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Spectral Analysis

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https://www.readbyqxmd.com/read/28646686/eeg-spectral-analysis-as-a-putative-early-prognostic-biomarker-in-nondemented-amyloid-positive-subjects
#1
Alida A Gouw, Astrid M Alsema, Betty M Tijms, Andreas Borta, Philip Scheltens, Cornelis J Stam, Wiesje M van der Flier
We studied whether electroencephalography (EEG)-derived measures of brain oscillatory activity are related to clinical progression in nondemented, amyloid positive subjects. We included 205 nondemented amyloid positive subjects (63 subjective cognitive decline [SCD]; 142 mild cognitive impairment [MCI]) with a baseline resting-state EEG data and ≥1-year follow-up. Peak frequency and relative power of 4 frequency bands were calculated. Relationships between normalized EEG measures and time to clinical progression (conversion from SCD to MCI/dementia or from MCI to dementia) were analyzed using Cox proportional hazard models...
June 1, 2017: Neurobiology of Aging
https://www.readbyqxmd.com/read/28646682/sensing-nadh-conformation-using-phasor-analysis-on-fluorescence-spectra
#2
Dylan Palo, Jeff Maltas, Laxmi Risal, Paul Urayama
Phasor analysis on fluorescence signals is a sensitive approach for analyzing multicomponent systems. Initially developed for time-resolved measurements, a spectral version has been used for the rapid identification of regions during the spectral imaging of biological systems. Here we show that quantitative information regarding conformation can be obtained from phasor analysis of fluorescence spectrum shape. Methanol denaturation of NADH and NADH binding to various dehydrogenase proteins are used as model reactions...
June 8, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28646658/investigation-and-structural-elucidation-of-a-new-impurity-in-bulk-drug-of-cilostazol-by-lc-ms-ms-ft-ir-and-nmr
#3
Zhaoxia Hu, Sanguo Gao, Jue Gao
A new impurity was detected in bulk cilostazol (CIL) crude during routine analysis. The impurity (∼4%, the specification for unknown impurity in crude is not more than 0.20%) has a relative retention time of 1.46. Based on MS, NMR and IR spectral data, the impurity was identified as 6,6'-bis(4-(1-cyclohexyl-1H-tetrazol-5-yl) butoxy)-3,3',4,4'-tetrahydro-[7,7'-biquinoline]-2,2'(1H,1'H)-dione(CIL-dimer). The precursor of CIL-dimer is an oxidative product of starting material 6-Hydroxy-3,4-dyhydro-1H-quinolin-2-one(6-HQ), CIL-dimer was formed in the following reaction with 5-(3-Chloro-propyl)-1-cyclohexyl-1H-tetrazol(CHCBT)...
June 15, 2017: Journal of Pharmaceutical and Biomedical Analysis
https://www.readbyqxmd.com/read/28646301/random-initialisation-of-the-spectral-variables-an-alternate-approach-for-initiating-multivariate-curve-resolution-alternating-least-square-mcr-als-analysis
#4
Keshav Kumar
Multivariate curve resolution alternating least square (MCR-ALS) analysis is the most commonly used curve resolution technique. The MCR-ALS model is fitted using the alternate least square (ALS) algorithm that needs initialisation of either contribution profiles or spectral profiles of each of the factor. The contribution profiles can be initialised using the evolve factor analysis; however, in principle, this approach requires that data must belong to the sequential process. The initialisation of the spectral profiles are usually carried out using the pure variable approach such as SIMPLISMA algorithm, this approach demands that each factor must have the pure variables in the data sets...
June 23, 2017: Journal of Fluorescence
https://www.readbyqxmd.com/read/28646299/effective-combined-water-and-sideband-suppression-for-low-speed-tissue-and-in-vivo-mas-nmr
#5
Yalda Liaghati Mobarhan, Jochem Struppe, Blythe Fortier-McGill, André J Simpson
High-resolution magic angle spinning (HR-MAS) NMR is a powerful technique that can provide metabolic profiles and structural constraints on intact biological and environmental samples such as cells, tissues and living organisms. However, centripetal force from fast spinning can lead to a loss of sample integrity. In analyses focusing on structural organization, metabolite compartmentalization or in vivo studies, it is critical to keep the sample intact. As such, there is growing interest in slow spinning studies that preserve sample longevity...
