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https://www.readbyqxmd.com/read/28343237/actogram-analysis-of-free-flying-migratory-birds-new-perspectives-based-on-acceleration-logging
#1
REVIEW
Johan Bäckman, Arne Andersson, Lykke Pedersen, Sissel Sjöberg, Anders P Tøttrup, Thomas Alerstam
The use of accelerometers has become an important part of biologging techniques for large-sized birds with accelerometer data providing information about flight mode, wing-beat pattern, behaviour and energy expenditure. Such data show that birds using much energy-saving soaring/gliding flight like frigatebirds and swifts can stay airborne without landing for several months. Successful accelerometer studies have recently been conducted also for free-flying small songbirds during their entire annual cycle. Here we review the principles and possibilities for accelerometer studies in bird migration...
March 25, 2017: Journal of Comparative Physiology. A, Neuroethology, Sensory, Neural, and Behavioral Physiology
https://www.readbyqxmd.com/read/28332812/hierarchical-nico2s4-nife-ldh-heterostructures-supported-on-nickel-foam-for-enhanced-overall-water-splitting-activity
#2
Jia Liu, Jinsong Wang, Bao Zhang, Yunjun Ruan, Lin Lv, Xiao Ji, Kui Xu, Ling Miao, Jianjun Jiang
Low cost and high efficient bifunctional electrocatalysts for the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) are intensively investigated for overall water splitting. Herein, we combined experimental researches with first-principles calculations based on density functional theory (DFT) to engineer the NiCo2S4@NiFe LDH heterostructures interface for enhancing overall water splitting activity. The DFT calculations exhibit a strong interaction and charge transfer between NiCo2S4 and NiFe LDH, which change the interfacial electronic structure and surface reactivity...
March 23, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28330356/grand-canonical-electronic-density-functional-theory-algorithms-and-applications-to-electrochemistry
#3
Ravishankar Sundararaman, William A Goddard, Tomas A Arias
First-principles calculations combining density-functional theory and continuum solvation models enable realistic theoretical modeling and design of electrochemical systems. When a reaction proceeds in such systems, the number of electrons in the portion of the system treated quantum mechanically changes continuously, with a balancing charge appearing in the continuum electrolyte. A grand-canonical ensemble of electrons at a chemical potential set by the electrode potential is therefore the ideal description of such systems that directly mimics the experimental condition...
March 21, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28322397/effect-of-an-acetylene-bond-on-hydrogen-adsorption-in-diamond-like-carbon-allotropes-from-first-principles-to-atomic-simulation
#4
Xuanjun Wu, Lei Li, Tiange Fang, YeTong Wang, Weiquan Cai, Zhonghua Xiang
By inserting an acetylene bond into the organic linkers of porous materials, hydrogen storage can be significantly enhanced; however, the mechanism of this enhancement remains elusive. Herein, we developed a new diamond-like carbon allotrope (referred as diamond-like diacetylene a.k.a. DDA) with medium pores constructed by inserting -C[triple bond, length as m-dash]C-C[triple bond, length as m-dash]C- ligands into the -C-C- bonds of diamond. The structural, mechanical, and electrical properties, as well as hydrogen storage capacities were investigated for this novel material using density functional theory and Monte Carlo simulations...
March 21, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28319663/2h-ws2-quantum-dots-produced-by-modulating-the-dimension-and-phase-of-1t-nanosheets-for-antibody-free-optical-sensing-of-neurotransmitters
#5
Man-Jin Kim, Su-Ji Jeon, Tae Woog Kang, Jong-Min Ju, DaBin Yim, Hye-In Kim, Jung Hyun Park, Jong-Ho Kim
Modulating the dimensions and phases of transition metal dichalcogenides is of great interest to enhance their intrinsic properties or to create new physicochemical properties. Herein, we report an effective approach to synthesize 2H-WS2 quantum dots (QDs) via the dimension and phase engineering of 1T-WS2 nanosheets. The solvothermal reaction of chemically-exfoliated 1T-WS2 nanosheets in N-methyl-2-pyrrolidone (NMP) under an N2 atmosphere induced their chopping and phase transition at lower temperature to produce 2H-WS2 QDs with a high quantum yield (5...
