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Spectral Analysis

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https://www.readbyqxmd.com/read/28445789/characterisation-of-pb-induced-changes-and-prediction-of-pb-exposure-in-microalgae-using-infrared-spectroscopy
#1
Ly Dao, John Beardall, Philip Heraud
Macromolecular changes in Chlorella sp. FleB1 and Scenedesmus acutus YaA6 exposed to Pb were characterised by Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) spectroscopy. Spectra were collected in the mid-infrared spectral region and a chemometric approach was used to analyse the spectra. Principal Component Analysis showed that under Pb treatment, carbohydrates and lipids increased while proteins and phosphorylated molecules decreased in both the isolates. These conclusions were corroborated by conventional measurements of photosynthesis and neutral lipids...
April 14, 2017: Aquatic Toxicology
https://www.readbyqxmd.com/read/28445065/neomacrophorin-x-a-4-4-3-propellane-type-meroterpenoid-from-trichoderma-sp-1212-03
#2
Kazuaki Kusakabe, Yuna Honmura, Shota Uesugi, Akio Tonouchi, Hayato Maeda, Ken-Ichi Kimura, Hiroyuki Koshino, Masaru Hashimoto
Neomacrophorin X (1) was isolated from Trichoderma sp. 1212-03. Heteronuclear multiple bond correlation (HMBC) spectral analysis indicated a unique [4.4.3]propellane framework, which was verified by the (1)H and (13)C chemical shift calculations based on density functional theory (DFT) and subsequent comparison with experimental data obtained in CDCl3. The DFT-based electronic circular dichroism (ECD) calculations were effective in not only determining the absolute configuration but also confirming the relative structure...
April 26, 2017: Journal of Natural Products
https://www.readbyqxmd.com/read/28444808/fast-and-simple-discriminative-analysis-of-anthocyanins-containing-berries-using-lc-ms-spectral-data
#3
Heejung Yang, Hyun Woo Kim, Yong Soo Kwon, Ho Kyong Kim, Sang Hyun Sung
INTRODUCTION: Anthocyanins are potent antioxidant agents that protect against many degenerative diseases; however, they are unstable because they are vulnerable to external stimuli including temperature, pH and light. This vulnerability hinders the quality control of anthocyanin-containing berries using classical high-performance liquid chromatography (HPLC) analytical methodologies based on UV or MS chromatograms. OBJECTIVE: To develop an alternative approach for the quality assessment and discrimination of anthocyanin-containing berries, we used MS spectral data acquired in a short analytical time rather than UV or MS chromatograms...
April 25, 2017: Phytochemical Analysis: PCA
https://www.readbyqxmd.com/read/28444788/night-sleep-in-patients-with-vegetative-state
#4
Yuri G Pavlov, Steffen Gais, Friedemann Müller, Monika Schönauer, Barbara Schäpers, Jan Born, Boris Kotchoubey
Polysomnographic recording of night sleep was carried out in 15 patients with the diagnosis vegetative state (syn. unresponsive wakefulness syndrome). Sleep scoring was performed by three raters, and confirmed by means of a spectral power analysis of the electroencephalogram, electrooculogram and electromyogram. All patients but one exhibited at least some signs of sleep. In particular, sleep stage N1 was found in 13 patients, N2 in 14 patients, N3 in nine patients, and rapid eye movement sleep in 10 patients...
April 26, 2017: Journal of Sleep Research
https://www.readbyqxmd.com/read/28442796/resonant-raman-scattering-based-approaches-for-the-quantitative-assessment-of-nanometric-znmgo-layers-in-high-efficiency-chalcogenide-solar-cells
#5
Maxim Guc, Dimitrios Hariskos, Lorenzo Calvo-Barrio, Philip Jackson, Florian Oliva, Paul Pistor, Alejandro Perez-Rodriguez, Victor Izquierdo-Roca
This work reports a detailed resonant Raman scattering analysis of ZnMgO solid solution nanometric layers that are being developed for high efficiency chalcogenide solar cells. This includes layers with thicknesses below 100 nm and compositions corresponding to Zn/(Zn + Mg) content rations in the range between 0% and 30%. The vibrational characterization of the layers grown with different compositions and thicknesses has allowed deepening in the knowledge of the sensitivity of the different Raman spectral features on the characteristics of the layers, corroborating the viability of resonant Raman scattering based techniques for their non-destructive quantitative assessment...
