journal
MENU ▼
Read by QxMD icon Read
search

Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry

journal
https://www.readbyqxmd.com/read/30417568/revisiting-the-origination-of-bacterial-bioluminescence-a-qm-mm-study-on-oxygenation-reaction-of-reduced-flavin-in-protein
#1
Yanling Luo, Ya-Jun Liu
Bacterial bioluminescence is initiated by the oxygenation reaction of reduced flavin mononucleotide in the luciferase. This enzymatic oxygenation occurs in a wide range of biological processes including cellular redox metabolism, biocatalysis, biosynthesis and homeostasis. However, little is known about the mechanism of enzymatic reaction between singlet reduced flavin and triplet oxygen. To explore the enigmatic oxygenation, for the first time, the reaction of reduced flavin anion with oxygen was studied in the bacterial luciferase by combined quantum mechanics and molecular mechanics (QM/MM) method as well as molecular dynamics (MD) simulation...
November 11, 2018: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/30412344/energetic-topological-and-electric-field-analyses-of-cation-cation-nucleic-acid-interactions-in-watson-crick-disposition
#2
Ibon Alkorta, Ignasi Mata, Elies Molins, Enrique Espinosa
A theoretical study of the effect of the diprotonation on the nucleic acid bases (A:U, A:T and G:C) in Watson-Crick conformation has been carried out by means of DFT computational methods in vacuum. In addition, the corresponding neutral and monoprotonated binary complexes have been considered. Most of the diprotonated species studied are stable, even though the binding energy is positive due to the overall repulsive electrostatic term. Local electrostatic attractive forces in the regions of hydrogen bonds (HBs) are responsible for equilibrium geometries, as shown by the electric field lines connecting the electrophilic and nucleophilic sites involved in the HB interactions...
November 9, 2018: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/30411453/probing-the-adsorption-configurations-of-small-molecules-on-surfaces-by-single-molecule-tip-enhanced-raman-spectroscopy
#3
Yao Zhang, Rui Zhang, Song Jiang, Yang Zhang, Zhen-Chao Dong
The determination of the adsorption configurations of organic molecules on surfaces, especially for relatively small molecules, is a key issue for understanding the microscopic physical and chemical processes in surface science. In this work, we have applied the low-temperature ultrahigh-vacuum tip enhanced Raman scattering (TERS) technique to distinguish the configurations of small 4,4'-bipyridine (44BPY) molecules adsorbed on the silver surface. The observed Raman spectra exhibit notable differences in the spectral features which can be assigned to three different molecular orientations, each featuring a specific fingerprint pattern based on the TERS selection rule that determines the distribution of the relative intensities of different vibrational peaks...
November 9, 2018: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/30403318/in-situ-second-harmonic-generation-circular-dichroism-with-submonolayer-sensitivtiy
#4
Alexander von Weber, Matthias Jakob, Eva Kratzer, Aras Kartouzian, Ueli Heiz
In this work, we present an experimental setup for the in situ and ex situ study of the optical activity of samples, which can be prepared under ultra-high vacuum (UHV) conditions by second-harmonic generation circular dichroism (SHG-CD) over a broad spectral range. The use of a racemic mixture as a qualified reference for the anisotropy factor is described and, as an example, the chiroptical properties of 1.5 μm thick (multilayers) as well as sub-monolayer thin films of the R- and S-enantiomer of 1,1'-Bi-2-naphthol (BINOL) evaporated onto BK7 substrates were investigated...
November 7, 2018: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/30397996/t-si64-a-novel-si-allotrope
#5
Qingyang Fan, Rui Niu, Wenzhu Zhang, Wei Zhang, Yingchun Ding, Sining Yun
Utilizing the first principle calculation, a novel Si64 silicon allotrope in the I41/amd space group with tetragonal symmetry (denoted as t-Si64 below) was proposed in this work, and its structural properties, mechanical anisotropy properties, electronic properties and minimum thermal conductivity κmin were also predicted. The mechanical stability and thermodynamic stability of t-Si64 were proven by elastic constants and phonon spectra. The electronic band structure resolution determined that t-Si64 is an indirect band gap semiconductor material, as shown by a primitive cell (band gap: 0...
