Hematology and serum biochemistry of free-ranging mantled howler monkeys (Alouatta palliata) at La Pacifica, Costa Rica.

BACKGROUND: Hematologic and blood biochemical values are key tools for assessing primate health. A long-term behavioral study of howler monkeys at a single site (La Pacífica, Guanacaste, Costa Rica), afforded the opportunity to develop baseline values for a large group of animals, evaluating differences between adult males and females and comparing to a report in the same population two decades later. METHODS: In 1998, 64 free-ranging mantled howler monkeys were anesthetized and sampled for hematologic and biochemical analysis. RESULTS: Blood analysis is reported for 29 adult females, 9 juvenile females, 19 adult males and 3 juvenile males. Four adults were excluded due to external injury or disease. There were few significant differences between adult females, juvenile females, and adult males. CONCLUSIONS: Baseline blood parameters are useful for determining normal values for howler monkey populations. The values for total protein, blood urea nitrogen, glucose, liver enzymes and potassium differed from a later study in 2019 may indicate changes that are influencing howler monkey health.

The effect of alkylation on the micro-solvation of ethers revealed by highly localized water librational motion.

The specific far-infrared spectral signatures associated with highly localized large-amplitude out-of-plane librational motion of water molecules have recently been demonstrated to provide sensitive spectroscopic probes for the micro-solvation of organic molecules [Mihrin et al., Phys. Chem. Chem. Phys. 21(4), 1717 (2019)]. The present work employs this direct far-infrared spectroscopic approach to investigate the non-covalent intermolecular forces involved in the micro-solvation of a selection of seven ether molecules with systematically varied alkyl substituents: dimethyl ether, diethyl ether, diisopropyl ether, ethyl methyl ether, t-butyl methyl ether, and t-butyl ethyl ether. The ranking of the observed out-of-plane water librational band signatures for this selected series of ether-water complexes embedded in inert neon matrices at 4 K reveals information about the interplay of directional intermolecular hydrogen bond motifs and non-directional and long-range dispersion interactions for the micro-solvated structures. These far-infrared observables differentiate minor subtle effects introduced by specific alkyl substituents and serve as rigorous experimental benchmarks for modern quantum chemical methodologies of various levels of scalability, which often fail to accurately predict the structural variations and corresponding vibrational signatures of the closely related systems. The accurate interaction energies of the series of ether-water complexes have been predicted by the domain based local pair natural orbital coupled cluster theory with single-, double-, and perturbative triple excitations, followed by a local energy decomposition analysis of the energy components. In some cases, the secondary dispersion forces are in direct competition with the primary intermolecular hydrogen bonds as witnessed by the specific out-of-plane librational signatures.

Far-Infrared Investigation of the Benzene-Water Complex: The Identification of Large-Amplitude Motion and Tunneling Pathways.

The far-infrared spectrum of the weakly OH···π hydrogen-bonded benzene-water complex has been studied in neon and argon matrices, below 30 K. The in-plane water libration has been observed in both neon and argon for H2O and D2O complexed with C6H6 and C6D6 but not for the corresponding complexes involving HDO. Both H2O and D2O can tunnel between the two possible hydrogen bonds. This is not possible for HDO. The reported far-infrared observations have implications for the interpretation of the previously obtained molecular beam microwave spectrum of the benzene-water complex.

Rare genetic variants suggest dysregulation of signaling pathways in low- and high-risk patients developing severe ovarian hyperstimulation syndrome.

PURPOSE: To investigate if rare gene variants in women with severe ovarian hyperstimulation syndrome (OHSS) provide clues to the mechanisms involved in the syndrome. METHODS: Among participants in a prospective randomized study (Toftager et al. 2016), six women with predicted low and six women with predicted high risk of OHSS developing severe OHSS (grades 4 and 5, Golan classification) were selected. In the same cohort, six plus six matched controls developing no signs of OHSS (Golan grade 0) were selected. Whole-exome sequencing was performed. Analysis using a predefined in silico OHSS gene panel, variant filtering, and pathway analyses was done. RESULTS: We found no convincing monogenetic association with the development of OHSS using the in silico gene panel. Pathway analysis of OHSS variant lists showed substantial overlap in highly enriched top pathways (p value range p < 0.0001 and p > 9.8E-17) between the low- and high-risk group developing severe OHSS, i.e., "the integrin-linked kinase (ILK) signaling pathway" and the "axonal guidance signaling pathway," both being connected to vasoactive endothelial growth factor (VEGF) and endothelial function. CONCLUSION: Rare variants in OHSS cases with two distinct risk profiles enrich the same signaling pathways linked to VEGF and endothelial function. Clarification of the mechanism as well as potentially defining genetic predisposition of the high vascular permeability is important for future targeted treatment and prevention of OHSS; the potential roles of ILK signaling and the axonal guidance signaling need to be validated by functional studies.

