The mycorrhiza-specific ammonium transporter ZmAMT3;1 mediates mycorrhiza-dependent nitrogen uptake in maize roots.

Most plant species can form symbioses with arbuscular mycorrhizal fungi (AMFs), which may enhance the host plant's acquisition of soil nutrients. In contrast to phosphorus nutrition, the molecular mechanism of mycorrhizal nitrogen (N) uptake remains largely unknown, and its physiological relevance is unclear. Here, we identified a gene encoding an AMF-inducible ammonium transporter, ZmAMT3;1, in maize (Zea mays) roots. ZmAMT3;1 was specifically expressed in arbuscule-containing cortical cells and the encoded protein was localized at the peri-arbuscular membrane. Functional analysis in yeast and Xenopus oocytes indicated that ZmAMT3;1 mediated high-affinity ammonium transport, with the substrate NH4+ being accessed, but likely translocating uncharged NH3. Phosphorylation of ZmAMT3;1 at the C-terminus suppressed transport activity. Using ZmAMT3;1-RNAi transgenic maize lines grown in compartmented pot experiments, we demonstrated that substantial quantities of N were transferred from AMF to plants, and 68%-74% of this capacity was conferred by ZmAMT3;1. Under field conditions, the ZmAMT3;1-dependent mycorrhizal N pathway contributed >30% of postsilking N uptake. Furthermore, AMFs downregulated ZmAMT1;1a and ZmAMT1;3 protein abundance and transport activities expressed in the root epidermis, suggesting a trade-off between mycorrhizal and direct root N-uptake pathways. Taken together, our results provide a comprehensive understanding of mycorrhiza-dependent N uptake in maize and present a promising approach to improve N-acquisition efficiency via plant-microbe interactions.

Programmable Water Sorption through Linker Installation into a Zirconium Metal-Organic Framework.

Hydrolytically stable materials exhibiting a wide range of programmable water sorption behaviors are crucial for on-demand water sorption systems. While notable advancements in employing metal-organic frameworks (MOFs) as promising water adsorbents have been made, developing a robust yet easily tailorable MOF scaffold for specific operational conditions remains a challenge. To address this demand, we employed a topology-guided linker installation strategy using NU-600, which is a zirconium-based MOF (Zr-MOF) that contains three vacant crystallographically defined coordination sites. Through a judicious selection of three N-heterocyclic auxiliary linkers of specific lengths, we installed them into designated sites, giving rise to six new MOFs bearing different combinations of linkers in predetermined positions. The resulting MOFs, denoted as NU-606 to NU-611, demonstrate enhanced structural stability against capillary force-driven channel collapse during water desorption due to the increased connectivity of the Zr6 clusters in the resulting MOFs. Furthermore, incorporating these auxiliary linkers with various hydrophilic N sites enables the systematic modulation of the pore-filling pressure from about 55% relative humidity (RH) for the parent NU-600 down to below 40% RH. This topology-driven linker installation strategy offers precise control of water sorption properties for MOFs, highlighting a facile route to design MOF adsorbents for use in water sorption applications.

Integrated analysis of DNA methylome and transcriptome revealing epigenetic regulation of CRIR1-promoted cold tolerance.

BACKGROUND: DNA methylation contributes to the epigenetic regulation of nuclear gene expression, and is associated with plant growth, development, and stress responses. Compelling evidence has emerged that long non-coding RNA (lncRNA) regulates DNA methylation. Previous genetic and physiological evidence indicates that lncRNA-CRIR1 plays a positive role in the responses of cassava plants to cold stress. However, it is unclear whether global DNA methylation changes with CRIR1-promoted cold tolerance. RESULTS: In this study, a comprehensive comparative analysis of DNA methylation and transcriptome profiles was performed to reveal the gene expression and epigenetic dynamics after CRIR1 overexpression. Compared with the wild-type plants, CRIR1-overexpressing plants present gained DNA methylation in over 37,000 genomic regions and lost DNA methylation in about 16,000 genomic regions, indicating a global decrease in DNA methylation after CRIR1 overexpression. Declining DNA methylation is not correlated with decreased/increased expression of the DNA methylase/demethylase genes, but is associated with increased transcripts of a few transcription factors, chlorophyll metabolism and photosynthesis-related genes, which could contribute to the CRIR1-promoted cold tolerance. CONCLUSIONS: In summary, a first set of transcriptome and epigenome data was integrated in this study to reveal the gene expression and epigenetic dynamics after CRIR1 overexpression, with the identification of several TFs, chlorophyll metabolism and photosynthesis-related genes that may be involved in CRIR1-promoted cold tolerance. Therefore, our study has provided valuable data for the systematic study of molecular insights for plant cold stress response.

