scholarly journals Nearly free surface silanols are the critical molecular moieties that initiate the toxicity of silica particles

2020 ◽  
Vol 117 (45) ◽  
pp. 27836-27846 ◽  
Author(s):  
Cristina Pavan ◽  
Rosangela Santalucia ◽  
Riccardo Leinardi ◽  
Marco Fabbiani ◽  
Yousof Yakoub ◽  
...  
Keyword(s):  
Density Functional ◽  
Ad Hoc ◽  
Density Functional Theory Calculations ◽  
Silica Particles ◽  
Functional Theory ◽  
Preparation Methods ◽  
Toxic Activity ◽  
Proinflammatory Activity ◽  
Membrane Components

Inhalation of silica particles can induce inflammatory lung reactions that lead to silicosis and/or lung cancer when the particles are biopersistent. This toxic activity of silica dusts is extremely variable depending on their source and preparation methods. The exact molecular moiety that explains and predicts this variable toxicity of silica remains elusive. Here, we have identified a unique subfamily of silanols as the major determinant of silica particle toxicity. This population of “nearly free silanols” (NFS) appears on the surface of quartz particles upon fracture and can be modulated by thermal treatments. Density functional theory calculations indicates that NFS locate at an intersilanol distance of 4.00 to 6.00 Å and form weak mutual interactions. Thus, NFS could act as an energetically favorable moiety at the surface of silica for establishing interactions with cell membrane components to initiate toxicity. With ad hoc prepared model quartz particles enriched or depleted in NFS, we demonstrate that NFS drive toxicity, including membranolysis, in vitro proinflammatory activity, and lung inflammation. The toxic activity of NFS is confirmed with pyrogenic and vitreous amorphous silica particles, and industrial quartz samples with noncontrolled surfaces. Our results identify the missing key molecular moieties of the silica surface that initiate interactions with cell membranes, leading to pathological outcomes. NFS may explain other important interfacial processes involving silica particles.

scholarly journals Structural and electronic determinants of flavonoid binding to human serum albumin: an extensive ligand-based study

RSC Advances ◽  
2016 ◽  
Vol 6 (79) ◽  
pp. 75014-75022 ◽  
Author(s):  
Hrvoje Rimac ◽  
Željko Debeljak ◽  
Davor Šakić ◽  
Tin Weitner ◽  
Mario Gabričević ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Human Serum Albumin ◽  
Serum Albumin ◽  
Human Serum ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Functional Theory ◽  
Flavonoid Aglycones ◽  
Fluorescence Measurements

The most prominent features responsible for binding of flavonoid aglycones to the IIA region of human serum albumin (HSA) were determined based onin vitrofluorescence measurements and density functional theory calculations.

scholarly journals Design, synthesis, crystal structure, in vitro cytotoxicity evaluation, density functional theory calculations and docking studies of 2-(benzamido) benzohydrazide derivatives as potent AChE and BChE inhibitors

RSC Advances ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 154-167
Author(s):  
Naghmana Kausar ◽  
Shahzad Murtaza ◽  
Muhammad Nadeem Arshad ◽  
Rahman Shah Zaib Saleem ◽  
Abdullah M. Asiri ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Density Functional Theory ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Docking Studies ◽  
In Vitro Cytotoxicity ◽  
Methyl Anthranilate ◽  
Functional Theory ◽  
Design Synthesis

2-(Benzamido) benzohydrazide derivatives: synthesis from methyl anthranilate and application as potent anti-Alzheimer's agents.

The structures of xenorine A–C from the entomopathogenic bacterium Xenorhabdus indica

2017 ◽  
Vol 41 (5) ◽  
pp. 262-265
Author(s):  
Lie-Feng Ma ◽  
Hao-Ying Qian ◽  
Yang Zheng ◽  
Wei-Wei Pang ◽  
Yuan-Yuan Li ◽  
...  
Keyword(s):  
Quantum Chemical ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
2D Nmr ◽  
Immunosuppressive Activity ◽  
Functional Theory ◽  
Chemical Structures ◽  
Synthetic Product ◽  
New Compounds

Three new compounds, xenorine A-C, along with six known compounds were isolated from the cultured broth of Xenorhabdus indica. The chemical structures of these compounds were elucidated mainly by analysis of 1D and 2D NMR and MS data. The major metabolites were dioxopiperazines. In addition, 5,6,11,11a-tetrahydro-1 H-imidazo[1′,5′:1,6]pyrido[3,4- b]indole-1,3(2 H)-dione, previously described as synthetic product, was isolated as a natural product. The absolute configuration was determined using quantum chemical time-dependent density functional theory calculations. The six known compounds showed weak in vitro immunosuppressive activity towards concanavalin-A- and lipopolysaccharide -induced proliferation of mice splenocytes.

