Precise Architecture Research Articles

Ultra‐High Metal‐Ion Selectivity Induced by Intramolecular Cation‐π Interactions for the One‐Pot Synthesis of Precise Heterometallic Architectures

AbstractHeterometallic supramolecules, known for their unique synergistic effects, have shown broad applications in photochemistry, host‐guest chemistry, and catalysis. However, there are great challenges to precisely construct heterometallic supramolecules rather than a statistical mixture, due to the limited metal‐ion selectivity of coordination units. In particular, heterometallic architectures precisely encoded with different metal ions usually fail to form in a one‐pot method when only one type of coordinated motif exists due to its poor metal‐ion selectivity. Herein, we propose an effective intramolecular cation‐π (ICπ) strategy and successfully constructed the heterometallic supramolecule Zn2Cu4L34 by the one‐pot self‐assembly of tritopic terpyridyl ligand L3 with Zn(II) and Cu(II), following a clear self‐assembly mechanism in which only thermodynamic dimers ZnL12 and Cu2L22 were constructed with model ligands L1, L2, Zn(II) and Cu(II) with perfect self‐sorting and an ultra‐high metal‐selectivity feature. The successful construction of the heterometallic supramolecule Zn2Cu4L34, in which the definite sequence of metal ions Zn(II) and Cu(II) is encoded in the one‐pot method, will offer a novel approach to precisely construct heterometallic architectures.

Ultra-High Metal-Ion Selectivity Induced by Intramolecular Cation-π Interactions for the One-Pot Synthesis of Precise Heterometallic Architectures.

Heterometallic supramolecules, known for their unique synergistic effects, have shown broad applications in photochemistry, host-guest chemistry, and catalysis. However, there are great challenges to precisely construct heterometallic supramolecules rather than a statistical mixture, due to the limited metal-ion selectivity of coordination units. In particular, heterometallic architectures precisely encoded with different metal ions usually fail to form in a one-pot method when only one type of coordinated motif exists due to its poor metal-ion selectivity. Herein, we propose an effective intramolecular cation-π (ICπ) strategy and successfully constructed the heterometallic supramolecule Zn2Cu4L34 by the one-pot self-assembly of tritopic terpyridyl ligand L3 with Zn(II) and Cu(II), following a clear self-assembly mechanism in which only thermodynamic dimers ZnL12 and Cu2L22 were constructed with model ligands L1, L2, Zn(II) and Cu(II) with perfect self-sorting and an ultra-high metal-selectivity feature. The successful construction of the heterometallic supramolecule Zn2Cu4L34, in which the definite sequence of metal ions Zn(II) and Cu(II) is encoded in the one-pot method, will offer a novel approach to precisely construct heterometallic architectures.

Transcriptome-wide splicing network reveals specialized regulatory functions of the core spliceosome.

The spliceosome is the complex molecular machinery that sequentially assembles on eukaryotic messenger RNA precursors to remove introns (pre-mRNA splicing), a physiologically regulated process altered in numerous pathologies. We report transcriptome-wide analyses upon systematic knock down of 305 spliceosome components and regulators in human cancer cells and the reconstruction of functional splicing factor networks that govern different classes of alternative splicing decisions. The results disentangle intricate circuits of splicing factor cross-regulation, reveal that the precise architecture of late-assembling U4/U6.U5 tri-small nuclear ribonucleoprotein (snRNP) complexes regulates splice site pairing, and discover an unprecedented division of labor among protein components of U1 snRNP for regulating exon definition and alternative 5' splice site selection. Thus, we provide a resource to explore physiological and pathological mechanisms of splicing regulation.

Resolving complex duplication variants in autism spectrum disorder using long-read genome sequencing.

