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Spectral Analysis

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https://www.readbyqxmd.com/read/28221786/chemical-trends-in-solid-alkali-pertechnetates
#1
Jamie Weaver, Chuck Z Soderquist, Nancy M Washton, Andrew S Lipton, Paul L Gassman, Wayne W Lukens, Albert A Kruger, Nathalie A Wall, John S McCloy
Insight into the solid-state chemistry of pure technetium-99 ((99)Tc) oxides is required in the development of a robust immobilization and disposal system for nuclear waste stemming from the radiopharmaceutical industry, from the production of nuclear weapons, and from spent nuclear fuel. However, because of its radiotoxicity and the subsequent requirement of special facilities and handling procedures for research, only a few studies have been completed, many of which are over 20 years old. In this study, we report the synthesis of pure alkali pertechnetates (sodium, potassium, rubidium, and cesium) and analysis of these compounds by Raman spectroscopy, X-ray absorption spectroscopy (XANES and EXAFS), solid-state nuclear magnetic resonance (static and magic angle spinning), and neutron diffraction...
February 21, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28221329/relationship-between-anterior-lamina-cribrosa-surface-tilt-and-glaucoma-development-in-myopic-eyes
#2
Eun Jung Lee, Jong Chul Han, Changwon Kee
PURPOSE: To evaluate the anterior lamina cribrosa (LC) surface tilt angle in myopic eyes and associate it with glaucoma development. MATERIALS AND METHODS: In this retrospective study, medical records of myopic patients referred for glaucoma examination from July 1, 2012 to March 30, 2016 were reviewed. Comprehensive ophthalmic examination including spectral-domain optical coherence tomography were performed. We measured the angle of anterior LC surface tilt against Bruch's membrane opening from optical coherence tomography images at the center of the clinical optic disc margin...
February 17, 2017: Journal of Glaucoma
https://www.readbyqxmd.com/read/28221024/imet-a-network-based-computational-tool-to-assist-in-the-annotation-of-metabolites-from-tandem-mass-spectra
#3
Antoni Aguilar-Mogas, Marta Sales-Pardo, Miriam Navarro, Roger Guimerà, Oscar Yanes
Structural annotation of metabolites relies mainly on tandem mass spectrometry (MS/MS) analysis. However, approximately 90% of the known metabolites reported in metabolomic databases do not have annotated spectral data from standards. This situation has fostered the development of computational tools that predict fragmentation patterns in silico and compare these to experimental MS/MS spectra. However, because such methods require the molecular structure of the detected compound to be available for the algorithm, the identification of novel metabolites in organisms relevant for biotechnological and medical applications remains a challenge...
February 21, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28220590/biosynthesis-and-mass-spectral-fragmentation-pathways-of-13-c-and-15-n-labeled-cytochalasin-d-produced-by-xylaria-arbuscula
#4
Luciana da Silva Amaral, Taicia Pacheco Fill, Luiz Fernando Arruda Santos, Edson Rodrigues-Filho
The fungus Xylaria arbuscula was isolated as an endophyte from Cupressus lusitanica and has shown to be a prominent producer of cytochalasans, mainly cytochalasin C, D and Q. Cytochalasans comprise an important class of fungal secondary metabolites that have aroused attention due to their uncommon molecular structures and pronounced biological activities. Due to the few published studies on the ESI-MS/MS fragmentation of this important class of secondary metabolites, in the first part of our work we studied the cytochalasin D fragmentation pathways using an ESI-Q-ToF mass spectrometer coupled with liquid chromatography...
February 21, 2017: Journal of Mass Spectrometry: JMS
https://www.readbyqxmd.com/read/28220275/open-source-vendor-independent-automated-multi-beat-tissue-doppler-echocardiography-analysis
#5
Niti M Dhutia, Massoud Zolgharni, Michael Mielewczik, Madalina Negoita, Stefania Sacchi, Karikaran Manoharan, Darrel P Francis, Graham D Cole
Current guidelines for measuring cardiac function by tissue Doppler recommend using multiple beats, but this has a time cost for human operators. We present an open-source, vendor-independent, drag-and-drop software capable of automating the measurement process. A database of ~8000 tissue Doppler beats (48 patients) from the septal and lateral annuli were analyzed by three expert echocardiographers. We developed an intensity- and gradient-based automated algorithm to measure tissue Doppler velocities. We tested its performance against manual measurements from the expert human operators...
