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Complexity theory

Ines Starke, Andreas Koch, Stefan Kammer, Hans-Jürgen Holdt, Heiko Michael Möller
The complex formation of the following diazaperylene ligands (L) 1,12-diazaperylene 1, 1,1'-bisisoquinoline 2, 2,11-disubstituted 1,12-diazaperylenes (alkyl=methyl, ethyl, isopropyl, 3, 5, 7), 3,3'-disubstituted 1,1'-bisisoquinoline (alkyl=methyl, ethyl, isopropyl), 4, 6, 8 and with R = phenyl, 11 and with pyridine 12) and the 5,8-dimethoxy-substituted diazaperylene 9, 6,6'- dimethoxy-substituted bisisoquinoline 10 with AgBF4 was investigated. Collision-induced dissociation measurements were used to evaluate the relative stabilities of the ligands themselves and for the [1:1] + complexes as well as for the homoleptic and heteroleptic silver [1:2] + complexes in the gas phase...
February 16, 2018: Journal of Mass Spectrometry: JMS
Ahsan Sethi, Susie Schofield, Sean McAleer, Rola Ajjawi
Demand for postgraduate qualifications in medical education can be judged by the increase in providers worldwide over the last two decades. However, research into the impact of such courses on identity formation of healthcare professionals is limited. This study investigates the influence of such programmes on graduates' educational identities, practices and career progression. Informed by constructivist grounded theory (CGT), semi-structured interviews were conducted with 27 graduates (2008-2012) from one postgraduate programme, who were at different stages in their careers worldwide...
February 16, 2018: Advances in Health Sciences Education: Theory and Practice
Qiaoping Kong, Haizhen Wu, Lei Liu, Fengzhen Zhang, Sergei Preis, Shuang Zhu, Chaohai Wei
Polycyclic aromatic hydrocarbons (PAHs) are accumulated in the sludge collected from the coking wastewater treatment. Phenol with its efficient degradation observed in biological treatment promotes the solubility of PAHs in aqueous phase. The interaction mechanism of phenol and PAHs in aqueous and sludge phases was systematically studied in two full-scale engineering projects composed of anaerobic-oxic-oxic (A-O 1 -O 2 ) and anaerobic-oxic-hydrolytic-oxic (A-O 1 -H-O 2 ) sequences. The results showed that reasonable use of phenol facilitates solubilization of PAHs alleviating their emission problems...
February 13, 2018: Science of the Total Environment
Carlos D S Silva, Iury A Paz, Felipe D Abreu, Aurideia P de Sousa, Carla P Veríssimo, Nilberto R F Nascimento, Tércio F Paulo, Davila Zampieri, Marcos N Eberlin, Ana C S Gondim, Loraine C Andrade, Idalina M M Carvalho, Eduardo H S Sousa, Luiz G F Lopes
Nitric oxide has been involved in many key biological processes such as vasodilation, platelet aggregation, apoptosis, memory function, and this has drawn attention to the development of exogenous NO donors. Metallonitrosyl complexes are an important class of these compounds. Here, two new ruthenium nitrosyl complexes containing a thiocarbonyl ligand, with the formula cis-[Ru(phen) 2 (L)(NO)](PF 6 ) 3 (phen = phenantroline, L = thiourea or thiobenzamide), were synthesized and characterized by electronic spectroscopy, FTIR, NMR , mass spectrometry and voltammetric techniques...
February 9, 2018: Journal of Inorganic Biochemistry
Christina Villard, Rebecka Hultgren
OBJECTIVE: Abdominal aortic aneurysm (AAA) predominantly affects an elderly male population. Even so, AAA appears more detrimental in women, who experience a higher risk of aneurysm rupture and a worse outcome after surgery than men. Why women are privileged from yet are worse off once affected has been attributed to an effect of sex hormones. This review summarizes the knowledge of sex differences in AAA and addresses the changes in the aneurysm wall from a gender perspective. METHOD: Standard reporting guidelines set by the PRISMA Group were followed to identify studies examining AAA from a gender perspective...
March 2018: Maturitas
Jiří Chmela, Jean-Francois Greisch, Michael E Harding, Wim Klopper, Manfred M Kappes, Detlef Schooss
The gas-phase laser-induced photoluminescence of cationic mononuclear gadolinium and lutetium complexes involving two 9-oxo-phenalen-1-one ligands is reported. Performing measurements at a temperature of 83 K enables to resolve vibronic transitions. Via comparison to Franck-Condon computations, the main vibrational contributions to the ligand-centered phosphorescence are determined to involve rocking, wagging, and stretching of the 9-oxophenalen-1-one-lanthanoid coordination in the low energy range, intraligand bending and stretching in the medium to high energy range, rocking of the carbonyl and methine groups, as well as C-H stretching beyond...
