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Classical strong metal–support interaction (SMSI) has attracted intensive attention in the heterogeneous catalysis field; however, its crystalline TiOx overlayer and reversible feature often curtai...

Ring-opening copolymerization (ROCOP) of epoxide/anhydride/CO2 for the synthesis of CO2-based copolymers is a promising process, because CO2 is an abundant, nontoxic, and low-cost monomer and has b...

The development of homogeneous metal catalysts with high activity and high thermal stability is vital for the synthesis of polyolefin elastomers (POEs) in solution-phase olefin polymerization proce...

In order to examine the possibility to promote cooperative effects on catalytic activity and selectivity in ethylene dimerization through ligand design, the bisphosphino-iminato ligands syn-L and a...

Phosphazenes as organocatalysts for the synthesis of polymers have evolved to powerful tools, and their catalytic performances highly depend on the basicity and molecular structure (size and shape). Therefore, designing phosphazenes with tunable basicity and molecular structure is greatly promising for the development of organocatalysts with improved catalytic properties, for example, high activity and selectivity. In this contribution, 2,4,6-tris[tri(dimethylamino)iminophosphorane]-1,3,5-triazine (C

Dinuclear titanium complexes syn-Ti2 and anti-Ti2 bearing anthracene-bridged bisphenoxyimine ligands (syn-L and anti-L) have been prepared and characterized by NMR and elemental analyses. The molecular structure of syn-Ti2 was defined by X-ray diffraction, revealing a separation of 7.183 A between the two Ti centers. The mononuclear complex [(2,6-iPr2-C6H3NCH-C6H2-3,5-tBu-2-O)­TiCl3(THF)] (Ti1) was also prepared for control experiments. In the presence of MAO as a cocatalyst, syn-Ti2 and anti-Ti2 were active toward ethylene homopolymerization but had distinct catalytic properties. The complex syn-Ti2 with a shorter metal–metal separation exhibited higher activity and produced polymers with higher molecular weights, in comparison to anti-Ti2, having a longer metal–metal separation, and the mononuclear catalyst control Ti1 under identical conditions. More importantly, the complex syn-Ti2 exhibited excellent thermal stability and thus the a greater activity can be obtained at 100 °C, which is a preferred temperature for industrial operations. For ethylene/1-hexene copolymerization, the activity, Mw, and incorporation of 1-hexene by syn-Ti2 were 2.3×, 3.2×, and 6.0× those of anti-Ti2 under identical conditions.

Supported gold catalysts play a crucial role in the chemical industry; however, their poor on-stream stability because of the sintering of the gold nanoparticles restricts their practical application. The strong metal-support interaction (SMSI), an important concept in heterogeneous catalysis, may be applied to construct the structure of catalysts and, hence, improve their reactivity and stability. Here we report an ultrastable Au nanocatalyst after calcination at 800 °C, in which Au nanoparticles are encapsulated by a permeable TiOx thin layer induced by melamine under oxidative atmosphere. Owning to the formed TiOx overlayer, the resulting Au catalyst is resistant to sintering and exhibits excellent activity and stability for catalytic CO oxidation. Furthermore, this special strategy can be extended to colloidal Au nanoparticles supported on TiO2 and commercial gold catalyst denoted as RR2Ti, providing a universal way to engineer and develop highly stable supported Au catalysts with tunable activity., Sintering-resistant Au nanoparticles are highly desirable due to their low Tammann temperature. Here, the authors report an ultrastable titania-supported Au nanocatalyst through an encapsulation strategy under oxidative atmosphere.

We demonstrated that the dimeric 1-tert-butyl-2,2,4,4,4-pentakis(dimethylamino)-2Λ5, 4Λ5-catenadi(phosphazene) supported on polystyrene (PS-t-BuP2) was an efficient and recyclable catalyst for the ring-opening polymerization (ROP) of δ-valerolactone (δ-VL). The heterogeneous catalyst PS-t-BuP2 could be recycled and reused for five consecutive cycles without significant decrease of catalytic activity. The monomer conversions maintained between 79% and 85% for five cycles. Using BnOH as initiator, the produced polyvalerolactones (PVLs) had controlled molecular weights (MWs) and narrow MW distributions (Đ), and the products were free of catalyst by simple filtration. The 1H NMR and MALDI-TOF characterizations of the obtained PVLs clearly indicated the presence of the initiator residue at the chain end.

