Adaptive Response to Solvation in Flexible Molecules: Oligo Hydrates of 4-hydroxy-2-butanone.

Structural changes induced by water play a pivotal role in chemistry and biology but remain challenging to predict, measure, and control at molecular level. Here we explore size-governed gas-phase water aggregation in the flexible molecule 4-hydroxy-2-butanone, modeling the conformational adaptability of flexible substrates to host water scaffolds and the preference for sequential droplet growth. The experiment was conducted using broadband rotational spectroscopy, rationalized with quantum chemical calculations. Two different isomers were observed experimentally from the di- to the pentahydrates (4-hydroxy-2-butanone-(water)n = 2-5), including the 18O isotopologues for the di- and trihydrates. Interestingly, to accommodate water molecules effectively, the heavy atom skeleton of 4-hydroxy-2-butanone reshapes in every observed isomer and does not correspond to the stable conformer of the free monomer. All solvates initiate from the (proton donor) alcohol group but retain the carbonyl group as secondary binding point. The water scaffolds closely resemble those found in the pure water clusters, balancing between the capability of 4-hydroxy-2-butanone for steering the orientation and position of the water molecules and the ability of water to modulate the monomer's conformation. The present work thus provides an accurate molecular answer on how torsionally flexible molecules dynamically adapt to water along progressing solvation.

Estudio transversal. Dolor lumbar y medidas ergonómicas en puestos de trabajo en oficinas / Cross-sectional study. Low back pain and ergonomic measures in office workstations

Introducción: La mayoría de los casos de lumbalgia son de origen muscular y en muchos casos no se identifica una causa subyacente. La prevalencia en trabajadores de oficina es muy variable con valores que pueden llegar hasta el 64%, en muchos casos relacionada con factores ergonómicos y psicosociales. Objetivo: Nuestro objetivo trata de asociar la lumbalgia con dimensiones ergonómicas del puesto de trabajo en oficinistas. Material y Métodos: Se ha diseñado un estudio transversal descriptivo determinando ocho dimensiones ergonómicas, junto con condiciones demográficas y antropométricas de una muestra de trabajadores de oficina. Resultados: Se han analizado los datos de 40 trabajadores, un 77,5% de ellos mujeres, con una edad de 52,1 ± 7,4 años. Ninguna de las medidas determinadas se ha asociado con un riesgo significativo de padecer lumbalgia. Conclusiones: A pesar de la negatividad de nuestros resultados, la relación de lumbalgia con edad, género y hábito sedentario descrita en la literatura, debería facilitar la inclusión de programas de promoción de la salud osteomuscular, orientados a la prevención de la lumbalgia en este colectivo. (AU)

Introduction: Most cases of low back pain are of muscular origin and in many cases no underlying cause is identified. The prevalence in office workers is very variable with values that can reach up to 64%, in many cases related to ergonomic and psychosocial factors. Objetive: Our objective is to associate low back pain with ergonomic dimensions of the workplace in office workers. Material and Methods: A descriptive cross−sectional study was designed to determine eight ergonomic dimensions, together with demographic and anthropometric conditions of a sample of office workers. Results: Data from 40 workers were analyzed, 77.5% of whom were women, with an age of 52.1 ± 7.4 years. None of the measures determined was associated with a significant risk of low back pain. Conclusions: In spite of the negativity of our results, the relationship of low back pain with age, gender and sedentary habits described in the literature should facilitate the inclusion of osteomuscular health promotion programs aimed at preventing low back pain in this group.(AU)

Distribución y características de la certificación de los reumatólogos en México / Distribution and characteristics of the certification of rheumatologists in Mexico

