Search

We report the facile construction of a molecular 818knot and a molecular Borromean rings assembly through self-assembly directed by Cp*Rh corner units. Two curved ligands of similar size and shape were used in this study. The slight steric differences between the two ligands induce the formation of distinctly different topologies of the assembled products. The structures were confirmed by single-crystal X-ray analysis and nuclear magnetic resonance spectroscopy.

Realizing topological transformation through supramolecular fusion is particularly challenging, as the self-assembly of disparate components often results in the orthogonal assembly of building blocks into distinct structures rather than the formation of a heteroleptic architecture. This study introduces a topological transformation, transitioning from a figure-eight knot (41knot) to a Solomon link (412link) through a supramolecular fusion process. By employing two structurally similar amino acid ligands (L1and L3) of varying lengths as bridge ligands, we obtained figure-eight knot 1and a molecular tweezer-like compound 3when individually complexed with binuclear Cp*Rh acceptor B1. Our results revealed that subtle modifications to bridge ligands can lead to dramatic changes in their structures and recognition properties. Moreover, we successfully achieved the targeted formation of a heteroleptic Solomon link 4by blending figure-eight knot 1and compound 3in a 1:1 ratio without the need for templates. This procedure effortlessly converted the 41knot into a 412link, thus marking a significant advancement in the topological transformation. This work not only marks the construction of the first heteroleptic Solomon link comprising two distinct metallamacrocycles but also demonstrates a process of supramolecular fusion-based topological transformation involving three distinct topological structures.

Graphical abstract: An oligo(N,O-donor) fluorescent probe SASwith high selectivity for Al3+in DMF: H2O (9:1, V/V) Tris–HCl solution was designed and synthesized. The addition of Al3+excites the yellow fluorescence of SAS, which produces a strong fluorescence emission peak at 539 nm. The probe SASwas highly selective and sensitive for the detection of Al3+with the lowest detection limit of 6.61 × 10–8. Fluorescence titration and DFT calculations verified the recognition mechanism, and the chelating fluorescence generated by the coordination of metal ions Al3+enhanced the CHEF effect.

The properties and elevated temperature wear mechanism of pure copper and in situ TiC/Cu matrix composites fabricated via combustion synthesis assisted with hot press were investigated. Brinell hardness, compression properties and electrical conductivity were studied. It was found that of the Brinell hardness, yield strength and compressive strength of the composites is higher than sintered pure copper, however, the electrical conductivity and fracture strain of the composites are lower. Dry sliding friction and wear tests showed that the worn surface transformed from furrow to spalling pit and the wear rate increases with the increasing temperature and applied load, the wear failure changes gradually from surface plastic deformation, plough wear and oxidation wear to abrasive wear and fatigue spalling wear.

The quest for more efficient, user-friendly, and less wasteful topological transformations remains a significant challenge in the realm of postassembly modifications. In this article, high yields of two molecular trefoil knots (Rh-1, Ir-1) were obtained using ligand 3,6-bis(3-(pyridin-4-yl)phenyl)-1,2,4,5-tetrazine (L1) with reactive tetrazine units and binuclear half-sandwich organometallic units [Cp*2M2(μ-TPPHZ)(OTf)2](OTf)2(Rh-B, M = RhIII; Ir-B, M = IrIII). 2,5-Norbornadiene was used as an inducer of the Diels–Alder click reaction to modulate rapidly and efficiently the transformation of Trefoil knots to Solomon links. However, the key to achieving this topological structural change is the subtle increase in site steric of the pyridazine fragments (L2), which allows the molecular structures to spread and bend in three-dimensional space, as confirmed by single-crystal X-ray diffraction, ESI-TOF/MS, elementary analysis and detailed solution-state NMR techniques.

C18H16BrN3O2S, triclinic, P1̄(no. 2), a= 11.5820(4) Å, b= 12.0492(4) Å, c= 14.3048(5) Å, α= 73.673(3)°, β= 88.190(3)°, γ= 72.686(3)°, V= 1826.02(12) Å3, Z= 4, Rgt(F) = 0.0580, wRref(F2) = 0.1565, T = 296(2) K.

Four new [FeFe]-hydrogenase-mimic-containing CPs and a supramolecule, {(CO)6[Fe2S2–Ag](2-cpmt)2(SbF6)·0.5(CH2Cl2)}n(1), {(CO)6[Fe2S2–Ag](2-cpmt)2(ClO4)}n(2), {(CO)6[Fe2S2](2-cpmt)2Ag(p-xylene)(CF3SO3)}n(3), and {(CO)5(PPh3)[Fe2S2–Ag](2-cpmt)2(ClO4)·1.5(toluene)}n(4), were obtained from two new chelating ligands [FeFe](2-cpmt)2(CO)6(L1) and [FeFe](2-cpmt)2(CO)5(PPh3) (L2) by direct synthesis. All new compounds are characterized by single-crystal X-ray diffraction, FTIR, solid-state UV–vis spectra, and CV. It was noteworthy that L1and L2serve as multidentate ligands with two terminal −CN groups, the μ2-S atoms, and the CC≡Oas coordination sites, and the coordination modes between Ag+and multidentate chelating ligands are completely different from each other in four complexes. The results of photochemical H2generation experiments indicated that L2has greatly improved catalytic performance over L1due to the PPh3substituent. The amount of hydrogen produced from four Ag complexes 1–4is different due to the coordination environment difference around catalytic active sites. This work enriched the coordination chemistry of [FeFe]-hydrogenase mimics and improved the H2production performance of heterogeneous [FeFe]-hydrogenase catalysts.

Cracks have consistently been a significant challenge limiting the development of additive manufactured nickel-based superalloys. It is essential to investigate the location of cracks and their forming mechanism. This study extensively examines the impact of solidification process, microstructural evolution, and stress concentration on crack initiation during direct energy deposition (DED). The results emphasize that the crack formation is significantly related to large-angle grain boundaries, rapid cooling rates. Cracks caused by large-angle grain boundaries and a fast-cooling rate predominantly appear near the edge of the deposited samples. Liquation cracks are more likely to form near the top of the deposited sample, due to the presence of γ/γ′ eutectics. The secondary dendritic arm and the carbides in the interdendritic regions can obstruct liquid flow during the final stage of solidification, which results in the formation of solidification cracks and voids. This work paves the way to avoid cracks in nickel-based superalloys fabricated by DED, thereby enhancing the performance of superalloys.

