Fully recyclable and tough thermoplastic elastomers from simple bio-sourced δ-valerolactones.

While a large number of chemically recyclable thermoplastics have been developed in recent years, technologically important thermoplastic elastomers (TPEs) that are not only bio-based and fully recyclable but also exhibit mechanical properties that can rival or even exceed those petroleum-based, non-recyclable polyolefin TPEs are critically lacking. The key challenge in developing chemically circular, bio-based, high-performance TPEs rests on the complexity of TPE's block copolymer (BCP) structure involving block segments of different suitable monomers required to induce self-assembled morphologies responsible for performance as well as the control and monomer compatibility in their synthesis and the selectivity in their depolymerization. Here we demonstrate the utilization of bio-sourced δ-valerolactone (δVL) and its simple α-alkyl-substituted derivatives to produce all δVL-based polyester tri-BCP TPEs, which exhibit not only complete (closed-loop) chemical recyclability but also excellent toughness that is 2.5-3.8 times higher than commercial polyolefin-based TPEs. The visualized cylindrical morphology formed via crystallization-driven self-assembly in the new all δVL tri-BCP is postulated to contribute to the excellent TPE property.

[Effect of 2-phenylethyl-beta-glucopyranoside isolated from Huaizhong No. 1 Rehmannia glutinosa on hypoxic pulmonary hypertension by regulating PI3K/Akt/m TOR/HIF-1α pathway].

The study investigated the protective effect and mechanism of 2-phenylethyl-beta-glucopyranoside(Phe) from Huaizhong No.1 Rehmannia glutinosa on hypoxic pulmonary hypertension(PH), aiming to provide a theoretical basis for clinical treatment of PAH. Male C57BL/6N mice were randomly divided into normal group, model group, positive drug(bosentan, 100 mg·kg~(-1)) group, and low-and high-dose Phe groups(20 and 40 mg·kg~(-1)). Except for the normal group, all other groups were continuously subjected to model induction in a 10% hypoxic environment for 5 weeks, with oral administration for 14 days starting from the 3rd week. The cardiopulmonary function, right ventricular pressure, cough and asthma index, lung injury, cell apoptosis, oxidative stress-related indicators, immune cells, and phosphatidylinositol 3-kinase(PI3K)/protein kinase B(Akt)/mammalian target of rapamycin(mTOR)/hypoxic inducible factor 1α(HIF-1α) pathway-related proteins or mRNA levels were examined. Furthermore, hypoxia-induced pulmonary arterial smooth muscle cell(PASMC) were used to further explore the mechanism of Phe intervention in PH combined with PI3K ago-nist(740Y-P). The results showed that Phe significantly improved the cardiopulmonary function of mice with PH, decreased right ventricular pressure, cough and asthma index, and lung injury, reduced cell apoptosis, oxidative stress-related indicators, and nuclear levels of phosphorylated Akt(p-Akt) and phosphorylated mTOR(p-mTOR), inhibited the expression levels of HIF-1α and PI3K mRNA and proteins, and maintained the immune cell homeostasis in mice. Further mechanistic studies revealed that Phe significantly reduced the viability and migration ability of hypoxia-induced PASMC, decreased the expression of HIF-1α and PI3K proteins and nuc-lear levels of p-Akt and p-mTOR, and this effect was blocked by 740Y-P. Therefore, it is inferred that Phe may exert anti-PH effects by alleviating the imbalance of oxidative stress and apoptosis in lung tissues and regulating immune levels, and its mechanism may be related to the regulation of the PI3K/Akt/mTOR/HIF-1α pathway. This study is expected to provide drug references and research ideas for the treatment of PH.

Design, Preparation, and Mechanical Property Study of Polylactic Acid/Ca2BO3Cl: Eu2+, Dy3+ Composite Material for 3D Printing.

