Synthesis Of Frameworks Research Articles

Hydrogen‐bond‐regulated mechanochemical synthesis of covalent organic frameworks: cocrystal precursor strategy for confined assembly

Two‐dimensional imine covalent organic frameworks (2D imine‐COFs) are crystalline porous materials with broad application prospects. Despite the efforts into their design and synthesis, the mechanisms of their formation are still not fully understood. Herein, a one‐pot two‐step mechanochemical cocrystal precursor synthetic strategy is developed for efficient construction of 2D imine‐COFs. The mechanistic investigation demonstrated that the cocrystal precursors of 4,4',4''‐(1,3,5‐triazine‐2,4,6‐triyl)trianiline (TAPT) and p‐toluenesulphonic acid (PTSA) sufficiently regulate the crystalline structure of COF. Evidenced by characterizations and theoretical studies, a helical hydrogen‐bond network was constructed by the N‐H···O supramolecular synthons between amine and sulfate in TAPT‐PTSA, demonstrating the role of cocrystals in promoting the organized stacking of interlayer π‐π interactions, layer arrangement, and interlayer spacing, thus facilitating the orderly assembly of COFs. Moreover, the protonation degree of TAPT amines, which tuned nucleophilic directionality, enabled the sequential progression of intra‐ and interlayer imine condensation reactions, inhibiting the formation of amorphous polymers. The transformation from cocrystal precursors to COFs was achieved through comprehensive control of hydrogen bond and covalent bond sites. This work significantly advances the concept of hydrogen‐bond‐regulated COF assembly and its mechanochemical method in the design and synthesis of 2D imine‐COFs, further elucidating the mechanistic aspects of their mechanochemical synthesis.

Hydrogen-Bond-Regulated Mechanochemical Synthesis of Covalent Organic Frameworks: Cocrystal Precursor Strategy for Confined Assembly.

Two-dimensional imine covalent organic frameworks (2D imine-COFs) are crystalline porous materials with broad application prospects. Despite the efforts into their design and synthesis, the mechanisms of their formation are still not fully understood. Herein, a one-pot two-step mechanochemical cocrystal precursor synthetic strategy is developed for efficient construction of 2D imine-COFs. The mechanistic investigation demonstrated that the cocrystal precursors of 4,4',4''-(1,3,5-triazine-2,4,6-triyl)trianiline (TAPT) and p-toluenesulphonic acid (PTSA) sufficiently regulate the crystalline structure of COF. Evidenced by characterizations and theoretical studies, a helical hydrogen-bond network was constructed by the N-H⋅⋅⋅O supramolecular synthons between amino and sulfonic groups in TAPT-PTSA, demonstrating the role of cocrystals in promoting the organized stacking of interlayer π-π interactions, layer arrangement, and interlayer spacing, thus facilitating the orderly assembly of COFs. Moreover, the protonation degree of TAPT amines, which tuned nucleophilic directionality, enabled the sequential progression of intra- and interlayer imine condensation reactions, inhibiting the formation of amorphous polymers. The transformation from cocrystal precursors to COFs was achieved through comprehensive control of hydrogen bond and covalent bond sites. This work significantly advances the concept of hydrogen-bond-regulated COF assembly and its mechanochemical method in the design and synthesis of 2D imine-COFs, further elucidating the mechanistic aspects of their mechanochemical synthesis.

Automating Pruning in Top-Down Enumeration for Program Synthesis Problems with Monotonic Semantics

