Phospholipid Bilayer Inspired Sandwich Structural Nanofibrous Membrane for Atmospheric Water Harvesting and Selective Release.

Atmospheric water harvesting (AWH) has been broadly exploited to meet the challenge of water shortage. Despite the significant achievements of AWH, the leakage of hydroscopic salt during the AWH process hinders its practical applications. Herein, inspired by the unique selective permeability of the phospholipid bilayer, a sandwich structural (hydrophobic-hydrophilic-hydrophobic) polyacrylonitrile nanofibrous membrane (San-PAN) was fabricated for AWH. The hydrophilic inner layer loaded with LiCl could capture water from the air. The hydrophobic microchannels in the outer layer could selectively allow the free transmission of gaseous water molecules but confine the hydroscopic salt solution in the hydrophilic layer, achieving continuous and recyclable water sorption/desorption. As demonstrated, the as-prepared AWH devices presented high-efficient adsorption kinetics from 1.66 to 4.08 g g-1 at 30% to 90% relative humidity. Thus, this work strengthens the understanding of the water transmission process along microchannels and provides insight into the practical applications of AWH.

Ultrafast Super-Resolution Imaging Exploiting Spontaneous Blinking of Static Excimer Aggregates.

Single-molecule localization methods have been popularly exploited to obtain super-resolved images of biological structures. However, the low blinking frequency of randomly switching emission states of individual fluorophores greatly limits the imaging speed of single-molecule localization microscopy (SMLM). Here we present an ultrafast SMLM technique exploiting spontaneous fluorescence blinking of cyanine dye aggregates confined to DNA framework nanostructures. The DNA template guides the formation of static excimer aggregates as a "light-harvesting nanoantenna", whereas intermolecular excitation energy transfer (EET) between static excimers causes collective ultrafast fluorescence blinking of fluorophore aggregates. This DNA framework-based strategy enables the imaging of DNA nanostructures with 12.5-fold improvement in speed compared to conventional SMLM. Further, we demonstrate the use of this strategy to track the movement of super-resolved DNA nanostructures for over 20 min in a microfluidic system. Thus, this ultrafast SMLM holds great potential for revealing the dynamic processes of biomacromolecules in living cells.

Tricoordinated Single-Atom Cobalt in Zeolite Boosting Propane Dehydrogenation.

Propane dehydrogenation (PDH) reaction has emerged as one of the most promising propylene production routes due to its high selectivity for propylene and good economic benefits. However, the commercial PDH processes usually rely on expensive platinum-based and poisonous chromium oxide based catalysts. The exploration of cost-effective and ecofriendly PDH catalysts with excellent catalytic activity, propylene selectivity, and stability is of great significance yet remains challenging. Here, we discovered a new active center, i.e., an unsaturated tricoordinated cobalt unit (≡Si-O)CoO(O-Mo) in a molybdenum-doped silicalite-1 zeolite, which afforded an unprecedentedly high propylene formation rate of 22.6 molC3H6 gCo-1 h-1 and apparent rate coefficient of 130 molC3H6 gCo-1 h-1 bar-1 with >99% of propylene selectivity at 550 °C. Such activity is nearly one magnitude higher than that of previously reported Co-based catalysts in which cobalt atoms are commonly tetracoordinated, and even superior to that of most of Pt-based catalysts under similar operating conditions. Density functional theory calculations combined with the state-of-the-art characterizations unravel the role of the unsaturated tricoordinated Co unit in facilitating the C-H bond-breaking of propane and propylene desorption. The present work opens new opportunities for future large-scale industrial PDH production based on inexpensive non-noble metal catalysts.

Chemoproteomic strategy identifies PfUCHL3 as the target of halofuginone.