February 16, 2018: Journal of Physical Chemistry. A
Shubhra Sarkar, Nagarajan Ramanathan, Kalyanasundaram Sundararajan
Hydrogen bonded interactions of pyrrole with water and methanol have been studied using matrix isolation infrared spectroscopy and compared with the calculation performed on dimethyl ether. Computations carried out at MP2/aug-cc-pVDZ level of theory yielded two minima for the pyrrole-water and pyrrole-methanol complexes. The global and local minima correspond to the N-H∙∙∙O and O-H∙∙∙π complexes, respectively, where the N-H group of pyrrole interacts with oxygen of water/methanol and O-H of water and methanol interacts with the π cloud of pyrrole...
February 16, 2018: Journal of Physical Chemistry. A
Anthony K Cheetham, G Kieslich, H H-M Yeung
The evolution of metal-organic frameworks (MOFs) has been one of the most exciting aspects of materials chemistry over the last 20 years. In this Account, we discuss the development during this period in our understanding of the factors that control the crystallization of MOFs from solution. Both classical porous MOFs and dense MOF phases are considered. This is an opportune time at which to examine this complex area because the experimental tools now available to interrogate crystallization processes have matured significantly in the last 5 years, particularly with the use of in situ synchrotron X-ray diffraction...
February 16, 2018: Accounts of Chemical Research
Lisa A Fredin, Thomas C Allison
Computational investigation of the photochemical properties of transition-metal-centered dyes typically involves optimization of the molecular structure followed by calculation of the UV/visible spectrum. At present, these steps are usually carried out using density functional theory (DFT) and time-dependent DFT calculations. Recently, we demonstrated that semiempirical methods with appropriate parameterization could yield geometries that were in very good agreement with DFT calculations, allowing large sets of molecules to be screened quickly and efficiently...
February 15, 2018: Journal of Computational Chemistry
Aditi Chandrasekar, Brahmmananda Rao C V S, Mahesh Sundararajan, Tapan K Ghanty, N Sivaraman
The structural effects of the carbon chain on the extraction of actinides by organo-phosphorus extractants have been examined experimentally and by computation. Branched butyl H-phosphonates and their linear chain isomer, n-butyl H-phosphonate (DBHP), were synthesised and characterised using IR, NMR and GC-MS techniques. Their physical properties viz. viscosity, density and aqueous solubility have been examined. DBHP, Di-iso-butyl H phosphonate (DiBHP) and Di-sec-butyl H phosphonate (DsBHP) were employed for the extraction of uranium and americium ions from nitric acid...
February 16, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
Bo-Bo Wei
Universality classes of non-unitary critical theories in two-dimensions are characterized by the central charge. However, experimental determination of the central charge of a non-unitary critical theory has not been done before because of the intrinsic difficulty that complex parameters usually occur in non-unitary theory, which is not physical. Here we propose to extract the effective central charge of the non-unitary critical point of a two-dimensional lattice model from the quantum coherence measurement of a probe spin which is coupled to the lattice model...
February 15, 2018: Scientific Reports
Duc Nguyen, Joshua J Goings, Huy A Nguyen, Joseph Lyding, Xiaosong Li, Martin Gruebele
We previously demonstrated that we can image electronic excitations of quantum dots by single-molecule absorption scanning tunneling microscopy (SMA-STM). With this technique, a modulated laser beam periodically saturates an electronic transition of a single nanoparticle, and the resulting tunneling current modulation ΔI(x 0 , y 0 ) maps out the SMA-STM image. In this paper, we first derive the basic theory to calculate ΔI(x 0 , y 0 ) in the one-electron approximation. For near-resonant tunneling through an empty orbital "i" of the nanostructure, the SMA-STM signal is approximately proportional to the electron density φ i x 0 ,y 0 2 of the excited orbital in the tunneling region...
February 14, 2018: Journal of Chemical Physics
Mike Reppert, Paul Brumer
Two-dimensional (2D) ultrafast spectroscopy is a powerful tool for studying the electronic and vibrational structures of complex systems. Unfortunately, the physical interpretation of these experiments is obscured by conceptual problems in classical response theory, i.e., the divergence of classical nonlinear response functions. We demonstrate that these difficulties are avoided by modeling classical 2D experiments nonperturbatively, illustrating that nonlinear spectroscopy and nonlinear response are not synonymous...
