A DFT study on degradation of aflatoxin B1 using some reactive oxygen and nitrogen species of plasma-activated water.

The degradation mechanism of aflatoxin B1 using some reactive oxygen and nitrogen species of plasma-activated water have been investigated theoretically at the M06-2X/aug-cc-pVTZ//M06-2X/6-31G(d) level. Diffusion rate coefficient for all studied reactions was calculated to be ∼10 M s and related activation energy was about 18-19 kJ mol. The most favorable pathways of degradation were addition the vinyl bond of terminal furan ring.

MoS-Based nanocomposite for synergistic chemo-photothermal cancer therapy.

MoS₂ nanoflakes are emerging as a promising material for photothermal therapy due to their high absorption in the NIR region, large specific surface area, biocompatibility, efficient photothermal conversion, and ability to be functionalized for targeted therapy. In this paper, MoS₂ nanoflakes were incorporated to FeO nanoparticles, gold nanorod (GNR), and copper sulfide (CuS) (MCG nanocomposite) to investigate chemo-photothermal therapy in this nanocomposite. The structural and optical properties of the MCG nanocomposite were characterized by X-ray diffraction (XRD), Transmission electron microscopy (TEM), Zeta potential, Dynamic Light Scattering (DLS), Fourier transform infrared (FTIR), and Ultraviolet-visible (UV-Vis) spectroscopies.

Cerium(III) immobilized on the functionalized halloysite as a highly efficient catalyst for aza-Diels-Alder reaction.

Aza-Diels-Alder cycloaddition reaction is a critical synthetic method for the production of bioactive tetrahydroquinolines. To this aim, an imine obtained from the reaction of an aniline derivative and a carbonyl compound is cyclized with an alkene in the presence of a catalyst. In this research, some tetrahydroquinoline compounds are synthesized through aza-Diels-Alder reaction in the presence of a prepared Ce(III) immobilized on the functionalized halloysite (Ce/Hal-TCT-IDA) as a catalyst.

Regeneration of combined severe periodontal defects and vertical ridge defects using recombinant human platelet-derived growth factor-BB: A case series.

Dental implants are a reliable treatment option for restoring missing teeth, but adequate bone quantity and quality are crucial for success. This case series presents four cases treated by different clinicians, all following very similar concepts for combined periodontal and vertical ridge augmentation using recombinant human platelet-derived growth factor-BB. All cases involved a severe periodontal defect requiring either extraction of the adjacent tooth or periodontal regeneration.

Palladium doped PDA-coated hercynite as a highly efficient catalyst for mild hydrogenation of nitroareness.

Hercynite magnetic nanoparticles were produced through the co-precipitation of ferrous and aluminum cations. The surface of hercynite was respectively coated with silica, 2,4,6-trichloro-1,3,5-triazine, and 1H-pyrazole-3,5-dicarboxylic acid to provide a suitable substrate for Pd(II) loading, furnishing Pd@Her-TCT-PDA. Subsequently, the introduced Pd(II) was reduced to Pd(0) using NaBH.

Theoretical investigation on the mechanism and kinetics of the OH‒initiated atmospheric degradation of p-chloroaniline: Addition of ∑3O and isomerization of peroxy radicals.

Atmospheric oxidation of the p-chloroaniline-OH adduct [CHClNH-OH] (AD-C2) by ∑3O and internal isomerization processes of peroxy radical [CHClNH-OH]-O are theoretically investigated at the M06-2X/aug-cc-pVTZ and CBS-QB3//M06-2X/aug-cc-pVTZ level of theories. Potential energy surfaces (PESs) for the most efficient pathways indicated that the oxidation process begins via the complexation of individual reactants in syn mode forming PRCy-iOO-syn (y = 2,5) in an exothermic and endogenic step. The syn mode addition is favored over the anti one due to the formation of internal hydrogen bond between the hydroxyl and peroxy groups.

Understanding the kinetics and atmospheric degradation mechanism of chlorotrifluoroethylene (CFCFCl) initiated by OH radicals.

The atmospheric degradation of chlorotrifluoroethylene (CTFE) by OH˙ was investigated using density functional theory (DFT). The potential energy surfaces were also defined in terms of single-point energies derived from the linked cluster CCSD(T) theory. With an energy barrier of -2.

Atmospheric degradation mechanism of anthracene initiated by OH: A DFT prediction.