Monodisperse gold particles (ca. 2 nm) were prepared and deposited on various supports (SiO2, Al2O3, HAP, MgAl2O4 and MgO). The acid/base properties of supports were characterized by NH3 and CO2 sorption. The size of the gold nanoparticles spans in the 1.7–6.5 nm mean diameter range after calcination as determined from TEM measurements. The amounts of accessible surface sites were estimated by binary concentration pulse chromatography of CO with Kr adsorption. The data are in agreement with the results of CO adsorption obtained by DRIFT spectroscopy. The activities of the catalysts were compared in the oxidation of benzyl alcohol in stirred batch reactors under two different conditions: in xylene solvent with atmospheric oxygen at 60 °C (in presence and in absence of K2CO3), and in a solvent-free mixture at elevated pressure and temperature (5 bar O2, 150 °C, 5 h). The activities of catalysts in benzyl alcohol conversion are described in two variants, namely related to (i) active catalytic sites (ASNA), and (ii) number of Au atoms on the geometric surface of particles (GSNA). The activities of catalysts in xylene solvent at 60 °C were excellent, with 0.28–1.11 s−1 characteristic GSNAini values (initial reaction rates related to surface Au atoms, Ausurf) in presence of K2CO3. The observed order of activities under these conditions is Au/SiO2

Organic small-molecule-based photothermal agents such as cyanine dyes have received increasing attention in developing novel cancer therapies with potential clinical utility but suffer from poor stability, low photothermal efficiency, and limited accumulation at tumor sites in molecular forms. Self-assembly of small-molecule dyes into supramolecular assemblies may address these concerns by controlling the molecular organization of dye monomers to form structures of a higher order. Among them, H-aggregates of dyes favor face-to-face contacts with strongly overlapping areas, which always have a negative connotation to exhibit low or no fluorescence in most cases but may emanate energy in nonradiative forms such as heat for photothermal cancer therapy applications. Here, the synergistic self-assembly of cyanine dyes into H-aggregates is developed as a new supramolecular strategy to fabricate small-molecule-based photothermal nanomaterials. Compared to the free cyanine dyes, the H-aggregates assembled from pyrene or tetraphenylethene (TPE) conjugating cyanine exhibit the expected absorption spectral blue shift and fluorescence self-quenching but unique photothermal properties. Remarkably, the obtained H-aggregates are saucer-shaped nanoparticles that exhibit passive tumor-targeting properties to induce imaging-guided photothermal tumor ablation under irradiation. This supramolecular strategy presented herein may open up new opportunities for constructing next-generation small-molecule-based self-assembly nanomaterials for PTT cancer therapy in clinics.

Phosphazenes have attracted considerable attention in the field of ring-opening polymerization (ROP) of cyclic esters. However, the application of phosphazenes as catalyst is subject to a trade-off between activity and selectivity (chain propagation versus transesterification/back-biting reaction, e.g., controlled polymerization). Despite extensive research efforts, the development of a new catalytic system having concurrent high activity and selectivity remains a great challenge. In this work, we report that the binary organocatalytic system comprised of cyclic trimeric phosphazene base (CTPB) and ureas shows both of high activity and selectivity for the ROP of e-caprolactone (e-CL) and δ-valerolactone (δ-VL) in the presence of alcohol as initiator. It is found that the introduction of ureas would significantly increase the catalytic selectivity during ROP without sacrificing the catalytic activity of CTPB. Moreover, the polymerizations catalyzed by the title catalytic system exhibit immortal characteristics and thus thousands equivalent of monomer could be converted to polymer efficiently with desired MWs and microstructures. Linear diblock copolymer AB and star copolymers (AB)3 with three identical diblock arms could be readily synthesized by sequential copolymerization using different alcohols as initiators.

Degradable long-chain aliphatic polyesters are promising alternatives to polyolefins. The ring-opening polymerization (ROP) of ω-pentadecalactone (PDL) enables the synthesis of aliphatic polyesters with melting temperature close to low-density polyethylene (LDPE). However, this ROP reaction is of great challenge because of low ring strain of the PDL monomer. The occurrence of intra- and intermolecular transesterification reactions during ROP made it difficult to prepare well-defined block copolyesters for advanced properties. In this context, cyclic trimeric phosphazene base (CTPB) in combination with benzyl alcohol (BnOH) was proved to be an efficient initiator system for ROP of PDL, showing an excellent polymerization rate (TOF up to 600 h–1) at 80 °C. Well-defined diblock copolyesters, i.e., PPDL-b-PLLA, can be easily synthesized by sequential addition of PDL and l-lactide (L-LA). In contrast, sequential addition of PDL and e-caprolactone (CL) or δ-valerolactone (VL) only led to the random copolyesters...

Polysiloxanes containing phenyl functional groups are a class of promising polymer materials with enhanced low-temperature flexibility, high-temperature stability and great damping properties. In this context, organic cyclic trimeric phosphazene bases (CTPBs) have been proved to be highly efficient for the ring-opening polymerization (ROP) of octamethylcyclotetrasiloxane (D4) and the copolymerization of D4 with octaphenylcyclotetrasiloxane (P4) under mild conditions. The polymerizations are fast and the resulting polymers have high molecular weights (Mn up to 1353 kg mol−1). The molecular structures of the obtained copolysiloxanes were characterized by 1H NMR and 29Si NMR, which demonstrate that as high as 64 mol% diphenyl siloxane units can be incorporated within the copolysiloxane chain. Remarkably, copolysiloxanes with different contents of the diphenyl siloxane group are found free of T-branches and Q-branches based on the 29Si NMR analysis, indicating a good controlled ROP by the current organocatalytic system. DSC analysis shows no crystallization exotherm or melting endotherm in the range of −70 °C to 50 °C for all the copolysiloxanes, confirming that incorporation of diphenyl groups successfully suppresses the undesirable crystallization of polydimethylsiloxane. Moreover, the thermal stability of copolysiloxanes was evaluated by TGA, showing dramatically enhanced thermal stability with the increment of the diphenyl siloxane content.