February 20, 2017: International Journal of Cardiovascular Imaging
https://www.readbyqxmd.com/read/28218950/a-robust-general-automatic-phase-correction-algorithm-for-high-resolution-nmr-data
#6
Vadim Zorin, Michael A Bernstein, Carlos Cobas
The trends towards rapid NMR data acquisition, automated NMR spectrum analysis, and data processing and analysis by more naïve users combine to place a higher burden on data processing software to automatically process these data. Downstream data analysis is compromised by poor processing, and the automated processing algorithms must therefore be robust and accurate. We describe a new algorithm for automatic phase correction of frequency-domain, high-resolution NMR spectra. We show this to be reliable for data derived from a wide variety of typical NMR usages...
February 20, 2017: Magnetic Resonance in Chemistry: MRC
https://www.readbyqxmd.com/read/28218302/nonlinear-infrared-spectroscopy-free-from-spectral-selection
#7
Anna Paterova, Shaun Lung, Dmitry A Kalashnikov, Leonid A Krivitsky
Infrared (IR) spectroscopy is an indispensable tool for many practical applications including material analysis and sensing. Existing IR spectroscopy techniques face challenges related to the inferior performance and the high cost of IR-grade components. Here, we develop a new method, which allows studying properties of materials in the IR range using only visible light optics and detectors. It is based on the nonlinear interference of entangled photons, generated via Spontaneous Parametric Down Conversion (SPDC)...
February 20, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28217242/investigating-state-restriction-in-fluorescent-protein-fret-using-time-resolved-fluorescence-and-anisotropy
#8
Thomas S Blacker, WeiYue Chen, Edward Avezov, Richard J Marsh, Michael R Duchen, Clemens F Kaminski, Angus J Bain
Most fluorescent proteins exhibit multiexponential fluorescence decays, indicating a heterogeneous excited state population. FRET between fluorescent proteins should therefore involve multiple energy transfer pathways. We recently demonstrated the FRET pathways between EGFP and mCherry (mC), upon the dimerization of 3-phosphoinositide dependent protein kinase 1 (PDK1), to be highly restricted. A mechanism for FRET restriction based on a highly unfavorable κ(2) orientation factor arising from differences in donor-acceptor transition dipole moment angles in a far from coplanar and near static interaction geometry was proposed...
January 26, 2017: Journal of Physical Chemistry. C, Nanomaterials and Interfaces
https://www.readbyqxmd.com/read/28217089/differential-modulation-of-rhythmic-brain-activity-in-healthy-adults-by-a-t-type-calcium-channel-blocker-an-meg-study
#9
Kerry D Walton, Emeline L Maillet, John Garcia, Timothy Cardozo, Isaac Galatzer-Levy, Rodolfo R Llinás
1-octanol is a therapeutic candidate for disorders involving the abnormal activation of the T-type calcium current since it blocks this current specifically. Such disorders include essential tremor and a group of neurological and psychiatric disorders resulting from thalamocortical dysrhythmia (TCD). For example, clinically, the observable phenotype in essential tremor is the tremor itself. The differential diagnostic of TCD is not based only on clinical signs and symptoms. Rather, TCD incorporates an electromagnetic biomarker, the presence of abnormal thalamocortical low frequency brain oscillations...
2017: Frontiers in Human Neuroscience
https://www.readbyqxmd.com/read/28216957/synthesis-of-some-novel-pyrazolo-3-4-d-pyrimidin-4-5h-one-derivatives-as-potential-antimicrobial-agent
#10
Dipen K Sureja, Sandip P Dholakia, Kantilal R Vadalia
OBJECTIVES: The aim of the present work was to synthesize a novel series of pyrazolo[3,4-d]pyrimidin-4(5H)-one derivatives and evaluate their in vitro antimicrobial activity. METHODS: Cyclization of an ortho-amino ester of 1-(2,4-dinitrophenyl)pyrazole with various aliphatic/aromatic nitriles under different reaction conditions such as conventional and microwave assisted synthesis, provided pyrazolo[3,4-d] pyrimidin-4(5H)-one derivatives. All the synthesized compounds were evaluated in vitro for their antimicrobial activity against selected bacteria and fungi by agar well diffusion method...
