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139 results on '"General Chemistry"'

1. Theoretical study of Li2Ti6O13, Li2Sn6O13 and Li2Zr6O13 as possible cathode in Li-ion batteries

Author: J.R. Fernández-Gamboa, Frederik Tielens, Yohandys A. Zulueta, Faculty of Sciences and Bioengineering Sciences, Chemistry, and General Chemistry
Subjects: Mechanics of Materials, Mechanical Engineering, General Materials Science, Condensed Matter Physics
Abstract: Efficient energy storage devices, such as batteries and capacitors play an important role in the development of renewable energy sources. C2/m space group Li2B6O13 (B = Ti4+, Sn4+, or Zr4+) compounds are expected to be materials with high potential for use as negative electrodes in high-performance batteries. The structural and electronic properties of these materials were studied in this article using density functional theory. The increase of the ionic radius of the B ions in the studied materials expands the unit cell parameters and the Li–Li distance in the channel of the Li2B6O13 (B = Ti4+, Sn4+, or Zr4+) compounds. Electronic structure calculations confirm that all structures present semiconductor characteristics. Li2Sn6O13 presents the best semiconductor properties with a band gap of 1.24 eV. The open cell voltages are found to be 2.20, 2.70 and 1.95 V per Li+/Li intercalation in Li2B6O13 structures, respectively. These predicted properties bring in new evidence to consider of these Li2B6O13 for use asan alternative battery materials.
Published: 2022

2. Trapping of Ag+, Cu2+ and Co2+ by faujasite zeolite Y: a combined experimental, DFT and statistical modeling investigation

Author: Sellaoui, Lotfi, Hessou, Etienne Paul, Badawi, Michael, Netto, Matias Schadeck, Dotto, Guilherme Luiz, Silva, Luis Felipe Oliveira, Tielens, Frederik, Ifthikar, Jerosha, Bonilla-Petriciolet, Adrian, Chen, Zhuqi, Chemistry, and General Chemistry
Subjects: Cationic exchange, Chemistry(all), Faujasite-type zeolite Y, Chemical Engineering(all), Environmental Chemistry, Adsorption, Physical modelling, Industrial and Manufacturing Engineering, DFT simulation
Abstract: This work evaluated the potential of a synthesized faujasite-type zeolite Y as an adsorbent for the removal of relevant heavy metals such as silver (Ag+), copper (Cu2+), and cobalt (Co2+). The adsorption data of Ag+, Cu2+, and Co2+ ions were determined experimentally at pH 6 and temperatures of 298, 308, and 318 K. Two theoretical approaches have been applied based on statistical physics modeling and density functional theory (DFT) to understand and characterize the ion exchanges involved in the removal of all metals. Results showed that this zeolite was more efficient for the adsorption of Ag+ via cation-exchange. Based on the physical modelling, the removal of heavy metals on this zeolite was mono and multi-ionic (simple and multi-interactions), where the ions interacted via one and two adsorption sites. It was also noted that the temperature increment generated more available functional groups of the zeolite, facilitating the access to the smaller cavities and the interactions with the adsorbent. Adsorption energies for removing these metals with tested zeolite were slightly endothermic and were consistent with the typical values reported for ion exchange systems of heavy metals + zeolites. DFT results demonstrated that these cationic exchange energies depend on the nature of precursor salt, but with the same ranking. Both statistical and DFT approaches agreed that exchange Ag+ in zeolite Y was easier than Cu2+ and Co2+. Overall, the application of both theoretical approaches provided a reliable interpretation of the adsorption mechanism.
Published: 2021

3. Trapping of Ag+, Cu2+, and Co2+ by faujasite zeolite Y

Author: Michael Badawi, Adrian Bonilla-Petriciolet, Frederik Tielens, Guilherme Luiz Dotto, Matias Schadeck Netto, Etienne Paul Hessou, Lotfi Sellaoui, Jerosha Ifthikar, Luis F.O. Silva, Zhuqi Chen, Chemistry, and General Chemistry
Subjects: Materials science, Ion exchange, Cationic exchange, Chemistry(all), General Chemical Engineering, Inorganic chemistry, chemistry.chemical_element, General Chemistry, Faujasite, engineering.material, Endothermic process, Industrial and Manufacturing Engineering, Ion, DFT simulation, Adsorption, chemistry, Faujasite-type zeolite Y, engineering, Chemical Engineering(all), Environmental Chemistry, Density functional theory, Physical modelling, Zeolite, Cobalt
Abstract: This work evaluated the potential of a synthesized faujasite-type zeolite Y as an adsorbent for the removal of relevant heavy metals such as silver (Ag+), copper (Cu2+), and cobalt (Co2+). The adsorption data of Ag+, Cu2+, and Co2+ ions were determined experimentally at pH 6 and temperatures of 298, 308, and 318 K. Two theoretical approaches have been applied based on statistical physics modeling and density functional theory (DFT) to understand and characterize the ion exchanges involved in the removal of all metals. Results showed that this zeolite was more efficient for the adsorption of Ag+ via cation-exchange. Based on the physical modelling, the removal of heavy metals on this zeolite was mono and multi-ionic (simple and multi-interactions), where the ions interacted via one and two adsorption sites. It was also noted that the temperature increment generated more available functional groups of the zeolite, facilitating the access to the smaller cavities and the interactions with the adsorbent. Adsorption energies for removing these metals with tested zeolite were slightly endothermic and were consistent with the typical values reported for ion exchange systems of heavy metals + zeolites. DFT results demonstrated that these cationic exchange energies depend on the nature of precursor salt, but with the same ranking. Both statistical and DFT approaches agreed that exchange Ag+ in zeolite Y was easier than Cu2+ and Co2+. Overall, the application of both theoretical approaches provided a reliable interpretation of the adsorption mechanism.
Published: 2021

4. Water-silanol interactions on the amorphous silica surface

Author: Mounir Kassir, Youssef Berro, Michael Badawi, Frederik Tielens, Fouad El Haj Hassan, Chemistry, General Chemistry, Laboratoire de Physique et Chimie Théoriques (LPCT), and Institut de Chimie du CNRS (INC)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Surface (mathematics), Silanol defects, spectroscopy, Materials science, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, chemistry.chemical_compound, symbols.namesake, Materials Chemistry, [CHIM]Chemical Sciences, Physical and Theoretical Chemistry, Dispersion-corrected DFT, Range (particle radiation), Amorphous silica, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Atomic and Molecular Physics, and Optics, 0104 chemical sciences, water interaction, Electronic, Optical and Magnetic Materials, Silanol, chemistry, Chemical physics, symbols, van der Waals force, Deformation (engineering), 0210 nano-technology, Dispersion (chemistry), SCAN
Abstract: Interpreting the interaction between the amorphous silica surface and water is a key step to understand its physicochemical properties. However, due to the flexibility of the structure and the distribution of types and geometries of the silanols one can obtain a broad range of interaction energies, as was already shown in former studies. This time we were able to investigate the distribution of silanols in relation with the calculated interaction energies, and thus designate those different silanols sites. Different dispersion-correction PBE-D (PBE + D2, D3, D3-BJ, TS, TS-HI, MBD, and FI-MBD) and meta-GGA SCAN methods has been used to quantify the interactions between water and defined silanols sites of the surface. All the methods give similar interaction energies, showing equivalent performances of SCAN and PBE-D methods to describe week interactions in our system. Following various routes, we identified a protocol of calculation in order to compute the interaction energies more accurately, taking into consideration the van der Waals (vdW) forces. Once different silanols are correctly described within the calculation level, it is clear that the geometry and environment determine its chemistry. Furthermore, the possible deformation of the silica surface affected by the water interaction is studied. The quantification of the interaction energies is important in order to correctly scale the results and confront with the experiments. With this information in mind, one can think about synthesis techniques that modify the silanols distribution of the silica surface in a way to tune its hydrophobicity and acidity.
Published: 2020

5. Analogies between Density Functional Theory Response Kernels and Derivatives of Thermodynamic State Functions

Author: Paul Geerlings, Frank De Proft, Stijn Fias, Vriendenkring VUB, Quantum Chemistry - Molecular Modelling, Chemistry, General Chemistry, and Faculty of Law and Criminology
Subjects: Response kernels, conceptual dft, Stability-concavity/convexity, Analogy with thermodynamics, Physical and Theoretical Chemistry
Abstract: In view of its use as reactivity theory, Conceptual Density Functional Theory (DFT), introduced by Parret al., has mainly concentrated up to now on theE=E[N,v]functional. However, different ensemble representations can be used involving other variables also, such asρandμ. In this study, these different ensemble representations (E, Ω,F, andR) are briefly reviewed. Particular attention is then given to the corresponding second-order (functional) derivatives, and their analogies with the second-order derivatives of thermodynamic state functionsU,F,H, andG, which are related to each otherviaLegendre transformations, just as the DFT functionals (Nalewajski and Parr, 1982). Starting from an analysis of the convexity/concavity of the DFT functionals, for which explicit proofs are discussed for some cases, the positive/negative definiteness of the associated kernels is derived and a detailed comparison is made with the thermodynamic derivatives. The stability conditions in thermodynamics are similar in structure to the convexity/concavity conditions for the DFT functionals. Thus, the DFT functionals are scrutinized based on the convexity/concavity of their two variables, to yield the possibility of establishing a relationship between the three second-order reactivity descriptors derived from the considered functional. Considering two ensemble representations,FandΩ,Fis eliminated as it has two dependent (extensive) variables,Nandρ. ForΩ, on the other hand, which is concave for both of its intensive variables (μandυ), an inequality is derived from its three second-order (functional) derivatives: the global softness, the local softness, and the softness kernel. Combined with the negative value of the diagonal element of the linear response function, this inequality is shown to be compatible with the Berkowitz-Parr relationship, which relates the functional derivatives ofρwithυ, at constantNandμ. This was recently at stake upon quantifying Kohn’s Nearsightedness of Electronic Matter. The analogy of the resulting inequality and the thermodynamic inequality for theGderivatives is highlighted. Potential research paths for this study are briefly addressed; the analogies between finite-temperature DFT response functions and their thermodynamic counterparts and the quest for analogous relationships, as derived in this paper, for DFT functionals that are analogues of entropy-dimensioned thermodynamic functions such as the Massieu function.
Published: 2018

