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https://www.readbyqxmd.com/read/28239717/simulations-and-spectra-of-water-in-co-matrices
#1
Rafael Escribano, Emilio Artacho, Akira Kouchi, Tetusya Hama, Yuki Kimura, Hiroshi Hidaka, Naoki Watanabe
Models for the inclusion of water molecules in carbon monoxide matrices are developed using density functional theory applied to amorphous solid systems. The models cover a large range of systems for smaller or larger CO matrices with different water content, consisting of either individual H2O molecules or small clusters linked by H-bonds. The vibrational spectra of the samples are predicted at the minimum of their potential energy surface. The spectra allow instances where the water molecules remain isolated or form aggregates to be discerned, and they also provide an indication of the strength of the H-bonding, when present...
February 27, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28239715/clustering-in-vibrated-monolayers-of-granular-rods
#2
M González-Pinto, F Borondo, Y Martínez-Ratón, E Velasco
We investigate the ordering properties of vertically-vibrated monolayers of granular cylinders in a circular container at high packing fraction. In line with previous works by other groups, we identify liquid-crystalline ordering behaviour similar to that of two-dimensional hard rectangular particles subject to thermal equilibrium fluctuations. However, due to dissipation, there is a much stronger tendency for particles to cluster into parallel arrangements in the granular system. These clusters behave as a polydisperse mixture of long life-time 'superparticles', and some aspects of the system behaviour can be understood by applying mean-field theories for equilibrium hard rectangles, based on two-body correlations, to these 'superparticles'...
February 27, 2017: Soft Matter
https://www.readbyqxmd.com/read/28239699/stabilization-of-carbocations-ch3-c2h5-i-c3h7-tert-bu-and-cyclo-pentyl-in-solid-phases-experimental-data-versus-calculations
#3
Evgenii S Stoyanov, Anton S Nizovtsev
Comparison of experimental infrared (IR) spectra of the simplest carbocations (with the weakest carborane counterions in terms of basicity, CHB11Hal11(-), Hal = F, Cl) with their calculated IR spectra revealed that they are completely inconsistent, as previously reported for the t-Bu(+) cation [Stoyanov E. S., et al. J. Phys. Chem. A, 2015, 119, 8619]. This means that the generally accepted explanation of hyperconjugative stabilization of the carbocations should be revised. According to the theory, one CH bond (denoted as ) from each CH3/CH2 group transfers its σ-electron density to the empty 2pz orbital of the sp(2) C atom, whereas the σ-electron density on the other CH bonds of the CH3/CH2 group slightly increases...
February 27, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28237901/detection-of-bisphenol-a-using-palm-size-nanoaptamer-analyzer
#4
Hyun Jeong Lim, Beelee Chua, Ahjeong Son
We have demonstrated a palm-size NanoAptamer analyzer capable of detecting bisphenol A (BPA) at environmentally relevant concentrations (<1ng/mL or ppb). It is designed for performing reaction and fluorescence measurement on single cuvette sample. Modified NanoGene assay was used as the sensing mechanism where signaling DNA and QD655 was tethered to QD565 and magnetic bead via the aptamer. Aptamer affinity with BPA resulted in the release of the signaling DNA and QD655 from the complex and hence corresponding decrease in QD655 fluorescence measurement signal...
February 21, 2017: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/28237824/damage-detection-of-fatigue-cracks-under-nonlinear-boundary-condition-using-subharmonic-resonance
#5
Mengyang Zhang, Li Xiao, Wenzhong Qu, Ye Lu
In recent years, the nonlinear ultrasonic technique has been widely utilized for detecting fatigue crack, one of the most common forms of damage. However, one of limitations associated with this technique is that nonlinearities can be produced not only by damage but also by various intrinsic effects such as boundary conditions. The objective of this paper is to demonstrate the application of a nonlinear ultrasonic subharmonic method for detecting fatigue cracks with nonlinear boundary conditions. The fatigue crack was qualitatively modeled as two elastic, frictionless half spaces that enter into contact during vibration and where the contact obeys the basic Hertz contact law...