In top-down enumeration for program synthesis, abstraction-based pruning uses an abstract domain to approximate the set of possible values that a partial program, when completed, can output on a given input. If the set does not contain the desired output, the partial program and all its possible completions can be pruned. In its general form, abstraction-based pruning requires manually designed, domain-specific abstract domains and semantics, and thus has only been used in domain-specific synthesizers. This paper provides sufficient conditions under which a form of abstraction-based pruning can be automated for arbitrary synthesis problems in the general-purpose Semantics-Guided Synthesis (SemGuS) framework without requiring manually-defined abstract domains. We show that if the semantics of the language for which we are synthesizing programs exhibits some monotonicity properties, one can obtain an abstract interval-based semantics for free from the concrete semantics of the programming language, and use such semantics to effectively prune the search space. We also identify a condition that ensures such abstract semantics can be used to compute a precise abstraction of the set of values that a program derivable from a given hole in a partial program can produce. These precise abstractions make abstraction-based pruning more effective. We implement our approach in a tool, Moito, which can tackle synthesis problems defined in the SemGuS framework. Moito can automate interval-based pruning without any a-priori knowledge of the problem domain, and solve synthesis problems that previously required domain-specific, abstraction-based synthesizers— e.g., synthesis of regular expressions, CSV file schema, and imperative programs from examples.

In Situ Synthesis of Copper-Based Metal-Organic Frameworks with Ligand Defects for Electrochemical Reduction of CO2 into C2 Products.

Electrochemical reduction of CO2 into high-value-added products is a potential approach to solving environmental problems but is limited by poor product selectivity and low efficiency. Metal-organic framework (MOF) materials have been considered one of the most promising catalysts, but their application is limited by complicated preparation processes, especially during the synthesis of organic ligands. In this work, a new three-dimensional Cu-MOF (JXUST-301) with high porosity was constructed based on the naphthalene diimide (NDI) ligand. Furthermore, JXUST-301 with ligand defects (JXUST-301D) originating from the missing NDI unit was synthesized via an in situ reaction. The presence of ligand defects endows JXUST-301D with a better CO2RR performance with a FEC2 of 56.7% and a jC2 of -162.4 mA cm-2. Mechanistic studies revealed that the hierarchical pore structure and amino sites are created from the absence of the NDI unit, which promotes the exposure of catalytically active sites and CO2 enrichment. Furthermore, the electronic structure of the Cu sites is modulated to upshift the d-band center, facilitating chemical adsorption and activation of key reaction intermediates. This work provides new insight into the in situ preparation of efficient Cu-MOF catalysts by introducing defects for the CO2RR.

Rapid yet Controlled Synthesis of 2D Covalent Organic Framework Nanocapsules as High-Performance Photocatalytic Carriers.

Synthesis and assembly of two-dimensional (2D) polymeric materials present a tricky trade-off between the high reaction rate and precise morphology control. Here we report a nanoconfined synthesis of imine-based 2D covalent organic frameworks (COFs) at the interface of oil-in-water (O/W) emulsion droplets stabilized by cationic surfactants. Highly uniform nanocapsules (NCs) could be prepared without adding extra catalysts at room temperature in just 4.5 h at a yield of 86%. The NCs have tunable average diameters and shell thicknesses, depending on the monomer and surfactant types/concentrations. Their BET-specific surface areas are up to 139.0 m2/g, mainly contributedby narrowly-distributed mesopores at ~5.0 nm and micropores at 1.4 nm.The surfactant plays the role of a catalyst during the reaction and interestingly, it also regulates the formation of mesopores and their sizes. Both theoretical and experimental studies confirm that the reaction has been accelerated by two orders of magnitude at the microdroplet interface, compared to that without emulsification. The resulting NCs could be well dispersed in water, and they have been demonstrated to be highly efficient nanocatalystsin application of water-based hydrogen evolution.Such microdroplet interface-confined synthesis may facilitate the future development of 2D polymeric materials for more advanced applications.

