Anatomical Variations of the Vertebral Artery: Analysis by Three-Dimensional Computed Tomography Angiography in Chinese Population.

OBJECTIVE: To analyze the anatomical variations of V3 and V2 segments of the vertebral artery in the Chinese population. METHODS: The current retrospective study was an observational, anatomical, radiological research. Between 1 January 2018 to 31 December 2019, the data of 589 continuous head-and-neck three-dimensional computed tomography angiography were observed and analyzed using the open-source software of Horos. There were 415 males and 174 females with an average age of 44.63 ± 2.5(18-74) years. The variations of the V3 segment were defined as persistent first intersegmental artery (PFIA) and paracondylar processes (PP). The variations of V2 segments were unusual vertebral artery entrance transverse foreman (UE-V2S) and midline migration (MM). The incidences of all variations were summarized and the gender, side characters were compared. RESULTS: Among the patients, 4.34% (18/415) males and 4.60% (8/174) females were with the variation of PFIA. Meanwhile, 12.29% (51/415) males and 10.92% (19/174) females were with the variation of PP. Then 18.80% (78/415) males and 16.67% (29/174) females were with UE-V2S. All the variations above were not different in genders. As for the variation of MM, 3.86% (16/415) males and 8.62% (15/174) females were identified, and the difference of genders was significant for this type of variation (P < 0.05). The differences between each side were also observed and analyzed for all variations and no differences were found. CONCLUSION: There are several variations of V3 and V2 segments of the vertebral artery are associated with the cervical surgeries, most were without differences in genders and sides, except the variation of MM.

Synthesis and characterization of mixed-valence manganese fluorophosphate and analogues with clathrate-like structures: Mn(III)6F12(PO3(OH))8[Na8(Kx(H3O)4-x(H2O)2)M(IV)(OH)6] (M(IV) = Mn, Ti, Ge).

A novel, mixed- and high-valence manganese (Mn(3+)/Mn(4+)) fluorophosphate, Mn(III)6F12(PO3(OH))8[Na8(Kx(H3O)4-x(H2O)2)Mn(IV)(OH)6] (denoted as MN), has been prepared via a water-deficient hydrothermal route with phosphoric acid as the sole solvent. This compound features a cubic three-dimensional open-framework structure built from corner-sharing [Mn(III)O4F2] octahedra and [HPO4] groups, which encapsulates a clathrate-like "guest cluster" of Na8(Kx(H3O)4-x(H2O)2)Mn(IV)(OH)6. The guest cluster is architecturally composed of a [Mn(IV)(OH)6] octahedron in a cubic cage of Na(+) cations, which in turn is surrounded by an octahedral arrangement of K(+)/H2O ions, resulting in an unprecedented octahedral @ cubic @ octahedral @ cubic arrangement (OCOC). The +4 oxidation state of Mn in the guest cluster has been confirmed by the synthesis of isotypic Ti- and Ge- analogues (denoted as TI and GE) using TiO2 and GeO2 as the replacement for MnO2 in the starting materials. The compounds MN, TI and GE are not stable in aqueous solution and are peeled off layer-by-layer after the absorption of water. This report provides a new route for the synthesis of mixed- and high-valence manganese phosphates that cannot be produced by conventional hydrothermal methods.

Analysis of caffeic acid derivatives from Osmanthus yunnanensis using electrospray ionization quadrupole time-of-flight mass spectrometry.

A series of six caffeic acid derivatives (1-6) in Osmanthus yunnanensis were investigated by electrospray quadrupole time-of-flight tandem mass spectrometry (ESI-QToF-MS/MS) in both negative- and positive-ion modes. High-quality MS/MS spectra of [M + H](+) are generated from high-abundance protonated parent ions obtained by addition of ammonium chloride to the solutions. Fragmentation mechanisms of [M - H](-) and [M + H](+) precursor ions were proposed and elemental compositions of most of the product ions were confirmed on the basis of the high-resolution ESI-collision-induced dissociation (CID)- MS/MS spectra. It was found that the fragment ions at m/z 179, m/z 161, m/z 135 and m/z 134 in negative-ion mode and at m/z 163, m/z 145 and m/z 135 in positive mode should be the characteristic ions of caffeic acid. In addition, the radical fragment ions with high abundance were observed for many caffeic acid derivatives especially for 4. The structural elements of unknown compounds 7 and 8 were tentatively identified on based on tandem mass spectra of known ones.

Analysis of epipolythiodioxopiperazines in fungus Chaetomium cochliodes using HPLC-ESI-MS/MS/MS.

A series of epipolythiodioxopiperazines in the fungus Chaetomium cochliodes was investigated using reversed-phase liquid chromatography with diode array detection and electrospray quadrupole time-of-flight-type tandem mass spectrometry in the positive ion mode. The fragmentation of protonated molecular ions including low-abundance parent ions, [M+H]+ for five known epipolythiodioxopiperazines, dethiotetra(methylthio)chetomin, chaetocochins A-C, and chetomin, was carried out using low-energy collision-induced electrospray ionization tandem spectrometry. It was found that McLafferty rearrangements occurred in the CID processes and produced a complementary pair of characteristic fragment ions containing piperazine rings (fused and unfused), especially to determine the number of S atoms on each ring. The fragmentation differential between [M+H]+ and [M+Na]+ was uncovered. Complementary fragmentation information obtained from [M+H]+ and [M+Na]+ precursor ions is especially valuable for rapid identification of epipolythiodioxopiperazines. A likely known compound, possibly related to chetoseminudin A, and three new species of epipolythiodioxopiperazines from the fungus C. cochliodes were identified or tentatively characterized based on tandem mass spectra of known ones.

Electrospray tandem mass spectrometry of epipolythiodioxopiperazines.

Low-energy collision-induced electrospray ionization tandem mass spectrometry ESI-CID-MS/MS (in the positive ion mode) was used for the structural characterization of a series of five representative epioplythiodioxopipreazines: dethiotetra(methylthio)chemotin, chaetocochins A, B and C, and chemotin isolated from the fungus Chaetomium cochliodes. The fragmentation pathways were elucidated by ESI-IT-MS(n). The elemental compositions of most of the product ions were confirmed by low-energy ESI-CID-QTOF-MS/MS analyses. The loss of the S(2) molecule seems always to be the first when the S--S bond is present. The loss of 77 Da corresponding to the loss of the [CH(3)SCH(2)O]' radical was diagnostic for chaetocochins A and B, in which the two piperazines rings are linked by an acetal group. It was found that a McLafferty rearrangement plays a significant role in the skeleton fragmentation of theses series of studied complex multicyclic piperazine compounds. This MacLafferty rearrangement affords the product ions at m/z 416 and 400, containing the two piperazine rings belonging to the epipolythiodioxopipreazines. In addition, the pentacyclic rearrangement involving the loss of the SMe(.) radical seems to occur in the presence of the unfused ring. Finally the product ions at m/z 635 and 591 seem to be the characteristic ions for chaetocochin A.