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https://www.readbyqxmd.com/read/28532116/antibacterial-mechanical-and-surface-properties-of-ag-dlc-films-prepared-by-dual-pld-for-medical-applications
#1
P Písařík, M Jelínek, J Remsa, J Mikšovský, J Zemek, K Jurek, Š Kubinová, J Lukeš, J Šepitka
Silver doped diamond-like carbon layers were deposited by dual pulsed laser deposition using two KrF excimer lasers. The concentration of Ag, determined by XPS and WDS, moved from zero to ~10at%. We found that the sp(2)/sp(3) ratio, film roughness and the number of droplets (SEM and AFM) increased with increasing silver concentration. The sp(3) content measurement (XPS) was influenced by ion cluster surface sputtering and varied from 71.0% (undoped DLC) to 36.2% (for 9.3at% Ag). Transmission was measured on the scale from 200nm to 1100nm, and decreased with increasing silver content...
August 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
https://www.readbyqxmd.com/read/28531974/biomimetic-collagen-phospholipid-coatings-improve-formation-of-hydroxyapatite-nanoparticles-on-titanium
#2
Gilia C M Ruiz, Marcos A E Cruz, Amanda N Faria, Daniela C Zancanela, Pietro Ciancaglini, Ana P Ramos
Osseointegration between the surface of a certain material and the host tissue helps to evaluate the potential use of biomaterials in bone replacement. The physicochemical properties and biochemical composition of the material's surface regulates osseointegration. This study investigates how collagen into biomimetic matrixes affects hydroxyapatite (HAp) growth. Collagen was inserted into insoluble Langmuir monolayers containing either 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC) or octadecylphosphonic acid (OPA) and transferred to titanium (Ti) supports by means of the Langmuir-Blodgett (LB) technique...
August 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
https://www.readbyqxmd.com/read/28531353/comprehensive-thermodynamic-profiling-for-the-binding-of-a-g-quadruplex-selective-indoloquinoline
#3
Andrea Funke, Klaus Weisz
Binding of a positively charged indoloquinoline derivative to a G-quadruplex formed by the G-rich promoter element of the c-MYC oncogene was subjected to a rigorous isothermal calorimetric analysis. Binding of the indoloquinoline is primarily enthalpy-driven but is also promoted by a favorable entropy term. Both binding enthalpy ΔH° and binding entropy ΔS° exhibit a noticeable temperature dependence with almost complete enthalpy-entropy compensation as a result of a negative change in heat capacity ΔCp°...
May 22, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28530824/human-immune-protein-c1q-selectively-disaggregates-carbon-nanotubes
#4
Maximilien Saint Cricq, Jesús Carrete, Christine Gaboriaud, Edmond Gravel, Eric Doris, Nicole Thielens, Natalio Mingo, Wai Li Ling
We atomistically compute the change in free energy upon binding of the globular domain of the complement protein C1q to carbon nanotubes (CNTs) and graphene in solution. Our modeling results imply that C1q is able to disaggregate and disperse bundles of large diameter multi-walled CNTs but not those of thin single-walled CNTs, and we validate this prediction with experimental observations. The results support the view of a strong binding, with potential implications for the understanding of the immune response and biomedical applications of graphitic nanomaterials...
May 22, 2017: Nano Letters
https://www.readbyqxmd.com/read/28530798/heterogeneous-molecular-catalysis-of-electrochemical-reactions-volcano-plots-and-catalytic-tafel-plots
#5
Cyrille Costentin, Jean-Michel Savéant
We analyze here, in the framework of heterogeneous mo-lecular catalysis the reasons of occurrence or non-occurrence of volcanoes upon plotting the kinetics of the catalytic reaction versus the stabilization free energy of the primary intermediate of the catalytic process. As in the case of homogeneous molecular catalysis or catalysis by surface active metallic sites, a strong motivation of such studies relates to modern energy challenges, particularly those involving small molecules such as water, hydrogen, oxygen, proton and carbon dioxide...