April 25, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28442640/left-recumbent-position-decreases-heart-rate-without-alterations-in-cardiac-autonomic-nervous-system-activity-in-healthy-young-adults
#6
Konosuke Sasaki, Mayu Haga, Yoichi Endo, Junko Fujiwara, Ryoko Maruyama
Some studies have reported that recumbent position may have advantages in patients with heart disease and in pregnancy. However, it remains controversial whether recumbent position affects autonomic nervous system activity and hemodynamics in healthy adults. The aim of this study was to evaluate alterations in heart rate variability (HRV) and hemodynamics in the supine, left recumbent and right recumbent positions in healthy young adults. A total of 80 participants aged 22.8 ± 3.1 years were enrolled in this observational study...
2017: Tohoku Journal of Experimental Medicine
https://www.readbyqxmd.com/read/28442333/effects-of-auditory-stimuli-on-electrical-activity-in-the-brain-during-cycle-ergometry
#7
Marcelo Bigliassi, Costas I Karageorghis, Michael J Wright, Guido Orgs, Alexander V Nowicky
The present study sought to further understanding of the brain mechanisms that underlie the effects of music on perceptual, affective, and visceral responses during whole-body modes of exercise. Eighteen participants were administered light-to-moderate intensity bouts of cycle ergometer exercise. Each exercise bout was of 12-min duration (warm-up [3min], exercise [6min], and warm-down [3min]). Portable techniques were used to monitor the electrical activity in the brain, heart, and muscle during the administration of three conditions: music, audiobook, and control...
April 22, 2017: Physiology & Behavior
https://www.readbyqxmd.com/read/28442276/investigating-the-effects-of-nitrous-oxide-sedation-on-frontal-parietal-interactions
#8
Ryu Ji-Ho, Pil-Jong Kim, Hong-Gee Kim, Yong-Seo Koo, Teo Jeon Shin
Although functional connectivity has received considerable attention in the study of consciousness, few studies have investigated functional connectivity limited to the sedated state where consciousness is maintained but impaired. The aim of the present study was to investigate changes in functional connectivity of the parietal-frontal network resulting from nitrous oxide-induced sedation, and to determine the neural correlates of cognitive impairment during consciousness transition states. Electroencephalography was acquired from healthy adult patients who underwent nitrous oxide inhalation to induce cognitive impairment, and was analyzed using Granger causality (GC)...
April 22, 2017: Neuroscience Letters
https://www.readbyqxmd.com/read/28441930/ribosomal-subunit-protein-typing-using-matrix-assisted-laser-desorption-ionization-time-of-flight-mass-spectrometry-maldi-tof-ms-for-the-identification-and-discrimination-of-aspergillus-species
#9
Sayaka Nakamura, Hiroaki Sato, Reiko Tanaka, Yoko Kusuya, Hiroki Takahashi, Takashi Yaguchi
BACKGROUND: Accurate identification of Aspergillus species is a very important subject. Mass spectral fingerprinting using matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) is generally employed for the rapid identification of fungal isolates. However, the results are based on simple mass spectral pattern-matching, with no peak assignment and no taxonomic input. We propose here a ribosomal subunit protein (RSP) typing technique using MALDI-TOF MS for the identification and discrimination of Aspergillus species...
April 26, 2017: BMC Microbiology
https://www.readbyqxmd.com/read/28441570/neural-indices-of-phonemic-discrimination-and-sentence-level-speech-intelligibility-in-quiet-and-noise-a-p3-study
#10
Tess K Koerner, Yang Zhang, Peggy B Nelson, Boxiang Wang, Hui Zou
This study examined how speech babble noise differentially affected the auditory P3 responses and the associated neural oscillatory activities for consonant and vowel discrimination in relation to segmental- and sentence-level speech perception in noise. The data were collected from 16 normal-hearing participants in a double-oddball paradigm that contained a consonant (/ba/ to /da/) and vowel (/ba/ to /bu/) change in quiet and noise (speech-babble background at a -3 dB signal-to-noise ratio) conditions. Time-frequency analysis was applied to obtain inter-trial phase coherence (ITPC) and event-related spectral perturbation (ERSP) measures in delta, theta, and alpha frequency bands for the P3 response...
