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This review is about the coordination and defect design of carbon-based single atom catalysts (SACs) from active sites and carbon skeletons to nanocarbon-based SACs, characterization, and application for energy catalysis.

Earthworms accumulate organic pollutants to form earthworm tissue-bound residues (EBRs); however, the composition and fate of EBRs in soil remain largely unknown. Here, we investigated the fate of tetrabromobisphenol A (TBBPA)-derived EBRs in soil for 250 days using a 14C-radioactive isotope tracer and the geophagous earthworm Metaphire guillelmi. The EBRs of TBBPA in soil were rapidly transformed into nonextractable residues (NERs), mainly in the form of sequestered and ester-linked residues. After 250 days of incubation, 4.9% of the initially applied EBRs were mineralized and 69.3% were released to extractable residues containing TBBPA and its transformation products (TPs, generated mainly via debromination, O-methylation, and skeletal cleavage). Soil microbial activity and autolytic enzymes of earthworms jointly contributed to the release process. In their full-life period, the earthworms overall retained 24.1% TBBPA and its TPs in soil and thus prolonged the persistence of these pollutants. Our study explored, for the first time, the composition and fate of organic pollutant-derived EBRs in soil and indicated that the decomposition of earthworms may release pollutants and cause potential environmental risks of concern, which should be included in both environmental risk assessment and soil remediation using earthworms.

Bolted joints play a more and more important role in the structure with lighter weight and heavier load. This paper aims to provide an overview of different experimental approaches for the dynamic behavior of structures in the presence of bolted joints, especially the energy dissipation or damping at frictional interfaces. The comprehension of energy dissipation mechanisms due to friction is provided first, while the key parameters and the measurement techniques, such as the excitation force, the preload of the bolt, or the pressure at the interfaces, are briefly introduced. Secondly, the round-robin systems aim to measure the hysteresis parameters of the frictional joints under tangential loads are reviewed, summarizing the basic theory and the strategies to apply the excitation force or acquire the response in different testing systems. Followed by parameter identification strategies for bolted structures, the test rigs with one or more simplified bolted joints are summarized to give an insight into the understanding of typical characteristics of bolted structures, which are affected by the presence of friction. More complex test rigs hosting real-like or actual engineering structures with bolted lap or flange joints are also introduced to show the identification process of the dynamic characteristics of bolted connections employed in specific applications. Based on the review paper, researchers can get the basic knowledge about the experimental systems of the bolted structures, especially several classical round robin systems, such as the Gaul resonator and widely used Brake-Reuß beam system. Readers can take advantage of this background for more creative and effective future studies, make more progress on the study of assembled structures and understand the influence of bolting frictional connections on the dynamic response better.

The incidence of hepatocellular carcinoma (HCC) has continued to increase annually worldwide, and HCC has become a common cause of cancer-related death. Despite great progress in understanding the molecular mechanisms underlying HCC development, the treatment of HCC remains a considerable challenge. Thus, the survival and prognosis of HCC patients remain extremely poor. In recent years, the role of ion channels in the pathogenesis of diseases has become a hot topic. In normal liver tissue, ion channels and transporters maintain water and electrolyte balance and acid‒base homeostasis. However, dysfunction of these ion channels and transporters can lead to the development and progression of HCC, and thus these ion channels and transporters are expected to become new therapeutic targets. In this review, ion channels and transporters associated with HCC are reviewed, and potential targets for new and effective therapies are proposed.

Molecular Sierpiński triangles (STs), a family of elegant and well-known fractals, can be prepared on surfaces with atomic precision. Up to date, several kinds of intermolecular interactions such as hydrogen bond, halogen bond, coordination, and even covalent bond have been employed to construct molecular STs on metal surfaces. Herein a series of defect-free molecular STs have been fabricated via electrostatic attraction between potassium cations and electronically polarized chlorine atoms in 4,4″-dichloro-1,1′:3′,1″-terphenyl (DCTP) molecules on Cu(111) and Ag(111). The electrostatic interaction is confirmed both experimentally by scanning tunneling microscopy and theoretically by density functional theory calculations. These findings illustrate that electrostatic interaction can serve as an efficient driving force to construct molecular fractals, which enriches our toolbox for the bottom-up fabrication of complex functional supramolecular nanostructures.