Objetivo: Describir la distribución de los reumatólogos de adultos y pediátricos con certificación vigente en México y los factores asociados a esta distribución. Métodos: Se revisaron las bases de datos del Consejo Mexicano de Reumatología y del Colegio Mexicano de Reumatología de 2020. Se calculó la tasa de reumatólogos por cada 100.000 habitantes por estado de la República Mexicana. Para conocer el número de habitantes por estado, se consultaron los resultados del censo de población del Instituto Nacional de Estadística y Geografía de 2020. Se analizó el número de reumatólogos con certificación vigente por estado, edad y sexo. Resultados: En México hay registrados 1.002 reumatólogos de adultos, con una edad promedio de 48,12±13 años. Predominó el género masculino con una relación de 1,18:1. Se identificaron 94 reumatólogos pediatras, con una edad promedio de 42,25±10,4 años, con predominio del género femenino con una relación de 2,2:1. En la Ciudad de México y Jalisco se reportó más de un reumatólogo/100.000 habitantes en la especialidad de adultos y solo en la Ciudad de México en pediátricos. La certificación vigente es de 65 a 70% en promedio y los factores asociados a una mayor prevalencia fueron edad menor, género femenino y ubicación geográfica. Conclusiones: Existe escasez de reumatólogos en México y en el área pediátrica hay regiones desatendidas. Es importante que las políticas de salud apliquen medidas que permitan una regionalización más equilibrada y eficiente de esta especialidad. Aunque la mayoría de los reumatólogos cuentan con certificación vigente, es necesario establecer estrategias esta proporción.(AU)

Objective: Describe the distribution of adult and pediatric rheumatologists with current certification in Mexico and the factors associated with this distribution. Methods: The databases of the Mexican Council of Rheumatology and the Mexican College of Rheumatology for 2020 were reviewed. The rate of rheumatologists per 100,000 inhabitants by state of the Mexican Republic was calculated. To find out the number of inhabitants by state, the results of the 2020 population census of the National Institute of Statistics and Geography were consulted. The number of rheumatologists with current certification by state, age, and sex was analyzed. Results: In Mexico, there are 1002 registered adult rheumatologists with a mean age of 48.12±13 years. The male gender prevailed with a ratio of 1.18:1. Ninety-four pediatric rheumatologists were identified with a mean age of 42.25±10.4 years, with a predominance of the female gender with a ratio of 2.2:1. In Mexico City and Jalisco, more than one rheumatologist/100,000 inhabitants were reported in the specialty of adults and only in Mexico City in pediatrics. The current certification is 65 to 70% on average and the factors associated with a higher prevalence were younger age, female gender and geographic location. Conclusions: There is a shortage of rheumatologists in Mexico and in the pediatric area there are underserved regions. It is important that health policies apply measures that allow a more balanced and efficient regionalization of this specialty. Although most rheumatologists have current certification, it is necessary to establish strategies to increase this proportion.(AU)

Quantum Tunneling Facilitates Water Motion across the Surface of Phenanthrene.

Quantum tunneling is a fundamental phenomenon that plays a pivotal role in the motion and interaction of atoms and molecules. In particular, its influence in the interaction between water molecules and carbon surfaces can have significant implications for a multitude of fields ranging from atmospheric chemistry to separation technologies. Here, we unveil at the molecular level the complex motion dynamics of a single water molecule on the planar surface of the polycyclic aromatic hydrocarbon phenanthrene, which was used as a small-scale carbon surface-like model. In this system, the water molecule interacts with the substrate through weak O-H···π hydrogen bonds, in which phenanthrene acts as the hydrogen-bond acceptor via the high electron density of its aromatic cloud. The rotational spectrum, which was recorded using chirped-pulse Fourier transform microwave spectroscopy, exhibits characteristic line splittings as dynamical features. The nature of the internal dynamics was elucidated in great detail with the investigation of the isotope-substitution effect on the line splittings in the rotational spectra of the H218O, D2O, and HDO isotopologues of the phenanthrene-H2O complex. The spectral analysis revealed a complex internal dynamic showing a concerted tunneling motion of water involving its internal rotation and its translation between the two equivalent peripheral rings of phenanthrene. This high-resolution spectroscopy study presents the observation of a tunneling motion exhibited by the water monomer when interacting with a planar carbon surface with an unprecedented level of detail. This can serve as a small-scale analogue for water motions on large aromatic surfaces, i.e., large polycyclic aromatic hydrocarbons and graphene.

