Observing polymerization in 2D dynamic covalent polymers.

The quality of crystalline two-dimensional (2D) polymers1-6 is intimately related to the elusive polymerization and crystallization processes. Understanding the mechanism of such processes at the (sub)molecular level is crucial to improve predictive synthesis and to tailor material properties for applications in catalysis7-10 and (opto)electronics11,12, among others13-18. We characterize a model boroxine 2D dynamic covalent polymer, by using in situ scanning tunnelling microscopy, to unveil both qualitative and quantitative details of the nucleation-elongation processes in real time and under ambient conditions. Sequential data analysis enables observation of the amorphous-to-crystalline transition, the time-dependent evolution of nuclei, the existence of 'non-classical' crystallization pathways and, importantly, the experimental determination of essential crystallization parameters with excellent accuracy, including critical nucleus size, nucleation rate and growth rate. The experimental data have been further rationalized by atomistic computer models, which, taken together, provide a detailed picture of the dynamic on-surface polymerization process. Furthermore, we show how 2D crystal growth can be affected by abnormal grain growth. This finding provides support for the use of abnormal grain growth (a typical phenomenon in metallic and ceramic systems) to convert a polycrystalline structure into a single crystal in organic and 2D material systems.

Molecular Graphene Nanoribbon Junctions.

One of the challenges for the realization of molecular electronics is the design of nanoscale molecular wires displaying long-range charge transport. Graphene nanoribbons are an attractive platform for the development of molecular wires with long-range conductance owing to their unique electrical properties. Despite their potential, the charge transport properties of single nanoribbons remain underexplored. Herein, we report a synthetic approach to prepare N-doped pyrene-pyrazinoquinoxaline molecular graphene nanoribbons terminated with diamino anchoring groups at each end. These terminal groups allow for the formation of stable molecular graphene nanoribbon junctions between two metal electrodes that were investigated by scanning tunneling microscope-based break-junction measurements. The experimental and computational results provide evidence of long-range tunneling charge transport in these systems characterized by a shallow conductance length dependence and electron tunneling through >6 nm molecular backbone.

Madrid immigrants' perceptions of urban food environments and their dietary behaviours.

Large cities are home to several groups of immigrants who undergo important changes in their environmental conditions and lifestyles that significantly modify their risk of chronic diseases. Quantitative evidence indicates that both their health and diet worsen over time; much less is known about the qualitative mechanisms that cause these changes. The aim of this article is to understand how immigrants in the city of Madrid perceive the relation between the urban food environment and dietary behaviour. Based on a Social Ecological Framework, we conducted a secondary qualitative analysis derived from data from 41 immigrant residents, collected in eight focus groups (FGs), conducted in two neighbourhoods in the city of Madrid. We identified the following main categories: 1) Transnational identity and dietary behaviour in the neighbourhood; 2) Transitions in dietary behaviour; and 3) Societal/structural factors determining dietary behaviour in the neighbourhood. The participants in the FGs mentioned that they try to maintain traditional dietary customs and perceive that the taste of their typical dishes is better than those of Spanish dishes. Contradictorily, some participants considered their traditional dietary patterns to be less healthy than Mediterranean ones (consuming olive oil, vegetables, fish). Some participants acknowledged having adapted to the latter voluntarily or through dietary negotiations with their children. Immigrant families with two working parents have difficulties cooking homemade food and resort to less healthy options, such as eating fast food or ready-made meals. Due to their low purchasing power, they buy both ethnic products and other products, as well as considering the prices and offers in supermarkets. Our study highlights several structural mechanisms connecting the physical and social urban food environment with dietary behaviours among immigrant residents of a large city.

Modulating Strain in Twisted Pyrene-Fused Azaacenes.

The design and synthesis of strained aromatics provide an additional insight into the relationship between structure and properties. In the last years, several approaches to twist pyrene-fused azaacenes have been developed that allow to introduce twists of different sizes. Herein, we describe the synthesis of a new set of twisted dibenzotetraazahexacenes constituted by fused pyrene and quinoxaline residues that have been distorted by introducing increasingly larger substituents on the quinoxaline residues. Their twisted structure has been demonstrated by single-crystal X-ray diffraction. Furthermore, absorption, fluorescence, electrochemical and theoretical studies shine light on the effects of the substituents and twists on the optoelectronic and redox properties.