The human malaria parasite Plasmodium falciparum (P. falciparum) continues to pose a significant public health challenge, leading to millions of fatalities globally. Halofuginone (HF) has shown a significant anti-P. falciparum effect, suggesting its potential as a therapeutic agent for malaria treatment. In this study, we synthesized a photoaffinity labeling probe of HF to identify its direct target in P. falciparum. Our results reveal that ubiquitin carboxyl-terminal hydrolase 3 (PfUCHL3) acts as a crucial target protein of HF, which modulates parasite growth in the intraerythrocytic cycle. In particular, we discovered that HF potentially forms hydrogen bonds with the Leu10, Glu11, and Arg217 sites of PfUCHL3, thereby inducing an allosteric effect by promoting the embedding of the helix 6' region on the protein surface. Furthermore, HF disrupts the expression of multiple functional proteins mediated by PfUCHL3, specifically those that play crucial roles in amino acid biosynthesis and metabolism in P. falciparum. Taken together, this study highlights PfUCHL3 as a previously undisclosed druggable target of HF, which contributes to the development of novel anti-malarial agents in the future.

Well-defined N3 C1 -anchored Single-Metal-Sites for Oxygen Reduction Reaction.

N-, C-, O-, S-coordinated single-metal-sites (SMSs) have garnered significant attention due to the potential for significantly enhanced catalytic capabilities resulting from charge redistribution. However, significant challenges persist in the precise design of well-defined such SMSs, and the fundamental comprehension has long been impeded in case-by-case reports using carbon materials as investigation targets. In this work, the well-defined molecular catalysts with N3 C1 -anchored SMSs, i.e., N-confused metalloporphyrins (NCPor-Ms), are calculated for their catalytic oxygen reduction activity. Then, NCPor-Ms with corresponding N4 -anchored SMSs (metalloporphyrins, Por-Ms), are synthesized for catalytic activity evaluation. Among all, NCPor-Co reaches the top in established volcano plots. NCPor-Co also shows the highest half-wave potential of 0.83 V vs. RHE, which is much better than that of Por-Co (0.77 V vs. RHE). Electron-rich, low band gap and regulated d-band center contribute to the high activity of NCPor-Co. This study delves into the examination of well-defined asymmetric SMS molecular catalysts, encompassing both theoretical and experimental facets. It serves as a pioneering step towards enhancing the fundamental comprehension and facilitating the development of high-performance asymmetric SMS catalysts.

Highly Dispersed Pd-CeOx Nanoparticles in Zeolite Nanosheets for Efficient CO2-Mediated Hydrogen Storage and Release.

Formic acid (FA) dehydrogenation and CO2 hydrogenation to FA/formate represent promising methodologies for the efficient and clean storage and release of hydrogen, forming a CO2-neutral energy cycle. Here, we report the synthesis of highly dispersed and stable bimetallic Pd-based nanoparticles, immobilized on self-pillared silicalite-1 (SP-S-1) zeolite nanosheets using an incipient wetness co-impregnation technique. Owing to the highly accessible active sites, effective mass transfer, exceptional hydrophilicity, and the synergistic effect of the bimetallic species, the optimized PdCe0.2/SP-S-1 catalyst demonstrated unparalleled catalytic performance in both FA dehydrogenation and CO2 hydrogenation to formate. Remarkably, it achieved a hydrogen generation rate of 5974 molH2 molPd-1 h-1 and a formate production rate of 536 molformate molPd-1 h-1 at 50 °C, surpassing most previously reported heterogeneous catalysts under similar conditions. Density functional theory calculations reveal that the interfacial effect between Pd and cerium oxide clusters substantially reduces the activation barriers for both reactions, thereby increasing the catalytic performance. Our research not only showcases a compelling application of zeolite nanosheet-supported bimetallic nanocatalysts in CO2-mediated hydrogen storage and release but also contributes valuable insights towards the development of safe, efficient, and sustainable hydrogen technologies.

Heteroatoms-Stabilized Single Palladium Atoms on Amorphous Zeolites: Breaking the Tradeoff between Catalytic Activity and Selectivity for Alkyne Semihydrogenation.