Fragrances, which are commonly used in food, textiles, consumer products, and medical supplies, are volatile compounds that require stabilization and controlled release due to their sensitivity to environmental conditions such as light, oxygen, temperature, and humidity. Encapsulation in various material matrices is a desired technique for these purposes, and there is a growing interest in using sustainable natural materials to reduce environmental impact. In this study, fragrance encapsulation in microspheres made from silk fibroin (SF) was investigated. Fragrance-loaded silk fibroin microspheres (Fr-SFMSs) were prepared by adding fragrance/surfactant emulsions to silk solutions, followed by mixing them with polyethylene glycol under ambient conditions. The study investigated eight different fragrances, where citral, beta-ionone, and eugenol showed higher binding affinities to silk than the other five fragrances, resulting in better microsphere formation with uniform sizes and higher fragrance loading (10–30%). Citral-SFMSs showed characteristic crystalline β-sheet structures of SF, high thermal stability (initial weight loss at 255 °C), long shelf life at 37 °C (>60 days), and sustained release (∼30% of citral remained after incubation at 60 °C for 24 h). When citral-SFMSs with different sizes were used to treat cotton fabrics, about 80% of the fragrance remained on the fabrics after one wash, and the duration of release from the treated fabrics was significantly longer than that of control samples treated with citral alone (no microspheres). This method of preparing Fr-SFMSs has potential applications in textile finishing, cosmetics, and the food industry.

One of the key issues for the use of organic radicals in high-performance molecular electronic, spintronic and thermoelectric devices is the retention, at room temperature, of their open-shell character when they are in contact with the metal electrodes of a junction. By means of first-principles quantum transport calculations, we have investigated the stability and the electronic transport properties of single-molecule junctions incorporating a Blatter radical (BR) with thiomethyl linker groups. Our calculations suggest that the BR can unequivocally retain its open-shell nature even when bound to gold electrodes through undercoordinated gold adatoms. Such a state cannot be destroyed by the surrounding solvent molecules and the applied bias. The calculated low-bias conductance values of junctions with BR, an oxidized BR derivative, and a closed-shell stilbene molecule are in quantitative agreement with the available experimental measurements. The small conductance of the BR can be associated with the localization of its π-type singly occupied and singly unoccupied molecular orbitals (SOMO and SUMO), leading to an asymmetrically weak electronic coupling to the two gold electrodes, even though these two orbitals lie very close to the Fermi energy. Furthermore, the nonmonotonic modulation of the junction conductance controlled by a charge gate can be used in experiments to further verify the presence of the unpaired electron. This proof may be realized in practice with an electrostatic solid-state or an electrochemical gate. Our findings deepen the current understanding of the radical–metal interfacial properties and facilitate the design of future radical-based multifunctional molecular devices.

Anomaly detection is a critical task for maintaining the performance of a cloud system. Using data-driven methods to address this issue is the mainstream in recent years. However, due to the lack of labeled data for training in practice, it is necessary to enable an anomaly detection model trained on contaminated data in an unsupervised way. Besides, with the increasing complexity of cloud systems, effectively organizing data collected from a wide range of components of a system and modeling spatiotemporal dependence among them become a challenge. In this article, we propose TopoMAD, a stochastic seq2seq model which can robustly model spatial and temporal dependence among contaminated data. We include system topological information to organize metrics from different components and apply sliding windows over metrics collected continuously to capture the temporal dependence. We extract spatial features with the help of graph neural networks and temporal features with long short-term memory networks. Moreover, we develop our model based on variational auto-encoder, enabling it to work well robustly even when trained on contaminated data. Our approach is validated on the run-time performance data collected from two representative cloud systems, namely, a big data batch processing system and a microservice-based transaction processing system. The experimental results show that TopoMAD outperforms some state-of-the-art methods on these two data sets.