The chemosynthesis of bio-renewable poly(γ-butyrolactone) (PγBL) with a high molecular weight via ring opening polymerization (ROP) of non-strained γ-butyrolactone (γBL) remains a big challenge although several catalysts have been developed in the past two years. In this contribution, we reported the efficient ROP of γBL using a strong base/urea binary synergistic catalytic system. Either an alkaline alkoxide or organophosphazene superbase was used as a strong base in this study. The base/urea binary catalyst showed high catalytic activity and high selectivity for ring opening relative to transesterification toward the ROP of γBL, and the organophosphazene superbase in combination with urea showed better catalytic activity compared to an alkaline alkoxide/urea system. The effects of bases, ureas, and reaction conditions on monomer conversions and resultant molecular weights of PγBL were systematically investigated. A PγBL homopolymer with a high molecular weight up to 35.0 kDa was synthesized using a combination of a cyclic trimeric phosphazene superbase (CTPB) and suitable ureas with electron-donating substituents. The thermal stabilities of PγBL improved dramatically with an increase in its molecular weight. The obtained PγBL exhibited unprecedented superior mechanical properties with an elongation at break of 858 ± 79%, which paves the way for its practical applications.

In the K-storage process, graphitic carbon exhibits unique practical plateau potential but suffers terrible rate and cycle performance, because its perfect long-range ordered carbon structure, small lattice space and high contact/interface resistance are still bottlenecks to limit the kinetics and structural stability. Herein, we prepare a novel interface-free integrative graphitic carbon network film on a large scale, and enlarged its lattice distance and reasonably introduce defects (ED-IGCN) to boost kinetics and cyclability via a plasma-enhanced etching/S-doping process. Typically, the ED-IGCN entails ultra-thin hollow graphitic units (diameter ∼10 nm, shell wall ∼1 nm) interconnected by sp2 hybrid covalent bonds, providing an interface-free highly conductive network. Additionally, the defective long-range ordered carbon arrangement and enlarged lattice distance ensured numerous open channels and shortened pathways with low diffusion barrier for boosting the fast (de)potassiation kinetics. When applied in PIB, the ED-IGCN anodes delivered a high reversible capacity of 408 mAh g-1 at 20 mA g-1, and ultra-high rate and long-term cyclability without expensing its unique discharge plateau. The capacity maintained up to 91.1 mA h g-1 after 10000 cycles at 5 A g-1 with a capacity retention of ∼60% (∼51% after 11000 cycles), which is not inferior to that of any graphitic carbon reported previously. We separated the diffusive capacity, and pseudo-/double-layer capacitive contributions, and verified that the plasma treating process enhanced the capacitive K-storage mechanism which give great contribution to the fast kinetics. A full-cell based on potassium Prussian blue (KPB) cathode and ED-IGCN anode delivered an initial reversible capacity of 177 mAh g-1 at 1000 mA g-1, and retained ∼70% after 50 cycles, further demonstrating the ultra-high rate capability of ED-IGCN in practical application. The results provide new insights into the design and structure regulations of graphitic carbon for fast-charging batteries with stable working voltages and an understanding of the diffusion acceleration mechanism in graphitic carbon materials.

Porous organic polymers (POPs) have been considered as prominent adsorbents for volatile iodine. So far, both crystalline and amorphous POPs have accomplished excellent iodine capture capability. Considering the difficulty and challenges in preparing perfect crystalline POPs, more explorations into developing versatile amorphous POPs are needed. Herein, amorphous POPs based on the Schiff-base reaction were designed and synthesized for volatile iodine removal. Four amorphous POPs products named as NDB-H, NDB-S, ADB-HS, and ADB-S obtained under different solvothermal conditions were investigated in terms of their morphologies, porosity, and their iodine enrichment performance in detail. It is noteworthy that excellent efficiency for removing iodine vapor was acquired for NDB-S (≈425 wt %), ADB-HS (≈345 wt %), and ADB-S (≈342 wt %). Remarkably, NDB-H exhibited an iodine capture capacity up to ≈443 wt %. Excellent reusability was obtained as well. Amorphous NDB-H has accomplished an extremely high iodine capture performance, illustrating the great chance to exploit versatile amorphous POPs for iodine enrichment and removal based on Schiff-base chemistry.

