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Bounded rationality

Barbara Bassi, Giacomo Dacarro, Pietro Galinetto, Enrico Giulotto, Nicoletta Marchesi, Piersandro Pallavicini, Alessia Pascale, Stefano Perversi, Angelo Taglietti
The last decade came across an increasing demand of theranostic biocompatible nanodevices, possessing the double ability of diagnosis and therapy. In this work, we report the design, synthesis and step-by-step characterization of rationally coated gold nanostars (GNS) for SERS imaging and photothermal therapy (PTT) of HeLa cancer cells. The nanodevice was realized synthesizing GNS with a seed-growth approach, coating them with a controlled mixture of thiols composed of a Raman reporter and a polyethylenglicol with a terminal amino group, and then reacting these amino groups with Folic Acid (FA), in order to impart selectivity towards cancer cells which overexpress folate receptors on their membranes...
March 16, 2018: Nanotechnology
Xue-Jiao Ma, Yin-Juan Zhang, Cheng-Ming Zeng
Sodium dodecyl sulfate (SDS), as an anionic surfactant, can induce protein conformational changes. Recent investigations demonstrated different effects of SDS on protein amyloid aggregation. In the present study, the effect of SDS on amyloid aggregation of bovine serum albumin (BSA) was evaluated. BSA transformed to β-sheet-rich amyloid aggregates upon incubation at pH 7.4 and 65°C, as demonstrated by thioflavin T fluorescence, circular dichroism, and transmission electron microscopy. SDS at submicellar concentrations inhibited BSA amyloid aggregation with IC50 of 47...
January 2018: Biochemistry. Biokhimii︠a︡
Stefan E Payer, Hannah Pollak, Silvia M Glueck, Kurt Faber
The promiscuous regio- and stereoselective hydration of 4-hydroxystyrenes catalyzed by ferulic acid decarboxylase from Enterobacter sp. (FDC_ Es ) depends on bicarbonate bound in the active site, which serves as a proton relay activating a water molecule for nucleophilic attack on a quinone methide electrophile. This "cofactor" is crucial for achieving improved conversions and high stereoselectivities for ( S )-configured benzylic alcohol products. Similar effects were observed with simple aliphatic carboxylic acids as additives...
March 2, 2018: ACS Catalysis
Soung-Hun Roh, Nicholas J Stam, Corey F Hryc, Sergio Couoh-Cardel, Grigore Pintilie, Wah Chiu, Stephan Wilkens
The molecular mechanism of transmembrane proton translocation in rotary motor ATPases is not fully understood. Here, we report the 3.5-Å resolution cryoEM structure of the lipid nanodisc-reconstituted Vo proton channel of the yeast vacuolar H+ -ATPase, captured in a physiologically relevant, autoinhibited state. The resulting atomic model provides structural detail for the amino acids that constitute the proton pathway at the interface of the proteolipid ring and subunit a. Based on the structure and previous mutagenesis studies, we propose the chemical basis of transmembrane proton transport...
March 15, 2018: Molecular Cell
Jun He, Xinchi Feng, Kai Wang, Changxiao Liu, Feng Qiu
BACKGROUND: Quality control of Chinese medicine (CM) is an effective measure to ensure the safety and efficacy of CM in clinical practice, which is also a key factor to restrict the modernization process of CM. Various chemical components exist in CM and the determination of several chemical components is the main approach for quality control of vast majority of CM in the present. However, many components determined lack not only specificity, but also biological activities. This is bound to greatly reduce the actual value of quality standard of CM...
February 28, 2018: Phytomedicine: International Journal of Phytotherapy and Phytopharmacology
Marco Betti, Daniela Catarzi, Flavia Varano, Matteo Falsini, Katia Varani, Fabrizio Vincenzi, Diego Dal Ben, Catia Lambertucci, Vittoria Colotta
A new series of amino-3,5-dicyanopyridines (3-28) as analogues of the adenosine hA2B receptor agonist BAY60-6583 (compound 1) was synthesized. All the compounds that interact with the hA2B adenosine receptor display EC50 values in the range 9-350 nM behaving as partial agonists, with the only exception being the 2-{[4-(4-acetamidophenyl)-6-amino-3,5-dicyanopyridin-2-yl]thio}acetamide (8) which shows a full agonist profile. Moreover, the 2-[(1H-imidazol-2-yl)methylthio)]-6-amino-4-(4-cyclopropylmethoxy-phenyl)pyridine-3,5-dicarbonitrile (15) turns out to be 3-fold more active than 1 although less selective...
