Search results for "MOLECULE"

Orientation Adaptive Minimal Learning Machine for Directions of Atomic Forces

2021

Machine learning (ML) force fields are one of the most common applications of ML in nanoscience. However, commonly these methods are trained on potential energies of atomic systems and force vectors are omitted. Here we present a ML framework, which tackles the greatest difficulty on using forces in ML: accurate prediction of force direction. We use the idea of Minimal Learning Machine to device a method which can adapt to the orientation of an atomic environment to estimate the directions of force vectors. The method was tested with linear alkane molecules. peerReviewed

Modelling the effect of nuclear motion on the attosecond time-resolved photoelectron spectra of ethylene

2014

arXiv:1403.5408

Proton‐Gated Ring‐Closure of a Negative Photochromic Azulene‐Based Diarylethene

2020

Abstract Proton‐responsive photochromic molecules are attractive for their ability to react on non‐invasive rapid optical stimuli and the importance of protonation/deprotonation processes in various fields. Conventionally, their acidic/basic sites are on hetero‐atoms, which are orthogonal to the photo‐active π‐center. Here, we incorporate azulene, an acid‐sensitive pure hydrocarbon, into the skeleton of a diarylethene‐type photoswitch. The latter exhibits a novel proton‐gated negative photochromic ring‐closure and its optical response upon protonation in both open and closed forms is much more pronounced than those of diarylethene photoswitches with hetero‐atom based acidic/basic moieties. …

Anti-oxidant and anti-inflammatory properties of betalains from Cactus Pear

2004

Anti-oxidant and anti-inflammatory properties of Betalains from Cactus Pear. C. Gentile1, A. Marconi1, M. A. Livrea2, G. Uzan1, P. D’Alessio1. 1 Inserm U602, Paris, France. 2 Dip. Farmacochimico, Tossicologico e Biologico, Università Palermo, Italy. Betalains of phytochemical origin, known as potent radical-scavengers in chemical and biological systems, have been tested in a model of inflammation. New phytochemicals are continuously inspected for potential pharmacological applications. The red betanin and the yellow indicaxanthin have recently been isolated and characterized from Cactus Pear. Reactive Oxygen Species may be toxic or display a regulatory character. During the inflammation rea…

Bioactive molecules from soil and marine bacteria: new potential applications

2015

Biological activities of the extracts from macroalgae Carpodesmia crinita, Carpodesmia brachycarpa, Asparagopsis taxiformis

2023

Marine species represent a rich source of biologically active products that can be used in various fields. Among them, marine algae produce numerous secondary metabolites responsible for different biological activities such as: immunomodulatory [1], antioxidant [2], and antimicrobial [3]. The aim of this study was chemically characterizing the extracts of three macroalgae species: Carpodesmia crinite (Duby) Orellana & Sansón, 2019, Carpodesmia brachycarpa (J. Agardh) Orellana & Sansón 2019, Asparagopsis taxiformis (Delile) Trevisan 1845 and evaluate their biological activities. The characterization of the secondary metabolites was performed by HPLC-MS and the results obtained showed…

ANTIMICROBIAL ACTIVITY FROM POLYPEPTIDE-RICH EXTRACTS OF THE SEAGRASS POSIDONIA OCEANICA

2021

The present study was carried out to assess the antibacterial, antifungal and antibiofilm properties of polypeptide-rich extracts isolated from green leaves and rhizomes of Mediterranean seagrass Posidonia oceanica (L. Delile) (Posidoniaceae). The seagrass was collected, washed with freshwater, grinded with liquid nitrogen in order to obtain fine powders that were exposed to extraction by acetic acid and antiproteases. The crude extracts isolated from leaves and rhizomes of P. oceanica were subjected to microbiological assays to evaluate the antibacterial, antifungal and antibiofilm activity of polypeptide fraction against two reference bacterial strains Staphylococcus aureus ATCC 25923 and…

Biotecnology and Cultural Heritage: bioactive molecules applied in restoration projects

2014

Influence of bacterial physiology on processing of selenite, biogenesis of nanomaterials and their thermodynamic stability

2019

We explored how Ochrobactrum sp. MPV1 can convert up to 2.5 mM selenite within 120 h, surviving the challenge posed by high oxyanion concentrations. The data show that thiol-based biotic chemical reaction(s) occur upon bacterial exposure to low selenite concentrations, whereas enzymatic systems account for oxyanion removal when 2 mM oxyanion is exceeded. The selenite bioprocessing produces selenium nanomaterials, whose size and morphology depend on the bacterial physiology. Selenium nanoparticles were always produced by MPV1 cells, featuring an average diameter ranging between 90 and 140 nm, which we conclude constitutes the thermodynamic stability range for these nanostructures. Alternativ…

New Multidimensional Coordination Polymers with μ 2 ‐ and μ 3 ‐dcno Cyano Carbanion Ligand {dcno – = [(NC) 2 CC(O)O(CH 2 ) 2 OH] – }

2006

New polymeric materials [M(dcno)2(H2O)2] [M = FeII (1), CoII (2)] and [M(dcno)2] [M = CuII (3), MnII (4)] with dcno– =[(NC)2CC(O)O(CH2)2OH]– = 2,2-dicyano-1-(2-hydroxyethoxy)ethenolate anion have been synthesised and characterised by IR spectroscopy, X-ray crystallography and magnetic measurements. In compounds 1 and 2, each organic ligand acts in a bridging mode with its two nitrogen atoms bound to two different metal ions, while in compounds 3 and 4, each organic anion acts as a μ3-bridging ligand through its two nitrogen atoms and the oxygen atom of the OH group. Each metal ion has a pseudo-octahedral trans-MN4O2 environment with four nitrogen atoms from four different organic ligands an…