Factors affecting lateral mass screw placement at C-7.

Object: The C-7 lateral mass has been considered difficult to fit with instrumentation because of its unique anatomy. Of the methods that exist for placing lateral mass screws, none particularly accommodates this anatomical variation. The authors have related 12 distinct morphological measures of the C-7 lateral mass to the ability to place a lateral mass screw using the Magerl, Roy-Camille, and a modified Roy-Camille method.

Deformation of the lowermost mantle from seismic anisotropy.

The lowermost part of the Earth's mantle-known as D″-shows significant seismic anisotropy, the variation of seismic wave speed with direction. This is probably due to deformation-induced alignment of MgSiO(3)-post-perovskite (ppv), which is believed to be the main mineral phase present in the region. If this is the case, then previous measurements of D″ anisotropy, which are generally made in one direction only, are insufficient to distinguish candidate mechanisms of slip in ppv because the mineral is orthorhombic.

Understanding equivalence and noninferiority testing.

Increasingly, the goal of many studies is to determine if new therapies have equivalent or noninferior efficacies to the ones currently in use. These studies are called equivalence/noninferiority studies, and the statistical methods for their analysis require only simple modifications to the traditional hypotheses testing framework. Nevertheless, important and subtle issues arise with the application of such methods.

MICA polymorphism identified by whole genome array associated with NKG2D-mediated cytotoxicity in T-cell large granular lymphocyte leukemia.

Background: Large granular lymphocyte leukemia is a semi-autonomous clonal proliferation of cytotoxic T cells accompanied by immune cytopenias and various autoimmune conditions. Due to the rarity of this disease and its association with autoimmune diseases, a theoretical germline or somatic mutation might have significant penetrance, thus enabling detection, even from samples of suboptimal size, through genome-wide association studies.

Design And Methods: To investigate a non-mendelian genetic predisposition to large granular lymphocyte leukemia, we used a step-wise method for gene discovery.

Absence of an association between glucose levels and surgical site infections in patients undergoing craniotomies for brain tumors.

Object: In select patient populations, hyperglycemia has been shown to increase the risk of surgical site infection (SSI), whereas stringent glucose control has improved outcomes. To date, no study has focused on whether SSIs in patients with brain tumors undergoing resection are associated with hyperglycemia.

Methods: The authors performed a retrospective chart review of patients who underwent a craniotomy after receiving a diagnosis of brain tumor.

Factors associated with intraoperative floppy iris syndrome.

Purpose: To identify factors associated with intraoperative floppy iris syndrome (IFIS) in patients undergoing routine phacoemulsification.

Design: Comparative case series.

Participants: Analysis of 899 eyes of 660 patients undergoing routine cataract surgery.

Methyl 3-amino-2,3,6,-trideoxy-L-hexopyranosides in DFT level theory conformational studies.

Geometry optimizations at the B3LYP level of density functional theory are reported for the (1)C4 and (4)C1 conformations of four theoretically possible alpha and beta methyl 3-amino-2,3,6-trideoxy-L-hexopyranosides. The Gibbs free energies, relative Gibbs free energies, and geometry parameters are presented for all the optimized structures. Conformational analysis of the pyranose ring is performed for each stereoisomer on the basis of calculated rotamer populations.

Methyl 4-O-acetyl-3-azido- and 3-azido-4-O-methylsulfonyl-2,3,6,-trideoxyhex-5- enopyranosides in DFT-level conformational studies.

Geometry optimizations at the B3LYP level of density functional theory (DFT) are reported for methyl 4-O-acetyl-3-azido- and 3-azido-4-O-methylsulfonyl-2,3,6-trideoxy-alpha,beta-d-threo- and -beta-d-erythro-hex-5-enopyranosides. The most stable conformers for each compound are presented, along with the corresponding enthalpies and Gibbs free energies. The influence of the exocyclic double bond on the chair conformation is discussed.

Proton-acceptor properties and capability for mutarotation of some glucosylamines in methanol.

N-(m-Nitrophenyl)-beta-D-glucopyranosylamine (Gln), N-(N-methylphenyl)-beta-D-glucopyranosylamine (Glm), N-beta-D-glucopyranosylpyrazole (Glp), and N-beta-D-glucopyranosylimidazole (Gli) have been synthesized. Their basicity constants, pKb, determined in methanol were, respectively, 14.99, 14.

Acid-catalyzed isomerization of methyl 2-deoxy-D-arabino-hexosides: equilibria, kinetics and mechanism.

Four isomers of methyl 2-deoxy-D-arabino-hexosides were isolated by HPLC as chromatographically homogeneous compounds. The rates of pyranoside isomerization (alpha(p) and beta(p)) at 40 degrees C and of furanoside isomerization (alpha(f) and beta(f)) at 26 degrees C were determined. A mechanism has been suggested for transformations taking place during isomerization of methyl 2-deoxy-D-arabino-hexosides in methanolic solution catalyzed with hydrogen chloride.

Crystal structure of N-(tri-O-acetyl-alpha-D-xylopyranosyl)pyridinium bromide.

The structure of N-(2,3,4-tri-O-acetyl-alpha-D-xylopyranosyl)pyridinium bromide was determined by X-ray crystallography and 1H NMR spectroscopy. Two xylopyranosyl moieties crystallize with three water molecules and there is a novel pattern of Br(-) and H(2)O contacts. Both xylopyranosyl rings in the asymmetric unit have the 1C(4) conformation, with all three axial O-Ac groups.

Molecular and crystal structures of N-(beta-D-galactopyranosyl)pyridinium bromide and its per-O-acetylated derivative.

1H NMR spectroscopy and X-ray diffraction data are described for N-(2,3,4,6-tetra-O-acetyl-beta-D-galactopyranosyl)pyridinium bromide and N-(beta-D-galactopyranosyl)pyridinium bromide. X-ray crystallography revealed that the O-acetylated salt crystallizes with two molecules of water and one molecule of ethanol.

Preparation, chemical and crystal structures of N-(2-acetamido-3,4,6-tri-O-acetyl-2-deoxy-beta-D-glucopyranosyl)pyridinium chloride.

Preparation and isolation of N-(2-acetamido-3,4,6-tri-O-acetyl-2-deoxy-beta-D-glucopyranosyl)pyridinium chloride are described. Its structure was determined by 1H NMR spectroscopy and X-ray analysis. X-ray crystallography revealed that the salt crystallizes with one molecule of water.