Crosspolarization with imperfect infrared polarizers

The analysis of vibrational bands is a core application of infrared (IR) spectroscopy. Polarization-dependent measurements enable the study of anisotropic materials. However, imperfect IR polarizers exhibit polarizer leakage, which causes pronounced bandshape and baseline distortions for samples with weak optical anisotropy. Based on the 4 × 4 Mueller-matrix formalism, we propose a polarimetric measurement scheme for handling imperfect polarizers and source prepolarization that delivers correct co- and crosspolarized transmission and reflection IR spectra. The scheme is applied to a weakly anisotropic polypropylene sheet, resolving crosspolarized signatures as small as 5⋅10−5. We determine the polymer's direction-dependent complex refractive index in the vibrational fingerprint range

Infrared ellipsometric study of hydrogen-bonded long-chain thiolates on gold: Towards resolving structural details

A set of newly synthesized aryl-substituted amides of 16-mercaptohexadecanoic acid (R = 4-OH; 3,5-di-OH) are self-assembled on Au(111) substrate. Self assembled monolayers (SAMs) formed by these molecules are studied by ellipsometry from infrared to visible spectral range. Best fit calculations based on the three-phase optical model are employed in order to determine the average tilt angle of the hydrocarbon chains. The data revealed that the SAMs reside in a crystalline-like environment as the long methylene chains predominantly exist in all-trans conformation. The calculated tilt angle of the hydrocarbon chain is decreased by approximately 12° in comparison with the one for the correspondent long-chain n-alkyl thiols. Strong hydrogen bonded networks were detected between the amide proton and the carbonyl oxygen as well as between hydroxyl groups in the end aryl substituents. The transition dipole moments of the C=O, N-H and O-H modes are oriented almost parallel to the gold surface

Infrared ellipsometric study of hydrogen-bonded long-chain thiolates on gold: Towards resolving structural details

A set of newly synthesized aryl-substituted amides of 16-mercaptohexadecanoic acid (R = 4-OH; 3,5-di-OH) are self-assembled on Au(111) substrate. Self assembled monolayers (SAMs) formed by these molecules are studied by ellipsometry from infrared to visible spectral range. Best fit calculations based on the three-phase optical model are employed in order to determine the average tilt angle of the hydrocarbon chains. The data revealed that the SAMs reside in a crystalline-like environment as the long methylene chains predominantly exist in all-trans conformation. The calculated tilt angle of the hydrocarbon chain is decreased by approximately 12° in comparison with the one for the correspondent long-chain n-alkyl thiols. Strong hydrogen bonded networks were detected between the amide proton and the carbonyl oxygen as well as between hydroxyl groups in the end aryl substituents. The transition dipole moments of the C=O, N-H and O-H modes are oriented almost parallel to the gold surface

Probing carbonyl–water hydrogen-bond interactions in thin polyoxazoline brushes

Temperature-responsive oxazoline-based polymer brushes have gained increased attention as biocompatible surfaces. In aqueous environment, they can be tuned between hydrophilic and hydrophobic behavior triggered by a temperature stimulus. This transition is connected with changes in molecule–solvent interactions and results in a switching of the brushes between swollen and collapsed states. This work studies the temperature-dependent interactions between poly(2-oxazoline) brushes and water. In detail, thermoresponsive poly(2-cyclopropyl-2-oxazoline), nonresponsive hydrophilic poly(2-methyl-2-oxazoline), as well as a copolymer of the two were investigated with in situinfrared ellipsometry. Focus was put on interactions of the brushes’ carbonyl groups with water molecules. Different polymer–water interactions could be observed and assigned to hydrogen bonding between C=O groups and water molecules. The switching behavior of the brushes in the range of 20–45°C was identified by frequency shifts and intensity changes of the amide I band

Probing carbonyl-water hydrogen-bond interactions in thin polyoxazoline brushes

Temperature-responsive oxazoline-based polymer brushes have gained increased attention as biocompatible surfaces. In aqueous environment, they can be tuned between hydrophilic and hydrophobic behavior triggered by a temperature stimulus. This transition is connected with changes in molecule–solvent interactions and results in a switching of the brushes between swollen and collapsed states. This work studies the temperature-dependent interactions between poly(2-oxazoline) brushes and water. In detail, thermoresponsive poly(2-cyclopropyl-2-oxazoline), nonresponsive hydrophilic poly(2-methyl-2-oxazoline), as well as a copolymer of the two were investigated with in situ infrared ellipsometry. Focus was put on interactions of the brushes' carbonyl groups with water molecules. Different polymer–water interactions could be observed and assigned to hydrogen bonding between C=O groups and water molecules. The switching behavior of the brushes in the range of 20–45 °C was identified by frequency shifts and intensity changes of the amide I band