March 6, 2018: European Journal of Medicinal Chemistry
Stanislav O Fedechkin, Natasha L George, Jacob T Wolff, Lawrence M Kauvar, Rebecca M DuBois
Respiratory syncytial virus (RSV) is a top cause of severe lower respiratory tract disease and mortality in young children and the elderly. The viral envelope G glycoprotein contributes to pathogenesis through its roles in host cell attachment and modulation of host immunity. Although the G glycoprotein is a target of protective RSV-neutralizing antibodies, its development as a vaccine antigen has been hindered by its heterogeneous glycosylation and sequence variability outside a conserved central domain (CCD)...
March 9, 2018: Science Immunology
Diego Brancaccio, Donatella Diana, Salvatore Di Maro, Francesco Saverio Di Leva, Stefano Tomassi, Roberto Fattorusso, Luigi Russo, Stefania Scala, Anna Maria Trotta, Luigi Portella, Ettore Novellino, Luciana Marinelli, Alfonso Carotenuto
Peptides-binding G protein-coupled receptors play an important role in many pathological and physiological pathways. The assessment of the receptor-bound conformation of a peptidic ligand within a membrane receptor such as a GPCR is of outmost importance for a rational drug design of more potent analogues. In this work, we applied multiple ligand-based NMR methods to study the interaction of peptide heptamers, derived from the C-X-C Motif Chemokine 12 (CXCL12), and the C-X-C Chemokine Receptor Type 4 (CXCR4) on membranes of human T-Leukemia cells (CCRF-CEM cells)...
March 9, 2018: Journal of Medicinal Chemistry
Christoph A Riedl, Michaela Hejl, Matthias H M Klose, Alexander Roller, Michael A Jakupec, Wolfgang Kandioller, Bernhard K Keppler
A series of 11 novel ruthenium(ii) arene complexes [Ru(p-cym)(trzC^N )L]NO3 based on the cycloruthenated 1,2,3-triazole scaffold (trzC^N ) bearing different N- or S-donor leaving groups (L) were prepared. These complexes exhibited strongly diverging pH-dependent stability profiles, but consistently exerted antiproliferative effects in the low micromolar range in three cancer cell lines (A549, SW480, CH1/PA-1). The interaction with biomolecules was correlated to dissociation of the monodentate leaving group...
March 9, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
Yogan Khatri, Ilona K Jóźwik, Michael Ringle, Irina Alexandra Ionescu, Martin Litzenburger, Michael Christopher Hutter, Andy-Mark W H Thunnissen, Rita Bernhardt
The production of regio- and stereoselectively hydroxylated steroids is of high pharmaceutical interest and can be achieved by cytochrome P450-based biocatalysts. CYP260A1 from Sorangium cellulosum strain So ce56 catalyzes hydroxylation of C19 or C21 steroids at the very unique 1-position. However, the conversion of progesterone (PROG) by CYP260A1 is very unselective. In order to improve its selectivity we applied a semi-rational protein engineering approach, resulting in two different, highly regio- and stereoselective mutants by replacing a single serine residue (S276) of the substrate recognition site 5 with an asparagine or isoleucine...
March 6, 2018: ACS Chemical Biology
Hannes Konrad Buchholz, Matthias Stein
Accurate lattice energies of organic crystals are important i.e. for the pharmaceutical industry. Periodic DFT calculations with atom-centered Gaussian basis functions with the Turbomole program are used to calculate lattice energies for several non-covalently bound organic molecular crystals. The accuracy and convergence of results with basis set size and k-space sampling from periodic calculations is evaluated for the two reference molecules benzoic acid and naphthalene. For the X23 benchmark set of small molecular crystals accurate lattice energies are obtained using the PBE-D3 functional...
March 5, 2018: Journal of Computational Chemistry
Alexey Smirnov, Asta Zubrienė, Elena Manakova, Saulius Gražulis, Daumantas Matulis
The structure-thermodynamics correlation analysis was performed for a series of fluorine- and chlorine-substituted benzenesulfonamide inhibitors binding to several human carbonic anhydrase (CA) isoforms. The total of 24 crystal structures of 16 inhibitors bound to isoforms CA I, CA II, CA XII, and CA XIII provided the structural information of selective recognition between a compound and CA isoform. The binding thermodynamics of all structures was determined by the analysis of binding-linked protonation events, yielding the intrinsic parameters, i...
2018: PeerJ
Junhai Ma, Lijian Sun, Shunqi Hou, Xueli Zhan
In this paper, a Cournot-Bertrand duopoly model with market share preference is established. Assume that there is a degree of product difference between the two firms, where one firm takes the price as a decision variable and the other takes the quantity. Both firms are bounded rational, with linear cost functions and demand functions. The stability of the equilibrium points is analyzed, and the effects of some parameters (α, β, d and v1 ) on the model stability are studied. Basins of attraction are investigated and the evolution process is shown with the increase in the output adjustment speed...
