Search results for " ring"
showing 10 items of 478 documents
Crystal structure and Hirshfeld surface analysis of (E)-3-[(4-fluorobenzylidene)amino]-5-phenylthiazolidin-2-iminium bromide
2019
TARAMAPUBMED TARAMASCOPUS TARAMAWOS In the cation of the title salt, C16H15FN3S+·Br−, the phenyl ring is disordered over two sets of sites with a refined occupancy ratio of 0.503 (4):0.497 (4). The mean plane of the thiazolidine ring makes dihedral angles of 13.51 (14), 48.6 (3) and 76.5 (3)° with the fluorophenyl ring and the major- and minor-disorder components of the phenyl ring, respectively. The central thiazolidine ring adopts an envelope conformation. In the crystal, centrosymmetrically related cations and anions are linked into dimeric units via N—H...Br hydrogen bonds, which are further connected by weak C—H...Br hydrogen bonds into chains parallel to [110]. Hirshfeld surface an…
rac-11-Selena-12,13-diazabicyclo[10.3.0]pentadeca-10a(13a),12-dien-1-ol
2021
The title compound, C12H20N2OSe, crystallizes in strands of enantiomeric molecules connected via O—H...N hydrogen bonds. There are only slight deviations from an ideal gauche conformation in the decamethylene chain, indicating just a little strain.
rac-12-Selena-13,14-diazatricyclo[9.3.0.02,4]tetradeca-11,13-diene
2020
The centrosymmetric crystal structure of the title compound, C11H16N2Se, is built up from alternating strands of (R,R)- and (S,S)-enantiomers. These strands, which propagate along the c-axis direction, are composed of homochiral molecules related to each other by twofold screw axes. The shape of the molecule is an almost planar unit around the selenadiazole ring with a hexamethylene chain as an arched handle.
Genetic variability and evolutionary dynamics of tomato black ring virus population
2021
Tomato black ring virus (TBRV) is an important pathogen infecting a wide range of plant species worldwide. Phylogenetic studies of TBRV have already been conducted, although limited by the use of short genomic regions or a reduced amount of isolates. In the present study, we carried out an exhaustive phylogenetic and population genetic analysis based on the coat protein gene (CP) sequence of 57 TBRV isolates originating from different host plants and European geographic regions (47 isolates from Poland, 8 from Lithuania, one from the UK, and one from Hungary). Moreover, the selective pressure acting on particular codons and coevolution of amino acid residues in the CP were analysed. The res…
The Large Hadron–Electron Collider at the HL-LHC
2021
The Large Hadron-Electron Collider (LHeC) is designed to move the field of deep inelastic scattering (DIS) to the energy and intensity frontier of particle physics. Exploiting energy-recovery technology, it collides a novel, intense electron beam with a proton or ion beam from the High-Luminosity Large Hadron Collider (HL-LHC). The accelerator and interaction region are designed for concurrent electron-proton and proton-proton operations. This report represents an update to the LHeC's conceptual design report (CDR), published in 2012. It comprises new results on the parton structure of the proton and heavier nuclei, QCD dynamics, and electroweak and top-quark physics. It is shown how the LH…
Evaluation of a new nomogram for Ferrara ring segment implantation in keratoconus
2021
AIM: To evaluate the short-term clinical outcomes of Ferrara rings in keratoconus using an optimized nomogram developed after several years of research and retrospective analysis of clinical data. METHODS: This prospective longitudinal non-comparative clinical trial evaluated 88 eyes of 88 patients (age 18-62y) with keratoconus diagnosis from two Spanish centers. Ferrara ring segment (AJL Ophthalmic) implantation was performed in all cases, using the mechanical procedure in 25 eyes (28.4%) and a femtosecond laser-assisted procedure in 63 eyes (71.6%). The ring segments implanted in each case were selected using a new optimized nomogram that considered variables such as anterior corneal asph…
A comparison between the single ring pressure infiltrometer and simplified falling head techniques
2013
Testing the relative performances of the single ring pressure infiltrometer (PI) and simplified falling head (SFH) techniques to determine the field saturated soil hydraulic conductivity, Kfs, at the near point scale may help to better establish the usability of these techniques for interpreting and simulating hydrological processes. A sampling of 10 Sicilian sites showed that the measured Kfs was generally higher with the SFH technique than the PI one, with statistically significant differences by a factor varying from 3 to 192, depending on the site. A short experiment with the SFH technique yielded higher Kfs values because a longer experiment with the PI probably promoted short-term swe…
One-pot synthesis of fluorinated 2-amino-pyrimidine-N-oxides. Competing pathways in the four-atom side-chain rearrangements of 1,2,4-oxadiazoles
2006
Abstract Trifluoromethylated 2-amino-pyrimidine N-oxides have been synthesized by reaction of the 3-amino-5-methyl-1,2,4-oxadiazole with trifluoromethyl-β-diketones in the presence of perchloric acid, followed by hydrolysis. In this ring-to-ring transformation an initial formation of (unisolated) 1,2,4-oxadiazole-pyrimidinium salts, and subsequent ring-opening at the oxadiazole moiety occurs. Isolation of 2-(hydroxyamino)-pyrimidine from the reaction mixture evidenced the presence of a competing pathway where the N(4) nitrogen of the oxadiazole is involved in the formation of a regioisomeric pyrimidinium salt. The effect of the trifluoromethyl group on the product distribution is discussed.…