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https://www.readbyqxmd.com/read/29775998/high-pressure-raman-study-of-type-i-collagen
#1
Amalia Maria Paschou, Maria Katsikini, Dimitrios Christofilos, John Arvanitidis, Sotirios Ves
The high pressure response of type-I collagen from bovine Achilles tendon is investigated with micro-Raman spectroscopy. Fluorinert™ and methanol-ethanol mixtures were used as pressure transmitting media (PTM) in a diamond anvil cell. The Raman spectrum of collagen is dominated by three bands centred at approximately 1450, 1660 and 2930 cm-1 , attributed to C-H deformation, C=O stretching of the peptide bond (amide-I band) and C-H stretching modes, respectively. Upon pressure increase, using Fluorinert™ as PTM, a shift towards higher frequencies of the C-H stretching and deformation peaks is observed...
May 18, 2018: FEBS Journal
https://www.readbyqxmd.com/read/29775864/exogenous-hydrogen-peroxide-inhibits-primary-root-gravitropism-by-regulating-auxin-distribution-during-arabidopsis-seed-germination
#2
Lina Zhou, Hongzhou Hou, Tao Yang, Yuke Lian, Yan Sun, Zhiyuan Bian, Chongying Wang
Hydrogen peroxide (H2 O2 ) is the key factor in many physiological and metabolic processes in plants. During seed germination, exogenous H2 O2 application influences gravitropism and induces curvature of the primary root in grass pea and pea seedlings. However, it remains unclear whether and how this happens in the model plant Arabidopsis thaliana. In the present study, the effect of exogenous H2 O2 on the gravitropic response of primary roots during Arabidopsis seed germination was studied using histology and molecular biology approaches...
May 15, 2018: Plant Physiology and Biochemistry: PPB
https://www.readbyqxmd.com/read/29775855/dual-core-all-fiber-integrated-immunosensor-for-detection-of-protein-antigens
#3
Karol Wysokiński, Dawid Budnicki, Janusz Fidelus, Łukasz Szostkiewicz, Łukasz Ostrowski, Micha Murawski, Marcin Staniszewski, Magdalena Staniszewska, Marek Napierała, Tomasz Nasiłowski
An optical fiber interferometric microprobe for detection of specific proteins is presented in this paper. The microprobe is an all-fiber device, which is based on Michelson interferometer configuration, which allows for detection of protein antigens in an analyzed solution thanks to antibodies immobilized on the sensor surface. The interferometer is made of dual core fiber and has a precisely formed arm length difference, achieved by splicing a fragment of polarization maintaining fiber to one of the cores...
May 9, 2018: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/29775816/understanding-the-role-of-hydrogen-bonding-in-the-aggregation-of-fumed-silica-particles-in-triglyceride-solvents
#4
Catherine P Whitby, Melinda Krebsz, Samuel J Booty
HYPOTHESIS: Fumed silica particles are thought to thicken organic solvents into gels by aggregating to form networks. Hydrogen bonding between silanol groups on different particle surfaces causes the aggregation. The gel structure and hence flow behaviour is altered by varying the proportion of silanol groups on the particle surfaces. However, characterising the gel using rheology measurements alone is not sufficient to optimise the aggregation. We have used confocal microscopy to characterise the changes in the network microstructure caused by altering the particle surface chemistry...
May 12, 2018: Journal of Colloid and Interface Science
https://www.readbyqxmd.com/read/29775537/amplification-of-dynamic-nuclear-polarization-at-200-ghz-by-arbitrary-pulse-shaping-of-the-electron-spin-saturation-profile
#5
Ilia Kaminker, Songi Han
Dynamic nuclear polarization (DNP) takes center stage in nuclear magnetic resonance (NMR) as a tool to amplify its signal by orders of magnitude through the transfer of polarization from electron to nuclear spins. In contrast to modern NMR and electron paramagnetic resonance (EPR) that extensively rely on pulses for spin manipulation in the time domain, the current mainstream DNP technology exclusively relies on monochromatic continuous wave (CW) irradiation. This study introduces arbitrary phase shaped pulses that constitute a train of coherent chirp pulses in the time domain at 200 GHz (7 Tesla) to dramatically enhance the saturation bandwidth and DNP performance compared to CW DNP, yielding up to 500-fold in NMR signal enhancements...