Anchoring Ultrafine ß-Mo2C Clusters Inside Porous Co-NC Using MOFs for Electric-Powered Coproduction of Valuable Chemicals.

Electroredox of organics provides a promising and green approach to producing value-added chemicals. However, it remains a grand challenge to achieve high selectivity of desired products simultaneously at two electrodes, especially for non-isoelectronic transfer reactions. Here a porous heterostructure of Mo2C@Co-NC is successfully fabricated, where subnanometre ß-Mo2C clusters (<1 nm, ≈10 wt%) are confined inside porous Co, N-doped carbon using metalorganic frameworks. It is found that Co species not only promote the formation of ß-Mo2C but also can prevent it from oxidation by constructing the heterojunctions. As noted, the heterostructure achieves >96% yield and 92% Faradaic efficiency (FE) for aldehydes in anodic alcohol oxidation, as well as >99.9% yield and 96% FE for amines in cathodal nitrocompounds reduction in 1.0 M KOH. Precise control of the reaction kinetics of two half-reactions by the electronic interaction between ß-Mo2C and Co is a crucial adjective. Density functional theory (DFT) gives in-depth mechanistic insight into the high aldehyde selectivity. The work guides authors to reveal the electrooxidation nature of Mo2C at a subnanometer level. It is anticipated that the strategy will provide new insights into the design of highly effective bifunctional electrocatalysts for the coproduction of more complex fine chemicals.

Highly Durable Silicone-Based Elastomers Achieved Through the Synergy of Bi-Incompatible Soft Segments and Multi-Scale Hydrogen Bonds.

Developing a silicone elastomer with high strength, exceptional toughness, good crack tolerance, healability, and recyclability, poses significant challenges due to the inherent trade-offs between these properties. Herein, the design of silicone-based elastomers with a nanoscopic microphase separation structure and comprehensive mechanical properties is achieved by combining bi-incompatible soft segments and multi-scale hydrogen bonds. The formation of multi-scale hydrogen bonds involving urethane, urea, and 2-ureido-4[1H]-pyrimidinone (UPy) facilitates efficient reversible crosslinking of the synthesized polymer containing thermodynamically incompatible poly(dimethylsiloxane) (PDMS) and poly(propylene glycol) (PPG). The dynamic dissociation and recombination of hydrogen bonds, coupled with the forced compatibility and spontaneous separation of bi-incompatible soft segments, can effectively dissipate energy, particularly in the crack region during the stretching process. The obtained silicone-based elastomer exhibits a high break strength of 8.0 MPa, good elongation at break of 1910%, ultrahigh toughness of 67.8 MJ m-3, and unprecedented fracture energy of 31.8 kJ m-2 while maintaining their thermal stability, hydrophobicity, healability, and recyclability. This resilient and long-lasting silicone-based elastomer exhibits significant potential for use in flexible electronic devices.

Development of Group IV Metal Complexes Bearing Thioether-Amido Ligands with Enhanced High-Temperature Catalytic Performance toward Olefin Copolymerization.

The development of homogeneous metal catalysts with both high activity and exceptional thermal stability is crucial for the efficient synthesis of polyolefin elastomers (POEs) through solution-phase olefin polymerization. In this study, a series of Hf (Hf1-Hf5), Zr (Zr1), and Ti (Ti1) complexes featuring thioether-amido ligands were synthesized and carefully characterized using advanced techniques such as 1H and 13C NMR spectroscopy as well as single-crystal X-ray diffraction analysis for Hf4 and Hf5. The results revealed that the catalytic activity and 1-octene incorporation efficiency of these metal complexes followed the trend Hf > Zr > Ti, underscoring the significant impact of the metal center on catalytic performance. Furthermore, the choice of ligands was found to play a critical role in dictating the catalytic properties, with ligands bearing less steric hindrance on the sulfur atom proving to be more favorable for copolymerization reactions. Notably, the Hf complex Hf1, featuring a methyl group on the sulfur atom, displayed exceptional catalytic activity as high as 21,060 kg(polymer)·mol-1(Hf)·h-1 toward ethylene/1-octene copolymerization at 120 °C and produced POE with a high molecular weight (Mw = 6.3 × 104 g·mol-1), relatively narrow distribution (D = 2.4), and high incorporation of 1-octene (34.1 mol %). This study demonstrates the potential of tailored ligand design in developing efficient metal catalysts for the production of high-value-added POEs.