Anisotropical engineering of surface-confined supramolecules provides a potential approach to precisely tweaking the properties and performance of low-dimensional molecular nanomaterials. Here, we report the construction of a surface-confined bicomponent supramolecular structure that features structural anisotropy by combined scanning tunneling microscopy and density functional theory studies. One-dimensional supramolecular ribbons formed by corannulene with either titanyl phthalocyanine or copper phthalocyanine exclusively extend along the equivalent ⟨11̅0⟩ directions on Ag(111). Such a supramolecular anisotropy is demonstrated as a result of the combined effects of molecule–substrate commensurability and intermolecular interaction relaxation, which leads to orientation-dependent energy cost for commensurate growth of the supramolecular ribbon on Ag(111). These findings provide insights into the mediation effect of the fine balance between the molecule–substrate and intermolecular interactions on the supramolecular structures, offering an efficient methodology for supramolecular anisotropical engineering.

Articular cartilage, which exhibits toughness and ultralow friction even under high squeezing pressures, plays an important role in the daily movement of joints. However, joint soft tissue lesions or injuries caused by diseases, trauma, or human functional decline are inevitable. Poly(vinyl alcohol) (PVA) hydrogels, which have a water content and compressive strength similar to those of many tissues and organs, have the potential to replace tough connective tissues, including cartilage. However, currently, PVA hydrogels are not suitable for complex dynamic environments and lack rebound resilience, especially under long-term or multicycle mechanical loads. Inspired by biological tissues that exhibit increased mechanical strength after swelling, we report a tough engineered hydrogel (TEHy) fabricated by swelling and freeze–thaw methods with a high compressive strength (31 MPa), high toughness (1.17 MJ m–3), a low friction coefficient (0.01), and a low energy loss factor (0.22). Notably, the TEHy remained remarkably resilient after 100 000 cycles of contact extrusion and remains intact after being compressed by an automobile with a weight of approximately 1600 kg. The TEHy also exhibited excellent water swelling resistance (volume and weight changes less than 5%). Moreover, skeletal muscle cells were able to readily attach and proliferate on the surface of TEHy-6, suggesting its outstanding biocompatibility. Overall, this swelling and freeze–thaw strategy solves the antifatigue and stability problems of PVA hydrogels under large static loads (>10 000 N) and provides an avenue to fabricate engineering hydrogels with strong antifatigue and antiswelling properties and ultralow friction for potential use as biomaterials in tissue engineering.

Objective: It has been demonstrated that IDO1, a target of immune checkpoint inhibition, functions as an oncogene in the majority of human malignancies. IDO1’s function in human pan-cancers hasn’t been thoroughly studied, though. Materials and methods: The Kaplan–Meier (K-M) and COX analyses were applied to the survival analysis. Furthermore, we used Spearman’s correlation analysis to examine the associations between IDO1and microsatellite instability (MSI), DNA methyltransferases (DNMTs), tumor mutational burden (TMB), the associated genes of mismatch repair (MMR), and immune checkpoint biomarkers. Moreover, immunohistochemical analysis and qRT-PCR were used to evaluate IDO1’s expression in pan-cancer cells. Results: The findings of this study reveal that IDO1has abnormal expression in a number of malignancies and is related to the prognosis for UVM, LGG, KIRP, GBM, LAML, OV, READ, MESO, SARC, SKCM, and HNSC. Furthermore, the aberrant IDO1expression was connected to the TMB, MSI, MMR, drug sensitivity, immune cells infiltrating, and tumor immune microenvironment across a variety of cancer types. The PCR results showed that in contrast to normal cells, IDO1 was found to be significantly highly expressed in breast cancer cells and hepatocellular carcinoma cells, and significantly lowly expressed in gastric cancer cells. Conclusion: The clinical treatment of IDO1 is now better supported by a theoretical basis and guidelines provided by our study.

