Search results for "spektroskopia"
showing 10 items of 196 documents
Enhanced quantification of wollastonite and calcite in limestone using fluorescence correction based on continuous wavelet transformation for Raman
2020
Raman spectroscopy offers a nondestructive means to identify minerals in rocks, but the ability to use the technology for quantitative mineralogical analysis is limited by fluorescence that can mask the spectral features of minerals. In this paper we apply continuous wavelet transformation (CWT) to remove fluoresence from Raman data acquired from 26 carbonate rock samples. We then record the intensity values of individual spectral features, proxies for mineral abundances, using the original Raman data and the thus inferred CWT data. The intensity values are then compared against the known mineral abundances determined using the scanning electron microscope (SEM) technology. This comparison …
Spectroscopic method to study low charge state ion and cold electron population in ECRIS plasma
2018
The results of optical emission spectroscopy experiments probing the cold electron population of a 14 GHz Electron Cyclotron Resonance Ion Source (ECRIS) are reported. The study has been conducted with a high resolution spectrometer and data acquisition setup developed specifically for the diagnostics of weak emission line characteristic to ECRIS plasmas. The optical emission lines of low charge state ions and neutral atoms of neon have been measured and analyzed with the line-ratio method. The aforementioned electron population temperature of the cold electron population (Te < 100 eV) is determined for Maxwell-Boltzmann and Druyvesteyn energy distributions to demonstrate the applicability …
Site-by-site tracking of signal transduction in an azidophenylalanine-labeled bacteriophytochrome with step-scan FTIR spectroscopy
2021
Signal propagation in photosensory proteins is a complex and multidimensional event. Unraveling such mechanisms site-specifically in real time is an eligible but a challenging goal. Here, we elucidate the site-specific events in a red-light sensing phytochrome using the unnatural amino acid azidophenylalanine, vibrationally distinguishable from all other protein signals. In canonical phytochromes, signal transduction starts with isomerization of an excited bilin chromophore, initiating a multitude of processes in the photosensory unit of the protein, which eventually control the biochemical activity of the output domain, nanometers away from the chromophore. By implementing the label in pri…
Transient IR spectroscopy identifies key interactions and unravels new intermediates in the photocycle of a bacterial phytochrome.
2020
Phytochromes are photosensory proteins in plants, fungi, and bacteria, which detect red- and far-red light. They undergo a transition between the resting (Pr) and photoactivated (Pfr) states. In bacterial phytochromes, the Pr-to-Pfr transition is facilitated by two intermediate states, called Lumi-R and Meta-R. The molecular structures of the protein in these states are not known and the molecular mechanism of photoconversion is not understood. Here, we apply transient infrared absorption spectroscopy to study the photocycle of the wild-type and Y263F mutant of the phytochrome from Deinococcus radiodurans (DrBphP) from nanoto milliseconds. We identify two sequentially forming Lumi-R states …
Modulation of Structural Heterogeneity Controls Phytochrome Photoswitching
2019
Phytochromes sense red/far-red light and control many biological processes in plants, fungi, and bacteria. Although crystal structures of dark and light adapted states have been determined, the molecular mechanisms underlying photoactivation remains elusive. Here we demonstrate that the conserved tongue region of the PHY domain of a 57kDa photosensory module of Deinococcus radiodurans phytochrome, changes from a structurally heterogeneous dark state to an ordered light activated state. The results were obtained in solution by utilizing a laser-triggered activation approach detected on the atomic level with high-resolution protein NMR spectroscopy. The data suggest that photosignaling of phy…
Structural, Thermoanalytical and Molecular Modeling Studies on N-(3-hydroxypropyl) 3a,12a-Dihydroxy-5b-cholan-24-amide and Its Monohydrates
2007
The synthetic method for preparing N-(3-hydroxypropyl) 3 alpha,12 alpha-dihydroxy-5 beta-cholan-24-amide can lead to formation of at least three different crystal forms - an anhydrous compound and two monohydrates. The structural and thermal properties of these forms have been characterized by 13C-CP/MAS-NMR and IR spectroscopy, thermo- gravimetry, differential scanning calorimetry and by powder and single crystal x-ray crystallography. In addition, theoretical 13C-NMR chemical shift calculations were also performed for the anhydrous compound and for the first monohydrate, starting from single crystal structures and the structures of these species have now been verified. The first monohydra…
Hyper-CEST NMR of metal organic polyhedral cages reveals hidden diastereomers with diverse guest exchange kinetics.
2022
AbstractGuest capture and release are important properties of self-assembling nanostructures. Over time, a significant fraction of guests might engage in short-lived states with different symmetry and stereoselectivity and transit frequently between multiple environments, thereby escaping common spectroscopy techniques. Here, we investigate the cavity of an iron-based metal organic polyhedron (Fe-MOP) using spin-hyperpolarized 129Xe Chemical Exchange Saturation Transfer (hyper-CEST) NMR. We report strong signals unknown from previous studies that persist under different perturbations. On-the-fly delivery of hyperpolarized gas yields CEST signatures that reflect different Xe exchange kinetic…
High-precision measurements of the hyperfine structure of cobalt ions in the deep ultraviolet range
2023
Scientific reports 13(1), 4783 (2023). doi:10.1038/s41598-023-31378-1
Tietokoneistettu NMR-spektroskopia : uuden sukupolven käyttöliittymä ja spektrianalyysi
2017
Korkean resoluution NMR-spektroskopia eroaa muista molekyylispektroskopioista siinä, että jopa kaikkein monimutkaisimmat, tuhansista yksittäisistä spektriviivoista muodostuvat spektrit voidaan esittää vain muutaman parametrin avulla käyttämällä kvanttimekaanista teoriaa. Tietokoneistetun NMR-spektrianalyysin tarkoituksena on määrittää nämä parametrit havaitusta spektristä kvanttimekaanisen spektrianalyysin (QMSA) avulla. Tutkielmassa käydään läpi tietokoneistetun NMR-spektroskopian taustahistoriaa ja teoriaa sekä sivutaan sen eri käyttökohteita. Tutkielman kokeellisessa osassa luotiin käyttöliittymä (ChemAdder) tietokoneistettuun NMR-spektroskopiaan erikoistuneeseen tietokoneohjelmaan, joka…
Disentangling decaying isomers and searching for signatures of collective excitations in β decay
2019
6 pags., 3 figs., 1 tab. -- 27th International Nuclear Physics Conference (INPC2019) 29 July - 2 August 2019, Glasgow, UK