Rare or de novo structural variation, primarily in the form of copy number variants, is detected in 5%-10% of autism spectrum disorder (ASD) families. While complex structural variants involving duplications can generally be detected using microarray or short-read genome sequencing (GS), these methods frequently fail to characterize breakpoints at nucleotide resolution, requiring additional molecular methods for validation and fine-mapping. Here, we use Oxford Nanopore Technologies PromethION long-read GS to characterize complex genomic rearrangements (CGRs) involving large duplications that segregate with ASD in five families. In total, we investigated 13 CGR carriers and were able to resolve all breakpoint junctions at nucleotide resolution. While all breakpoints were identified, the precise genomic architecture of one rearrangement remained unresolved with three different potential structures. The findings in two families include potential fusion genes formed through duplication rearrangements, involving IL1RAPL1-DMD and SUPT16H-CHD8 In two of the families originating from the same geographical region, an identical rearrangement involving ANK2 was identified, which likely represents a founder variant. In addition, we analyze methylation status directly from the long-read data, allowing us to assess the activity of rearranged genes and regulatory regions. Investigation of methylation across the CGRs reveals aberrant methylation status in carriers across a rearrangement affecting the CREBBP locus. In aggregate, our results demonstrate the utility of nanopore sequencing to pinpoint CGRs associated with ASD in five unrelated families, and highlight the importance of a gene-centric description of disease-associated complex chromosomal rearrangements.

Dental Caries Segmentation using Deformable Dense Residual Half U-Net for Teledentistry System

Clinical practitioners’ workload and challenges are significantly reduced by classifying, predicting, and localizing lesions or dental caries. In recent research, a high-reliability diagnostic system within deep learning models has been implemented in a clinical teledentistry system. In order to construct an efficient, precise, and lightweight deep learning architecture, it is dynamically structured. In this paper, we present an efficient, accurate, and lightweight deep learning architecture for augmenting spatial locations and improving the transformation modeling abilities of fixed-structure CNNs. Deformable Dense Residual (DDR) enhances the efficacy of the residual convolution block by optimizing its structure, thereby mitigating model redundancy and ameliorating the challenge of vanishing gradients encountered during the training stages. DDR Half U-Net presents notable advancements to the simplified U-Net framework across three pivotal domains: the encoder, decoder, and loss function. Specifically, the encoder integrates deformable convolutions, thereby enhancing the model's capacity to discern features of diverse scales and configurations. In the decoder, a sophisticated arrangement of dense residual connections facilitates the fusion of low-level and high-level features, contributing to comprehensive feature extraction. Moreover, the utilization of a weight-adaptive loss function ensures equitable consideration of both caries and non-caries samples, thereby promoting balanced optimization during training.

A versatile 5-axis melt electrowriting platform for unprecedented design freedom of 3D fibrous scaffolds

Melt electrowriting (MEW) is an electrohydrodynamic additive manufacturing technology for the fabrication of precise microfiber scaffold architectures but is so far restricted to printing onto simple collector geometries and, therefore, constrained in design freedom. This is due to current limitations in print head designs, kinematic systems, and software to generate motion commands. We address these aspects by upgrading a low-cost 5-axis kinematic system and complete it with a custom-designed print head and a collector fabrication workflow to enable collision-free MEW onto arbitrarily shaped multicurvature 3D geometries. A universal graphical approach enables generation of Gcodes customized to the 5-axis MEW requirements. The print head is validated by producing polycaprolactone fibers with diameters ranging from 5.6 ± 1.7 µm to 50.7 ± 5.5 µm and by writing both linear and non-linear fiber patterns onto collectors featuring concave and convex surfaces. Stable printing conditions are achieved by continuously reorienting the print head and collector surface perpendicular to each other at a constant working distance. Ultimately, we demonstrate the system’s potential in shaping anatomically relevant scaffold geometries by stacking microfibers onto collectors resembling a trileaflet valve and a bifurcating vessel. This multi-axis MEW platform unlocks exciting avenues towards unprecedented design freedom for MEW scaffolds.

