act as donors on irradiation and thereby convert to the Eu3+ ions. On thermal and (or) optical treatment the electrons released are captured back. The integrated light intensity of the system is an order of magnitude higher than that of the undoped samples. Fluorescence measurements show an emission around 2.83 eV. Thermoluminescence emission spectra give two emission bands peaking around 2.48 and 2.83 eV. A tentative energy band diagram is suggested explaining these emissions. Excitation of irradiated samples with F light is used to support this model.

Electrochemical Deposition of Polypyrrole Nanostructures for Energy Applications: A Review

2020 ◽  
Vol 16 (4) ◽  
pp. 462-477 ◽  
Author(s):  
Patrizia Bocchetta ◽  
Domenico Frattini ◽  
Miriana Tagliente ◽  
Filippo Selleri
Keyword(s):  
Lithium Batteries ◽  
High Performance ◽  
Relevant Literature ◽  
Chemical Parameters ◽  
Energy Devices ◽  
Energy Applications ◽  
Physico Chemical ◽  
Potential Applications ◽  
Template Free ◽  
Cathodic Polymerization

By collecting and analyzing relevant literature results, we demonstrate that the nanostructuring of polypyrrole (PPy) electrodes is a crucial strategy to achieve high performance and stability in energy devices such as fuel cells, lithium batteries and supercapacitors. In this critic and comprehensive review, we focus the attention on the electrochemical methods for deposition of PPy, nanostructures and potential applications, by analyzing the effect of different physico-chemical parameters, electro-oxidative conditions including template-based or template-free depositions and cathodic polymerization. Diverse interfaces and morphologies of polymer nanodeposits are also discussed.

Intense multi-state visible absorption and full-color luminescence of nitrogen-doped carbon quantum dots for blue-light-excitable solid-state-lighting

2016 ◽  
Vol 4 (38) ◽  
pp. 9027-9035 ◽  
Author(s):  
Daqin Chen ◽  
Weiwei Wu ◽  
Yongjun Yuan ◽  
Yang Zhou ◽  
Zhongyi Wan ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Solid State ◽  
Carbon Quantum Dots ◽  
Solid State Lighting ◽  
Visible Absorption ◽  
Nitrogen Doped ◽  
Full Color ◽  
Potential Applications ◽  
Doped Carbon Dots ◽  
Nitrogen Doped Carbon

Nitrogen-doped carbon dots with multi-state visible absorption and full-color blue/yellow/red emissions are synthesized, and show potential applications in solid-state-lighting.

scholarly journals Prokaryotic Communities in the Thalassohaline Tuz Lake, Deep Zone, and Kayacik, Kaldirim and Yavsan Salterns (Turkey) Assessed by 16S rRNA Amplicon Sequencing

2021 ◽  
Vol 9 (7) ◽  
pp. 1525
Author(s):  
Can Akpolat ◽  
Ana Beatriz Fernández ◽  
Pinar Caglayan ◽  
Baris Calli ◽  
Meral Birbir ◽  
...  
Keyword(s):  
16S Rrna ◽  
Salt Lake ◽  
Amplicon Sequencing ◽  
Deep Zone ◽  
Biotechnological Potential ◽  
16S Rrna Amplicon Sequencing ◽  
Physico Chemical ◽  
Potential Applications ◽  
A Minor ◽  
Tuz Lake