As a fundamental industrial catalytic process, the semihydrogenation of alkynes presents a challenge in striking a balance between activity and selectivity due to the issue of over-hydrogenation. Herein, we develop an efficient catalytic system based on single-atom Pd catalysts supported on boron-containing amorphous zeolites (Pd/AZ-B), achieving the tradeoff breaking between the activity and selectivity for the selective hydrogenation of alkynes. Advanced characterizations and theoretical density functional theory calculations confirm that the incorporated B atoms in the Pd/AZ-B can not only alter the geometric and electronic properties of Pd atoms by controlling the electron migration from Pd but also mitigate the interaction between alkene and the catalyst supports. This boosts the exceptional catalytic efficacy in the semihydrogenation of phenylacetylene to styrene under mild conditions (298 K, 2 bar H2), achieving a recorded turnover frequency (TOF) value of 24198 h-1 and demonstrating 95% selectivity to styrene at full conversion of phenylacetylene. By comparison, the heteroatom-free amorphous zeolite-anchored Pd nanoparticles and the commercial Lindlar catalyst have styrene selectivities of 73% and 15%, respectively, under identical reaction conditions. This work establishes a solid foundation for developing highly active and selective hydrogenation catalysts by controllably optimizing their electronic and steric properties.

Regulating Reconstruction-Engineered Active Sites for Accelerated Electrocatalytic Conversion of Urea.

Reconstruction-engineered electrocatalysts with enriched high active Ni species for urea oxidation reaction (UOR) have recently become promising candidates for energy conversion. However, to inhibit the over-oxidation of urea brought by the high valence state of Ni, tremendous efforts are devoted to obtaining low-value products of nitrogen gas to avoid toxic nitrite formation, undesirably causing inefficient utilization of the nitrogen cycle. Herein, we proposed a mediation engineering strategy to significantly boost high-value nitrite formation to help close a loop for the employment of a nitrogen economy. Specifically, platinum-loaded nickel phosphides (Pt-Ni2P) catalysts exhibit a promising nitrite production rate (0.82 mol kWh-1 cm-2), high stability over 66 h of Zn-urea-air battery operation, and 135 h of co-production of nitrite and hydrogen under 200 mA cm-2 in a zero-gap membrane electrode assembly (MEA) system. The in situ spectroscopic characterizations and computational calculations demonstrated that the urea oxidation kinetics is facilitated by enriched dynamic Ni3+ active sites, thus augmenting the "cyanate" UOR pathway. The C-N cleavage was further verified as the rate-determining step for nitrite generation.

Cobalt-Promoted Noble-Metal Catalysts for Efficient Hydrogen Generation from Ammonia Borane Hydrolysis.

Ammonia borane (AB) has been regarded as a promising material for chemical hydrogen storage. However, the development of efficient, cost-effective, and stable catalysts for H2 generation from AB hydrolysis remains a bottleneck for realizing its practical application. Herein, a step-by-step reduction strategy has been developed to synthesize a series of bimetallic species with small sizes and high dispersions onto various metal oxide supports. Superior to other non-noble metal species, the introduction of Co species can remarkably and universally promote the catalytic activity of various noble metals (e.g., Pt, Rh, Ru, and Pd) in AB hydrolysis reactions. The optimized Pt0.1%Co3%/TiO2 catalyst exhibits a superhigh H2 generation rate from AB hydrolysis, showing a turnover frequency (TOF) value of 2250 molH2 molPt-1 min-1 at 298 K. Such a TOF value is about 10 and 15 times higher than that of the monometal Pt/TiO2 and commercial Pt/C catalysts, respectively. The density functional theory (DFT) calculation reveals that the synergy between Pt and CoO species can remarkably promote the chemisorption and dissociation of water molecules, accelerating the H2 evolution from AB hydrolysis. Significantly, the representative Pt0.25%Co3%/TiO2 catalyst exhibits excellent stability, achieving a record-high turnover number of up to 215,236 at room temperature. The excellent catalytic performance, superior stability, and low cost of the designed catalysts create new prospects for their practical application in chemical hydrogen storage.