May 22, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28530193/surface-adsorption-of-poisonous-pb-ii-ions-from-water-using-chitosan-functionalised-magnetic-nanoparticles
#6
Femina Carolin Christopher, Saravanan Anbalagan, Ponnusamy Senthil Kumar, Sundar Rajan Pannerselvam, Vinoth Kumar Vaidyanathan
In this study, chitosan functionalised magnetic nano-particles (CMNP) was synthesised and utilised as an effective adsorbent for the removal of Pb(II) ions from aqueous solution. The experimental studies reveal that adsorbent material has finer adsorption capacity for the removal of heavy metal ions. Parameters affecting the adsorption of Pb(II) ions on CMNP, such as initial Pb(II) ion concentration, contact time, solution pH, adsorbent dosage and temperature were studied. The adsorption equilibrium study showed that present adsorption system followed a Freundlich isotherm model...
June 2017: IET Nanobiotechnology
https://www.readbyqxmd.com/read/28530008/field-strength-and-frequency-tunable-two-way-rotation-of-liquid-crystal-micro-particles-dispersed-in-a-liquid-crystal-host
#7
Koki Imamura, Hiroyuki Yoshida, Masanori Ozaki
Liquid crystal (LC) micro-particles are functional materials possessing anisotropies of LCs originating from their inner molecular alignment, and are fabricated by polymerizing pre-aligned rod-like molecules in the LC state. Here we demonstrate field strength and frequency tunable two-way rotation control of LC micro-particles in a LC host, and unravel its mechanism by theoretically calculating the contributing free energies. Cuboid-shaped micro-particles with inner molecular alignment along the long axis are fabricated via two-photon excited direct laser writing, and dispersed in a dual-frequency (DF) LC to be electrically driven by a voltage applied in the in-plane direction of the cell...
May 22, 2017: Soft Matter
https://www.readbyqxmd.com/read/28527450/on-the-accuracy-of-one-and-two-particle-solvation-entropies
#8
Benedict W J Irwin, David J Huggins
Evaluating solvation entropies directly and combining with direct energy calculations is one way of calculating free energies of solvation and is used by Inhomogeneous Fluid Solvation Theory (IFST). The configurational entropy of a fluid is a function of the interatomic correlations and can thus be expressed in terms of correlation functions. The entropies in this work are directly calculated from a truncated series of integrals over these correlation functions. Many studies truncate all terms higher than the solvent-solute correlations...
May 21, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28527449/correlated-matrix-fluctuation-mediated-activated-transport-of-dilute-penetrants-in-glass-forming-liquids-and-suspensions
#9
Rui Zhang, Kenneth S Schweizer
We formulate a microscopic, force-level statistical mechanical theory for the activated diffusion of dilute penetrants in dense liquids, colloidal suspensions, and glasses. The approach explicitly and self-consistently accounts for coupling between penetrant hopping and matrix dynamic displacements that actively facilitate the hopping event. The key new ideas involve two mechanistically (at a stochastic trajectory level) coupled dynamic free energy functions for the matrix and spherical penetrant particles...
May 21, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28527448/estimating-thermodynamic-expectations-and-free-energies-in-expanded-ensemble-simulations-systematic-variance-reduction-through-conditioning
#10
Manuel Athènes, Pierre Terrier
Markov chain Monte Carlo methods are primarily used for sampling from a given probability distribution and estimating multi-dimensional integrals based on the information contained in the generated samples. Whenever it is possible, more accurate estimates are obtained by combining Monte Carlo integration and integration by numerical quadrature along particular coordinates. We show that this variance reduction technique, referred to as conditioning in probability theory, can be advantageously implemented in expanded ensemble simulations...