Direct C-H Arylation of Dithiophene-Tetrathiafulvalene: Tuneable Electronic Properties and 2D Self-Assembled Molecular Networks at the Solid/Liquid Interface.

Invited for the cover of this issue is the group of Manuel Souto and co-workers at the University of Aveiro and CICECO-Aveiro Institute of Materials. The image depicts the direct C-H arylation of dithiophene-tetrathiafulvalene (DT-TTF) and the self-assembly of DT-TTF-tetrabenzoic acid studied by using scanning tunnelling microscopy. Read the full text of the article at 10.1002/chem.202300572.

Direct C-H Arylation of Dithiophene-Tetrathiafulvalene: Tuneable Electronic Properties and 2D Self-Assembled Molecular Networks at the Solid/Liquid Interface.

Tetrathiafulvalene is among the best known building blocks in molecular electronics due to its outstanding electron-donating and redox properties. Among its derivatives, dithiophene-tetrathiafulvalene (DT-TTF) has attracted considerable interest in organic electronics, owing to its high field-effect mobility. Herein, we report the direct C-H arylation of DT-TTF to synthesise mono- and tetraarylated derivatives functionalised with electron-withdrawing and electron-donating groups in order to evaluate their influence on the electronic properties by cyclic voltammetry, UV-vis spectroscopy and theoretical calculations. Self-assembly of the DT-TTF-tetrabenzoic acid derivative was studied by using scanning tunnelling microscopy (STM) which revealed the formation of ordered, densely packed 2D hydrogen-bonded networks at the graphite/liquid interface. The tetrabenzoic acid derivative can attain a planar geometry on the graphite surface due to van der Waals interactions with the surface and H-bonding with neighbouring molecules. This study demonstrates a simple method for the synthesis of arylated DT-TTF derivatives towards the design and construction of novel π-extended electroactive frameworks.

Expression of Homing Receptors in IgM+IgD+CD27+ B Cells and Their Frequencies in Appendectomized and/or Tonsillectomized Individuals.

BACKGROUND: In humans, blood circulating IgM+IgD+CD27+ B cells are considered analogous to those described in the marginal zone of the spleen and are involved in important immunological processes. The homing receptors they express, and the organs involved in their development (for example, intestinal organs in rabbits) are only partially known. We recently reported that this population is heterogeneous and composed of at least two subsets: one expressing high levels of IgM - IgMhi B cells - and another low levels - IgMlo B cells. OBJECTIVES: To evaluate the expression of homing receptors on IgD+CD27+ IgMhi and IgMlo B cells and quantify their frequencies in blood of control and appendectomized and/or tonsillectomized volunteers. MATERIALS AND METHODS: Using spectral flow cytometry, the simultaneous expression of 12 previously reported markers that differentiate IgMhi B cells and IgMlo B cells and of α4ß7, CCR9, CD22 and CCR10 were evaluated in blood circulating B cells of control and appendectomized and/or tonsillectomized volunteers. RESULTS: The existence of phenotypically defined IgMlo and IgMhi B cell subsets was confirmed. They differentially expressed intestinal homing receptors, and the expression of α4ß7 and CCR9 seems to determine new IgM subpopulations. IgMlo and IgMhi B cells were detected at lower frequencies in the appendectomized and/or tonsillectomized volunteers relative to controls. CONCLUSIONS: Human blood circulating IgD+CD27+ IgMlo and IgMhi B cell subsets differentially express homing receptors, and it is necessary to investigate if mucosal organs are important in their development.

Heat-related first cardiovascular event incidence in the city of Madrid (Spain): Vulnerability assessment by demographic, socioeconomic, and health indicators.