March 20, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28318251/molecular-simulation-studies-on-the-binding-selectivity-of-type-i-inhibitors-in-the-complexes-with-ros1-versus-alk
#6
Yuanxin Tian, Yonghuan Yu, Yudong Shen, Hua Wan, Shan Chang, Tingting Zhang, Shanhe Wan, Jiajie Zhang
ROS1 and ALK are promising targets of anti-cancer drugs for non small cell lung cancer. Since they have 49% amide acid sequence homology in the kinases domain and 77% identity at the ATP binding area, some ALK inhibitors also showed some significant responses for ROS1 in the clinical trial, such as the type-I binding inhibitor crizotinib and PF-06463922. As a newly therapeutic target, selective ROS1 inhibitor is relative rarely. Moreover, the molecular basis for the selectivity of ROS1 versus ALK still remains unclear...
March 20, 2017: Journal of Chemical Information and Modeling
https://www.readbyqxmd.com/read/28297930/analysis-of-spontaneous-oscillations-for-a-three-state-power-stroke-model
#7
Takumi Washio, Toshiaki Hisada, Seine A Shintani, Hideo Higuchi
Our study considers the mechanism of the spontaneous oscillations of molecular motors that are driven by the power stroke principle by applying linear stability analysis around the stationary solution. By representing the coupling equation of microscopic molecular motor dynamics and mesoscopic sarcomeric dynamics by a rank-1 updated matrix system, we derived the analytical representations of the eigenmodes of the Jacobian matrix that cause the oscillation. Based on these analytical representations, we successfully derived the essential conditions for the oscillation in terms of the rate constants of the power stroke and the reversal stroke transitions of the molecular motor...
February 2017: Physical Review. E
https://www.readbyqxmd.com/read/28296416/nuclear-quantum-effects-on-aqueous-electron-attachment-and-redox-properties
#8
Vladimir V Rybkin, Joost VandeVondele
Nuclear quantum effects (NQE) on the reduction and oxidation properties of small aqueous species (CO2, HO2, and O2) are quantified and rationalized by first principles molecular dynamics and thermodynamic integration. Vertical electron attachment, or electron affinity, and detachment energies (VEA and VDE) are strongly affected by NQE, decreasing in absolute value by 0.3 eV going from a classical to a quantum description of the nuclei. The effect is attributed to NQE that lessen the solvent response upon oxidation/reduction...
March 15, 2017: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/28294255/photocatalytic-oxygen-evolution-from-low-bandgap-conjugated-microporous-polymer-nanosheets-a-combined-first-principles-calculation-and-experimental-study
#9
Lei Wang, Yangyang Wan, Yanjun Ding, Yuchen Niu, Yujie Xiong, Xiaojun Wu, Hangxun Xu
Nanostructured semiconducting polymers have emerged as a very promising class of metal-free photocatalytic materials for solar water splitting. However, they generally exhibit low efficiency and lack the ability to utilize long-wavelength photons in a photocatalytic oxygen evolution reaction (OER). Here, based on first-principles calculations, we reveal that the two-dimensional (2D) aza-fused conjugated microporous polymer (aza-CMP) with a honeycomb network is a semiconductor with novel layer-dependent electronic properties...
March 15, 2017: Nanoscale
https://www.readbyqxmd.com/read/28290655/non-equilibrium-catalyst-materials-stabilized-by-the-aerogel-effect-solvent-free-and-continuous-synthesis-of-gamma-alumina-with-hierarchical-porosity
#10
Kay Hagedorn, Ulrich Bahnmüller, Andreas Schachtschneider, Maren Frei, Wenyu Li, Jörn Schmedt Auf der Günne, Sebastian Polarz
Heterogeneous catalysis can be understood as a phenomenon which strongly relies on the occurrence of thermodynamically less favorable surface motifs like defects or high-energy planes. Because it is very difficult to control such parameters, an interesting approach is to explore metastable polymorphs of the respective solids. The latter is not an easy task as well because the emergence of polymorphs is dictated by kinetic control and materials with high surface area are required. Further, an inherent problem is that high temperatures required for many catalytic reactions can also induce the transformation to the thermodynamically stable modification...
