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free-energy principle

Bingcheng Luo, Xiaohui Wang, Enke Tian, Hongzhou Song, Hongxian Wang, Longtu Li
A novel lead-free (1-x) CaTiO3-xBiScO3 linear dielectric ceramic with enhanced energy storage density was fabricated. With the composition of BiScO3 increasing, the dielectric constant of (1-x)CaTiO3-xBiScO3 ceramics firstly increased and then decreased after the composition x>0.1, while the dielectric loss decreased firstly and increased. For the composition x=0.1, the polarization was increased into 12.36 μC/cm2, 4.6 times higher than that of the pure CaTiO3. The energy density of 0.9 CaTiO3-0.1 BiScO3 ceramic was 1...
May 24, 2017: ACS Applied Materials & Interfaces
Kai Lv, Chu-Ting Yang, Jun Han, Sheng Hu, Xiao-Lin Wang
Combining the merits of soft-templating and perchlorate oxidation methods, the first-case investigation of niobium alkylphosphonates has uncovered their unique morphology, backbone composition, thermal behavior and huge potentiality as radioanalytical separation materials. These hierarchically porous solids are random aggregates of densely stacked nanolayers perforated with worm-like holes or vesicular voids, manifesting the massif-, tower-like "polymer brush" elevated up to ∼150nm driven by the minimal surface free energy principle...
May 8, 2017: Journal of Chromatography. A
Xiaoyu Wu, Urko Petralanda, Lu Zheng, Yuan Ren, Rongwei Hu, Sang-Wook Cheong, Sergey Artyukhin, Keji Lai
Domain walls (DWs) in ferroic materials, across which the order parameter abruptly changes its orientation, can host emergent properties that are absent in the bulk domains. Using a broadband (10(6) to 10(10) Hz) scanning impedance microscope, we show that the electrical response of the interlocked antiphase boundaries and ferroelectric DWs in hexagonal rare-earth manganites (h-RMnO3) is dominated by the bound-charge oscillation rather than free-carrier conduction at the DWs. As a measure of the rate of energy dissipation, the effective conductivity of DWs on the (001) surfaces of h-RMnO3 at gigahertz frequencies is drastically higher than that at dc, whereas the effect is absent on surfaces with in-plane polarized domains...
May 2017: Science Advances
Yu-Tsung Lin, Shih-Yang Lin, Yu-Huang Chiu, Ming-Fa Lin
The alkali-adsorbed graphene nanoribbons exhibit the feature-rich electronic and magnetic properties. From the first-principles calculations, there are only few adatom-dominated conduction bands, and the other conduction and valence bands are caused by carbon atoms. A lot of free electrons are revealed in the occupied alkali- and carbon-dependent conduction bands. Energy bands are sensitive to the concentration, distribution and kind of adatom and the edge structure, while the total linear free carrier density only relies on the first one...
May 11, 2017: Scientific Reports
Seishi Shimizu, Nobuyuki Matubayasi
The task of elucidating the mechanism of solubility enhancement using hydrotropes has been hampered by the wide variety of phase behaviour that hydrotropes can exhibit, encompassing near-ideal aqueous solution, self-association, micelle formation, and micro-emulsions. Instead of taking a field guide or encyclopedic approach to classify hydrotropes into different molecular classes, we take a rational approach aiming at constructing a unified theory of hydrotropy based upon the first principles of statistical thermodynamics...
May 11, 2017: Physical Chemistry Chemical Physics: PCCP
Jeffrey Comer, Klaus J Schulten, Christophe Chipot
Computational prediction of membrane permeability to small molecules requires accurate description of both the thermodynamics and kinetics underlying translocation across the lipid bilayer. In this contribution, well-converged, μs-long free-energy calculations are combined with a recently developed subdiffusive kinetics framework to describe the membrane permeation of a homologous series of short-tail alcohols, from methanol to 1-butanol, with unprecedented fidelity to the underlying molecular models. While the free-energy profiles exhibit barriers for passage through the center of the bilayer in all cases, the height of these barriers decreases with the length of the aliphatic chain of the alcohol, in quantitative agreement with experimentally determined differential solvation free energies in water and oil...