Using the strategy of ligand fine-tuning by steric hindrance, we successfully obtained Solomon links (412) and figure-eight knots (41) with half-sandwich organometallic unit and amino-acid embedded ligands. The two curved bidentate ligands exhibit subtle differences, whereas they result in totally distinct entanglement modes. An alcoholysis reaction with the ligands leads to the formation of a molecular tweezer. Notably, unsymmetrical ligands were utilized in the self-assembly process to explore the formation of directional molecules, and the reactions exhibited selectivity due to comprehensive πinteractions and multiple hydrogen bonds. The topologies and behavior of the above structures were confirmed through single-crystal X-ray diffraction, nuclear magnetic resonance techniques and mass spectrometry.

The utilization of carboranes in supramolecular chemistry has attracted considerable attention. The unique spatial configuration and weak interaction forces of carboranes can help to explore the properties of supramolecular complexes, particularly via host–guest chemistry. Additionally, certain difficulties encountered in carborane development─such as controlled B–H bond activation─can be overcome by judiciously selecting metal centers and their adjacent ligands. However, few studies are being conducted in this nascent research area. With advances in this field, novel carborane-based supramolecular complexes will likely be prepared, structurally characterized, and intrinsically investigated. To expedite these efforts, we present major findings from recent studies, including π–π interactions, host–guest associations, and steric effects, which have been leveraged to implement a regioselective process for activating B(2,9)–, B(2,8)–, and B(2,7)–H bonds of para-carboranes and B(4,7)–H bonds of ortho-carboranes. Future studies should clarify the unique weak interactions of carboranes and their potential for enhancing the utility of supramolecular complexes. Although carboranes exhibit several unique weak interactions (such as dihydrogen-bond [Bδ+–Hδ−···Hδ+–Cδ−], Bδ+–Hδ−···M+, and Bδ+–Hδ−···π interactions), the manner in which they can be utilized remains unclear. Supramolecular complexes, particularly those based on host–guest chemistry, can be utilized as a platform for demonstrating potential applications of these weak interactions. Owing to the importance of alkane separation, applications related to the recognition and separation of alkane isomers via dihydrogen-bond interactions are primarily summarized. Advances in the research of unique weak interactions in carboranes will certainly lead to more possibilities for supramolecular chemistry.

To improve the corrosion resistance of coalbed methane drilling equipment, an AlCoCrFeNiCu high entropy alloy coating was prepared on the AISI 4135 (35CrMo) steel substrate by high velocity oxygen fuel (HVOF) technology, and the coating was subjected to vacuum heat treatment (VHT) at different temperatures (500, 700, 900 and 1100 °C). The corrosion test of the substrate and the coatings after VHT in coalbed methane drilling fluid was carried out. The results show that the HVOF sprayed AlCoCrFeNiCu high entropy alloy (HEA) coating has a good bonding with the substrate, and the porosity of the coating is about 2.4%. There is partial segregation in the coating, and the coating mainly consists of body-centered cubic phase. The coating has good thermal stability, and the phase structure and microstructure of the coatings have changed after VHT at different temperatures. Compared with the substrate, the as-sprayed coating has better uniform corrosion resistance, and the corrosion resistance of the coating after VHT is further improved. After VHT at 500 °C, the HVOF-sprayed AlCoCrFeNiCu HEA coating has the best corrosion resistance.

• A novel Cu 2.3 Al 1.3 Ni 1.7 SnCr 0.3 multi-principal element alloy (MPEA) and a multi-step ultrasonic assisted (UA) laser remelting technology were proposed. • An unusual ultrafine lamellar eutectic structure exists in Cu 2.3 Al 1.3 Ni 1.7 SnCr 0.3 UA-MPEA coating. • The effect of the FCC and eutectic phases on the corrosion behavior of the Cu 2.3 Al 1.3 Ni 1.7 SnCr 0.3 MPEA coatings was studied. • The passive films formed on the Cu 2.3 Al 1.3 Ni 1.7 SnCr 0.3 MPEA coatings exhibits duplex semiconductor behavior in NaCl solution. The evaporation and dilution of substrate seriously limit the performance of laser cladding coatings on magnesium alloys. In order to overcome the above shortcomings, a multi-step ultrasonic assisted laser remelting technology was proposed to improve the performance of the coating. In this work, a novel Cu 2.3 Al 1.3 Ni 1.7 SnCr 0.3 multi-principal element alloy coating (MPEAC) was prepared on the surface of magnesium alloy. Characterization techniques such as transmission electron microscopy (TEM), electron back scatter diffraction (EBSD) and scanning electron microscopy (SEM) were employed to characterize the microstructure and phase composition of the coatings. And the phase structure and morphology at the interface between the coating and the substrate were also studied via focus ion beam (FIB) and TEM method. In addition, the corrosion and wear resistance ability of the coatings were monitored by potentiodynamic polarization (PDP), and electrochemical impedance spectroscopy (EIS), hardness and friction tests. The results show that Cu 2.3 Al 1.3 Ni 1.7 SnCr 0.3 MPEAC with ultrasonic assisted is composed of FCC phase and eutectic phases (Cu 10 Sn 3 and Cu 2 Ni 3 Sn 3). Due to the forced convection generated by ultrasonic waves, some Cu and Ni phases are precipitated around Cu 2 Ni 3 Sn 3 phases, which is beneficial to enhance the corrosion resistance. Because of the grain refinement effect caused by ultrasonic, the wear resistance of the coating is also improved. Furthermore, ultrasonic vibration can effectively weaken and eliminate the texture density of the Cu 2.3 Al 1.3 Ni 1.7 SnCr 0.3 MPEAC fabricated by laser cladding. [ABSTRACT FROM AUTHOR]