High-Resolution Infrared Synchrotron Investigation of (HCN)2 and a Semi-Experimental Determination of the Dissociation Energy D0.

The high-resolution infrared absorption spectrum of the donor bending fundamental band ν 61 of the homodimer (HCN)2 has been collected by long-path static gas-phase Fourier transform spectroscopy at 207 K employing the highly brilliant 2.75 GeV electron storage ring source at Synchrotron SOLEIL. The rovibrational structure of the ν 61 transition has the typical appearance of a perpendicular type band associated with a Σ-Π transition for a linear polyatomic molecule. The total number of 100 assigned transitions are fitted employing a standard semi-rigid linear molecule Hamiltonian, providing the band origin ν0 of 779.05182(50) cm-1 together with spectroscopic parameters for the degenerate excited state. This band origin, blue-shifted by 67.15 cm-1 relative to the HCN monomer, provides the final significant contribution to the change of intra-molecular vibrational zero-point energy upon HCN dimerization. The combination with the vibrational zero-point energy contribution determined recently for the class of large-amplitude inter-molecular fundamental transitions then enables a complete determination of the total change of vibrational zero-point energy of 3.35±0.30 kJ mol-1 . The new spectroscopic findings together with previously reported benchmark CCSDT(Q)/CBS electronic energies [Hoobler et al. ChemPhysChem. 19, 3257-3265 (2018)] provide the best semi-experimental estimate of 16.48±0.30 kJ mol-1 for the dissociation energy D0 of this prototypical homodimer.

Highly localized H2O librational motion as a far-infrared spectroscopic probe for microsolvation of organic molecules.

The most prominent spectroscopic observable for the hydrogen bonding between individual molecules in liquid water is the broad absorption band detected in the spectral region between 300 and 900 cm-1. The present work demonstrates how the associated large-amplitude out-of-plane OH librational motion of H2O molecules also directly reflects the microsolvation of organic compounds. This highly localized OH librational motion of the first solvating H2O molecule causes a significant change of dipole moment and gives rise to a strong characteristic band in the far-infrared spectral region, which is correlated quantitatively with the complexation energy. The out-of-plane OH librational band origins ranging from 324.5 to 658.9 cm-1 have been assigned experimentally for a series of four binary hydrogen-bonded H2O complexes embedded in solid neon involving S-, O- and N-containing compounds with increasing hydrogen bond acceptor capability. The hydrogen bond energies for altogether eight binary H2O complexes relative to the experimental value of 13.2 ± 0.12 kJ mol-1 for the prototypical (H2O)2 system [Rocher-Casterline et al., J. Chem. Phys., 2011, 134, 211101] are revealed directly by these far-infrared spectroscopic observables. The far-infrared spectral signatures are able to capture even minor differences in the hydrogen bond acceptor capability of O atoms with slightly different alkyl substituents in the order H-O-C(CH3)3 > CH3-O-CH3 > H-O-CH(CH3)2 > H-O-CH2CH3.

Transparency and sustainability in global commodity supply chains.

Over the last few decades rapid advances in processes to collect, monitor, disclose, and disseminate information have contributed towards the development of entirely new modes of sustainability governance for global commodity supply chains. However, there has been very little critical appraisal of the contribution made by different transparency initiatives to sustainability and the ways in which they can (and cannot) influence new governance arrangements. Here we seek to strengthen the theoretical underpinning of research and action on supply chain transparency by addressing four questions: (1) What is meant by supply chain transparency? (2) What is the relevance of supply chain transparency to supply chain sustainability governance? (3) What is the current status of supply chain transparency, and what are the strengths and weaknesses of existing initiatives? and (4) What propositions can be advanced for how transparency can have a positive transformative effect on the governance interventions that seek to strengthen sustainability outcomes? We use examples from agricultural supply chains and the zero-deforestation agenda as a focus of our analysis but draw insights that are relevant to the transparency and sustainability of supply chains in general. We propose a typology to distinguish among types of supply chain information that are needed to support improvements in sustainability governance, and illustrate a number of major shortfalls and systematic biases in existing information systems. We also propose a set of ten propositions that, taken together, serve to expose some of the potential pitfalls and undesirable outcomes that may result from (inevitably) limited or poorly designed transparency systems, whilst offering guidance on some of the ways in which greater transparency can make a more effective, lasting and positive contribution to sustainability.