The binuclear salphen Ti polymerization catalyst N,N′-1,2-phenylene[(salicylideneaminato)Ti(Cp*)Me2)]2 (2) is synthesized by reaction of salphen-H2 with Cp*TiMe3. Mononuclear [N-(2,6-diisopropyl)phenyl(salicylideneaminato)]Ti(Cp*)Me2 (1) serves as a control. Activation studies of 2 with cocatalyst Ph3C+B(C6F5)4– yield the cationic polymerization-inactive complex [N,N′-1,2-phenylene(salicylideneaminato)Ti(Cp*)]+B(C6F5)4– (4) and polymerization-active Cp*TiMe2+B(C6F5)4–. Polymerization studies comparing 2 with Cp*TiMe3 suggest that, within the catalytic time frame, while 2 retains bimetallic character under an ethylene atmosphere, it rapidly decomposes to 4 and Cp*TiMe2+ in the presence of 1-hexene. These monomer-dependent reorganization results highlight the importance of olefin polymerization activation mechanistic studies while providing insight for improved bimetallic catalyst design.

Phosphazene base is an important organocatalyst in polymer chemistry owing to its high activity and versatility. In this contribution, we demonstrate that cyclic trimeric phosphazene base (CTPB) can catalyze stereoselective ring-opening polymerization (ROP) of rac-lactide (rac-LA) to produce isotactic stereoblock PLA (Pi up to 0.93). The polymerizations are highly controlled, as evidenced by linear relationship between molecular weights (MW) and monomer conversions and the narrow dispersity (Đ = Mw/Mn) of the resulted polymers with high fidelity of end groups. The investigations on polymerization parameters show that the tacticity of produced PLA depends on the polymerization temperatures and solvents, while the kinetic studies reveal a faster rate for ROP of l-LA as compared to rac-LA under same conditions. Based on these results, the chain end control mechanism is proposed to explain the production of isotactic stereoblock PLA from rac-LA by an achiral catalyst.

Exogenous dietary advanced glycation endproducts (AGEs) have been suggested to increase health risk. Oral use tobacco products are used as substitute for cigarette smoking due to their “reduced risk” and no second-hand smoke. They may increase AGEs intake due to their oral form of use. However, research on AGEs in oral use tobacco products is limited. A HPLC-MS/MS method was developed to survey free and total Ne-Carboxymethyllysine (CML) and Ne-Carboxyethyllysine (CEL) levels in different oral use tobacco products in this work. HPLC conditions, such as HPLC column and mobile phase additive were optimized. With the optimized conditions, analytical method performance for three types of oral use tobacco matrix (i.e. CRP2, gum and dissolvable tobacco product) was characterized. CML and CEL showed higher recovery in all three sample matrix, and the recovery of CML and CEL was in the range of 88.7%-120%, 90.0%-110%, respectively. The developed method showed good intra-day and inter-day precision with RSDs for both free and total CML (or CEL) of less than 9.7%. Limit of detections (LODs) of CML and CEL were 0.36 and 0.25 ng/mL, respectively. Sample analysis for 21 oral use tobacco products was conducted with the developed method. As for oral use tobacco products, total CML and CEL was much more than those of their free state, indicating that CML and CEL exist mainly protein adducts. In addition, the content of CML was higher than that of CEL for both free and total state. Oral use tobacco products I (i.e. dry snuff, moist snuff, suns and chew) had the highest CML (i.e. 44.89–608.69 µg/g) and CEL (i.e. 15.98–77.70 µg/g) levels, compared with oral use tobacco products II (i.e. gum) with the least CML (i.e. 0.7–0.8 µg/g) and CEL (i.e. 0.14–0.18 µg/g) levels. It mainly depended on the composition and processing technology of oral use tobacco products. Both total CML and CEL showed linear relationship with lysine and total amino acid (i.e. R > 0.77). However, there was no linear relationship between total CML (or CEL) and total reducing carbohydrates (i.e. R

Catalysts CuCl2/13X were prepared from the combination of 13X zeolite and copper chloride, and they exhibited excellent stability and vinyl chloride monomer (VCM) selectivity in acetylene hydrochlorination. The effects of copper chloride loading amount, reaction temperature, acetylene space velocity and pretreatment temperature on CuCl2/13X catalyst’s catalytic performance were investigated. It was found that after pretreatment under 300 °C, 25CuCl2/13X displayed the best catalytic performance at reaction temperature of 220 °C and acetylene space velocity of 30 h−1, and its acetylene conversion and VCM selectivity was higher than 78% and 99%, respectively, and the catalyst’s reactivity slightly increased after 16-h reaction. Different techniques including low temperature physical adsorption of nitrogen, breakthrough experiment, thermogravimetric analysis (TG), differential scanning calorimetry (XRD) and X-ray diffraction (XRD) were employed to characterize the catalysts. The results demonstrated that the strong HCl adsorption ability of CuCl2/13X catalyst and the enhancement between 13X and copper chloride explained why the catalytic performance of CuCl2/13X was better than that of CuCl2/AC.