May 21, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28526839/fluorescence-correlation-spectroscopy-reveals-a-cooperative-unfolding-of-monomeric-amyloid-%C3%AE-42-with-a-low-gibbs-free-energy
#11
Mario Schneider, Stefan Walta, Chris Cadek, Walter Richtering, Dieter Willbold
The amyloid-beta peptide (Aβ) plays a major role in the progression of Alzheimer's disease. Due to its high toxicity, the 42 amino acid long isoform Aβ42 has become of considerable interest. The Aβ42 monomer is prone to aggregation down to the nanomolar range which makes conventional structural methods such as NMR or X-ray crystallography infeasible. Conformational information, however, will be helpful to understand the different aggregation pathways reported in the literature and will allow to identify potential conditions that favour aggregation-incompetent conformations...
May 19, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28525735/structure-based-rational-design-of-self-inhibitory-peptides-to-disrupt-the-intermolecular-interaction-between-the-troponin-subunits-c-and-i-in-neuropathic-pain
#12
Junmin Yu, Shilei Wang, Junjie Yu, Chuansheng Liu, Fenghe Xu, Shijie Wang, Yusheng Yi, Yanwei Yin
The troponin (Tn) is a ternary complex consisting of three subunits TnC, TnI and TnT; molecular disruption of the Tn complex has been recognized as an attractive strategy against neuropathic pain. Here, a self-inhibitory peptide is stripped from the switch region of TnI interaction interface with TnC, which is considered as a lead molecular entity and then used to generate potential peptide disruptors of TnC-TnI interaction based on a rational molecular design protocol. The region is a helical peptide segment capped by N- and C-terminal disorders...
May 3, 2017: Bioorganic Chemistry
https://www.readbyqxmd.com/read/28525653/predicted-philogeny-secondary-conformational-structure-and-epitope-antigenicity-of-immunological-sequences-in-poultry
#13
L J Lara, A P Peconick, É J Fassani, A M P Júnior, P R B Chalfun, D L Raymundo, T A Barçante, J M de P Barçante
Poultry production is faced with different types of stresses that are responsible for issues of animal welfare as well as for economic losses. Moreover, the immunity decreases when animals are stressed. In silico analyses are important in reducing the cost and in increasing the accuracy of scientific results. A bioinformatics tool was used to perform ontology studies on 15 different immunological sequences of poultry. The mRNA structures and sequences with maximum antigenic residues were also predicted. No homology was found between the sequences of poultry and mammals...
May 18, 2017: Genetics and Molecular Research: GMR
https://www.readbyqxmd.com/read/28525359/i36t%C3%A2-t-mutation-in-south-african-subtype-c-c-sa-hiv-1-protease-significantly-alters-protease-drug-interactions
#14
Sibusiso B Maseko, Eden Padayachee, Thavendran Govender, Yasien Sayed, Gert Kruger, Glenn E M Maguire, Johnson Lin
The efficacy of HIV-1 protease inhibition therapies is often compromised by the emergence of mutations in the protease molecule that reduces the binding affinity of inhibitors while maintaining viable catalytic activity and affinity for natural substrates. In the present study, we used a recombinant HIV-1 C-SA protease and a recently reported variant for inhibition (Ki, IC50) and thermodynamic studies against nine clinically used inhibitors. This is the first time that binding free energies for C-SA PR and the mutant are reported...
May 19, 2017: Biological Chemistry
https://www.readbyqxmd.com/read/28524675/experimental-determination-of-dynamical-lee-yang-zeros
#15
Kay Brandner, Ville F Maisi, Jukka P Pekola, Juan P Garrahan, Christian Flindt
Statistical physics provides the concepts and methods to explain the phase behavior of interacting many-body systems. Investigations of Lee-Yang zeros-complex singularities of the free energy in systems of finite size-have led to a unified understanding of equilibrium phase transitions. The ideas of Lee and Yang, however, are not restricted to equilibrium phenomena. Recently, Lee-Yang zeros have been used to characterize nonequilibrium processes such as dynamical phase transitions in quantum systems after a quench or dynamic order-disorder transitions in glasses...