To break through the simplification of three-dimensional printing (3DP) materials and realize the application of long-persistent phosphors in more fields, polylactic acid doped with Ca2BO3Cl: Eu2+, Dy3+ was prepared in this study. The structure of the mixtures was analyzed and determined by infrared spectroscopy. The luminescence properties of phosphors and the composites were studied by fluorescence spectra and afterglow decay curve measurements. The yellow light of the mixtures could be attributed to the 5d-4f energy level transition of Eu2+. After the excitation of 254 nm ultraviolet lamp, the luminance and duration of the composites could be clearly observed. The mechanical properties of the composite filaments were tested, including maximal force and elasticity modulus. In particular, the influence of humidity on mechanical properties was analyzed in detail. The prepared composite filaments were printed into hollow dodecahedrons and presented in this study. Therefore, the composites had great properties and might be expected to put into practical applications of 3DP technology.

Study on the effect of self-made fracture positioning compression guide device for posterior malleolus fracture surgery: Medical prevention.

To evaluate the effectiveness of a self-designed pressure-guided fracture positioning device, a prospective study was conducted in patients with posterior ankle fractures undergoing surgery using the device. Twenty-seven cases of ankle joint fracture with posterior malleolus fracture were treated by surgery. In the process of fixing posterior malleolus fracture, a self-designed fracture positioning compression guide device was used to fix posterior malleolus bone by anterior and posterior approaches. Postoperative CT images were used to assess the fixation position as well as length of the screw and the compression of the fracture. All patients had healed ankle fractures, and the anterior-posterior screws were fixed in the central area of the posterior malleolus. Posterior malleolus fragment displacement was <2 mm. The screw effectively secured the cortex beyond the length of the posterior malleolus cortex by no more than two threads. The good rate of ankle joint function was 85.16%. Compared to traditional surgical techniques, minimally invasive fixation using the self-designed positioning compression guide device has several advantages, including smaller trauma, faster postoperative recovery, and improved patient satisfaction. The device also provides the surgeon with greater control and precision during the surgical procedure, which can contribute to better surgical outcomes.

Dual Recycling of Depolymerization Catalyst and Biodegradable Polyester that Markedly Outperforms Polyolefins.

Chemically recyclable, circular polymers continue to attract increasing attention, but rendering both catalysts for depolymerization and high-performance polymers recyclable is a more sustainable yet challenging goal. Here we introduce a dual catalyst/polymer recycling system in that recyclable inorganic phosphomolybdic acid catalyzes selective depolymerization of high-ceiling-temperature biodegradable poly(δ-valerolactone) in bulk phase, which, upon reaching suitable molecular weight, exhibits outstanding mechanical performance with a high tensile strength of ≈66.6 MPa, fracture strain of ≈904 %, and toughness of ≈308 MJ m-3 , and thus markedly outperforms commodity polyolefins, recovering its monomer in pure state and quantitative yield at only 100 °C. In sharp contrast, the uncatalyzed depolymerization not only requires a high temperature of >310 °C but is also low yielding and non-selective. Importantly, the recovered monomer can be repolymerized as is to reproduce the same polymer, thereby closing the circular loop, and the recycled catalyst can be reused repeatedly for depolymerization runs without loss of its catalytic activity and efficiency.

Advances in the Synthesis of Chemically Recyclable Polymers.

The development of modern society is closely related to polymer materials. However, the accumulation of polymer materials and their evolution in the environment causes not only serious environmental problems, but also waste of resources. Although physical processing can be used to reuse polymers, the properties of the resulting polymers are significantly degraded. Chemically recyclable polymers, a type of polymer that degrades into monomers, can be an effective solution to the degradation of polymer properties caused by physical recycling of polymers. The ideal chemical recycling of polymers, i. e., quantitative conversion of the polymer to monomers at low energy consumption and repolymerization of the formed monomers into polymers with comparable properties to the original, is an attractive research goal. In recent years, significant progress has been made in the design of recyclable polymers, enabling the regulation of the "polymerization-depolymerization" equilibrium and closed-loop recycling under mild conditions. This review will focus on the following aspects of closed-loop recycling of poly(sulfur) esters, polycarbonates, polyacetals, polyolefins, and poly(disulfide) polymer, illustrate the challenges in this area, and provide an outlook on future directions.