6. Analogies between Density Functional Theory response Kernels and derivarives of Thermodynamic State Functions'

Author: Geerlings, Paul, De Proft, Frank, Fias, Stijn, Chemistry, General Chemistry, and Quantum Chemistry - Molecular Modelling
Abstract: In view of its use as reactivity theory, Conceptual Density Functional Theory (DFT), introduced by Parr et al., has mainly concentrated up to now on the E=E[N, v] functional. However, different ensemble representations can be used involving other variables also, such as ρ and μ. In this study, these different ensemble representations (E, Ω, F, and R) are briefly reviewed. Particular attention is then given to the corresponding second-order (functional) derivatives, and their analogies with the second-order derivatives of thermodynamic state functions U, F, H, and G, which are related to each other via Legendre transformations, just as the DFT functionals (Nalewajski and Parr, 1982). Starting from an analysis of the convexity/concavity of the DFT functionals, for which explicit proofs are discussed for some cases, the positive/negative definiteness of the associated kernels is derived and a detailed comparison is made with the thermodynamic derivatives. The stability conditions in thermodynamics are similar instructure to the convexity/concavity conditions for the DFT functionals. Thus, the DFT functionals are scrutinized based on the convexity/concavity of their two variables, to yield the possibility of establishing a relationship between the three second-order reactivity descriptors derived from the considered functional. Considering two ensemble representations, F and Ω, F is eliminated as it has two dependent (extensive) variables, N and ρ. For Ω, on the other hand, which is concave for both of its intensive variables (μ and υ), an inequality is derived from its three second-order (functional) derivatives:the global softness, the local softness, and the softness kernel. Combined with the negative value of the diagonal element of the linear response function, this inequality is shown to be compatible with the Berkowitz-Parr relationship, which relates the functional derivatives of ρ with υ, at constant N and μ. This was recently at stake upon quantifying Kohn's Nearsightedness of Electronic Matter. The analogy of the resulting inequality and the thermodynamic inequality for the G derivatives is highlighted. Potential research paths for this study are briefly addressed; the analogies between finite-temperature DFT response functions and their thermodynamic counterparts and the quest for analogous relationships, as derived in this paper, for DFT functionals that are analogues of entropy-dimensioned thermodynamic functions such as the Massieu function.
Published: 2018

7. Rationalizing the formation of binary mixed thiol self-assembled monolayers

Author: Frederik Tielens, Douga Nassoko, Mahamadou Seydou, David Portehault, Clément Sanchez, Corinne Chanéac, Claire Goldmann, Chemistry, General Chemistry, Spectroscopie, Modélisation, Interfaces pour L'Environnement et la Santé (SMiLES), Laboratoire de Chimie de la Matière Condensée de Paris (LCMCP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Collège de France (CdF (institution))-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Collège de France (CdF (institution))-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Bamako (ENSup Bamako), Interfaces, Traitements, Organisation et Dynamique des Systèmes (ITODYS (UMR_7086)), Université Paris Diderot - Paris 7 (UPD7)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Matériaux Hybrides et Nanomatériaux (MHN), Chaire Chimie des matériaux hybrides, Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Collège de France (CdF)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Collège de France (CdF)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)
Subjects: Polymers and Plastics, Nanoparticle, Nanotechnology, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, DFT, Catalysis, Nanomaterials, Biomaterials, Adsorption, Colloid and Surface Chemistry, Monolayer, Materials Chemistry, thiols, Chemistry, Intermolecular force, Self-assembled monolayer, Interaction energy, [CHIM.MATE]Chemical Sciences/Material chemistry, self assembly, 021001 nanoscience & nanotechnology, Nano domains, 0104 chemical sciences, Electronic, Optical and Magnetic Materials, Chemical physics, gold nanoparticles, Self-assembly, 0210 nano-technology
Abstract: International audience; Periodic DFT-D calculations are used to decipher the role of intermolecular forces on the stability of mixed linear thiol self-assembled monolayers (SAMs) on Au(111) and compared with experiment. The interaction energy is rationalized by quantifying its different contributions. The inter-chain interaction energy is shown to be in direct relation with the surface reconstruction and the formation of adatoms. The stability of the mixed SAM systems is predicted by calculations and validated with experiments. In order to describe predictively the segregation of binary thiol mixtures adsorption on Au surfaces a segregation descriptor is defined. This procedure is a promising step forward in the prediction of segregated SAMs leading to future functional nanomaterials, including Janus or patchy nanoparticles for optics, formulation and self-assembled patterns.
Published: 2017

8. Expanding the family of C,N-chelated organotin(IV) pseudohalides: Synthesis and structural characterization

Author: Petr Vlasák, Petr Švec, Frank De Proft, Aleš Růžička, Jan Turek, Zdeňka Růžičková, Chemistry, and General Chemistry
Subjects: Thiocyanate, 010405 organic chemistry, Ligand, Stereochemistry, Organic Chemistry, Substituent, chemistry.chemical_element, Infrared spectroscopy, Nuclear magnetic resonance spectroscopy, 010402 general chemistry, 01 natural sciences, Biochemistry, 0104 chemical sciences, Inorganic Chemistry, chemistry.chemical_compound, Trigonal bipyramidal molecular geometry, Crystallography, chemistry, Octahedral molecular geometry, Materials Chemistry, Physical and Theoretical Chemistry, Tin
Abstract: A set of tri- and diorganotin(IV) pseudohalides bearing the 2-(N,N-dimethylaminomethyl)phenyl-as a C,N-chelating ligand (LCN) has been prepared and structurally characterized. Triorganotin(IV) pseudohalides of the type LCNR2SnX [R = n-Bu, X = NCO (1a), NCS (1b), NCSe (1c), CN (1d); R = Ph, X = NCO (2a), NCS (2b), NCSe (2c), CN (2d)] and (LCN)2(n-Bu)SnX [X = NCO (3a), NCS (3b), NCSe (3c), CN (3d)] are monomeric both in solution and the solid state. The central tin atom in these species is five-coordinated in the solid state with distorted trigonal bipyramidal geometry. Monomeric diorganotin(IV) pseudohalides of the type (LCN)2SnX2 [X = NCO (4a), NCS (4b), NCSe (4c), CN (4d)] contain six-coordinated tin atoms with heavily distorted octahedral geometry both in solution and solid state due to the presence of two LCN units. Finally, we have found that LCN(n-Bu)Sn(NCS)2 (5) is presumably dimeric in CDCl3 and monomeric in THF-d8 or DMSO-d6 solution while it forms infinite linear polymer in the solid state via thiocyanate bridges. According to IR, multinuclear NMR spectroscopy and XRD analysis, it was found that the pseudohalide ligands of the Ndouble bondCdouble bondY type (Y = O, S, Se) are bound via nitrogen while the CN substituent act as a common cyanide ligand (i.e. binds via carbon). DFT calculations were performed for selected compounds (2a, 2b, 2d and 4d) to further support our conclusions about the nature of the Sn-pseudohalide bonds. Compound LCNSnPhI2 (6), which was prepared in the scope of this work as well has a trigonal bipyramidal structure with non-equivalent iodine atoms.
Published: 2016

9. N->As intramolecularly coordinated organoarsenic(III) chalcogenides: Isolation of terminal As-S and As-Se bonds

Author: Jan Vrána, Roman Jambor, Ales Ruzicka, Antonin Lycka, Frank De Proft, Libor Dostál, and General Chemistry
Subjects: chelatin ligands, chalcogenides
Abstract: N-> As intramolecularly coordinated organoarsenic5III) chalcogenides: Isolation of terminal As-S and As-Se bonds.
Published: 2013

10. Chromium sites in zeolite framework: Chromyl or chromium hydroxyl groups?

Author: Tetsuya Shishido, Frank De Proft, Mazharul M. Islam, Gabriella Skara, Stanislaw Dzwigaj, Frederik Tielens, General Chemistry, Chemistry, Laboratoire de Réactivité de Surface (LRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physico-Chimie des Surfaces (LPCS), Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Mulliken Center for Theoretical Chemistry, Rheinische Friedrich-Wilhelms-Universität Bonn, Algemene Chemie, Vrije Universiteit Brussel (VUB), Université libre de Bruxelles (ULB), Department of Molecular Engineering, Kyoto University [Kyoto], and Kyoto University
Subjects: Chromium, inorganic chemicals, Chromium sites in zeolite framework, Inorganic chemistry, Ab initio, chemistry.chemical_element, Protonation, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, Deprotonation, otorhinolaryngologic diseases, Molecule, General Materials Science, Fourier transform infrared spectroscopy, Zeolite, Phase diagram, Periodic DFT, technology, industry, and agriculture, [CHIM.CATA]Chemical Sciences/Catalysis, General Chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 0104 chemical sciences, FT-IR, chemistry, Mechanics of Materials, DR UV-vis, 0210 nano-technology
Abstract: International audience; A combined experimental and ab initio periodic DFT calculation on the structure and stability of different chromium-substituted zeolite models are presented. Experimental investigation by XRD, FT-IR and UV-vis show the presence of chromium in SiBEA zeolite. The favorable chromium sites are characterized by their calculated geometrical parameters, energetics, vibrational frequencies and protonation/deprotonation energies. The theoretical vibrational frequencies are compared with experimental FT-IR measurements. A phase diagram was constructed on the basis of calculated total energies of the optimized structures. Cr(III) is stabilized in the zeolite framework as a tri-coordinated site. Cr sites are predicted to be more acidic than group V containing zeolites. Dehydration of the site leads to the formation of a Cr(VI) containing a Crdouble bond; length as m-dashO group. These results are fully consistent with experimental data and allow the identification of the molecular structure of chromium sites in a zeolite framework.
Published: 2012

11. The linear Response Kernel of Conceptual DFT as a Measure of Electron Delocalisation

Author: Paul Geerlings, Frank De Proft, Nick Sablon, General Chemistry, and Chemistry
Subjects: Physics, The linear Response Kernel of Conceptual DFT, Series (mathematics), General Physics and Astronomy, Hardware_PERFORMANCEANDRELIABILITY, Resonance (particle physics), Measure (mathematics), Interpretation (model theory), Matrix (mathematics), Computational chemistry, Kernel (statistics), Hardware_INTEGRATEDCIRCUITS, Density functional theory, Statistical physics, Physics::Chemical Physics, Physical and Theoretical Chemistry, Perturbation theory, Hardware_REGISTER-TRANSFER-LEVELIMPLEMENTATION
Abstract: This letter is concerned with the calculation and interpretation of the atom-condensed linear response kernel as defined within conceptual density functional theory. An easily applicable and accurate methodology following from second order perturbation theory is used to analyse a series of cyclohexane and benzene derivatives. We show that the variation of the condensed linear response matrix elements with internuclear distance provides a means to differentiate between inductive, resonance and hyperconjugation effects and conclude that this quantity measures the extent of electron delocalisation.
Published: 2010

12. Comparative Characterization of two-electron wave functions using Information Theory Measures

Author: Howard, Iris, Borgoo, Alex, Geerlings, Paul, Sen, K.d., Physics, General Chemistry, and Chemistry
Subjects: wavefunctions
Abstract: Comparative Characterization of two-electron wave functions using Information Theory Measures
Published: 2009