While climate change and population ageing are expected to increase the exposure and vulnerability to extreme heat events, there is emerging evidence suggesting that social inequalities would additionally magnify the projected health impacts. However, limited evidence exists on how social determinants modify heat-related cardiovascular morbidity. This study aims to explore the association between heat and the incidence of first acute cardiovascular event (CVE) in adults in Madrid between 2015 and 2018, and to assess how social context and other individual characteristics modify the estimated association. We performed a case-crossover study using the individual information collected from electronic medical records of 6514 adults aged 40-75 living in Madrid city that suffered a first CVE during summer (June-September) between 2015 and 2018. We applied conditional logistic regression with a distributed lag non-linear model to analyse the heat-CVE association. Estimates were expressed as Odds Ratio (OR) for extreme heat (at 97.5th percentile of daily maximum temperature distribution), compared to the minimum risk temperature. We performed stratified analyses by specific diagnosis, sex, age (40-64, 65-75), country of origin, area-level deprivation, and presence of comorbidities. Overall, the risk of suffering CVE increased by 15.3% (OR: 1.153 [95%CI 1.010-1.317]) during extreme heat. Males were particularly more affected (1.248, [1.059-1.471]), vs 1.039 [0.810-1.331] in females), and non-Spanish population (1.869 [1.28-2.728]), vs 1.084 [0.940-1.250] in Spanish). Similar estimates were found by age groups. We observed a dose-response pattern across deprivation levels, with larger risks in populations with higher deprivation (1.228 [1.031-1.462]) and almost null association in the lowest deprivation group (1.062 [0.836-1.349]). No clear patterns of larger vulnerability were found by presence of comorbidity. We found that heat unequally increased the risk of suffering CVE in adults in Madrid, affecting mainly males and deprived populations. Local measures should pay special attention to vulnerable populations.

An Organic Molecular Nanobarrel that Hosts and Solubilizes C60.

Organic cages have gained increasing attention in recent years as molecular hosts and porous materials. Among these, barrel-shaped cages or molecular nanobarrels are promising systems to encapsulate large hosts as they possess windows of the same size as their internal cavity. However, these systems have received little attention and remain practically unexplored despite their potential. Herein, we report the design and synthesis of a new trigonal prismatic organic nanobarrel with two large triangular windows with a diameter of 12.7 Šoptimal for the encapsulation of C60 . Remarkably, this organic nanobarrel shows a high affinity for C60 in solvents in which C60 is virtually insoluble, providing stable solutions of C60 .

Exercise facilities and the prevalence of obesity and type 2 diabetes in the city of Madrid.

AIMS/HYPOTHESIS: We aimed to study the association between the availability of exercise facilities and the likelihood of obesity and type 2 diabetes in the adult population of Madrid, Spain. METHODS: We analysed the electronic medical records of all 1,270,512 residents of Madrid aged 40-75 years in 2017. Exercise facility availability was defined as the count of exercise facilities in a 1000 m street network buffer around each residential building entrance. Poisson regression with standard errors clustered at census tract level was used to assess prevalence ratios of exercise facility availability tertiles and obesity and type 2 diabetes. We also examined stratified results by tertiles of area-level socioeconomic status (SES) and sex. RESULTS: People living in areas with lower availability of exercise facilities had a higher prevalence of obesity (prevalence ratio [PR] 1.22 [95% CI 1.20, 1.25]) and diabetes (PR 1.38 [95% CI 1.34, 1.43]). We observed effect modification by area-level SES (p<0.001), with stronger associations for residents living in low-SES areas and no association for residents living in high-SES areas. Associations with type 2 diabetes were stronger among women compared with men, while associations with obesity were similar by sex. CONCLUSIONS/INTERPRETATION: People living in areas with low availability of exercise facilities had a higher prevalence of obesity and type 2 diabetes, and this association was strongest in low-SES areas and for women. Understanding the potential role of exercise facilities in driving inequities in obesity and type 2 diabetes prevalence may inform interventions to reduce health inequities.

Inducing Single-Handed Helicity in a Twisted Molecular Nanoribbon.

Molecular conformation has an important role in chemistry and materials science. Molecular nanoribbons can adopt chiral twisted helical conformations. However, the synthesis of single-handed helically twisted molecular nanoribbons still represents a considerable challenge. Herein, we describe an asymmetric approach to induce single-handed helicity with an excellent degree of conformational discrimination. The chiral induction is the result of the chiral strain generated by fusing two oversized chiral rings and of the propagation of that strain along the nanoribbon's backbone.