The complex (μ-Me2C-3,3′){(η5-cyclopentadienyl)[1-Me2Si-(tBuN)](TiMe2)}2 (3) was prepared as a new binuclear catalyst motif for homogeneous olefin polymerization. Complex 3 exists as rac-3 and meso-3 diastereomers, which can be separated and characterized by solution NMR spectroscopy and single-crystal X-ray diffraction. While meso-3 has high thermal stability, rac-3 undergoes thermolysis in solution to quantitatively form the dimeric methylidene complex (μ-Me2C-3,3′){(η5-cyclopentadienyl)[1-Me2Si(tBuN)][(μ-CH2)Ti]}2 (rac-4). Activation of rac-3 and meso-3 with 1 equiv of Ph3C+B(C6F5)4– yields [(μ-CMe2-3,3′){(η5-cyclopentadienyl)[1-Me2Si(tBuN)]}2(μ-CH2)(μ-CH3)Ti2]+B(C6F5)4– (5; rac-5 and meso-5, respectively). Interestingly, meso-5 is stable in the presence of an additional 1 equiv of Ph3C+B(C6F5)4–, while rac-5 reacts to yield rac-[(μ-CMe2-3,3′){(η5-cyclopentadienyl)[1-Me2Si(tBuN)]}2(μ-CH2)[(TiCH3)(Ti-η1-Ph3C)]2+[B(C6F5)4–]2 (rac-6) as indicated by multinuclear NMR spectroscopy and DFT computation. meso-...

Two types of bifunctional bis(salicylaldimine) ligands (syn-L and anti-L) were designed and synthesized to support bimetallic aluminum complexes. Owing to the rigid anthracene skeleton, syn-L and anti-L successfully locked two Al centers in close proximity (syn-Al2) and far apart (anti-Al2), respectively. The distance between two Al centers in syn-Al2 was defined by X-ray diffraction as 6.665 A, which is far shorter than that in anti-Al2. In the presence of stoichiometrical BnOH, syn-Al2 and anti-Al2 were both efficient for ring-opening polymerization (ROP) of rac-LA with the former being more active. In the presence of excess BnOH, syn-Al2 showed an efficient and immortal feature, consistent with high conversions, matched Mns, narrow molecular weight distributions and end group fidelity, while anti-Al2 had a much lower activity or even became entirely inactive due to rapid decomposition, indicated by in situ1H-NMR experiments of Al complexes with BnOH.

A new superbase, cyclic trimeric phosphazene base (CTPB), was prepared with high yield and purity. In the presence of alcohol, the CTPB can serve as highly efficient organocatalyst for ring-opening polymerization (ROP) of "non-polymerizable" γ-butyrolactone to offer well-defined poly(γ-butyrolactone) with high conversions (up to 98%) at -60 °C. The produced polymers have high molecular weights (up to 22.9 kg·mol-1) and low polydensity distributions (1.27-1.50). NMR analysis of initiation process and the structural analysis of resulted polymers by MALDI-TOF suggest an activating initiator mechanism that is responsive for linear polymer as only product with designed BnO/H chain ends.

The unsymmetrical salphen ligand (3,5-tBu-1-OH-C6H2)CH═N-C6H4-N═CH(3-Ph-1-OH-C6H3) (tBu-PhLH2) was designed and synthesized to support aluminum complexes. Its symmetric analogues, (3,5-tBu-1-OH-C6H2)CH═N-C6H4-N═CH(3,5-tBu-1-OH-C6H2) (tBuLH2) and (3-Ph-1-OH-C6H3)CH═N-C6H4-N═CH(3-Ph-1-OH-C6H3) (PhLH2), were also explored and compared. The methane elimination reactions between ligands and AlMe3 resulted in formation of tBu-PhLAlMe (1), tBuLAlMe (2), and PhLAlMe (3) in high yields, which were characterized by elemental analysis, 1H and 13C NMR. The coordination geometries of unsymmetrical and symmetric ligands in 1 and 2 were studied by X-ray diffractions, which revealed a five-coordinated distorted square-pyramidal geometry around Al centers. The aluminum methyl compounds 1–3 reacted with BnOH at 70 °C to give tBu-PhLAlOBn (4), tBuLAlOBn (5), and PhLAlOBn (6), respectively, which existed as monometallic species in solution as indicated by NMR studies. However, the aluminum isopropoxide prepared by the reacti...

c-Myc coordinates context-dependent homeostasis and transitional activation with metabolic programming of regulatory T cells., Regulatory T cell (Treg) activation and expansion occur during neonatal life and inflammation to establish immunosuppression, yet the mechanisms governing these events are incompletely understood. We report that the transcriptional regulator c-Myc (Myc) controls immune homeostasis through regulation of Treg accumulation and functional activation. Myc activity is enriched in Tregs generated during neonatal life and responding to inflammation. Myc-deficient Tregs show defects in accumulation and ability to transition to an activated state. Consequently, loss of Myc in Tregs results in an early-onset autoimmune disorder accompanied by uncontrolled effector CD4+ and CD8+ T cell responses. Mechanistically, Myc regulates mitochondrial oxidative metabolism but is dispensable for fatty acid oxidation (FAO). Indeed, Treg-specific deletion of Cox10, which promotes oxidative phosphorylation, but not Cpt1a, the rate-limiting enzyme for FAO, results in impaired Treg function and maturation. Thus, Myc coordinates Treg accumulation, transitional activation, and metabolic programming to orchestrate immune homeostasis.