IL-17A induces valvular endothelial inflammation and aggravates calcific aortic valve disease.

Calcific aortic valve disease (CAVD) is an aging related disease characterized by inflammation and fibrocalcific remodeling. IL-17A is a key cytokine associated with pathophysiology of inflammatory and fibrotic disease. Previous studies showed accumulation of IL-17A-producing T helper lymphocytes in human calcified aortic valves and significantly elevated IL-17RA expression in calcified valves. However, the role of IL-17A signaling in the initiation and development of CAVD is still unclear. In this study, by analyzing public transcriptome databases, we found that IL-17A-IL-17RA signaling is activated in calcified valves. Gene expression analysis revealed significantly increased IL-17A, IL-17RA, and RUNX2 expression in calcified human aortic valves compared to in non-calcified valves, and the expression of IL-17A and IL-17RA were positively correlated with RUNX2 expression. A 5/6 nephrectomy was performed in Apoe-/- (Apoe knockout) mice to establish a CAVD mouse model. IL-17A-neutralizing antibodies significantly reduced valve calcium deposition and decreased expression of RUNX2 in aortic valves. Immunofluorescence staining of human aortic valves and qRT-PCR analysis of primary aortic valve cells revealed abundant expression of IL-17RA in valvular endothelial cells (VECs). RNA sequencing indicated that IL-17A promoted the activation of inflammatory signaling pathways in VECs. Furthermore, qRT-PCR and cytometric bead array analysis confirmed that IL-17A promoted the expression or secretion of inflammatory cytokines IL-6 and IL-1ß, chemokines CXCL2 and CXCL8, and fibrosis-related gene COL16A1. Our findings indicate that elevated IL-17A in CAVD may promote valve inflammation, fibrosis, and calcification by inducing endothelial activation and inflammation. Targeting IL-17A-IL-17RA signaling may be a potential therapeutic strategy for CAVD.

Chiral Polymer Dots Show Unexpected Versatility of Highly Ordered Self-Assembly into Chiroptical Liquid Crystals, Ultra-Thin Films, and Long-Ribbons.

Compared to the organic counterparts, chiral self-assembly of nanomaterials shows persistency to kinetic factors such as solvent environments, and consequently, dynamic modulation of self-assembly and functions remains major challenge. Here, it is shown that alkylated, chiral polymer dots (c-PDs) give highly ordered self-assemblies with amplified chirality adaptive to solvent environments, and one-to-many hierarchical aggregation can be realized. The c-PDs tended to self-assemble into nanohelices with cubic packing in the solid state, which, thanks to the thermo-responsiveness, transformed into thermic liquid crystals upon heating. Cotton effects and circularly polarized luminescence evidenced the chirality transfer from central chirality to supramolecular chirality. At the air-water interface, the c-PDs are self-assembled into monolayers, which further stack into multiple layers with chirality transfer and highly ordered packing. In addition, undergoing a good/poor solvent exchange, the c-PDs afforded ultra-long microribbons up to a length scale of millimeters, which are constituted by the bilayer lamellar stacking. The versatile chiral self-assembly modalities with long-range ordered packing arrays of carbonized c-PDs via solvent strategy are realized. This feature is comparable to the organic species, although the c-PDs have no atomic precise structures. This work would surely expand the applications of quantum dot ordered self-assembly with adaptiveness to kinetic factors.

Embedding Ru Clusters and Single Atoms into Perovskite Oxide Boosts Nitrogen Fixation and Affords Ultrahigh Ammonia Yield Rate.