Zirconium and Hafnium Complexes Bearing Tridentate ONN-Ligands: Extremely High Activity toward Ethylene (Co)Polymerization.

The pursuit of high-performance catalysts in the realm of polyolefins is a constant goal. In this study, a range of zirconium (1-ZrCl3, 2-ZrCl3, 3-ZrCl4, 12-Zr) and hafnium (1-HfCl3, 12-Hf) complexes featuring phenoxy-imine-amine ONN-ligands (2,6-R2-C6H3-NH-C6H4-N═CH-C6H2-3,5-tBu2-OH; 1-L: R = H; 2-L: R = F; 3-L: R = iPr) were synthesized and characterized using NMR spectroscopy, as well as single-crystal X-ray diffraction for 2-ZrCl3, 3-ZrCl4, and 12-Zr. These Zr and Hf complexes exhibited remarkable efficiency for ethylene homopolymerization and copolymerization with 1-octene when paired with MAO as the cocatalyst. Notably, the Zr complexes outperformed the Hf complexes with the same ligand, underscoring the substantial impact of the metal center on catalytic performance. The substituents and coordination modes of the ligands also exerted significant influence on the catalytic behavior, affecting both the activity and properties of the resulting polymers. Particularly noteworthy was the exceptional activity of 1-ZrCl3, achieving activity as high as 6.30 × 108 g(PE)·mol-1(Zr)·h-1 for ethylene homopolymerization and generating bi- or multimodal distribution polyethylene. The activation of 1-ZrCl3 by 5 or 20 equiv of d-MAO afforded a dinuclear Zr complex bridged by two chlorides (µ-Cl2-(1-ZrCl2)2), which was analyzed and confirmed by in situ 1H NMR spectroscopy and single-crystal X-ray diffraction.

Synthesis and structural optimization of oncolytic peptide LTX-315.

Oncolytic peptides represented potential novel candidates for anticancer treatments especially drug-resistant cancer cell lines. One of the most promising and extensively studied is LTX-315, which is considered as the first in class oncolytic peptide and has entered phase I/II clinical trials. Nevertheless, the shortcomings including poor proteolytic stability, moderate anticancer durability and high synthesis costs may hinder the widespread clinical applications of LTX-315. In order to reduce the synthesis costs, as well as develop derivatives possessing both high protease-stability and durable anticancer efficiency, twenty LTX-315-based derived-peptides were designed and efficiently synthesized. Especially, through solid-phase S-alkylation, as well as the optimized peptide cleavage condition, the derived peptides could be prepared with drastically reduced synthesis cost. The in vitro anticancer efficiency, serum stability, anticancer durability, anti-migration activity, and hemolysis effect were systematically investigated. It was found that derived peptide MS-13 exhibited comparable anticancer efficiency and durability to those of LTX-315. Strikingly, the D-type peptide MS-20, which is the enantiomer of MS-13, was demonstrated to possess significantly high proteolytic stability and sustained anticancer durability. In general, the cost-effective synthesis and stability-guided structural optimizations were conducted on LTX-315, affording the highly hydrolysis resistant MS-20 which possessed durable anticancer activity. Meanwhile, this study also provided a reliable reference for the future optimization of anticancer peptides through the solid-phase S-alkylation and L-type to D-type amino acid substitutions.

The association between the triglyceride-glucose index and in-stent restenosis in patients undergoing percutaneous coronary intervention: a systematic review and meta-analysis.