Prokaryotic communities and physico-chemical characteristics of 30 brine samples from the thalassohaline Tuz Lake (Salt Lake), Deep Zone, Kayacik, Kaldirim, and Yavsan salterns (Turkey) were analyzed using 16S rRNA amplicon sequencing and standard methods, respectively. Archaea (98.41% of reads) was found to dominate in these habitats in contrast to the domain Bacteria (1.38% of reads). Representatives of the phylum Euryarchaeota were detected as the most predominant, while 59.48% and 1.32% of reads, respectively, were assigned to 18 archaeal genera, 19 bacterial genera, 10 archaeal genera, and one bacterial genus that were determined to be present, with more than 1% sequences in the samples. They were the archaeal genera Haloquadratum, Haloarcula, Halorhabdus, Natronomonas, Halosimplex, Halomicrobium, Halorubrum, Halonotius, Halolamina, Halobacterium, and Salinibacter within the domain Bacteria. The genera Haloquadratum and Halorhabdus were found in all sampling sites. While Haloquadratum, Haloarcula, and Halorhabdus were the most abundant genera, two uncultured Tuz Lake Halobacteria (TLHs) 1 and 2 were detected in high abundance, and an additional uncultured haloarchaeal TLH-3 was found as a minor abundant uncultured taxon. Their future isolation in pure culture would permit us to expand our knowledge on hypersaline thalassohaline habitats, as well as their ecological role and biomedical and biotechnological potential applications.

UV-Visible Absorption Studies of Gossypol-Metal Cation Complexes in Acetonitrile Solution

1991 ◽  
Vol 24 (10) ◽  
pp. 1265-1273 ◽  
Author(s):  
Bronislaw Marciniak ◽  
Halina Kozubek ◽  
Bogumil Brzezinski
Keyword(s):  
Metal Cation ◽  
Acetonitrile Solution ◽  
Visible Absorption ◽  
Absorption Studies ◽  
Uv Visible ◽  
Cation Complexes

scholarly journals Luminescent Hybrid Materials Based on Curcumin Derivatives Embedded in Palygorskite

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.

Anatomy of a Natural Sunlight Driven CdS/CoTiO3/ZnO Ternary Photocatalyst for Efficient Optical Properties and Removal of Reactive Orange 30

2021 ◽  
Vol 25 (8) ◽  
pp. 100-109
Author(s):  
G. Divya ◽  
D. Sakthi ◽  
A. Priyadharsan ◽  
S. Boobas ◽  
S. Sivakumar
Keyword(s):  
Electron Transfer ◽  
Photocatalytic Activity ◽  
Potential Gradient ◽  
Spatial Separation ◽  
Morphological Properties ◽  
Photoexcited Electron ◽  
Visible Absorption ◽  
Potential Applications ◽  
The Difference ◽  
Reactive Orange

ZnO as a promising photocatalyst has gained much attention for the removal of organic pollutants from water. However, the main drawbacks of the relatively low photocatalytic activity and high recombination rate of photoexcited electron-hole pairs restrict its potential applications. Promoting the spatial separation of photoexcited charge carriers is of paramount significance for photocatalysis because the difference in the band positions makes the potential gradient at the composite boundary. In this work, binary CdS/ZnO and CoTiO3/ZnO are first prepared by dispersion method and then decorated with ZnO particles to construct CdS/CoTiO3/ZnO ternary composites. For this reason, the CdS/CoTiO3/ZnO ternary composites was effectively designed and analyzed for the crystalline structure, light absorption, photoexcitation behavior and surface morphological properties by X-ray diffraction, diffuse reflectance UV/visible absorption spectroscopy, photoluminescence spectroscopy and scanning electron micrograph respectively. The photocatalytic activity was examined by degradation of the dye solution spectrophotometrically. The results of photocatalytic degradation indicated that the CdS/CoTiO3/ZnO ternary composites are much higher than those of bare CdS, CoTiO3, ZnO and any binary composites such as CoTiO3/ZnO and ZnO/CdS. The enhanced activity could be attributed to the drop electron transfer from CdS to ZnO to CoTiO3 through the interfacial potential gradient in the ternary hybrid conduction bands. The enhanced electron transfer of CdS/CoTiO3/ZnO ternary composites was also applicable to degrade other reactive dyes.

scholarly journals Preparation and Characterization of Montmorillonite/PEDOT-PSS and Diatomite/PEDOT-PSS Hybrid Materials. Study of Electrochemical Properties in Acid Medium