Ammonia is a key chemical feedstock worldwide. Compared with the well-known Haber-Bosch method, electrocatalytic nitrogen reduction reaction (ENRR) can eventually consume less energy and have less CO2 emission. In this study, a plasma-enhanced chemical vapor deposition method is used to anchor transition metal element onto 2D conductive material. Among all attempts, Ru single-atom and Ru-cluster-embedded perovskite oxide are discovered with promising electrocatalysis performance for ENRR (NH3 yield rate of up to 137.5 ± 5.8 µg h-1  mgcat -1 and Faradaic efficiency of unexpected 56.9 ± 4.1%), reaching the top record of Ru-based catalysts reported so far. In situ experiments and density functional theory calculations confirm that the existence of Ru clusters can regulate the electronic structure of Ru single atoms and decrease the energy barrier of the first hydrogenation step (*NN to *NNH). Anchoring Ru onto various 2D perovskite oxides (LaMO-Ru, MCr, Mn, Co, or Ni) also show boosted ENRR performance. Not only this study provides an unique strategy toward transition-metal-anchored new 2D conductive materials, but also paves the way for fundamental understanding the correlation between cluster-involved single-atom sites and catalytic performance.

Contributions of Support Point Number to Mirror Assembly Thermal Sensitivity Control.

Due to the extreme environmental temperature variations, solutions that enable ultra-low thermal sensitivity in a mirror assembly are crucial for high-performance aerial optical imaging sensors (AOIS). Strategies such as the elimination of the coefficient of thermal expansion (CTE) mismatch and the employment of a flexure connection at the interface cannot be simply duplicated for the application involved, demanding specific design constraints. The contributions of support point number to the surface thermal sensitivity reduction and support stiffness improvement have been studied. A synthetic six-point support system that integrates equally spaced multiple ultra-low radial stiffness mirror flexure units and assembly external interface flexure units has been demonstrated on a 260 mm apertured annular mirror that involves significant CTE mismatch and demanding support stiffness constraint. The surface deformation RMS, due to the 35 °C temperature variation, is 16.7 nm.

MicroRNA-223-3p inhibits vascular calcification and the osteogenic switch of vascular smooth muscle cells.

Vascular calcification is the ectopic deposition of calcium hydroxyapatite minerals in arterial wall, which involves the transdifferentiation of vascular smooth muscle cells (VSMCs) toward an osteogenic phenotype. However, the underlying molecular mechanisms regulating the VSMC osteogenic switch remain incompletely understood. In this study, we examined the roles of microRNAs (miRNAs) in vascular calcification. miRNA-seq transcriptome analysis identified miR-223-3p as a candidate miRNA in calcified mouse aortas. MiR-223-3p knockout aggravated calcification in both medial and atherosclerotic vascular calcification models. Further, RNA-seq transcriptome analysis verified JAK-STAT and PPAR signaling pathways were upregulated in both medial and atherosclerotic calcified aortas. Overlapping genes in these signaling pathways with predicted target genes of miR-223-3p derived from miRNA databases, we identified signal transducer and activator of transcription 3 (STAT3) as a potential target gene of miR-223-3p in vascular calcification. In vitro experiments showed that miR-223-3p blocked interleukin-6 (IL-6)/STAT3 signaling, thereby preventing the osteogenic switch and calcification of VSMCs. In contrast, overexpression of STAT3 diminished the effect of miR-223-3p. Taken together, the results indicate a protective role of miR-223-3p that inhibits both medial and atherosclerotic vascular calcification by regulating IL-6/STAT3 signaling-mediated VSMC transdifferentiation.

Magnesium dicarboxylates promote the prenylation of phenolics that is extended to the total synthesis of icaritin.

The prenylation of phenolic substrates promoted by magnesium dicarboxylates was developed. An investigation of the scope demonstrated that substrates with electron-donating group(s) gave better yields than those with electron-withdrawing group(s). Although the conversions of all substrates were higher in MeCN than in DMF, DMF was still the favorable solvent for polyphenolic substrates since MeCN would cause the generation of cyclized by-products (6) and reduce the yield of 3. The regio-selectivity of ortho- vs. para-prenylation (3'vs.3'') for those para-unoccupied substrates was also solvent dependant. DMF produced mainly ortho-products but with poor conversions. On the other hand, MeCN generated mainly para-products, along with minor ortho-products. Mechanistic study of the prenylation provided evidence for the nucleophilic addition/substitution of the phenolic substrate to the alkyl halide in the presence of the magnesium dicarboxylates. The proto application of this method in the total synthesis of icaritin through the prenylation of 2,4,6-trihydroxyacetophenone, followed by the reaction with benzaldehyde to afford the flavonol, was successful, with a total yield of 33%.

