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Low molecular weight hydrogels are made of small molecules that aggregate via noncovalent interactions. Here, comprehensive characterization of the physical and chemical properties of hydrogels made from thioglycolipids of the disaccharides lactose and cellobiose with simple alkyl chains is reported. While thiolactoside hydrogels are robust, thiocellobioside gels are metastable, precipitating over time into fibrous crystals that can be entangled to create pseudo-hydrogels. Rheology confirms the viscoelastic solid nature of these hydrogels with storage moduli ranging from 10–600 kPa. Additionally, thiolactoside hydrogels are thixotropic which is a desirable property for many potential applications. Freeze-fracture electron microscopy of xerogels shows layers ofmore »stacked sheets that are entangled into networks. These structures are unique compared to the fibers or ribbons typically reported for hydrogels. Differential scanning calorimetry provides gel-to-liquid phase transition temperatures ranging from 30 to 80 °C. Prodan fluorescence spectroscopy allows assignment of phase transitions in the gels and other lyotropic phases of high concentration samples. Phase diagrams are estimated for all hydrogels at 1–10 wt% from 5 to ≥ 80 °C. These hydrogels represent a series of interesting materials with unique properties that make them attractive for numerous potential applications.« less

Despite remarkable progress in photoconversion efficiency, the toxicity of lead-based hybrid perovskites remains an important issue hindering their applications in consumer optoelectronic devices, such as solar cells, LED displays, and photodetectors. For that reason, lead-free metal halide complexes have attracted great attention as alternative optoelectronic materials. In this work, we demonstrate that reactions of two aromatic diamines with iodine in hydroiodic acid produced phenylenediammonium (PDA) and N,N-dimethyl-phenylenediammonium (DMPDA) triiodides, PDA(I3)2⋅2H2O and DMPDA(I3)I, respectively. If the source of bismuth was added, they were converted into previously reported PDA(BiI4)2⋅I2 and new (DMPDA)2(BiI6)(I3)⋅2H2O, having band gaps of 1.45 and 1.7 eV, respectively, whichmore »are in the optimal range for efficient solar light absorbers. All four compounds presented organic–inorganic hybrids, whose supramolecular structures were based on a variety of intermolecular forces, including (N)H⋅⋅⋅I and (N)H⋅⋅⋅O hydrogen bonds as well as I⋅⋅⋅I secondary and weak interactions. Details of their molecular and supramolecular structures are discussed based on single-crystal X-ray diffraction data, thermal analysis, and Raman and optical spectroscopy.« less

Abstract Observing in six frequency bands from 27 to 280 GHz over a large sky area, the Simons Observatory (SO) is poised to address many questions in Galactic astrophysics in addition to its principal cosmological goals. In this work, we provide quantitative forecasts on astrophysical parameters of interest for a range of Galactic science cases. We find that SO can: constrain the frequency spectrum of polarized dust emission at a level of Δ β d ≲ 0.01 and thus test models of dust composition that predict that β d in polarization differs from that measured in total intensity; measure themore »correlation coefficient between polarized dust and synchrotron emission with a factor of two greater precision than current constraints; exclude the nonexistence of exo-Oort clouds at roughly 2.9 σ if the true fraction is similar to the detection rate of giant planets; map more than 850 molecular clouds with at least 50 independent polarization measurements at 1 pc resolution; detect or place upper limits on the polarization fractions of CO(2–1) emission and anomalous microwave emission at the 0.1% level in select regions; and measure the correlation coefficient between optical starlight polarization and microwave polarized dust emission in 1° patches for all lines of sight with N H ≳ 2 × 10 20 cm −2 . The goals and forecasts outlined here provide a roadmap for other microwave polarization experiments to expand their scientific scope via Milky Way astrophysics. 37 37 A supplement describing author contributions to this paper can be found at https://simonsobservatory.org/wp-content/uploads/2022/02/SO_GS_Contributions.pdf .« less

A longstanding debate has surrounded the role of the motor system in speech perception, but progress in this area has been limited by tasks that only examine isolated syllables and conflate decision-making with perception. Using an adaptive task that temporally isolates perception from decision-making, we examined an EEG signature of motor activity (sensorimotor μ/beta suppression) during the perception of auditory phonemes, auditory words, audiovisual words, and environmental sounds while holding difficulty constant at two levels (Easy/Hard). Results revealed left-lateralized sensorimotor μ/beta suppression that was related to perception of speech but not environmental sounds. Audiovisual word and phoneme stimuli showedmore »enhanced left sensorimotor μ/beta suppression for correct relative to incorrect trials, while auditory word stimuli showed enhanced suppression for incorrect trials. Our results demonstrate that motor involvement in perception is left-lateralized, is specific to speech stimuli, and it not simply the result of domain-general processes. These results provide evidence for an interactive network for speech perception in which dorsal stream motor areas are dynamically engaged during the perception of speech depending on the characteristics of the speech signal. Crucially, this motor engagement has different effects on the perceptual outcome depending on the lexicality and modality of the speech stimulus.

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On example of the city of Nadym, located in the Yamalo-Nenets Autonomous Area, the authors consider the socio-ecological problems of the development of green, blue and white open urban spaces. The research approach presented in the article is based on the study of a multifaceted complex of urban social and natural systems in their integrated unity, not just as public places, but as biomes — highly integrated urban ecosystems. A posteriori the researchers based on the materials of interviews conducted in 2020 with experts who in different years took part in the study or planned the development of the openmore »urban spaces in Nadym, as well as on the analysis of available publications on this topic and publicly available data. The study found that factors such as the short summer, during which many residents leave the city, as well as the prevalence of freezing temperatures for almost eight months, in fact, transform the green and blue spaces of Nadym into white. This situation indicates the advisability of a more active appeal to the concept of a “winter city” in the development of the city urban environment. The application of the concept principles can be in demand in the process of creating more comfortable living conditions and spatial mobility of the Nadym residents, as well as for developing the recreational opportunities of the city open spaces and integrating them into the natural environment surrounding the city, which in general can be considered as one of the factors for the sustainable development of the city and the formation of post-industrial features in its socio-economic life.« less

A careful selection of organic and inorganic components enables the production of unusual structure types with promising practical properties by facile syntheses. In this paper, we describe novel supramolecular architectures comprising organic adamantane-like divalent building blocks and iodide or polyiodide anions. Highly acidic conditions facilitated the formation of a doubly protonated organic ligand out of 5,7-dimethyl-1,3-diazaadamantane that generates three different crystal structures with inorganic counterions. In these structures, cationic substructures are constructed by transforming neutral organic ligands into [(C 10 N 2 H 20 )I] + or [(C 10 N 2 H 20 )(H 2 O)] 2+ cations, which crystallizemore »with charge-compensating iodine-based anions of different complexities. All three crystal structures are characterized by various noncovalent forces, ranging from strong (N)H⋯I, (O)H⋯I, and (N)H⋯O hydrogen bonds to secondary and weak I⋯I interactions. Raman and diffuse reflectance spectroscopy as well as DFT calculations were employed to describe the electronic structures and optical properties of new supramolecular architectures, with particular attention to the role of non-covalent interactions.« less