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Spectral Analysis

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https://www.readbyqxmd.com/read/28933972/visual-acuity-and-macular-and-peripapillary-thickness-in-high-myopia
#1
Solmaz Abdolrahimzadeh, Francesco Parisi, Andrea Maria Plateroti, Federica Evangelista, Vito Fenicia, Gianluca Scuderi, Santi Maria Recupero
PURPOSE: To investigate best corrected visual acuity (BCVA), and choroidal and retinal thickness values between high myopes without myopic maculopathy and emmetropes. MATERIALS AND METHODS: Case control study where 53 myopes with axial length (AL) above 26 mm without myopic maculopathy and 53 age-matched emmetropes with AL between 21.50 and 24.50 were included as controls. Complete ophthalmological examination and biometry were performed. Choroidal and individual retinal layer thickness maps using spectral domain optical coherence tomography were obtained in the macular and peripapillary area with enhanced depth imaging...
September 21, 2017: Current Eye Research
https://www.readbyqxmd.com/read/28933158/first-principles-fe-l2-3-edge-and-o-k-edge-xanes-and-xmcd-spectra-for-iron-oxides
#2
Michel Sassi, Carolyn I Pearce, Paul S Bagus, Elke Arenholz, Kevin M Rosso
X-ray absorption near edge structure (XANES) and X-ray magnetic circular dichroism (XMCD) spectroscopies are tools in widespread use for providing detailed local atomic structure, oxidation state, and magnetic structure information for materials and organometallic complexes. Analysis of these spectra for transition metal L-edges is routinely performed on the basis of ligand-field multiplet theory because one- and two-particle mean field ab initio methods typically cannot describe the multiplet structure. Here we show that multireference configuration interaction (MRCI) calculations can satisfactorily reproduce measured XANES spectra for a range of complex iron oxide materials including hematite and magnetite...
September 21, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/28933070/variations-in-the-endogenous-fluorescence-of-rabbit-corneas-after-mechanical-property-alterations
#3
Antonio Ortega-Martinez, Genna Touchette, Hong Zhu, Irene E Kochevar, Walfre Franco
Keratoconus is an eye disease in which the cornea progressively deforms due to loss of cornea mechanical rigidity, and thus causes deterioration of visual acuity. Techniques to characterize the mechanical characteristics of the cornea are important to better monitor changes and response to treatments. To investigate the feasibility of using the endogenous fluorescence of cornea for monitoring alterations of its mechanical rigidity, linear tensiometry was used to quantitate stiffness and Young's modulus (YM) after treatments that increase cornea stiffness (collagen photocross-linking) or decrease stiffness (enzymatic digestion)...
September 2017: Journal of Biomedical Optics
https://www.readbyqxmd.com/read/28932775/spectral-and-raw-quasi-in-situ-energy-dispersive-x-ray-data-captured-via-a-tem-analysis-of-an-ods-austenitic-stainless-steel-sample-under-1%C3%A2-mev-kr-2-high-temperature-irradiation
#4
Adam J Brooks, Zhongwen Yao
The data presented in this article is related to the research experiment, titled: 'Quasi in-situ energy dispersive X-ray spectroscopy observation of matrix and solute interactions on Y-Ti-O oxide particles in an austenitic stainless steel under 1 MeV Kr(2+) high temperature irradiation' (Brooks et al., 2017) [1]. Quasi in-situ analysis during 1 MeV Kr(2+) 520 °C irradiation allowed the same microstructural area to be observed using a transmission electron microscope (TEM), on an oxide dispersion strengthened (ODS) austenitic stainless steel sample...
October 2017: Data in Brief
https://www.readbyqxmd.com/read/28932243/sensitive-wavelengths-selection-in-identification-of-ophiopogon-japonicus-based-on-near-infrared-hyperspectral-imaging-technology
#5
Zhengyan Xia, Chu Zhang, Haiyong Weng, Pengcheng Nie, Yong He
Hyperspectral imaging (HSI) technology has increasingly been applied as an analytical tool in fields of agricultural, food, and Traditional Chinese Medicine over the past few years. The HSI spectrum of a sample is typically achieved by a spectroradiometer at hundreds of wavelengths. In recent years, considerable effort has been made towards identifying wavelengths (variables) that contribute useful information. Wavelengths selection is a critical step in data analysis for Raman, NIRS, or HSI spectroscopy. In this study, the performances of 10 different wavelength selection methods for the discrimination of Ophiopogon japonicus of different origin were compared...
