25 research outputs found

    Measurement of long range H,C couplings in natural products in orienting media: a tool for structure elucidation of natural products

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    In this paper we show that water insoluble compounds dissolved in poly-Îł-benzyl-glutamate are amenable to the measurement of a number of homo- and heteronuclear dipolar couplings. The sensitivity and experimental precision of dipolar couplings are sufficient to obtain a good match with the structure. In order to achieve the necessary precision for H,C dipolar couplings between protons and carbons that are not directly bound a new method for the measurement of heteronuclear long range couplings is introduced that allows a one-parameter fit to a HSQC-based experiment as reference experiment. The methodology is applied to menthol (1R, 3S, 4R)

    “Perfecting” pure shift HSQC: full homodecoupling for accurate and precise determination of heteronuclear couplings

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    Fully homodecoupled HSQC spectra can be obtained through the use of a new pulse sequence element, "perfectBIRD". By way of illustration, we show that perfectBIRD decoupling allows one-bond residual dipolar couplings (RDCs), which provide important NMR restraints for structure elucidation, to be measured with outstanding precision, even in methylene groups

    Comparison of external fixation, locking and non-locking palmar plating for unstable distal radius fractures in the elderly

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    This study compares the effectiveness of locking and non-locking palmar plating and external fixation for unstable distal radius fractures in the elderly. In a retrospective match-paired study, 45 patients aged 50 to 70 years who underwent surgery for C1/C2 distal radius fractures were evaluated. The surgical procedures were external fixation or plating with locking or non-locking palmar plates. Radiological and functional outcomes were assessed. Outcomes according to Gartland and Werley, Martini and the Disability of the Arm, Shoulder and Hand (DASH) questionnaire were compared. The locking palmar plate fixation method demonstrated significantly better radiological and functional results in comparison to external fixation and the non-locking palmar plating methods. The subjective assessment of plate fixation proved to be better than that of external fixation. Complications and reoperations were fewer for both plate fixation groups. Our data indicates that most displaced intra-articular distal radius fractures can be treated successfully with the locking palmar plate
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