A circular polyester platform based on simple gem-disubstituted valerolactones.

Geminal disubstitution of cyclic monomers is an effective strategy to enhance the chemical recyclability of their polymers, but it is utilized for that purpose alone and often at the expense of performance properties. Here we present synergistic use of gem-α,α-disubstitution of available at-scale, bio-based δ-valerolactones to yield gem-dialkyl-substituted valerolactones ([Formula: see text]), which generate polymers that solve not only the poor chemical recyclability but also the low melting temperature and mechanical performance of the parent poly(δ-valerolactone); the gem-disubstituted polyesters ([Formula: see text]) therefore not only exhibit complete chemical recyclability but also thermal, mechanical and transport properties that rival or exceed those of polyethylene. Through a fundamental structure-property study that reveals intriguing impacts of the alkyl chain length on materials performance of [Formula: see text], this work establishes a simple circular, high-performance polyester platform based on [Formula: see text] and highlights the importance of synergistic utilization of gem-disubstitution for enhancing both chemical recyclability and materials performance of sustainable polyesters.

miR-219a-5p inhibits the pyroptosis in knee osteoarthritis by inactivating the NLRP3 signaling via targeting FBXO3.

PURPOSE: This work was to identify the function and mechanism of miR-219a-5p in regulating knee osteoarthritis (KOA). METHODS: Rat fibroblast-like synoviocytes (FLSs) were isolated to construct KOA cell model by lipopolysaccharide and adenosine triphosphate treatment. miR-219a-5p and FBXO3 expression in FLSs was modulated by transfection. Flow cytometry was executed to research FLSs apoptosis. Caspase-1 and IL-1ß expression in FLSs was researched by immunofluorescence. The binding between miR-219a-5p and FBXO3 was identified by dual luciferase reporter gene assay. KOA rat model and miR-219a-5p up-modulation KOA rat model were constructed. Step size of rats was analyzed. Knee joints of rats were experienced Safranin O-fast green staining to evaluate the knee joint injury. FBXO3, pyroptosis-associated proteins, and IL-1ß and IL-18 expression in FLSs and articular cartilage tissues of rats were assessed by Western blot, qRT-PCR and Enzyme-linked immunosorbent assay. RESULTS: KOA cell model had higher apoptosis percentage, expression of pyroptosis-associated proteins, and IL-1ß and IL-18 level. miR-219a-5p up-modulation decreased the above indicators, whereas miR-219a-5p down-modulation increased the above indicators. FBXO3 expression was directly repressed by miR-219a-5p. Loss of FBXO3 suppressed the above indicators. FBXO3 counteracted the suppression of miR-219a-5p on the above indicators. miR-219a-5p agomir attenuated knee joint injury, increased step size of KOA rats, and reduced FBXO3, pyroptosis-associated proteins and level of IL-1ß and IL-18 in the articular cartilage tissues of KOA rats. CONCLUSION: miR-219a-5p suppressed the pyroptosis in KOA by inactivating the NLRP3 signaling via targeting FBXO3, which might be a promising target for ameliorating KOA in the clinic.

IARS2 regulates proliferation, migration, and angiogenesis of human umbilical vein endothelial cells.

