keyword
MENU ▼
Read by QxMD icon Read
search

Polarity

keyword
https://www.readbyqxmd.com/read/29166626/non-covalent-interactions-between-thio-caffeine-derivatives-and-water-soluble-porphyrin-in-ethanol-water-environment
#1
Agnieszka Lipke, Magdalena Makarska-Bialokoz, Arleta Sierakowska, Beata Jasiewicz
To determine the binding interactions and ability to form the non-covalent systems, the association process between 5,10,15,20-tetrakis[4-(trimethylammonio)phenyl]-21H,23H-porphine tetra-p-tosylate (H2TTMePP) and a series of five structurally diverse thio-caffeine analogues has been studied in ethanol and ethanol-water solutions, analyzing its absorption and steady-state fluorescence spectra. The porphyrin fluorescence lifetimes in the systems studied were established as well. During the titration with thio-caffeine compounds the slight bathochromic effect and considerable hypochromicity of the porphyrin Soret band maximum can be noted...
November 19, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/29166613/niche-cadherins-control-the-quiescence-to-activation-transition-in-muscle-stem-cells
#2
Aviva J Goel, Marysia-Kolbe Rieder, Hans-Henning Arnold, Glenn L Radice, Robert S Krauss
Many adult stem cells display prolonged quiescence, promoted by cues from their niche. Upon tissue damage, a coordinated transition to the activated state is required because non-physiological breaks in quiescence often lead to stem cell depletion and impaired regeneration. Here, we identify cadherin-mediated adhesion and signaling between muscle stem cells (satellite cells [SCs]) and their myofiber niche as a mechanism that orchestrates the quiescence-to-activation transition. Conditional removal of N-cadherin and M-cadherin in mice leads to a break in SC quiescence, with long-term expansion of a regeneration-proficient SC pool...
November 21, 2017: Cell Reports
https://www.readbyqxmd.com/read/29166593/neural-correlates-of-improvements-in-personality-and-behavior-following-a-neurological-event
#3
Marcie L King, Kenneth Manzel, Joel Bruss, Daniel Tranel
Research on changes in personality and behavior following brain damage has focused largely on negative outcomes, such as increased irritability, moodiness, and social inappropriateness. However, clinical observations suggest that some patients may actually show positive personality and behavioral changes following a neurological event. In the current work, we investigated neuroanatomical correlates of positive personality and behavioral changes following a discrete neurological event (e.g., stroke, benign tumor resection)...
November 19, 2017: Neuropsychologia
https://www.readbyqxmd.com/read/29166573/interaction-of-hsp90-with-phospholipid-model-membranes
#4
Muhan Zhang, Daoying Wang, Pengpeng Li, Chong Sun, Rong Xu, Zhiming Geng, Weimin Xu, Zhaoqi Dai
Heat shock protein 90 (Hsp90) is an essential molecular chaperone with versatile functions in cell homeostatic control under both normal and stress conditions. Hsp90 has been found to be expressed on the cell surface, but the mechanism of Hsp90 association to the membrane remains obscure. In this study, the direct interaction of Hsp90 and phospholipid vesicles was characterized, and the role of Hsp90 on membrane physical state was explored. Using surface plasmon resonance (SPR), we observed a strong interaction between Hsp90 and different compositions of lipid...
November 19, 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/29166570/splenectomy-after-partial-hepatectomy-accelerates-liver-regeneration-in-mice-by-promoting-tight-junction-formation-via-polarity-protein-par-3-apkc
#5
Guoxing Liu, Chengzhi Xie, Yu Fang, Ke Qian, Qiang Liu, Gao Liu, Zhenyu Cao, Huihui Du, Jie Fu, Xundi Xu
AIMS: Several experimental studies have demonstrated that removal of the spleen accelerates liver regeneration after partial hepatectomy. While the mechanism of splenectomy promotes liver regeneration by the improvement of the formation of tight junction and the establishment of hepatocyte polarity is still unknown. MAIN METHODS: We analyzed the cytokines, genes and proteins expression between 70% partial hepatectomy mice (PHx) and simultaneous 70% partial hepatectomy and splenectomy mice (PHs) at predetermined timed points...