A Crystalline 1D Dynamic Covalent Polymer.

The synthesis of crystalline one-dimensional polymers provides a fundamental understanding about the structure-property relationship in polymeric materials and allows the preparation of materials with enhanced thermal, mechanical, and conducting properties. However, the synthesis of crystalline one-dimensional polymers remains a challenge because polymers tend to adopt amorphous or semicrystalline phases. Herein, we report the synthesis of a crystalline one-dimensional polymer in solution by dynamic covalent chemistry. The structure of the polymer has been unambiguously confirmed by microcrystal electron diffraction that together with charge transport studies and theoretical calculations show how the π-stacked chains of the polymer generate optimal channels for charge transport.

Evaluation of ontology structural metrics based on public repository data.

The development and application of biological ontologies have increased significantly in recent years. These ontologies can be retrieved from different repositories, which do not provide much information about quality aspects of the ontologies. In the past years, some ontology structural metrics have been proposed, but their validity as measurement instrument has not been sufficiently studied to date. In this work, we evaluate a set of reproducible and objective ontology structural metrics. Given the lack of standard methods for this purpose, we have applied an evaluation method based on the stability and goodness of the classifications of ontologies produced by each metric on an ontology corpus. The evaluation has been done using ontology repositories as corpora. More concretely, we have used 119 ontologies from the OBO Foundry repository and 78 ontologies from AgroPortal. First, we study the correlations between the metrics. Second, we study whether the clusters for a given metric are stable and have a good structure. The results show that the existing correlations are not biasing the evaluation, there are no metrics generating unstable clusterings and all the metrics evaluated provide at least reasonable clustering structure. Furthermore, our work permits to review and suggest the most reliable ontology structural metrics in terms of stability and goodness of their classifications. Availability: http://sele.inf.um.es/ontology-metrics.

Planar and Helical Dinaphthophenazines.

In this study, we report the synthesis of a series of planar and helical dinaphthophenazines by cyclocondensation reactions between the newly developed 9,10-bis((triisopropylsilyl)ethynyl)anthracene-1,2-dione and different diamines. Their optoelectronic and electrochemical properties are studied by ultraviolet-visible (UV-vis) spectroscopy, fluorescence spectroscopy, cyclic voltammetry, and density functional theory calculations.

Food availability and affordability in a Mediterranean urban context: associations by store type and area-level socio-economic status.

OBJECTIVE: Although food environments have been highlighted as potentially effective targets to improve population diets, evidence on Mediterranean food environments is lacking. We examined differences in food availability and affordability in Madrid (Spain) by store type and area-level socio-economic status (SES). DESIGN: Cross-sectional study. Trained researchers conducted food store audits using the validated Nutrition Environment Measures Survey in Stores for Mediterranean contexts (NEMS-S-MED) tool to measure the availability and price of twelve food groups (specific foods = 35). We computed NEMS-S-MED scores and summarised price data with a Relative Price Index (RPI, comparing prices across stores) and an Affordability Index (normalising prices by area-level income). We compared the availability and affordability of 'healthier-less healthy' food pairs, scores between food store types (supermarkets, specialised, convenience stores and others) and area-level SES using ANOVA and multi-level regression models. SETTING: City of Madrid. 2016 and 2019 to cover a representative sample. PARTICIPANTS: Food stores within a socio-economically diverse sample of sixty-three census tracts (n 151). RESULTS: Supermarkets had higher food availability (37·5/49 NEMS-S-MED points), compared to convenience stores (13·5/49) and specialised stores (8/49). Supermarkets offered lower prices (RPI: 0·83) than specialised stores (RPI: 0·97) and convenience stores (RPI: 2·06). Both 'healthy' and 'less healthy' items were more available in supermarkets. We found no differences in food availability or price by area-level SES, but affordability was higher in higher-income areas. CONCLUSIONS: Supermarkets offered higher food availability and affordability for healthy and less healthy food items. Promoting healthy food availability through supermarkets and specialised stores and/or limiting access to convenience stores are promising policy options to achieve a healthier food environment.