Boosting the Electrocatalytic Conversion of Nitrogen to Ammonia on Metal-Phthalocyanine-Based Two-Dimensional Conjugated Covalent Organic Frameworks.

The electrochemical N2 reduction reaction (NRR) under ambient conditions is attractive in replacing the current Haber-Bosch process toward sustainable ammonia production. Metal-heteroatom-doped carbon-rich materials have emerged as the most promising NRR electrocatalysts. However, simultaneously boosting their NRR activity and selectivity remains a grand challenge, while the principle for precisely tailoring the active sites has been elusive. Herein, we report the first case of crystalline two-dimensional conjugated covalent organic frameworks (2D c-COFs) incorporated with M-N4-C centers as novel, defined, and effective catalysts, achieving simultaneously enhanced activity and selectivity of electrocatalytic NRR to ammonia. Such 2D c-COFs are synthesized based on metal-phthalocyanine (M = Fe, Co, Ni, Mn, Zn, and Cu) and pyrene units bonded by pyrazine linkages. Significantly, the 2D c-COFs with Fe-N4-C center exhibit higher ammonia yield rate (33.6 µg h-1 mgcat-1) and Faradaic efficiency (FE, 31.9%) at -0.1 V vs reversible hydrogen electrode than those with other M-N4-C centers, making them among the best NRR electrocatalysts (yield rate >30 µg h-1 mgcat-1 and FE > 30%). In situ X-ray absorption spectroscopy, Raman spectroelectrochemistry, and theoretical calculations unveil that Fe-N4-C centers act as catalytic sites. They show a unique electronic structure with localized electronic states at Fermi level, allowing for stronger interaction with N2 and thus faster N2 activation and NRR kinetics than other M-N4-C centers. Our work opens the possibility of developing metal-nitrogen-doped carbon-rich 2D c-COFs as superior NRR electrocatalyst and provides an atomic understanding of the NRR process on M-Nx-C based electrocatalysts for designing high-performance NRR catalysts.

Catechol-Coordinated Framework Film-based Micro-Supercapacitors with AC Line Filtering Performance.

Coordination polymer frameworks (CPFs) have broad applications due to their excellent features, including stable structure, intrinsic porosity, and others. However, preparation of thin-film CPFs for energy storage and conversion remains a challenge because of poor compatibility between conductive substrates and CPFs and crucial conditions for thin-film preparation. In this work, a CPF film was prepared by the coordination of the anisotropic four-armed ligand and CuII at the liquid-liquid interface. Such film-based micro-supercapacitors (MSCs) are fabricated through high-energy scribing and electrolytes soaking. As-fabricated MSCs displayed high volumetric specific capacitance of 121.45 F cm-3 . Besides, the volumetric energy density of MSCs reached 52.6 mWh cm-3 , which exceeds the electrochemical performance of most reported CPF-based MSCs. Especially, the device exhibited alternating current (AC) line filtering performance (-84.2° at 120 Hz) and a short resistance capacitance (RC) constant of 0.08 ms. This work not only provides a new CPF for MSCs with AC line filtering performance but also paves the way for thin-film CPFs preparation with versatile applications.

Charged membranes based on spider silk-inspired nanofibers for comprehensive and continuous purification of wastewater.