February 14, 2018: Journal of Chemical Physics
Diego Camargo, J A de la Torre, D Duque-Zumajo, Pep Español, Rafael Delgado-Buscalioni, Farid Chejne
Density Functional Theory (DFT) is a successful and well-established theory for the study of the structure of simple and complex fluids at equilibrium. The theory has been generalized to dynamical situations when the underlying dynamics is diffusive as in, for example, colloidal systems. However, there is no such a clear foundation for Dynamic DFT (DDFT) for the case of simple fluids in contact with solid walls. In this work, we derive DDFT for simple fluids by including not only the mass density field but also the momentum density field of the fluid...
February 14, 2018: Journal of Chemical Physics
Qinghui Ge, Yuezhi Mao, Martin Head-Gordon
An energy decomposition analysis (EDA) scheme is developed for understanding the intermolecular interaction involving molecules in their excited states. The EDA utilizes absolutely localized molecular orbitals to define intermediate states and is compatible with excited state methods based on linear response theory such as configuration interaction singles and time-dependent density functional theory. The shift in excitation energy when an excited molecule interacts with the environment is decomposed into frozen, polarization, and charge transfer contributions, and the frozen term can be further separated into Pauli repulsion and electrostatics...
February 14, 2018: Journal of Chemical Physics
Ke Liu, Jonas Greitemann, Lode Pollet
Polyhedral nematics are examples of exotic orientational phases that possess a complex internal symmetry, representing highly nontrivial ways of rotational symmetry breaking, and are subject to current experimental pursuits in colloidal and molecular systems. The classification of these phases has been known for a long time; however, their transitions to the disordered isotropic liquid phase remain largely unexplored, except for a few symmetries. In this work, we utilize a recently introduced non-Abelian gauge theory to explore the nature of the underlying nematic-isotropic transition for all three-dimensional polyhedral nematics...
January 2018: Physical Review. E
Carlos Granero-Belinchón, Stéphane G Roux, Nicolas B Garnier
For generic systems exhibiting power law behaviors, and hence multiscale dependencies, we propose a simple tool to analyze multifractality and intermittency, after noticing that these concepts are directly related to the deformation of a probability density function from Gaussian at large scales to non-Gaussian at smaller scales. Our framework is based on information theory and uses Shannon entropy and Kullback-Leibler divergence. We provide an extensive application to three-dimensional fully developed turbulence, seen here as a paradigmatic complex system where intermittency was historically defined and the concepts of scale invariance and multifractality were extensively studied and benchmarked...
January 2018: Physical Review. E
Tomohiko G Sano, Hirofumi Wada
When a flat elastic strip is compressed along its axis, it is bent in one of two possible directions via spontaneous symmetry breaking, forming a cylindrical arc. This is a phenomenon well known as Euler buckling. When this cylindrical section is pushed in the other direction, the bending direction can suddenly reverse. This instability is called "snap-through buckling" and is one of the elementary shape transitions in a prestressed thin structure. Combining experiments and theory, we study snap-buckling of an elastic strip with one end hinged and the other end clamped...
January 2018: Physical Review. E
Jan Hermann, Alexandre Tkatchenko
Short-range correlations in motion of electrons in matter are captured well by semilocal exchange-correlation (XC) functionals in density functional theory (DFT), but long-range correlations are neglected in such models and must be treated by van der Waals (vdW) dispersion methods.Whereas the effective range of distances at which fluctuations are correlated is usually explicit in the vdW models, the complementary range of semilocal functionals can be observed only implicitly, requiring an introduction of empirical damping functions to couple the semilocal and nonlocal contributions to the XC energy...
February 15, 2018: Journal of Chemical Theory and Computation
Gareth Parry, Astou Coly, Don Goldmann, Alex Rowe, Vijay Chattu, Deneil Logiudice, Mihajlo Rabrenovic, Bejoy Nambiar
A lack of clear guidance for funders, evaluators and improvers on what to include in evaluation proposals can lead to evaluation designs that do not answer the questions stakeholders want to know. These evaluation designs may not match the iterative nature of improvement and may be imposed onto an initiative in a way that is impractical from the perspective of improvers and the communities with whom they work. Consequently, the results of evaluations are often controversial, and attribution remains poorly understood...
February 13, 2018: International Journal for Quality in Health Care
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