BACKGROUND: Insulin resistance (IR) can lead to cellular metabolic disorders, activation of oxidative stress, and endothelial dysfunction, contributing to in-stent restenosis (ISR). The triglyceride-glucose index (TyG index), a new indicator reflecting IR, is extensively researched in the cardiovascular field. This study, through a meta-analysis, aimed to utilize a larger combined sample size and thereby enhance the overall test efficacy to explore the TyG index-ISR relationship. METHODS: A thorough search was conducted in the PubMed, EMBASE, Web of Science, and Cochrane Library databases to find original papers and their references published between 1990 and January 2024. This search included both prospective and retrospective studies detailing the correlation between the TyG index and ISR in individuals with coronary heart disease (CHD). OUTCOMES: The five included articles comprised 3,912 participants, and the odds ratio (OR) extracted from each study was combined using the Inverse Variance method. Results showed that, in the context of CHD patients, each incremental unit in the TyG index, when treated as a continuous variable, corresponded to a 42% elevation in ISR risk (95% CI 1.26-1.59, I²=13%, p < 0.005). When analyzing the TyG index categorically, the results revealed a higher ISR risk in the highest TyG index group compared to the lowest group (OR: 1.69, 95% CI 1.32-2.17, I²=0). Additionally, in patients with chronic coronary syndrome (CCS), each unit increase in the TyG index, the risk of ISR in patients increased by 37% (95% CI 1.19-1.57, I²=0%, p < 0.005). This correlation was also observable in acute coronary syndrome (ACS) patients (OR:1.48, 95% CI 1.19-1.85, I²=0, p < 0.005). CONCLUSIONS: The TyG index, an economical and precise surrogate for IR, is significantly linked with ISR. Furthermore, this correlation is unaffected by the type of coronary heart disease.

d-type peptides based fluorescent probes for "turn on" sensing of heparin.

Developing "turn on" fluorescent probes was desirable for the detection of the effective anticoagulant agent heparin in clinical applications. Through combining the aggregation induced emission (AIE) fluorogen tetraphenylethene (TPE) and heparin specific binding peptide AG73, the promising "turn on" fluorescent probe TPE-1 has been developed. Nevertheless, although TPE-1 could achieve the sensitive and selective detection of heparin, the low proteolytic stability and undesirable poor solubility may limit its widespread applications. In this study, seven TPE-1 derived fluorescent probes were rationally designed, efficiently synthesized and evaluated. The stability and water solubility were systematically estimated. Especially, to achieve real-time monitoring of proteolytic stability, the novel Abz/Dnp-based "turn on" probes that employ the internally quenched fluorescent (IQF) mechanism were designed and synthesized. Moreover, the detection ability of synthetic fluorescent probes for heparin were systematically evaluated. Importantly, the performance of d-type peptide fluorescent probe XH-6 indicated that d-type amino acid substitutions could significantly improve the proteolytic stability without compromising its ability of heparin sensing, and attaching solubilizing tag 2-(2-aminoethoxy) ethoxy) acid (AEEA) could greatly enhance the solubility. Collectively, this study not only established practical strategies to improve both the water solubility and proteolytic stability of "turn on" fluorescent probes for heparin sensing, but also provided valuable references for the subsequent development of enzymatic hydrolysis-resistant d-type peptides based fluorescent probes.

Bafi A1 inhibits nano-copper oxide-induced mitochondrial damage by reducing the release of copper from lysosomes.

This study demonstrated that both copper oxide nanoparticles (CuO-NPs) and copper nanoparticles (Cu-NPs) can cause swelling, inflammation, and cause damage to the mitochondria of alveolar type II epithelial cells in mice. Cellular examinations indicated that both CuO-NPs and Cu-NPs can reduce cell viability and harm the mitochondria of human bronchial epithelial cells, particularly Beas-2B cells. However, it is clear that CuO-NPs exhibit a more pronounced detrimental effect compared with Cu-NPs. Using bafilomycin A1 (Bafi A1), an inhibitor of lysosomal acidification, was found to enhance cell viability and alleviate mitochondrial damage caused by CuO-NPs. Additionally, Bafi A1 also reduces the accumulation of dihydrolipoamide S-acetyltransferase (DLAT), a marker for mitochondrial protein toxicity, induced by CuO-NPs. This observation suggests that the toxicity of CuO-NPs depends on the distribution of copper particles within cells, a process facilitated by the acidic environment of lysosomes. The release of copper ions is thought to be triggered by the acidic conditions within lysosomes, which aligns with the lysosomal Trojan horse mechanism. However, this association does not seem to be evident with Cu-NPs.