Changes in circulating inflammatory markers following febrile non-haemolytic transfusion reactions to leucoreduced red cells.

It would be desirable to be able to distinguish fever as a result of febrile non-haemolytic transfusion reactions (FNHTR) from other febrile conditions. To further characterize the inflammatory feature of FNHTR, we measured a large panel of inflammatory markers in pre- and posttransfusion plasma samples from patients with and without FNHTR following the transfusion of leucoreduced red blood cells. As FNHTR patients only displayed a significant increase in IL-6, we conclude that changes in plasma cytokine levels during FNHTR are unlikely to be used diagnostically. An incidental finding of a distinct cytokine pattern in pretransfusion samples from FNHTR patients warrants further investigations, as it might be used to characterize the nature of FNHTR and to predict the risk of these adverse events.

THz spectroscopy of weakly bound cluster molecules in solid para-hydrogen: a sensitive probe of van der Waals interactions.

The present work demonstrates that 99.9% enriched solid para-H2 below 3 K provides an excellent inert and transparent medium for the exploration of large-amplitude intermolecular vibrational motion of weakly bound van der Waals cluster molecules in the THz spectral region. THz absorption spectra have been generated for CO2/H2O and CS2/H2O mixtures embedded in enriched solid para-H2 and numerous observed transitions associated with large-amplitude librational motion of the weakly bound binary CO2H2O and CS2H2O van der Waals cluster molecules have been assigned together with tentative assignments for the ternary CS2(H2O)2 system. The interaction strength, directionality and anharmonicity of the weak van der Waals "bonds" between the molecules can be characterized via these THz spectral signatures and yield rigorous benchmarks for high-level ab initio methodologies. It is suggested that even a less stable linear conformation of the ternary CS2(H2O)2 system, where one H2O molecule is linked to each S atom of the CS2 subunit, may be formed due to the kinetics associated with the mobility of free H2O molecules in the soft para-H2 medium. In addition, the spectroscopic observations confirm a linear and planar global intermolecular potential energy minimum for the binary CS2H2O system with C2v symmetry, where the O atom on the H2O molecule is linked to one of the S atoms on the CS2 subunit. A semi-experimental value for the vibrational zero-point energy contribution of 1.93 ± 0.10 kJ mol-1 from the class of large-amplitude intermolecular vibrational modes is proposed. The combination with CCSD(T)/CBS electronic energy predictions provides a semi-experimental estimate of 5.08 ± 0.15 kJ mol-1 for the binding energy D0 of the CS2H2O van der Waals system.

High-resolution synchrotron terahertz investigation of the large-amplitude hydrogen bond librational band of (HCN)2.

The high-resolution terahertz absorption spectrum of the large-amplitude intermolecular donor librational band ν of the homodimer (HCN)2 has been recorded by means of long-path static gas-phase Fourier transform spectroscopy at 207 K employing a highly brilliant electron storage ring source. The rovibrational structure of the ν band has the typical appearance of a perpendicular type band of a Σ-Π transition for a linear polyatomic molecule. The generated terahertz spectrum is analyzed employing a standard semi-rigid linear molecule Hamiltonian, yielding a band origin ν0 of 119.11526(60) cm-1 together with values for the excited state rotational constant B', the excited state quartic centrifugal distortion constant DJ' and the l-type doubling constant q for the degenerate state associated with the ν mode. The until now missing donor librational band origin enables the determination of an accurate experimental value for the vibrational zero-point energy of 2.50 ± 0.05 kJ mol-1 arising from the entire class of large-amplitude intermolecular modes. The spectroscopic findings are complemented by CCSD(T)-F12b/aug-cc-pV5Z (electronic energies) and CCSD(T)-F12b/aug-cc-pVQZ (force fields) electronic structure calculations, providing a (semi)-experimental value of 17.20 ± 0.20 kJ mol-1 for the dissociation energy D0 of this strictly linear weak intermolecular CHN hydrogen bond.