On the Linear Geometry of Lanthanide Hydroxide (Ln—OH, Ln=La-Lu)

2019 ◽  
Author(s):  
Hassan Harb ◽  
Lee Thompson ◽  
Hrant Hratchian
Keyword(s):  
Triple Bond ◽  
Density Functional ◽  
Valence Electron ◽  
Density Functional Theory Calculations ◽  
Electron Configuration ◽  
Functional Theory ◽  
Key Species ◽  
Pi Orbitals ◽  
Lanthanide Hydroxide ◽  
Linear Geometry

Lanthanide hydroxides are key species in a variety of catalytic processes and in the preparation of corresponding oxides. This work explores the fundamental structure and bonding of the simplest lanthanide hydroxide, LnOH (Ln=La-Lu), using density functional theory calculations. Interestingly, the calculations predict that all structures of this series will be linear. Furthermore, these results indicate a valence electron configuration featuring an occupied sigma orbital and two occupied pi orbitals for all LnOH compounds, suggesting that the lanthanide-hydroxide bond is best characterized as a covalent triple bond.

On the Linear Geometry of Lanthanide Hydroxide (Ln—OH, Ln=La-Lu)

2019 ◽  
Author(s):  
Hassan Harb ◽  
Lee Thompson ◽  
Hrant Hratchian
Keyword(s):  
Triple Bond ◽  
Density Functional ◽  
Valence Electron ◽  
Density Functional Theory Calculations ◽  
Electron Configuration ◽  
Functional Theory ◽  
Key Species ◽  
Pi Orbitals ◽  
Lanthanide Hydroxide ◽  
Linear Geometry

Lanthanide hydroxides are key species in a variety of catalytic processes and in the preparation of corresponding oxides. This work explores the fundamental structure and bonding of the simplest lanthanide hydroxide, LnOH (Ln=La-Lu), using density functional theory calculations. Interestingly, the calculations predict that all structures of this series will be linear. Furthermore, these results indicate a valence electron configuration featuring an occupied sigma orbital and two occupied pi orbitals for all LnOH compounds, suggesting that the lanthanide-hydroxide bond is best characterized as a covalent triple bond.

A New Interpretation of the Structure and Solvent Dependence of the Far UV Circular Dichroism Spectrum of Short Oligopeptides

2019 ◽  
Author(s):  
Anshuman Kumar ◽  
Reinhard Schweitzer-Stenner ◽  
Bryan Wong
Keyword(s):  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Cd Spectra ◽  
Functional Theory ◽  
Polyproline Ii ◽  
Solvent Dependence ◽  
Explicit Consideration ◽  
New Interpretation ◽  
Implicit And Explicit ◽  
Explicit Water

In this work, we carry out new time-dependent density functional theory calculations on the cationic tripeptide GAG in implicit and explicit water to determine the transitions that give rise to the observed CD signals of polyproline II and β-strand conformations. Our results reveal a plethora of electronic transitions that are governed by configurational interactions between multiple molecular orbital transitions of comparable energy. We also show that reproducing the CD spectra of polyproline II and β-strand conformations requires the explicit consideration of water molecules. The structure dependence of delocalized occupied orbitals contributes to the experimentally-observed invalidation of Flory’s isolated pair hypothesis.

A New Interpretation of the Structure and Solvent Dependence of the Far UV Circular Dichroism Spectrum of Short Oligopeptides

2019 ◽  
Author(s):  
Anshuman Kumar ◽  
Reinhard Schweitzer-Stenner ◽  
Bryan Wong
Keyword(s):  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Cd Spectra ◽  
Functional Theory ◽  
Polyproline Ii ◽  
Solvent Dependence ◽  
Explicit Consideration ◽  
New Interpretation ◽  
Implicit And Explicit ◽  
Explicit Water

In this work, we carry out new time-dependent density functional theory calculations on the cationic tripeptide GAG in implicit and explicit water to determine the transitions that give rise to the observed CD signals of polyproline II and β-strand conformations. Our results reveal a plethora of electronic transitions that are governed by configurational interactions between multiple molecular orbital transitions of comparable energy. We also show that reproducing the CD spectra of polyproline II and β-strand conformations requires the explicit consideration of water molecules. The structure dependence of delocalized occupied orbitals contributes to the experimentally-observed invalidation of Flory’s isolated pair hypothesis.

Is a Non-Transition Element Nitride Ferromagnet Ever Achievable? Indication of the N-N Pairing Instability

2006 ◽  
Vol 71 (11-12) ◽  
pp. 1525-1531 ◽  
Author(s):  
Wojciech Grochala
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Transition Element ◽  
Density Functional Theory Calculations ◽  
Functional Theory

The enthalpy of four polymorphs of CaN has been scrutinized at 0 and 100 GPa using density functional theory calculations. It is shown that structures of diamagnetic calcium diazenide (Ca2N2) are preferred over the cubic ferromagnetic polymorph (CaN) postulated before, both at 0 and 100 GPa.

Sign in / Sign up

Export Citation Format

Share Document