February 4, 2017: Ultrasonics
https://www.readbyqxmd.com/read/28237656/spectroscopic-studies-of-uv-irradiated-erythrosine-b-thin-films-prepared-by-spin-coating-technique
#6
H M Zeyada, H M El-Mallah, T Atwee, D G El-Damhogi
The spectroscopic studies of erythrosine B thin films manufactured by the spin coating technique have been presented. The spectra of infrared absorption allow characterization of vibrational modes for erythrosine B in powder form, pristine and UV irradiated thin films. The absorption spectra recorded in UV-vis-NIR for pristine films of erythrosine B display two main bands. UV irradiation on erythrosine B films decreased absorbance over the spectra. Indirect allowed transition with optical energy gap of 2.57eV is observed in pristine films...
February 21, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28236336/cardiac-mr-elastography-for-quantitative-assessment-of-elevated-myocardial-stiffness-in-cardiac-amyloidosis
#7
Arvin Arani, Shivaram P Arunachalam, Ian C Y Chang, Francis Baffour, Phillip J Rossman, Kevin J Glaser, Joshua D Trzasko, Kiaran P McGee, Armando Manduca, Martha Grogan, Angela Dispenzieri, Richard L Ehman, Philip A Araoz
PURPOSE: To evaluate if cardiac magnetic resonance elastography (MRE) can measure increased stiffness in patients with cardiac amyloidosis. Myocardial tissue stiffness plays an important role in cardiac function. A noninvasive quantitative imaging technique capable of measuring myocardial stiffness could aid in disease diagnosis, therapy monitoring, and disease prognostic strategies. We recently developed a high-frequency cardiac MRE technique capable of making noninvasive stiffness measurements...
February 25, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28236321/effects-of-local-vibration-and-pulsed-electromagnetic-field-on-bone-fracture-a-comparative-study
#8
Hakkı Murat Bilgin, Ferhat Çelik, Mehmet Gem, Veysi Akpolat, İsmail Yıldız, Aysun Ekinci, Mehmet Siraç Özerdem, Selçuk Tunik
The effectiveness of various therapeutic methods on bone fracture has been demonstrated in several studies. In the present study, we tried to evaluate the effect of local low-magnitude, high-frequency vibration (LMHFV) on rat tibia fracture in comparison with pulsed electromagnetic fields (PEMF) during the healing process. Mid-diaphysis tibiae fractures were induced in 30 Sprague-Dawley rats. The rats were assigned into groups such as control (CONT), LMHFV (15 min/day, 7 days/week), and PEMF (3.5 h/day, 7 days/week) for a three-week treatment...
February 25, 2017: Bioelectromagnetics
https://www.readbyqxmd.com/read/28236186/risk-factors-for-cartilage-damage-and-osteoarthritis-of-the-elbow-joint-case-control-study-and-systematic-literature-review
#9
Gunter Spahn, Jens Uwe Lipfert, Constance Maurer, Bernd Hartmann, Rainer Schiele, Holm-Torsten Klemm, Joachim Grifka, Gunther O Hofmann
INTRODUCTION: This case-control study compares patients with healthy elbows to a group of symptomatic patients with cartilage damage/osteoarthritis. MATERIALS AND METHODS: The control group (n = 126) was recruited during routine medical examinations of patients (general medical offices). Included in the case group were a total of 92 patients who were undergoing arthroscopy as a result of chronic elbow discomfort. All patients were questioned with regard to occupational stress and athletic stress...
February 24, 2017: Archives of Orthopaedic and Trauma Surgery
https://www.readbyqxmd.com/read/28235449/regio-selective-lipase-catalyzed-hydrolysis-of-oxanorbornane-based-sugar-like-amphiphiles-at-air-water-interface-a-polarized-ft-irras-study
#10
Nirod Kumar Sarangi, M Ganesan, K M Muraleedharan, Archita Patnaik
Interfacial hydrolysis of oxanorbornane-based amphiphile (Triol C16) by Candida rugosa lipase was investigated using real-time polarized Fourier transform-infrared reflection absorption spectroscopy (FT-IRRAS). The kinetics of hydrolysis was studied by analyzing the ester carbonyl ν(C=O) stretching vibration band across the two dimensional (2D) array of molecules at the confined interface. In particular, we demonstrate Triol C16 to form Michaelis-Menten type complex, like that of lipid-substrate analogues, where the Triol C16 head group remained accessible to the catalytic triad of the lipase...