November 6, 2018: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/30395699/catalyst-substrate-effects-on-biocompatible-sabre-hyperpolarization
#6
Anand Manoharan, Peter J Rayner, Marianna Fekete, Wissam Iali, Philip Norcott, V Hugh Perry, Simon Duckett
The hyperpolarization technique, Signal Amplification by Reversible Exchange, has the potential to improve clinical diagnosis by making molecular magnetic resonance imaging in vivo a reality. Essential to this goal is the ability to produce a biocompatible bolus for administration. We seek here to determine how the identity of the catalyst and substrate affects the cytotoxicity by in vitro study, in addition to reporting how the use of biocompatible solvent mixtures influence the polarization transfer efficiency...
November 5, 2018: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/30387542/enhancement-of-nuclear-spin-noise-signal-using-wavelet-transform
#7
D Adilakshmi, Kousik Chandra, K V Ramanathan
Spin Noise spectroscopy has attracted considerable attention recently owing partly to intrinsic interest in the phenomenon and partly to its significant application potential. Here we address the inherent problem of low sensitivity of nuclear spin noise and examine the utility of wavelet transform to mitigate this problem by distinguishing real peaks from the noise contaminated data. Suppression of the random circuit noise and the consequent enhancement of the correlated nuclear spin noise signal have been demonstrated with discrete wavelet transform...
November 2, 2018: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/30381883/design-synthesis-and-computational-study-of-fluorinated-quinoxaline-oligothiophene-based-conjugated-polymers-with-broad-spectral-coverage
#8
Desta Antenehe Gedefaw, Svante Hedström, Yuxin Xia, Petter Persson, Mats Andersson
Donor-acceptor (D-A) copolymers typically show two absorption peaks in the visible region, flanking a valley region of limited absorptivity. One strategy for more panchromatic light harvesting is to incorporate side-groups orthogonal to the polymer backbone, which enable 2D π conjugation and can give rise to additional absorption peaks. Here we design and synthesize two D-A polymers which both carry a fluorinated quinoxaline acceptor unit, but while P1 includes a benzodithiophene donor moiety with thiophene side-groups (2D-BDT), the P2 polymer lacks 2D conjugation in its simpler pentathiophene donor segment...
October 31, 2018: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/30371980/hydroxyl-groups-of-exceptionally-high-acidity-in-desilicated-zeolites-y
#9
Mariusz Gackowski, Łukasz Kuterasiński, Jerzy Podobiński, Jerzy Datka
The desilication of dealuminated zeolite Y in NaOH/tetrabutylammonium hydroxide mixtures produces hierarchical zeolite Y containing micropore system as well as mesopores of significant volume and surface. IR studies evidenced, that a new kind of hydroxyls was formed if desilication was realized above 318 K. This new kind of acidic hydroxyls is characterized by IR band at 3600 cm-1. IR studies showed, that these new hydroxyls showed extremely high acidity. This was evidenced by very high frequency shifts of IR bands of OH interacting with probe molecules: CO and N2: Δν OH...
October 29, 2018: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/30371006/tinf-and-related-analogues-of-tio2-a-combined-experimental-and-theoretical-study
#10
Mohd Monis Ayyub, Suchitra Prasad, Srinivasa Rao Lingampalli, Krishnappa Manjunath, Umesh V Waghmare, C N R Rao
Aliovalent anion substitution in inorganic materials brings about marked changes in properties as exemplified by N,F-codoped metal oxides. Recently, complete substitution of oxygen in ZnO by N and F has been carried out to generate Zn2NF. In view of the important properties of TiO2, we have attempted to prepare TiNF by employing an entirely new procedure involving the reaction of TiN with TiF4. While the reaction at low temperature (450ºC) yields TiNF in the anatase phase, reaction at a higher temperature (600ºC) yields TiNF in the rutile phase...