Distribution and characteristics of the certification of rheumatologists in Mexico.

OBJECTIVE: Describe the distribution of adult and pediatric rheumatologists with current certification in Mexico and the factors associated with this distribution. METHODS: The databases of the Mexican Council of Rheumatology and the Mexican College of Rheumatology for 2020 were reviewed. The rate of rheumatologists per 100,000 inhabitants by state of the Mexican Republic was calculated. To find out the number of inhabitants by state, the results of the 2020 population census of the National Institute of Statistics and Geography were consulted. The number of rheumatologists with current certification by state, age, and sex was analyzed. RESULTS: In Mexico, there are 1002 registered adult rheumatologists with a mean age of 48.12 ±â€¯13 years. The male gender prevailed with a ratio of 1.18:1. Ninety-four pediatric rheumatologists were identified with a mean age of 42.25 ±â€¯10.4 years, with a predominance of the female gender with a ratio of 2.2:1. In Mexico City and Jalisco, more than one rheumatologist/100,000 inhabitants were reported in the specialty of adults and only in Mexico City in pediatrics. The current certification is 65%-70% on average and the factors associated with a higher prevalence were younger age, female gender and geographic location. CONCLUSIONS: There is a shortage of rheumatologists in Mexico and in the pediatric area there are underserved regions. It is important that health policies apply measures that allow a more balanced and efficient regionalization of this specialty. Although most rheumatologists have current certification, it is necessary to establish strategies to increase this proportion.

Reduced IL-8 Secretion by NOD-like and Toll-like Receptors in Blood Cells from COVID-19 Patients.

Severe inflammatory responses are associated with the misbalance of innate and adaptive immunity. TLRs, NLRs, and cytokine receptors play an important role in pathogen sensing and intracellular control, which remains unclear in COVID-19. This study aimed to evaluate IL-8 production in blood cells from COVID-19 patients in a two-week follow-up evaluation. Blood samples were taken at admission (t1) and after 14 days of hospitalization (t2). The functionality of TLR2, TLR4, TLR7/8, TLR9, NOD1, and NOD2 innate receptors and IL-12 and IFN-γ cytokine receptors was evaluated by whole blood stimulation with specific synthetic receptor agonists through the quantification of IL-8, TNF-α, or IFN-γ. At admission, ligand-dependent IL-8 secretion was 6.4, 13, and 2.5 times lower for TLR2, TLR4, and endosomal TLR7/8 receptors, respectively, in patients than in healthy controls. Additionally, IL-12 receptor-induced IFN-γ secretion was lower in COVID-19 patients than in healthy subjects. We evaluated the same parameters after 14 days and observed significantly higher responses for TLR2, TLR4, TLR7/8, TLR9, and NOD1, NOD2, and IFN-γ receptors. In conclusion, the low secretion of IL-8 through stimulation with agonists of TLR2, TLR4, TLR7/8, TLR9, and NOD2 at t1 suggests their possible contribution to immunosuppression following hyperinflammation in COVID-19 disease.

Sulfur-arene interactions: the S⋯π and S-H⋯π interactions in the dimers of benzofuran⋯sulfur dioxide and benzofuran⋯hydrogen sulfide.