May 18, 2018: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/29775478/treadmilling-analysis-reveals-new-insights-into-dynamic-ftsz-ring-architecture
#6
Diego A Ramirez-Diaz, Daniela A García-Soriano, Ana Raso, Jonas Mücksch, Mario Feingold, Germán Rivas, Petra Schwille
FtsZ, the primary protein of the bacterial Z ring guiding cell division, has been recently shown to engage in intriguing treadmilling dynamics along the circumference of the division plane. When coreconstituted in vitro with FtsA, one of its natural membrane anchors, on flat supported membranes, these proteins assemble into dynamic chiral vortices compatible with treadmilling of curved polar filaments. Replacing FtsA by a membrane-targeting sequence (mts) to FtsZ, we have discovered conditions for the formation of dynamic rings, showing that the phenomenon is intrinsic to FtsZ...
May 18, 2018: PLoS Biology
https://www.readbyqxmd.com/read/29775391/understanding-physical-mechanism-of-low-level-microwave-radiation-effect
#7
Hiie Hinrikus, Maie Bachmann, Jaanus Lass
PURPOSE: This topic review aims to explain the mechanism of low-level microwave radiation effect based on published research results. The review presents the analysis of theoretical and experimental results comprising underlying physics and derived biological-physiological consequences supported by experimental data. CONCLUSIONS: The rotation of dipolar molecules causes polarization of dielectric medium and restructuring of hydrogen bonds between these molecules...
May 18, 2018: International Journal of Radiation Biology
https://www.readbyqxmd.com/read/29775390/polarization-and-distribution-of-tumor-associated-macrophages-and-cox-2-expression-in-basal-cell-carcinoma-of-the-ocular-adnexae
#8
Ute Kaiser, Karin U Loeffler, Jennifer Nadal, Frank G Holz, Martina C Herwig-Carl
PURPOSE: Basal cell carcinoma (BCC) is a locally invasive skin tumor which can be subdivided into a circumscribed nodular and an invasive fibrosing subtype. There is increasing evidence that macrophages play an important role in interacting between tumor cells and their microenvironment, thereby affecting not only the invasive potential but also the patients' prognosis. Thus, we wanted to compare these two BCC variants with regard to tumor-related inflammation, COX-2 expression, distribution and polarization of tumor-associated macrophages...
May 18, 2018: Current Eye Research
https://www.readbyqxmd.com/read/29775372/polar-kerr-effect-from-time-reversal-symmetry-breaking-in-the-heavy-fermion-superconductor-pros_-4-sb_-12
#9
E M Levenson-Falk, E R Schemm, Y Aoki, M B Maple, A Kapitulnik
We present polar Kerr effect measurements of the filled skutterudite superconductor PrOs_{4}Sb_{12}. Simultaneous ac susceptibility measurements allow us to observe the superconducting transition under the influence of heating from the optical beam. A nonzero Kerr angle θ_{K} develops below the superconducting transition, saturating at ∼300  nrad at low temperatures. This result is repeated across several measurements of multiple samples. By extrapolating the measured θ_{K}(T) to zero optical power, we are able to show that the Kerr angle onset temperature in one set of measurements is consistent with the transition to the B phase at T_{C2}...
May 4, 2018: Physical Review Letters
https://www.readbyqxmd.com/read/29775371/langevin-dynamics-with-spatial-correlations-as-a-model-for-electron-phonon-coupling
#10
A Tamm, M Caro, A Caro, G Samolyuk, M Klintenberg, A A Correa
Stochastic Langevin dynamics has been traditionally used as a tool to describe nonequilibrium processes. When utilized in systems with collective modes, traditional Langevin dynamics relaxes all modes indiscriminately, regardless of their wavelength. We propose a generalization of Langevin dynamics that can capture a differential coupling between collective modes and the bath, by introducing spatial correlations in the random forces. This allows modeling the electronic subsystem in a metal as a generalized Langevin bath endowed with a concept of locality, greatly improving the capabilities of the two-temperature model...