October 2016: Journal of Pharmacy & Bioallied Sciences
https://www.readbyqxmd.com/read/28216906/quality-by-design-multivariate-model-for-multicomponent-quantification-in-refining-process-of-honey
#11
Xiaoying Li, Zhisheng Wu, Xin Feng, Shanshan Liu, Xiaojie Yu, Qun Ma, Yanjiang Qiao
OBJECTIVE: A method for rapid analysis of the refining process of honey was developed based on near-infrared (NIR) spectroscopy. METHODS: Partial least square calibration models were built for the four components after the selection of the optimal spectral pretreatment method and latent factors. RESULTS: The models covered the samples of different temperatures and time points, therefore the models were robust and universal. CONCLUSIONS: These results highlighted that the NIR technology could extract the information of critical process and provide essential process knowledge of the honey refining process...
January 2017: Pharmacognosy Magazine
https://www.readbyqxmd.com/read/28216577/qm-hifsa-aided-structure-determination-of-succinilenes-a-d-new-triene-polyols-from-a-marine-derived-streptomyces-sp
#12
Munhyung Bae, So Hyun Park, Yun Kwon, Sang Kook Lee, Jongheon Shin, Joo-Won Nam, Dong-Chan Oh
Based on profiles of secondary metabolites produced by marine bacteria obtained using LC/MS, succinilenes A-D (1-4), new triene polyols, were discovered from a culture of a Streptomyces strain SAK1, which was collected in the southern area of Jeju Island, Republic of Korea. The gross structures of 1-4 were primarily determined through analysis of NMR spectra. The double bond geometries of the succinilenes, which could not be established from conventional ¹H NMR spectra because of the highly overlapped olefinic signals, were successfully deciphered using the recently developed quantum-mechanics-driven ¹H iterative full spin analysis (QM-HiFSA)...
February 14, 2017: Marine Drugs
https://www.readbyqxmd.com/read/28216342/near-infrared-monitoring-of-roller-compacted-ribbon-density-investigating-sources-of-variation-contributing-to-noisy-spectral-data
#13
Mary Ellen Crowley, Avril Hegarty, Michael A P McAuliffe, Graham E O'Mahony, Luke Kiernan, Kevin Hayes, Abina M Crean
The aim of this study was to highlight how variability in roller compacted ribbon quality can impact on NIR spectral measurement and to propose a simple method of data selection to remove erroneous spectra. The use of NIR spectroscopy for monitoring ribbon envelope density has been previously demonstrated, however to date there has been limited discussion as to how spectral data sets can contain erroneous outliers due to poor sample presentation to the NIR probes. In this study compacted ribbon of variable quality was produced from three separate blends of microcrystalline cellulose (MCC)/lactose/magnesium stearate at 8 Roll Force settings (2-16kN/cm)...
February 16, 2017: European Journal of Pharmaceutical Sciences
https://www.readbyqxmd.com/read/28216204/left-ventricular-assist-device-thrombosis-is-associated-with-an-increase-in-the-systolic-to-diastolic-velocity-ratio-measured-at-the-inflow-and-outflow-cannulae
#14
Ankit Jain, Ben Rohrer, Brian Gebhardt, Janis L Breeze, Joshua D Quick, Gregory Couper, Michael S Kiernan, Matthew Lawrence, Frederick C Cobey
OBJECTIVE: To determine whether the ratio of peak systolic-to-nadir diastolic velocity (S/D ratio) measured using Doppler at the left ventricular assist device (LVAD) inflow and outflow cannulae is associated with pump thrombosis and to determine whether there is an absolute decrease in the diastolic cannula velocities in LVAD thrombosis. DESIGN: Retrospective chart review. SETTING: University hospital. PARTICIPANTS: Patients who underwent LVAD exchange...
November 24, 2016: Journal of Cardiothoracic and Vascular Anesthesia
https://www.readbyqxmd.com/read/28215469/depression-and-implicit-emotion-processing-an-eeg-study
#15
Andrey V Bocharov, Gennady G Knyazev, Alexander N Savostyanov
OBJECTIVES: Depression is one of the most prevalent mental illnesses and is associated with changes in emotion processing. The aim of this study was to determine the influence of depressive symptoms on EEG oscillatory dynamics accompanying implicit processing of angry and happy facial expressions in 46 healthy subjects. METHODS: The Beck Depression Inventory was used to assess the presence of depressive symptoms in normal subjects. During the experiment, they were told to categorize the gender of angry, neutral, or happy faces presented to them, while high-resolution EEG was recorded...