Synthesis of dynamic modelling framework and optimal control strategy for virtually coupled train sets with guaranteed safety

Virtual coupling represents a novel railway operational mechanism, wherein several trains share state information and adjust their behaviours based on control objectives, which include safety (collision avoidance) assurance and stability (uniform velocity and constant spacing between trains) maintenance. However, the conflict between safety and stability requirements becomes more apparent, as the closer spacing between trains. Moreover, the hybrid nature of the train platoon operation, which involves both discrete events and continuous dynamics, also poses a significant barrier to the control strategy synthesis. This paper presents the Virtually Coupled Train Sets (VCTS) dynamic modelling framework and strategy synthesis approach to address these problems. A Hybrid Markov Decision Process (HMDP) is adopted for relative longitudinal dynamics modelling of trains, considering the influence of the uncertainty dynamic of trains ahead. A Stackelberg game-based strategy synthesis algorithm is applied for the safe guarantee by overcoming the uncertainty, and a Q-learning method is used for stability strategy selection from the safe strategy. The results showed a 17.95% expansion in the safe state space when compared to the general relative braking scheme (which assumes maximal acceleration during the delay horizon). In a four-train tracking operation scenario, compared with Q-learning without safe constraints, our approach gives similar stability performance; compared with Q-learning with general relative braking safe constraints, our approach not only assurance safety but has a better stability performance.

How Could We Establish Monitoring and Surveillance of Health-Harming Corporations and Can Governments Be Trusted to Do It? Comment on "National Public Health Surveillance of Corporations in Key Unhealthy Commodity Industries – A Scoping Review and Framework Synthesis"

In the context of growing interest in the commercial determinants of health (CDOH) which has been defined as "the systems, practices, and pathways through which commercial actors drive health and equity," Bennett et al propose that governments implement monitoring of unhealthy commodity industries (UCIs) (including tobacco, alcohol, and ultra-processed foods) as part of their routine public health surveillance. We explore the evidence underpinning that suggestion and provide details on how corporate monitoring might be practically implemented drawing on lessons from tobacco industry monitoring which has been an established part of tobacco control. While governments should actively support such an approach as part of efforts to address commercially driven health harms, we urge caution in governments undertaking monitoring and identify significant barriers to implementation, while also suggesting ways in which those barriers might be overcome.

Controllable synthesis and multiple applications of multi-color sp2c-covalent organic frameworks based on side-chain regulation

Controllable synthesis and multiple applications of multi-color sp2c-covalent organic frameworks based on side-chain regulation

Topology-driven directed synthesis of metal-organic frameworks

Topology-driven directed synthesis of metal-organic frameworks

A novel barium zirconate titanate/Fe-MOF nanocomposite: Synthesis, characterization, and photocatalytic mechanism

The synthesis of a metal-organic framework (MOF) matrix of MIL-100 (Fe) loaded with BaTi0.85Zr0.15O3 (BTZ) nanoparticles (NPs) was achieved by an easy one-pot solvothermal procedure and encasing of BTZ NPs. X-ray diffraction (XRD), photoluminescence spectroscopy (PL), UV-Vis reflectance spectroscopy (DRS), Transmission electron microscopy (TEM), scanning electron microscopy (SEM), and N2 adsorption-desorption were deployed for the characterization of the synthesized samples. The degradation efficiency for tetracycline (TC), among the photocatalytic BTZ/MIL-100(Fe) nanocomposites with varied BTZ percentages (10, 20, 30, and 40 wt% BTZ), revealed that (30 wt%), offered the best outcome. At 0.8 g L-1 of the catalyst, pH 9, 30 ppm TC solution, and 180 min irradiation time, as the optimal conditions, the degradation efficiency of TC molecules reached >90. Based on the study of some scavenging agents, the importance of the reactive species in TC photodegradation followed the trend of photogenerated e-, hydroxyl radicals, superoxide radicals, and photogenerated h+. TC degradation occurred through reduction and oxidation pathways via a direct Z-scheme mechanism. This work aims to describe the use of MOF-based materials as a visible-light-driven photocatalyst towards TC.