May 4, 2018: Physical Review Letters
https://www.readbyqxmd.com/read/29775342/boundaries-control-collective-dynamics-of-inertial-self-propelled-robots
#11
A Deblais, T Barois, T Guerin, P H Delville, R Vaudaine, J S Lintuvuori, J F Boudet, J C Baret, H Kellay
Simple ingredients, such as well-defined interactions and couplings for the velocity and orientation of self-propelled objects, are sufficient to produce complex collective behavior in assemblies of such entities. Here, we use assemblies of rodlike robots made motile through self-vibration. When confined in circular arenas, dilute assemblies of these rods act as a gas. Increasing the surface fraction leads to a collective behavior near the boundaries: polar clusters emerge while, in the bulk, gaslike behavior is retained...
May 4, 2018: Physical Review Letters
https://www.readbyqxmd.com/read/29775334/observation-of-polarization-vortices-in-momentum-space
#12
Yiwen Zhang, Ang Chen, Wenzhe Liu, Chia Wei Hsu, Bo Wang, Fang Guan, Xiaohan Liu, Lei Shi, Ling Lu, Jian Zi
The vortex, a fundamental topological excitation featuring the in-plane winding of a vector field, is important in various areas such as fluid dynamics, liquid crystals, and superconductors. Although commonly existing in nature, vortices were observed exclusively in real space. Here, we experimentally observed momentum-space vortices as the winding of far-field polarization vectors in the first Brillouin zone of periodic plasmonic structures. Using homemade polarization-resolved momentum-space imaging spectroscopy, we mapped out the dispersion, lifetime, and polarization of all radiative states at the visible wavelengths...
May 4, 2018: Physical Review Letters
https://www.readbyqxmd.com/read/29775330/constraining-alternative-theories-of-gravity-using-pulsar-timing-arrays
#13
Neil J Cornish, Logan O'Beirne, Stephen R Taylor, Nicolás Yunes
The opening of the gravitational wave window by ground-based laser interferometers has made possible many new tests of gravity, including the first constraints on polarization. It is hoped that, within the next decade, pulsar timing will extend the window by making the first detections in the nanohertz frequency regime. Pulsar timing offers several advantages over ground-based interferometers for constraining the polarization of gravitational waves due to the many projections of the polarization pattern provided by the different lines of sight to the pulsars, and the enhanced response to longitudinal polarizations...
May 4, 2018: Physical Review Letters
https://www.readbyqxmd.com/read/29775314/qm-mm-simulations-with-the-gaussian-electrostatic-model-a-density-based-polarizable-potential
#14
Hatice Gokcan, Eric Granville Kratz, Thomas A Darden, Jean-Philip Piquemal, Gerardo Andres Cisneros
The use of advanced polarizable potentials in Quantum Mechanical/Molecular Mechanical (QM/MM) simulations have been shown to improve the overall accuracy of the calculation. We have developed a density-based potential called the Gaussian Electrostatic Model (GEM), which has been shown to provide very accurate environments for QM wavefunctions in QM/MM. In this contribution we present a new implementation of QM/GEM that extends our implementation to include all components (Coulomb, exchange-repulsion, polarization, and dispersion) for the total inter-molecular interaction energy in QM/MM calculations, except for the charge-transfer term...
May 18, 2018: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/29775313/force-field-for-water-based-on-neural-network
#15
Hao Wang, Weitao Yang
We developed a novel neural network based force field for water based on training with high level ab initio theory. The force field was built based on electrostatically embedded many-body expansion method truncated at binary interactions. Many-body expansion method is a common strategy to partition the total Hamiltonian of large systems into a hierarchy of few-body terms. Neural networks were trained to represent electrostatically embedded one-body and two-body interactions, which require as input only one and two water molecule calculations at the level of ab initio electronic structure method CCSD/aug-cc-pVDZ embedded in the molecular mechanics water environment, making it efficient as a general force field construction approach...
May 18, 2018: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/29775293/mitigating-interfacial-potential-drop-of-cathode-solid-electrolyte-via-ionic-conductor-layer-to-enhance-interface-dynamics-for-solid-batteries
#16
Jia-Yan Liang, Xian-Xiang Zeng, Xu-Dong Zhang, Peng-Fei Wang, Jing-Yuan Ma, Ya-Xia Yin, Xiong-Wei Wu, Yu-Guo Guo, Lijun Wan
The rapid capacity decay caused by the poor contact and large polari-zation at the interface between the cathode and solid electrolytes is still a big challenge to overcome for high-power-density solid batteries. In this study, a superior Li+ conductive transition layer Li1.4Al0.4Ti1.6(PO4)3 is introduced to coat LiNi0.6Co0.2Mn0.2O2, as a model cathode, to mitigate polarization and enhance dynamic characteristics. The critical attribute for such superior dynamics is investigated by the atomic force microscopy with boundary potential analysis, revealing that the formed interfacial transition layer provides a gradual potential slope and sustain-released polarization, and endows the battery with improved cycling stability (90% after 100 cycles) and excellent rate capability (116 mA h g-1 at 2C) at room temperature, which enlightens the comprehension of interface engineering in the future solid batteries systems...