Non-covalent interactions between sulfur centers and aromatic rings play important roles in biological chemistry. We examined here the sulfur-arene interactions between the fused aromatic heterocycle benzofuran and two prototype sulfur divalent triatomics (sulfur dioxide and hydrogen sulfide). The weakly-bound adducts were generated in a supersonic jet expansion and characterized with broadband (chirped-pulsed) time-domain microwave spectroscopy. The rotational spectrum confirmed the detection of a single isomer for both heterodimers, consistent with the computational predictions for the global minima. The benzofuran⋯sulfur dioxide dimer exhibits a stacked structure with sulfur closer to benzofuran, while in benzofuran⋯hydrogen sulfide the two S-H bonds are oriented towards the bicycle. These binding topologies are similar to the corresponding benzene adducts, but offer increased interaction energies. The stabilizing interactions are described as S⋯π or S-H⋯π, respectively, using a combination of density-functional theory calculations (dispersion corrected B3LYP and B2PLYP), natural bond orbital theory, energy decomposition and electronic density analysis methods. The two heterodimers present a larger dispersion component, but nearly balanced by electrostatic contributions.

Evolution of Solute-Water Interactions in the Benzaldehyde-(H2O)1-6 Clusters by Rotational Spectroscopy.

The investigation on the preferred arrangement and intermolecular interactions of gas phase solute-water clusters gives insights into the intermolecular potentials that govern the structure and dynamics of the aqueous solutions. Here, we report the investigation of hydrated coordination networks of benzaldehyde-(water)n (n = 1-6) clusters in a pulsed supersonic expansion using broadband rotational spectroscopy. Benzaldehyde (PhCHO) is the simplest aromatic aldehyde that involves both hydrophilic (CHO) and hydrophobic (phenyl ring) functional groups, which can mimic molecules of biological significance. For the n = 1-3 clusters, the water molecules are connected around the hydrophilic CHO moiety of benzaldehyde through a strong CO···HO hydrogen bond and weak CH···OH hydrogen bond(s). For the larger clusters, the spectra are consistent with the structures in which the water clusters are coordinated on the surface of PhCHO with both the hydrophilic CHO and hydrophobic phenyl ring groups being involved in the bonding interactions. The presence of benzaldehyde does not strongly interfere with the cyclic water tetramer and pentamer, which retain the same structure as in the pure water cluster. The book isomer instead of cage or prism isomers of the water hexamer is incorporated into the microsolvated cluster. The PhCHO molecule deviates from the planar structure upon sequential addition of water molecules. The PhCHO-(H2O)1-6 clusters may serve as a simple model system in understanding the solute-water interactions of biologically relevant molecules in an aqueous environment.

Rotational dive into the water clusters on a simple sugar substrate.

Most biomolecular activity takes place in aqueous environments, and it is strongly influenced by the surrounding water molecules. The hydrogen bond networks that these water molecules form are likewise influenced by their interactions with the solutes, and thus, it is crucial to understand this reciprocal process. Glycoaldehyde (Gly), often considered the smallest sugar, represents a good template to explore the steps of solvation and determine how the organic molecule shapes the structure and hydrogen bond network of the solvating water cluster. Here, we report a broadband rotational spectroscopy study on the stepwise hydration of Gly with up to six water molecules. We reveal the preferred hydrogen bond networks formed when water molecules start to form three-dimensional (3D) topologies around an organic molecule. We observe that water self-aggregation prevails even in these early stages of microsolvation. These hydrogen bond networks manifest themselves through the insertion of the small sugar monomer in the pure water cluster in a way in which the oxygen atom framework and hydrogen bond network resemble those of the smallest three-dimensional pure water clusters. Of particular interest is the identification, in both the pentahydrate and hexahydrate, of the previously observed prismatic pure water heptamer motif. Our results show that some specific hydrogen bond networks are preferred and survive the solvation of a small organic molecule, mimicking those of pure water clusters. A many-body decomposition analysis of the interaction energy is also performed to rationalize the strength of a particular hydrogen bond, and it successfully confirms the experimental findings.

Microbiota composition in the lower respiratory tract is associated with severity in patients with acute respiratory distress by influenza.