In accordance with the life cycle cost of the vehicle, the structure of the aluminum alloy car body structure of Shanghai Line 16 was optimized based on the Optistruct software. Then the load combination conditions are divided into 9 operating conditions based on EN12663-2010. Furthermore, the optimized car body is judged whether it is qualified. The experimental results show that the optimized car body structure of Shanghai Line 16 can meet EN12663 and TB/T1335. In this paper, it provides a high application prospect for reducing LCC of the aluminum alloy car body in the design stage.

At different temperatures, we test the charge and discharge performance of lithium iron phosphate power batteries after retirement, and study the effect of temperature on the performance of decommissioned batteries, including the test of capacity and energy, and the battery voltage test. Experimental results show that low temperature will lead to a decrease in charge and discharge capacity and energy, and affect the performance of decommissioned batteries.

As for the BAK 18650 lithium iron phosphate battery, combining the standard GB/T31484-2015(China) and SAE J2288-1997(America), the lithium iron phosphate battery was subjected to 567 charge-discharge cycle experiments at room temperature of 25°C. The results show that the SOH of the battery is reduced to 80% after 240 cycle experiments, which meets the requirements of aging and decommissioning. Calendar aging has a side effect on the experiment. As for the aging process of the battery, it provides experimental support for improving the service life of the battery.

In accordance with the structural performance shortages of the lightweight subway, the verification of the strength and stiffness of subway vehicles is proposed. Then the load combination conditions are divided into 9 operating conditions based on EN12663-2010. With the aid of Abaqus software, the strength and stiffness are judged whether it is qualified. The experimental results show that the aluminum alloy car body structure of Shanghai Line 16 can meet EN12663 and TB/T1335. In this paper, it provides a verification process for the reliability of the strength and stiffness of subway aluminum alloy car body.

Amadori compounds, are known as aroma precursors formed in the initial phase of the Maillard reaction. Based on their similar structures, simultaneous quantification of more than six Amadori compounds in tobacco has not been reported yet. In this study, a simple and rapid method was developed to simultaneously quantify ten Amadori compounds including the isomers of Fructose-isoleucine and Fructose-leucine in tobacco. The separation was performed on an Atlantis T3 column (2.1×250 mm, 5 μm) by gradient elution using acetonitrile and water as the mobile phases. The quantification method was systematically evaluated and proven to be sensitive and accurate. The linearity was good, with correlation coefficients of 0.9977–0.9999. The limits of detection and quantitation were 1.354–2.532 and 4.516–8.444 ng/mL, respectively. The recoveries were 84.0–119.6%, and the relative standard deviations were 1.33–5.40%. The method was used to analyze the changes in the amounts of ten Amadori compounds in tobacco before and after tobacco primary processing. The analysis shows that Maillard reaction occurs during the short processing period. This article is protected by copyright. All rights reserved

The stoichiometric reaction of bis-phenolate ligands with AlMe3 afforded zwitterionic aluminum complexes Al1-Al3, which were characterized by NMR spectroscopy and elemental analysis. The solid state structure of Al2 was determined by single-crystal X-ray diffraction, which revealed a dinuclear feature. Two Al centers were bridged by two ligands and thus formed an unusual large 24-membered-ring metallacycle. In the presence of BnOH, Al1-Al3 were efficient for the ring-opening polymerization of e-caprolactone in a controlled manner, and the efficiency was affected by substituents on the ligands. The polymerizations exhibited a feature of immortal catalysis with an excess of BnOH.

Poly(e-caprolactones) (PCLs) with low catalyst loading and high molecular weights are highly desired considering their practical applications. In this work, cyclic trimeric phosphazene base (CTPB) has been developed and applied as an efficient organocatalyst in the ring-opening polymerization (ROP) of e-caprolactone (e-CL). It is found that CTPB could directly catalyze the ROP of e-CL but with a relatively low activity. In contrast, CTPB with alcohol as the initiator exhibits extremely high efficiency toward the ROP of e-CL and rapidly converts hundreds even thousands equiv. monomers into PCLs with high conversions and controlled and high molecular weights. Both mono- and multi-hydroxy-alcohols are efficient as initiators, and thus PCLs with different topologies can be easily prepared. Moreover, with excess of alcohol, the title catalytic system represents a rare example of immortal polymerization by an organocatalyst for e-CL.