The three-phase contact line best reflects the sliding ability of droplets on solid surfaces. Most studies on the sliding angle (SA) of superhydrophobic surfaces are limited to regularly arranged microtextured surfaces, lacking definite models and effective methods for a complex surface of a random texture. In this study, random pits with an area ratio of 19% were generated on 1 mm × 1 mm subregions, and the subregions formed arrays on a sample surface of 10 mm × 10 mm to obtain a randomly distributed microtexture surface with no pit overlaps. Although the contact angle (CA) of randomly pitted texture was the same, the SA was different. The SA of surfaces was affected by the pit location. The location of random pits increased the complexity of the three-phase contact line movement. The continuity of the three-phase contact angle (T) can reveal the rolling mechanism of the random pit texture and predict the SA, but the relationship between the Tand SA is a relatively poor linear relation (R2= 74%), and the SA of the random pit texture can only be roughly estimated. The quantized pit coordinates and SA were used as the input and output labels for the PNN model, respectively, and the accuracy of the model convergence was 90.2%.

Developing novel assembly methods for supramolecular compounds has long been a research challenge. Herein, we describe how to integrate the B–C coupling reaction and “cage walking” process into coordination self-assembly to construct supramolecular cages. In this strategy, dipyridine linkers containing alkynes react with the metallized carborane backbone through B–C coupling and then “cage walking” resulting in metallacages. However, dipyridine linkers without alkynyl groups can form only metallacycles. We can regulate the size of metallacages based on the length of the alkynyl bipyridine linkers. When tridentate-pyridine linkers participate in this reaction, a new type of ravel is formed. The metallization of carboranes, the B–C coupling reaction, and especially the “cage walking” process of carborane cages play a vital role in this reaction. This work provides a promising principle for the synthesis of metallacages and opens up a novel opportunity in the supramolecular field.

The microstructure and tensile properties of a new Ni-based superalloy specially designed for additive manufacture (AM) were investigated under different laser power (LP) conditions. The results measured by X-ray diffraction analysis and scanning electron microscopy show that no cracks are observed in as-deposited alloy, which has typical crystallography orientation and non-equilibrium solidification dendrite/cellular morphology. The elements such as Nb, Si and Ti are enriched in the interdendritic regions, while Al, Cr and Co segregate in the dendritic cores. When the LP is low, the cellular crystals of the alloy are arranged orderly, the primary dendrite arm space (PDAS) is small, the porosity is large, the strength is high and the elongation is low. With the increase of LP, the PDAS increases, the porosity decreases, the strength decreases and the elongation increases. When the LP is elevated further, Marangoni convection effect is enhanced and shows unique impacts, that is, the disordered arrangement of cellular crystals occurs. Then, the PDAS decreases, the porosity increases, the strength increases and the elongation decreases. The smaller PDAS favors the reduction for elements segregation, as well as microstructure refinement and strength improvement. The fitting formula between PDAS and yield strength (YS) was proposed, and the concentric ring patterns inside microstructure were rationalized.

The variation law of inclusions type and size in the vacuum induction melting process and ingot of Ni-based superalloy containing 70% return material was studied by industrial test sampling, and the mechanism of inclusions formation was analyzed with thermodynamic calculations. The results show that there are mainly two types of composite inclusions in the vacuum induction melting of Ni-based superalloys, which are nitride- and oxide-based composite inclusions, like Al2O3–SiO2–Cr2O3, TiN–(Mo, Nb)C, etc. The type and proportion of inclusions from the center to the edge of the vacuum induction ingot did not change significantly. The number density of inclusions from the center to the edge of the ingot varied less, and the size of inclusions became smaller from the center to the edge. In addition, thermodynamic calculations show that oxides (M2O3) are present in the liquid phase and mainly contain Al, Ti, Cr, Fe and O elements. The nitride consists mainly of Ti and N and contains small amounts of Cr, C, Nb, and Mo elements. This is consistent with the results of industrial tests. As the temperature decreases, the precipitation phases such as M2O3, MN, γ, MC, δ, γ′and μ phases are gradually precipitated, where oxides and nitrides are present in the liquid phase. The contents of O and N elements are the main influencing factors for the inclusions content and precipitation temperature; when the nitrogen content is reduced to below 0.0015%, it can make MN precipitate below the liquid-phase line.

Ceramic cores are the key intermediate components of hollow blades for aero-engine. Conventional processes, such as hot-press molding and gel film casting, face difficulties in fabricating complex-structured ceramic cores due to the complexity of moulds and long process cycles. Stereolithography 3D printing provides a new idea for the fabrication of complex-structured ceramic cores. The effect of sintering temperature on open porosity, bulk density, weight loss rate, shrinkage rate, flexural strength and microstructure of the Al2O3-based ceramic core doped with 10vol.% polysilazane (PSZ) was studied. The sintering mechanism of PSZ-reinforced ceramic cores was analyzed. Results show that the optimum sintering temperature of PSZ-reinforced ceramic cores is 1,450 °C. At this temperature, the open porosity of the ceramic core is 36.60%, bulk density is 2.33 g·cm−3, weight loss rate is 22.11%, shrinkage rate along the X, Y, Zdirections is 5.72%, 5.01%, 9.61%, respectively; the flexural strength is 28.794 MPa at 25 °C and 13.649 MPa at 1,500 °C. Properties of 3D printing PSZ-reinforced ceramic cores can meet the casting requirement of superalloy hollow blades, which is expected to promote the industrial application of 3D printing complex structure ceramic cores.

The specific recognition and separation of alkanes with similar molecular structures and close boiling points face significant scientific challenges and industrial demands. Here, rectangular carborane-based metallacycles were designed to selectively encapsulate n-pentane from n-pentane, iso-pentane, and cyclo-pentane mixtures in a simple-to-operate and more energy-efficient way. Metallacycle 1, bearing 1,2-di(4-pyridyl) ethylene, can selectively separate n-pentane from these three-component mixtures with a purity of 97%. The selectivity is ascribed to the capture of the preferred guest with matching size, C–H···π interactions, and potential B–Hδ−···Hδ+–C interactions. Besides, the removal of n-pentane gives rise to original guest-free carborane-based metallacycles, which can be recycled without losing performance. Considering the variety of substituted carborane derivatives, metal ions, and organic linkers, these new carborane-based supramolecular coordination complexes (SCCs) may be broadly applicable to other challenging recognition and separation systems with good performance.

