Preferential Formation of Mono‐Metallofullerenes Governed by the Encapsulation Energy of the Metal Elements: A Case Study on Eu@C2n (2n=74–84) Revealing a General Rule

Encapsulating one to three metal atoms or a metallic cluster inside fullerene cages affords endohedral metallofullerenes (EMFs) classified as mono‐, di‐, tri‐, and cluster‐EMFs, respectively. Although the coexistence of various EMF species in soot is common for rare‐earth metals, we herein report that europium tends to prefer the formation of mono‐EMFs. Mass spectroscopy reveals that mono‐EMFs (Eu@C_2n) prevail in the Eu‐containing soot. Theoretical calculations demonstrate that the encapsulation energy of the endohedral metal accounts for the selective formation of mono‐EMFs and rationalize similar observations for EMFs containing other metals like Ca, Sr, Ba, or Yb. Consistently, all isolated Eu‐EMFs are mono‐EMFs, including Eu@D_3h(1)‐C₇₄, Eu@C_2v(19138)‐C₇₆, Eu@C_2v(3)‐C₇₈, Eu@C_2v(3)‐C₈₀, and Eu@D_3d(19)‐C₈₄, which are identified by crystallography. Remarkably, Eu@C_2v(19138)‐C₇₆ represents the first Eu‐containing EMF with a cage that violates the isolated‐pentagon‐rule, and Eu@C_2v(3)‐C₇₈ is the first C₇₈‐based EMF stabilized by merely one metal atom.     

Covalent Organic Framework for Improving Near‐Infrared Light Induced Fluorescence Imaging through Two‐Photon Induction

Fluorescent materials exhibiting two‐photon induction (TPI) are used for nonlinear optics, bioimaging, and phototherapy. Polymerizations of molecular chromophores to form π‐conjugated structures were hindered by the lack of long‐range ordering in the structure and strong π–π stacking between the chromophores. Reported here is the rational design of a benzothiadiazole‐based covalent organic framework (COF) for promoting TPI and obtaining efficient two‐photon induced fluorescence emissions. Characterization and spectroscopic data revealed that the enhancement in TPI performance is attributed to the donor‐π‐acceptor‐π‐donor configuration and regular intervals of the chromophores, the large π‐conjugation domain, and the long‐range order of COF crystals. The crystalline structure of TPI‐COF attenuates the π–π stacking interactions between the layers, and overcomes aggregation‐caused emission quenching of the chromophores for improving near‐infrared two‐photon induced fluorescence imaging.     

Unraveling the Impact of Gold(I)–Thiolate Motifs on the Aggregation‐Induced Emission of Gold Nanoclusters

Aggregation‐induced emission (AIE) provides an efficient strategy to synthesize highly luminescent metal nanoclusters (NCs), however, rational control of emission energy and intensity of metal NCs is still challenging. This communication reveals the impact of surface Au^I‐thiolate motifs on the AIE properties of Au NCs, by employing a series of water‐soluble glutathione (GSH)‐coordinated Au complexes and NCs as a model ([Au₁₀SR₁₀], [Au₁₅SR₁₃], [Au₁₈SR₁₄], and [Au₂₅SR₁₈]^?, SR=thiolate ligand). Spectroscopic investigations show that the emission wavelength of Au NCs is adjustable from visible to the near‐infrared II (NIR‐II) region by controlling the length of the Au^I‐SR motifs on the NC surface. Decreasing the length of Au^I‐SR motifs also changes the origin of cluster luminescence from AIE‐type phosphorescence to Au⁰‐core‐dictated fluorescence. This effect becomes more prominent when the degree of aggregation of Au NCs increases in solution.     