Delineation of the impact on temporal behaviors of off-axis photoemission in an ultrafast electron microscope

Efforts to push the spatiotemporal imaging-resolution limits of femtosecond laser-driven ultrafast electron microscopes (UEMs) to the combined angstrom–fs range will benefit from stable sources capable of generating high bunch charges. Recent demonstrations of unconventional off-axis photoemitting geometries are promising, but connections to the observed onset of structural dynamics are yet to be established. Here we use the in-situ photoexcitation of coherent phonons to quantify the relative time-of-flight (r-TOF) of photoelectron packets generated from the Ni Wehnelt aperture and from a Ta cathode set-back from the aperture plane. We further support the UEM experiments with particle-tracing simulations of the precise electron-gun architecture and photoemitting geometries. In this way, we measure discernible shifts in electron-packet TOF of tens of picoseconds for the two photoemitting surfaces. These shifts arise from the impact that the Wehnelt-aperture off-axis orientation has on the electron-momentum distribution, which modifies both the collection efficiency and the temporal-packet distribution relative to on-axis emission. Future needs are identified; we expect this and other developments in UEM electron-gun configuration to expand the range of material phenomena that can be directly imaged on scales commensurate with fundamental structural dynamics.

Advances in Nonreactive Polymer Compatibilizers for Commodity Polyolefin Blends.

Recycling mixed polyolefin plastics is a significant challenge due to the limitations in sorting and degraded mechanical properties of blends. Nonreactive compatibilization by adding a small amount of polymeric additive is a widespread approach to restoring the performance and value of recycled plastics. Over the past several decades, synthetic advances have enabled access to low-cost copolymers and precision architectures for deepening the understanding of compatibilization mechanisms in semicrystalline polyolefins. This review covers the design parameters of a polymeric compatibilizer, the testing of blends, the synthetic methods of producing economically viable additives, and surveys the literature of blends of compatibilized HDPE, LLDPE, LDPE, and iPP. From this, readers should gain a comprehension of the polymer mechanics, synthesis, and macromolecular engineering of processable polyolefin blends, along with the field's future directions.

Developments and Opportunities for 3D Bioprinted Organoids.

Organoids developed from pluripotent stem cells or adult stem cells are three-dimensional cell cultures possessing certain key characteristics of their organ counterparts, and they can mimic certain biological developmental processes of organs in vitro. Therefore, they have promising applications in drug screening, disease modeling, and regenerative repair of tissues and organs. However, the construction of organoids currently faces numerous challenges, such as breakthroughs in scale size, vascularization, better reproducibility, and precise architecture in time and space. Recently, the application of bioprinting has accelerated the process of organoid construction. In this review, we present current bioprinting techniques and the application of bioinks and summarize examples of successful organoid bioprinting. In the future, a multidisciplinary combination of developmental biology, disease pathology, cell biology, and materials science will aid in overcoming the obstacles pertaining to the bioprinting of organoids. The combination of bioprinting and organoids with a focus on structure and function can facilitate further development of real organs.

Dual Volume Image Fusion Technique for Anatomical Evaluation of Cavernous Sinus Dural Arteriovenous Fistula: Usefulness for Transvenous Target Segment Embolization

In this preliminary study, we investigated the value of fusion techniques by flat detector computed tomography based dual volume rotational angiography (DVRA) for the evaluation of the anatomical relationship of cavernous sinus dural arteriovenous fistula (CSDAVF) and assessed the possibility of transvenous target segment embolization. Twenty-six patients with CSDAVF supplied by multiple feeders underwent DVRA for each feeding large vessel separately. We assessed the anatomical relationship of feeders, fistula points, and venous drainage with three dual volume image fusion techniques. Transvenous embolization was targeted to the segment of fistulous point for preserving those not involved and reducing coil mass effect. Dual vessel multi-planar reconstruction fusion technique could show which segment of the cavernous sinus supplied by feeding arteries. In the dual vessel volume rendering fusion technique, the association between feeding arteries, fistula points, and draining veins of 2 different vessels could be accurately identified in 3 dimensions. In addition, we could visualize the exact anatomical relationship between the components of CSDAVF and skull anatomy with the single vessel fusion technique. Based on various fusion images, target segment embolization was successfully performed in 8 patients. In this group, we achieved complete or near complete occlusion without complications, including cranial nerve palsy. Detailed anatomical information including accurate fistula point, specific feeding arteries, and draining veins could be obtained with various dual volume image fusion techniques. In addition, the target segment embolization of CSDAVF could be possible with understanding of the precise CSDAVF architectures.