OBJECTIVE: In this study, we aimed at investigating the role of isoleucyl-tRNA synthetase in the growth, migration, and angiogenesis of human umbilical vein endothelial cells and the underlying molecular mechanism. METHODS: To assess the role of isoleucyl-tRNA synthetase, we silenced isoleucyl-tRNA synthetase in human umbilical vein endothelial cells using lentiviral 2 specific short hairpin RNAs (short hairpin RNAs 1 and 2) and examined silencing efficiency using real time quantitative polymerase chain reaction and western blot analyses. Short hairpin RNAs 1-isoleucyl-tRNA synthetase had greater knockdown efficiency, it was used in the entire downstream analysis. Short hairpin RNAs 1- isoleucyl-tRNA synthetase silencing effects on cell proliferation, cell colony generation, cell migration, as well as angiogenesis were assessed using cell counting kit-8, colony development, cell migration, and angiogenesis tube formation assays, respectively. RESULTS: Compared to the control group, anti-isoleucyl-tRNA synthetase short hairpin RNAs significantly silenced isoleucyl-tRNA synthetase expression in human umbilical vein endothelial cells, and suppressed their proliferation, migration, and angiogenic capacity. To characterize the underlying mechanism, western blot analyses showed that isoleucyl-tRNA synthetase knockdown suppressed phosphorylation of extracellular-regulated kinase ½ and protein-serine- threonine kinase, as well as expression of vascular endothelial growth factor, GSK-3ß, and ß-catenin. CONCLUSIONS: We have shown, for the first time, the critical role of isoleucyl-tRNA synthetase in human umbilical vein endothelial cells. Our data show that isoleucyl-tRNA synthetase knockdown suppresses human umbilical vein endothelial cell proliferation, migration, and angiogenesis. We have also shown that isoleucyl-tRNA synthetase knockdown suppresses phosphorylation of extracellular-regulated kinase ½ and protein-serine- threonine kinase, as well as expression of vascular endothelial growth factor, GSK-3ß, and ß-catenin. Together, these data highlight isoleucyl-tRNA synthetase as a potential antitumor anti-angiogenic target.

IARS2 regulates proliferation, migration, and angiogenesis of human umbilical vein endothelial cells

SUMMARY OBJECTIVE: In this study, we aimed at investigating the role of isoleucyl-tRNA synthetase in the growth, migration, and angiogenesis of human umbilical vein endothelial cells and the underlying molecular mechanism. METHODS: To assess the role of isoleucyl-tRNA synthetase, we silenced isoleucyl-tRNA synthetase in human umbilical vein endothelial cells using lentiviral 2 specific short hairpin RNAs (short hairpin RNAs 1 and 2) and examined silencing efficiency using real time quantitative polymerase chain reaction and western blot analyses. Short hairpin RNAs 1-isoleucyl-tRNA synthetase had greater knockdown efficiency, it was used in the entire downstream analysis. Short hairpin RNAs 1- isoleucyl-tRNA synthetase silencing effects on cell proliferation, cell colony generation, cell migration, as well as angiogenesis were assessed using cell counting kit-8, colony development, cell migration, and angiogenesis tube formation assays, respectively. RESULTS: Compared to the control group, anti-isoleucyl-tRNA synthetase short hairpin RNAs significantly silenced isoleucyl-tRNA synthetase expression in human umbilical vein endothelial cells, and suppressed their proliferation, migration, and angiogenic capacity. To characterize the underlying mechanism, western blot analyses showed that isoleucyl-tRNA synthetase knockdown suppressed phosphorylation of extracellular-regulated kinase ½ and protein-serine- threonine kinase, as well as expression of vascular endothelial growth factor, GSK-3β, and β-catenin. CONCLUSIONS: We have shown, for the first time, the critical role of isoleucyl-tRNA synthetase in human umbilical vein endothelial cells. Our data show that isoleucyl-tRNA synthetase knockdown suppresses human umbilical vein endothelial cell proliferation, migration, and angiogenesis. We have also shown that isoleucyl-tRNA synthetase knockdown suppresses phosphorylation of extracellular-regulated kinase ½ and protein-serine- threonine kinase, as well as expression of vascular endothelial growth factor, GSK-3β, and β-catenin. Together, these data highlight isoleucyl-tRNA synthetase as a potential antitumor anti-angiogenic target.