Chitosan‐modified graphene oxide as a modifier for improving the structure and performance of forward osmosis membranes

Chitosan (CS) with good hydrophilicity and charged property was used to modify graphene oxide (GO), the obtained GO‐CS was used as a novel modifier to fabricate thin film composite forward osmosis (FO) membranes. The results revealed that the amino groups on CS reacted with carboxyl groups on GO, and the lamellar structure of the GO nanosheets was peeled off by CS, resulting in the reducing of their thicknesses. The GO‐CS improved the hydrophilicity of polyethersulfone (PES) substrate, and their contact angles decreased to 64° with the addition of GO‐CS in the substrate. GO‐CS also increased the porosity of the substrate and surface roughness of FO membrane, thereby optimizing the water flux and reverse salt flux of FO membrane. The average water flux of the FO membrane reached the optimal flux of 21.34 L/(m² h) when GO‐CS addition was 0.5 wt%, and further addition of GO‐CS to the substrate would decrease the water flux of FO membrane, and the reverse salt flux also decreased to the lowest value of 2.26 g/(m² h). However, the salt rejection of the membrane increased from 91.4% to 95.1% when GO‐CS addition increased from 0.5 to 1.0 wt% under FO mode using 1 mol/L sodium chloride (NaCl) solution as draw solution (DS). In addition, high osmotic pressure favored water permeation, and at the same concentration of DS, magnesium chloride (MgCl₂) exhibited better properties than NaCl. These results all suggested that GO‐CS was a good modifier to fabricate FO membrane, and MgCl₂ was a good DS candidate.     

Influence of the molding angle on tensile properties of FDM parts with orthogonal layering

Fused deposition molding (FDM) is one of the most widely used three‐dimensional (3D) printing technologies. This paper explores the influence of the forming angle on the tensile properties of FDM specimens. Orthogonal layering details were studied through experiments, theory, and finite element simulations. The stiffness and strength of the specimens were analyzed using the classical laminated plate theory and the Tsai–Wu failure criterion. The experimental process was simulated using finite element simulations. Results show that it is feasible to predict the stiffness and strength of FDM specimens using classical laminated plate theory and the Tsai–Wu failure criterion. A molding angle of 45° leads to specimens with maximized tensile properties. Numerical simulations show that changing the molding angle changes the internal stress and deformation fields inside samples, leading to FDM samples with different mechanical properties due to the orthogonal layers at different molding angles.     

The effect of 3D printing on the morphological and mechanical properties of polycaprolactone filament and scaffold

Three‐dimensional (3D) printing becomes an attractive technique to fabricate tissue engineering scaffolds through its high control on fabrication and repeatability using the printing parameters. This technique can be combined by the finite element method (FEM), and tissue‐specific scaffolds with desirable morphological and mechanical properties can be designed and manufactured. In this study, the influential 3D printing parameters on the morphological and mechanical properties of polycaprolactone (PCL) filament and scaffold were studied experimentally and numerically. First, the effects of printing parameters and process on the properties of extruded PCL filament were investigated. Then, using FEM, the effects of filament specifications on the overall characteristics of the scaffold were evaluated. Results showed that both the printing process in terms of resting time and remaining time and the printing parameters like pressure, printing speed, and printing path length have influenced the filament properties. In addition, both the filament diameter and elastic modulus had significant effects on the properties of scaffold especially, a 20% increase in the filament diameter caused the scaffold compressive elastic modulus to rise by around 72%. It is concluded that the printing parameters and process must be tuned very well in fabricating scaffolds with the desired morphology and mechanical property.     

Wearable Multiparameter Platform Based on AlGaN/GaN High‐electron‐mobility Transistors for Real‐time Monitoring of pH and Potassium Ions in Sweat

Biosensors based on field‐effect transistor (FET) structures have attracted considerable attention because they offer rapid, inexpensive parallel sensing and ultrasensitive label‐free detection. However, long‐term repeatable detection cannot be performed, and Ag/AgCl reference electrode design is complicated, which has hindered FET biosensors from becoming truly wearable health‐monitoring platforms. In this paper, we propose a novel wearable detection platform based on AlGaN/GaN high‐electron‐mobility transistors (HEMTs). In this platform, a sweatband was used to continuously collect sweat, and a pH detecting unit and a potassium ion detecting unit were formed by modifying different sensitive films to realize the long‐term stable and repeatable detection of pH and potassium ions. Experimental data show that the wearable detection platform based on AlGaN/GaN HEMTs has good sensitivity (pH 3–7 sensitivity is 45.72 μA/pH; pH 7.4–9 sensitivity is 51.073 μA/pH; and K⁺ sensitivity is 4.94 μA/lgα_K⁺), stability (28 days) and repeatability (the relative standard deviation (RSD) of pH 3–7 sensitivity is 2.6 %, the RSD of pH 7.4–9 sensitivity is 2.1 %, and the RSD of K⁺ sensitivity is 7.3 %). Our newly proposed wearable platform has excellent potential for predictive analytics and personalized medical treatment.     