Design and synthesis of ladder-type covalent organic frameworks

Design and synthesis of ladder-type covalent organic frameworks

A 1,3,5-triazine μ3-bridged neutral Cu(I) framework with enhanced stability and CO2 capture selectivity

Compounds with 1,3,5-triazine ring such as melamine derivatives, known for their low cost and high stability, offer potential for affordable, stable metal organic framework (MOF) synthesis. However, reported such frameworks are facing issues like low stability and reduced porosity. To overcome such problems, we explored organic ligands with protonated nitrogen atoms on the 1,3,5-triazine ring, facilitated by introducing hydroxyl groups on carbon atoms of the triazine ring to construct MOFs. By using 5-azacytosine, we have successfully synthesized SXU-121, a neutral ultramicroporous MOF with eta-topology and high density of open Cu(I) sites. SXU-121 features robust structural stability and significant CO2 adsorption capacity with high selectivity over N2 under ambient conditions. We believe SXU-121's development opens new avenues for creating a class of stable and low cost metal-triazine frameworks with potential diverse functionalities.

Interventions to reduce racial/ethnic disparities across the breast cancer care continuum.

160 Background: In the United States, racial/ethnic disparities in adoption of breast cancer evidence-based practices (EBPs) persist along the cancer care continuum. This scoping review applied an implementation science lens to describe the current evidence base for interventions to reduce disparities, synthesizing evidence on effective interventions while highlighting gaps in the literature. Methods: A formalized search strategy identified USA-based interventional studies aiming to improve adoption of an EBP along the breast cancer care continuum among racially/ethnically minoritized patients. Relevant articles from 1/2010 - 8/2022 (Medline, Embase, Cochrane, and Scopus) were included. For each article, two reviewers screened and extracted data, with a third resolving discrepancies. The PRISMA-ScR checklist and JBO Manual for Evidence Synthesis framework were followed. Results: Our search strategy yielded 45,215 articles. After applying inclusion/exclusion criteria, 59 articles were retained, targeting screening (85%, 50 of 59), treatment (12%, 7 of 59), and survivorship (5%, 3 of 59) (2 targeted multiple areas). No articles targeted end-of-life care. Of these, 49% (29 of 59) were randomized controlled trials (RCTs). Among 24 screening RCTs, the most common interventions—and fraction with statistically significant improved screening uptake—were patient navigation (100%, 11 of 11) and patient education (80%, 4 of 5). Among 4 treatment RCTs, 3 targeted adjuvant chemotherapy uptake. Of these, 1 had significant improvements and used patient navigation. The 2 studies without significant improvements used a patient tracking tool/alert system or patient education. Among 2 survivorship RCTs, one used email interventions, resulting in significantly improved physical activity and dietary health. A second used a nurse-facilitated internet support group, resulting in significantly improved physical/psychological symptoms. Early to mid-stage implementation outcomes (acceptability, adoption, appropriateness, feasibility, or fidelity) were commonly measured (81%, 48 of 59). No study measured later stage implementation outcomes (sustainability or costs). Conclusions: In multiple studies, patient navigation and education improved breast cancer screening among racially/ethnically minoritized populations. In one study, patient navigation improved completion of adjuvant treatment. Despite these studies, patient navigation is not reimbursed for cancer screening, and adoption has not been widespread. Future studies should focus on evaluating and improving later stage implementation outcomes (sustainability and costs). Based on these results, insurance reimbursement mechanisms for screening-related navigation may be warranted. Future breast cancer care delivery disparities research should also be expanded to include treatment, survivorship, and end-of-life care.

PERF: Panoramic Neural Radiance Field From a Single Panorama.

Neural Radiance Field (NeRF) has achieved substantial progress in novel view synthesis given multi-view images. Recently, some works have attempted to train a NeRF from a single image with 3D priors. They mainly focus on a limited field of view with a few occlusions, which greatly limits their scalability to real-world 360-degree panoramic scenarios with large-size occlusions. In this paper, we present PERF, a 360-degree novel view synthesis framework that trains a panoramic neural radiance field from a single panorama. Notably, PERF allows 3D roaming in a complex scene without expensive and tedious image collection. To achieve this goal, we propose a novel collaborative RGBD inpainting method and a progressive inpainting-and-erasing method to lift up a 360-degree 2D scene to a 3D scene. Specifically, we first predict a panoramic depth map as initialization given a single panorama and reconstruct visible 3D regions with volume rendering. Then we introduce a collaborative RGBD inpainting approach into a NeRF for completing RGB images and depth maps from random views, which is derived from an RGB Stable Diffusion model and a monocular depth estimator. Finally, we introduce an inpainting-and-erasing strategy to avoid inconsistent geometry between a newly-sampled view and reference views. The two components are integrated into the learning of NeRFs in a unified optimization framework and achieve promising results. Extensive experiments on Replica and a new dataset PERF-in-the-wild demonstrate the superiority of our PERF over state-of-the-art methods. Our PERF can be widely used for real-world applications, such as panorama-to-3D, text-to-3D, and 3D scene stylization applications.