2017: International Journal of Analytical Chemistry
https://www.readbyqxmd.com/read/28930882/reproducibility-of-bruch-s-membrane-opening-minimum-rim-width-measurements-with-spectral-domain-optical-coherence-tomography
#6
Keunheung Park, Jinmi Kim, Jiwoong Lee
PURPOSE: To evaluate the reproducibility of Bruch's membrane opening-minimum rim width (BMO-MRW) measurements obtained with Spectralis optical coherence tomography (OCT) in normal and glaucoma subjects. METHODS: In total, 123 eyes from 123 subjects (65 healthy, 58 glaucoma subjects) were included. BMO-MRW measurements were repeated three times during the same visit using Spectralis OCT. The BMO points and internal limiting membrane were identified with automated software and corrected manually when necessary...
September 19, 2017: Journal of Glaucoma
https://www.readbyqxmd.com/read/28930543/eeg-and-erp-biomarkers-of-alzheimer-s-disease-a-critical-review
#7
Andras Horvath, Anna Szucs, Gabor Csukly, Anna Sakovics, Gabor Stefanics, Anita Kamondi
Here we critically review studies that used electroencephalography (EEG) or event-related potential (ERP) indices as a biomarker of Alzheimer's disease. In the first part we overview studies that relied on visual inspection of EEG traces and spectral characteristics of EEG. Second, we survey analysis methods motivated by dynamical systems theory (DST) as well as more recent network connectivity approaches. In the third part we review studies of sleep.  Next, we compare the utility of early and late ERP components in dementia research...
January 1, 2018: Frontiers in Bioscience (Landmark Edition)
https://www.readbyqxmd.com/read/28930139/critical-analysis-on-characterization-systemic-effect-and-therapeutic-potential-of-beta-sitosterol-a-plant-derived-orphan-phytosterol
#8
REVIEW
Muhammad Shahdaat Bin Sayeed, Selim Muhammad Rezaul Karim, Tasnuva Sharmin, Mohammed Monzur Morshed
Beta-sitosterol (BS) is a phytosterol, widely distributed throughout the plant kingdom and known to be involved in the stabilization of cell membranes. To compile the sources, physical and chemical properties, spectral and chromatographic analytical methods, synthesis, systemic effects, pharmacokinetics, therapeutic potentials, toxicity, drug delivery and finally, to suggest future research with BS, classical as well as on-line literature were studied. Classical literature includes classical books on ethnomedicine and phytochemistry, and the electronic search included Pubmed, SciFinder, Scopus, the Web of Science, Google Scholar, and others...
November 15, 2016: Medicines (Basel, Switzerland)
https://www.readbyqxmd.com/read/28929262/status-source-identification-and-health-risks-of-potentially-toxic-element-concentrations-in-road-dust-in-a-medium-sized-city-in-a-developing-country
#9
S M Praveena, A Z Aris
This study aims to determine the status of potentially toxic element concentrations of road dust in a medium-sized city (Rawang, Malaysia). This study adopts source identification via enrichment factor, Pearson correlation analysis, and Fourier spectral analysis to identify sources of potentially toxic element concentrations in road dust in Rawang City, Malaysia. Health risk assessment was conducted to determine potential health risks (carcinogenic and non-carcinogenic risks) among adults and children via multiple pathways (i...
September 19, 2017: Environmental Geochemistry and Health
https://www.readbyqxmd.com/read/28928507/characteristics-of-xanthosoma-sagittifolium-roots-during-cooking-using-physicochemical-analysis-uniaxial-compression-multispectral-imaging-and-low-field-nmr-spectroscopy
#10
Abena Achiaa Boakye, María Gudjónsdóttir, Jacob Lercke Skytte, Ioannis S Chronakis, Faustina Dufie Wireko-Manu, Ibok Oduro
To effectively promote the industrial utilization of cocoyam (Xanthosoma sagittifolium) roots for enhanced food sustainability and security, there is a need to study their molecular, mechanical and physicochemical properties in detail. The physicochemical and textural characteristics of the red and white varieties of cocoyam roots were thus analysed by low field nuclear magnetic resonance relaxometry, multispectral imaging, uniaxial compression testing, and relevant physicochemical analysis in the current study...
