Search results for "FTIR"
showing 10 items of 146 documents
Role of residual water hydrogen bonding in sugar/water/biomolecule systems: a possible explanation fortrehalose peculiarity
2007
We report on the set of experimental and simulative evidences which enabled us to suggest how biological structures embedded in a non-liquid water–saccharide solvent are anchored to the surrounding matrix via a hydrogen bond network. Such a network, whose rigidity increases by decreasing the sample water content, couples the degrees of freedom of the biostructure to those of the matrix and gives place to protein–saccharide–water structures (protein–solvent conformational substates). In particular, the whole set of data evidences that, while the protein–sugar interaction is well described in terms of a water entrapment hypothesis, the water replacement hypothesis better describes the sugar–m…
Spectroscopic and microscopic characterization of BSA hydrogels: towards new biomaterials
2014
The water association band as a marker of hydrogen bonds in trehalose amorphous matrices
2017
The relevant role played by residual water in modulating the dynamics and structure of a protein, a matrix and their coupling has been thoroughly studied in bioprotective amorphous saccharide matrices via experiments and simulations. In order to better characterize this residual water and the hydrogen bond structures in which it is involved, in this work infrared spectroscopy experiments are conducted on trehalose-water systems. The properties of water are inferred from the study of a peculiar infrared band, the water association band, which we exploited as a marker of the hydrogen bonds in which water is involved. Our aim was the identification of populations of water molecules, which give…
Polikaprolaktona nanošķiedru izgatavošana un raksturojums, izmantojot elektrovērpšanas metodi šūnu/ biotehnoloģiju pielietojumiem
2022
Polikaprolaktons ir sintētisks polimērs, kuru plaši izmanto tā zemo izmaksu, pieejamības, fizikālo un bioloģisko īpašību dēļ. No šī materiāla izgatavotās nanošķiedras lieto un turpina pētīt biotehnoloģijas un bioinženierijas jomās. Bakalaura darba mērķis bija izstrādāt polikaprolaktona nanošķiedru matricas cilvēka ādas šūnu kultivēšanai un novērtēt to izmantošanas iespēju biotehnoloģijas jomā. Darba gaitā tika izgatavotas polikaprolaktona membrānas ar elektrovērpšanas metodi. Skenējošā elektronu mikroskopija tika izmantota, lai raksturotu morfoloģiju, savukārt, ar Furjē transformācijas infrasarkano spektroskopiju tika noteikta ķīmiskā tīrība. Uz membrānām tika uzsētas cilvēka ādas šūnas un …
Pressure effects on α-synuclein amyloid fibrils: An experimental investigation on their dissociation and reversible nature
2017
αâsynuclein amyloid fibrils are found in surviving neurons of Parkinson's disease affected patients, but the role they play in the disease development is still under debate. A growing number of evidences points to soluble oligomers as the major cytotoxic species, while insoluble fibrillar aggregates could even play a protection role. In this work, we investigate αâsynuclein fibrils dissociation induced at high pressure by means of Small Angle X-ray Scattering and Fourier Transform Infrared Spectroscopy. Fibrils were produced from wild type αâsynuclein and two familial mutants, A30P and A53T. Our results enlighten the different reversible nature of αâsynuclein fibrils fragmentati…
Volframa pārklājumu termiska modificēšana detektēšanai ar infrasarkanās spektrometrijas metodi
2022
Volframa pārklājumu termiska modificēšana detektēšanai ar infrasarkanās spektrometrijas metodi. Goldmane A. E., zinātniskā vadītāja, pētniece, Avotiņa L. Bakalaura darbs, 36 lpp, 15 attēli, 4 tabulas, 56 literatūras avoti, 6 pielikumi. Latviešu valodā. Pusvadītāju tehnoloģijas mūsdienās lieto dažāda veida elektronikai. Materiālu atbilstību parametriem nosaka ražošanas gaitā – nepieciešams izstrādāt metodoloģiju to izvērtēšanai. Darbā veikta uz silīcija (Si) – silīcija dioksīda (SiO2) pamatnes sintezēta volframa (W) pārklājumu termiska modificēšana un izpēte ar FTIR, XRD, SEM-EDS metodi. Modificētu pārklājumu spektros ir papildus signāli 700-900 cm-1, kas attiecināmi uz W-skābekļa saitēm; kr…
Protection of living yeast cells by micro-organized shells of natural polyelectrolytes
2015
International audience; Saccharomyces cerevisiae, a eukaryotic model organism, plays a key role in the oxidative stability of fermented products. In order to protect cells against environmental stresses, we report a method of modifying the cell surface architecture while maintaining the internal working properties of the system. The objective was to encapsulate living yeast cells in micro-organized polyelectrolyte shells using layer-by-layer (LbL) assembly. For the first time, the natural polyelectrolytes, β-lactoglobulin and sodium alginate, were alternately deposited on the surface of S. cerevisiae. Transmission electron microscopy coupled with immune-cytochemistry and scanning electron m…
Tolerance, Adaptation, and Cell Response Elicited by Micromonospora sp. Facing Tellurite Toxicity: A Biological and Physical-Chemical Characterization
2022
The intense use of tellurium (Te) in industrial applications, along with the improper disposal of Te-derivatives, is causing their accumulation in the environment, where oxyanion tellurite (TeO32−) is the most soluble, bioavailable, and toxic Te-species. On the other hand, tellurium is a rare metalloid element whose natural supply will end shortly with possible economic and technological effects. Thus, Te-containing waste represents the source from which Te should be recycled and recovered. Among the explored strategies, the microbial TeO32− biotransformation into less toxic Te-species is the most appropriate concerning the circular economy. Actinomycetes are ideal candidates in…
Diorganotin(IV) N-acetyl-L-cysteinate complexes: synthesis, solid state, solution phase, DFT and biological investigations.
2009
Diorganotin(IV) complexes of N-acetyl-L-cysteine (H(2)NAC; (R)-2-acetamido-3-sulfanylpropanoic acid) have been synthesized and their solid and solution-phase structural configurations investigated by FTIR, Mössbauer, (1)H, (13)C and (119)Sn NMR spectroscopy. FTIR results suggested that in R(2)Sn(IV)NAC (R = Me, Bu, Ph) complexes NAC(2-) behaves as dianionic tridentate ligand coordinating the tin(IV) atom, through ester-type carboxylate, acetate carbonyl oxygen atom and the deprotonated thiolate group. From (119)Sn Mössbauer spectroscopy it could be inferred that the tin atom is pentacoordinated, with equatorial R(2)Sn(IV) trigonal bipyramidal configuration. In DMSO-d(6) solution, NMR spectr…
Bioaccumulation of Trace Elements from Aqueous Solutions by Selected Terrestrial Moss Species
2022
The interrelationship between metal concentrations in mosses and their surroundings prompts research toward examining their accumulation properties, as it is particularly important for their usage in biomonitoring studies that use mosses. In this study, the kinetics of elemental sorption in three moss species (Pleurozium schreberi, Dicranum polysetum, and Sphagnum fallax) were investigated under laboratory conditions. Sorption from metal salt solutions was carried out under static conditions with decreasing elemental concentration. Functional groups responsible for binding metal cations to the internal structures of the mosses were also identified. It was shown that the equilibrium state wa…