In aluminum alloys, the most often utilized cast Al–Si alloy system, the microstructure often needs to be improved by modification and inoculation treatment. This study comprehensively examines the impact of nanocrystals produced by Fe–B–Si amorphous alloys on the solidification behavior and microstructure of hypoeutectic Al–Si7alloy and hypereutectic Al–Si17alloy. The nucleation temperature of α-Al is increased and the nucleation of α-Al is easier as well as crystallization platform becomes shorter. For primary Si, the nucleation temperature is decreased and the nucleation is inhibited. The eutectic transformation is promoted and the reaction time is shortened. For α-Al, in situ nano-Fe2B can act as its heterogeneous nucleation sites and promote its nucleation. Meanwhile, the growth of α-Al dendrites is constrained by nearby grains and nanocrystals that do not participate in nucleation, therefore refining the dendrites. Furthermore, nano-Fe2B promotes the eutectic transformation and refines the eutectic microstructure. At the same time, the microstructure of the eutectic groups is refined and the distribution is more dispersed due to the confinement of finer adjacent grains and the hindrance of nanocrystals that do not participate in nucleation.

Introduction and objectives: In diseases characterized by fibrosis, hepatic stellate cells (HSCs) are mesenchymal cells that play an important role in liver fibrosis. circRNAs are involved in regulating hydatid exocyst formation through miRNA sponge adsorption. The mechanisms of hepatic cystic hydatid outer cyst formation, HSC, and liver fibrosis are unclear. Materials and methods: Based on our sequencing data, we validated the mechanism by which circRNA-049637 regulated hepatic cystic hydatid growth and promoted outer fibrocystic wall formation. Results: Our results revealed that circRNA_049637 silencing promoted the proliferation of LX-2 human HSCs, affected the cell cycle, and increased the mRNA and protein expression levels of liver fibrosis-related indicators such as α-SMA, COL1A1, COL3A1, and TGFβRII. Conclusions: CircRNA_049637 may induce the formation of hepatic hydatid cysts by promoting hepatic fibrosis via HSC activation.

Separation of light hydrocarbons (C1–C9) represents one of the “seven chemical separations to change the world”. Boron clusters can potentially play an important role in chemical separation, due to their unique three-dimensional structures and their ability to promote a potentially rich array of weak noncovalent interactions. Herein, we report the rational design of metallacages with carborane functionality and cooperative dihydrogen binding sites for the highly selective capture of cyclohexane molecules. The metallacage 1, bearing the ligand 2,4,6-tris(4-pyridyl)-1,3,5-triazine (TPT), can produce cyclohexane with a purity of 98.5% in a single adsorption–desorption cycle from an equimolar mixture of benzene and cyclohexane. In addition, cyclohexene molecules can be also encapsulated inside the metallacage 1. This selective encapsulation was attributed to spatial confinement effects, C–H···π interactions, and particularly dihydrogen-bond interactions. This work suggests exciting future applications of carborane cages in supramolecular chemistry for the selective adsorption and separation of alkane molecules and may open up a new research direction in host–guest chemistry.

Herein, we have successfully achieved the stereoselective synthesis of two chiral radial [5]catenanes in a single step through the self-assembly of bidentate ligands containing l-alanine residues and binuclear half-sandwich organometallic rhodium(III)/iridium(III) clips. Remarkably, these two chiral radial [5]catenanes exhibit complex stereochemical structures as revealed by single-crystal X-ray diffraction. The eight binuclear units and eight bidentate ligands in their solid-state structures all exhibit a single planar chirality, and the interlocking between molecular macrocycles exhibits a single co-conformational mechanical helical chirality. This indicates that the introduction of the point chirality in the ligands enables the efficient stereoselective construction of mechanically interlocked molecules. Furthermore, by using ligands containing d-alanine residues, radial [5]catenanes with the opposite planar chirality and opposite co-conformational mechanical helical chirality have also been obtained.

The effect of boron addition (0.010, 0.015, and 0.020 wt.%) on the microstructure and mechanical properties of an additively manufactured superalloy was examined. The as-built microstructure was investigated by scanning electron microscopy and transmission electron microscopy. The results demonstrate that boron precipitates as M3B2boride at the grain boundary. The increase in boron content increases the amount of γ/γ′ eutectic and the size and fraction of M3B2boride. Boron creates nanoscale fine borides at grain boundaries, which significantly reinforces grain boundaries. The mechanical property analysis indicated that the addition of boron improved the tensile ductility at 760 °C and stress rupture properties at 760 °C/780 MPa. However, with the excessive addition of boron, the mechanical property was reduced.

In this study, high density electric current pulse (ECP) treatment was introduced instead of the conventional solution treatment, and the γ′ phase was completely dissolved under the ECP treatment within only several milliseconds at 1148 °C. Due to the extremely short treatment time and high cooling rate, the growth of γ-phase matrix grain and γ′ phase precipitate was effectively retarded. By comparing with the conventional heat process, the grain size of ECP treated sample was controlled to about 15 μm, the size of the re-precipitated γ′ phase reduced from 65 to 35 nm, and the number density of γ′ precipitate increased from 1.46 × 108to 3.03 × 108/mm2. The Vickers hardness, ultimate tensile strength and yield strength of the ECP treated sample were significantly improved. According to the theoretical derivation of kinetics, the ECP treatment introduces an extra electrical free energy which promoted the dissolution of γ′ phase. The ECP treatment may provide a new method for solution treatment of the Ni-based superalloy.