Development and Evaluation of 3D-Printed PLA/PHA/PHB/HA Composite Scaffolds for Enhanced Tissue-Engineering Applications

Recently, tissue engineering has been revolutionised by the development of 3D-printed scaffolds, which allow one to construct a precise architecture with tailored properties. In this study, three different composite materials were synthesised using a combination of polylactic acid (PLA), polyhydroxyalkanoates (PHA), poly(3-hydroxybutyrate) (PHB) and hydroxyapatite (HA) in varying weight percentages. Morphological properties were evaluated by scanning electron microscopy showing a uniform distribution of HA particles throughout the matrix, indicating good compatibility between the materials. Furthermore, the printed scaffolds were tested under pressure using a load cell to examine mechanical strength. Scanning electron microscopy (SEM) analysis showed favorable dispersion, biological compatibility together with enhanced bioactivity within the PHB/PHA/PLA/HA composite matrixes. Thus, this paper demonstrates the successful design and implementation of these composite structures for tissue-engineering applications and highlights the effective development of biocompatible scaffold designs with improved functionality.

Network-based time series modeling for COVID-19 incidence in the Republic of Ireland

Network-based time series models have experienced a surge in popularity over the past years due to their ability to model temporal and spatial dependencies, arising from the spread of infectious disease. The generalised network autoregressive (GNAR) model conceptualises time series on the vertices of a network; it has an autoregressive component for temporal dependence and a spatial autoregressive component for dependence between neighbouring vertices in the network. Consequently, the choice of underlying network is essential. This paper assesses the performance of GNAR models on different networks in predicting COVID-19 cases for the 26 counties in the Republic of Ireland, over two distinct pandemic phases (restricted and unrestricted), characterised by inter-county movement restrictions. Ten static networks are constructed, in which vertices represent counties, and edges are built upon neighbourhood relations, such as railway lines. We find that a GNAR model based on the fairly sparse Economic hub network explains the data best for the restricted pandemic phase while the fairly dense 21-nearest neighbour network performs best for the unrestricted phase. Across phases, GNAR models have higher predictive accuracy than standard ARIMA models which ignore the network structure. For county-specific predictions, in pandemic phases with more lenient or no COVID-19 regulation, the network effect is not quite as pronounced. The results indicate some robustness to the precise network architecture as long as the densities of the networks are similar. An analysis of the residuals justifies the model assumptions for the restricted phase but raises questions regarding their validity for the unrestricted phase. While generally performing better than ARIMA models which ignore network effects, there is scope for further development of the GNAR model to better model complex infectious diseases, including COVID-19.

Molecular-Scale Visualization of Steric Effects of Ligand Binding to Reconstructed Au(111) Surfaces.

Direct imaging of single molecules at nanostructured interfaces is a grand challenge with potential to enable new, precise material architectures and technologies. Of particular interest are the structural morphology and spectroscopic signatures of the adsorbed molecule, where modern probes are only now being developed with the necessary spatial and energetic resolution to provide detailed information at the molecule-surface interface. Here, we directly characterize the adsorption of individual m-terphenyl isocyanide ligands on a reconstructed Au(111) surface through scanning tunneling microscopy and inelastic electron tunneling spectroscopy. The site-dependent steric pressure of the various surface features alters the vibrational fingerprints of the m-terphenyl isocyanides, which are characterized with single-molecule precision through joint experimental and theoretical approaches. This study provides molecular-level insights into the steric-pressure-enabled surface binding selectivity as well as its effect on the chemical properties of individual surface-binding ligands.