A method was developed for the determination of nine volatile N-nitrosamines in tobacco and smokeless tobacco products. The targets are N-nitrosodimethylamine, N-nitrosopyrrolidine, N-nitrosopiperidine, N-nitrosomorpholine, N-nitrosoethylmethylamine, N-nitrosodiethylamine, N-nitrosodipropylamine, N-nitrosobuylmethylmine, and N-nitrosodibutylamine. The samples were treated by dispersive solid-phase extraction using 1 g of primary secondary amine and 0.5 g of carbon and then analyzed by gas chromatography with tandem mass spectrometry with an electron impact ion source. The recoveries for the targets ranged from 84 to 118%, with

Ultrahigh molecular weight polyethylene (UHMWPE) is a class of high-performance engineering plastics, exhibiting a unique set of properties and applications. Although many advances have been achieved in recent years, the synthesis of UHMWPE is still a great challenge. In this contribution, a series of zirconium and hafnium complexes, [2,6-(R1)2-4-R2-C6H2-N-C(camphyl)=C(camphyl)-N-2,6-(R1)2-4-R2-C6H2]MMe2(THF) (1-Zr: R1 = Me, R2 = H, M = Zr; 2-Zr: R1 = Me, R2 = Me, M = Zr; 1-Hf: R1 = Me, R2 = H, M = Hf; 2-Hf: R1 = Me, R2 = Me, M = Hf), bearing bidentate NN ligands with the bulky camphyl backbone were synthesized by the stoichiometric reactions of α-diimine ligands with MMe4 (M = Hf or Zr). All Zr and Hf metal complexes were analyzed using 1H and 13C NMR spectroscopy, and the molecular structures of complexes 1-Zr and 1-Hf were determined by single-crystal X-ray diffraction, revealing that the original α-diimine ligand was selectively reduced into the ene-diamido form and generated an 1,3-diaza-2-metallocyclopentene ring in the metal complexes. Zr complexes 1-Zr and 2-Zr showed moderate activity (up to 388 kg(PE)·mol−1(M)·h−1), poor copolymerization ability, but unprecedented molecular weight capability toward ethylene/1-octene copolymerization. Therefore, copolymers with ultrahigh molecular weights (> 600 or 337 × 104 g∙mol−1) were successfully synthesized by 1-Zr or 2-Zr, respectively, with the borate cocatalyst [Ph3C][B(C6F5)4]. Surprisingly, Hf complexes 1-Hf and 2-Hf showed negligible activity under otherwise identical conditions, revealing the great influence of metal centers on catalytic performances.

Knowledge of the deposition of inhaled smoke aerosol in the human respiratory tract has great value for risk assessments of the inhalation toxicology of tobacco products. In this study, differential mobility spectrometry (DMS) was used to characterize smoke particles generated from a conventional cigarette, e-cigarette and heat-not-burn product. The aerosol properties obtained by DMS were then applied to a Multiple Path Particle Dosimetry (MPPD) model to predict the deposition of aerosol particles in the human respiratory tract. The DMS results showed that the particle size distribution of aerosol from the three products differed considerably, with a count median diameter of 14.2–25.4 nm, 50.6–55.3 nm and 172–179 nm for the e-cigarette, heat-not-burn product and conventional cigarette, respectively. However, there was no significant difference in the particle number concentration of aerosol from the three products. The MPPD model indicated that the total deposition fraction of aerosol particles from the e-cigarette and heat-not-burn product was higher than that from the conventional cigarette, and deposition of particles from the e-cigarette in the three human airway regions (head airway, tracheobronchial and pulmonary regions) was higher than that from the heat-not-burn product and conventional cigarette; the particle number concentration deposited in the pulmonary region was the highest, comprising more than 60% of total deposition. Lastly, among the lung lobes, the highest number deposition fraction occurred in the right lower lobe. The relationship between deposition fraction and airway generation was relatively similar among the three aerosols, and the highest deposition fraction occurred in the 20th to 23rd generation airways. The deposition results showed that smaller particles, such as those from the e-cigarette aerosol, were more easily deposited in the human respiratory tract. Combined with knowledge of the harmful aerosol constituents, these deposition data will provide important information for hazard evaluation of new tobacco products.

A strategy on amperometric detection for CZE of phenol carbamates as model analytes with a facile in-line thermal hydrolysis was presented, in which a thermal hydrolysis, subsequent CZE separation and final column-end amperometric detection were accomplished in an intact capillary. Key parameters of hydrolysis dynamics of carbamates and electrochemical detection of the hydrolysates were studied, as well as electrophoretic conditions. Under the optimal conditions, the capillary was utilized as chambers for in situ hydrolysis, CZE separation, and electrochemical detection. The successive separation of hydrolysates of five carbamates (propoxur, carbofuran, 3-OH-carbofuran, carbaryl and bendiocarb) were achieved within 17 min. Applied to vegetable samples, the recoveries of carbamates fortified at 0.02 and 0.05 mg/kg were ranging in 88-107.2 and 86.3-107.3%, respectively. The success in the implementation of such a scheme resulted in a simple instrument as compared with those current analytical methods with post-column derivization or pre-column hydrolysis, or online enrichment in chip, respectively. This protocol might possess a potential utility for the sensitive amperometric detection of phenol carbamates.