Darcy's law has been widely used to study the groundwater drainage process within an aquitard. However, non-Darcy flow is frequently encountered in laboratory and in situ investigations. With consideration of a sudden drop in boundary hydraulic heads, aquitard compaction characteristics and their sensitivities to the non-Darcy flow control variables were analyzed. The non-Darcy flow was found to retard groundwater drainage, and the retardation effects were much more significant at early-to-intermediate time points. Under this specific boundary condition, the time–compaction curve in a log–log graph at early time points was found to be close to a straight line, whose slope can be used to indirectly evaluate the extent of the non-Darcy effect. A non-Darcy flow-based type curve method was developed for estimating aquitard hydraulic conductivity (K) and skeletal specific storage (Ss), and this method was used to interpret the time–compaction data recorded in a laboratory experiment. The tested aquitard was determined to be associated with non-Darcy flow due to the fact that the time–compaction curve deviated from the Darcy's law-based theoretical curve. Darcy's law resulted in an underestimated K. In contrast, the estimated Sswas almost unaffected by the flow state, if the observation lasted long enough to reach final steady compaction.

Although a large number of novel supramolecular topologies featuring half-sandwich [Cp*Rh] units have been reported, investigations into the properties of these architectures are astoundingly rare. In addition, the bidentate ligands employed to prepare these species have remained relatively homogeneous (i.e., symmetrical bis(pyri-4-dyl) ligands). To address these paucities in the field, the novel unsymmetrical ligand L2and the rarely reported pyri-3-dyl ligand L3, all bearing aromatic phenazine groups (an N-heterocyclic analog of anthracene), were synthesized in addition to the common symmetrical pyri-4-dyl L1. [3]Catenane, [2]catenane, and Borromean rings assemblies were constructed successfully by the self-assembly of L1with different building blocks. Afterward, ligand L2was applied to prepare two novel molecular-tweezer-like compounds. Lastly, a twisted [2]catenane (relative to the [2]catenane constructed using L1) and a sandwiched metallarectangle were obtained using L3. π–π stacking interactions were observed to play a significant role in stabilizing these topologies, which also promoted nonradiative migration and triggered photothermal conversion in both the solution and the solid state. In the solution state, a clear rule of thumb was derived whereby the NIR photothermal conversion efficiency increased as the π–π stacking increased, and a very high photothermal conversion efficiency (35.5–62.4%) was observed. In addition, this family of half-sandwich-based assemblies also exhibited good photothermal conversion properties in the crystalline and noncrystal powder states. This research provides a novel method to synthesize excellent NIR photothermal conversion materials featuring half-sandwich [Cp*Rh] units and points to potential applications in the near future.

In this study, a kind of Ni-based superalloy specially designed for additive manufacturing (AM) was investigated. Thermo-Calc simulation and differential scanning calorimetry (DSC) analysis were used to determine phases and their transformation temperature. Experimental specimens were prepared by laser metal deposition (LMD) and traditional casting method. Microstructure, phase constitution and mechanical properties of the alloy were characterized by scanning electron microscopy (SEM), transmission scanning electron microscopy (TEM), X-ray diffraction (XRD) and tensile tests. The results show that this alloy contains two basic phases, γ/γ’, in addition to these phases, at least two secondary phases may be present, such as MC carbides and Laves phases. Furthermore, the as-deposited alloy has finer dendrite, its mean primary dendrite arm space (PDAS) is about 30–45 μm, and the average size of γ’ particles is 100–150 nm. However, the dendrite size of the as-cast alloy is much larger and its PDAS is 300–500 μm with secondary and even third dendrite arms. Correspondingly, the alloy displays different tensile behavior with different processing methods, and the as-deposited specimen shows better ultimate tensile stress (1,085.7±51.7 MPa), yield stress (697±19.5 MPa) and elongation (25.8%±2.2%) than that of the as-cast specimen. The differences in mechanical properties of the alloy are due to the different morphology and size of dendrites, γ’, and Laves phase, and the segregation of elements, etc. Such important information would be helpful for alloy application as well as new alloy development.

A corrosion-resistant and wear-resistant coating was prepared on the inner wall of copper tube by centrifugal self-propagating melting. The surface morphology, composition and phase composition of the ceramic lining FGM coating were analyzed by XRD and SEM, and the synthesis mechanism of the ceramic coating was studied. The results show that the functionally gradient coating is composed of three layers: ceramic inner layer, metal transition layer and copper substrate layer. The surface of ceramic lining is smooth and dense, which is mainly composed of Al2O3, CaF2 and a small amount of Fe Al spinel. The results show that the alumina phase is dendrite like and grows outward perpendicular to the tube wall, and the low melting point phase is evenly distributed in the dendrite gap, which effectively improves the density of the ceramic layer.

Background: Testicular Germ Cell Tumor (TGCT) is the most common malignant tumor in young men, but there is a lack of a prediction model to evaluate the prognosis of patients with TGCT. Objective: To explore the prognostic factors for Progression-Free Survival (PFS) and construct a nomogram model for patients with early-stage TGCT after radical orchiectomy. Methods: Patients with TGCT from The Cancer Genome Atlas (TCGA) database were used as the training cohort; univariate and multivariate cox analysis was performed. A nomogram was constructed based on the independent prognostic factors. Patients from the Nanfang Hospital affiliated with Southern Medical University were used as the cohort to validate the predictive ability using the nomogram model. Harrell's concordance index (C-index) and calibration plots were used to evaluate the nomogram. Results: A total of 110 and 62 patients with TGCT were included in the training cohort and validation cohort, respectively. Lymphatic Vascular Invasion (LVI), American Joint Committee on Cancer (AJCC) stage and adjuvant therapy were independent prognostic factors in multivariate regression analyses and were included to establish a nomogram. The C-index in the training cohort for 1- , 3-, and 5-year PFS were 0.768, 0.74, and 0.689, respectively. While the C-index for 1-, 3-, and 5- year PFS in the external validation cohort were 0.853, 0.663 and 0.609, respectively. The calibration plots for 1-, 3-, and 5-year PFS in the training and validation cohort showed satisfactory consistency between predicted and actual outcomes. The nomogram revealed a better predictive ability for PFS than AJCC staging system. Conclusion: The nomogram as a simple and visual tool to predict individual PFS in patients with TGCT could guide clinicians and clinical pharmacists in therapeutic strategy.