February 21, 2017: Chemistry and Physics of Lipids
https://www.readbyqxmd.com/read/28235448/ir-spectroscopy-analysis-of-pancreatic-lipase-related-protein-2-interaction-with-phospholipids-1-discriminative-recognition-of-mixed-micelles-versus-liposomes
#11
Eduardo Mateos-Diaz, Jean-Claude Bakala N'Goma, Deborah Byrne, Sylvie Robert, Frédéric Carrière, Hélène Gaussier
Guinea pig pancreatic lipase-related protein 2 (GPLRP2) is an interesting model enzyme that can hydrolyze a large set of acylglycerols in vitro but displays however some selectivity depending on the supramolecular structure of substrate and the presence of surfactants like bile salts. We showed that GPLRP2 hydrolyzes 1,2-Dipalmitoyl phosphatidylcholine (DPPC) present in mixed micelles with sodium taurodeoxycholate (NaTDC) but not in multilamellar (MLV) and large unilamellar (LUV) vesicles of DPPC. After characterization of these lipid aggregates by dynamic light scattering (DLS), the discriminative recognition of DPPC in DPPC/NaTDC micelles versus MLV and LUV by an inactive variant (S152G) of GPLRP2 to avoid the effect of substrate hydrolysis was investigated using Fourier transform infrared spectroscopy (FTIR)...
February 21, 2017: Chemistry and Physics of Lipids
https://www.readbyqxmd.com/read/28231579/vibration-induced-nystagmus-a-biomarker-for-vestibular-deficits-a-synopsis
#12
Karl-Friedrich Hamann
A review of more than 20 years of experience with vibratory stimulation in vestibular diseases is given. Vibrations in a frequency frame of 30-60 Hz are applied on the mastoid during 20 s. Eye movements are recorded by video-oculography to detect a vibration-induced nystagmus (VIN). A VIN occurs in cases of a side difference between the peripheral vestibular receptors beating to the side of better excitability. In patients with central lesions, a VIN does not appear generally, only exceptionally if the lesion is located laterally in the brain stem...
February 24, 2017: ORL; Journal for Oto-rhino-laryngology and its related Specialties
https://www.readbyqxmd.com/read/28231482/fourier-transform-infrared-and-raman-spectroscopy-in-the-study-of-phase-transitions-in-dipyrazolium-iodide-triiodide-experimental-and-theoretical-analysis
#13
M Węcławik, J Baran, P Durlak, Ł Marciniak, A Piecha-Bisiorek, R Jakubas
The paper presents the Infrared and Raman spectra of the powdered [C3N2H5(+)]2[I(-)∙I3(-)] crystal at the temperature intervals of 11-270K, covering two low-temperature phase transitions: discontinuous at 182/188K (cooling/heating) and continuous at 254K. The research shows that the vibrational states of the pyrazolium cations change significantly during discontinuous phase transition (III→II), while the continuous nature of successive structural transformation is more subtle and displays an insignificant change in the temperature coefficient of numerous vibrations during the II→I PT at 254K...
February 16, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28230297/spectroscopic-observation-of-a-hydrogenated-co-dimer-intermediate-during-co-reduction-on-cu-100-electrodes
#14
Elena Pérez-Gallent, Marta C Figueiredo, Federico Calle-Vallejo, Marc T M Koper
Carbon dioxide and carbon monoxide can be electrochemically reduced to useful products such as ethylene and ethanol on copper electrocatalysts. The process is yet to be optimized and the exact mechanism and the corresponding reaction intermediates are under debate or unknown. In particular, it has been hypothesized that the C-C bond formation proceeds via CO dimerization and further hydrogenation. Although computational support for this hypothesis exists, direct experimental evidence has been elusive. In this work, we detect a hydrogenated dimer intermediate (OCCOH) using Fourier transform infrared spectroscopy at low overpotentials in LiOH solutions...