Barriers and Facilitators for Physical Activity Among Children and Youth With Autism-A Scoping Review.

The purpose of this scoping review was to systematically synthesize barriers and facilitators for physical activity (PA) among children and youth with autism spectrum disorders (ASD) across the socioecological model. Five electronic databases were searched in March 2022 for studies examining barriers and facilitators for PA among children and youth with ASD. An updated search was performed in April 2024. The framework synthesis method was utilized, and the socioecological model was the chosen framework. Fifty-four studies published from 2008 to 2024 were included. Among the included studies, 57% included the perspectives of children and youth with ASD alone or together with proxies (eg,parents, teachers, and coaches), while 43% included only the perspectives of proxies. Barriers and facilitators on the intrapersonal and interpersonal levels were most substantial. The analysis led to 2 main categories of barriers and facilitators, those unique to children and youth with ASD, and those similar to what had been identified through research on children and youth, both typically developing and with other disabilities. This comprehensive scoping review shows the complexity of factors contributing to barriers and facilitators for PA among children and youth with ASD, and highlights both the factors unique to this population and more general factors affecting PA participation. The findings from this synthesis might be used to guide the development of inclusive PA in physical education, organized sports, and other community PA arenas.

Microwave-Assisted One-Step Synthesis of Palladium-Encapsulated Covalent Organic Frameworks for Heterogeneous Catalysis.

Metal-encapsulated covalent organic framework (metal/COF) represents an emerging paradigm in heterogeneous catalysis. However, the time-intensive (usually 4 or more days) and tedious multi-step synthesis of metal/COFs remains a significant stumbling block for their broad application. To address this challenge, we introduce a facile microwave-assisted in situ metal encapsulation strategy to cooperatively combine COF formation and in situ palladium(II) encapsulation in one step. With this unprecedented approach, we synthesize a diverse range of palladium(II)-encapsulated COFs (termed Mw-Pd/COF) in the air within just an hour. Notably, this strategy is scalable for large-scale production (~0.5 g). Leveraging the high crystallinity, porosity, and structural stability, one representative Mw-Pd/COF exhibits remarkable activity, functional group tolerance, and recyclability for the Suzuki-Miyaura coupling reaction at room temperature, surpassing most previously reported Pd(II)/COF catalysts with respect to catalytic performance, preparation time, and synthetic ease. This microwave-assisted in situ metal encapsulation strategy opens a facile and rapid avenue to construct metal/COF hybrids, which hold enormous potential in a multitude of applications including heterogeneous catalysis, sensing, and energy storage.

Exploring the contribution of cancer palliative care development toward alleviating the human crisis of suffering in low- and middle-income countries: A framework synthesis protocol.