Regular brief interruptions to sitting after a high-energy evening meal attenuate glycemic excursions in overweight/obese adults.

BACKGROUND AND AIMS: Modern Western lifestyles are characterized by consumption of approximately 45% of total daily energy intake at the evening meal, followed by prolonged sitting while watching television (TV), which may deleteriously impact glycemic control. After a high-energy evening meal (dinner), we examined whether regular, brief activity bouts during TV commercial breaks could acutely lower postprandial glucose and insulin responses in overweight/obese adults, compared to prolonged uninterrupted sitting. METHODS AND RESULTS: Nine overweight/obese adults (29.7 ± 4.06 kg m-2; aged 32 ± 3 years; 5 male) completed two laboratory-based conditions of three and a half hours: prolonged sitting during TV viewing (SIT); and, prolonged sitting interrupted every 20 min with 3 min of light-intensity body-weight resistance activities (active commercial breaks; ACBs). Venous postprandial glucose and insulin responses to dinner were calculated as positive incremental area under the curve (iAUC) from baseline. Interstitial glucose was measured using a continuous glucose monitor and quantified as total AUC (tAUC). Compared to SIT, plasma glucose iAUC was reduced by 33% [3.4 ± 1.0 vs 5.1 ± 1.0 (mean ± SEM) mmol h·L-1, p = 0.019] and plasma insulin iAUC by 41% (813 ± 224 vs 1373 ± 224, p = 0.033 pmol h·L-1) for the ACB condition. During the ACB condition there was a significant reduction in interstitial glucose tAUC (24.4 ± 5.2 vs 26.9 ± 5.2 mmol h·L-1, p < 0.001), but this did not persist beyond the laboratory observation period. CONCLUSIONS: Regular brief light-intensity activity bouts can attenuate glycemic responses during television viewing time following a high-energy evening meal in overweight/obese adults.

Blood flow after contraction and cuff occlusion is reduced in subjects with muscle soreness after eccentric exercise.

Delayed onset muscle soreness (DOMS) occurs within 1-2 days after eccentric exercise, but the mechanism mediating hypersensitivity is unclear. This study hypothesized that eccentric exercise reduces the blood flow response following muscle contractions and cuff occlusion, which may result in accumulated algesic substances being a part of the sensitization in DOMS. Twelve healthy subjects (five women) performed dorsiflexion exercise (five sets of 10 repeated eccentric contractions) in one leg, while the contralateral leg was the control. The maximal voluntary contraction (MVC) of the tibialis anterior muscle was recorded. Blood flow was assessed by ultrasound Doppler on the anterior tibialis artery (ATA) and within the anterior tibialis muscle tissue before and immediately after 1-second MVC, 5-seconds MVC, and 5-minutes thigh cuff occlusion. Pressure pain thresholds (PPTs) were recorded on the tibialis anterior muscle. All measures were done bilaterally at day 0 (pre-exercise), day 2, and day 6 (post-exercise). Subjects scored the muscle soreness on a Likert scale for 6 days. Eccentric exercise increased Likert scores at day 1 and day 2 compared with day 0 (P<.001). Compared with pre-exercise (day 0), reduced PPT (~25%, P<.002), MVC (~22%, P<.002), ATA diameter (~8%, P<.002), ATA post-contraction/occlusion blood flow (~16%, P<.04), and intramuscular peak blood flow (~23%, P<.03) were found in the DOMS leg on day 2 but not in the control leg. These results showed that eccentric contractions decreased vessel diameter, impaired the blood flow response, and promoted hyperalgesia. Thus, the results suggest that the blood flow reduction may be involved in the increased pain response after eccentric exercise.

Competition between weak OH⋯π and CH⋯O hydrogen bonds: THz spectroscopy of the C2H2-H2O and C2H4-H2O complexes.