13. Nucleophilicity and Electrophilicity of Silylenes from a Molecular Electrostatic Potential and Dual Descriptor Perspectives

Author: Correa, J.v., Jaque Olmedo Pablo, Cesar, Oláh, J., Toro-Labbé, Alejando, Geerlings, Paul, General Chemistry, and Chemistry
Subjects: Nucleophilicity and Electrophilicity of Silylenes
Abstract: Nucleophilicity and Electrophilicity of Silylenes from a Molecular Electrostatic Potential and Dual Descriptor Perspectives
Published: 2009

14. Electron density and Fisher information of Dirac-Fock atoms

Author: Borgoo, Alex, Geerlings, Paul, Sen, K.d., General Chemistry, and Physics
Subjects: Dirac-Fock atoms
Abstract: Numerical calculations on the gradient and Laplacian forms of the position space Fisher information measure are reported using the 1-normalised Dirac–Fock densities (shape function), σ(r), for atoms H–Lr. It is shown that the difference in effective electrostatic potentials, corresponding to the gradient and the Laplacian form of Fishers' information, is completely defined by the shape function (the density per particle) at the nucleus, σ(r=0). The influence of relativistic effects on the Fisher information is recovered for the first time.
Published: 2008

15. Preface (Special Issue – Proceedings CCP 2007 Brussels)

Author: Mareschal, M., Geerlings, Paul, and General Chemistry
Subjects: CCP2007
Abstract: preface
Published: 2008

16. Characterization of the Chandrasekhar correlated two-electron wavefunction using Fisher, Shannon and statistical complexity information measures

Author: Alex Borgoo, Paul Geerlings, K. D. Sen, I. A. Howard, Chemistry, General Chemistry, and Physics
Subjects: Physics, Hartree–Fock method, General Physics and Astronomy, Statistical model, Elementary particle, Information theory, chandrasekhar, symbols.namesake, Quantum mechanics, symbols, Entropy (information theory), Astrophysics::Solar and Stellar Astrophysics, Statistical physics, Fisher information, Wave function, Chandrasekhar limit
Abstract: The three-parameter two-electron correlated analytic wavefunction of Chandrasekhar, parametrized using three physically meaningful conditions on the electron density, is assessed using several information theory measures, the Fisher information, Shannon entropy, and statistical complexity, and compared to the results for the same measures using hydrogenic and Hartree-Fock (HF) orbitals.
Published: 2008

17. Complexity of Dirac Fock atom increases with atomic number

Author: Alex Borgoo, Frank De Proft, Paul Geerlings, Sen, K. D., General Chemistry, and Physics
Subjects: Dirac Fock
Abstract: university of hyderabad
Published: 2007

18. Molecular Oxygen Adsorption on Electropositive Nano Gold Tips

Author: T. Visart de Bocarmé, Norbert Kruse, Thoi-Dai Chau, Frederik Tielens, Juan Andrés, Paul Geerlings, General Chemistry, Chemistry, and Vrije Universiteit Brussel
Subjects: Chemistry, Analytical chemistry, General Physics and Astronomy, Bond-dissociation energy, Dissociation (chemistry), law.invention, Adsorption, law, Colloidal gold, Electric field, Nano, Physical and Theoretical Chemistry, Electron microscope, Field ion microscope
Abstract: The effect of atom coordination and influence of an external electrostatic field on binding and dissociation energies of molecular oxygen on a nano modified Au surfaces are investigated. Weak O and O 2 adsorption are found in our models. A considerable decrease of the dissociation energy of O 2 was found when adsorbed on small gold clusters or gold pyramids. It is concluded that in the presence of an electric field no dissociation of O 2 will occur in our model. This result is in agreement with field ion microscopy (FIM) and field electron microscopy (FEM) experiments, where no dissociation of O 2 is encountered.
Published: 2006

19. Density Functional Study on the Conformation and Energetics of Silanol and Disiloxane

Author: Paul Geerlings, F. De Proft, Frederik Tielens, General Chemistry, Chemistry, Vrije Universiteit Brussel, and Vrije Universiteit Brussel (VUB)
Subjects: 02 engineering and technology, [CHIM.MATE]Chemical Sciences/Material chemistry, Staggered conformation, Disiloxane, 010402 general chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, Biochemistry, 0104 chemical sciences, Hybrid functional, Silanol, chemistry.chemical_compound, Deprotonation, chemistry, Computational chemistry, Physical chemistry, Density functional theory, Physical and Theoretical Chemistry, 0210 nano-technology, Conformational isomerism, Basis set
Abstract: International audience; Six different exchange-correlation functionals were assessed in a quantum chemical study of the geometry and energetics of silanol, its conjugated base and both conformers of disiloxane, using Dunning's augmented correlation consistent basis set. It was found that the B3LYP and the B3PW91 hybrid functionals perform the best, their performance was comparable with MP2/VQZ calculations. A deprotonation energy of -365.4 kcal/mol for silanol was obtained at the B3PWB1/AVQZ level. For disiloxane, a very small difference between both disiloxane conformers, 0.037 kcal/mol (extra stabilization for the doubly staggered conformation) and 149.3 degrees for the very sensible Si-O-Si angle was found, or 154.7 degrees temperature corrected (300 K). degrees 2001 Elsevier Science B.V. All rights reserved.
Published: 2001

20. Performance and basis set dependence of density functional theory dipole and quadrupole moments

Author: Frederik Tielens, Paul Geerlings, F. De Proft, Faculty of Sciences and Bioengineering Sciences, Chemistry, General Chemistry, and Vrije Universiteit Brussel (VUB)
Subjects: 010304 chemical physics, Condensed matter physics, Basis (linear algebra), Chemistry, Basis set dependence, Ab initio, Dipole and quadrupole moments, [CHIM.MATE]Chemical Sciences/Material chemistry, 010402 general chemistry, Condensed Matter Physics, 01 natural sciences, Biochemistry, 0104 chemical sciences, Hybrid functional, Dipole, Quantum mechanics, 0103 physical sciences, Quadrupole, Density functional theory, Molecular orbital, Physical and Theoretical Chemistry, Basis set, density functional theory
Abstract: 5th World Congress of Theoretically Oriented Chemists (WATOC), IMPERIAL COLL, LONDON, ENGLAND, AUG 01-06, 1999; International audience; A study is presented concerning the performance and basis set dependence of density functional methods in the calculation of dipole and quadrupole moments. A set of some small molecules was thereby used, together with seven commonly used exchange correlation functionals and Dunnings correlation consistent aug-cc-pVDZ, aug-cc-pVTZ, aug-cc-pVQZ and aug-cc-pV5Z basis sets. The results were compared with experiment and previously published values obtained with traditional ab initio molecular orbital methods. The best performance in the calculation of dipole and quadrupole moments is due to the hybrid functionals B3LYP and B3PW91. Moreover, the results seem to be essentially converged at the aug-cc-pVTZ level. Comparison of the LDA/aug-cc-pV5Z results with the numerical LDA results of Dickson and Becke, reveals that both sets of values are identical for most cases. (C) 2000 Elsevier Science B.V. All rights reserved.
Published: 2000

21. Molecular Electrostatic Potentials vs. DFT descriptors of reactivity

Author: A. Baeten, Paul Geerlings, Wilfried Langenaeker, F. De Proft, General Chemistry, and Vrije Universiteit Brussel
Subjects: Nucleophile, Computational chemistry, Hydrogen bond, Chemical physics, Chemistry, Intermolecular force, Ab initio, Density functional theory, Interaction energy, Ground state, Wave function
Abstract: The Molecular Electrostatic Potential (MEP) is a reactivity descriptor that occupies an intermediate position: one reaction partner is considered explicitly, the second one being mimicked by a unit test charge, their interaction energy being evaluated without polarization or nuclear rearrangement effects. This approach quickly turned out quite successful for the study of electrophilic reactions, hydrogen bonding and, although not as straightforward as for an electrophilic attack, was later on modified to incorporate the case of nucleophilic reaction. All the above mentioned quantities are obtainable from the wave function of the system that is calculated at semi empirical, ab initio self-consistent field (SCF) or beyond SCF level. The density functional theory (DFT) considers the electron density function, ρ( r ), as the carrier of all information on the molecular ground state. In principle, it thereby avoids the computation of the 4N-variable wave function (N being the number of electrons) and its reduction by integration to a three variable function p( r ). The chapter presents the study on the intra- and intermolecular reactivity sequences of monosubstituted benzenes as a guideline for their relative merits.
Published: 1996

22. Mechanism study of Dual-Emission ratiometric fluorescent pH-Sensitive carbon quantum dots and its application on mornitoring enzymatic catalysis.

Author: Xue Z, Ning, Jia K, Liu H, Xiang Y, Cao J, Chen J, Zhong Y, Wang X, and Zhang Z
Abstract: Carbon dots (CQD) have received significant attention as a novel ratiometric fluorescent pH nanoprobe, owing to their favorable optical properties and excellent biocompatibility. Despite their appealing features, the precise mechanism behind the pH-sensitive photoluminescence of CQDs remains to be fully understood. This study endeavors to unravel the mechanism underlying the pH-responsive ratiometric fluorescence in dual-emission CQDs, synthesized through a one-step hydrothermal method using o-phenylenediamine and oxalic acid as precursors. The resultant CQDs exhibit inherent dual-emission at wavelengths of 383 nm and 566 nm, with the ratiometric fluorescence response tailored by the ratio of precursors, providing a robust tool for pH sensing across a range of 2 to 6. Detailed characterizations, including chemical, morphological, and optical analyses, alongside theoretical insights from time-dependent density functional theory (TD-DFT), elucidate the mechanism underlying the pH-dependent luminescence, attributed to the electron cloud transmission between amide and adjacent carboxyl groups on the CQD surface. The superior performance of these CQDs in real-time pH monitoring is demonstrated through their application in glucose oxidase-catalyzed reactions, showcasing their potential as efficient, reliable nanoprobes for biomedical research and diagnostic applications., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)
Published: 2024
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23. Efficient adsorption of cationic dyes by a novel honeycomb-like porous hydrogel with ultrahigh mechanical property.