Two molecular metalla-knots containing over 500 non-hydrogen atoms (especially 16 RhIIIions) and one molecular Borromean ring were obtained in high yields facilitated by multiple intermolecular interactions between their components. The syntheses rely on the strategic selection of the nonlinear dipyridyl ligand 2,7-di(pyridin-4-yl)-9H-fluorene (L1) as precursor, and the structures of the assemblies were confirmed by detailed X-ray crystallographic analysis. Subsequently, replacing L1with the bulkier ligand 4,4′-(9,9-dimethyl-9H-fluorene-2,7-diyl)dipyridine (L2) led to the formation of three tetranuclear metallocycles in high yields on account of the weakened π–π stacking interactions between the naphthacene/anthracene and fluorene moieties, which in turn confirmed the significance of stacking interactions in the construction of the molecular 818metalla-knots and the molecular Borromean ring.

Targeting nuclear factor kappa B (NF‐κB) signaling pathway has become a promising strategy for the development of new antitumor drugs. In this paper, we found that anti‐infection drug furazolidone (FZD) could significantly inhibit NF‐κB‐driven luciferase activity, and FZD could markedly inhibit both of the constitutive and tumor necrosis factor‐α (TNFα)‐triggered phosphorylation of NF‐κB p65 in small cell lung cancer (SCLC). Further studies revealed that FZD inhibited the expression of inhibitor of kappa B kinase β (IKKβ) in SCLC cells. In addition, we found that FZD had significant antitumor activities in SCLC cells. FZD could markedly suppress the cell viability of SCLC cells dose‐dependently, and FZD could significantly induce the cleavages of poly ADP‐ribose polymerase (PARP) and Caspase3, the biomarkers of cell apoptosis, in SCLC cells. The flow cytometry also revealed that FZD induced cell apoptosis in SCLC cells. Finally, we also found that overexpression of constitutively activated IKKβ could significantly abolish FZD‐induced cell growth inhibition in SCLC cells, which further confirmed that FZD displayed its anti‐SCLC activity through regulating NF‐κB signaling pathway.

Molecular figure-eight knot (notation: 41) is extremely rare and presents great synthetic challenge due to its essentially complicated entanglement. To solve this synthetic problem, a quadruple stacking strategy was developed. Herein, we report the efficient self-assembly of figure-eight knots induced by quadruple stacking interactions, through the combination of four carefully selected naphthalenediimide (NDI)-based pyridyl ligands and Cp*Rh building blocks bearing large conjugated planes in a single-step strategy. Notably, slight size adjustment of the Cp*Rh units was found to affect the stability of the figure-eight knots in methanol. Additionally, reversible structural transformations between these figure-eight knots and corresponding metallorectangles could be achieved by concentration changes and solvent- and guest-induced effects. X-ray crystallographic data and NMR spectroscopy provide full confirmation of these phenomena.

Two novel fac-Re(CO)3-based rectangles {[(CO)3Re(μ-Cl)2Re(CO)3]2(μ-L)2} (1) and {[(CO)3Re(μ-OC4H9)2Re(CO)3]2(μ-L)2}(2) based on new photochromic dithienylethene-containing ligand 2,7-di(pyridin-4-yl)-9,10-bis(5-chloro-2-methylthien-3-yl)-phenanthrene (L) were prepared. They displayed varying photochromic properties both in solution and in the single-crystal state. Through a judicious choice of the bridging ligands along the short sides of the rectangles, the photophysical and electrochemical properties of the complexes could also be readily tuned.

With the help of retrosynthetic analysis, we have realized the highly anticipated stereoselective synthesis of a topologically chiral Solomon link, by taking advantage of coordination-driven self-assembly and chiral induction by axially chiral ligands. Combination of the ligands (Ror S)-2,2'-diethoxy-1,1'-binaphthyl-6,6'-bis(4-vinylpyridine) (R-Lor S-L) with the binuclear iridium complex [Cp*2Ir2(DHBQ)(OTf)2] (Ir-B(OTf)2, H2DHBQ = 2,5-dihydroxy-1,4-benzoquinone) allows diastereoselective synthesis of the topological enantiomers P(Ir-1P) or M(Ir-1M) of a Solomon link, respectively. The main driving force for the formation of the Solomon link is the π-π interactions between chiral ligands.

• As-extruded Mg–6Al–4Zn–3Sn alloy exhibits superior combination of high strength (∼366 MPa) and elongation (∼19 %). • Sn is proven to play an effective contribution to the simultaneous improvement in strength and ductility. • The strong strain hardening ability comes from the facilitation of pyramidal < c + a > slip with Sn addition. Commercial wrought Mg alloys normally contain low alloying contents to ensure good formability. In the present work, high-alloyed Mg-6Al-4Zn- x Sn (x = 1, 2 and 3 wt.%, respectively) alloys were fabricated by extrusion. Hereinto, Sn was proven to play an effective contribution to simultaneous improvement in strength and ductility that are traditional trade-off features of synthetic materials. It was found that the average grain size of those alloys decreases significantly from ∼11 to ∼4 μm as a function of Sn contents increasing from 0 to 3 wt.%, while the amounts of Mg 2 Sn and Mg 17 Al 12 particles continuously increase. More importantly, the addition of Sn leads to the transformation of dominated deformation modes from { 10 1 ¯ 2 } extension twinning (1 wt.%) to pyramidal < c + a > slip (3 wt.%) during tensile tests along the extrusion direction at room temperature. The advantageous combination of ultimate tensile strength (∼366 MPa) and elongation (∼19 %) in Mg-6Al-4Zn-3Sn alloy is mainly attributed to the strong strain hardening ability induced by the enhanced activity of non-basal < c + a > slip. This work could provide new opportunities for the development of high-alloyed wrought Mg alloys with promising mechanical properties. [ABSTRACT FROM AUTHOR]

Cobalt-based coatings were fabricated on FV520B substrate by plasma cladding technology. Evolution of performance and microstructure of cobalt-based coating and interface under thermomechanical coupling action was studied. Results elucidated that the nano-hardness of the compressed material changes obviously, but the interface structure can maintain good hardness stability. Wear resistance of coatings subjected to high-temperature compression is significantly enhanced, and the higher compression temperature further increases the wear resistance of the coating. Torsion and deformation of microstructure occur with the increasing of deformation amount. Obvious plastic deformation occurs at the interface. The original dendrite morphology in the coating completely disappeared with the increase of temperature and deformation amount, and there is a series of microstructure changes contribute to the improvement of performance.