Insight into the drying-mediated and thioether bond activated chiral inversion assembly of nano building blocks

Supramolecular materials are typically obtained from a solvent environment, while the assembled nano-structures always affected and unpredictably changed by irreversible evaporation of solvents, which brings great challenges for the precise controlling of assembled structures. Herein, a drying-mediated and thioether bond activated chiral inversion assembly behavior of organic/inorganic nano-building blocks polyhedral oligomeric silsesquioxane (POSS) was investigated. The POSS was modified by eight methylated terminal cysteine, while the existence of thioether bond could capture the hydrogen bonds belonging to amide groups during drying process, resulting in weaken of the inter-molecular hydrogen bonds and displacing the stacking of the nano-building blocks, which activates the forming of super-helical structures opposite to the original chirality. This research reveals the solvent-induced chiral assembly principle of the giant molecules and helpful for the construction of the precise architecture.

Digital precision in engineered ceramics: Tailoring toughness and flexibility through interlocking strategies

Precise material architectures and interfaces can render conventional ceramics tough, deformable and damage-resistant, offering a wide range of possibilities beyond those provided by conventional ones. This study explores the mechanical properties of topologically interlocked ceramic panels by systematically varying architectural parameters (i.e., interlocking angles and building block sizes) using a combination of experimental testing and finite element modeling based on COMSOL Multiphysics®. Three distinct designs were fabricated using digital laser manufacturing, categorized as designs with constant interlocking angles and tile sizes, constant interlocking angles and variable tile sizes, and variable interlocking angles and tile sizes and subjected them to out-of-plane quasi-static loads. The results show substantial enhancements in toughness (up to 110%) and strength (up to 120%) for ceramics with varying building block sizes, compared to those with constant block sizes. Additionally, these ceramics exhibit increased flexibility (up to 130%) compared to plain ceramics. Larger interlocking angles contribute to superior mechanical properties, fostering increased energy absorption and stability. The study also investigates post-failure behavior, revealing that increasing length ratios consistently augment the energy absorption. This research highlights the potential of these materials for flexible protection and the importance of controlling architectural parameters based on the interlocking angle and building block size to optimize performance while minimizing damage.

Early cretaceous multi-stage extension in the North Dabie complex in the eastern central China: insights from structural and geochronological data

A dominantly NW-SE directed extensional tectonics in the Early Cretaceous significantly reworked the Late Permian-Triassic orogenic framework of the Dabie orogenic belt. The North Dabie complex (NDC) is the principal domain recording this tectonic event. However, the precise structure-kinematic architectures, particularly those observed in the ductile regime, along with the respective time scales for different extensional stages, have not been adequately established. This significantly impedes our comprehensive understanding of the extensional style and deformation history in the North Dabie complex. To better address these issues, we conducted a systematic structural study and LA-ICP-MS zircon U-Pb dating of the pre-, syn-, and post-kinematic intrusions and syn-kinematically metamorphosed high-grade gneisses/migmatites of the NDC. Our results demonstrate that the extensional deformation in the NDC may initiate at ca. 144 Ma, which is characterized by a pervasive NW-SE oriented coaxial plastic flow in the ductile regime of the middle-lower crust. A large-scale detachment processing zone subsequently started activating at ca. 140 Ma at the upper-middle level of the middle crust, and concentratedly accommodated the extensional strain by top-to-NW ductile shearing. Locally, there was uprising of sub-magmatic flow in the atatexite-diatexite from the deeper lower crust taking place in the manner of top-to-outward shearing as early as ca. 137 Ma. This composite process of extension manifests vertical strain partitioning across the ductile middle-lower crusts and progressive strain localization during the lithospheric thinning. The NW-SE orientation dominated extensional tectonics was strongly driven by the westward subduction of the Paleo-Pacific oceanic plate during the Late Mesozoic.