Author: Wang Y, Fang LP, Zhang HY, Ren JJ, Liang T, Lv XB, Cheng CJ, and Yu HR
Abstract: The optimization of hydrogel structure is crucial for adsorption capacity, mechanical stability, and reusability. Herein, a chitosan and laponite-XLS co-doped poly(acrylic acid-co-acrylamide) hydrogel (CXAA) with honeycomb-like porous structures is synthesized by cooperative cross-linking of 2-hydroxypropyltrimethyl ammonium chloride chitosan (HACC) and laponite-XLS in reticular frameworks of acrylic acid (AAc) and acrylamide (AM). The CXAA exhibits extraordinary mechanical performances including tough tensile strength (3.36 MPa) and elasticity (2756 %), which facilitates recycling in practical adsorption treatment and broadens potential applications. Since the regular porous structures can fully expose numerous adsorption sites and electronegative natures within polymer materials, CXAA displays efficient and selective adsorption properties for cationic dyes like methylene blue (MB) and malachite green (MG) from mixed pollutants and can reach record-high values (MB = 6886 mg g -1 , MG = 11,381 mg g -1 ) compared with previously reported adsorbents. Therefore, CXAA exhibits promising potential for separating cationic and anionic dyes by their charge disparities. Mechanism studies show that the synergistic effects of HACC, laponite-XLS, and functional groups in monomers promote highly efficient adsorption. Besides, the adsorption capacity of CXAA remains stable even after undergoing five cycles of regeneration. The results confirm that CXAA is a promising adsorbent for effectively removing organic dyes in wastewater., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)
Published: 2024
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24. Bridged triphenylamine-based fluorescent probe for selective and direct detection of HSA in urine.

Author: Deng YD, Liu Q, Wang D, Pan ZW, Du TT, Yuan ZX, and Yi WJ
Subjects: Humans, Molecular Structure, Molecular Docking Simulation, Aniline Compounds chemistry, Aniline Compounds chemical synthesis, Spectrometry, Fluorescence, Fluorescent Dyes chemistry, Fluorescent Dyes chemical synthesis, Serum Albumin, Human urine
Abstract: Human serum albumin (HSA) serves as a crucial indicator for therapeutic monitoring and biomedical diagnosis. In this study, a near infrared (NIR) fluorescent probe, termed BTPA, characterized a donor-π-acceptor (D-π-A) structure based on bridged triphenylamine (TPA) was developed. BTPA exhibited outstanding sensitivity and selectivity towards HSA among various analysts, with a remarkable 50-fold fluorescence enhancement with a significant Stokes shift (∼190 nm) and a wide linear detection range of 0-20 μM of HSA. Especially, BTPA displayed selectivity for discrimination of HSA from BSA. Job's Plot analysis suggested a 1:1 stoichiometry for the formation of the BTPA-HSA complex. Displacement assays and molecular docking demonstrated that BTPA binds to subdomain IB of HSA which could effectively avoid interference from most drugs. Besides, BTPA have good biocompatibility and could detect of exogenous HSA with a relatively low fluorescence background. For practical applications, BTPA was tested for detecting HSA levels in human urine without any pretreatment, showing detection capability in the range of 0-10 μM with a fast response (<30 s), a limit of detection (LOD) of 0.12 μM and good recoveries (81.7-92.9 %), highlighting the high performance of bridged triphenylamine-based probe BTPA., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Inc.)
Published: 2024
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25. Poly-l-lysine modified MOF nanoparticles with pH/ROS sensitive CIP release and CUR triggered photodynamic therapy against drug-resistant bacterial infection.

Author: Xiang YL, Tang DY, Yan LL, Deng LL, Wang XH, Liu XY, and Zhou QH
Subjects: Animals, Mice, Hydrogen-Ion Concentration, Anti-Bacterial Agents pharmacology, Anti-Bacterial Agents chemistry, Drug Liberation, Curcumin pharmacology, Curcumin chemistry, Staphylococcal Infections drug therapy, Polylysine chemistry, Polylysine pharmacology, Photochemotherapy methods, Metal-Organic Frameworks chemistry, Metal-Organic Frameworks pharmacology, Nanoparticles chemistry, Reactive Oxygen Species metabolism, Photosensitizing Agents pharmacology, Photosensitizing Agents chemistry, Methicillin-Resistant Staphylococcus aureus drug effects
Abstract: The challenge of drug resistance in bacteria caused by the over use of biotics is increasing during the therapy process, which has attracted great attentions of the clinicians and scientists around the world. Recently, photodynamic therapy (PDT) triggered by photosensitizer (PS) has become a promising treatment method because of its high efficacy, easy operation, and low side effect. Herein, the poly-l-lysine (PLL) modified metal-organic framework (MOF) nanoparticles, ZIF/PLL-CIP/CUR, were synthesized to allow both reactive oxygen species (ROS) responsive drug release and photodynamic effect for synergistic therapy against drug resistant bacterial infections. The PLL was modified on the shell of the zeolite imidazole framework (ZIF) by the ROS-responsive thioketal linker for controllable CIP release. CUR were encapsulated in ZIF as the photosensitizer for blue light mediated photodynamic effect to produce singlet oxygen ( 1 O 2 ) and superoxide anion radical (O 2 - ) for efficient inhibition towards methicillin-resistant Staphylococcus aureus (MRSA). The charge conversion from negative charge (-4.6 mV) to positive charge (2.6 mV) was observed at pH 7.4 and pH 5.5, and 70.9 % CIP was found released at pH 5.5 in the presence of H 2 O 2 , which suggests the good biosafety at physiological pH and ROS-responsive drug release of the as-prepared nanoparticle in the bacterial microenvironment. The as-prepared nanoparticles could effectively kill MRSA and disrupt bacterial biofilm by combination of chemo- and photodynamic therapy. In mice model, the as-prepared nanoparticles exhibited excellent biosafety and synergistic effect with 98.81 % healing rate in treatment of MRSA infection, which is considered as a promising candidate in combating drug resistant bacterial infection., Competing Interests: Declaration of competing interest All authors have read and approved this version of the article, and due care has been taken to ensure the integrity of the work. No part of this manuscript has published or submitted elsewhere. No conflict of interest exits in the submission of this manuscript., (Copyright © 2024 Elsevier B.V. All rights reserved.)
Published: 2024
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26. Indole-3-acetic acid improves periphyton's resistance to ultraviolet-B: From physiological-biochemical properties and bacteria community to livestock-polluted water purification.

Author: Shi T, Lure M, Zhang R, Liu Z, Hu Q, Liu J, Yang S, and Jing L
Subjects: Animals, Ultraviolet Rays, Ecosystem, Livestock metabolism, Indoleacetic Acids pharmacology, Nitrogen metabolism, Bacteria metabolism, Water, Periphyton, Water Purification methods
Abstract: Livestock-polluted water is a pressing water environmental issue in plateau pastoral regions, necessitating the adoption of eco-friendly solutions. Despite periphyton being a promising alternative, its efficacy is limited by the prevalence of intense ultraviolet radiation, particularly ultraviolet-B (UVB), in these regions. Therefore, this study employs molecular tools and small-scale trials to explore the crucial role of indole-3-acetic acid (IAA) in modulating periphyton characteristics and mediating nutrient removal from livestock-polluted water under UVB exposure. The results revealed that IAA augments periphyton's resilience to UVB stress through several pathways, including increasing periphyton's biomass, producing more extracellular polymeric substances (EPS), and enhancing antioxidant enzyme activities and photosynthetic activity of periphyton. Moreover, IAA addition increased periphyton's bacterial diversity, reshaped bacterial community structure, enhanced community stability, and elevated the R 2 value of neutral processes in bacterial assembly from 0.257 to 0.651 under UVB. Practically, an IAA concentration of 50 mg/L was recommended. Small-scale trials confirmed the effectiveness of IAA in assisting UVB-stressed periphyton to remove nitrogen and phosphorus from livestock-polluted water, without the risk of nitrogen accumulation. These findings offer valuable insights into the protection of aquatic ecosystems in plateau pastoral regions based on periphyton property in an eco-friendly manner., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)
Published: 2024
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27. Toxicity of VO 2 micro/nanoparticles to nitrogen-fixing bacterium Azotobacter vinelandii.

Author: Ouyang P, Yang J, Zhong Q, Yuan Y, Gao Y, Wang H, and Yang ST
Subjects: Nitrogen Fixation genetics, Nitrogen metabolism, Azotobacter vinelandii genetics, Azotobacter vinelandii metabolism, Nitrogen-Fixing Bacteria
Abstract: Vanadium dioxide (VO 2 ) has been used in a variety of products due to its outstanding phase transition properties. However, as potential heavy metal contaminants, the environmental hazards and risks of VO 2 should be systematically investigated. Biological nitrogen fixation is one of the most dominant processes in biogeochemical cycle, which is associated with nitrogen-fixing bacteria. In this study, we reported the environmental bio-effects of VO 2 micro/nanoparticles on the nitrogen-fixing bacterium Azotobacter vinelandii. VO 2 at 10 and 30 mg/L caused severe hazards to A. vinelandii, such as cell apoptosis, oxidative damage, physical damage, genotoxicity, and the loss of nitrogen fixation activity. The up-regulated differentially expressed genes of A. vinelandii were related to stress response, and the down-regulated genes were mainly related to energy metabolism. Surprisingly, VO 2 of 10 mg/L decreased the nif gene expression but elevated the vnf gene expression, which enhanced the ability of A. vinelandii to reduce acetylene in anaerobic environment. In addition, under tested conditions, VO 2 nanoparticles exhibited insignificantly higher toxicity than VO 2 microparticles., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)
Published: 2024
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28. Magnetic ion-imprinted polyacrylonitrile-chitosan electro-spun nanofibrous membrane as recyclable adsorbent with selective heavy metal removal and antibacterial fouling in water treatment.

Author: Hu QH, Tang DY, Xiang YL, Chen X, Lin J, and Zhou QH
Subjects: Escherichia coli, Lead, Staphylococcus aureus, Adsorption, Ions, Magnetic Phenomena, Kinetics, Hydrogen-Ion Concentration, Chitosan, Nanofibers, Metals, Heavy, Water Purification, Water Pollutants, Chemical
Abstract: Water pollution has become one of the most concerned environmental issues on the worldwide scale. Due to the harmfulness of the heavy metal ions and microorganisms in wastewater, novel filtration membranes for water treatment are expected to simultaneously clear these pollutants. Herein, the electro-spun polyacrylonitrile (PAN) based magnetic ion-imprinted membrane (MIIM) were fabricated to achieve both selective removal of Pb(II) ions and excellent antibacterial efficiency. The competitive removal experiments showed that the MIIM displayed efficiently selective removal of Pb(II) (45.4 mg·g -1 ). Pseudo-second-order mode and Langmuir isotherm equation is well matched with the equilibrium adsorption. The MIIM showed sustained removal performance (~79.0 %) against Pb(II) ions after 7 adsorption-desorption cycles with negligible Fe ions loss of 7.3 %. Moreover, the MIIM exhibited excellent antibacterial properties that >90 % of E. coli and S. aureus were killed by the MIIM. In conclusion, the MIIM provides a novel technological platform for integration of multi-function with selective metal ions removal, excellent cycling reusability, and enhanced antibacterial fouling property, which can be potentially utilized as a promising adsorbent in actual treatment of polluted water., Competing Interests: Declaration of competing interest All authors have read and approved this version of the article, and due care has been taken to ensure the integrity of the work. No part of this manuscript has published or submitted elsewhere. No conflict of interest exits in the submission of this manuscript., (Copyright © 2023. Published by Elsevier B.V.)
Published: 2023
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29. Particulate toxicity of metal-organic framework UiO-66 to white rot fungus Phanerochaete chrysosporium.