Creating a facile and efficient porous membrane for the comprehensive treatment of both insoluble and soluble pollutants from water is of great significance, yet remains challenging. Here, we present a facile strategy to prepare charged nanofibrous membranes assembled from spider silk-like humped SiO2/polyamide 66 (PA66)/polyaniline (PANI) nanofibers by combing Plateau-Rayleigh instability-induced assembly andin situsynthesis. The obtained nanofibrous membranes possess micro/nanostructured surfaces with promising superhydrophilic and underwater superoleophobic property, which are attributed to the synergy of hierarchical roughness and hydrophilic matrix. Combined with the superwettability and the integrated property of submicron pore size, high porosity, and good pore interconnectivity, the membranes can separate various oil-in-water emulsions with a remarkable permeation flux of 5403 l m-2h-1and a high separation efficiency (total organic carbon content <5 mg l-1). Moreover, attributed to the Laplace pressure difference and positive potential of the spindle-knotted nanofibers, the biomimetic nanofibrous membranes could remove the filter cake during separation. In addition, the membrane exhibits a remarkable adsorption-reduction capacity of hexavalent chromium. The synthesis of such attractive nanomaterials may provide new insights into the development of multifunctional separation materials for environmental applications.

[Arachidonic acid Alox15/12-HETE signaling inhibits vascular calcification].

This study aims to explore the effects of arachidonic acid lipoxygenase metabolism in vascular calcification. We used 5/6 nephrectomy and high-phosphorus feeding to establish a model of vascular calcification in mice. Six weeks after nephrectomy surgery, vascular calcium content was measured, and Alizarin Red S and Von Kossa staining were applied to detect calcium deposition in aortic arch. Control aortas and calcified aortas were collected for mass spectrometry detection of arachidonic acid metabolites, and active molecules in lipoxygenase pathway were analyzed. Real-time quantitative PCR was used to detect changes in the expression of lipoxygenase in calcified aortas. Lipoxygenase inhibitor was used to clarify the effect of lipoxygenase metabolic pathways on vascular calcification. The results showed that 6 weeks after nephrectomy surgery, the aortic calcium content of the surgery group was significantly higher than that of the sham group (P < 0.05). Alizarin Red S staining and Von Kossa staining showed obvious calcium deposition in aortic arch from surgery group, indicating formation of vascular calcification. Nine arachidonic acid lipoxygenase metabolites were quantitated using liquid chromatography/mass spectrometry (LC-MS) analysis. The content of multiple metabolites (12-HETE, 11-HETE, 15-HETE, etc.) was significantly increased in calcified aortas, and the most abundant and up-regulated metabolite was 12-HETE. Furthermore, we examined the mRNA levels of metabolic enzymes that produce 12-HETE in calcified blood vessels and found the expression of arachidonate lipoxygenase-15 (Alox15) was increased. Blocking Alox15/12-HETE by Alox15 specific inhibitor PD146176 significantly decreased the plasma 12-HETE content, promoted calcium deposition in aortic arch and increased vascular calcium content. These results suggest that the metabolism of arachidonic acid lipoxygenase is activated in calcified aorta, and the Alox15/12-HETE signaling pathway may play a protective role in vascular calcification.

Subnanometer Bimetallic Platinum-Zinc Clusters in Zeolites for Propane Dehydrogenation.

Propane dehydrogenation (PDH) has great potential to meet the increasing global demand for propylene, but the widely used Pt-based catalysts usually suffer from short-term stability and unsatisfactory propylene selectivity. Herein, we develop a ligand-protected direct hydrogen reduction method for encapsulating subnanometer bimetallic Pt-Zn clusters inside silicalite-1 (S-1) zeolite. The introduction of Zn species significantly improved the stability of the Pt clusters and gave a superhigh propylene selectivity of 99.3 % with a weight hourly space velocity (WHSV) of 3.6-54 h-1 and specific activity of propylene formation of 65.5 mol C 3 H 6 gPt -1 h-1 (WHSV=108 h-1 ) at 550 °C. Moreover, no obvious deactivation was observed over PtZn4@S-1-H catalyst even after 13000 min on stream (WHSV=3.6 h-1 ), affording an extremely low deactivation constant of 0.001 h-1 , which is 200 times lower than that of the PtZn4/Al2 O3 counterpart under the same conditions. We also show that the introduction of Cs+ ions into the zeolite can improve the regeneration stability of catalysts, and the catalytic activity kept unchanged after four continuous cycles.