May 5, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28523625/identification-of-a-novel-putative-inhibitor-of-the-plasmodium-falciparum-purine-nucleoside-phosphorylase-exploring-the-purine-salvage-pathway-to-design-new-antimalarial-drugs
#16
Luciano Porto Kagami, Gustavo Machado das Neves, Ricardo Pereira Rodrigues, Vinicius Barreto da Silva, Vera Lucia Eifler-Lima, Daniel Fábio Kawano
Malaria, a tropical parasitic disease caused by Plasmodium spp., continues to place a heavy social burden, with almost 200 million cases and more than 580,000 deaths per year. Plasmodium falciparum purine nucleoside phosphorylase (PfPNP) can be targeted for antimalarial drug design since its inhibition kills malaria parasites both in vitro and in vivo. Although the currently known inhibitors of PfPNP, immucillins, are orally available and of low toxicity to animals and humans, to the best of our knowledge, none of these compounds has entered clinical trials for the treatment of malaria...
May 18, 2017: Molecular Diversity
https://www.readbyqxmd.com/read/28523615/a-facile-route-for-preparation-of-magnetic-biomass-activated-carbon-with-high-performance-for-removal-of-dye-pollutants
#17
Hao Luo, Shengxiao Zhang, Xiaoyan Li, Qiang Xu, Junshen Liu, Zhenhua Wang
A novel and simple method for preparing magnetic biomass activated carbon (BAC) was developed. The BAC was prepared by decomposing fallen leaves, and magnetic nanoparticles were grown in situ on BAC using solvothermal method. The prepared magnetic BAC was characterized with FT-IR, XRD, vibrating sample magnetometer, thermo-gravimetric apparatus, SEM, and high-resolution transmission electron microscope, and results indicate that BAC and magnetic nanoparticles were combined together successfully. To investigate the adsorption ability of the composites, several dyes were selected as sample pollutants, and the sorbent showed high adsorption capacity for the dyes...
May 18, 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/28523598/study-on-the-interaction-of-chromate-with-bovine-serum-albumin-by-spectroscopic-method
#18
Hongguang Cao, Yanli Yi
The interaction between two chromates [sodium chromate (Na2CrO4) and potassium chromate K2CrO4)] and bovine serum albumin (BSA) in physiological buffer (pH 7.4) was investigated by the fluorescence quenching technique. The results of fluorescence titration revealed that two chromates could strongly quench the intrinsic fluorescence of BSA through a static quenching procedure. The apparent binding constants K and number of binding sites n of chromate with BSA were obtained by the fluorescence quenching method...
May 18, 2017: Biometals: An International Journal on the Role of Metal Ions in Biology, Biochemistry, and Medicine
https://www.readbyqxmd.com/read/28521626/experimental-evolution-of-resistance-against-bacillus-thuringiensis-in-the-insect-model-host-galleria-mellonella-results-in-epigenetic-modifications
#19
Krishnendu Mukherjee, Ekaterina Grizanova, Ekaterina Chertkova, Ruediger Lehmann, Ivan Dubovskiy, Andreas Vilcinskas
Epigenetic mechanisms have been proposed to translate environmental stimuli into heritable transgenerational phenotypic variations that can significantly influence natural selection. An intriguing example is exposure to pathogens, which imposes selection for host resistance. To test this hypothesis, we used larvae of the greater wax moth Galleria mellonella as model host to experimentally select for resistance to Bacillus thuringiensis (Bt), the most widely used bacterial agent for the biological control of pest insects...
May 19, 2017: Virulence
https://www.readbyqxmd.com/read/28520421/examining-the-feasibility-of-using-free-energy-perturbation-fep-in-predicting-protein-stability
#20
Melissa Coates Ford, Kerim Babaoglu
The importance of engineering protein stability is well known and has the potential to impact many fields ranging from pharmaceuticals to food sciences. Engineering proteins can be both a time consuming and expensive experimental process. The use of computation is a potential solution to mitigating some of the time and expenses required to engineer a protein. This process has been previously hindered by inaccurate force fields or energy equations and slow computational processors, however improved software and hardware have made this goal much more attainable...
May 18, 2017: Journal of Chemical Information and Modeling
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