Author: Yuan H, Li J, Pan L, Li X, Yuan Y, Zhong Q, Wu X, Luo J, and Yang ST
Subjects: Hydrogen Peroxide, Dust, Metal-Organic Frameworks, Phanerochaete, Phthalic Acids
Abstract: Metal-organic frameworks (MOF) are emerging materials with fantastic properties and wide applications. The release of metal ions from MOF materials is usually regarded as the origin of soluble MOF toxicity. However, whether the stable MOF particulates would induce environmental hazards is not clear. Herein, we aimed to reveal the particulate toxicity of MOF materials using the insoluble UiO-66 as the representative MOF and Phanerochaete chrysosporium as the model microorganism. UiO-66 nanoparticles (NPs) were synthesized by solvothermal method and their diameter was 68.4 ± 8.5 nm. UiO-66 NPs were stable in the culture system and the dissolution rate of 500 mg/L group was 0.26% after 14 d incubation. UiO-66 NPs did not affect the fungus growth according to the fresh weight increases and unchanged dry weights. Fungus mycelia kept even at concentrations up to 500 mg/L. Ultrastructural observation showed that UiO-66 NPs did not enter the fungal cells, but slightly destroyed the cell wall. UiO-66 NPs inhibited the laccase activity and promoted the activity of manganese peroxidase. The overall impact on the decomposition activity of P. chrysosporium was low in dye coloration test and sawdust degradation assay. Meaningful oxidative stress was aroused by UiO-66 NPs, as indicated by the decreases of catalase, glutathione, and total superoxide dismutase, and the increases of H 2 O 2 . Our results collectively suggested that the MOF particulates could induce mild mechanical damage to fungi and the toxicity was low comparing to other instable MOF materials., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022. Published by Elsevier Inc.)
Published: 2022
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30. The effects of inorganic anions on degradation kinetics and isotope fractionation during the transformation of tris(2-chloroethyl) phosphate (TCEP) by UV/persulfate.

Author: Liu J, Wei L, Zhang D, Tang L, Liu Y, Jing L, Liu J, and Yang S
Subjects: Anions, Carbon, Isotopes analysis, Kinetics, Oxidation-Reduction, Phosphates, Phosphines, Sulfates chemistry, Ultraviolet Rays, Water Pollutants, Chemical analysis, Water Purification
Abstract: Tris(2-chloroethyl) phosphate (TCEP), as a typical chlorinated flame retardant, is attracting more attention as a carcinogen. Although persulfate-based oxidation exhibits good performance in removing refractory organic pollutants, the kinetics of persulfate-based remediation are affected by inorganic anions, which causes inaccurate remediation efficiency. This study combines steady-state radical concentration modelling with isotope fractionation to investigate the effects of inorganic anions on TCEP degradation by UV/persulfate (UV/PS). In the absence of anions during UV/PS system, the observed degradation rate was (9.7 ± 0.1) × 10 -5 s -1 , which was approximately 93 % attributed to sulfate radical (SO 4 - •) oxidation based on radical modelling. Carbon isotope fractionation, coupled with the identification of transformation products by mass spectrometry, suggests a carbon bond split during TCEP degradation with a carbon isotopic fractionation value (ε) of -1.6 ± 0.2 ‰ (± 95 % confidence intervals). With respect to co-existing anions in UV/PS system, the addition of chloride (Cl - ) had a negligible effect on degradation rates, while the addition of hydrogencarbonate (HCO 3 - ) caused them to decrease, and the addition of hydrogenphosphate (HPO 4 2- ) caused them to increase. Radical modelling suggested that SO 4 - • was transformed to chlorine radicals (Cl•/Cl 2 - •), phosphate radicals (HPO 4 - •), and carbonate radicals (CO 3 - •). Furthermore, the overlapping 95 % confidence intervals (C.I.) and the statistical tests (p > 0.05) both agree that Cl - and HPO 4 2- gain identical ε values. Nevertheless, when HCO 3 - coexisted in the UV/PS system, the ε values were distinct. The addition of HCO 3 - would result in ε variation of TCEP in the UV activated PS process, which should receive more attention when applying remediation., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022. Published by Elsevier B.V.)
Published: 2022
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31. The response of bacterial community to UVB was significantly different between immature periphyton and mature periphyton, but not for physiological indicators.

Author: Zhang R, Zhao Y, Liu J, Yang S, and Jing L
Subjects: Antioxidants, Biomass, Photosynthesis, Ultraviolet Rays, Periphyton physiology
Abstract: Periphyton has important ecological functions. It can even exist in environments with strong ultraviolet radiation. However, knowledge of periphyton under ultraviolet is limited, which limits the understanding and application of periphyton in environments with high ultraviolet radiation. In this study, immature periphyton (IMP) and mature periphyton (MP) under ultraviolet B (UVB) irradiation were investigated and compared in terms of physiological characteristics and bacterial community. Analysis of the physiological characteristics showed that the response patterns of IMP and MP to UVB were similar. IMP and MP could adapt to UVB of 1 W/m 2 well. However, high-intensity UVB (2 and 3 W/m 2 ) reduced the periphyton biomass, inhibited photosynthesis and antioxidant enzyme activity and caused severe lipid peroxidation in both IMP and MP. Integrated Biological Response (IBR) analysis and toxicological model fitting showed that the ED 50 values of UVB for IMP and MP were 1.25 and 1.50 W/m 2 , respectively. 16 S rRNA gene analysis showed that in both IMP and MP, bacterial community composition, assembly and function were affected by UVB. In addition, the response of the bacterial community in IMP to UVB was stronger than that in MP. The diversity of the IMP community was inhibited by UVB, but that of the MP community was not. Proteobacteria and Deinococcus-Thermus are key microorganisms responsible for tolerance to UVB stress. Neutral community model fitting showed that both UVB and the development process caused the determinism of bacterial succession. However, UVB may weaken the deterministic process caused by development. Functional prediction showed that many metabolic functions of periphyton were inhibited by UVB in IMP and MP. However, UVB caused different changes (enhancement or inhibition) of some ecological functions in them. This study provides valuable information for understanding periphyton in environments with UVB radiation, which may be used to improve the application of periphyton in these environments., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)
Published: 2022
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32. Zwitterionic meso-silica/polypeptide hybrid nanoparticles for efficient azithromycin delivery and photodynamic therapy for synergistic treatment of drug-resistant bacterial infection.

Author: Xiang YL, Huang SH, Hu QH, Wang QY, Zhao MQ, Jiang YC, Chen X, Lin J, and Zhou QH
Subjects: Animals, Anti-Bacterial Agents pharmacology, Anti-Bacterial Agents therapeutic use, Azithromycin pharmacology, Azithromycin therapeutic use, Lipase pharmacology, Methylene Blue pharmacology, Mice, Microbial Sensitivity Tests, Peptides pharmacology, Peptides therapeutic use, Photosensitizing Agents pharmacology, Photosensitizing Agents therapeutic use, Silicon Dioxide pharmacology, Singlet Oxygen, Methicillin-Resistant Staphylococcus aureus, Nanoparticles, Photochemotherapy methods, Staphylococcal Infections drug therapy
Abstract: The treatment of drug-resistant bacterial infections attributed to the overuse of antibiotics still remains a serious challenge globally. Herein, zwitterionic charge switchable meso-silica/polypeptide hybrid nanoparticles (MSPNs) were prepared for the synergistic chemo-photodynamic therapy in the treatment of drug-resistant bacterial infections. Subsequently, azithromycin (AZT) and methylene blue (MB) were loaded in the MSPNs to form the combined chemo-photodynamic therapeutic nanoparticles (MSPNs-AZT/MB) for the treatment of methicillin-resistant Staphylococcus aureus (MRSA). Remarkably, the as-prepared MSPNs-AZT/MB exhibited a negative surface charge of -5.2 mV at physiological pH while switching into positive surface charge of 24.7 mv in an acidic environment, leading to enhanced binding with bacterial surface. The lipase-triggered AZT release up to 77.9 % was achieved, and the loaded MB demonstrated efficient singlet oxygen ( 1 O 2 ) generation for photodynamic therapy. The in vitro experimental results displayed an excellent antibacterial effect against MRSA in both planktonic and biofilm phenotypes. Additionally, the as-prepared MSPNs-AZT/MB exhibited synergistic and enhanced antibacterial infection effect up to 94 % comparing to monotherapy in a mice model. Considering the above advantages, the as-prepared combined chemo-photodynamic therapeutic nanoparticles showed promising biocompatibility and clinical potential for the efficient therapy of drug-resistant bacteria., (Copyright © 2022 Elsevier B.V. All rights reserved.)
Published: 2022
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33. Phytotoxicity of VO 2 nanoparticles with different sizes to pea seedlings.

Author: Li Q, Hu R, Chen Z, Chen L, Zhang J, Wu X, Li JB, Gao Y, Yang ST, and Wang H
Subjects: Germination drug effects, Plant Roots drug effects, Metal Nanoparticles chemistry, Metal Nanoparticles toxicity, Oxides toxicity, Pisum sativum drug effects, Seedlings drug effects, Vanadium Compounds toxicity
Abstract: Vanadium dioxide nanoparticles (VO 2 NPs) have been massively produced due to their excellent metal-insulator transition characteristics for various applications. Pilot studies indicated the toxicity of VO 2 NPs to bacteria and mammalian cells, but the environmental hazards of VO 2 NPs to plants have been unrevealed to date. In this study, we reported the inhibitive effects of VO 2 NPs to the growth and photosynthesis of pea seedlings. Laboratory synthesized monoclinic VO 2 NPs (N-VO 2 ), commercial nanosized VO 2 NPs (S-VO 2 ), and commercial microsized VO 2 particles (M-VO 2 ) were carefully characterized for environmental toxicity evaluations. VO 2 particles were supplemented to culture medium for seed germination and seedling growth. All three VO 2 samples did not affect the germination rates of pee seeds, while serious growth inhibition of pea seedlings was observed at 10 mg/L for S-VO 2 and N-VO 2 , and 100 mg/L for M-VO 2 . VO 2 particles had no impact on the chlorophyll contents, but the photosynthesis of leaf was significantly decreased following the consequence of N-VO 2 > S-VO 2 > M-VO 2 . The inhibition of photosynthesis was attributed to the damage of acceptor side of photosystem II by VO 2 particles at high concentrations. Abundant bioaccumulations of vanadium in roots aroused oxidative damage and changed the root structure. Our results collectively indicated that the phytotoxicity of VO 2 NPs was related to the concentration, size and crystalline degree., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)
Published: 2022
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34. The role of Tyr102 residue in the functioning of bacterial NAD + -dependent formate dehydrogenase of Pseudomonas sp. 101.