April 18, 2017: Hearing Research
https://www.readbyqxmd.com/read/28440351/characterization-of-benign-thyroid-nodules-with-hyperspace-hyper-spectral-analysis-for-characterization-in-echography-before-and-after-percutaneous-laser-ablation-a-pilot-study
#11
Simona Granchi, Enrico Vannacci, Elena Biagi
AIMS: To evaluate the capability of the HyperSPACE (Hyper SPectral Analysis for Characterization in Echography) method in tissue characterization, in order to provide information for the laser treatment of benign thyroid nodules in respect of conventional B-mode images and elastography. MATERIAL AND METHODS: The method, based on the spectral analysis of the raw radiofrequency ultrasonic signal, was applied to characterize the nodule before and after laser treatment...
April 22, 2017: Medical Ultrasonography
https://www.readbyqxmd.com/read/28439768/discrimination-of-wine-lactic-acid-bacteria-by-raman-spectroscopy
#12
Susan B Rodriguez, Mark A Thornton, Roy J Thornton
Species of Lactobacillus, Pediococcus, Oenococcus, and Leuconostoc play an important role in winemaking, as either inoculants or contaminants. The metabolic products of these lactic acid bacteria have considerable effects on the flavor, aroma, and texture of a wine. However, analysis of a wine's microflora, especially the bacteria, is rarely done unless spoilage becomes evident, and identification at the species or strain level is uncommon as the methods required are technically difficult and expensive. In this work, we used Raman spectral fingerprints to discriminate 19 strains of Lactobacillus, Pediococcus, and Oenococcus...
April 24, 2017: Journal of Industrial Microbiology & Biotechnology
https://www.readbyqxmd.com/read/28439729/macular-morphology-in-former-preterm-and-full-term-infants-aged-4-to-10%C3%A2-years
#13
Achim Fieß, Johannes Janz, Alexander K Schuster, Ruth Kölb-Keerl, Markus Knuf, Bernd Kirchhof, Philipp S Muether, Jacqueline Bauer
OBJECTIVE: To analyse macular retinal and choroidal layer thickness in former preterm and full-term infants and to assess associated perinatal influence factors and functional correlation. METHODS: This prospective controlled, cross-sectional, hospital-based study in a tertiary center of maximum care examined former preterm infants with a gestational age (GA) ≤ 32 weeks and full-term neonates currently aged 4 to 10 years. We investigated data from 397 infants, analysing total foveal retinal thickness and six distinct macular retinal layer and choroidal layer measurements via spectral-domain optical coherence tomography...
April 25, 2017: Graefe's Archive for Clinical and Experimental Ophthalmology
https://www.readbyqxmd.com/read/28439620/development-of-an-optimal-filter-substrate-for-the-identification-of-small-microplastic-particles-in-food-by-micro-raman-spectroscopy
#14
Barbara E Oßmann, George Sarau, Sebastian W Schmitt, Heinrich Holtmannspötter, Silke H Christiansen, Wilhelm Dicke
When analysing microplastics in food, due to toxicological reasons it is important to achieve clear identification of particles down to a size of at least 1 μm. One reliable, optical analytical technique allowing this is micro-Raman spectroscopy. After isolation of particles via filtration, analysis is typically performed directly on the filter surface. In order to obtain high qualitative Raman spectra, the material of the membrane filters should not show any interference in terms of background and Raman signals during spectrum acquisition...
April 24, 2017: Analytical and Bioanalytical Chemistry
https://www.readbyqxmd.com/read/28439325/graph-frequency-analysis-of-brain-signals
#15
Weiyu Huang, Leah Goldsberry, Nicholas F Wymbs, Scott T Grafton, Danielle S Bassett, Alejandro Ribeiro
This paper presents methods to analyze functional brain networks and signals from graph spectral perspectives. The notion of frequency and filters traditionally defined for signals supported on regular domains such as discrete time and image grids has been recently generalized to irregular graph domains, and defines brain graph frequencies associated with different levels of spatial smoothness across the brain regions. Brain network frequency also enables the decomposition of brain signals into pieces corresponding to smooth or rapid variations...
