Triply periodic minimal surface structures and related geometries are widely identified in many natural systems, such as biological membranes and biophotonic structures in butterfly‐wing scales. ...Inspired by their marvelous and highly symmetrical structures and optimized physical properties, these structures have sparked immense interest for creating novel materials by extracting the design from nature. Significant progress has been made to understand these biological structures and fabricate artificial materials by top‐down and bottom‐up approaches for numerous applications in chemistry and materials science. Herein, research achievements, including theoretical and experimental discoveries, in both biological systems and the artificial synthesis of materials with triply periodic minimal surface structures and related materials are summarized. Recent developments in self‐assembled lyotropic liquid crystal phases, block copolymer systems, and their inorganic replicas are discussed in detail.
Triply periodic minimal surfaces and related materials have attracted great attention due to their highly symmetrical structures and optimized properties. The formation, properties, and applications of related materials in natural and artificial systems are summarized. Lyotropic liquid‐crystal phases, block copolymer systems, and their inorganic replicas are emphasized and discussed in detail.
Three Cu(I) coordination networks, namely, {Cu2(bpz)2(CN)X·CH3CN} n , (X = Cl, 1; I, 3), {Cu6(bpz)6(CH3CN)3(CN)3Br·2OH·14CH3CN} n , (2, bpz = 3,3′,5,5′-tetramethyl-4,4′-bipyrazole), were ...prepared by using solvothermal method. The cyanide ligands in these networks were generated in situ by cleavage of C–C bond of MeCN under solvothermal condition. The structures of these networks are dependent on halogen anions. Complex 1 is a ladderlike structure with μ2-CN– as rung and μ2-bpz as armrest. The Cl– in 1 is at terminal position but does not extend the one-dimensional (1D) ladder to higher dimensionalities. Complex 2 is a three-dimensional (3D) framework comprised of novel planar Cu3Br triangle and single Cu nodes, which are extended by μ2-bpz and μ2-CN– to form a novel (3,9)-connected gfy network. Density functional theory calculations showed that single-electron delocalization of Br atom induces the plane structure of Cu3Br. Complex 3 also possesses a similar ladderlike subunit as in 1, but the I– acts as bidentate bridge to extend the ladder to 3D framework with a four-connected sra topology. The three networks show notable catalytic activity on the click reaction. The compared catalytic results demonstrate that complex 2 possesses the best catalysis performance among three complexes, which is ascribed to the largest solvent-accessible void (porosity: 2 (29.4%) > 1 (25.7%) > 3 (17.6%)) and the more Cu(I) active sites in 2. The present combined structure–property studies provide not only a new synthetic route to obtain a new kind of catalyst for click reaction but also the new insights on catalyst structure–function relationships.
Goal-driven and feedforward-only convolutional neural networks (CNN) have been shown to be able to predict and decode cortical responses to natural images or videos. Here, we explored an alternative ...deep neural network, variational auto-encoder (VAE), as a computational model of the visual cortex. We trained a VAE with a five-layer encoder and a five-layer decoder to learn visual representations from a diverse set of unlabeled images. Using the trained VAE, we predicted and decoded cortical activity observed with functional magnetic resonance imaging (fMRI) from three human subjects passively watching natural videos. Compared to CNN, VAE could predict the video-evoked cortical responses with comparable accuracy in early visual areas, but relatively lower accuracy in higher-order visual areas. The distinction between CNN and VAE in terms of encoding performance was primarily attributed to their different learning objectives, rather than their different model architecture or number of parameters. Despite lower encoding accuracies, VAE offered a more convenient strategy for decoding the fMRI activity to reconstruct the video input, by first converting the fMRI activity to the VAE's latent variables, and then converting the latent variables to the reconstructed video frames through the VAE's decoder. This strategy was more advantageous than alternative decoding methods, e.g. partial least squares regression, for being able to reconstruct both the spatial structure and color of the visual input. Such findings highlight VAE as an unsupervised model for learning visual representation, as well as its potential and limitations for explaining cortical responses and reconstructing naturalistic and diverse visual experiences.
•Variational auto-encoder implements 1 an unsupervised model of “Bayesian brain”.•Variational auto-encoder explains and predicts fMRI responses to natural videos.•Variational auto-encoder decodes fMRI responses to directly reconstruct visual input.•Convolutional neural networks trained for image classification better predict fMRI responses than variational auto-encoder trained for image reconstruction.
The Microgeography of Housing Supply Baum-Snow, Nathaniel; Han, Lu
The Journal of political economy,
06/2024, Letnik:
132, Številka:
6
Journal Article
Recenzirano
We perform a comprehensive neighborhood-level analysis of housing supply. Predictions of floor space and housing unit supply elasticities using our estimates average 0.5 and 0.3 across all urban ...neighborhoods in the United States, exhibiting greater variation within than between metro regions. New construction accounts for about 50% of unit supply responses, with important additional roles for teardowns and renovations. Supply responses grow with central business district distance mostly from the increasing availability of undeveloped land, flatter land, and less regulation. Identification comes from variation in labor demand shocks to commuting destinations, as aggregated using insights from a quantitative spatial equilibrium model.
