Search results for "orbit"
showing 10 items of 1104 documents
The role of SAXS and molecular simulations in 3D structure elucidation of a DNA aptamer against lung cancer
2021
Aptamers are short, single-stranded DNA or RNA oligonucleotide molecules that function as synthetic analogs of antibodies and bind to a target molecule with high specificity. Aptamer affinity entirely depends on its tertiary structure and charge distribution. Therefore, length and structure optimization are essential for increasing aptamer specificity and affinity. Here, we present a general optimization procedure for finding the most populated atomistic structures of DNA aptamers. Based on the existed aptamer LC-18 for lung adenocarcinoma, a new truncated LC-18 (LC-18t) aptamer LC-18t was developed. A three-dimensional (3D) shape of LC-18t was reported based on small-angle X-ray scattering…
Structure‐ and Interaction‐Based Design of Anti‐SARS‐CoV‐2 Aptamers
2022
Aptamer selection against novel infections is a complicated and time-consuming approach. Synergy can be achieved by using computational methods together with experimental procedures. This study aims to develop a reliable methodology for a rational aptamer in silico et vitro design. The new approach combines multiple steps: (1) Molecular design, based on screening in a DNA aptamer library and directed mutagenesis to fit the protein tertiary structure; (2) 3D molecular modeling of the target; (3) Molecular docking of an aptamer with the protein; (4) Molecular dynamics (MD) simulations of the complexes; (5) Quantum-mechanical (QM) evaluation of the interactions between aptamer and target with …
Silver Sulfide Nanoclusters and the Superatom Model
2015
The superatom model of electron-shell closings has been widely used to explain the stability of noble-metal nanoclusters of few nanometers, including thiolate-protected Au and Ag nanoclusters. The presence of core sulfur atoms in silver sulfide (Ag–S) nanoclusters renders them a class of clusters with distinctive properties as compared to typical noble-metal clusters. Here, it is natural to ask whether the superatom model is still applicable for the Ag–S nanoclusters with mixed metal and nonmetal core atoms. To address this question, we applied density functional simulations to analyze a series of Ag–S nanoclusters: Ag14S(SPh)12(PPh3)8, Ag14(SC6H3F2)12(PPh3)8, Ag70S16(SPh)34(PhCO2)4(triphos…
Prawo kosmiczne w kontekście trzech reżimów prawnych. Jedność celów czy egoizm interesów?
2021
W artykule zaprezentowano aktualne kwestie związane z wykorzystaniem przestrzeni kosmicznej wraz ze wskazaniem konieczności przestrzegania obowiązujących regulacji, współtworzących międzynarodowe prawo kosmiczne. Zaprezentowano swego rodzaju proces ‒ ewolucję wykorzystywania przestrzeni kosmicznej, począwszy od monopolu państw, przez zdefiniowane wolą państw działania organizacji międzynarodowych, kończąc na narodowych agencjach kosmicznych, będących instytucjonalnym wsparciem również dla prywatnych podmiotów. W pracy, adekwatnie do wykazanej wielopodmiotowości, prezentuje się regulacje prawne, w których pierwsze konwencje, umowy z lat 60. i 70. XX w., współtworzące międzynarodowe prawo kos…
Análisis de antibióticos en alimentos de origen animal, agua de bebida para animales y piensos por cromatografía líquida de alta resolución acoplada …
2022
La utilización de agentes antimicrobianos en producción animal es uno de los principales riesgos para la salud debido a su potencial presencia como residuos en los alimentos en cualquier etapa de la cadena alimentaria. Según datos de la Agencia Europea de Medicamento, España es uno de los países en que las ventas de agentes antimicrobianos para animales productores de alimentos son más elevadas. Los principales efectos adversos producidos por los antibióticos son reacciones alérgicas, destrucción de la microbiota presente en el tracto gastrointestinal y el aumento de la selectividad de bacterias multiresistentes o producción de resistencias antimicrobianas. Actualmente, la resistencia a los…
Theoretical and computational studies of magnetic anisotropy and exchange coupling in molecular systems
2018
The field of molecular magnetism studies the magnetic properties of molecular systems as opposed to conventional metal-based magnets. The high chemical modifiability of the constituting molecules makes such materials highly versatile, and the small size of the building blocks leads to the rise of various quantum mechanical phenomena, such as tunneling and entanglement. These phenomena can then be further utilized in the construction of nanoscale quantum devices. This dissertation describes computational and theoretical studies in the field of molecular magnetism using state-of-the-art quantum chemical methods based on ab initio multireference approaches and broken symmetry density functional t…
L'ERNIAZIONE DELLE GHIANDOLE LACRIMALI IN PAZIENTI CON OFTALMOPATIA DI GRAVES: UN POSSIBILE MARKER DI ATTIVITÀ DELLA MALATTIA.