June 23, 2017: Analytical and Bioanalytical Chemistry
https://www.readbyqxmd.com/read/28646267/quantitative-eeg-metrics-differ-between-outcome-groups-and-change-over-the-first-72%C3%A2-h-in-comatose-cardiac-arrest-patients
#6
Sara Leingang Wiley, Babak Razavi, Prashanth Krishnamohan, Michael Mlynash, Irina Eyngorn, Kimford J Meador, Karen G Hirsch
BACKGROUND: Forty to sixty-six percent of patients resuscitated from cardiac arrest remain comatose, and historic outcome predictors are unreliable. Quantitative spectral analysis of continuous electroencephalography (cEEG) may differ between patients with good and poor outcomes. METHODS: Consecutive patients with post-cardiac arrest hypoxic-ischemic coma undergoing cEEG were enrolled. Spectral analysis was conducted on artifact-free contiguous 5-min cEEG epochs from each hour...
June 23, 2017: Neurocritical Care
https://www.readbyqxmd.com/read/28645097/raman-spectroscopy-differentiates-between-sensitive-and-resistant-multiple-myeloma-cell-lines
#7
Domenico Franco, Sebastiano Trusso, Enza Fazio, Alessandro Allegra, Caterina Musolino, Antonio Speciale, Francesco Cimino, Antonella Saija, Fortunato Neri, Marco S Nicolò, Salvatore P P Guglielmino
Current methods for identifying neoplastic cells and discerning them from their normal counterparts are often nonspecific and biologically perturbing. Here, we show that single-cell micro-Raman spectroscopy can be used to discriminate between resistant and sensitive multiple myeloma cell lines based on their highly reproducible biomolecular spectral signatures. In order to demonstrate robustness of the proposed approach, we used two different cell lines of multiple myeloma, namely MM.1S and U266B1, and their counterparts MM...
June 15, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28644563/gas-phase-dissociation-study-of-erythrinian-alkaloids-by-electrospray-ionization-mass-spectrometry-and-computational-methods
#8
T Guaratini, L G P Feitosa, D B Silva, N P Lopes, J L C Lopes, R Vessecchi
Alkaloids from plants of the genus Erythrina display important biological activities, including anxiolytic action. Characterization of these alkaloids by mass spectrometry (MS) has contributed to the construction of a spectral library, has improved understanding of their structures, and has supported the proposal of fragmentation mechanisms in light of density functional calculations (DFT). In this study, we have used low- and high-resolution MS(n) analyses to investigate the fragmentation patterns of erythrinian alkaloids; we have employed the B3LYP/6-31+G(d,p) model to obtain their reactive sites...
June 23, 2017: Journal of Mass Spectrometry: JMS
https://www.readbyqxmd.com/read/28644528/a-systematic-1-h-and-13-c-nmr-spectral-analysis-of-bicyclo-n-3-1-alkanone-systems-determination-of-the-relative-configuration-of-the-stereogenic-centres-and-conformation-of-the-six-membered-ring
#9
Giorgio Giorgi, Pilar López-Alvarado, J Carlos Menéndez
No abstract text is available yet for this article.
June 23, 2017: Magnetic Resonance in Chemistry: MRC
https://www.readbyqxmd.com/read/28644511/bacteriophage-tail-tube-assembly-studied-by-proton-detected-4d-solid-state-nmr
#10
Maximilian Zinke, Pascal Fricke, Camille Samson, Songhwan Hwang, Joseph Wall, Sascha Lange, Sophie Zinn-Justin, Adam Lange
Obtaining unambiguous resonance assignments remains a major bottleneck in solid-state NMR studies of protein structure and dynamics. Particularly for supramolecular assemblies with large subunits (>150 residues), the analysis of crowded spectral data presents a challenge, even if three-dimensional (3D) spectra are used. Here, we present a proton-detected 4D solid-state NMR assignment procedure that is tailored for large assemblies. The key to recording 4D spectra with three indirect carbon or nitrogen dimensions with their inherently large chemical shift dispersion lies in the use of sparse non-uniform sampling (as low as 2%)...