November 19, 2017: Life Sciences
https://www.readbyqxmd.com/read/29166560/analytical-challenges-and-recent-advances-in-mass-spectrometry-based-lipidomics
#6
Yepy Hardi Rustam, Gavin Edmund Reid
Although no internationally accepted consensus definition exists, lipids can be broadly defined as "fatty acids and their derivatives, and substances related biosynthetically or functionally to these compounds". Lipids play critical roles as (i) the major structural components of biological membranes, and as functional and regulatory components of membrane protein signaling, (ii) bioactive intra- and inter-cellular signaling molecules, and (iii) energy storage molecules for the maintenance of energy homeostasis...
November 22, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/29166412/mir-195-inhibits-macrophages-pro-inflammatory-profile-and-impacts-the-crosstalk-with-smooth-muscle-cells
#7
Joao Paulo Bras, Andreia Machado Silva, George A Calin, Mario Adolfo Barbosa, Susana Gomes Santos, Maria Ines Almeida
Macrophages are a main component of atherosclerotic plaques. Recent studies suggest that pro-inflammatory M1 macrophages are pro-atherogenic while M2 macrophages promote plaque stability. Moreover, toll-like receptor signalling pathways are implicated in atherosclerotic plaque formation, evolution and regression. We propose microRNAs as key regulators of these processes. In this context, our goal is to promote inflammation resolution using miR-195 to reduce M1-like macrophage polarization and to evaluate the molecular mechanisms underlying such effect, as well as to explore the functional consequences for smooth muscle cell recruitment...
2017: PloS One
https://www.readbyqxmd.com/read/29166109/temperature-and-chain-length-dependence-of-ultrafast-vibrational-dynamics-of-thiocyanate-in-alkylimidazolium-ionic-liquids-a-random-walk-on-a-rugged-energy-landscape
#8
Thomas Brinzer, Sean Garrett-Roe
Ultrafast two-dimensional infrared spectroscopy of a thiocyanate vibrational probe (SCN(-)) was used to investigate local dynamics in alkylimidazolium bis-[trifluoromethylsulfonyl]imide ionic liquids ([Imn,1][Tf2N], n = 2, 4, 6) at temperatures from 5 to 80 °C. The rate of frequency fluctuations reported by SCN(-) increases with increasing temperature and decreasing alkyl chain length. Temperature-dependent correlation times scale proportionally to temperature-dependent bulk viscosities of each ionic liquid studied...
November 21, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/29166106/nodeless-vibrational-amplitudes-and-quantum-nonadiabatic-dynamics-in-the-nested-funnel-for-a-pseudo-jahn-teller-molecule-or-homodimer
#9
William K Peters, Vivek Tiwari, David M Jonas
The nonadiabatic states and dynamics are investigated for a linear vibronic coupling Hamiltonian with a static electronic splitting and weak off-diagonal Jahn-Teller coupling through a single vibration with a vibrational-electronic resonance. With a transformation of the electronic basis, this Hamiltonian is also applicable to the anti-correlated vibration in a symmetric homodimer with marginally strong constant off-diagonal coupling, where the non-adiabatic states and dynamics model electronic excitation energy transfer or self-exchange electron transfer...
November 21, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/29166104/rapid-spectro-polarimetry-to-probe-molecular-symmetry-in-multiplex-coherent-anti-stokes-raman-scattering
#10
Thomas Würthwein, Maximilian Brinkmann, Tim Hellwig, Carsten Fallnich
We present the simultaneous detection of the spectrum and the complete polarization state of a multiplex coherent anti-Stokes Raman scattering signal with a fast division-of-amplitude spectro-polarimeter. The spectro-polarimeter is based on a commercial imaging spectrograph, a birefringent wedge prism, and a segmented polarizer. Compared to the standard rotating-retarder fixed-analyzer spectro-polarimeter, only a single measurement is required and an up to 21-fold reduced acquisition time is shown. The measured Stokes parameters allow us to differentiate between vibrational symmetries and to determine the depolarization ratio ρ by data post-processing...