October 29, 2018: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/30370996/niobium-doping-in-bivo4-an-interplay-between-effective-mass-stability-and-pressure
#11
Hori Pada Sarker, Pratap M Rao, Muhammad N Huda
We have applied density functional theory to study the electronic structure changes caused by Nb incorporation in BiVO4 and the application of external pressure. The overall solubility of Nb in BiVO4 is usually high, and the presence of oxygen vacancies affect the dopability of Nb in BiVO4. Through the analyses of the chemical-potential landscape, we have determined the single-phase stability zone of BiVO4 with the Nb doping. The most favorable Nb doping is simultaneous substitutions at both V and Bi sites...
October 29, 2018: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/30370987/the-structural-signs-of-sweetness-in-artificial-sweeteners-a-rotational-study-of-sorbitol-and-dulcitol
#12
Elena Alonso, Iker León, Lucie Kolesnikova, Jose Luis Alonso
The gas phase study of the artificial sweeteners sorbitol and dulcitol has been carried out for the first time, using a combination of chirped pulse Fourier transform microwave (CP-FTMW) spectroscopy coupled with a laser ablation (LA) source. The isolation conditions provided by the supersonic expansion reveal the intrinsic conformational structures of these sweeteners. The three and five observed conformers for sorbitol and dulcitol, respectively, are stabilized by networks of cooperative intramolecular hydrogen bonds between vicinal hydroxyl groups in clockwise or counterclockwise arrangements...
October 29, 2018: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/30370986/arch-sub-2-sub-sup-sup-a-detectable-noble-gas-molecule
#13
Ryan C Fortenberry, Daniela Ascenzi
The noble gas molecular cation, ArCH<sub>2</sub><sup>+</sup>, has been observed in mass spectrometry experiments, and the present work is providing high-level quantum chemical predictions for the vibrational and rotational spectroscopic data necessary to observe this molecule <italic>in situ</italic> in other laboratory conditions. The Ar-C stretch in this cation is a bright fundamental vibrational frequency that should be observable in the early regions of the far-infrared at 421...
October 29, 2018: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/30358054/interacting-quantum-atoms-approach-and-electrostatic-solvation-energy-assessing-atomic-and-group-solvation-contributions
#14
Fernando Jiménez-Grávalos, Natalia Díaz, Evelio Francisco, Angel Martín-Pendás, Dimas Suarez
The interacting quantum atoms (IQA) method decomposes the total energy of a molecular system in terms of one- and two-center (atomic) contributions within the context of the quantum theory of atoms in molecules. Here we incorporate electrostatic continuum solvent effects into the IQA energy decomposition. To this end, the interaction between the solute electrostatic potential and the solvent screening charges as defined within the COSMO solvation model is now included in a new version of the PROMOLDEN code, allowing thus to apply IQA in combination with COSMO-quantum chemical methods as well as to partition the electrostatic solvation energy into effective atomic and group contributions...
October 25, 2018: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/30358053/crowding-and-confinement-can-oppositely-affect-protein-stability
#15
Kai Cheng, Qiong Wu, Zeting Zhang, Gary J Pielak, Maili Liu, Conggang Li
Proteins encounter crowded and confined macromolecular milieus in living cells. Simple theory predicts that both environments entropically stabilize proteins if only hard-core repulsive interactions are considered. Recent studies show that chemical interactions between the surroundings and the test protein also play key roles such that the overall effect of crowding or confinement is a balance of hard-core repulsions and chemical interactions. There are, however, few quantitative studies. Here, we quantify the effects of crowding and confinement on the equilibrium unfolding-thermodynamics of a model globular protein, KH1...