2018
Scopo Il coinvolgimento delle ghiandole lacrimali (GL) in pazienti affetti da Oftalmopatia di Graves (OG) è stato considerato come una potenziale causa dei sintomi tipicamente associati a questa malattia. Diversi studi hanno rilevato che le dimensioni delle GL nei pazienti OG sono aumentate, ma non ci sono studi che prendono in considerazione pazienti con diversa attività della malattia. Abbiamo valutato l'erniazione delle GL rilevata sulle immagini di risonanza magnetica (RM), in pazienti con diversa attività OG. Materiale e metodi Trentadue pazienti (10M, 22F, età media 49,5 anni, range 30-68) con OG sono stati arruolati e raggruppati in base all'attività della malattia (A: n = 16 co…
Localized surface plasmon resonance in silver nanoparticles: Atomistic first-principles time-dependent density-functional theory calculations
2015
We observe using ab initio methods that localized surface plasmon resonances in icosahedral silver nanoparticles enter the asymptotic region already between diameters of 1 and 2 nm, converging close to the classical quasistatic limit around 3.4 eV. We base the observation on time-dependent density-functional theory simulations of the icosahedral silver clusters Ag$_{55}$ (1.06 nm), Ag$_{147}$ (1.60 nm), Ag$_{309}$ (2.14 nm), and Ag$_{561}$ (2.68 nm). The simulation method combines the adiabatic GLLB-SC exchange-correlation functional with real time propagation in an atomic orbital basis set using the projector-augmented wave method. The method has been implemented for the electron structure…
Strength of J(pi)=1(+) Gamow-Teller and isovector spin monopole transitions in double-beta-decay triplets
2014
In this work we study systematically the energetics and intensity distributions of Gamow-Teller (GT ± )and isovector spin monopole (IVSM ± ) transitions from the ground states of the pairs ( 76 Ge, 76 Se), ( 82 Se, 82 Kr), ( 100 Mo, 100 Ru), ( 116 Cd, 116 Sn), ( 128 Te, 128 Xe), ( 130 Te, 130 Xe), and ( 136 Xe, 136 Ba), of double-beta-decay initial and final nuclei, to the J π = 1 + excited states of the intermediate odd-odd nuclei 76 As, 82 Br, 100 Tc, 116 In, 128 , 130 I, and 136 Cs. We use a proton-neutron quasiparticle random-phase approximation (QRPA) theory framework with the Bonn-A two-body interaction in large no-core single-particle valence bases. Our studies indicate that the GT −…
On-Orbit Degradation of Solar Instruments
2013
International audience; We present the lessons learned about the degradation observed in several space solar missions, based on contributions at the Workshop about On-Orbit Degradation of Solar and Space Weather Instruments that took place at the Solar Terrestrial Centre of Excellence (Royal Observatory of Belgium) in Brussels on 3 May 2012. The aim of this workshop was to open discussions related to the degradation observed in Sun-observing instruments exposed to the effects of the space environment. This article summarizes the various lessons learned and offers recommendations to reduce or correct expected degradation with the goal of increasing the useful lifespan of future and ongoing s…