November 21, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/29166099/long-range-dipolar-order-and-dispersion-forces-in-polar-liquids
#11
Quinn Alexander Besford, Andrew Joseph Christofferson, Maoyuan Liu, Irene Yarovsky
Complex solvation phenomena, such as specific ion effects, occur in polar liquids. Interpretation of these effects in terms of structure and dispersion forces will lead to a greater understanding of solvation. Herein, using molecular dynamics, we probe the structure of polar liquids through specific dipolar pair correlation functions that contribute to the potential of mean force that is "felt" between thermally rotating dipole moments. It is shown that unique dipolar order exists at separations at least up to 20 Å for all liquids studied...
November 21, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/29166095/computer-simulations-of-alkali-acetate-solutions-accuracy-of-the-forcefields-in-difference-concentrations
#12
Emma Ahlstrand, Julio Zukerman Schpector, Ran Friedman
When proteins are solvated in electrolyte solutions that contain alkali ions, the ions interact mostly with carboxylates on the protein surface. Correctly accounting for alkali-carboxylate interactions is thus important for realistic simulations of proteins. Acetates are the simplest carboxylates that are amphipathic, and experimental data for alkali acetate solutions are available and can be compared with observables obtained from simulations. We carried out molecular dynamics simulations of alkali acetate solutions using polarizable and non-polarizable forcefields and examined the ion-acetate interactions...
November 21, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/29166090/analytical-expression-for-the-tunnel-current-through-the-redox-mediated-tunneling-contact-in-the-case-of-the-adiabatic-electron-transfer-at-one-of-the-working-electrodes-and-any-possible-type-of-the-electron-transfer-at-the-other-electrode
#13
Igor G Medvedev
We study the tunnel current through a one-level redox molecule immersed into the electrolyte solution for the case when the coupling of the molecule to one of the working electrodes is strong while it is arbitrary to the other electrode. Using the Feynman-Vernon influence functional theory and the perturbation expansion of the effective action of the classical oscillator coupled both to the valence level of the redox molecule and to the thermal bath representing the classical fluctuations of the polarization of the solvent, we obtain, following the canonical way, the Langevin equation for the oscillator...
November 21, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/29166063/hard-hard-coupling-assisted-anomalous-magnetoresistance-effect-in-amine-ended-single-molecule-magnetic-junction
#14
Y-H Tang, C-J Lin, K-R Chiang
We proposed a single-molecule magnetic junction (SMMJ), composed of a dissociated amine-ended benzene sandwiched between two Co tip-like nanowires. To better simulate the break junction technique for real SMMJs, the first-principles calculation associated with the hard-hard coupling between a amine-linker and Co tip-atom is carried out for SMMJs with mechanical strain and under an external bias. We predict an anomalous magnetoresistance (MR) effect, including strain-induced sign reversal and bias-induced enhancement of the MR value, which is in sharp contrast to the normal MR effect in conventional magnetic tunnel junctions...
June 14, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/29166056/understanding-the-effects-of-electronic-polarization-and-delocalization-on-charge-transport-levels-in-oligoacene-systems
#15
Christopher Sutton, Naga Rajesh Tummala, Travis Kemper, Saadullah G Aziz, John Sears, Veaceslav Coropceanu, Jean-Luc Brédas
Electronic polarization and charge delocalization are important aspects that affect the charge-transport levels in organic materials. Here, using a quantum mechanical/embedded-charge (QM/EC) approach based on a combination of the long-range corrected ωB97X-D exchange-correlation functional (QM) and charge model 5 (CM5) point-charge model (EC), we evaluate the vertical detachment energies and polarization energies of various sizes of crystalline and amorphous anionic oligoacene clusters. Our results indicate that QM/EC calculations yield vertical detachment energies and polarization energies that compare well with the experimental values obtained from ultraviolet photoemission spectroscopy measurements...