Adaptisorption of Nonporous Polymer Crystals

AbstractAlthough our knowledge and understanding of adsorptions in natural and artificial systems has increased dramatically during the past century, adsorption associated with nonporous polymers remains something of a mystery, hampering applications. Here we demonstrate a model system for adaptisorption of nonporous polymers, wherein dative B−N bonds and host‐guest binding units act as the kinetic and thermodynamic components, respectively. The coupling of these two components enables nonporous polymer crystals to adsorb molecules from solution and undergo recrystallization as thermodynamically favored crystals. Adaptisorption of nonporous polymer crystals not only extends the types of adsorption in which the sorbate molecules are integrated in a precise and orderly manner in the sorbent systems, but also provides a facile and accurate approach to the construction of polymeric materials with precise architectures and integrated functions.

Adaptisorption of Nonporous Polymer Crystals.

Although our knowledge and understanding of adsorptions in natural and artificial systems has increased dramatically during the past century, adsorption associated with nonporous polymers remains something of a mystery, hampering applications. Here we demonstrate a model system for adaptisorption of nonporous polymers, wherein dative B-N bonds and host-guest binding units act as the kinetic and thermodynamic components, respectively. The coupling of these two components enables nonporous polymer crystals to adsorb molecules from solution and undergo recrystallization as thermodynamically favored crystals. Adaptisorption of nonporous polymer crystals not only extends the types of adsorption in which the sorbate molecules are integrated in a precise and orderly manner in the sorbent systems, but also provides a facile and accurate approach to the construction of polymeric materials with precise architectures and integrated functions.

Spacer Effects in Sulfo‐ and Sulfabetaine Polymers on Their Resistance against Proteins and Pathogenic Bacteria

AbstractThe resistance of zwitterionic polymer coatings against the adsorption of proteins and the attachment of pathogenic bacteria is influenced by the precise molecular architecture of the polymers. Two until now rarely studied molecular variables in this context are side chain spacer groups separating the zwitterionic moieties from the polymer backbone and spacer groups separating the cationic and anionic groups within the zwitterionic moiety. Therefore, a set of six poly(sulfobetaine)s and poly(sulfabetaine)s is prepared, in which these spacer groups are systematically varied, incorporating ethylene, propylene, and undecylene side chain spacers, as well as ethylene, propylene, and butylene inter‐charge spacers, and their effects on the antifouling behavior are explored. Hence, the corresponding zwitterionic methacrylates are copolymerized with a photo‐reactive methacrylate bearing a benzophenone moiety. All zwitterionic coatings reveal hydrophilic properties when immersed in water and those with relatively short spacers show effective suppression of non‐specific protein adsorption. Polysulfobetaines outperform the polysulfabetaine ones in terms of resistance against adhesion of bacteria. The overall best fouling protection is observed for the polysulfobetaine bearing a propylene side chain spacer, which coincides with their relatively highest water solubility. The results corroborate previous findings that even apparently minor molecular changes of polyzwitterions can strongly affect their antifouling performance.

Promoting sustainable safety: Integrating fall detection for person and wheelchair safety

Fall detection systems are crucial for ensuring the safety of the elderly, especially those who are wheelchair-bound. A potential remedy involves promptly detecting human falls in near real-time to facilitate rapid assistance. While various methods have been suggested for fall detectors, there remains a necessity to create precise and sturdy architectures, methodologies, and protocols for detecting falls, particularly among elderly individuals, especially those using wheelchairs. The objective is to design an affordable and dependable IoT-based system for detecting falls in wheelchair users, alerting nearby individuals for assistance and promote sustainable safety. The setup includes a MEMS Sensor, GSM module, and Arduino UNO microcontroller for detecting falls, with the goal of securing the well-being and promoting independent living for the elderly.