Density functional theory (DFT) calculations at the M06-2X/def2-TZVP level have been employed to investigate the atmospheric oxidation mechanism of anthracene (ANT) initiated by HO. Direct hydrogen atom abstraction from the ANT using HO takes place hardly at ambient conditions while addition of HO to the C1, C2, and C4 sites are thermodynamically and kinetically more advantageous. The addition reactions are controlled by the aromaticity and the kinetic trends were justified by resonance stabilization energies.

Theoretical investigation on the mechanism and kinetics of the OH‒initiated atmospheric degradation of p-chloroaniline via OH‒addition and hydrogen abstraction pathways.

Atmospheric oxidative degradation of p-chloroaniline (PCA) initiated by OH has been studied theoretically at the M06-2X/aug-cc-pVTZ and CBS-QB3//M06-2X/aug-cc-pVTZ levels, coupled with kinetic calculations using the RRKM/ZCT method over the temperature range of 250-350 K. The calculations exhibit that the OH addition and hydrogen atom abstraction pathways are thermodynamically favorable. RRKM results revealed that the atmospheric oxidation of PCA is dominated by OH addition to the C1 and C2 atoms and hydrogen atom abstraction from amino group.

A comprehensive theoretical analysis of Curtius rearrangement of syn-syn and syn-anti conformers of oxalyl diazide.

The complete theoretical study of thermal Curtius rearrangement of syn-syn and syn-anti conformers of oxalyl diazide, in the gas phase and in solution has been established for the first time. The inexplicit solvent effect was taken into account via the self-consistent reaction field (SCRF) method. The gas and solution phases of all optimized geometries of the mentioned conformers associated with the Curtius rearrangement along the concerted and stepwise pathways were reported using the polarized continuum model and non-electrostatic terms from the SMD universal solvation model.

Closer Investigation of the Kinetics and Mechanism of Spirovinylcyclopropyl Oxindole Reaction with Σg-O by Topological Approaches and Unraveling the Role of the I Catalyst.

In this investigation at the MN15L/Def2-TZVP level of theory, we present computational evidence indicating that the reaction of Σg-O with spirovinylcyclopropyl oxindole () leads to a product called spiro-1,2-dioxolane () in its singlet state; this reaction occurs via a stepwise mechanism and its rate-determining step is catalyzed by iodine radicals, which promotes opening of the three-membered ring under dark conditions. The conversion of to 1-benzylindoline-2,3-dione () and 2-vinyloxirane () takes place via a concerted and slightly asynchronous reaction. Both electron localization function and AIM topological analysis reveal that the step associated with the attack of the Σg-O molecule on the intermediate characterizes the formation of the only new O-C single bond, which occurs in a stepwise mechanism, in contrast to the Δg-O reaction with species.

Unraveling the kinetics and molecular mechanism of gas phase pyrolysis of cubane to [8]annulene.

The kinetic and electron density flows are studied theoretically for the gas phase pyrolysis of cubane its cage opening to reach bicyclooctatriene and then thermal rearrangement of bicyclooctatriene to produce [8]annulene which is the experimentally observed major product. The observed kinetic data at the MN15-L/maug-cc-pVTZ level of theory were in good agreement with the experimental results as compared to the CBS-QB3 method. The cage opening and the thermal rearrangement steps at the experimentally employed temperature of 520 K were exergonic and exothermic.

Kinetic and mechanistic insight into the OH-initiated atmospheric oxidation of 2,3,7,8-tetrachlorodibenzo-p-dioxin via OH-addition and hydrogen abstraction pathways: A theoretical investigation.

The 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is the most toxic polychlorinated dibenzo-p-dioxin. The OH-initiated oxidation of TCDD has been studied using the density functional, canonical transition state, and canonical Rice-Ramsperger-Kassel-Marcus theories. The kinetic data were corrected for quantum tunneling by the Wigner and Eckart models.

Atmospheric oxidation reactions of imidazole initiated by hydroxyl radicals: kinetics and mechanism of reactions and atmospheric implications.

The atmospheric oxidation mechanism of imidazole initiated by hydroxyl radicals is investigated via OH-addition and H-abstraction pathways by quantum chemistry calculations at the M06-2X/aug-cc-pVTZ level of theory coupled with reaction kinetics calculations using statistical Rice-Ramsperger-Kassel-Marcus (RRKM) theory and transition state theory (TST). It was found that OH addition proceeds more rapidly than H-abstraction by several orders of magnitude. Moreover, H-abstraction reactions with submerged barriers exhibit positive temperature dependence.