Author: Popinako АV, Pometun АА, Nilov DK, Dibrova DV, Khrustalev VV, Khrustaleva TA, Iurchenko TS, Nikolaeva АY, Švedas VK, Boyko KМ, Tishkov VI, and Popov VО
Subjects: Amino Acid Sequence, Formates, Phylogeny, Pseudomonas, Formate Dehydrogenases chemistry, Formate Dehydrogenases genetics, Formate Dehydrogenases metabolism, NAD metabolism
Abstract: Once you have missed the first button …, you'll never manage to button up Johann Wolfgang von Goethe Formate oxidation is a final step of methanol oxidation in methylotrophic prokaryotes and is important for detoxification of formate in other organisms. The structural mechanism of the formate dehydrogenase (FDH) of Pseudomonas sp. 101 has been studied for about 30 years. In the active center of FDH, the oxidation of formic acid into carbon dioxide in a NAD + -dependent way takes place. Residues that form the active center of that enzyme, as well as those that form the so-called substrate channel, are engaged in the catalytic cycle. Our study allowed to characterize a new residue, Tyr102, involved in the work of the enzyme. This residue is located in the outer neck of the substrate channel (at the beginning of the path of the substrate to the active center) and acts as a "button" which connects two enzyme domains into an active, "buttoned up" conformation. Our study of the kinetic parameters of mutant enzymes has shown that Tyr102Phe substitution leads to an approximately 80-fold increase of the Michaelis constant relative to the native enzyme, unlike Phe311Trp and Phe311Tyr substitution of neighboring residue Phe311. Our analysis of the Tyr102Phe mutant in the open conformation by X-ray crystallography has shown that its overall fold remains almost the same as that of the native enzyme. Molecular dynamics simulations of the ternary complexes of the native FDH enzyme and its Tyr102Phe mutant showed that Tyr102Phe substitution results in the loss of an interdomain hydrogen bond between the Tyr102 and Gln313 residues, which, in turn, destabilizes the closed conformation and affects the isolation of the FDH active site from water molecules. Our structural investigations have shown that Tyr102Phe replacement also leads to the destruction of interdomain contacts of Phe102 with Phe311, Pro312 residues, and decreases the stability of the Leu103-Val127 beta bridge. Phylogenetic analysis also confirmed the importance of the Tyr102 residue for enzymes from the FDH family, in which it is absolutely conserved., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Inc. All rights reserved.)
Published: 2022
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35. Surface charge switchable nano-micelle for pH/redox-triggered and endosomal escape mediated co-delivery of doxorubicin and paclitaxel in treatment of lung adenocarcinoma.

Author: Wang QY, Yali-Xiang, Hu QH, Huang SH, Lin J, and Zhou QH
Subjects: Animals, Doxorubicin chemistry, Drug Carriers therapeutic use, Drug Delivery Systems methods, Endosomes, Hydrogen-Ion Concentration, Mice, Micelles, Oxidation-Reduction, Paclitaxel, Tumor Microenvironment, Adenocarcinoma of Lung drug therapy, Neoplasms drug therapy
Abstract: Recently, the stimulus-sensitive drug co-delivery system has gained increasing attentions in the clinic and exhibits improved efficiency rather than the mono-chemotherapy in anti-tumor therapy. Herein, the smart charge switchable nano-micelles (NMs) were fabricated for the endosomal escape mediated co-delivery of doxorubicin (DOX) and paclitaxel (PTX) in treatment of lung adenocarcinoma. The disulfide bonds were facilitated as the linker of the polymer backbone to achieve the redox-sensitive degradation by high intracellular GSH, and acid-liable DMMA was grafted onto DOX molecules for pH-triggered drug release under acidic tumoral microenvironment. Folic acid (FA) was utilized as targeting molecule for facilitating entry of the as prepared NMs into cancer cells. Remarkably, the as fabricated NMs exhibited surface charge-switch from negative to positive during transmitting from physiological pH to the tumor extracellular pH, which can improve the cellular internalization towards cancer cell. Subsequently, the "proton-sponge" effect mediated endosome escape of the NMs was facilitated in the acidic endo/lysosome environment. By the cell assay, the NMs possessed good biocompatibility, excellent cellular uptake, and improved inhibition rate against cancer cell. Moreover, the co-delivery of DOX/PTX exhibited synergistic and enhanced solid tumor inhibition efficiency comparing to mono-chemotherapy in A-549 tumor bearing mice model. Based on above experimental results, the as prepared drug co-delivery system showed promising biosafety and potentials for efficient lung adenocarcinoma treatment in clinic., (Copyright © 2022. Published by Elsevier B.V.)
Published: 2022
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36. Toxicity and activity inhibition of metal-organic framework MOF-199 to nitrogen-fixing bacterium Azotobacter vinelandii.

Author: Ouyang B, Liu F, Liang C, Zhang J, Hu R, Yuan H, Hai R, Yuan Y, Wu X, and Yang ST
Subjects: Nitrogen, Nitrogen Fixation, Plastics, Azotobacter vinelandii, Metal-Organic Frameworks
Abstract: Metal-organic framework (MOF) materials with fantastic properties have found important applications in various areas. Learning the lessons from plastics and microplastics, it is urgent to investigate the environmental impacts of emerging materials to avoid potential pollution. However, the environmental toxicity and risks of MOF materials are seldom reported. Herein, we studied the toxicity and activity inhibition of MOF-199 to nitrogen-fixing bacterium Azotobacter vinelandii. MOF-199 significantly suppressed the growth of A. vinelandii and led to cell death at 40 mg/L. MOF-199 penetrated the cell wall and induced the shrinking of bacterial cells. MOF-199 reduced the nitrogen fixation activity of A. vinelandii at 40 mg/L by decreasing the gene nifH levels and inhibiting the Ca 2+ Mg 2+ -ATPase activity, which was further confirmed by the changes in oxidative phosphorylation related genes. Complete growth inhibition and activity loss of A. vinelandii occurred at 60 mg/L of MOF-199. The toxicological mechanism of MOF-199 to A. vinelandii was assigned to the oxidative stress, which occurred at 20 mg/L and higher. Both Cu 2+ release and particulates themselves contributed to the toxicity of MOF-199 to A. vinelandii. These findings highlighted the environmental hazards and risks of MOF materials to nitrogen-fixing bacteria and nitrogen fixation in the biogeochemical cycle., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)
Published: 2022
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37. Comparison of one-phase and two-phase extraction methods for porcine tissue lipidomics applying a fast and reliable tentative annotation workflow.

Author: Bögl T, Mlynek F, Himmelsbach M, and Buchberger W
Subjects: Animals, Mass Spectrometry, Solvents, Swine, Workflow, Lipidomics, Lipids
Abstract: Lipidomics has great potential for the discovery of biomarkers, elucidation of metabolic processes and identifying dysregulations in complex biological systems. Concerning biofluids like plasma or cerebrospinal fluid, several studies for the comparison of lipid extraction solvents have already been conducted. With respect to tissues, which can differ significantly in terms of dry matter content and composition, only few studies are available. The proper selection of an extraction method that covers the complexity and individuality of different tissues is challenging. The goal of this work was to provide a systematic overview on the potential of different extraction methods for a broad applicability. This study covers six different extraction procedures and four different reconstitution solvents applied to ten different porcine tissues. To get an overview of the individual lipid profiles, a workflow was developed for a fast and reliable tentative lipid annotation. Therefore, several machine learning tools were utilized, like the prediction of collision cross sections to support the tentative lipid identification in case of untargeted lipidomics. In terms of data evaluation, unsupervised (e.g. principal component analysis) and supervised (e.g. partial least square - discriminant analysis) methods were applied to visualize and subsequently interpret all generated information. Furthermore, the influence of the tissue composition on the extraction performance was investigated. It could be shown that the ten porcine tissues can be distinguished based on their lipid profile with the applied workflow and that the methyl-tert-butyl ether (MTBE) based extraction method (two-phase) showed the best overall performance for the 16 examined lipid species. With this method the highest number of features (428 in lung tissue) could be annotated. Upcoming one-phase extractions also showed a high potential concerning total number of extracted lipids. Methanol/MTBE/chloroform (MMC) extracted slightly less lipids (393 in lung and liver) than MTBE but turned out to be the best one-phase extraction method. Additionally, the numbers of extracted lipids obtained by isopropanol/water 90:10 (IPA90) (399 in stomach) and by isopropanol/methanol/chloroform (IMC) (395 in stomach) were similar to those of the modified Folch method (402 in stomach). One-phase extractions can therefore clearly be seen as preferable when a high throughput is needed., (Copyright © 2021. Published by Elsevier B.V.)
Published: 2022
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38. Study on the biological behaviors of CaP coatings with different morphology on carbon/carbon composites.

Author: Su Y, Li K, Vekeman J, Hessou EP, Tielens F, and Wang J
Subjects: Carbon, Prostheses and Implants, Surface Properties, Coated Materials, Biocompatible pharmacology, Mesenchymal Stem Cells
Abstract: In this work, we designed and fabricated a CaP composite bio-coating with different surface morphologies on a carbon/carbon (C/C) matrix by means of hybrid supersonic atmospheric plasma spraying (SAPS) and microwave-hydrothermal (MH) technologies. We found that all studied coating materials can support mesenchymal stem cells (MSCs) proliferation with prolonged culture time (3 days and 7 days) in vitro. Furthermore, according to the (Confocal Laser Scanning Microscopy) CLSM results, the MSCs also showed good attachment and different spreading morphologies on SAPS/MH coatings. As such, C/C matrix, the MH treated coatings with needle-like and rod-like microstructures were chosen for further in vivo investigation. Considering the good bonding between host tissue and the studied materials, the in vivo morphology studies confirmed a good histocompatibility for all coating samples, as well as a decreasing expression for inflammatory factors in a physiological environment. The histological results around the implants indicated different cell aggregation and vascularization ability in the local micro-environment. In particular, based on the reduction of the C/C initial surface flaws (e.g. hydrophobicity, biological inertia and easily producing carbon fragments or particles), the MH treated coating with rod-like surface morphology with a specific surface area (~2.33 m 2 /g) and roughness (~13.80 μm), showed excellent performance as a promising implant in live tissue., (Copyright © 2021 Elsevier B.V. All rights reserved.)
Published: 2021
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39. Spectra of tryptophan fluorescence are the result of co-existence of certain most abundant stabilized excited state and certain most abundant destabilized excited state.