Tuning the mechanical properties and degradation properties of polydioxanone isothermal annealing

Polydioxanone (PPDO) is synthesized by ring-opening polymerization of p-dioxanone, using stannous octoate as the catalyst. The polarized optical micrograph (POM) shows thes pherulite growth rate of PPDO decreases with an increase in the isothermal crystallization temperature. PPDO is compression-molded into bars, and PPDO bars are subjected to isothermal annealing at a range of temperatures (Ta = 50, 60, 70, 80, 90, and 100 °C), and correspond to three different annealing times (ta = 1h, 2h, 3h). The effect on PPDO is investigated by using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), X-ray diffraction (XRD), and scanning electron microscopy (SEM). With an increase in Ta and ta, the grain size and the degree of crystallinity also increase. Meanwhile, the tensile strength is significantly improved. The PPDO bars (90 °C, 2 h) reach the maximum crystallinity (57.21%) and the maximum tensile strength (41.1 MPa). Interestingly, the heat treatment process does not result in serious thermal degradation. It is observed that the hydrolytic degradation of the annealed PPDO is delayed to some extent. Thus, annealed PPDO might have potential applications, particularly in the fields of orthopedic fixation and tissue engineering.     

Coptis chinensis Franch Directly Inhibits Proteolytic Activation of Kallikrein 5 and Cathelicidin Associated with Rosacea in Epidermal Keratinocytes

Rosacea is a common and chronic inflammatory skin disease that is characterized by dysfunction of the immune and vascular system. The excessive production and activation of kallikerin 5 (KLK5) and cathelicidin have been implicated in the pathogenesis of rosacea. Coptis chinensis Franch (CC) has been used as a medicinal herb in traditional oriental medicine. However, little is known about the efficacy and mechanism of action of CC in rosacea. In this study, we evaluate the effect of CC and its molecular mechanism on rosacea in human epidermal keratinocytes. CC has the capacity to downregulate the expression of KLK5 and cathelicidin, and also inhibits KLK5 protease activity, which leads to reduced processing of inactive cathelicidin into active LL-37. It was determined that CC ameliorates the expression of pro-inflammatory cytokines through the inhibition of LL-37 processing. In addition, it was confirmed that chitin, an exoskeleton of Demodex mites, mediates an immune response through TLR2 activation, and CC inhibits TLR2 expression and downstream signal transduction. Furthermore, CC was shown to inhibit the proliferation of human microvascular endothelial cells induced by LL-37, the cause of erythematous rosacea. These results demonstrate that CC improved rosacea by regulating the immune response and angiogenesis, and revealed its mechanism of action, indicating that CC may be a useful therapeutic agent for rosacea.     

Three‐dimensional Octameric Assembly of Icosahedral M13 Units in [Au8Ag57(Dppp)4(C6H11S)32Cl2]Cl and its [Au8Ag55(Dppp)4(C6H11S)34][BPh4]2 Derivative

The high‐dimensional (that is, three‐dimensional (3D)) assembly of nanomaterials is an effective means of improving their properties; however, achieving this assembly at the atomic level remains challenging. Herein, we obtained a novel nanocluster, [Au₈Ag₅₇(Dppp)₄(C₆H₁₁S)₃₂C_l2]Cl (Dppp=1,3‐bis(diphenylphosphino)propane) showing a 3D octameric assembly mode involving the kernel penetration of eight complete icosahedral Au@Ag₁₀Au₂ units for the first time. The atomically precise structure was determined by single‐crystal X‐ray diffraction, and further confirmed by thermogravimetric analysis, X‐ray photoelectron spectroscopy, and electrospray ionization mass spectrometry measurements. Furthermore, ligand‐induced transformation prompted the conversion of [Au₈Ag₅₇(Dppp)₄(C₆H₁₁S)₃₂Cl₂]Cl, with complete octameric fusion into [Au₈Ag₅₅(Dppp)₄(C₆H₁₁S)₃₄][BPh₄]₂, with incomplete octameric fusion. These observations will hopefully facilitate further research on the assembly of M₁₃ nanobuilding blocks.