February 16, 2017: Neurophysiologie Clinique, Clinical Neurophysiology
https://www.readbyqxmd.com/read/28215251/the-association-between-caffeine-consumption-and-objective-sleep-variables-is-dependent-on-adora2a-c-1083t-c-genotypes
#16
Rafael Almeida Nunes, Diego Robles Mazzotti, Camila Hirotsu, Monica L Andersen, Sergio Tufik, Lia Bittencourt
OBJECTIVE: To verify the association between c.1083T>C polymorphism in the adenosine receptor A2A gene (ADORA2A) and objective sleep, as well as the correlation between caffeine consumption, sleep parameters, and electroencephalographic spectral power in a large, population-based sample from São Paulo, Brazil. METHODS: This study was conducted in participants of the São Paulo Epidemiologic Sleep Study (EPISONO), a large, population-based survey consisting of a representative sample of the inhabitants of the city from São Paulo, Brazil, according to sex, age (20-80 years), and socioeconomic status in the year 2007...
February 2017: Sleep Medicine
https://www.readbyqxmd.com/read/28214755/identification-of-a-new-tert-leucinate-class-synthetic-cannabinoid-in-powder-and-spice-like-herbal-incenses-methyl-2-1-5-fluoropentyl-indole-3-carbonyl-amino-3-3-dimethyl-butanoate-5f-mdmb-pica
#17
Martijn D P Risseeuw, Peter Blanckaert, Vera Coopman, Stijn Van Quekelberghe, Serge Van Calenbergh, Jan Cordonnier
A brown powder and different product packages of "spice-like" herbal incenses were analyzed using a systematic identification approach based on liquid chromatography with diode array detector (HPLC-PDA) and gas chromatography mass spectrometry (GC-MS) with computer based library search against spectral libraries. However, the most predominant compound in the methanolic sample solutions could not be identified. In order to elucidate the chemical structure, a more extensive analysis of the material was initiated using liquid chromatography mass spectrometry (LC-MS), electrospray high resolution mass spectrometry (ESI-HRMS) and (1)H, (13)C and (19)F nuclear magnetic resonance spectroscopy (NMR), which allowed the identification and characterization of the major compound as methyl 2-[[1-(5-fluoropentyl)indole-3-carbonyl]amino]-3,3-dimethyl-butanoate (5F-MDMB-PICA)...
February 4, 2017: Forensic Science International
https://www.readbyqxmd.com/read/28214576/amplified-induced-neural-oscillatory-activity-predicts-musicians-benefits-in-categorical-speech-perception
#18
Gavin M Bidelman
Event-related brain potentials (ERPs) reveal musical experience refines neural encoding and confers stronger categorical perception (CP) and neural organization for speech sounds. In addition to evoked brain activity, the human EEG can be decomposed into induced (non-phase-locked) response whose various frequency bands reflect different mechanisms of perceptual-cognitive processing. Here, we aimed to clarify which spectral properties of these neural oscillations are most prone to music-related neuroplasticity and which are linked to behavioral benefits in the categorization of speech...
February 15, 2017: Neuroscience
https://www.readbyqxmd.com/read/28214102/vitreomacular-adhesion-and-the-risk-of-neovascular-age-related-macular-degeneration
#19
Emilia Maggio, Antonio Polito, Massimo Guerriero, Guido Prigione, Barbara Parolini, Grazia Pertile
PURPOSE: To assess the prevalence of vitreomacular adhesion (VMA) in consecutive naïve eyes diagnosed with exudative age-related macular degeneration (AMD) in comparison with eyes with nonexudative AMD and age-matched controls, and to evaluate prospectively the incidence of vitreomacular interface changes over time and their influence on choroidal neovascularization (CNV) development. DESIGN: Retrospective cross-sectional analysis and longitudinal cohort study conducted at Sacrocuore Hospital, Negrar, Verona, Italy...
February 14, 2017: Ophthalmology
https://www.readbyqxmd.com/read/28212311/detection-of-atmospheric-methyl-mercaptan-using-wavelength-modulation-spectroscopy-with-multicomponent-spectral-fitting
#20
Zhenhui Du, Jiaxin Wan, Jinyi Li, Gang Luo, Hong Gao, Yiwen Ma
Detection of methyl mercaptan (CH₃SH) is essential for environmental atmosphere assessment and exhaled-breath analysis. This paper presents a sensitive CH₃SH sensor based on wavelength modulation spectroscopy (WMS) with a mid-infrared distributed feedback interband cascade laser (DFB-ICL). Multicomponent spectral fitting was used not only to enhance the sensitivity of the sensor but also to determine the concentration of interferents (atmospheric water and methane). The results showed that the uncertainties in the measurement of CH₃SH, H₂O, and CH₄ were less than 1...
February 16, 2017: Sensors
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