Inadequate access to cancer care, high mortality, and out-of-pocket expenditure contribute to health-related suffering in low- and middle-income countries, making palliative care a relevant option. How palliative care development has alleviated suffering is not systematically studied, necessitating this review's conduct. The objective of this systematic review with a framework synthesis approach is to identify and map the dimensions and indicators of cancer palliative care development and the components of integration between cancer and palliative care in LMICs. Uni- and multi-disciplinary databases like Cochrane, MEDLINE (PubMed), EMBASE, CINAHL Complete, and PsycINFO will be systematically searched for eligible studies exploring cancer palliative care development in LMICs and their contribution to alleviating health-related suffering in the cancer context. Our selection process will encompass countries classified by the World Bank as low-income (26 countries), lower-income (54 countries), and upper-middle-income (54 countries). Review findings will be synthesised and analysed using a best-fit framework synthesis method using 2 frameworks (the WHO model of components and indicators for palliative care development and integration elements between oncology and palliative care), and the findings will be developed as themes and subthemes, and patterns interpreted using these 2 models. This review will analyse the development of cancer palliative care in LMICs. It will identify gaps in provision, solutions derived at the regional level to address them, and best practices and failed models with reasons underpinning them.

Encapsulating Azolates Within Cationic Metal-Organic Frameworks for High-Energy-Density Materials.

Despite the synthesis of numerous cationic metal-organic frameworks (CMOFs), their counter anions have been primarily limited to inorganic Cl-, NO3 -, ClO4 -, BF4 -, and Cr2O7 2-, which have weak coordination abilities. In this study, a series of new CMOFs is synthesized using azolates with strong coordination abilities as counter anions, which are exclusively employed as ligands for coordinating with metals. Owing to the unique nitrogen-rich composition of azolates, the CMOFs demonstrate significant potential as high-energy-density materials. Notably, CMOF(CuTNPO) has an exceptionally high heat of detonation of 7375kJ kg-1, surpassing even that of the state-of-art CL-20 (6536kJ kg-1). To further validate the advantages of employing azolates as counter anions, analogues with azolates serving as ligands are also synthesized. The comparison study indicates that encapsulating azolates within the cationic frameworks confers both high energy and safety properties. X-ray data and quantum calculations indicate that their enhanced performance stems from stronger H─bonds and π-π interactions. This study introduces new roles for azolates in MOFs and expands possibilities for structural diversity and potential applications of framework materials.

Synthesis and investigation of charge storage characteristics in Ni-MOF/PANI composite as an active electrode material for supercapacitor

This study aimed to develop a more stable and efficient energy storage device, synthesis of nickel-based pristine metal organic framework (MOF) and combined it with the emeraldine base phase of polyaniline (PANI) which is confirmed with XRD, SEM and TEM. Both Ni-MOF and PANI exhibit faradaic (battery-like) behaviour. However, when these two materials are combined, the stability of the resulting material is enhanced. The initial materials, MOF and PANI, exhibit specific capacities of 42 C/g and 72 C/g, respectively. However, when these two materials are combined, their composite exhibits an enhanced specific capacity of 122 C/g. The cyclic voltammetry (CV) analysis shows oxidation and reduction peaks, indicating faradaic behaviour. This behaviour is further confirmed by electrochemical impedance spectroscopy (EIS). Upon comparing it with prior results, the specific capacity appears to be slightly lower. However, it is anticipated to exhibit stronger stability, which is contradictory. The composite material (Ni-MOF/PANI) exhibits remarkable capacitive retention of 99.25 % even after undergoing 5000 cycles, as anticipated. In order to validate the aforementioned findings and determine the extent of the current contribution from capacitive and diffusive control, Dunn's model was employed. The data demonstrates the prevalence of diffusive-controlled (faradaic) current over capacitive current. The highest proportion of current resulting from diffusion is 96 %, achieved at a scan rate of 5 mV/s. The highest proportion of current resulting from capacitance is 24 %, achieved at a scan rate of 300 mV/s. At lower scan rates, the material exhibits a greater faradaic behaviour, whereas at higher scan rates, there is a progressive increase in non-faradaic processes. The insufficient time for diffusive process at higher scan rates is the cause. The Dunn's model with quadratic correction is also performed and comparative results were shown. Overall, the material exhibits more stability and dominance in the faradaic process, which paves the path for improved performance.

Human resources for health: a framework synthesis to put health workers at the centre of healthcare

BackgroundHuman resources are a key determinant for the quality of healthcare and health outcomes. Several human resource management approaches or practices have been proposed and implemented to better understand and...