1,158 research outputs found

    Cu-Mediated trifluoromethylation of benzyl, allyl and propargyl methanesulfonates with TMSCF 3

    Get PDF
    Abstract A Cu-mediated trifluoromethylation of benzyl, allyl and propargyl methanesulfonates with TMSCF 3 was developed for the first time. This method offers a convenient and economical approach to various trifluoroethyl-containing compounds. 286

    Clinical evaluation on the coaxial microincision cataract surgery in hard nuclear cataracts

    Get PDF
    AIM: To assess and compare the results of 2.2mm microincision coaxial cataract surgery(MCCS)phacoemulsification with the conventional 3.0mm MCCS in hard nuclear cataracts. METHODS: Totally 132 eyes with hard cataract(Ⅳ level and above)were randomized to two groups: 2.2mm MCCS(group 1:60 eyes)and 3.0mm MCCS(group 2:72 eyes). All patients underwent standard phacoemulsification and intraocular lens implantation surgery by one experienced surgeon. The average ultrasound power(AVE)was recorded during the operation. The incidences of capsule rupture and postoperative corneal edema were compared.Visual acuity, surgically induced astigmatism(SIA)and the descent rate of endothelial cell density were compared at intervals of 1 day, 1 month and 3 months after surgery. Statistic analysis was taken by Student's t test and Chi square test. RESULTS: There was no significant difference on the incidences of capsule rupture, postoperative corneal edema and AVE(P> 0.05)between the two groups(3.3%, 10.0%, 65.09±20.15)and(4.2%, 11.1%, 69.13±15.44). One day after the surgery, the 2.2mm MCCS group showed better uncorrected visual acuity as compared to the 3.0mm MCCS group(P < 0.05). There were no significant differences on best-corrected visual acuity on 1 month and 3 months after the surgery. There was no significant difference on the descent rate of endothelial cell density(16.54%±10.20%, 17.69%±10.65%)3 months after the surgery. One day, 1 month and 3 months after the surgery, SIA was 0.77±0.31,0.66±0.29, 0.52±0.25D in the 2.2mm MCCS group, and 1.41±0.73,0.98±0.61D,0.82±0.35D in the 3.0mm MCCS group, respectively. The differences were statistically significant. CONCLUSION: The operative safety of the 2.2mm MCCS group were the same as 3.0mm MCCS group with the hard nuclear cataracts. The 2.2mm MCCS phacoemulsification could significantly reduce SIA and get better earlier visual rehabilitation

    2-Chloro-5-(chloro­meth­yl)pyridine

    Get PDF
    The title compound, C6H5Cl2N, is almost planar, with an r.m.s. deviation of 0.0146 Å for all atoms except for the 5-choloromethyl Cl atom. The offset Cl atom lies above this plane with a Cl—C—C angle of 111.11 (17)°. In the crystal, mol­ecules are connected via inter­molecular C—H⋯N hydrogen bonds, forming dimers

    catena-Poly[[{2-[(2-hy­droxy­eth­yl)imino­meth­yl]-6-meth­oxy­phenolato}copper(II)]-μ-thio­cyanato]

    Get PDF
    In the title thio­cyanate-bridged polynuclear copper(II) complex, [Cu(C10H12NO3)(NCS)]n, the Cu atom is five-coordinated in a square-pyramidal geometry, with one phenolato O, one imino N and one hy­droxy O atom of a Schiff base ligand and one thio­cyanato N atom defining the basal plane, and with one thio­cyanato S atom occupying the apical position. In the crystal structure, pairs of adjacent complex mol­ecules are linked through inter­molecular O—H⋯O hydrogen bonds into dimers. The dimers are further linked via Cu⋯S inter­actions, forming two-dimensional layers parallel to the bc plane

    Generic phylogeny, historical biogeography and character evolution of the cosmopolitan aquatic plant family Hydrocharitaceae

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Hydrocharitaceae is a fully aquatic monocot family, consists of 18 genera with approximately 120 species. The family includes both fresh and marine aquatics and exhibits great diversity in form and habit including annual and perennial life histories; submersed, partially submersed and floating leaf habits and linear to orbicular leaf shapes. The family has a cosmopolitan distribution and is well represented in the Tertiary fossil record in Europe. At present, the historical biogeography of the family is not well understood and the generic relationships remain controversial. In this study we investigated the phylogeny and biogeography of Hydrocharitaceae by integrating fossils and DNA sequences from eight genes. We also conducted ancestral state reconstruction for three morphological characters.</p> <p>Results</p> <p>Phylogenetic analyses produced a phylogeny with most branches strongly supported by bootstrap values greater than 95 and Bayesian posterior probability values of 1.0. <it>Stratiotes </it>is the first diverging lineage with the remaining genera in two clades, one clade consists of <it>Lagarosiphon, Ottelia, Blyxa, Apalanthe, Elodea </it>and <it>Egeria</it>; and the other consists of <it>Hydrocharis</it>-<it>Limnobium, Thalassia, Enhalus, Halophila, Najas, Hydrilla, Vallisneria, Nechamandra </it>and <it>Maidenia</it>. Biogeographic analyses (DIVA, Mesquite) and divergence time estimates (BEAST) resolved the most recent common ancestor of Hydrocharitaceae as being in Asia during the Late Cretaceous and Palaeocene (54.7-72.6 Ma). Dispersals (including long-distance dispersal and migrations through Tethys seaway and land bridges) probably played major roles in the intercontinental distribution of this family. Ancestral state reconstruction suggested that in Hydrocharitaceae evolution of dioecy is bidirectional, viz., from dioecy to hermaphroditism, and from hermaphroditism to dioecy, and that the aerial-submerged leaf habit and short-linear leaf shape are the ancestral states.</p> <p>Conclusions</p> <p>Our study has shed light on the previously controversial generic phylogeny of Hydrocharitaceae. The study has resolved the historical biogeography of this family and supported dispersal as the most likely explanation for the intercontinental distribution. We have also provided valuable information for understanding the evolution of breeding system and leaf phenotype in aquatic monocots.</p
    corecore