Search results for "ftir"

Sun radiation and temperature impact at different periods of the year on the photooxidation of polyethylene films

2017

Analysis of the IR spectra of weathered films exposed at different periods of the year reveals that, the main regions of the IR spectrum affected by solar irradiation and temperature variation are the complex carbonyls and unsaturations composite absorption bands. Their respective kinetics vary in different manner according to the period at which the exposure is started. Curve fitting has been performed to refine the analysis of the IR spectra and to identify all the chemical species constituting the complex absorption bands. The analysis of the results let appears that whatever the exposure period of the year is, it does not affect the type of developing products, but it has strong effect …

Probing ensemble polymorphism and single aggregate structural heterogeneity in insulin amyloid self-assembly.

2020

Ensembles of protein aggregates are characterized by a nano- and micro-scale heterogeneity of the species. This diversity translates into a variety of effects that protein aggregates may have in biological systems, both in connection to neurodegenerative diseases and immunogenic risk of protein drug products. Moreover, this naturally occurring variety offers unique opportunities in the field of protein-based biomaterials. In the above-mentioned fields, the isolation and structural analysis of the different amyloid types within the same ensemble remain a priority, still representing a significant experimental challenge. Here we address such complexity in the case of insulin for its relevance…

ATR-FTIR spectroscopy for the routine quality control of exosome isolations

2021

Abstract Exosomes are nanosized vesicles containing specific cargos of DNA, RNA, proteins, metabolites, and intracellular and membrane lipids. Exosome isolation needs to be optimized carefully depending on the type of biofluid and tissue and the retrieved exosomes need to be characterized. The main objective of this study was to determine the feasibility of a multimodal analysis of Attenuated Total Reflectance – Fourier Transform Infrared (ATR-FTIR) spectroscopy and UPLC–QqTOF-MSMS for the development of a routine quality control tool of isolated exosomes and the rapid characterization of their lipid profiles and total protein content. Using human milk as model example, exosomes were isolat…

High resolution spectroscopy and the first global analysis of the Tetradecad region of methane 12CH4.

2013

We present the first detailed analysis of the infrared spectrum of methane (12)CH4 in the so-called Tetradecad region from 2.1 to 1.6 μm (4760-6250 cm(-1)). New experimental high resolution FTIR spectra at 78 K and at room temperature combined with improved theoretical modeling have allowed quantum assignments to be greatly extended in this region. A global fit of all assigned lines of (12)CH4 in the 0-6200 cm(-1) region has been performed. In the end, 3012 line positions and 1387 intensities of 45 individual subbands of the Tetradecad were modeled up to J = 14. The root mean square deviations were 0.023 cm(-1) for line positions and 13.86% for line intensities in the Tetradecad region itse…

Development of Methods for the Classification of Vegetable Oils According to Their Botanical Origin

2012

The aim of this work was to construct an LDA model able to classify vegetable oils according to their botanical origin using FTIR spectroscopy data. Also, FTIR data treatment by MLR was used to detect and quantify EVOO adulteration with other low cost edible oils. For these purposes, the vegetable oils shown in Table 5.1 were used. The FTIR spectra of these 30 oil samples were then measured. In all cases, at least two spectra were recorded for each sample. As indicated in this table, four samples of each botanical origin were used to construct a training set in the classification studies, while the remaining samples of each category were employed to evaluate the prediction capability of the…

Thermal aggregation of glycated bovine serum albumin

2010

International audience; Aggregation and glycation processes in proteins have a particular interest in medicine fields and in food technology. Serum albumins are model proteins which are able to self-assembly in aggregates and also sensitive to a non-enzymatic glycation in cases of diabetes. In this work, we firstly reported a study on the glycation and oxidation effects on the structure of bovine serum albumin (BSA). The experimental approach is based on the study of conformational changes of BSA at secondary and tertiary structures by FTIR absorption and fluorescence spectroscopy, respectively. Secondly, we analysed the thermal aggregation process on BSA glycated with different glucose con…

Vieglo stabilo izotopu attiecību pētījumi humusvielu veida un izcelsmes raksturošanai

2019

Vieglо stаbilо izоtоpu аttiecību pētījumi humusvielu veidа un izcelsmes rаksturоšаnаi. Petuhоvа О., zinātniskаis vаdītājs prоf., Dr. chem. Vīksnа А., 61 lаppuses, 25 аttēli, 3 tаbulаs, 64 literаtūrаs аvоti. Lаtviešu vаlоdā. Mаģistrа dаrbа ietvаrоs tikа izpētītа аttiecīgā zinātniskā, metоdiskā un mācību literаtūrа pаr humusvielām un tо izdаlīšаnаs metоdēm, izmаntоšаnаs iespējām. Tikа аnаlizēti humīnskābju un fulvоskābju pаrаugi, kаs izdаlīti nо Eipurа purvа dаžādiem dziļumiem. Humusvielām, lietоjоt vieglо stаbilо izоtоpu аttiecību mаsspektrоmetriju, nоteicа δ13C un δ15N. Izmаntоjоt FTIR-АTR, KBr, DRIFT un PАS, humusvielu IS spektri tikа uzņemti un аnаlizēti.

Bazīdijsēņu micēlija biomasas ieguve biopolimēru hitozāna  un hitīna ekstraģēšanai

2022

Šobrīd pasaulē tiek pievērsta liela uzmanība hitozāna lietošanai pārtikā, biomedicīnā un lauksaimniecībā, kā arī iespēja ar to aizvietot kaitīgas ķīmiskās vielas. Darbā tiek pētīti piemērotākie sēņu kultivēšanas parametri, lai rezultātā iegūtu pēc iespējas lielāku biomasas daudzumu. Kā arī aplūkots jautājums, kura no darbā minētajām bazīdijsēnēm, būtu piemērotākā turpmākajam darbam ar hitozāna izdalīšanu un pielietošanu olu kastu mitruma izturības pastiprināšanā, kura vietā šobrīd izmanto putu polistirola kastes vai kartona kastes, kas ir apstrādātas ar ķīmiskajām vielām. Tika novērots, ka piemērotākā bazīdijsēne, no kuras tiek iegūts lielākais biomasas daudzums, kā arī lielākais hitozāna Ⅱ…

Spectroscopic and microscopic characterization of BSA hydrogels: towards new biomaterials

2014

Nouvelles perspectives concernant la structure et la fonction du domaine carboxyl terminal de Hfq

2015

Accumulating evidence indicates that RNA metabolism components assemble into supramolecular cellular structures to mediate functional compartmentalization within the cytoplasmic membrane of the bacterial cell. This cellular compartmentalization could play important roles in the processes of RNA degradation and maturation. These components include Hfq, the RNA chaperone protein, which is involved in the post-transcriptional control of protein synthesis mainly by the virtue of its interactions with several small regulatory ncRNAs (sRNA). The Escherichia coli Hfq is structurally organized into two domains. An N-terminal domain that folds as strongly bent β-sheets within individual protomers to…