Adhesive hydrogels are widely applied for biological and medical purposes; however, they are generally unable to adhere to tissues under wet/underwater conditions. Herein, described is a class of ...novel dynamic hydrogels that shows repeatable and long‐term stable underwater adhesion to various substrates including wet biological tissues. The hydrogels have Fe3+‐induced hydrophobic surfaces, which are dynamic and can undergo a self‐hydrophobization process to achieve strong underwater adhesion to a diverse range of dried/wet substrates without the need for additional processes or reagents. It is also demonstrated that the hydrogels can directly adhere to biological tissues in the presence of under sweat, blood, or body fluid exposure, and that the adhesion is compatible with in vivo dynamic movements. This study provides a novel strategy for fabricating underwater adhesive hydrogels for many applications, such as soft robots, wearable devices, tissue adhesives, and wound dressings.
Underwater adhesion is achieved through a self‐hydrophobization process on a dynamic hydrogel surface. The adhesion mechanism ensures ready, strong, nonspecific, repeatable, and long‐term stable underwater adhesion without requiring extra processes or reagents, which enables convenient application underwater/or in wet conditions.
routine frailty identification and management is national policy in England, but there remains a lack of evidence on the impact of frailty on healthcare resource use. We evaluated the impact of ...frailty on the use and costs of general practice and hospital care.
retrospective longitudinal analysis using linked routine primary care records for 95,863 patients aged 65-95 years registered with 125 UK general practices between 2003 and 2014. Baseline frailty was measured using the electronic Frailty Index (eFI) and classified in four categories (non, mild, moderate, severe). Negative binomial regressions and ordinary least squares regressions with multilevel mixed effects were applied on the use and costs of general practice and hospital care.
compared with non-frail status, annual general practitioner consultation incidence rate ratios (IRRs) were 1.24 (95% CI: 1.21-1.27) for mild, 1.41 (95% CI: 1.35-1.47) for moderate, and 1.52 (95% CI: 1.42-1.62) for severe frailty. For emergency hospital admissions, the respective IRRs were 1.64 (95% CI 1.60-1.68), 2.45 (95% CI 2.37-2.53) and 3.16 (95% CI: 3.00-3.33). Compared with non-frail people the IRR for inpatient days was 7.26 (95% CI 6.61-7.97) for severe frailty. Using 2013/14 reference costs, extra annual cost to the healthcare system per person was £561.05 for mild, £1,208.60 for moderate and £2,108.20 for severe frailty. This equates to a total additional cost of £5.8 billion per year across the UK.
increasing frailty is associated with substantial increases in healthcare costs, driven by increased hospital admissions, longer inpatient stay, and increased general practice consultations.
Although asymmetric C−H functionalization has been available for the synthesis of structurally diverse molecules, catalytic dynamic kinetic resolution (DKR) approaches to change racemic stereogenic ...axes remain synthetic challenges in this field. Here, a concise palladium‐catalyzed DKR was combined with C−H functionalization involving olefination and alkynylation for the highly efficient synthesis of non‐biaryl‐atropisomer‐type (NBA) axially chiral oragnosilanes. The chemistry proceeded through two different and distinct DKR: first, an atroposelective C−H olefination or alkynylation produced axially chiral vinylsilanes or alkynylsilanes as a new family of non‐biaryl atropisomers (NBA), and second, the extension of this DKR strategy to twofold o,o′‐C−H functionalization led to the multifunctional axially chiral organosilicon compounds with up to >99 % ee.
Powerful DKR: A palladium‐catalyzed atroposelective ortho C−H olefination/alkynylaton combined with dynamic kinetic resolution strategy is developed to construct axially chiral styrene‐type organosilanes with excellent enantioselectivities.
Objective: To detect the potential association between dietary live microbe and cardiovascular diseases (CVD). Methods: Data of 10,875 participants aged 18 years or older in this study were collected ...from the National Health and Nutrition Examination Survey (NHANES). Participants in this study were divided into three groups according to the Sanders dietary live microbe classification system: low, medium, and high dietary live microbe groups. CVD was defined by a combination of self-reported physician diagnoses and standardized medical status questionnaires. The analyses utilized weighted logistic regression models. Results: After the full adjustment for confounders, patients in the medium dietary live microbe group had a low prevalence of CVD in contrast to those in the low dietary live microbe group (OR: 0.78, 95% CI: 0.52−0.99, and p < 0.05), but no significant association with CVD was detected between the high and low dietary live microbe groups. Higher dietary live microbe groups were negatively associated with the prevalence of stroke (p for trend = 0.01) and heart attack (p for trend = 0.01). People who were male were more likely to suffer stroke due to low dietary live microbe (p for interaction = 0.03). Conclusion: A high dietary live microbe intake was associated with a low prevalence of CVD, and the significant association was detected when the analysis was limited to stroke and heart attack.
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