Bioinformatics analysis of miRNA and mRNA expression profiles to reveal the key miRNAs and genes in osteoarthritis.

BACKGROUND: Osteoarthritis (OA) is a chronic degenerative joint disease and the most frequent type of arthritis. This study aimed to identify the key miRNAs and genes associated with OA progression. METHODS: The GSE105027 (microRNA [miRNA/miR] expression profile; 12 OA samples and 12 normal samples) and GSE48556 (messenger RNA [mRNA] expression profile; 106 OA samples and 33 normal samples) datasets were selected from the Gene Expression Omnibus database. Differentially expressed genes (DEGs) and miRNAs (DEMs) were analyzed using the limma and ROCR packages in R, respectively. The target genes that negatively correlated with the DEMs were predicted, followed by functional enrichment analysis and construction of the miRNA-gene and miRNA-transcription factor (TF)-gene regulatory networks. Additionally, key miRNAs and genes were screened, and their expression levels were verified by real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR). RESULTS: A total of 1696 DEGs (739 upregulated and 957 downregulated) and 108 DEMs (56 upregulated and 52 downregulated) were identified in the OA samples. Furthermore, 56 target genes that negatively correlated with the DEMs were predicted and found to be enriched in three functional terms (e.g., positive regulation of intracellular protein transport) and three pathways (e.g., human cytomegalovirus infection). In addition, three key miRNAs (miR-98-5p, miR-7-5p, and miR-182-5p) and six key genes (murine double minute 2, MDM2; glycogen synthase kinase 3-beta, GSK3B; transmembrane P24-trafficking protein 10, TMED10; DDB1 and CUL4-associated factor 12, DCAF12; caspase 3, CASP3; and ring finger protein 44, RNF44) were screened, among which the miR-7-5p → TMED10/DCAF12, miR-98-5p → CASP3/RNF44, and miR-182-5p → GSK3B pairs were observed in the regulatory network. Moreover, the expression levels of TMED10, miR-7-5p, CASP3, miR-98-5p, GSK3B, and miR-182-5p showed a negative correlation with qRT-PCR verification. CONCLUSION: MiR-98-5p, miR-7-5p, miR-182-5p, MDM2, GSK3B, TMED10, DCAF12, CASP3, and RNF44 may play critical roles in OA progression.

Perfectly alternating copolymerization of CO2 and epichlorohydrin using cobalt(III)-based catalyst systems.

Selective transformations of carbon dioxide and epoxides into biodegradable polycarbonates by the alternating copolymerization of the two monomers represent some of the most well-studied and innovative technologies for potential large-scale utilization of carbon dioxide in chemical synthesis. For the most part, previous studies of these processes have focused on the use of aliphatic terminal epoxides or cyclohexene oxide derivatives, with only rare reports concerning the synthesis of CO(2) copolymers from epoxides containing electron-withdrawing groups such as styrene oxide. Herein we report the production of the CO(2) copolymer with more than 99% carbonate linkages from the coupling of CO(2) with epichlorohydrin, employing binary and bifunctional (salen)cobalt(III)-based catalyst systems. Comparative kinetic studies were performed via in situ infrared measurements as a function of temperature to assess the activation barriers for the production of cyclic carbonate versus copolymer involving two electronically different epoxides: epichlorohydrin and propylene oxide. The relative small activation energy difference between copolymer versus cyclic carbonate formation for the epichlorohydrin/CO(2) process (45.4 kJ/mol) accounts in part for the selective synthesis of copolymer to be more difficult in comparison with the propylene oxide/CO(2) case (53.5 kJ/mol). Direct observation of the propagating polymer-chain species from the binary (salen)CoX/MTBD (X = 2,4-dinitrophenoxide and MTBD = 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene) catalyst system by means of electrospray ionization mass spectrometry confirmed the perfectly alternating nature of the copolymerization process. This observation in combination with control experiments suggests possible intermediates involving MTBD in the CO(2)/epichlorohydrin copolymerization process.