June 14, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/29166049/interaction-of-rigid-c3n-with-he-potential-energy-surface-bound-states-and-rotational-spectrum
#16
Miguel Lara-Moreno, Thierry Stoecklin, Philippe Halvick
A two-dimensional rigid rotor model of the potential energy surface is developed for the collision of C3N(-) with He. Ab initio calculations are performed at the coupled cluster level with single and double excitations and using a perturbative treatment of triple excitations. An augmented correlation consistent polarized valence quadruple zeta basis set complemented with a set of mid-bond functions is chosen for these calculations. The global T-shaped minimum (De = 62.114 cm(-1)) is found at the intermolecular distance R = 6...
June 14, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/29166010/conformational-dynamics-of-asparagine-at-coiled-coil-interfaces
#17
Franziska Thomas, Ai Niitsu, Alain Oregioni, Gail J Bartlett, Derek N Woolfson
Coiled coils (CCs) are among the best-understood protein folds. Nonetheless, there are gaps in our knowledge of CCs. Notably, CCs are likely to be structurally more dynamic than often considered. Here, we explore this in an abundant class of CCs, parallel dimers, focusing on polar asparagine (Asn) residues in the hydrophobic interface. It is well documented that such inclusions discriminate between different CC oligomers, which has been rationalized in terms of whether the Asn can make side-chain hydrogen bonds or not...
November 22, 2017: Biochemistry
https://www.readbyqxmd.com/read/29165931/remarkable-differences-in-spin-couplings-for-various-self-paired-dimers-of-ring-expansion-radicalized-uracil-a-basis-for-the-design-of-magnetic-anisotropic-assembly
#18
Peiwen Zhao, Yuxiang Bu
In this work, we examine the spin coupling properties of ten radicalized uracil (rU) dimers with different H-bonding modes. Each rU has four double-H-bonding sites (2 at the Watson-Crick face, WC1 and WC2; a Hoogsteen site, HO; a minor groove site, MI) and self pairing leads to 10 dimers (rU-rU) featuring diradicals. All these diradicals exhibit distinctly different spin coupling characters (ferromagnetic/FM versus antiferromagnetic/AFM and large versus small magnitude spin couplings), indicating remarkable magnetic coupling anisotropy of rU...
November 22, 2017: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/29165902/multi-contrast-endomyocardial-imaging-by-single-channel-high-resolution-cross-polarization-optical-coherence-tomography
#19
Xinwen Yao, Yu Gan, Yuye Ling, Charles C Marboe, Christine P Hendon
A single-channel high-resolution cross-polarization (CP) optical coherence tomography (OCT) system is presented for multi-contrast imaging of human myocardium in one-shot measurement. The intensity contrast and functional contrasts, including the ratio between the cross- and co- polarization channels as well as the cumulative retardation, are reconstructed from the CP-OCT readout. By comparing the CP-OCT results with histological analysis, it is shown that the system can successfully delineate micro-structures in the myocardium and differentiate the fibrotic myocardium from normal or ablated myocardium based the functional contrasts provided by the CP-OCT system...
November 22, 2017: Journal of Biophotonics
https://www.readbyqxmd.com/read/29165453/structural-and-electronic-properties-of-barbituric-acid-and-melamine-containing-ribonucleosides-as-plausible-components-of-prebiotic-rna-implications-for-prebiotic-self-assembly
#20
Sarabjeet Kaur, Purshotam Sharma, Stacey D Wetmore
The RNA world hypothesis assumes that RNA was the first informational polymer that originated from prebiotic chemical soup. However, since the reaction of d-ribose with canonical nucleobases (A, C, G and U) fails to yield ribonucleosides (rNs) in substantial amounts, the spontaneous origin of rNs and the subsequent synthesis of RNA remains an unsolved mystery. To this end, it has been suggested that RNA may have evolved from primitive genetic material (preRNA) composed of simpler prebiotic heterocycles that spontaneously form glycosidic bonds with ribose...
November 22, 2017: Physical Chemistry Chemical Physics: PCCP
keyword
keyword
38097
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"