Probing carbonyl–water hydrogen-bond interactions in thin polyoxazoline brushes

Temperature-responsive oxazoline-based polymer brushes have gained increased attention as biocompatible surfaces. In aqueous environment, they can be tuned between hydrophilic and hydrophobic behavior triggered by a temperature stimulus. This transition is connected with changes in molecule–solvent interactions and results in a switching of the brushes between swollen and collapsed states. This work studies the temperature-dependent interactions between poly(2-oxazoline) brushes and water. In detail, thermoresponsive poly(2-cyclopropyl-2-oxazoline), nonresponsive hydrophilic poly(2-methyl-2-oxazoline), as well as a copolymer of the two were investigated with in situinfrared ellipsometry. Focus was put on interactions of the brushes’ carbonyl groups with water molecules. Different polymer–water interactions could be observed and assigned to hydrogen bonding between C=O groups and water molecules. The switching behavior of the brushes in the range of 20–45°C was identified by frequency shifts and intensity changes of the amide I band

Diagnosing Overtraining Syndrome: A Scoping Review

Overtraining syndrome (OTS) is a condition characterized by a long-term performance decrement, which occurs after a persisting imbalance between training-related and nontraining-related load and recovery. Because of the lack of a gold standard diagnostic test, OTS remains a diagnosis of exclusion.; To systematically review and map biomarkers and tools reported in the literature as potentially diagnostic for OTS.; PubMed, Web of Science, and SPORTDiscus were searched from database inception to February 4, 2021, and results screened for eligibility. Backward and forward citation tracking on eligible records were used to complement results of database searching.; Studies including athletes with a likely OTS diagnosis, as defined by the European College of Sport Science and the American College of Sports Medicine, and reporting at least 1 biomarker or tool potentially diagnostic for OTS were deemed eligible.; Scoping review following the guidelines of the Joanna Briggs Institute and PRISMA Extension for Scoping Reviews (PRISMA-ScR).; Level 4.; Athletes' population, criteria used to diagnose OTS, potentially diagnostic biomarkers and tools, as well as miscellaneous study characteristics were extracted.; The search yielded 5561 results, of which 39 met the eligibility criteria. Three diagnostic scores, namely the EROS-CLINICAL, EROS-SIMPLIFIED, and EROS-COMPLETE scores (EROS = Endocrine and Metabolic Responses on Overtraining Syndrome study), were identified. Additionally, basal hormone, neurotransmitter and other metabolite levels, hormonal responses to stimuli, psychological questionnaires, exercise tests, heart rate variability, electroencephalography, immunological and redox parameters, muscle structure, and body composition were reported as potentially diagnostic for OTS.; Specific hormones, neurotransmitters, and metabolites, as well as psychological, electrocardiographic, electroencephalographic, and immunological patterns were identified as potentially diagnostic for OTS, reflecting its multisystemic nature. As exemplified by the EROS scores, combinations of these variables may be required to diagnose OTS. These scores must now be validated in larger samples and within female athletes

Investigating the circulating sphingolipidome response to a single high-intensity interval training session within healthy females and males in their twenties (SphingoHIIT): Protocol for a randomised controlled trial [version 2; peer review: 2 approved]

Introduction: Growing scientific evidence indicates that sphingolipids predict cardiometabolic risk, independently of and beyond traditional biomarkers such as low-density lipoprotein cholesterol. To date, it remains largely unknown if and how exercise, a simple, low-cost, and patient-empowering modality to optimise cardiometabolic health, influences sphingolipid levels. The SphingoHIIT study aims to assess the response of circulating sphingolipid species to a single session of high-intensity interval training (HIIT). Methods: This single-centre randomised controlled trial (RCT) will last 11 days per participant and aim to include 32 young and healthy individuals aged 20-29 (50% females). Participants will be randomly allocated to the HIIT (n= 16) or control groups (physical rest, n= 16). Participants will self-sample fasted dried blood spots for three consecutive days before the intervention (HIIT versus rest) to determine baseline sphingolipid levels. Dried blood spots will also be collected at five time points (2, 15, 30, 60min, and 24h) following the intervention (HIIT versus rest). To minimise the dietary influence, participants will receive a standardised diet for four days, starting 24 hours before the first dried blood sampling. For females, interventions will be timed to fall within the early follicular phase to minimise the menstrual cycle's influence on sphingolipid levels. Finally, physical activity will be monitored for the whole study duration using a wrist accelerometer. Ethics and dissemination: The Ethics Committee of Northwest and Central Switzerland approved this protocol (ID 2022–00513). Findings will be disseminated in scientific journals and meetings. Trial Registration The trial was registered on www.clinicaltrials.gov (NCT05390866, https://clinicaltrials.gov/ct2/show/NCT05390866) on May 25, 2022

Erratum: Corrigendum: Sequence and comparative analysis of the chicken genome provide unique perspectives on vertebrate evolution

International Chicken Genome Sequencing Consortium. The Original Article was published on 09 December 2004. Nature432, 695–716 (2004). In Table 5 of this Article, the last four values listed in the ‘Copy number’ column were incorrect. These should be: LTR elements, 30,000; DNA transposons, 20,000; simple repeats, 140,000; and satellites, 4,000. These errors do not affect any of the conclusions in our paper. Additional information. The online version of the original article can be found at 10.1038/nature0315