Structural analysis of plant materials supports the growing interest in their use for chemicals, for example, biofuels. Lignin is a main polymer component formed from three phenolic precursors containing none, one or two OMe groups, i.e. H, G and S units, respectively. Raman spectroscopy offers structural information on lignin. This relies on correct assignment of observations to fundamental vibrations, and today this subject is not without controversy. The present work shows the strength of first principles assignment of lignin model bands. Raman spectra of three H, G, and S phenolic end group models are compared with density functional theory predictions of their vibrational properties. H, G, and S marker bands are found and related to specific vibrations. For the S unit, multiple OMe conformations exist that may all contribute to its Raman spectrum. Two ring deformation modes at approximately 1600 cm(-1) offer a potential route of gaining information on the microenvironment.

BackgroundTo examine if patients with oral lichen planus, oral lichenoid lesions and generalised stomatitis and concomitant contact allergy have more frequent and severe xerostomia, lower unstimulated and chewing-stimulated saliva and citric-acid-stimulated parotid saliva flow rates, and higher salivary concentration of total protein and sIgA than cases without contact allergy and healthy controls.MethodsForty-nine patients (42 women, aged 61.0 ± 10.3 years) and 29 healthy age- and gender-matched subjects underwent a standardised questionnaire on general and oral health, assessment of xerostomia, clinical examination, sialometry, mucosal biopsy and contact allergy testing.ResultsNineteen patients had oral lichen planus, 19 patients had oral lichenoid lesions and 11 patients had generalised stomatitis. 38.8% had contact allergy. Xerostomia was significantly more common and severe in patients (46.9%) than in healthy controls, whereas the saliva flow rates did not differ. The patients had higher sIgA levels in unstimulated and chewing-stimulated saliva than the healthy controls. The total protein concentration in saliva was lower in the unstimulated saliva samples whereas it was higher in the chewing stimulated saliva samples from patients when compared to healthy controls. The differences were not significant and they were irrespective of the presence of contact allergy.ConclusionXerostomia is prevalent in patients with oral lichen planus, lichenoid lesions and generalised stomatitis, but not associated with salivary gland hypofunction, numbers of systemic diseases or medications, contact allergy, age, or gender. Salivary sIgA levels were higher in patients than in healthy controls, but did not differ between patient groups. The total salivary protein concentration was lower in unstimulated saliva samples and higher in chewing-stimulated saliva samples in patients than in healthy controls, but did not differ between patient groups. Our findings do not aid in the discrimination between OLP and OLL and these conditions with or without contact allergic reactions.

Aim Cardiac arrhythmias and sudden deaths have diurnal rhythms in humans. The underlying mechanisms are unknown. Mice with cardiomyocyte‐specific disruption of the molecular clock genes have lower heart rate than control. Because changes in the QT interval on the electrocardiogram is a clinically used marker of risk of arrhythmias, we sought to test if the biological rhythms of QT intervals are dependent on heart rate and if this dependency is changed when the molecular clock is disrupted. Methods We implanted radio transmitters in male mice with cardiomyocyte‐specific Bmal1 knockout (CBK) and in control mice and recorded 24‐h ECGs under diurnal and circadian conditions. We obtained left ventricular monophasic action potentials during pacing in hearts ex vivo. Results Both RR and QT intervals were longer in conscious CBK than control mice (RR: 117 ± 7 vs 110 ± 9 ms, P < .05; and QT: 53 ± 4 vs 48 ± 2 ms, P < .05). The prolonged QT interval was independent of the slow heart rate in CBK mice. The QT interval exhibited diurnal and circadian rhythms in both CBK and control mice. The action potential duration was longer in CBK than in control mice, indicating slower repolarization. Action potential alternans occurred at lower pacing rate in hearts from CBK than control mice (12 ± 3 vs 16 ± 2 Hz, respectively, P < .05). Conclusion The bradycardic CBK mice have prolonged ventricular repolarization independent of the heart rate. Diurnal and circadian rhythms in repolarization are preserved in CBK mice and are not a consequence of the 24‐h rhythm in heart rate. Arrhythmia vulnerability appears to be increased when the cardiac clock is disrupted.

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