Radiotherapy resistance poses a prevalent clinical challenge in non-small cell lung cancer (NSCLC), necessitating the development of ongoing treatment protocols following the emergence of radiotherapy resistance, as well as the identification of radiotherapy sensitization drugs. The objective of this study was to exclusively investigate therapeutic targets associated with radiotherapy resistance in NSCLC, thereby expanding the range of treatment alternatives available to patients grappling with radiotherapy resistance.

Fractals are found in nature and play important roles in biological functions. However, it is challenging to controllably prepare biomolecule fractals. In this study, a series of Sierpiński triangles with global organizational chirality is successfully constructed by the coassembly of l-tryptophan and 1,3-bi(4-pyridyl)benzene molecules on Ag(111). The chirality is switched when replacing l-tryptophan by d-tryptophan. The fractal structures are characterized by low-temperature scanning tunneling microscopy at the single-molecule level. Density functional theory calculations reveal that intermolecular hydrogen bonds stabilize the Sierpiński triangles.

Controlled construction of molecule-based nanostructures with specific spin-state ordering is significant for design of spintronic devices and magnetic materials. Here, we report on the fabrication of metallo-supramolecular chains featuring varied spin-state phases on different lattice planes of the Au substrate. The one-dimensional molecular structures are formed by coordination between deprotonated tetrahydroxybenzene and Ni on Au(100) and Au(110). By employing scanning tunneling microscopy/spectroscopy and density functional theory calculations, we identify Ni atoms in the coordination chains on Au(100) and Au(110) at a low-spin (LS, S= 0) and high-spin (HS, S= 1) state, respectively, giving rise to the LS phase on Au(100) and the HS phase on Au(110). We demonstrate that the selective stabilization of the different spin-state orderings on the Au substrates stems from the distinct ground states of the spin-state phase at varied Ni–Ni separations in the chains on the different Au surfaces. Such a lattice-plane-dependent variation in Ni–Ni distance is revealed as a result of the chain-substrate commensurability. These findings provide insights into the key role of the substrate effect in tuning the magnetic properties of surface-confined supramolecular systems.

Microalgae immobilized in hydrogels offer advantages over those cultured in suspension culture in terms of carbon fixation and oxygen emission. However, alginate as a commonly used hydrogel for microalgal immobilization encounters problems with mechanical strength and stability. To address this limitation, silk fibroin (silk) hydrogels prepared by ultrasonication were utilized to host microalgae when mixed with the presonicated protein solution prior to its gelation. The gelation time, stability, and light transmission of these silk gels were evaluated, and a silk concentration of 4% w/v and a gel thickness of 1 mm provided mechanical strength and stability during algal culture in comparison to alginate hydrogels. Furthermore, silk hydrogels with algal cell densities of 7.6 × 105and 7.8 × 107cells/mL had better stability than those with a lower cell density (3.2 × 103cells/mL), likely due to cell confinement and impact on proliferation. The silk hydrogels with microalgae at a high density generated 6.13 mg/L of oxygen continuously for 7 days. An oxygen-generating device was fabricated by coating the surface of a dialysis tube with a thin layer of the microalgae-embedded silk hydrogel, where the microalgal cells were nourished with culture medium prefilled in the dialysis tube. When suspended in a sealed flask filled with CO2gas, the system continuously produced oxygen (151 mL) for at least 60 days, with an oxygen production efficiency 6 times that of microalgal suspension culture controls. This microalgae embedding and cultivation technique could have potential utility in air purification, tissue repair, and other applications due to the efficient and sustained generation of oxygen.