Several factors are associated with the severity of the respiratory disease caused by the influenza virus. Although viral factors are one of the most studied, in recent years the role of the microbiota and co-infections in severe and fatal outcomes has been recognized. However, most of the work has focused on the microbiota of the upper respiratory tract (URT), hindering potential insights from the lower respiratory tract (LRT) that may help to understand the role of the microbiota in Influenza disease. In this work, we characterized the microbiota of the LRT of patients with Influenza A using 16S rRNA sequencing. We tested if patients with different outcomes (deceased/recovered) and use of antibiotics differ in their microbial community composition. We found important differences in the diversity and composition of the microbiota between deceased and recovered patients. In particular, we detected a high abundance of opportunistic pathogens such as Granulicatella, in patients either deceased or with antibiotic treatment. Also, we found antibiotic treatment correlated with lower diversity of microbial communities and with lower probability of survival in Influenza A patients. Altogether, the loss of microbial diversity could generate a disequilibrium in the community, potentially compromising the immune response increasing viral infectivity, promoting the growth of potentially pathogenic bacteria that, together with altered biochemical parameters, can be leading to severe forms of the disease. Overall, the present study gives one of the first characterizations of the diversity and composition of microbial communities in the LRT of Influenza patients and its relationship with clinical variables and disease severity.

Inducing transient enantiomeric excess in a molecular quantum racemic mixture with microwave fields.

Chiral molecules with low enantiomer interconversion barriers racemize even at cryogenic temperatures due to quantum tunneling, forming a racemic mixture that is impossible to separate using conventional chemical methods. Here we both experimentally and theoretically demonstrate a method to create and probe a state-specific enantiomeric enrichment for such molecular systems. The coherent, non-linear, and resonant approach is based on a microwave six-wave mixing scheme and consists of five phase-controlled microwave pulses. The first three pulses induce a chiral wavepacket in a chosen rotational state, while the consecutive two pulses induce a polarization for a particular rotational transition (listen transition) with a magnitude proportional to the enantiomeric excess created. The experiments are performed with the transiently chiral molecule benzyl alcohol, where a chiral molecular response was successfully obtained. This signal demonstrates that enantiomeric excess can be induced in a quantum racemic mixture of a transiently chiral molecule using the developed microwave six-wave mixing scheme, which is an important step towards controlling non-rigid chiral molecular systems.

π-Stacking Isomerism in Polycyclic Aromatic Hydrocarbons: The 2-Naphthalenethiol Dimer.

π-Stacking is a common descriptor for face-to-face attractive forces between aromatic hydrocarbons. However, the physical origin of this interaction remains debatable. Here we examined π-stacking in a model homodimer formed by two thiol-substituted naphthalene rings. Two isomers of the 2-naphthalenethiol dimer were discovered using rotational spectroscopy, sharing a parallel-displaced crossed orientation and absence of thiol-thiol hydrogen bonds. One of the isomers presents C2 symmetry, structurally analogous to the global minimum of the naphthalene dimer. The experimental data were rationalized with molecular orbital calculations, revealing a shallow potential energy surface. Noncovalent interactions are dominated by dispersion forces according to SAPT energy decomposition. In addition, the reduced electronic density shows a diffuse and extended region of inter-ring interactions, compatible with the description of π-stacking as a competition between dispersion and Pauli repulsion forces.

Competition between In-Plane vs Above-Plane Configurations of Water with Aromatic Molecules: Non-Covalent Interactions in 1,4-Naphthoquinone-(H2O)1-3 Complexes.

Non-covalent interactions between aromatic molecules and water are fundamental in many chemical and biological processes, and their accurate description is essential to understand molecular relative configurations. Here we present the rotational spectroscopy study of the water complexes of the polycyclic aromatic hydrocarbon 1,4-naphthoquinone (1,4-NQ). In 1,4-NQ-(H2O)1,2, water molecules bind through O-H···O and C-H···O hydrogen bonds and are located on the plane of 1,4-NQ. For 1,4-NQ-(H2O)3, in-plane and above-plane water configurations are observed exhibiting O-H···O, C-H···O, and lone pair···π-hole interactions. The observation of different water arrangements for 1,4-NQ-(H2O)3 allows benchmarking theoretical methods and shows that they have great difficulty in predicting energy orderings due to the strong competition of C-H···O binding with π and π-hole interactions. This study provides important insight into water interactions with aromatic systems and the challenges in their modeling.