October 24, 2018: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/30358034/boolean-logic-gates-realized-with-enzyme-catalyzed-reactions-unusual-look-at-usual-chemical-reactions
#16
Evgeny Katz
Research in the area of molecular computing systems, in the general framework of unconventional computing, has received high attention and resulted in rapid progress in formulating signal-controlled switchable molecules capable to perform Boolean logic operations and basic arithmetic functions. Extension of this research to biomolecular systems allowed sophisticated computational functions much easier than using synthetic molecular and supramolecular species. The advantage of biomolecular systems comparing with synthetic molecular systems is in their complementarity and compatibility allowing easy assembling multi-component systems from various biomolecules, thus increasing their functional complexity...
October 24, 2018: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/30353626/highly-stable-and-active-cu1-ceo2-single-atom-catalyst-for-co-oxidation-a-dft-study
#17
Lan Qin, Yunqi Cui, Tao-Li Deng, Fu-Hua Wei, Xiang-Fei Zhang
We carry out density functional theory simulations to examine the stability and CO oxidation activity of Cu single atom on CeO2(111). The strong binding energy and high activation energy for Cu single atom diffusion both indicate the high stability of Cu1/CeO2 single-atom catalyst. Electronic structure analysis verifies the formation of Cu+ cation due to electron transfer. The frequency analysis further corroborates that the experimentally observed IR bands around 2114-2130 cm-1 of CO adsorption at the boundary of Cu/CeO2 correspond to Cu+-carbonyl species...
October 23, 2018: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/30353624/sequential-ultrafast-energy-transfer-and-electron-transfer-in-a-fused-zinc-phthalocyanine-free-base-porphyrin-c60-supramolecular-triad
#18
Sairaman Seetharaman, Paul Karr, Athanassios Coutsolelos, Fernando Lazaro, Angela Sastre Santos, Francis D'Souza
A supramolecular triad composed of a fused zinc phthalocyanine-free-base porphyrin dyad (ZnPc-H2P) coordinated to phenylimidazole functionalized C60 via metal-ligand axial coordination was assembled, as a photosynthetic antenna-reaction centre mimic. The process of self-assembly resulting into the formation of C60Im:ZnPc-H2P triad was probed by proton NMR, UV-Visible and fluorescence experiments. The geometry and electronic structures were deduced from DFT calculations performed at the B3LYP/6-31G(dp) level...
October 23, 2018: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/30350435/the-influence-of-the-amino-acid-side-chains-on-the-raman-optical-activity-spectra-of-proteins
#19
Carl Mensch, Christian Johannessen
The Raman optical activity (ROA) spectra of proteins show distinct patterns arising from the secondary structure. It is generally believed that the spectral contributions of the side-chains largely cancel out because of their flexibility and the occurrence of many side-chains with different conformations. Yet, the influence of the side-chains on the ROA patterns assigned to different secondary structures is unknown. Here, the first systematic study of the influence of all amino acid side-chains on the ROA patterns is presented based on density functional theory (DFT) calculations of an extensive collection of peptide models that include many different side-chain and secondary structure conformations...
October 22, 2018: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/30347503/in-situ-formation-of-gold-nanoparticles-within-a-polymer-particle-and-their-catalytic-activities-in-various-chemical-reactions
#20
Wongi Jang, Richard Taylor Iv, Pascal N Eyimegwu, Hongsik Byun, Jun Hyun Kim
Composite materials consisting of nanoscale gold particles and protective polymer shells were designed and tested as catalysts in various chemical reactions. Initially, the systematic incorporation of multiple gold nanoparticles into a poly(N-isopropylacrylamide) particle was achieved by an in situ method under light irradiation. The degree of gold nanoparticle loading, along with the structural and morphological properties, was examined as a function of the amount of initial gold ions and reducing agent. As these gold nanoparticles were physically-embedded within the polymer particle in the absence of strong interfacial interactions between the gold nanoparticles and polymer matrix, the readily-accessible surface of the gold nanoparticles with a highly increased stability allowed for their use as recyclable catalysts in oxidation, reduction, and coupling reactions...
October 22, 2018: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
journal
journal
34984
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"