August 2017: Journal of Food Science and Technology
https://www.readbyqxmd.com/read/28928372/aln-gan-digital-alloy-for-mid-and-deep-ultraviolet-optoelectronics
#11
Wei Sun, Chee-Keong Tan, Nelson Tansu
The AlN/GaN digital alloy (DA) is a superlattice-like nanostructure formed by stacking ultra-thin ( ≤ 4 monolayers) AlN barriers and GaN wells periodically. Here we performed a comprehensive study on the electronics and optoelectronics properties of the AlN/GaN DA for mid- and deep-ultraviolet (UV) applications. Our numerical analysis indicates significant miniband engineering in the AlN/GaN DA by tuning the thicknesses of AlN barriers and GaN wells, so that the effective energy gap can be engineered from ~3...
September 19, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28926685/nir-absorbing-metal-free-organic-porphyrin-and-phthalocyanine-dyes-for-panchromatic-dscs
#12
Phillip Brogdon, Hammad Cheema, Jared Heath Delcamp
Dye-sensitized solar cells (DSCs) are a promising source of renewable energy. However, power conversion efficiency (PCE) of devices has been limited largely by the difficulty of producing electricity using photons from the near-infrared (NIR) spectral region. Metal-free organic sensitizers frequently employ strong electron donating or withdrawing moieties to tune the optical band gap to allow the absorption of lower energy wavelengths in charge transfer systems while porphyrins and phthalocyanines use substituents to shift the Soret and Q bands toward lower energy absorption...
September 19, 2017: ChemSusChem
https://www.readbyqxmd.com/read/28926370/photon-counting-computed-tomography-for-vascular-imaging-of-the-head-and-neck-first-in-vivo-human-results
#13
Rolf Symons, Daniel S Reich, Mohammadhadi Bagheri, Tyler E Cork, Bernhard Krauss, Stefan Ulzheimer, Steffen Kappler, David A Bluemke, Amir Pourmorteza
PURPOSE: The purpose of this study was to evaluate image quality of a spectral photon-counting detector (PCD) computed tomography (CT) system for evaluation of major arteries of the head and neck compared with conventional single-energy CT scans using energy-integrating detectors (EIDs). METHODS: In this institutional review board-approved study, 16 asymptomatic subjects (7 men) provided informed consent and received both PCD and EID contrast-enhanced CT scans of the head and neck (mean age, 58 years; range, 46-75 years)...
September 18, 2017: Investigative Radiology
https://www.readbyqxmd.com/read/28926210/clinical-relevance-of-retinal-structure-in-children-with-laser-treated-retinopathy-of-prematurity-versus-controls-using-optical-coherence-tomography
#14
Florina Stoica, Adela Chirita-Emandi, Nicoleta Andreescu, Alina Stanciu, Cristian G Zimbru, Maria Puiu
PURPOSE: We aimed to assess the macular anatomy using spectral domain optical coherence tomography (SD-OCT), in children born preterm who had laser-treated retinopathy of prematurity (ROP), and to investigate the relationship between structural changes in macula and visual function. METHODS: Thirty-seven 3-8 years old children were included in the study in two groups: 20 children born preterm [(<34 weeks of gestation, birthweight (BW) <2000 g)] who had laser-treated ROP in the Neonatology Department, Municipal Clinical Emergency Hospital of Timisoara, Romania; and 17 controls (children born at term, without eye disease, matched for age and gender)...
September 19, 2017: Acta Ophthalmologica
https://www.readbyqxmd.com/read/28926203/qualitative-and-quantitative-analysis-of-chemical-constituents-in-ardisiae-japonicae-herba
#15
Ke-Yun Yu, Wen Gao, Shang-Zhen Li, Wei Wu, Pei Li, Li-Li Dou, Yuan-Zhong Wang, E-Hu Liu
Ardisiae Japonicae Herba is a well-known traditional Chinese medicine for the treatment of bronchitis conjunctivitis, pneumonia and trauma. In this work, a high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry method was firstly established for the separation and structural identification of the chemical constituents in Ardisiae Japonicae Herba. A total of 15 compounds including coumarins, flavonoid glycosides, and catechins were identified or tentatively characterized based on their chromatographic behaviors and mass spectral fragmentation and by comparisons with the reference standards...