A(H3N2) antigenic variation of influenza is associated with low vaccine efficacy in the early 2018 influenza season in Mexico City.

OBJECTIVES: We evaluated the VE and the mutations of the viruses present in the Mexican population at the beginning of 2018. METHODS: We diagnosed influenza in outpatients with a high-performance Rapid Influenza Diagnostic Test (RIDT) qRT-PCR. Descriptive statistics were used to describe the study population, while the chi-square test was used to determine clinical variables. VE was analyzed through a negative test design. We sequenced the hemagglutinin (HA) gene, performed a phylogenetic analysis, and analyzed the nonsynonymous substitutions both in and outside antigenic sites. RESULTS: Of the 240 patients analyzed, 42.5% received the trivalent vaccine, and 37.5% were positive for influenza. The VE for the general population for any influenza virus type or subtype was 37.0%, while the VE for the predominant influenza A(H3N2) subtype was the lowest (19.7%). The phylogenetic analysis of HA showed the co-circulation of clades and subclades 3C.2a1, 3C.2a1b, 3C.2a2, 3C.2a2re, 3C.2a3, and 3C.3a with identities approximately 97-98% similar to the vaccine composition. CONCLUSION: Low VE was related to the co-circulation of multiple clades and subclades of influenza A(H3N2), with sufficient genetic and phenotypic distance to allow for the infection of vaccinated individuals.

Correction: Villalobos-González et al. Photoprotection Is Achieved by Photorespiration and Modification of the Leaf Incident Light, and Their Extent Is Modulated by the Stomatal Sensitivity to Water Deficit in Grapevines. Plants 2022, 11, 1050.

In the original publication [...].

Sniffing out camphor: the fine balance between hydrogen bonding and London dispersion in the chirality recognition with α-fenchol.

Binary complexes between the chiral monoterpenoids camphor and α-fenchol were explored with vibrational and rotational jet spectroscopy as well as density functional theory in order to explore how chirality can influence the binding preferences in gas-phase complexes. The global minimum structures of the two diastereomers were assigned. It is found that chirality recognition leads to different compromises in the fine balance between intermolecular interactions. While one isomer features a stronger hydrogen bond, the other one is more tightly arranged and stabilized by larger London dispersion interactions. These new spectroscopic results help understand the influence of chirality in molecular aggregation and unveil the kind of interactions involved between a chiral alcohol and a chiral ketone with large dispersion contributions.

Relevance of tracking the diversity of Escherichia coli pathotypes to reinforce food safety.

Escherichia coli is among the most prevalent food contaminant microorganisms that have evolved, generating variants based on their effects on the host; these include commensals or pathobiont strains. The last classifications of E. coli intestinal pathobionts found in this review are enteroinvasive, enterohemorrhagic, enteropathogenic, enterotoxigenic, diffusely adherent, and enteroaggregative strains. Meanwhile, the most ancestral are enteropathogenic and enteroaggregative, and the most contemporaries are the enterotoxigenic and enteroinvasive strains. These pathobionts have been proposed based on their infective mechanisms, including toxin production, adherence effects, and tissue damage. It is also evidenced that environmental stresses, including bacterial exposition to antibiotics and disinfectants, contribute to this evolution. Therefore, new antibacterial and antivirulence agents are being explored, mainly from natural sources. In this context, this review discusses the diversity of E. coli pathobionts, their participation in foodborne outbreaks, and strategies to survey and control their spread and virulence.