May 18, 2018: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/29775272/remarkable-enhancement-in-the-photoelectric-performance-of-uniform-flower-like-mesoporous-fe3o4-wrapped-in-nitrogen-doped-graphene-networks
#17
Jixin Yao, Kang Zhang, Wen Wang, Xueqin Zuo, Qun Yang, Huaibao Tang, Mingzai Wu, Guang Li
The porous structure and excellent specific surface area are superior for use as a counter electrode (CE) material. In addition, N-doped graphene possesses a remarkable electron-transfer pathway and many active sites. Therefore, a novel idea is to wrap uniform flower-like mesoporous Fe3O4 (Fe3O4UFM) in a N-doped graphene (N-RGO) network structure to enhance the power conversion efficiency (PCE). The hybrid materials of Fe3O4UFM@N-RGO are first used as a CE in dye-sensitized solar cells (DSSCs), showing a preeminent conductive interconnected 3D porous structure with more catalytic activity sites and a better ability for and a faster reaction rate of charge transfer, resulting in quicker reduction of I_3^- than Pt...
May 18, 2018: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/29775232/mannosylinositol-phosphorylceramides-and-ergosterol-coodinately-maintain-cell-wall-integrity-in-the-yeast-saccharomyces-cerevisiae
#18
Seiya Tanaka, Motohiro Tani
In the yeast Saccharomyces cerevisiae, complex sphingolipids have three types of polar head group, and breakdown of the normal composition causes several cellular dysfunctions. Previously we found that loss of biosynthesis of mannosylinositol phosphorylceramide (MIPC) causes a defect in cell wall integrity. In this study, we screened for multicopy suppressor genes that rescue the defect in cell wall integrity in cells lacking MIPC synthases (Sur1 and Csh1), and found that the defect is partly suppressed by upregulation of ergosterol biosynthesis...
May 18, 2018: FEBS Journal
https://www.readbyqxmd.com/read/29775215/development-of-a-fast-ce-method-for-high-throughput-screening-of-ecto-5-nucleotidase-inhibitors
#19
Rabia Raza, Yu Bai, Huwei Liu
Overexpression of ecto-5'-nucleotidase is found to be linked to cancer progression and other diseases which makes screening of its inhibitors on demand. Unfortunately, there is scarcity of reported ecto-5'-nucleotidase inhibitors because of unavailability of simple, fast and efficient methods to study its inhibition. In this study, we have developed a very fast, reverse polarity capillary electrophoresis based method for screening of ecto-5'-nucleotidase inhibitors. Both EOF and electrophoretic mobility were maintained in same direction by dynamically coating lining of capillary and applying negative voltage, resulting in appearance of both adenosine monophosphate (AMP) and adenosine peaks in less than two minutes...
May 18, 2018: Electrophoresis
https://www.readbyqxmd.com/read/29775190/phosphonium-carbosilane-dendrimers-interaction-with-a-simple-biological-membrane-model
#20
Dominika Wrobel, Radka Kubikova, Monika Müllerová, Tomas Strašák, Květoslav RůŽička, Michal Fulem, Jan Maly
The influence of three generations of five different phosphonium carbosilane dendrimers and one ammonium carbosilane dendrimer as a reference (PMe3, PBu3, P(Et2)2(CH2)3OH, PPh3, P(MeOPh)3 and NMe3, peripheral functional groups) on dimyristoylphosphatidylcholine (DMPC) or a lipid mixture dimyristoylphosphatidylcholine/dimyristoylphosphatidylglycerol (DMPC/DMPG) of liposomes was studied by fluorescence polarization measurements and differential scanning calorimetry. All types of dendrimers interacted with neutral as well as negatively charged liposomes, but the strength and observed influence were different...
May 18, 2018: Physical Chemistry Chemical Physics: PCCP
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