June 23, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28643834/understanding-the-remarkable-luminescence-enhancement-via-sio2-coating-on-tio2-eu-3-nanofibers
#11
Meiqi Chang, Yanhua Song, Ye Sheng, Jie Chen, Haifeng Zou
TiO2:Eu(3+) nanofibers diameters can be tuned by changing the mixed solvent ratio are synthesized via the electrospinning technique. Concentration quenching phenomena and the relationship of the PL intensity ratio I((5)D0-(7)F2)/I((5)D0-(7)F1) with the Eu doping concentration are discussed. Notably, the luminescence intensity is enhanced by about 7.8 fold by coating SiO2 gel layer on the TiO2:Eu(3+) nanofibers, which is successfully performed via a sol-gel process followed by calcination. Furthermore, these fibers are characterized systematically via X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-vis diffuse reflectance spectroscopy (UV-vis DRS), Fourier transform infrared spectroscopy (FT-IR), and photoluminescence (PL) spectroscopy...
June 23, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28643709/comparison-of-central-corneal-thickness-with-four-noncontact-devices-an-agreement-analysis-of-swept-source-technology
#12
Erhan Ozyol, Pelin Özyol
PURPOSE: The purpose of this study was to compare the central corneal thickness (CCT) measurements of four noncontact devices in healthy eyes. MATERIALS AND METHODS: In a sample of 45 healthy controls, CCT was measured using an optical biometer (IOLMaster 700) based on swept-source optical coherence tomography (SS-OCT), high-resolution rotating Scheimpflug camera system (Pentacam HR), spectral-domain OCT (SD-OCT) device with an anterior segment module (Spectralis), and noncontact pachymetry (NCP) device (Topcon TRK-2P)...
June 2017: Indian Journal of Ophthalmology
https://www.readbyqxmd.com/read/28643516/untargeted-comprehensive-two-dimensional-liquid-chromatography-coupled-with-high-resolution-mass-spectrometry-analysis-of-rice-metabolome-using-multivariate-curve-resolution
#13
Meritxell Navarro-Reig, Joaquim Jaumot, Anna Baglai, Gabriel Vivó-Truyols, Peter J Schoenmakers, Romà Tauler
In this work, a new strategy for the chemometric analysis of LC×LC-HRMS data is proposed. This approach consists of a preliminary compression step along the MS spectral dimension based on the selection of the Regions of Interest (ROI), followed by a further data compression along the chromatographic dimension by wavelet transforms. In a secondary step, the Multivariate Curve Resolution Alternating Least Squares (MCR-ALS) method is applied to previously compressed data sets obtained in the simultaneous analysis of multiple LC×LC-HRMS chromatographic runs from multiple samples...
June 23, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28643042/oct-in-alzheimer-s-disease-thinning-of-the-rnfl-and-superior-hemiretina
#14
João Paulo Cunha, Rita Proença, Arnaldo Dias-Santos, Rita Almeida, Helena Águas, Marta Alves, Ana Luísa Papoila, Carlota Louro, António Castanheira-Dinis
BACKGROUND: Peripapillary retinal nerve fiber layer (pRNFL) and internal macular layer thinning have been demonstrated in Alzheimer's disease (AD) with optical coherence tomography (OCT) studies. The purpose of this study is to compare the pRNFL thickness and overall retinal thickness (RT) in AD patients with non-AD patients, using spectral domain optical coherence tomography (SD-OCT) and determine the sectors most characteristically affected in AD. METHODS: A cross-sectional study was performed to determine the pRNFL and overall macular RT thicknesses in AD and non-AD patients, attending a tertiary hospital center...
June 22, 2017: Graefe's Archive for Clinical and Experimental Ophthalmology
https://www.readbyqxmd.com/read/28642341/use-of-intraoperative-local-field-potential-spectral-analysis-to-differentiate-basal-ganglia-structures-in-parkinson-s-disease-patients
#15
Rachel Kolb, Aviva Abosch, Gidon Felsen, John A Thompson
Identification of brain structures traversed during implantation of deep brain-stimulating (DBS) electrodes into the subthalamic nucleus (STN-DBS) for the treatment of Parkinson's disease (PD) frequently relies on subjective correspondence between kinesthetic response and multiunit activity. However, recent work suggests that local field potentials (LFP) could be used as a more robust signal to objectively differentiate subcortical structures. The goal of this study was to analyze the spectral properties of LFP collected during STN-DBS in order to objectively identify commonly traversed brain regions and improve our understanding of aberrant oscillations in the PD-related pathophysiological cortico-basal ganglia network...