Photoprotection Is Achieved by Photorespiration and Modification of the Leaf Incident Light, and Their Extent Is Modulated by the Stomatal Sensitivity to Water Deficit in Grapevines.

Absorbed energy in excess of that used by photosynthesis induces photoinhibition, which is common in water deficit conditions, resulting in reductions in stomatal conductance. In grapevines, controlled water deficit is a common field practice, but little is known about the impact of a given water shortage on the energy transduction processes at the leaf level in relation to contrasting stomatal sensitivities to drought. Here, we assessed the effect of a nearly similar water deficit condition on four grapevine varieties: Cabernet Sauvignon (CS) and Sauvignon Blanc (SB), which are stomatal sensitive, and Chardonnay (CH) and Carménère (CM), which are less stomatal sensitive, grown in 20 L pots outdoors. Plants were maintained to nearly 94% of field capacity (WW) and 83% field capacity (WD). We have assessed plant water status, photosynthesis (AN), photorespiration, AN vs. PAR, ACi curves, photochemical (qP) and non-photochemical (qN) fluorescence quenching vs. PAR, the photoprotective effectiveness of NPQ (qPd) and light interception by leaves. Photorespiration is important under WD, but to a different extent between varieties. This is related to stomatal sensitivity, maintaining a safe proportion of PSII reaction centres in an open state. Additionally, the capacity for carboxylation is affected by WD, but to a greater extent in more sensitive varieties. As for qN, in WD it saturates at 750 µmol PAR m-2s-1, irrespective of the variety, which coincides with PAR, from which qN photoprotective effectiveness declines, and qP is reduced to risky thresholds. Additionally, that same PAR intensity is intercepted by WD leaves from highly stomatal-sensitive varieties, likely due to a modification of the leaf angle in those plants. Pigments associated with qN, as well as chlorophylls, do not seem to be a relevant physiological target for acclimation.

Torsional chirality and molecular recognition: the homo and heterochiral dimers of thenyl and furfuryl alcohol.

Furfuryl alcohol and thenyl alcohol contain a labile torsional chiral center, producing transiently chiral enantiomers interconverting in the nanosecond time-scale. We explored chiral molecular recognition using the weakly-bound intermolecular dimers of both alcohols, freezing stereomutation. Supersonic jet broadband microwave spectroscopy revealed homo and heterochiral diastereoisomers for each alcohol dimer and the structural characteristics of the clusters. All dimers are primarily stabilized by a moderately intense O-H⋯O hydrogen bond, but differ in the secondary interactions, which introduce additional hydrogen bonds either to the ring oxygen in furfuryl alcohol or to the π ring system in thenyl alcohol. Density-functional calculations (B2PLYP-D3(BJ)/def2-TZVP) show no clear preferences for a particular stereochemistry in the dimers, with relative energies of the order 1-2 kJ mol-1. The study suggests opportunities for the investigation of chiral recognition in molecules with torsional barriers in between transient and permanent interconversion regimes.

The First Stages of Nanomicelle Formation Captured in the Sevoflurane Trimer.

Self-aggregation of sevoflurane, an inhalable, fluorinated anesthetic, provides a challenge for current state-of-the-art high-resolution techniques due to its large mass and the variety of possible hydrogen bonds between monomers. Here we present the observation of sevoflurane trimer by chirped-pulse Fourier transform microwave spectroscopy, identified through the interplay of experimental and computational methods. The trimer (>600 Da), one of the largest molecular aggregates observed through rotational spectroscopy, does not resemble the binding (C-H···O) motif of the already characterized sevoflurane dimer, instead adapting a new binding configuration created predominantly from 17 CH···F hydrogen bonds that resembles a nanomicellar arrangement. The observation of such a heavy aggregate highlights the potential of rotational spectroscopy to study larger biochemical systems in the limit of spectroscopic congestion but also showcases the challenges ahead as the mass of the system increases.