February 23, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28230197/dynamic-whole-body-vibration-training-a-unique-upstream-treatment-from-the-muscle-to-the-arterial-system-and-central-hemodynamics
#15
Masanori Munakata
No abstract text is available yet for this article.
February 23, 2017: Hypertension Research: Official Journal of the Japanese Society of Hypertension
https://www.readbyqxmd.com/read/28229928/an-expanded-genetic-code-for-probing-the-role-of-electrostatics-in-enzyme-catalysis-by-vibrational-stark-spectroscopy
#16
REVIEW
Jan-Stefan Völler, Hernan Biava, Peter Hildebrandt, Nediljko Budisa
BACKGROUND: To find experimental validation for electrostatic interactions essential for catalytic reactions represents a challenge due to practical limitations in assessing electric fields within protein structures. SCOPE OF REVIEW: This review examines the applications of non-canonical amino acids (ncAAs) as genetically encoded probes for studying the role of electrostatic interactions in enzyme catalysis. MAJOR CONCLUSIONS: ncAAs constitute sensitive spectroscopic probes to detect local electric fields by exploiting the vibrational Stark effect (VSE) and thus have the potential to map the protein electrostatics...
February 13, 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/28229644/emg-activity-of-upper-limb-on-spinal-cord-injury-individuals-during-whole-body-vibration
#17
Uslg Da Silva, H A Villagra, L L Oliva, N F Marconi
Whole-body vibration (WBV) has shown positive results increasing electromyographic (EMG) activity and strength in a healthy population when applied to upper and lower limbs. The aim of this study was to verify if WBV increases the EMG signal of the upper limb muscles in patients with spinal cord injury (SCI). For this study, 15 patients with SCI were selected and one single session of WBV was applied to the upper limb. Five sessions of 30 s at 30 Hz were applied and EMG of anterior deltoid and forearm muscles was measured...
September 2016: Physiol Int
https://www.readbyqxmd.com/read/28229133/towards-enhanced-optical-sensor-performance-seira-and-sers-with-plasmonic-nanostars
#18
O Bibikova, J Haas, A I López-Lorente, A Popov, M Kinnunen, I Meglinski, B Mizaikoff
We report the preparation and characterization of plasmonic chip-based systems comprising self-assembled gold nanostars at silicon substrates that enable concomitantly enhanced Raman (surface enhanced Raman spectroscopy; SERS) and mid-infrared (surface enhanced infrared reflection or absorption spectroscopy; SEIRA) spectral signatures. The high-aspect-ratio structure of gold nanostars provides an increased number of hot spots at their surface, which results in an electric field enhancement around the nanomaterial...
February 23, 2017: Analyst
https://www.readbyqxmd.com/read/28228037/water-dissociation-on-ni-100-ni-110-and-ni-111-surfaces-reaction-path-approach-to-mode-selectivity
#19
H Seenivasan, Bret Jackson, Ashwani K Tiwari
A comparative study of mode-selectivity of water dissociation on Ni(100), Ni(110), and Ni(111) surfaces is performed at the same level of theory using a fully quantum approach based on the reaction path Hamiltonian. Calculations show that the barrier to water dissociation on the Ni(110) surface is significantly lower compared to its close-packed counterparts. Transition states for this reaction on all three surfaces involve the elongation of one of the O-H bonds. A significant decrease in the symmetric stretching and bending mode frequencies near the transition state is observed in all three cases and in the vibrational adiabatic approximation, excitation of these softened modes results in a significant enhancement in reactivity...
February 21, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28228034/vibronic-enhancement-of-excitation-energy-transport-interplay-between-local-and-non-local-exciton-phonon-interactions
#20
Myeong H Lee, Alessandro Troisi
It has been reported in recent years that vibronic resonance between vibrational energy of the intramolecular nuclear mode and excitation-energy difference is crucial to enhance excitation energy transport in light harvesting proteins. Here we investigate how vibronic enhancement induced by vibronic resonance is influenced by the details of local and non-local exciton-phonon interactions. We study a heterodimer model with parameters relevant to the light-harvesting proteins with the surrogate Hamiltonian quantum dynamics method in a vibronic basis...
February 21, 2017: Journal of Chemical Physics
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