Phase-locked µPIV analysis of flow dynamics in a simulated root canal with different laser-activated irrigations.

PURPOSE: To measure the dynamic characteristics of the flow field in a complex root canal model activated by two laser-activated irrigation (LAI) modalities at different activation energy outputs: photon-induced photoacoustic streaming (PIPS) and microshort pulse (MSP). METHODS: A phase-locked micro-scale Particle Image Velocimetry (µPIV) system was employed to characterise the temporal variations of LAI-induced velocity fields in the root canal following a single laser pulse. The wall shear stress (WSS) in the lateral root canal was subsequently estimated from the phase-averaged velocity fields. RESULTS: Both PIPS and MSP were able to generate the 'breath mode' of the irrigant current under all tested conditions. The transient irrigation flush in the root canal peaked at speeds close to 6 m/s. However, this intense flushing effect persisted for only about 2000 µs (or 3% of a single laser-pulse activation cycle). For MSP, the maximum WSS magnitude was approximately 3.08 Pa at an activation energy of E = 20 mJ/pulse, rising to 9.01 Pa at E = 50 mJ/pulse. In comparison, PIPS elevated the WSS to 10.63 Pa at E = 20 mJ/pulse. CONCLUSION: Elevating the activation energy can boost the peak flushing velocity and the maximum WSS, thereby enhancing irrigation efficiency. Given the same activation energy, PIPS outperforms MSP. Additionally, increasing the activation frequency may be an effective strategy to improve irrigation performance further.

Creating Remarkably Moisture- and Air-Stable Macromolecular Lewis Acid by Integrating Borane within the Polymer Chain: A Highly Active Catalyst for Homo(co)polymerization of Epoxides.

Borane-based Lewis acids (LA) play an indispensable role in the Lewis pair (LP) mediated polymerization. However, most borane-based LPs are moisture- and air-sensitive. Therefore, development of moisture and air-stable borane-based LP is highly desirable. To achieve this goal, the concept of "aggregation induced enlargement effects" by chemically linking multiple borane within a nanoscopic confinement was conceived to create macromolecular LA. Accordingly, an extremely moisture and air stable macromolecular borane, namely, PVP-1B featuring poly(4-vinylphenol) backbone, was constructed. The concentration of borane active site is greatly higher than average concentration due to local confinement. Therefore, an enhanced activity was observed. Moreover, the local LA aggregation effects allow its tolerance to air and large amount of chain transfer agent. Consequently, PVP-1B showed remarkable efficiency for propylene oxide (PO) polymerization at 25 °C (TOF=27900 h-1 ). Furthermore, it enables generation of well-defined telechelic poly (CHO-alt-CO2 ) diol (0.6-15.3 kg/mol) with narrow Ds via copolymerizing cyclohexene oxide and CO2 at 80 °C. This work indicates unifying multiple borane within a polymer in a macromolecular level shows superior catalytic performance than constructing binary, bi(multi)functional systems in a molecular level. This paves a new way to make functional polyethers.

Building Ultrastrong, Tough and Biodegradable Thermoplastic Elastomers from Multiblock Copolyesters via a "Reserve-Release" Crystallization Strategy.

Simultaneously attaining high strength and toughness has been a significant challenge in designing thermoplastic elastomers, especially biodegradable ones. In this context, we present a class of biodegradable elastomers based on multiblock copolyesters that afford extraordinary strength, toughness, and low-strain resilience despite expedient chemical synthesis and sample processing. With the incorporation of the semi-crystalline soft block and the judicious selection of block periodicity, the thermoplastic materials feature low quiescent crystallinity ("reserve") albeit with vast potential for strain-induced crystallization ("release"), resulting in their significantly enhanced ultimate strength and energy-dissipating capabilities. Moreover, a breadth of mechanical responses of the materials - from reinforced elastomers to shape-memory materials to toughened thermoplastics - can be achieved by orthogonal variation of segment lengths and ratios. This work and the "reserve-release" crystallization strategy herein highlight the double crystalline multiblock chain architecture as a potential avenue towards reconciling the strength-toughness trade-off in thermoplastic elastomers and can possibly be extended to other biodegradable building blocks to deliver functional materials with diverse mechanical performances.

Chemoselective Ring-opening Polymerization of α-Methylene-δ-valerolactone Catalyzed by a Simple Organoaluminum Complex to Prepare Closed-loop Recyclable Functional Polyester.