THz absorption spectra have been recorded for the weakly bound molecular complexes of H2O with C2H4 and C2H2 embedded in cryogenic neon matrices at 2.8 K. The observation and assignment of a large-amplitude acceptor OH librational mode of the C2H2-H2O complex at 145.5 cm-1 confirms an intermolecular CH⋯O hydrogen-bonded configuration of C2v symmetry with the H2O subunit acting as the hydrogen bond acceptor. The observation and assignment of two large-amplitude donor OH librational modes of the C2H4-H2O complex at 255.0 and 187.5 cm-1, respectively, confirms an intermolecular OH⋯π hydrogen-bonded configuration with the H2O subunit acting as the hydrogen bond donor to the π-cloud of C2H4. A (semi)-empirical value for the change of vibrational zero-point energy of 4.0-4.1 kJ mol-1 is proposed and the combination with quantum chemical calculations at the CCSD(T)-F12b/aug-cc-pVQZ level provides a reliable estimate of 7.1 ± 0.3 kJ mol-1 for the dissociation energy D0 of the C2H4-H2O complex. In addition, tentative assignments for the two strongly infrared active OH librational modes of the ternary C2H4-HOH-C2H4 complex having H2O as a doubly OH⋯π hydrogen bond donor are proposed at 213.6 and 222.3 cm-1. The present findings demonstrate that the relative stability of the weak hydrogen bond motifs is not entirely rooted in differences of electronic energy but also to a large extent by differences in the vibrational zero-point energy contributions arising from the class of large-amplitude intermolecular modes.

Probing the global potential energy minimum of (CH2O)2: THz absorption spectrum of (CH2O)2 in solid neon and para-hydrogen.

The true global potential energy minimum configuration of the formaldehyde dimer (CH2O)2, including the presence of a single or a double weak intermolecular CH⋯O hydrogen bond motif, has been a long-standing subject among both experimentalists and theoreticians as two different energy minima conformations of Cs and C2h symmetry have almost identical energies. The present work demonstrates how the class of large-amplitude hydrogen bond vibrational motion probed in the THz region provides excellent direct spectroscopic observables for these weak intermolecular CH⋯O hydrogen bond motifs. The combination of concentration dependency measurements, observed isotopic spectral shifts associated with H/D substitutions and dedicated annealing procedures, enables the unambiguous assignment of three large-amplitude infrared active hydrogen bond vibrational modes for the non-planar Cs configuration of (CH2O)2 embedded in cryogenic neon and enriched para-hydrogen matrices. A (semi)-empirical value for the change of vibrational zero-point energy of 5.5 ± 0.3 kJ mol-1 is proposed for the dimerization process. These THz spectroscopic observations are complemented by CCSD(T)-F12/aug-cc-pV5Z (electronic energies) and MP2/aug-cc-pVQZ (force fields) electronic structure calculations yielding a (semi)-empirical value of 13.7 ± 0.3 kJ mol-1 for the dissociation energy D0 of this global potential energy minimum.

The donor OH stretching-libration dynamics of hydrogen-bonded methanol dimers in cryogenic matrices.

FTIR spectra of the methanol dimer trapped in neon matrices are presented. The fundamental, overtone and combination bands involving the donor OH libration and stretching motions were observed in order to extract relevant anharmonicity constants. We find a stretching-libration coupling constant of +43(5) cm(-1) and a diagonal librational anharmonicity constant of -71(5) cm(-1). The spectra are compared to a number of VPT2 calculations and a torsionally localized monomer model in order to enhance previous explanations of the observable OH stretching red-shift upon dimerization.

Discrepancy in compliance between the clinical and genetic diagnosis of choroidal hypoplasia in Danish Rough Collies and Shetland Sheepdogs.

Collie eye anomaly (CEA) is a congenital, inherited ocular disorder which is widespread in herding breeds. Clinically, the two major lesions associated with CEA are choroidal hypoplasia (CH) and coloboma, and both lesions are diagnosed based on ophthalmological examination. A 7.8-kb intronic deletion in the gene encoding non-homologous end-joining factor 1 (NHEJ1) has been reported to be the causative mutation underlying CH when present in the homozygous state. In this study, we have investigated the compliance between the clinical and genetic diagnosis of CH in the Danish Rough Collie and Shetland Sheepdog populations. Our results show that the deletion in NHEJ1 is not predictive for CH in the Danish Rough Collie population, whereas the clinical and genetic diagnosis is in accordance with each other in the Shetland Sheepdog population. Based on these results, it can be concluded that the intronic deletion in NHEJ1 is not the causative mutation but, rather, a marker linked to the locus underlying the trait in some populations but linked to both the wild-type and CH-causing locus in most dogs in the Danish Rough Collie population.

Breaking up Prolonged Sitting does not Alter Postprandial Glycemia in Young, Normal-Weight Men and Women.