Understanding the kinetics and molecular mechanism of unimolecular gas phase thermal decomposition of the α-ketoester methyl benzoylformate using RRKM and BET theories.

The RRKM calculation and bonding evolution theory analysis coupled with quantum theory of atoms in molecules have been used to investigate kinetics and molecular mechanism of gas phase thermal decomposition of methyl benzoylformate. The pressure-dependent rate coefficients, by applying different collisional efficiency values, indicated that the atmospheric pressure is in high-pressure limit of fall-off curve and low-pressure limit rate coefficients are in the range of 10-10 cm molec s. Temperature dependence of high-pressure limiting of rate coefficient over the temperature range 733 ± 20% K was estimated to be k=2.

Coronally advanced flap and connective tissue graft with or without plasma rich in growth factors (PRGF) in treatment of gingival recession.

Background: Several researchers have tried to improve the results of gingival recession treatment techniques. One of the methods is to use growth factors The present study was undertaken to evaluate the effect of CAF (coronally advanced flap) + CTG (connective tissue graft) + PRGF (plasma rich in growth factors) in the treatment of Miller Class I buccal gingival recession.

Material And Methods: Twenty-two teeth with Miller Class I gingival recession in 6 patients 26 ‒ 47 years of age were included in a split-mouth designed randomized controlled trial (RCT).

Guided tissue regeneration and platelet rich growth factor for the treatment of Grade II furcation defects: A randomized double-blinded clinical trial - A pilot study.

Background: The treatment of furcation area defects remained as a challenging issue in periodontal treatments. Regeneration treatment of furcation defects is the most discussed periodontal treatment. Although not completely hopeless in prognosis, the presence of the furcation involvement significantly increases the chance of tooth loss.

Following the Molecular Mechanism of Decarbonylation of Unsaturated Cyclic Ketones Using Bonding Evolution Theory Coupled with NCI Analysis.

The synergetic use of bonding evolution theory (BET) and noncovalent interaction (NCI) analysis allows to obtain new insight into the bond breaking/forming processes and electron redistribution along the reaction path to understand the molecular mechanism of a reaction and recognize regions of strong and weak electron pairing. This viewpoint has been considered for cheletropic extrusion of CO from unsaturated cyclic ketones cyclohepta-3,5-dien-1-one CHD, cyclopent-3-en-1-one CPE, and bicyclo[2.2.

The contrasting effect of the Ta/Nb ratio in (111)-layered B-site deficient hexagonal perovskite Ba5Nb4-xTaxO15 crystals on visible-light-induced photocatalytic water oxidation activity of their oxynitride derivatives.

The effect of the Ta/Nb ratio in the (111)-layered B-site deficient hexagonal perovskite Ba5Nb4-xTaxO15 (0 ≤ x ≤ 4) crystals grown by a KCl flux method on visible-light-induced photocatalytic water oxidation activity of their oxynitride derivatives BaNb1-xTaxO2N (0 ≤ x ≤ 1) was investigated. The Rietveld refinement of X-ray data revealed that all Ba5Nb4-xTaxO15 samples were well crystallized in the space group P3[combining macron]m1 (no. 164).

First-Principles Investigations of the Structure, Electronic, and Optical Properties of Mullite-Type Orthorhombic Bi2M4O9 (M = Al(3+), Ga(3+)).

The structure, electronic band structure, density of state, projected wave function, and optical properties of mullite-type orthorhombic Bi2M4O9 (M = Al(3+), Ga(3+)) crystals have been studied by applying density functional theory based on the Vanderbilt ultrasoft pseudopotential in the frame of the generalized gradient approximation as an exchange-correlation function. Satisfactory agreement between experimental and theoretical results indicates that the used method and conditions are suitable. M-O bonds in tetrahedral MO4 environments are stronger and more covalent with respect to octahedral MO6; also Bi-O bonds in both studied structures are almost ionic in nature.

Mechanism and regioselectivity of the reversible Diels-Alder cycloaddition of 2-methyl-1,3 butadiene with C48B6N6 heterofullerene: a DFT approach.

A theoretical study of the mechanism and regioslectivity of Diels-Alder [4+2] cycloaddition reactions between 2-methyl-1,3 butadiene and hetero bonds of the most stable isomer of C48B6N6 heterofullerene have been studied at the B3LYP/6-31G(*) level. Three heterobond pathways BC, BN and NC including two regioisomers for each one are considered by different approaches. All studied reactions have normal electron demand nature and corresponding regioisomers are produced via asynchronous processes.