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We report a case of infective endocarditis (IE) due to nasal septal perforation during Home oxygen therapy (HOT). A 64‐year‐old man with a history of interstitial pneumonia (IP) and on HOT was hospitalized for dyspnea. Methicillin‐sensitive Staphylococcus aureus (MSSA) was repeatedly detected in blood cultures. Echocardiography revealed tricuspid valve vegetation and regurgitation. The patient was diagnosed with IE, according to the modified Duke criteria. A full‐body examination revealed nasal septal perforation and MSSA was isolated from the nasal cavity. The patient was treated with cefazolin and clindamycin. However, he developed aspiration pneumonia and subsequently died. The portal of entry of MSSA was damaged nasal mucosa, caused by dryness and curettage of the dried nasal mucus during HOT. Nasal septal perforation, a potential complication of HOT, may cause severe bacterial infections. Consequently, diligent nasal care is crucial during HOT. [ABSTRACT FROM AUTHOR]

A two-dimensional (2D) homonuclear exchange NMR spectrum in solids often shows an asymmetric cross-peak pattern, which disturbs a quantitative analysis of peak intensities. When magnetization is prepared using cross polarization (CP), the asymmetry can naively be ascribed to nonequilibrium initial magnetization. We show, however, that the CP effect cannot fully explain the observed mixing-time dependence of the peak intensities in 2D 13C–13C exchange spectra of [2,3-13C] l-alanine (2,3-Ala) under 13C–1H dipolar-assisted rotational resonance (DARR) recoupling, which has recently been proposed for a broadband recoupling method under magic-angle spinning. We develop a theory to describe polarization transfer in a two-spin system under DARR recoupling. By taking into account the effects of the partial spectral overlap among 13C signals, which is a unique feature of DARR recoupling, and 1H–1H flip-flop exchange, we can successfully explain the observed mixing-time dependence of the peak intensities of 2D 13C–13C DARR exchange spectra of 2,3-Ala. A simple initial-rate analysis is also examined. [ABSTRACT FROM AUTHOR]

Formation of the intermolecular beta-sheet is a key event in the aggregation of 42-residue amyloid-beta (Abeta42). We have recently identified a physiological and toxic conformer, the turn positions of which are slightly different from each other, in the aggregates of E22K-Abeta42 (one of the mutants related to cerebral amyloid angiopathy). However, it remains unclear whether the intermolecular beta-sheet in the E22K-Abeta42 aggregates is parallel or antiparallel. We prepared an equal mixture of E22K-Abeta42 aggregates labeled at C(alpha) and those labeled at C=O with (13)C, whose intermolecular (13)C-(13)C distance was estimated by solid-state NMR using rotational resonance (R2). The intermolecular proximity of beta-strands at positions 21 and 30 was less than 6 A, supporting the existence of the intermolecular parallel beta-sheet in the E22K-Abeta42 aggregates as well as in wild-type Abeta42 aggregates. The results also suggest that each conformer would not accumulate alternately, but form a relatively large assembly.

A two-dimensional (2D) homonuclear exchange NMR spectrum in solids often shows an asymmetric cross-peak pattern, which disturbs a quantitative analysis of peak intensities. When magnetization is prepared using cross polarization (CP), the asymmetry can naively be ascribed to nonequilibrium initial magnetization. We show, however, that the CP effect cannot fully explain the observed mixing-time dependence of the peak intensities in 2D (13)C-(13)C exchange spectra of [2,3-(13)C] l-alanine (2,3-Ala) under (13)C-(1)H dipolar-assisted rotational resonance (DARR) recoupling, which has recently been proposed for a broadband recoupling method under magic-angle spinning. We develop a theory to describe polarization transfer in a two-spin system under DARR recoupling. By taking into account the effects of the partial spectral overlap among (13)C signals, which is a unique feature of DARR recoupling, and (1)H-(1)H flip-flop exchange, we can successfully explain the observed mixing-time dependence of the peak intensities of 2D (13)C-(13)C DARR exchange spectra of 2,3-Ala. A simple initial-rate analysis is also examined.