March 14, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28282439/iterative-free-energy-optimization-for-recurrent-neural-networks-inferno
#11
Alexandre Pitti, Philippe Gaussier, Mathias Quoy
The intra-parietal lobe coupled with the Basal Ganglia forms a working memory that demonstrates strong planning capabilities for generating robust yet flexible neuronal sequences. Neurocomputational models however, often fails to control long range neural synchrony in recurrent spiking networks due to spontaneous activity. As a novel framework based on the free-energy principle, we propose to see the problem of spikes' synchrony as an optimization problem of the neurons sub-threshold activity for the generation of long neuronal chains...
2017: PloS One
https://www.readbyqxmd.com/read/28281230/identifying-the-interaction-of-vancomycin-with-novel-ph-responsive-lipids-as-antibacterial-biomaterials-via-accelerated-molecular-dynamics-and-binding-free-energy-calculations
#12
Shaimaa Ahmed, Suresh B Vepuri, Mahantesh Jadhav, Rahul S Kalhapure, Thirumala Govender
Nano-drug delivery systems have proven to be an efficient formulation tool to overcome the challenges with current antibiotics therapy and resistance. A series of pH-responsive lipid molecules were designed and synthesized for future liposomal formulation as a nano-drug delivery system for vancomycin at the infection site. The structures of these lipids differ from each other in respect of hydrocarbon tails: Lipid1, 2, 3 and 4 have stearic, oleic, linoleic, and linolenic acid hydrocarbon chains, respectively...
March 9, 2017: Cell Biochemistry and Biophysics
https://www.readbyqxmd.com/read/28263181/the-cancer-warburg-effect-may-be-a-testable-example-of-the-minimum-entropy-production-rate-principle
#13
Bartolome Sabater, Dolores Marin
Cancer cells consume more glucose by glycolytic fermentation to lactate than by respiration, a characteristic known as the Warburg effect. In contrast with the 34 moles of ATP produced by respiration, fermentation produces two moles of ATP per mole of glucose consumed, which poses a puzzle on the function of the Warburg effect. Productions of free energy (ΔG), enthalpy (ΔH) and entropy (ΔS) per mole linearly vary with the fraction (x) of glucose consumed by fermentation that is frequently estimated around 0...
March 6, 2017: Physical Biology
https://www.readbyqxmd.com/read/28262903/an-efficient-route-to-fabricate-fatigue-free-p-vdf-trfe-capacitors-with-enhanced-piezoelectric-and-ferroelectric-properties-and-excellent-thermal-stability-for-sensing-and-memory-applications
#14
Deepa Singh, Deepak, Ashish Garg
P(VDF-TrFE), the best known ferroelectric polymer, suffers from a rather low piezoelectric response as well as poor electrical fatigue life, hampering its application potential. Herein, we report the fabrication of fatigue free poly(vinylidenedifluoride-trifluoroethylene) P(VDF-TrFE)-based capacitors with record piezoelectric coefficients and excellent thermal stability. We proposed a cost-effective and simple solution-based process to fabricate P(VDF-TrFE)-based memory capacitors with large polarization (8...
March 6, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28255231/insight-into-resistance-mechanisms-of-azd4547-and-e3810-to-fgfr1-gatekeeper-mutation-via-theoretical-study
#15
Donglou Liang, Qiaowan Chen, Yujin Guo, Ting Zhang, Wentao Guo
Inhibitors targeting the amplification of the fibroblast growth factor receptor 1 (FGFR1) have found success in the treatment of FGFR1-positive squamous cell lung and breast cancers. A secondary mutation of gatekeeper residue (V561M) in the binding site has been linked to the acquired resistance. Recently, two well-known small molecule inhibitors of FGFR1, AZD4547 and E3810, reported that the V561M mutation confers significant resistance to E3810, while retaining affinity for AZD4547. FGFR1 is widely investigated as potential therapeutic target, while there are few computational studies made to understand the resistance mechanisms about FGFR1 V561M gatekeeper mutation...