α-Methylene-δ-valerolactone (MVL) as a bio-renewable bifunctional monomer has shown great promise to prepare closed-loop recyclable polyester with pendent functionalizable double bond. However, the chemoselective ring-opening polymerization (ROP) of MVL still faces challenges including low polymerization temperature, expensive catalyst as well as high catalyst loading. In this contribution, we present the chemoselective and controlled ROP of MVL using a simple organoaluminum complex [MeAl(BHT)2] (BHT = 2,6-di-tert-butyl-4-methylphenoxy), which can be easily prepared from commercially available trimethylaluminum and 2,6-di-tert-butyl-4-methylphenol without purification. MeAl(BHT)2 exhibits much higher catalytic activity (TOF = 668 h-1) than that of MeAl[Salen] (TOF = 89 h-1), a commonly used organoaluminum catalyst. The high chemoselectivity and activity of MeAl(BHT)2 is proposed to originate from the cooperative activation of propagating chain-ends and monomers via the "coordination-insertion" mechanism. Remarkably, high-molecular-weight P(MVL)ROP can be prepared in bulk using MeAl(BHT)2, which is not accessible by the previous catalysts. This study may advance the development of closed-loop recyclable polymers considering the easy preparation, low cost and good catalytic performance of MeAl(BHT)2.

Bulky Phosphazenium Salt Controlling Chemoselective Terpolymerization of Epoxide, Anhydride and CO2: From Well-Defined Block to Truly Random Copolymers.

Copolymers with precise compositions and controlled sequences are great appealing for high-performance polymeric materials, but their synthesis is very challenging. In this study, tetrakis[tris(dimethylamino)phosphoranylidenamino] phosphonium chloride (P5Cl) and triethylboron (TEB) were chosen as the binary catalyst to synthesize both well-defined block and truly random poly(ester-carbonate) copolymers via the one-pot/one-step terpolymerization of epoxide/anhydride/CO2 under metal-free conditions. The bulky nature of phosphazenium cation not only led to loose cation-anion pairs and enhanced the reactivity, but also provided the chain-end an appropriate protection and improved the controllability. In particular, P5Cl/TEB with a molar ratio of 1/0.5 showed an extraordinary chemoselectivity for ring-opening alternating copolymerization (ROAC) of cyclohexene oxide (CHO) and phthalic anhydride (PA) first and then ROAC of CHO/CO2. Thus, well-defined block polyester-polycarbonate copolymers were synthesized by CHO/PA/CO2 terpolymerization. The chemoselectivity was easily tuned and the ROAC of CHO/PA and ROAC of CHO/CO2 occurred simultaneously with P5Cl/TEB=1/2, producing truly random poly(ester-carbonate) copolymers from CHO/PA/CO2. In addition, this P5Cl/TEB catalyst and the strategy to regulate its chemoselectivity are versatile for various anhydrides, epoxides and initiators. Thus, poly(ester-carbonate) copolymers with varying sequences, compositions, and topologies are successfully synthesized, making it possible to compare their properties and to expand their applications.

Dinuclear Group 4 Metal Complexes Bearing Anthracene-Bridged Bifunctional Amido-Ether Ligands: Remarkable Metal Effect and Cooperativity toward Ethylene/1-Octene Copolymerization.