The crystallographic preferred orientation (CPO) of olivine, specifically the type‐B characterized by c‐axes aligned parallel to lineation and b‐axes concentrated perpendicular to foliation, is essential for explaining the trench‐parallel seismic anisotropy in the forearc regions of subduction zones. However, its origin remains a subject of ambiguity and controversy. In this study, we present experimental findings on the formation of a type‐B olivine CPO through the dehydration of foliated serpentinite under a compressive stress at a pressure of 300 MPa and temperature of 700–750°C. Our results reveal a progressive evolution of olivine CPO, transitioning from a type‐C fabric to a type‐B fabric, with increasing grain size and dehydration level. The type‐B CPO observed in coarse‐grained olivine within fully dehydrated samples primarily arises from mechanisms involving anisotropic growth, grain rotation, and oriented coalescence of newly formed, small olivine grains following the decomposition of antigorite under a compressive stress. This study provides the first experimental evidence for a novel, low‐temperature dynamic dehydration mechanism, in contrast to the mechanism of high‐temperature plastic flow, for explaining the development of type‐B olivine CPO in forearc regions. Hence, it contributes significantly to our understanding of the formation of olivine CPO with implications for seismic anisotropy in subduction zone forearcs. This study focuses on understanding why rocks in the forearc regions near subduction zones, where one tectonic plate slides beneath another, have a specific type of olivine arrangement known as type‐B olivine fabric. This arrangement is responsible for explaining why seismic velocities have a certain pattern in those areas. However, there has been disagreement about how this arrangement of olivine comes about. To investigate this, we conducted experiments where we subjected rocks rich in antigorite to high temperatures, causing them to transform into olivine. During these experiments, we observed changes in the size and shape of olivine grains, and their arrangement shifted from type‐C to type‐B as we adjusted the temperature and duration of the experiments. We found a relationship between the shape of olivine grains and how they were arranged. This change in arrangement can be explained by factors like the grains growing in different directions, rotating, and coming together in a specific way. Our discovery suggests that this particular olivine arrangement can occur during the transformation from antigorite to olivine at relatively low temperatures. This arrangement plays a more significant role for the trench‐parallel seismic anisotropy in the subduction forearc regions than we previously understood. Dynamic dehydration of antigorite triggers the evolution of olivine crystallographic preferred orientation (CPO) from type‐C to type‐BTransitional type‐C olivine CPO is induced by topotactic and anisotropic growth of olivine during antigorite dehydrationType‐B olivine CPO is the final form of antigorite dehydration generated by anisotropic growth, grain rotation, and oriented coalescence Dynamic dehydration of antigorite triggers the evolution of olivine crystallographic preferred orientation (CPO) from type‐C to type‐B Transitional type‐C olivine CPO is induced by topotactic and anisotropic growth of olivine during antigorite dehydration Type‐B olivine CPO is the final form of antigorite dehydration generated by anisotropic growth, grain rotation, and oriented coalescence

Surface with well-defined components and structures possesses unique electronic, magnetic, optical and chemical properties. As a result, surface chemistry research plays a crucial role in various fields such as catalysis, energy, materials, quantum, and microelectronics. Surface science mainly investigates the correspondence between surface property and functionality. Scanning probe microscopy (SPM) techniques are important tools to characterize surface properties because of the capability of atomic-scale imaging, spectroscopy and manipulation at the single-atom level. In this review, we summarize recent advances in surface electronic, magnetic and optical properties characterized mainly by SPM-based methods. We focus on elucidating the π-magnetism in graphene-based nanostructures, construction of spin qubits on surfaces, topology properties of surface organic structures, STM-based light emission, tip-enhanced Raman spectroscopy and integration of machine learning in SPM studies.

The coordination abilities of different functional groups play fundamental roles in metal–organic frameworks. The coordination of indole-4-carboxylic acid with Fe on surfaces was investigated by scanning tunneling microscopy and density functional theory. The carboxyl group reacted with Fe atoms to form tetramers in a deprotonation process on Au(111) at room temperature. The deprotonation of pyrrolyl groups occurred at around 350 K, forming coordinated tetramer chains and rotiform structures. The arrangement of tetrameric clusters and coordination chains on Au(100) was influenced by surface reconstitution. A two-dimensional coordination network was obtained on Ag(111) without the influence of surface reconstitution.