Understanding how alcohol environment influences youth drinking: A concept mapping study among university students. / Influencia del entorno en el consumo de alcohol en jóvenes: Un estudio utilizando concept mapping con estudiantes universitarios.

The aim of the study was to identify the environmental factors that influence alcohol consumption, according to university students, and assess the relative importance and the frequency attributed to each factor. A study using Concept Mapping methodology was performed with a sample of nursing students, who participated in two face-to-face data collection sessions. In session 1, a consensus about the environmental aspects that influence their alcohol consumption was obtained. In session 2, the statements obtained were rated according to their relative importance and frequency in alcohol use (1 = minimum; 5 = maximum). Subsequently, all data were analyzed with the RCMAP of the statistical package R 3.6.1.Approximately 60 students participated in each session. Most were women aged 20 to 24. In session 1, a total of 55 statements were obtained and classified into 7 different clusters: Advertising (9 statements); Family environment (4 statements); Social pressure (12 statements); Responsibilities/norms (4 statements); Holidays and leisure time (7 statements); Emotional situations (8 statements); Accessibility (11 statements). Factors related to social pressure, holidays and leisure time, and alcohol accessibility were considered the most important and frequent in alcohol consumption. In contrast, alcohol advertising was considered the least important (mean 2.6 out of 5) and frequent (mean 2.1 out 5) factor. In conclusion, the factors considered most relevant among nursing students match those having more resources allocated for prevention and health promotion, except for alcohol advertising, which was perceived as less important and frequent compared with the other factors.

El objetivo del estudio fue identificar los factores del entorno que influyen en el consumo de alcohol según la perspectiva de estudiantes universitarios, y evaluar la importancia y la frecuencia atribuida a cada factor. Se utilizó la metodología del Concept Mapping con una muestra de estudiantes de enfermería, que participaron en dos sesiones de recogida de datos. En la sesión 1, se obtuvo un consenso sobre los aspectos del entorno que influyen en su consumo de alcohol. En la sesión 2, los ítems obtenidos se clasificaron en función de la importancia y la frecuencia de estos factores en el consumo de alcohol (1 = mínimo; 5 = máximo). Todos los datos se analizaron con el RCMAP del paquete estadístico R 3.6.1.Alrededor de 60 estudiantes participaron en cada sesión. La mayoría eran mujeres de 20 a 24 años. En la sesión 1, se obtuvieron un total de 55 ítems que fueron clasificados en 7 grupos: Publicidad (9 ítems); Ambiente familiar (4 ítems); Presión social (12 ítems); Responsabilidades/normas (4 ítems); Vacaciones y tiempo libre (7 ítems); Situaciones emocionales (8 ítems); Accesibilidad (11 ítems). Los factores relacionados con la presión social, las vacaciones y el tiempo libre y la accesibilidad del alcohol, fueron considerados los más importantes y frecuentes en el consumo de alcohol. Contrariamente, la publicidad del alcohol fue considerada el factor menos importante (media 2,6 sobre 5) y frecuente (media 2,1 sobre 5). En conclusión, los factores considerados más relevantes entre los estudiantes coinciden con los que se destinan más recursos para la prevención y la promoción de la salud, a excepción de la publicidad del alcohol, que se percibió como menos importante y frecuente comparado con los otros factores.

Availability and promotion of alcohol across different outlet typologies and under different area-level socioeconomic status. / Disponibilidad y promoción de alcohol según la tipología de los locales y las condiciones socioeconómicas del área.