May 5, 2017: Journal of Chemical Theory and Computation
Yan Li, Fei Ma
Single-element lateral heterostructures composed of black and blue phosphorene are not only free from lattice mismatch but also exhibit rich physical properties related to the seamlessly stitched interfaces, providing the building blocks for designing atomically thin devices. Using first-principles calculations, we investigate the influence of interface structure, size effect and strain engineering on the electronic structure, effective masses and band alignment of black-blue phosphorene lateral heterostructures...
May 17, 2017: Physical Chemistry Chemical Physics: PCCP
Kai S Exner, Herbert Over
Multielectron processes in electrochemistry require the stabilization of reaction intermediates (RI) at the electrode surface after every elementary reaction step. Accordingly, the bond strengths of these intermediates are important for assessing the catalytic performance of an electrode material. Current understanding of microscopic processes in modern electrocatalysis research is largely driven by theory, mostly based on ab initio thermodynamics considerations, where stable reaction intermediates at the electrode surface are identified, while the actual free energy barriers (or activation barriers) are ignored...
May 2, 2017: Accounts of Chemical Research
Alessandra P da Silva, Natália de F Silva, Eloísa Helena A Andrade, Tais Gratieri, William N Setzer, José Guilherme S Maia, Joyce Kelly R da Silva
The essential oils (EOs) of the aerial parts of Lippia origanoides (LiOr), collected in different localities of the Amazon region, were obtained by hydrodistillation and analyzed by GC and CG-MS. Principle component analysis (PCA) based on chemical composition grouped the oils in four chemotypes rich in mono- and sesquiterpenoids. Group I was characterized by 1,8-cineole and α-terpineol (LiOr-1 and LiOr-4) and group II by thymol (LiOr-2). The oil LiOr-3 showed β-caryophyllene, α-phellandrene and β-phellandrene as predominant and LiOr-5 was rich in (E)-nerolidol and β-caryophyllene...
2017: PloS One
Thomas E Ouldridge, Pieter Rein Ten Wolde
Producing a polymer copy of a polymer template is central to biology, and effective copies must persist after template separation. We show that this separation has three fundamental thermodynamic effects. First, polymer-template interactions do not contribute to overall reaction thermodynamics and hence cannot drive the process. Second, the equilibrium state of the copied polymer is template independent and so additional work is required to provide specificity. Finally, the mixing of copies from distinct templates makes correlations between template and copy sequences unexploitable, combining with copying inaccuracy to reduce the free energy stored in a polymer ensemble...
April 14, 2017: Physical Review Letters
Per Söderlind
Lattice dynamics and elasticity for the high-temperature ε phase (body-centered cubic; bcc) of plutonium is predicted utilizing first-principles electronic structure coupled with a self-consistent phonon method that takes phonon-phonon interaction and strong anharmonicity into account. These predictions establish the first sensible lattice-dynamics and elasticity data on ε-Pu. The atomic forces required for the phonon scheme are highly accurate and derived from the total energies obtained from relativistic and parameter-free density-functional theory...
April 25, 2017: Scientific Reports
Young-Kwang Jung, Ji-Hwan Lee, Aron Walsh, Aloysius Soon
CsSnI3 is a potential lead-free inorganic perovskite for solar energy applications due to its nontoxicity and attractive optoelectronic properties. Despite these advantages, photovoltaic cells using CsSnI3 have not been successful to date, in part due to low stability. We demonstrate how gradual substitution of Rb for Cs influences the structural, thermodynamic, and electronic properties on the basis of first-principles density functional theory calculations. By examining the effect of the Rb:Cs ratio, we reveal a correlation between octahedral distortion and band gap, including spin-orbit coupling...
April 11, 2017: Chemistry of Materials: a Publication of the American Chemical Society
Kerstin Boengler, Maik Kosiol, Manuel Mayr, Rainer Schulz, Susanne Rohrbach
Age is the most important risk factor for most diseases. Mitochondria play a central role in bioenergetics and metabolism. In addition, several lines of evidence indicate the impact of mitochondria in lifespan determination and ageing. The best-known hypothesis to explain ageing is the free radical theory, which proposes that cells, organs, and organisms age because they accumulate reactive oxygen species (ROS) damage over time. Mitochondria play a central role as the principle source of intracellular ROS, which are mainly formed at the level of complex I and III of the respiratory chain...