Two types of bifunctional amido-ether ligands (syn-L and anti-L) with the rigid anthracene skeleton were designed to support dinuclear group 4 metal complexes. All organic ligands and organometallic complexes (syn-M2 and anti-M2; M = Hf, Zr, and Ti) were fully characterized by 1H and 13C NMR spectroscopies and elemental analyses. The anti-Hf2 complex showed two confirmations at room temperature with C2-symmetry or S2-symmetry that can inter-exchange, as indicated by VT NMR, while only a C2-symmetric isomer was observed for syn-Hf2 complex at room temperature. However, for Zr and Ti analogues, both syn and anti complexes exhibited only one conformation at room temperature. The molecular structures of complexes syn-Hf2, anti-Hf2, and syn-Ti2 in the solid state were further determined by single-crystal X-ray diffraction, revealing the distances between two metal centers in syn-M2 from 7.138 Å (syn-Ti2) to 7.321 Å (syn-Hf2) but a much farther separation in anti-M2 (8.807 Å in C2-symmetric anti-Hf2). The mononuclear complex (2-CH3O-C6H4-N-C14H9)Zr(NMe2)3 (mono-Zr1) was also prepared for control experiments. In the presence of alkyl aluminum (AlEt3) as the alkylating agent and trityl borate ([Ph3C][B(C6F5)4]) as the co-catalyst, all metal complexes were tested for copolymerization of ethylene with 1-octene at high temperature (130 °C). The preliminary polymerization results revealed that the activity was highly dependent upon the nature of metal centers, and syn-Zr2 showed the highest activity of 9600 kg(PE)·mol-1 (Zr)·h-1, which was about 17- and 2.2-fold higher than those of syn-Hf2 and syn-Ti2, respectively. Benefitting from both steric proximity and electronical interaction of two metal centers, syn-Zr2 exhibited significant cooperativity in comparison to anti-Zr2 and mono-Zr1, with regard to activity and molecular weight and 1-octene incorporation of resultant copolymers.

Efficient synthesis and anticancer evaluation of spider toxin peptide LVTX-8-based analogues with enhanced stability.

Cytotoxic peptides derived from spider venoms have been considered as promising candidates for anticancer treatment. The novel cell penetrating peptide LVTX-8, which is a 25-residue amphipathic α-helical peptide isolated from spider Lycosa vittata, exhibited potent cytotoxicity and is a potential precursor for further anticancer drug development. Nevertheless, LVTX-8 may be easily degraded by multiple proteases, inducing the proteolytic stability problem and short half-life. In this study, ten LVTX-8-based analogs were rationally designed and the efficient manual synthetic method was established by the DIC/Oxyma based condensation system. The cytotoxicity of synthetic peptides was systematically evaluated against seven cancer cell lines. Seven of the derived peptides exhibited high cytotoxicity towards tested cancer in vitro, which was better than or comparable to that of natural LVTX-8. In particular, both N-acetyl and C-hydrazide modified LVTX-8 (825) and the conjugate methotrexate (MTX)-GFLG-LVTX-8 (827) possessed more durable anticancer efficiency, higher proteolytic stability, as well as lower hemolysis. Finally, we confirmed that LVTX-8 could disrupt the integrity of cell membrane, target the mitochondria and reduce the mitochondrial membrane potential to induce the cell death. Taken together, the structural modifications were conducted on LVTX-8 for the first time and the stability significantly improved derivatives 825 and 827 may provide useful references for the modifications of cytotoxic peptides.

Laser Sensing and Vision Sensing Smart Blind Cane: A Review.

Laser sensing and vision sensing smart canes can improve the convenience of travel for the visually impaired, but for the present, most of the system functions of laser sensing and vision sensing smart canes are still defective. Guide equipment and smart blind canes are introduced and classified first, and the smart blind canes based on vision sensing, laser sensing and laser vision sensing are investigated, respectively, and the research status of laser vision sensing smart blind canes is sorted out. The advantages and disadvantages of various laser vision sensing smart blind canes are summarized, especially the research development of laser vision fusion as the core of new smart canes. The future development prospects of laser vision sensing smart blind cane are overviewed, to boost the development of laser vision sensing smart blind cane, to provide safe and efficient travel guarantee for the visually impaired.

Ring-opening Polymerization of Enantiopure Bicyclic Ether-ester Monomers toward Closed-loop Recyclable and Crystalline Stereoregular Polyesters via Chemical Upcycling of Bioplastic.

Although great successes have been achieved, the preparation of closed-loop recyclable polyesters with high working temperatures still remains as a big challenge. Herein, we present the syntheses of a series of enantiopure bicyclic ether-ester monomers by upcycling of poly(3-hydroxybutyrate) bioplastic. The "living"/controlled ring-opening polymerizations of these enantiopure monomers to produce stereoregular polyesters with controlled molecular weights and well-defined chain ends were achieved. The effects of stereoconfiguration and substituent on polymerization kinetics and thermodynamics as well as the thermal properties of resultant polyesters were investigated. Of note, the stereoregular polyesters are semi-crystalline materials with melting temperatures up to 176 °C, even higher than the commodity polyolefin plastics. These polyesters can be depolymerized back to recover pristine monomers, thus successfully establishing a closed-loop life cycle.