2020 ◽  
Vol 4 (2) ◽  
pp. 51 ◽  
Author(s):  
Mohamed Kiari ◽  
Raúl Berenguer ◽  
Francisco Montilla ◽  
Emilia Morallón
Keyword(s):  
Electron Transfer ◽  
Electrochemical Properties ◽  
Hybrid Materials ◽  
Environmental Remediation ◽  
Electroactive Material ◽  
Physico Chemical ◽  
Emerging Pollutant ◽  
Transfer Capability ◽  
Potential Applications ◽  
Concentration Sensitivity

The hybridization of clay minerals with conducting polymers receives great interest for different potential applications, including environmental remediation. This work studies and compares the electrochemical properties of two different clays, montmorillonite (Mont) and diatomite (Diat), and their respective clay/PEDOT-PSS hybrid materials in H2SO4 medium. The hybrid materials were prepared by electropolymerization of EDOT in the presence of PSS. The physico-chemical and electrochemical properties of both clays were analyzed by different techniques, and the influence of the clay properties on electropolymerization and the electroactivity of the resulting clay/PEDOT-PSS hybrids was investigated. Specifically, the Fe2+/Fe3+ redox probe and the oxidation of diclofenac, as a model pharmaceutical emerging pollutant, were used to test the electron transfer capability and oxidative response, respectively, of the clay/PEDOT-PSS hybrids. The results demonstrate that, despite its low electrical conductivity, the Mont is an electroactive material itself with good electron-transfer capability. Conversely, the Diat shows no electroactivity. The hybridization with PEDOT generally enhances the electroactivity of the clays, but the clay properties affect the electropolymerization efficiency and hybrids electroactivity, so the Mont/PEDOT displays improved electrochemical properties. It is demonstrated that clay/PEDOT-PSS hybrids exhibit diclofenac oxidation capability and diclofenac concentration sensitivity.

scholarly journals Structures, physico-chemical properties, production and (potential) applications of sucrose-derived α-d-glucans synthesized by glucansucrases

2020 ◽  
Vol 249 ◽  
pp. 116818
Author(s):  
Xiaodan Li ◽  
Xiaofei Wang ◽  
Xiangfeng Meng ◽  
Lubbert Dijkhuizen ◽  
Weifeng Liu
Keyword(s):  
Chemical Properties ◽  
Physico Chemical ◽  
Potential Applications

Potential Applications of Biphosphonates in Dental Surgical Implants

2007 ◽  
Vol 20 (3) ◽  
pp. 455-465 ◽  
Author(s):  
D. Berardi ◽  
T. Carlesi ◽  
F. Rossi ◽  
M. Calderini ◽  
R. Volpi ◽  
...  
Keyword(s):  
Alveolar Bone ◽  
Chemical Properties ◽  
Osteonecrosis Of The Jaw ◽  
In Vivo Experiments ◽  
Surgical Implants ◽  
Physico Chemical ◽  
Potential Applications ◽  
Collateral Effect

Biphosphonates are largely used for their unquestionable properties of inhibiting bone resorption by osteoclast in the treatment of various osteometabolic illnesses such as osteoporosis, multiple myeloma, tumors which metastasize to the bone and malignant hypercalcemia. In this literature review the physico-chemical properties, biologic activities and the mechanisms of action of biphosphonates are described. The use of these drugs is discussed, analyzing the quantity of results which have emerged through in vitro and in vivo experiments on animal models. In this study the efficiency of these drugs is demonstrated in contrasting the osteolitic processes of the alveolar bone, in promoting the neoformation and in bettering the quality of bone implants. However, it is important to draw attention to a worrying correlation which has emerged during the last 3–4 years, between osteonecrosis of the jaw (ONJ) and the systemic administration of aminobiphosphonates. This collateral effect did not emerge following the use of non-aminobiphosphonates. The aim of this revie w is to identify the guidelines for the use of biphosphonates in oral implant surgery.

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