February 2018: Chaos
Anna M Duraj-Thatte, Pichet Praveschotinunt, Trevor R Nash, Frederick R Ward, Neel S Joshi
Extracellular appendages play a significant role in mediating communication between bacteria and their host. Curli fibers are a class of bacterial fimbria that is highly amenable to engineering. We demonstrate the use of engineered curli fibers to rationally program interactions between bacteria and components of the mucosal epithelium. Commensal E. coli strains were engineered to produce recombinant curli fibers fused to the trefoil family of human cytokines. Biofilms formed from these strains bound more mucins than those producing wild-type curli fibers, and modulated mucin rheology as well...
February 22, 2018: Scientific Reports
Daria Stypinski, Stephen A McQuarrie, Alexander J B McEwan, Leonard I Wiebe
The objective of this work is to evaluate the potential effect of cardiac stress exercise on the accumulation of [123 I]IAZA, a radiopharmaceutical used to image focal tissue hypoxia, in otherwise normal myocardium in healthy volunteers, and to determine the impact of exercise on [123 I]IAZA pharmacokinetics. The underlying goal is to establish a rational basis and a baseline for studies of focal myocardial hypoxia in cardiac patients using [123 I]IAZA. Three healthy male volunteers ran the 'Bruce' treadmill protocol, a clinically-accepted protocol designed to expose myocardial ischemia in patients...
February 22, 2018: Pharmaceutics
Bryan VanSchouwen, Giuseppe Melacini
Hyperpolarization-activated cyclic-nucleotide-modulated (HCN) ion channels control rhythmicity in neurons and cardiomyocytes. Cyclic AMP (cAMP) modulates HCN activity through the cAMP-induced formation of a tetrameric gating ring spanning the intracellular region (IR) of HCN. Although evidence from confocal patch-clamp fluorometry indicates that the cAMP-dependent gating of HCN occurs through a dimer of dimers, the structural and dynamical basis of cAMP allostery in HCN dimers has so far remained elusive. Thus, here we examine how dimers influence IR structural dynamics, and the role that such structural dynamics play in HCN allostery...
February 20, 2018: Journal of Physical Chemistry. B
Gaia Pasqualetto, Andrea Brancale, Mark T Young
P2X receptors are trimeric eukaryotic ATP-gated cation channels. Extracellular ATP-their physiological ligand-is released as a neurotransmitter and in conditions of cell damage such as inflammation, and substantial evidence implicates P2X receptors in diseases including neuropathic pain, cancer, and arthritis. In 2009, the first P2X crystal structure, Danio rerio P2X4 in the apo - state, was published, and this was followed in 2012 by the ATP-bound structure. These structures transformed our understanding of the conformational changes induced by ATP binding and the mechanism of ligand specificity, and enabled homology modeling of mammalian P2X receptors for ligand docking and rational design of receptor modulators...
2018: Frontiers in Pharmacology
Alan C Gibbs, Ruth Steele, Gaohua Liu, Brett A Tounge, Gaetano T Montelione
Dengue virus poses a significant global health threat as the source of increasingly deleterious dengue fever, dengue hemorrhagic fever, and dengue shock syndrome. As no specific antiviral treatment exists for dengue infection, considerable effort is being applied to discover therapies and drugs for maintenance and prevention of these afflictions. The virus is primarily transmitted by mosquitoes, and infection occurs following viral endocytosis by host cells. Upon entering the cell, viral RNA is translated into a large multisubunit polyprotein which is post-translationally cleaved into mature, structural and nonstructural (NS) proteins...
February 21, 2018: Biochemistry
Christopher R Taylor, Graeme M Day
We present a periodic density functional theory study of the stability of 350 organic cocrystals relative to their pure single-component structures, the largest study of cocrystals yet performed with high-level computational methods. Our calculations demonstrate that cocrystals are on average 8 kJ mol -1 more stable than their constituent single-component structures and are very rarely (<5% of cases) less stable; cocrystallization is almost always a thermodynamically favorable process. We consider the variation in stability between different categories of systems-hydrogen-bonded, halogen-bonded, and weakly bound cocrystals-finding that, contrary to chemical intuition, the presence of hydrogen or halogen bond interactions is not necessarily a good predictor of stability...
February 7, 2018: Crystal Growth & Design
Xiaoling Qiu, Wensheng Jia, Dingtao Peng
In this paper, we prove an approximation theorem for equilibrium problems and provide theoretical support for many algorithms. Simon's bounded rationality is illustrated by an approximation theorem, that is, bounded rationality is approaching full rationality as its ultimate goal. Furthermore, by the methods of set-valued analysis, we obtain the generic uniqueness and generic convergence of the solutions of monotone equilibrium problems in the sense of Baire category. As applications, we investigate the optimization problem, variational inequality problem and saddle point problem as special cases...
2018: Journal of Inequalities and Applications
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