2017: Drug Design, Development and Therapy
https://www.readbyqxmd.com/read/28247939/double-mutants-in-dna-gyrase-lead-to-ofloxacin-resistance-in-mycobacterium-tuberculosis
#16
Bharati Pandey, Sonam Grover, Chetna Tyagi, Sukriti Goyal, Salma Jamal, Aditi Singh, Jagdeep Kaur, Abhinav Grover
Fluoroquinolones are among the most important classes of highly effective antibacterial drugs, exhibiting wide range of activity to cure infectious diseases. Ofloxacin is second generation fluoroquinolone approved by FDA for the treatment of tuberculosis by selectively inhibiting DNA gyrase. However, the emergence of drug resistance owing to mutations in DNA gyrase poses intimidating challenge for the effective therapy of this drug. The double mutants GyrA(A90V) GyrB(D500N) and GyrA(A90V) GyrB(T539N) arereported to be implicated in conferring higher levels of OFX resistance...
March 1, 2017: Journal of Cellular Biochemistry
https://www.readbyqxmd.com/read/28213147/unusual-energy-properties-of-leaky-backward-lamb-waves-in-a-submerged-plate
#17
I A Nedospasov, V G Mozhaev, I E Kuznetsova
It is found that leaky backward Lamb waves, i.e. waves with negative energy-flux velocity, propagating in a plate submerged in a liquid possess extraordinary energy properties distinguishing them from any other type of waves in isotropic media. Namely, the total time-averaged energy flux along the waveguide axis is equal to zero for these waves due to opposite directions of the longitudinal energy fluxes in the adjacent media. This property gives rise to the fundamental question of how to define and calculate correctly the energy velocity in such an unusual case...
February 1, 2017: Ultrasonics
https://www.readbyqxmd.com/read/28211690/understanding-the-cubic-phase-stabilization-and-crystallization-kinetics-in-mixed-cations-and-halides-perovskite-single-crystals
#18
Li-Qiang Xie, Liang Chen, Zi-Ang Nan, Hai-Xin Lin, Tan Wang, Dong-Ping Zhan, Jia-Wei Yan, Bing-Wei Mao, Zhong-Qun Tian
The spontaneous α-to-δ phase transition of the formamidinium-based (FA) lead halide perovskite hinders its large scale application in solar cells. Though this phase transition can be inhibited by alloying with methylammonium-based (MA) perovskite, the underlying mechanism is largely unexplored. In this Communication, we grow high-quality mixed cations and halides perovskite single crystals (FAPbI3)1-x(MAPbBr3)x to understand the principles for maintaining pure perovskite phase, which is essential to device optimization...
February 23, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28196892/modeling-the-two-way-feedback-between-contractility-and-matrix-realignment-reveals-a-nonlinear-mode-of-cancer-cell-invasion
#19
Hossein Ahmadzadeh, Marie R Webster, Reeti Behera, Angela M Jimenez Valencia, Denis Wirtz, Ashani T Weeraratna, Vivek B Shenoy
Cancer cell invasion from primary tumors is mediated by a complex interplay between cellular adhesions, actomyosin-driven contractility, and the physical characteristics of the extracellular matrix (ECM). Here, we incorporate a mechanochemical free-energy-based approach to elucidate how the two-way feedback loop between cell contractility (induced by the activity of chemomechanical interactions such as Ca(2+) and Rho signaling pathways) and matrix fiber realignment and strain stiffening enables the cells to polarize and develop contractile forces to break free from the tumor spheroids and invade into the ECM...
February 28, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28190683/there-and-back-again-two-views-on-the-protein-folding-puzzle
#20
REVIEW
Alexei V Finkelstein, Azat J Badretdin, Oxana V Galzitskaya, Dmitry N Ivankov, Natalya S Bogatyreva, Sergiy O Garbuzynskiy
The ability of protein chains to spontaneously form their spatial structures is a long-standing puzzle in molecular biology. Experimentally measured folding times of single-domain globular proteins range from microseconds to hours: the difference (10-11 orders of magnitude) is the same as that between the life span of a mosquito and the age of the universe. This review describes physical theories of rates of overcoming the free-energy barrier separating the natively folded (N) and unfolded (U) states of protein chains in both directions: "U-to-N" and "N-to-U"...
January 27, 2017: Physics of Life Reviews
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