Electrons not only serve as a “reactant” in redox reactions but also play a role in “catalyzing” some chemical processes. Despite the significance and ubiquitousness of electron-induced chemistry, many related scientific issues still await further exploration, among which is the impact of molecular assembly. In this work, microscopic insights into the vital role of molecular assembly in tweaking the electron-induced surface chemistry are unfolded by combined scanning tunneling microscopy and density functional theory studies. It is shown that the selective dissociation of a C–Cl bond in 4,4″-dichloro-1,1′:3′,1′′-terphenyl (DCTP) on Cu(111) can be efficiently triggered by an electron injection via the STM tip into the unoccupied molecular orbital. The DCTP molecules are embedded in different assembly structures, including its self-assembly and coassemblies with Br adatoms. The energy threshold for the C–Cl bond cleavage increases as more Br adatoms stay close to the molecule, indicative of the sensitive response of the electron-induced surface reactivity of the C–Cl bond to the subtle change in the molecular assembly. Such a phenomenon is rationalized by the energy shift of the involved unoccupied molecular orbital of DCTP that is embedded in different assemblies. These findings shed new light on the tuning effect of molecular assembly on electron-induced reactions and introduce an efficient approach to precisely steer surface chemistry.

The retention of the open-shell character of radicals when they are contacted to metallic electrodes in a junction is the primary prerequisite for their applications in high-performance molecular electronic, spintronic, and thermoelectric devices. Based on first-principles quantum transport calculations, we have investigated the spin state and the electronic transport properties of a series of single-molecule junctions incorporating a Blatter radical (BR) with thiol linkers and having diverse Au–S interfacial configurations. Our calculations suggest that the presence of Au–S bonding with a larger coordination number is conducive to maintaining the open-shell nature of the BR within a junction. If one treats the BR and the bonded Au adatoms as the central molecule, it is the energy of the singly occupied molecular orbital (SOMO) of the BR in such a unit (the so-called BR SOMO) that mainly determines the spin state of the molecule in the junction. Notably, the coupling strength between the BR SOMO and the electronic continuum states of the gold electrodes appears to play only a secondary role. These two factors together determine the electron population on the BR SOMO and thus the spin state of the BR within a junction. Our findings fill in gaps in understanding the influence of the metal–radical interfacial configurations on the open-shell character of a radical when bound in a junction. This knowledge facilitates the implementation of future radical-based multifunctional molecular devices.

The ability to control the nature of charge carriers in single-molecule junctions is of paramount importance to the design of molecular scale CMOS logic circuits. One major limitation is that the present methods for tuning the polarity of the charge carriers in molecular junctions always rely on chemical modifications of certain moieties of the central molecule. Here we investigate this issue by computing the electronic transport properties of graphene–porphine–graphene (GPG) molecular junctions with the nonequilibrium Green’s function formalism combined with density functional theory. Our calculations show that the dominant charge carriers in these GPG junctions can be tuned from holes to electrons by simply varying the number of C–C covalent bonds formed at the porphine-graphene interfaces. When porphine is doubly fused to graphene, it exhibits p-type transport behavior; in contrast, the triply fused one displays n-type behavior. The cause of this is that distinct linkage motifs lead to a rearrangement of the molecular levels participating in charge transport. It is the first time that such effect is shown without using a chemical modification of the porphine. In addition, hydrogen tautomerization reaction in porphine induces a dramatic conductance switch for the doubly fused GPG junctions, suggesting promising applications of this system as two-level molecular switch or memory unit with binary digits.

Surface chemistry focuses on the investigation of the adsorption, migration, assembly, activation, reaction, and desorption of atoms and molecules at surfaces. Surface chemistry plays the pivotal roles in both fundamental science and applied technology. This review will summarize the recent progresses on surface assembly, synthesis and catalysis investigated mainly by scanning tunneling microscopy and atomic force microscopy. Surface assemblies of water and small biomolecules, construction of Sierpiński triangles and surface chirality are summarized. On-surface synthesis of conjugated carbo- and heterocycles and other kinds of carbon nanostructures are surveyed. Surface model catalysis, including single-atom catalysis and electrochemical catalysis, are discussed at the single-atom level.