A randomized, controlled, cross-over study was used to investigate the effects of breaking up prolonged sitting with low intensity physical activity on postprandial blood glucose concentrations in healthy, young, normal-weight adults. 14 men (n=6) and women (n=8) were assigned to 2.5 h of prolonged sitting (CON) and 2.5 h of prolonged sitting with 2-min bouts of walking every 20 min (LIPA). After ingesting a standardized test drink, capillary blood was sampled every 10 min to establish a postprandial blood glucose profile. Based on individual glucose responses, peak blood glucose, time-to-peak glucose, and incremental area under the glucose curve (iAUC) were determined. Paired sample t-tests were used to detect differences between trials. Peak blood glucose (p=0.55) and iAUC (CON: 252 mmol·L-1·2.5 h-1 [163-340]; LIPA: 214 mmol·L-1·2.5 h-1 [146-282]; p=0.45) were not different between trials. Also, time-to-peak glucose was not different between LIPA and CON (p=0.37). Taking advantage of high temporal resolution blood glucose profiles, we showed that breaking up prolonged sitting with low-intensity physical activity does not alter the postprandial blood glucose response in young, healthy, normal-weight adults. Our results indicate that postprandial glycemic control is maintained during prolonged sitting in young, healthy adults.

Risk factors for Escherichia coli O157 on beef cattle ranches located near a major produce production region.

Our goal was to identify climate variables and management practices associated with the presence of E. coli O157 in rangeland cow-calf operations located in a major leafy green production region in the California Central Coast. E. coli O157 was present in 2·6% (68/2654) of faecal, 1·5% (3/204) of water and 1·1% (1/93) of sediment samples collected on eight ranches over 2.5 years. Five (62·5%) ranches were positive at least once during the study. The odds of detecting E. coli O157 in faecal samples was higher during periods of higher maximum soil temperature, higher maximum relative humidity, and larger herd sizes, but decreased as wind speed increased. Molecular subtyping of isolates from cattle faeces and streams/sediments suggested minimal movement of strains between ranches. The findings suggest that E. coli O157 prevalence is relatively low on cow-calf ranches in this region, spatially constrained, but may vary by weather conditions and herd size.

The influence of large-amplitude librational motion on the hydrogen bond energy for alcohol-water complexes.

The far-infrared absorption spectra have been recorded for hydrogen-bonded complexes of water with methanol and t-butanol embedded in cryogenic neon matrices at 2.8 K. The partial isotopic substitution of individual subunits enabled by a dual inlet deposition procedure provides for the first time unambiguous assignments of the intermolecular high-frequency out-of-plane and low-frequency in-plane donor OH librational modes for mixed alcohol-water complexes. The vibrational assignments confirm directly that water acts as the hydrogen bond donor in the most stable mixed complexes and the tertiary alcohol is a superior hydrogen bond acceptor. The class of large-amplitude donor OH librational motion is shown to account for up to 5.1 kJ mol(-1) of the destabilizing change of vibrational zero-point energy upon intermolecular OHO hydrogen bond formation. The experimental findings are supported by complementary electronic structure calculations at the CCSD(T)-F12/aug-cc-pVTZ level of theory.

Spectroscopic identification of ethanol-water conformers by large-amplitude hydrogen bond librational modes.

The far-infrared absorption spectra have been recorded for hydrogen-bonded complexes of water with ethanol embedded in cryogenic neon matrices at 2.8 K. The partial isotopic H/D-substitution of the ethanol subunit enabled by a dual inlet deposition procedure enables the observation and unambiguous assignment of the intermolecular high-frequency out-of-plane and the low-frequency in-plane donor OH librational modes for two different conformations of the mixed binary ethanol/water complex. The resolved donor OH librational bands confirm directly previous experimental evidence that ethanol acts as the O⋯HO hydrogen bond acceptor in the two most stable conformations. In the most stable conformation, the water subunit forces the ethanol molecule into its less stable gauche configuration upon dimerization owing to a cooperative secondary weak O⋯HC hydrogen bond interaction evidenced by a significantly blue-shift of the low-frequency in-plane donor OH librational band origin. The strong correlation between the low-frequency in-plane donor OH librational motion and the secondary intermolecular O⋯HC hydrogen bond is demonstrated by electronic structure calculations. The experimental findings are further supported by CCSD(T)-F12/aug-cc-pVQZ calculations of the conformational energy differences together with second-order vibrational perturbation theory calculations of the large-amplitude donor OH librational band origins.