October 2016: IEEE Journal of Selected Topics in Signal Processing
https://www.readbyqxmd.com/read/28438369/independent-prognostic-importance-of-respiratory-instability-and-sympathetic-nerve-activity-in-patients-with-chronic-heart-failure
#16
Hidetsugu Asanoi, Daisuke Harada, Yoshitaka Oda, Hiroshi Ueno, Junya Takagawa, Hisanari Ishise, Yukiko Goso, Shuji Joho, Hiroshi Inoue
BACKGROUND: Respiratory instability in chronic heart failure (CHF) is characterized by irregularly rapid respiration or non-periodic breathing rather than by Cheyne-Stokes respiration. We developed a new quantitative measure of respiratory instability (RSI) and examined its independent prognostic impact upon CHF. METHODS: In 87 patients with stable CHF, respiratory flow and muscle sympathetic nerve activity (MSNA) were simultaneously recorded. RSI was calculated from the frequency distribution of respiratory spectral components and very low frequency components...
April 21, 2017: Journal of Cardiology
https://www.readbyqxmd.com/read/28438009/modulation-format-free-and-automatic-bias-control-for-optical-iq-modulators-based-on-dither-correlation-detection
#17
Xiaolei Li, Lei Deng, Xiaoman Chen, Mengfan Cheng, Songnian Fu, Ming Tang, Deming Liu
A novel automatic bias control (ABC) method for optical in-phase and quadrature (IQ) modulator is proposed and experimentally demonstrated. In the proposed method, two different low frequency sine wave dither signals are generated and added on to the I/Q bias signal respectively. Instead of power monitoring of the harmonics of the dither signal, dither-correlation detection is proposed and used to adjust the bias voltages of the optical IQ modulator. By this way, not only frequency spectral analysis isn't required but also the directional bias adjustment could be realized, resulting in the decrease of algorithm complexity and the growth of convergence rate of ABC algorithm...
April 17, 2017: Optics Express
https://www.readbyqxmd.com/read/28437899/adaptively-loaded-im-dd-optical-ofdm-based-on-set-partitioned-qam-formats
#18
Jian Zhao, Lian-Kuan Chen
We investigate the constellation design and symbol error rate (SER) of set-partitioned (SP) quadrature amplitude modulation (QAM) formats. Based on the SER analysis, we derive the adaptive bit and power loading algorithm for SP QAM based intensity-modulation direct-detection (IM/DD) orthogonal frequency division multiplexing (OFDM). We experimentally show that the proposed system significantly outperforms the conventional adaptively-loaded IM/DD OFDM and can increase the data rate from 36 Gbit/s to 42 Gbit/s in the presence of severe dispersion-induced spectral nulls after 40-km single-mode fiber...
April 17, 2017: Optics Express
https://www.readbyqxmd.com/read/28437584/high-field-95-mo-and-183-w-static-and-mas-nmr-study-of-polyoxometalates
#19
Mohamed Haouas, Julien Trébosc, Catherine Roch-Marchal, Emmanuel Cadot, Francis Taulelle, Charlotte Martineau-Corcos
The potential of high-field NMR to measure solid-state (95) Mo and (183) W NMR in polyoxometalates (POMs) is explored using some archetypical structures like Lindqvist, Keggin, and Dawson as model compounds that are well characterized in solution. NMR spectra in static and under magic angle spinning (MAS) were obtained, and their analysis allowed extraction of the NMR parameters, including chemical shift anisotropy (CSA) and quadrupolar coupling parameters. Despite the inherent difficulties of measurement in solid state of these low-gamma NMR nuclei, due mainly to the low spectral resolution and poor signal-to-noise ratio, the observed global trends compare well with the solution state NMR data...
April 24, 2017: Magnetic Resonance in Chemistry: MRC
https://www.readbyqxmd.com/read/28437483/quantitative-microvascular-analysis-of-retinal-venous-occlusions-by-spectral-domain-optical-coherence-tomography-angiography
#20
Nicole Koulisis, Alice Y Kim, Zhongdi Chu, Anoush Shahidzadeh, Bruce Burkemper, Lisa C Olmos de Koo, Andrew A Moshfeghi, Hossein Ameri, Carmen A Puliafito, Veronica L Isozaki, Ruikang K Wang, Amir H Kashani
PURPOSE: To quantitatively evaluate the retinal microvasculature in human subjects with retinal venous occlusions (RVO) using optical coherence tomography angiography (OCTA). DESIGN: Retrospective, cross-sectional, observational case series. PARTICIPANTS: Sixty subjects (84 eyes) were included (20 BRVO, 14 CRVO, 24 unaffected fellow eyes, and 26 controls). METHODS: OCTA was performed on a prototype, spectral domain-OCTA system in the 3x3mm central macular region...
2017: PloS One
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