We aimed to characterize the availability and promotion of alcohol at alcohol outlets in Madrid and to compare them according to type of outlet and area-level socioeconomic status. We used the OHCITIES instrument to characterise the alcohol outlets in 42 census tracts of Madrid in 2016. We specified alcohol availability as the density of alcohol outlets and the number of alcohol outlets with extended opening hours (12 or more). We registered any type of promotion associated to alcohol outlets that could be perceived from outside the outlet. We calculated and compared proportions of availability and promotion by alcohol outlet (on- and off-premise) using chi-squared and Fisher Exact tests. We estimated the availability and promotion of alcohol densities per census tract according to area-level socioeconomic status. To assess statistical significance, we used Kruskal-Wallis tests. We recorded 324 alcohol outlets, 241 on-premise and 83 off-premise. Most of the outlets had extended opening hours (73.77%) and at least one sign promoting alcohol (89.51%). More on-premise outlets had extended opening hours and higher presence of alcohol promotion than off-premise (p < 0.001). Higher density of alcohol outlets, extended opening hours and presence of alcohol promotion were found in higher socioeconomic areas (all p < 0.001). These results were also observed for on-premise alcohol outlets. Alcohol availability and promotion were associated with alcohol outlets in Madrid. Future alcohol policies regulating the availability and promotion of alcohol should consider outlet types and area-level socioeconomic status.

El objetivo fue caracterizar la disponibilidad y promoción de alcohol asociados a los locales de venta y consumo de alcohol en Madrid, así como explorar las diferencias en su distribución en función de la tipología del local y las características socioeconómicas del área. Se utilizó el instrumento OHCITIES para caracterizar locales situados en 42 secciones censales de Madrid durante 2016. Se registró la densidad de locales y el número de locales con amplios horarios de apertura (12 o más horas). Se registró cualquier tipo de promoción asociada al local visible desde el exterior. Se compararon los porcentajes de características de disponibilidad y promoción asociada a los locales de consumo y venta de alcohol utilizando el test de chi cuadrado y la prueba exacta de Fisher. Se estimó la densidad de disponibilidad y promoción por sección censal y se exploró su distribución en función de las características socioeconómicas del área mediante el test de Kruskal-Wallis. Se registraron 324 locales, 241 de consumo y 83 de venta. La mayoría tenía un horario amplio de apertura (73,77%) y algún elemento promocional (89,51%). Los locales de consumo tenían horarios más amplios de apertura y más elementos promocionales que los de venta (p < 0,001). Se encontraron mayor densidad de locales, amplitud de horarios y elementos promocionales en áreas de nivel socioeconómico alto (todos p < 0,001). La disponibilidad y promoción estuvieron asociadas con los locales de venta y consumo de alcohol en Madrid. Futuras políticas cuyo objetivo sea la prevención del consumo de alcohol deben tener en cuenta la influencia de los tipos de locales y las características socioeconómicas del área en la distribución de la disponibilidad y promoción de alcohol.

Doubling the Length of the Longest Pyrene-Pyrazinoquinoxaline Molecular Nanoribbons.

Molecular nanoribbons are a class of atomically-precise nanomaterials for a broad range of applications. An iterative approach that allows doubling the length of the longest pyrene-pyrazinoquinoxaline molecular nanoribbons is described. The largest nanoribbon obtained through this approach-with a 60 linearly-fused ring backbone (14.9 nm) and a 324-atoms core (C276 N48 )-shows an extremely high molar absorptivity (values up to 1 198 074 M-1 cm-1 ) that also endows it with a high molar fluorescence brightness (8700 M-1 cm-1 ).

An Expanded 2D Fused Aromatic Network with 90-Ring Hexagons.

Two-dimensional fused aromatic networks (2D FANs) have emerged as a highly versatile alternative to holey graphene. The synthesis of 2D FANs with increasingly larger lattice dimensions will enable new application perspectives. However, the synthesis of larger analogues is mostly limited by lack of appropriate monomers and methods. Herein, we describe the synthesis, characterisation and properties of an expanded 2D FAN with 90-ring hexagons, which exceed the largest 2D FAN lattices reported to date.

Twisted Molecular Nanoribbons with up to 53 Linearly-Fused Rings.

The synthesis of three molecular nanoribbons with a twisted aromatic framework is described. The largest one shows a 53 linearly fused rings backbone (12.9 nm) and 322 conjugated atoms in its aromatic core (C296N24S2). This new family of nanoribbons shows extremely high molar absorptivities, reaching 986 100 M-1 cm-1, and red-emitting properties.