April 21, 2017: Journal of Cachexia, Sarcopenia and Muscle
Xiaohua Zhou, Erhu Zhang, Minggang Xia, Lei Zhang, Zhiqi Tian, Jianlin Liu, Shengli Zhang
Gaining insight into the relationships between the self-organized cell structures and the properties of biotissues is helpful for revealing the function of biomaterials and its designing principle. However, the traditionally used random foam model neglects several important details of the frameworks of cell clusters resulting in incomplete conclusions. Herein, we use a more complete model, the cell adhesion model, to investigate the mechanical and morphological properties of the two-dimensional (2D) dry cell foams...
April 21, 2017: Physical Chemistry Chemical Physics: PCCP
Sigrid Gibson, Margaret Ashwell, Jenny Arthur, Lindsey Bagley, Alison Lennox, Peter J Rogers, Sara Stanner
AIMS: To contribute evidence and make recommendations to assist in achieving free sugars reduction, with due consideration to the broader picture of weight management and dietary quality. METHODS: An expert workshop in July 2016 addressed options outlined in the Public Health England report 'Sugar reduction: The evidence for action' that related directly to the food industry. Panel members contributed expertise in food technology, public heath nutrition, marketing, communications, psychology and behaviour...
April 1, 2017: Perspectives in Public Health
Robert A Pearlstein, Daniel J J McKay, Viktor Hornak, Callum Dickson, Andrei Golosov, Tyler Harrison, Camilo Velez-Vega, José Duca
Cellular drug targets exist within networked function generating systems whose constituent molecular species undergo dynamic interdependent non-equilibrium state transitions in response to specific perturbations (i.e. inputs). Cellular phenotypic behaviors are manifest through the integrated behaviors of such networks. However, in vitro data are frequently measured and/or interpreted with empirical equilibrium or steady state models (e.g. Hill, Michaelis-Menten, Briggs-Haldane) relevant to isolated target populations...
April 14, 2017: Current Topics in Medicinal Chemistry
Xudong Zheng, Feng Ren, Shunping Zhang, Xiaolei Zhang, Hengyi Wu, Xingang Zhang, Zhuo Xing, Wenjing Qin, Yong Liu, Changzhong Jiang
Surface-enhanced Raman spectroscopy (SERS) is a versatile and powerful spectroscopic technique for substance analysis and detection. So far, the highest detection sensitivities have been realized on noble nanostructure substrates, which, however, are costly, unstable, and non-biocompatible. While semiconductor substrates could in principle be used, existing realizations have either resulted in substrates with low sensitivities or used methods that have poor technical control. Here we report a general and versatile method, based on ion irradiation and vacuum annealing, for fabricating large-scale reduced semiconducting oxide SERS substrates with high sensitivities...
April 17, 2017: ACS Applied Materials & Interfaces
Stefan Ringe, Harald Oberhofer, Karsten Reuter
Implicit solvation calculations based on a Stern-layer corrected size-modified Poisson-Boltzmann (SMPB) model are an effective approach to capture electrolytic effects in first-principles electronic structure calculations. For a given salt solution, they require a range of ion-specific parameters, which describe the size of the dissolved ions as well as thickness and shape of the Stern layer. Out of this defined parameter space, we show that the Stern layer thickness expressed in terms of the solute's electron density and the resulting ionic cavity volume completely determine ion effects on the stability of neutral solutes...
April 7, 2017: Journal of Chemical Physics
Elodie Heyer, Karima Benelhadj, Simon Budzák, Denis Jacquemin, Julien Massue, Gilles Ulrich
Herein, a full investigation of the optical properties and first-principles calculations of a large series of original 2-(2'-hydroxybenzofuran)benzazole (HBBX) dyes is described. The electronic substitution on the π-conjugated core of the fluorophores and the nature of the heteroatom (O, S, N) was varied extensively to assess the necessary parameters to trigger a partial frustration of the excited-state intramolecular proton transfer (ESIPT) process, which results in the emission of both tautomers, that is, enol and keto (E* and K*)...
April 8, 2017: Chemistry: a European Journal
L John Hoffer, Roland N Dickerson, Robert G Martindale, Stephen A McClave, Juan B Ochoa Gautier
The precise value of the normal adult protein requirement has long been debated. For many reasons-one of them being the difficulty of carrying out long-term nutrition experiments in free-living people-uncertainty is likely to persist indefinitely. By contrast, the controlled environment of the intensive care unit and relatively short trajectory of many critical illnesses make it feasible to use hard clinical outcome trials to determine protein requirements for critically ill patients in well-defined clinical situations...
April 2017: Nutrition in Clinical Practice
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