Herein, we describe how to utilize dihydrogen bond interactions to achieve alkane recognition and hexane isomer separation. A series of metallacycles based on carborane backbones are presented herein, revealing interdependent B–Hδ−···Hδ+–C proton–hydride interactions. The metallacycles take advantage of these dihydrogen bond interactions for the separation of hexane isomers. We show that the metallacycle 3a, bearing 1,4-di(4-pyridyl)benzene (DPB), can produce n-hexane with a purity of >99% in a single adsorption–desorption cycle from an equimolar mixture of all five isomers of hexane. The isomers 2-methylpentane and 3-methylpentane can be selectively absorbed by metallacycle 4a, which bears 1,2-di(4-pyridyl)ethylene (DPE). The size of the metallacycle, C–H···π interactions, and particularly B–Hδ−···Hδ+–C interactions are the main forces governing the extent of hexane recognition. This work provides a promising principle for the design of supramolecular coordination complexes (SCCs) for the separation of alkanes.

Biodegradable vascular stent is mainly made of materials that can be naturally decomposed. After implantation into human blood vessels, the vascular stent can be continuously degraded over time and eventually disappear completely after the treated blood vessels are healed and support from the vascular stent is not needed. The vascular stent materials used in clinic should have good biocompatibility, which mainly involves blood compatibility and cell compatibility. In terms of cell compatibility, the influence of materials on cell growth should be observed. The various biological materials should have good anticoagulant character, so as to reduce the tendency of thrombosis and avoid the occurrence of various risk events in clinical treatment.

Biodegradable vascular stent is mainly made of materials that can be naturally decomposed. Magnesium and its alloys have excellent mechanical properties and biocompatibility. The vascular stent made of magnesium and its alloys has the unique advantages of strength of metal scaffolds and bioabsorbability of degradable polymer scaffolds. Due to the special microenvironment inside the blood vessels, the stent should have good resistance against corrosion. After implantation of metal materials for human tissue repair, the surface oxidation film spontaneously formed in the air will react with the human physiological environment. The nature of the interface between materials and tissues will have a certain impact on the corrosion resistance of metals and the degree of metal ion release, thus determining the biocompatibility of materials.

Impairment in semantic association has been reported in bipolar disorder (BD) and schizophrenia (SZ) patients and could underlie abnormal speech patterns in both disorders. In this study, we compared the electrophysiological semantic processing features in patients with these two disorders. Participants (n= 61; BD = 19; SZ = 19; healthy controls [HCs] = 23) were administered a semantic judgment task and event‐related potentials (ERPs) were recorded. Responses of the two patient groups were significantly slower than HCs, but comparable behavioral semantic priming effects were observed in both patient groups. The N400 priming effect was observed in all groups, with a delayed peak in the two patient groups. The N400 effect was enhanced for both BD and SZ patients over the left frontal and frontal pole region, but SZ patients showed additional reduction of N400 over the right posterior and occipital regions. The N400 mean amplitudes for related targets correlated with less severe negative symptoms in patients with SZ. Discriminant functional analysis using reaction time and N400 measures successfully classified 82% of the participants into their respective clinical groups. These results suggest that patients with BD and SZ have both overlapping and distinctive semantic processing dysfunction. These findings are consistent with the continuum conceptualization of these disorders, but also offer some support for the traditional Kraepelinian dichotomy.

Al-Mg-Si (AA6xxx) series alloys have been used widely in automotive industry for lightweight purpose. This work focuses on developing a short process for manufacturing Al-0.5Mg-1.3Si (wt.%) alloy sheets with good mechanical properties. Hereinto, a preparation route without homogenization was proposed on the basis of sub-rapid solidification (SRS) technique. The sample under SRS has fine microstructure and higher average partition coefficients of solute atoms, leading to weaker microsegregation owing to the higher cooling rate (160 °C/s) than conventional solidification (CS, 30 °C/s). Besides, Mg atoms tend to be trapped in Al matrix under SRS, inducing suppression of Mg 2 Si, and promoting generation of AlFeSi phase. After being solution heat treated (T4 state), samples following the SRS route have lower yield strength compared with that by CS route, indicating better formability in SRS sample. After undergoing pre-strain and artificial aging (T6 state), the SRS samples have comparable yield strength to CS samples, satisfying the service requirements. This work provides technological support to industrially manufacture high performance AA6xxx series alloys with competitive advantage by a novel, short and low-cost process, and open a door for the further development of twin-roll casting based on SRS technique in industries. [ABSTRACT FROM AUTHOR]

ABSTRACTThree kinds of AlCoFeNiTiZr high-entropy alloy films with different elements ratios were prepared using magnetron sputtering. The films were composed of fcc solid solution phases and amorphous phases with typical uniform polycrystal microstructure. The anticorrosion performances of the films were tested in a NaCl solution. The changes of microstructures and composition were quantitatively characterised by XPS, SEM and TEM. During the corrosion reaction process there was a decrease in the contents of Al, Ti, Zr and Fe elements. The increase in Fe-Co-Ni content lead to an increase of passivation area, and a subsequent increase in corrosion potential (Ecorr) and a decrease in the corrosion current density (Icorr). A decrease in the crystal lattice distortion, vacancy, dislocation and grain boundary segregation was also noted increasing corrosion resistance. Additionally, both the grain refinement and the total grain boundary length in the film reduced, and as a result the corrosion resistance improved.