Various Sierpiński triangles (STs) have been constructed on surfaces, but minimal research efforts focus on their properties. In this work, three different types of STs are prepared with iron atoms as metal centers, and 4,4″-dicyano-1,1′:3′,1″-terphenyl, 1,3-bis(4-pyridyl)-benzene, and 4,4″-dihydroxy-1,1′:3′,1″-terphenyl as organic ligands, respectively. The spin excitation of magnetic Fe atoms in STs is investigated by low-temperature scanning tunneling microscopy. In the STs consisting of Fe atoms and 4,4″-dihydroxy-1,1′:3′,1″-terphenyl molecules, spin excitation of Fe atoms is observed in the spectra measured by scanning tunneling spectroscopy. For the other two ligands, the related spin excitation has not been found in spectra. Density functional theory calculations explain the excitation mechanism of Fe atoms in STs. The results pave the way for tuning spin excitation of magnetic atoms using ligand molecules with various functional groups.

Geometries of molecule-molecule interfaces strongly influence the current passing from one molecule to another. The contact conductance of molecule-molecule junctions which consist of fullerene and tin phthalocyanine molecules is investigated with a low-temperature scanning tunneling microscope. Two types of molecules are deposited onto Cu(111). Fullerene molecules are transferred to tips through controlled contact of STM tips on molecules. The molecule-molecule junctions are formed by approaching fullerene-terminated tips to tin phthalocyanine molecules on Cu(111). Our experimental method can be extended to study the intermolecular charge transport of a range of molecular junctions.

The present study described a new method with one step to fabricate silk fibroin nano- and microspheres, with the size of spheres and crystalline structure being controllable during processing. Polyethylene glycol, a type of synthetic polymer that is widely used in the pharmaceutical industry as a formulation excipient, was utilized to induce silk fibroin to self-assemble into nano- and microspheres. The addition of a certain amount of salt in the blending solution with subsequent titration into ethanol could improve the size dispersion, yield, and crystalline β-sheet structure (silk II) compared to those prepared without salt addition during preparation. Silk microspheres prepared in the presence of salts were less porous and more homogeneous in size than those prepared in the absence of salts.

Fractals are of fundamental importance in science and technology. Theoretical simulations indicate that Sierpiński triangles (STs) possess specific optical and electronic properties. To study their properties and uncover their potential applications, it is necessary to pack STs into large-scale two-dimensional crystalline structures. Here, a series of ordered structures consisting of ST units are successfully constructed on gold surfaces through coordination between 1,3-bis(4-pyridyl) benzene molecules and Fe atoms. Crystals of STs are characterized by scanning tunneling microscopy. K-map analysis explains the structural formation mechanism, which is further verified by density functional theory calculations. The molecular free diffusion and nice structure matching between STs and gold surfaces play important roles in the formation of crystals of STs.

A potential risk from human uptake of microplastics is the release of plastics-associated xenobiotics, but the key physicochemical properties of microplastics controlling this process are elusive. Here, we show that the gastrointestinal bioaccessibility, assessed using an in vitro digestive model, of two model xenobiotics (pyrene, at 391–624 mg/kg, and 4-nonylphenol, at 3054–8117 mg/kg) bound to 18 microplastics (including pristine polystyrene, polyvinyl chloride, polyethylene terephthalate, polypropylene, thermoplastic polyurethane, and polyethylene, and two artificially aged samples of each polymer) covered wide ranges: 16.1–77.4% and 26.4–83.8%, respectively. Sorption/desorption experiments conducted in simulated gastric fluid indicated that structural rigidity of polymers was an important factor controlling bioaccessibility of the nonpolar, nonionic pyrene, likely by inducing physical entrapment of pyrene in porous domains, whereas polarity of microplastics controlled bioaccessibility of 4-nonylphenol, by regulating polar interactions. The changes of bioaccessibility induced by microplastics aging corroborated the important roles of polymeric structures and surface polarity in dictating sorption affinity and degree of desorption hysteresis, and consequently, gastrointestinal bioaccessibility. Variance-based global sensitivity analysis using a deep learning neural network approach further revealed that micropore volume was the most important microplastics property controlling bioaccessibility of pyrene, whereas the O/C ratio played a key role in dictating the bioaccessibility of 4-nonylphenol in the gastric tract.