September 19, 2017: Journal of Separation Science
https://www.readbyqxmd.com/read/28925800/investigation-of-attention-deficit-hyperactivity-disorder-adhd-sub-types-in-children-via-eeg-frequency-domain-analysis
#16
Ramazan Aldemir, Esra Demirci, Huseyin Per, Mehmet Canpolat, Sevgi Özmen, Mahmut Tokmakçı
This study aims to investigate the frequency domain effects and changes in Electroencephalographic (EEG) signals in children aged 7-12 years old who were diagnosed with Attention Deficit and Hyperactivity Disorder (ADHD) and which labelled subtypes of ADHD.The study's sample consisted of 20 healthy children and 20 ADHD children as control group. Of the 20 participants who were diagnosed with ADHD, 10 were classified as ADHD-I (inattentive subtype ADHD) and the other 10 were classified as ADHD-C (combined subtype ADHD)...
September 19, 2017: International Journal of Neuroscience
https://www.readbyqxmd.com/read/28925735/four-novel-bisabolane-type-sesquiterpenes-from-curcuma-longa
#17
Jing Wen, Tian-Yi Qiu, Xin-Jia Yan, Feng Qiu
Four novel bisabolane sesquiterpenes, turmerone A (1), turmerone B (2), turmerone C (3), and turmerone D (4), were isolated from the rhizomes of Curcuma longa. Their structures were elucidated on the basis of chemical and spectral analysis, including 1D, 2D NMR analyses and HRESIMS.
September 19, 2017: Journal of Asian Natural Products Research
https://www.readbyqxmd.com/read/28925698/an-ultraviolet-resonance-raman-spectroscopic-study-of-cisplatin-and-transplatin-interactions-with-genomic-dna
#18
Jiafeng Geng, Mena Aioub, Mostafa A El-Sayed, Bridgette A Barry
Ultraviolet resonance Raman (UVRR) spectroscopy is a label-free method to define biomacromolecular interactions with anticancer compounds. Using UVRR, we describe the binding interactions of two Pt(II) compounds, cisplatin (cis-diamminedichloroplatinum(II)) and its isomer, transplatin, with nucleotides and genomic DNA. Cisplatin binds to DNA and other cellular components and triggers apoptosis, whereas transplatin is clinically ineffective. Here, a 244 nm UVRR study shows that purine UVRR bands are altered in frequency and intensity when mononucleotides are treated with cisplatin...
September 19, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28925253/novel-trimodal-maldi-imaging-mass-spectrometry-ims3-at-10-%C3%AE-m-reveals-spatial-lipid-and-peptide-correlates-implicated-in-a%C3%AE-plaque-pathology-in-alzheimer-s-disease
#19
Ibrahim Kaya, Dimitri Brinet, Wojciech Michno, Mehmet Baskurt, Henrik Zetterberg, Kaj Blennow, Jörg Hanrieder
Multimodal chemical imaging using matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) can provide comprehensive molecular information in situ within the same tissue sections. This is of relevance for studying different brain pathologies such as Alzheimer's Disease (AD), where recent data suggest a critical relevance of co-localizing Aβ peptides and neuronal lipids. We here developed a novel trimodal, high-resolution (10µm) MALDI imaging MS (IMS) paradigm for negative- and positive ion mode lipid analysis and subsequent protein ion imaging on the same tissue section...
September 19, 2017: ACS Chemical Neuroscience
https://www.readbyqxmd.com/read/28925144/-induction-and-analysis-for-nir-features-of-frequently-used-mineral-traditional-chinese-medicines
#20
Long Chen, Ming-Yang Yuan, Ke-Li Chen
In order to provide theoretical basis for the rapid identification of mineral traditional Chinese medicines(TCM) with near infrared (NIR)diffuse reflectance spectroscopy, Characteristic NIR spectra of 51 kinds of mineral TCMs were generalized and compared on the basis of the previous research, and the characteristic spectral bands were determined and analyzed by referring to mineralogical and geological literatures. It turned out that the NIR features of mineral TCMs were mainly at 8 000-4 000 cm ⁻¹ wavebands, which can be assigned as the absorption of water, -OH and[CO3 ²⁻] and so on...
October 2016: Zhongguo Zhong Yao za Zhi, Zhongguo Zhongyao Zazhi, China Journal of Chinese Materia Medica
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