June 2017: Physiological Reports
https://www.readbyqxmd.com/read/28642031/clustering-of-ms-2-spectra-using-unsupervised-methods-to-aid-the-identification-of-secondary-metabolites-from-pseudomonas-aeruginosa
#16
Tobias Depke, Raimo Franke, Mark Brönstrup
Pseudomonas aeruginosa is an important opportunistic pathogen that produces a large arsenal of small molecule virulence factors and quorum sensing signal molecules. The annotation of these secondary metabolites in untargeted, mass spectrometry-based metabolomics is difficult, as many of them cannot be found in common metabolite databases, and as manual annotation is tedious. We therefore developed an algorithm named CluMSID that uses cosine similarities of product ion spectra and neutral loss patterns in combination with unsupervised clustering methods such as multidimensional scaling, density based clustering and hierarchical clustering to group structurally similar compounds and hence facilitate their annotation...
June 4, 2017: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
https://www.readbyqxmd.com/read/28641528/drug-design-synthesis-and-in-vitro-evaluation-of-substituted-benzofurans-as-hsp90-inhibitors
#17
Sundeep Kadasi, Thadeu E M M Costa, Neha Arukala, Mallika Toshakani, Chaitanya Duggineti, Sreekanth Thota, Sayan Dutta Gupta, Shiva Raj, Carmen Penido, Maria G Henriques, Nulgumnalli Manjunathaiah Raghavendra
BACKGROUND: Heat shock protein 90 is a molecular chaperone required for the stability and function of several client proteins that promote cancer cell growth and/or survival. Discovery of Hsp90 inhibitors has emerged as an attractive target of research in cancer therapeutics. Natural products like geldanamycin and radicicol are established Hsp90 inhibitors, but face limitations with toxicity and inactivity, by in vivo studies respectively. However, they lay the logical starting point for the design of novel synthetic or semi-synthetic congeners as Hsp90 inhibitors...
June 22, 2017: Medicinal Chemistry
https://www.readbyqxmd.com/read/28641417/spectral-line-shapes-in-linear-absorption-and-two-dimensional-spectroscopy-with-skewed-frequency-distributions
#18
Marwa H Farag, Bernhard J Hoenders, Jasper Knoester, Thomas L C Jansen
The effect of Gaussian dynamics on the line shapes in linear absorption and two-dimensional correlation spectroscopy is well understood as the second-order cumulant expansion provides exact spectra. Gaussian solvent dynamics can be well analyzed using slope line analysis of two-dimensional correlation spectra as a function of the waiting time between pump and probe fields. Non-Gaussian effects are not as well understood, even though these effects are common in nature. The interpretation of the spectra, thus far, relies on complex case to case analysis...
June 21, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28641243/ecurves-a-temporal-shape-encoding
#19
Elena Bernardis, Yong Zhang, Ender Konukoglu, Yangming Ou, Harold Javitz, Leon Axel, Dimitris N Metaxas, Benoit Desjardins, Kilian M Pohl
OBJECTIVE: This paper presents a framework for temporal shape analysis to capture the shape and changes of anatomical structures from 3D+t(ime) medical scans. METHOD: We first encode the shape of a structure at each time point with the spectral signature, i.e., the eigenvalues and eigenfunctions of the Laplace operator. We then expand it to capture morphing shapes by tracking the eigenmodes across time according to the similarity of their eigenfunctions. The similarity metric is motivated by the fact that small shape deformations lead to minor changes in the eigenfunctions...
June 16, 2017: IEEE Transactions on Bio-medical Engineering
https://www.readbyqxmd.com/read/28641242/arrhythmia-mechanism-and-scaling-effect-on-the-spectral-properties-of-electroanatomical-maps-with-manifold-harmonics
#20
Margarita Sanroman-Junquera, Inmaculada Mora-Jimenez, Arcadi Garcia-Alberola, Antonio J Caamano, Beatriz Trenor, Jose Luis Rojo-Alvarez
Spatial and temporal processing of intracardiac electrograms provides relevant information to support the arrhythmia ablation during electrophysiological studies. Current Cardiac Navigation Systems (CNS) and Electrocardiographic Imaging (ECGI) build detailed three-dimensional electroanatomical maps (EAM), which represent the spatial anatomical distribution of bioelectrical features, such as activation time or voltage. We present a principled methodology for spectral analysis of both EAM geometry and bioelectrical feature in CNS or ECGI, including their spectral representation, cut-off frequency, or spatial sampling rate (SSR)...
June 15, 2017: IEEE Transactions on Bio-medical Engineering
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