Author: Vladislav Victorovich K, Tatyana Aleksandrovna K, Victor Vitoldovich P, Aleksander Nicolaevich S, Larisa Valentinovna K, and Anastasia Aleksandrovna A
Subjects: Fluorescence, Humans, Hydrogen Bonding, Proteins, Spectrometry, Fluorescence, Influenza A Virus, H1N1 Subtype, Tryptophan
Abstract: Fluorescence spectra of proteins and peptides are traditionally used to get an information on self-association of proteins and peptides, on their tertiary and quaternary structure. In this study it was shown that there are just three peaks of tryptophan fluorescence (at ∼308, at ∼330, and at ∼360 nm) in rough unsmoothed spectra of fluorescence of pure tryptophan in different solvents that change their heights depending on the polarity of a solvent. Two separate peaks at ∼330 nm and ∼360 nm are especially prominent in the spectrum of human epidermal growth factor. In contrast, in smoothed (either mathematically, or physically) spectra of Trp-containing proteins a single maximum of fluorescence varies between 330 and 360 nm. The theory of tryptophan fluorescence is discussed in light of three discrete peaks existence. A stabilizing hydrogen bond with aromatic system of benzene ring in the excited state is proposed as the cause of emission at ∼360 nm bringing Trp to the destabilized ground state. Emission from the destabilized excited state has a maximum at ∼330 nm if the ground state is destabilized, as well as if both states are stabilized. If the excited state is destabilized, while the ground state is stabilized by purely hydrophobic interactions, emitted light should have a maximum at ∼308 nm. The degree of hydrophilicity of tryptophan microenvironment is proposed to be measured as the ratio between the peak at 360 nm and the peak at 330 nm if the observed shifts are not "horizontal", but "vertical". The process of dissociation of hemagglutinin trimers from pandemic Influenza A(H1N1) virus is described as an example of the advantages of the proposed method., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)
Published: 2021
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40. Surface Minimal Bactericidal Concentration: A comparative study of active glasses functionalized with different-sized silver nanoparticles.

Author: Barzan G, Rocchetti L, Portesi C, Pellegrino F, Taglietti A, Rossi AM, and Giovannozzi AM
Subjects: Anti-Bacterial Agents pharmacology, Escherichia coli, Microbial Sensitivity Tests, Metal Nanoparticles, Silver pharmacology
Abstract: In this work the quantification of antimicrobial properties of differently sized AgNPs immobilized on a surface was studied. Three different sizes of spheroidal AgNPs with a diameter of (6, 30 and 52) nm were synthetized and characterized with UV-vis, SEM, TEM and ICP-MS. The MIC (Minimal Inhibitory Concentration) and MBC (Minimal Bactericidal Concentration) against Escherichia coli were investigated. Then, the antibacterial efficacy (R) of amino-silanized glasses coated with different amounts of the three sizes of AgNPs were quantified by international standard ISO 22196 adapted protocol against E. coli, clarifying the relationship between size and antibacterial properties of immobilized AgNPs on a surface. The total amount of silver present on glasses with an R ∼ 6 for each AgNPs size was quantified with ICP-MS and this was considered the Surface MBC (SMBC), which were found to be (0.023, 0.026 and 0.034) μg/cm 2 for (6, 30 and 52) nm AgNPs, respectively. Thus, this study demonstrates that active surfaces with a bactericidal effect at least ≥ 99.9999 % could be obtained using an amount of silver almost 100 times lower than the MBC found for colloidal AgNPs. The immobilization reduces the aggregation phenomena normally occuring in liquid media, maximizing the exposed specific superficial area of the AgNPs and their direct contact with bacterial cells. Starting from this glass model system, our work could broaden the way to the development of a wide range of antibacterial materials with very low amount of silver that can be safely applied in biomedical and food packaging fields., (Copyright © 2021 Elsevier B.V. All rights reserved.)
Published: 2021
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41. Photodynamic therapy for prostate cancer - A narrative review.

Author: Osuchowski M, Bartusik-Aebisher D, Osuchowski F, and Aebisher D
Subjects: Humans, Male, Photosensitizing Agents therapeutic use, Photochemotherapy methods, Prostatic Neoplasms drug therapy
Abstract: This article is a review of approaches to treatment of low and high-grade prostate cancer including a discussion of active treatment vs. active surveillance for patients with low-grade prostate cancer. In particular, we will review PDT as an option for active treatment of low-grade prostate cancer considered in light of recent clinical trials. The mechanism and clinical methods of PDT application and the key points from clinical trials using PDT for prostate cancer with the photosensitizers m-tetrahydroxyphenyl chloride, protoporphyrin IX, motexafin lutetium, padoporfin, and padeliporfin between the years 2002 and 2017 are reviewed. Recently developed methodologies for photodynamic prostate cancer treatment that are in the experimental stage, photodynamic diagnosis, fluorescence guided resection, and PSMA-targeted PDT will also be discussed., (Copyright © 2020 Elsevier B.V. All rights reserved.)
Published: 2021
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42. Effect of sprayed techniques on the surface microstructure and in vitro behavior of nano-HAp coatings.

Author: Su Y, Li K, Tielens F, and Wang J
Subjects: Corrosion, Materials Testing, Microscopy, Electron, Scanning, Surface Properties, Titanium, Coated Materials, Biocompatible, Durapatite
Abstract: Supersonic atmospheric plasma spray (SAPS) technique is a classical method which is employed to coat the carbon/carbon (C/C) composites by nano-hydroxyapatite (HAp) powders to decrease the biologically inert, hydrophobic drawbacks of substrate surfaces. In recent years, profiting from the promoting of energy conservation and environmental protection, more emphasis was placed on industrial manufacturing to simplify the experimental steps. This paper aims to study the preparation of nano-HAp coatings by suspension plasma spray (SPS) instead of the original SAPS technique. A denser, more uniform and less defective coating is successfully fabricated on C/C substrate using SPS technique. More important, fewer surface flaws in SPS coating could be observed by scanning electron microscopy (SEM) which shows that the large drawbacks of the coating have disappeared during spraying process. Meanwhile, except for HAp, phase compositions of the SPS coating appear with slight calcium oxide (CaO, 0.8%) and tricalcium phosphate (TCP, 30.7%), and then all CaO as well as TCP phases transform into dicalcium phosphate anhydrous (DCPA, 60.6%) after microwave-hydrothermal (MH) treatment. Thermal analysis (TG/DSC) reveals that SPS coating (97.51%) has a higher thermal stability than that of the SAPS coating (82.37%). Also, in comparison, the SPS coating after MH treatment (SPS-MH coating) exhibits better thermal properties (92.76%). In addition, compared to the SAPS and SPS coatings, due to the more flaw reduction and phase transformation, SPS-MH coating shows a better biological properties according to the surface microstructure in simulation body fluid (SBF) solution and cell spreading area on coating. The highest corrosion resistance with the current density of 3.9798 × 10 -7 A/cm 2 and a potential of 0.0419 V is achieved for SPS-MH coating., Competing Interests: Declaration of competing interest The authors declared that they have no conflicts of interest to this work. We declare that we do not have any commercial or associative interest that represents a conflict of interest in connection with the work submitted., (Copyright © 2020. Published by Elsevier B.V.)
Published: 2020
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43. The role of autofluorescence, photodynamic diagnosis and Photodynamic therapy in malignant tumors of the duodenum.

Author: Krupka M, Bartusik-Aebisher D, Strzelczyk N, Latos M, Sieroń A, Cieślar G, Aebisher D, Czarnecka M, Kawczyk-Krupka A, and Latos W
Subjects: Duodenum diagnostic imaging, Humans, Photosensitizing Agents therapeutic use, Prognosis, Neoplasms, Photochemotherapy methods
Abstract: This article presents the current state of knowledge and a review of the literature in terms of the prevalence, etiopathogenesis, differential diagnosis, management, prognosis, and treatment of malignant tumors of the duodenum. The role of autofluorescence and photodynamic diagnosis as an emerging treatment method for rarely o ccurring duodenal malignant neoplasms .. We selected publications which can be found in databases such as The National Center for Biotechnology Information, U.S. National Library of Medicine (PubMed), The American Chemical Society, The American Association of Pharmaceutical Sciences and The American Society for Photobiology and The Canada Institute for Scientific and Technical Information., (Copyright © 2020 Elsevier B.V. All rights reserved.)
Published: 2020
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44. Nanomechanical properties of zirconium anodized in a mixture of electrolytes with fluoride ions.

Author: Pantazi A, Vardaki M, Mihai G, Totea G, Demetrescu I, and Enachescu M
Subjects: Cross-Sectional Studies, Microscopy, Electron, Scanning, Surface Properties, Titanium, Fluorides, Zirconium
Abstract: The present work introduces nanostructured Zr as a possible choice of metallic implant biomaterial in competition with titanium and its new alloys. The paper reports on the preparation of anodized zirconium in a mixture of electrolytes with fluoride ions, 1 M (NH 4 )2SO 4 + 0.15 M NH 4 F + distilled water, at 20 V. The obtained nanostructures were investigated by SEM, EDX, XRD and AFM techniques. The SEM - EDX longitudinal and cross sectional analysis revealed the morphology of the formed oxide layers and their thicknesses, which were found to be 7.45 ± 0.18 μm. The mean nanopores' diameter was calculated as 15.8 ± 3.3 nm. The XRD investigations enabled the evaluation of crystallite sizes and texture coefficients for zirconium and zirconium oxide containing samples. The inhibition effect against Escherichia coli and Streptococcus Aureus bacteria was evaluated and discussed as well. The AFM studies revealed that the nano-porous Zr has similar hardness parameter as the uncoated Zr, but lower surface adhesion force that could be translated into improved properties in terms of antimicrobial effects, as confirmed by its inhibition index, which makes it a very promising material for bio-medical applications., (Copyright © 2020 Elsevier Ltd. All rights reserved.)
Published: 2020
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45. Five new cassane diterpenes from the seeds and bark of Erythrophleum suaveolens.