Polyoxometalates (POMs), emerging as a new class of porous molecular materials, play a promising role in homo- and heterogeneous catalysis. Among them, noble-metal-decorated POMs have a profound impact as catalytic materials. Thus, it is imperative to design and structurally explore new catalysts including noble metals. Herein, two new clusters, H3[(Cp*Rh)4PMo8O32]·14H2O (1) and H5[Na2(Cp*Ir)4PMo8O34]·13H2O (2) (Cp* = pentamethylcyclopentadienyl), based on a heterooctamolybdate anionic core were successfully obtained via a one-pot reaction using [Cp*MCl2]2[M = Rh (1) and Ir (2)] and Na2MoO4in acidic conditions. Compounds 1and 2were well characterized in the solid state by single-crystal X-ray diffraction, IR, and thermogravimetric analysis and in solution by UV–vis, electrospray ionization mass spectrometry, and electrochemistry. Compounds 1and 2represent an important class of structurally isolated organometallic POM-based clusters that were successfully nanostructured onto Ni foam and electrochemically reduced after 48 h of electrolysis to M/MoO2, where M = Rh (3) and Ir (4), nanocomposite hybrid materials on a Ni foam surface in a 0.1 M KOH solution. The modified electrocatalysts (3and 4) show efficient hydrogen evolution reaction activities almost comparable to those of high-grade Pt/C at 0.1 M KOH. The nanostructured POMs [1- and 2@NF (Ni foam)] and their corresponding reduced products (3and 4) were observed by scanning electron microscopy, energy-dispersive X-ray spectroscopy, powder X-ray diffraction, and X-ray photoelectron spectroscopy and further proven by transmission electron microscopy (TEM) and high-resolution TEM.

The (La0.5Eu0.25Y0.25)2Zr2O7(LEYZ) ceramic powder for spraying was prepared and synthesised by combining spray granulation and solid phase reaction phase, and a double ceramic layer structure with (La0.5Eu0.25Y0.25)2Zr2O7ceramic surface coating and YSZ intermediate coating was prepared by atmospheric plasma spraying. Experimental characterisation revealed that the moulding state of spray granulated powders was significantly influenced by the solid content. When the solid content is small, the viscosity of the slurry is insufficient, and the prepared powder has poor formability and small overall particle size. When the solid content is large, the slurry is too viscous, which easily leads to unfavourable conditions such as sticky walls. The best formability of the pelletised powder was obtained with a solid content of 55 wt-% and a binder content of 2.0 wt-%. Compared with La2Zr2O7(LZ) ceramics, the fracture toughness of the rare-earth co-doped modified LEYZ ceramic coating was increased by 8.4% and the bond strength was increased by 49.9%, showing good toughness and crack resistance. Moreover, LEYZ coating has significantly better resistance to solid phase particle erosion than LZ coating, with 46.3% and 45.4% reduction in erosion rate at 45° and 90°, respectively.

A template-free Cp*Ir-based molecular Solomon link and an unusual trefoil knot induced by stacking interactions were realized via selection of the nonrigid dipyridyl ligand 4,4′-bis(pyridin-4-ylmethyl)-1,1′-biphenyl (BpmBp). In addition, a novel heterobimetallic tetranuclear (IrIII2+ AgI2) complex featuring argentophilic interaction was synthesized in high yield. Remarkably, the reversible topological transformation between the Solomon link and an unusual trefoil knot can be achieved by utilizing the chemical reactivity of silver(I) ions under mild conditions, as demonstrated by a detailed X-ray crystallographic study.

Chlorophylls, known as the key building blocks of natural light-harvesting antennae, are essential to utilize solar energy from visible to near-infrared (NIR) region during the photosynthesis process. The fundamental studies for the relationship between structure and photophysical properties of chlorophylls disclosed the importance of β-peripheral modification and thus boosted the fast growth of NIR absorbing/emissive porphyrinoids via altering the extent of π-conjugation and the degree of distortion from the planarity of macrocycle. Despite the tremendous progress made in various porphyrin-based synthetic models, it still remains a challenge to precisely modulate photophysical properties through fine-tuning of β-peripheral structures in the way natural chlorophylls do. With this in mind, we initiated a program and focused on meso-C6F5-substituted porpholactone (F20TPPL), in which one β-pyrrolic double bond was replaced by a lactone moiety, as an attractive platform to construct the bioinspired library of NIR porphyrinoids.

This study aims to investigate the promotion effect of twinning-induced nucleation vs the inhibition effect of Mg 17 Al 12 particles pinning for recrystallization, achieved through gradient rolling for Mg‒3Al‒1Zn (AZ31) and Mg‒9Al‒1Zn (AZ91) alloys as well as pure Mg. Through gradient rolling, a transition zone from the initial to deformed microstructure undergoing varying thickness reductions was obtained in the same sample, where the evolution of deformation twins and second phase can be examined precisely and continuously. During hot deformation, dynamic recrystallized (DRXed) grains tended to originate from {10 1 ¯ 1}-{10 1 ¯ 2} double twins, whose nucleation was significantly restricted by increasing Al content and hence recrystallization can be rarely triggered in AZ91 alloy. Concurrently, the size and volume fraction of Mg 17 Al 12 particles changed via dissolution and re-precipitation, leading to finer average size and higher volume fraction, which produced stronger pinning effect and hindered dynamic recrystallization significantly. The current study provides insights into the mechanisms responsible for dynamic recrystallization behavior during hot rolling in Mg‒Al‒Zn alloys. [ABSTRACT FROM AUTHOR]

Titanium nitride (TiN) is a metal-like refractory material that can be used as a substitution for metals in many applications. In this paper, we report the use of an ultra-thin TiN film in the Salisbury screen structure to spectral selectively absorb visible light for forming an optical color filter. The ultra-thin TiN film functions as a partial reflector as well as a protection capping layer in the structure. Spectral selective perfect absorption color filters with TiN–ZnO–Al multilayer films were fabricated and characterized.