Author: Kablan ACL, Konan JD, Komlaga G, Kabran FA, Daouda B, N'Tamon AD, Kouamé T, Jagora A, Leblanc K, Seon-Méniel B, Beniddir MA, Attioua KB, Le Pogam P, and Champy P
Subjects: Antineoplastic Agents, Phytogenic isolation & purification, Cell Line, Tumor, Cote d'Ivoire, Diterpenes isolation & purification, Humans, Molecular Structure, Phytochemicals isolation & purification, Phytochemicals pharmacology, Antineoplastic Agents, Phytogenic pharmacology, Diterpenes pharmacology, Fabaceae chemistry, Plant Bark chemistry, Seeds chemistry
Abstract: Five new cassane-type diterpenoid heterosides, i. e. two cassane-type amides (1-2), two erythrophlamine-type amine esters (3-4) and a non‑nitrogenous erythrophlamine analogue (5) were isolated from the root barks (1-2) and the seeds (3-5) of Erythrophleum suaveolens. Their structures were unambiguously established by interpretation of their HRESIMS, 1D and 2D NMR data, and chemical degradation for sugar determination. Compounds 3-5 were evaluated for their cytotoxicity against a panel of three cell lines, revealing modest to strong activities., Competing Interests: Declaration of Competing Interest The authors declare no conflict of interest for this study., (Copyright © 2020 Elsevier B.V. All rights reserved.)
Published: 2020
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46. Preliminary evaluation of application of a 3-dimensional network structure of siloxanes Dergall preparation on chick embryo development and microbiological status of eggshells.

Author: Patrzałek M, Kosecka-Strojek M, Lisowska-Łysiak K, Trela M, Kot M, Gawlak M, Liszka D, Sajewicz M, Tombarkiewicz B, Pawlak K, Międzobrodzki J, and Lis MW
Subjects: Animals, Anti-Bacterial Agents administration & dosage, Anti-Bacterial Agents chemistry, Bacteria growth & development, Bacterial Physiological Phenomena drug effects, Chick Embryo growth & development, Chickens, Dose-Response Relationship, Drug, Egg Shell microbiology, Siloxanes administration & dosage, Siloxanes chemistry, Anti-Bacterial Agents pharmacology, Bacteria drug effects, Chick Embryo drug effects, Egg Shell drug effects, Siloxanes pharmacology
Abstract: The spatial network structure of Dergall is based on substances nontoxic to humans and the environment which, when applied on solid surfaces, creates a coating that reduces bacterial cell adhesion. The bacteriostatic properties of siloxanes are based on a purely physical action mechanism which excludes development of drug-resistant microorganisms. The aims of the present study were to 1) evaluate a Dergall layer formed on the eggshell surface regarding the potential harmful effects on the chick embryo; 2) evaluate antimicrobial activity and estimate the prolongation time of Dergall's potential antimicrobial activity. Dergall at a concentration of 0.6% formed a layer on the eggshell surface. In vitro testing of the potential harmful effects of Dergall by means of a hen embryo test of the chorioallantoic membrane showed no irritation reaction at a concentration of 3% and lower. The hatchability of the groups sprayed with a Dergall water solution with a concentration of 0 to 5% was 89.1 to 93.8% for fertilized eggs (P > 0.05) but decreased to 63.7% (P < 0.05) in the group sprayed with a 6% concentration of the solution. This phenomenon was caused by embryo mortality in the first week of incubation. At the concentration of 0.6%, Dergall exhibited strong antibacterial properties against bacteria such as Staphylococcus aureus, Escherichia coli, Shigella dysenteriae, Shigella flexneri, and Salmonella typhimurium. For Streptococcus pyogenes, the highest antibacterial activity of Dergall was reported in the concentrations of 100 and 50%. For Pseudomonas aeruginosa, no antibacterial activity of Dergall was generally observed, but in vivo testing showed a strong decrease of all gram-negative bacteria growth. Moreover, a prolonged antimicrobial effect lasting until 3 D after disinfection was observed, which makes Dergall a safe and efficient disinfectant., (Copyright © 2019. Published by Elsevier Inc.)
Published: 2020
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47. Determination of bisphenol A in canned food by microwave assisted extraction, molecularly imprinted polymer-solid phase extraction and liquid chromatography-mass spectrometry.

Author: Maragou NC, Thomaidis NS, Theodoridis GA, Lampi EN, and Koupparis MA
Subjects: Chromatography, High Pressure Liquid methods, Limit of Detection, Linear Models, Microwaves, Reproducibility of Results, Spectrometry, Mass, Electrospray Ionization methods, Benzhydryl Compounds analysis, Food, Preserved analysis, Molecular Imprinting methods, Phenols analysis, Solid Phase Extraction methods
Abstract: Bisphenol A (BPA), a known potential endocrine disrupting compound (EDC) is expected to be present in low quantities in canned food due to its migration from the inner surface coating of cans made of epoxy resins. A selective and confirmatory analytical method, based on microwave assisted extraction (MAE), molecularly imprinted solid phase extraction (MISPE) using a polymer prepared by a non-covalent molecular imprinting technique and liquid chromatography coupled with electrospray ionization mass spectrometry (LC-ESI/MS) was developed for the determination of BPA in canned pineapple, tuna and mushrooms. First, the effect of the loading medium of hydro- organic solutions on the binding of BPA and its deuterated analogue on the MISPE sorbent was investigated. Subsequently, the effects of the experimental conditions of the microwave assisted extraction (solvent, sample mass/solvent volume, time and temperature) on the obtained recovery of BPA from canned food were assessed and the parameters were optimized to provide maximum recovery and selectivity. It was demonstrated that the combination of MAE with MISPE permits the use of a selective extraction solvent (methanol/water, 4/6, v/v), simplifying the sample preparation steps and enhancing sample clean-up of complex food matrices. The method was validated in different food matrices, using BPA-d16 as internal standard and quantitative relative recoveries were determined. The precision (RSD %) of the method ranged from 7% to 10% and the limit of detection was at low ng/g level for all food matrices. The determined concentration of BPA in commercial canned samples ranged between 7.3 and 42.3 ng/g., (Copyright © 2019 Elsevier B.V. All rights reserved.)
Published: 2020
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48. Nanotubes and nano pores with chitosan construct on TiZr serving as drug reservoir.

Author: Stoian AB, Demetrescu I, and Ionita D
Subjects: Coated Materials, Biocompatible pharmacology, Drug Liberation, Gentamicins pharmacology, Kinetics, Spectroscopy, Fourier Transform Infrared, Surface Properties, Water chemistry, Alloys chemistry, Chitosan chemistry, Nanopores, Nanotubes chemistry
Abstract: Taking into account that modified and non modified TiZr alloys have a chance as alternatives for Ti as implant materials, this paper is focused on the elaboration and characterization of TiZr hybrid nanostructures (nanopores and nanotubes) loaded with gentamicin (GS) and covered with chitosan. FT-IR analysis permitted structure and corresponding bands identification. Scanning electronic microscopy (SEM) was used for morphology analysis and nanostrucure dimensions evaluations. The surface analysis was completed with roughness measurements, contact angle determinations and surface energy evaluations. The amount of drug released in both cases was measured using ultraviolet-visible spectroscopy (UV/Vis). The in-vitro drug release profile was applied to three kinetic mathematical models (Korsmeyer-Peppas, Peppas-Sahlin and Linder-Lippold). Using the experimental data on the three simulation models, the Lindner-Lippold was found to be the best suited for the transport mechanism dominated by Fickian diffusion. It was observed that the same quantity of gentamicin (approx. 95%) will be released in 10 days from nanopores and in 21 days from nanotubes, establishing in both cases longer term release as an expression of better targeted treatment of bone and osteomyelitis., (Copyright © 2019 Elsevier B.V. All rights reserved.)
Published: 2020
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49. Mutational pressure and natural selection in epidermal growth factor receptor gene during germline and somatic mutagenesis in cancer cells.

Author: Khrustalev VV, Khrustaleva TA, Poboinev VV, and Yurchenko KV
Subjects: Amino Acid Substitution genetics, Antineoplastic Agents pharmacology, ErbB Receptors genetics, Humans, Germ Cells metabolism, Mutagenesis genetics, Mutation, Missense genetics, Selection, Genetic genetics
Abstract: In this study we investigated nucleotide usage biases along the length of a gene encoding human epidermal growth factor receptor (EGFR) and found out that there had been mutational GC-pressure with stronger asymmetric C-pressure in that gene before the preferable direction of nucleotide mutations changed. Current preferable direction of germline mutations in EGFR gene has been estimated with the help of Ensembl data base of gene variations. Preferable direction of somatic mutations in EGFR gene from cancer cells has been estimated with the help of COSMIC data base. Both germline and somatic mutations in cancer cells have the same GC to AT preferable direction in EGFR gene. These data have been used with the aim to find fragments of EGFR gene that have lower probability of missense C to T and G to A transitions to occur. So, the less mutable parts of extracellular EGFR domain are: C-terminal part of the first beta barrel and the central part of the second beta barrel. The less mutable parts of tyrosine kinase EGFR domain are: ATP-binding site (partially), regulatory alpha helix, and fragments that change their secondary structure during the activation process. These parts of EGFR should be considered as the best targets for new types of therapy development. Such criterion as low mutability is especially important for the selection of targets for anti-tumor therapy, since we have detected positive selection of amino acid replacements during somatic mutagenesis of EGFR gene in cancer cells., (Copyright © 2019 Elsevier B.V. All rights reserved.)
Published: 2019
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50. Thermal decomposition of bimetallic titanium complexes: A new method for synthesizing doped titanium nano-sized catalysts and photocatalytic application.

Author: Absalan Y, Ryabov MA, and Kovalchukova OV
Subjects: Bromphenol Blue chemistry, Catalysis, Cobalt chemistry, Light, Manganese chemistry, Molecular Conformation, Nickel chemistry, Photolysis, Quantum Theory, Salicylic Acid chemistry, Spectroscopy, Fourier Transform Infrared, Thermogravimetry, Ultraviolet Rays, Coordination Complexes chemistry, Nanoparticles chemistry, Titanium chemistry
Abstract: In this study, synthesis of bimetallic (Co, Mn, and Ni) complexes of salicylic acid (L 1 ) and 1,2 dihydroxybenzene (L 2 ) based on titanium(IV) were investigated, then the samples were decomposed by thermal method to obtain M x Ti y O z nanoparticles (M = Ni, Co, and Mn). The samples in complexes mode were analyzed by UV-Vis (200-800 nm), FT-IR (4000-400 Cm -1 ), CHN analysis and the structure of the bimetallic compounds also were investigated by the Quantum-chemical modelling. In addition, the samples in nanoparticles mode were studied by thermal analysis (to obtain DTA curves), XRD, FESEM image and EDX analyzing. BET surface analysis was carried out to analyze active surface, pore diameter and porosity of the M x Ti y O z nanoparticles. Based on the results, obtained samples as catalysts were able to absorb not just UV but also visible light. Catalysts were able to degrade bromophenol blue as a harmful organic substance under UV and visible lights, although, this ability was more significant when the samples were used under visible light., (Copyright © 2018. Published by Elsevier B.V.)
Published: 2019
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