Chromium-based complexes are among the most important catalysts in the field of ethylene polymerization and oligomerization. Heterogeneous Cr Phillips catalysts account for more than one-third of the commercialized high density polyethylene (HDPE). In this contribution, chromium complexes, LCrCl3 (Cr1-Cr4: L = 2,6-R1-4-R2-C6H2-N[double bond, length as m-dash]CH-C6H4-2-PPh2; Cr1: R1 = H, R2 = H; Cr2: R1 = Me, R2 = H; Cr3: R1 = iPr, R2 = H; Cr4: R1 = Ph2CH, R2 = iPr), have been synthesized and characterized by elemental analysis, ESI and IR spectroscopy. The molecular structures of Cr3 and Cr4 are defined by X-ray diffraction, revealing a distorted octahedral geometry around the chromium center in both structures. In the presence of an aluminum cocatalyst, complexes Cr1-Cr4 show moderate to high activities toward ethylene polymerization. The nature of the catalysts and various reaction conditions, such as the nature and the amount of cocatalyst, reaction time and temperature, are investigated in detail. The results show that the title complexes have good thermal stability and the substituents on the ligands significantly affect the catalytic properties. Particularly, complex Cr4 can produce HDPE with a high molecular weight up to 68.3 × 104 g mol-1 due to the suppression of the chain transfer/termination by the introduction of bulky Ph2CH groups.

Microtubules are an essential component of the cytoskeleton of a eukaryotic cell. The post-translational tubulin modifications play an important role in regulating microtubule properties, acetylation tubulin is one of the major post-translational modifications of microtubules. Acetylation tubulin has also been shown to be expressed in the cochlea. However, the detailed expression profiles of acetylation tubulin protein during development have not yet been investigated in the postnatal mammalian cochlea. Here, we first examined the spatio-temporal expression of acetylated tubulin in the mouse cochlea during postnatal development. At postnatal day 1 (P1), acetylated tubulin was localized primarily to the auditory nerve inside the cochlea and their synaptic contacts with the inner and outer hair cells (IHCs and OHCs). In the organ of Corti, acetylated tubulin occurred first at the apex of pillar cells. At P5, acetylated tubulin first appeared in the phalangeal processes of Deiters’ cells. At P8, staining was maintained in the phalangeal processes of Deiters’ cells and neural elements. At P10, labeling in Deiters’ cells extended from the apices of OHCs to the basilar membrane, acetylated tubulin was expressed throughout the cytoplasm of inner and outer pillar cells. At P12, acetylated tubulin displayed prominent and homogeneous labeling along the full length of the pillar cells. Linear labeling was present mainly in the Deiters’ cell bodies underlying OHCs. Between P14 and P17, acetylated tubulin was strongly expressed in inner and outer pillar cells and Deiters’ cells in a similar pattern as observed in the adult, and labeling in these cells were arranged in bundles. In addition, acetylated tubulin was expressed in stria vascularis, root cell bodies, and a small number of fibrocytes of the spiral ligament until the adult. In the adult mouse cochlea, immunostaining continued to predominate in Deiters’ cells and pillar cells. In Deiters’ cells, immunolabeling formed cups securing OHCs basal portions, and continued presence of acetylated tubulin-labeled nerve terminals below IHCs was shown. Our results presented here underscored the essential role played by acetylated tubulin in postnatal cochlear development, auditory neurotransmission and cochlear mechanics.

N,N′-Bis(2,6-R-phenyl)-2,6-pyridinedicarboxamides (L: R = Cl, L1; R = F, L2; R = H, L3; R = Me, L4; R = Et, L5; R = iPr, L6) were designed as neutral ligands, and the corresponding nickel complexes LNiBr2 (Ni1–Ni6) were synthesized as precatalysts for ethylene oligomerization. All new ligands were fully characterized by NMR, and FT-IR spectroscopy, and elemental analysis, while the nickel complexes were examined using FT-IR spectroscopy and elemental analysis. The coordination mode of the ligand with nickel in complexes Ni5 and Ni6 was tridentate (O^N^O), as established by single crystal X-ray diffractions. All the nickel complexes Ni1–Ni6 were tested for ethylene oligomerization with different alkylaluminum compounds as cocatalysts, and diethylaluminum chloride (Et2AlCl) was proved to be the most effective. Upon activation with Et2AlCl, all nickel complexes showed high catalytic activity (up to 7.55 × 105 g mol−1 (Ni) h−1 atm−1) with good selectivity for α-C4.

The stoichiometric reactions of 8-(2,6-R1-4-R2-anilide)-5,6,7-trihydroquinoline (LH) with AlR3 (R = Me or Et) afforded the aluminum complexes LAlR2 (Al1–Al5,Al1: R1 = iPr, R2 = H, R = Me; Al2: R1 = Me, R2 = H, R = Me; Al3: R1 = H, R2 = H, R = Me; Al4: R1 = Me, R2 = Me, R = Me; Al5: R1 = Me, R2 = Me, R = Et) in high yields. All aluminum complexes were characterized by NMR spectroscopy and elemental analysis. The molecular structures of complexes Al4 and Al5 were determined by single-crystal X-ray diffractions and revealed a distorted tetrahedral geometry at aluminum. In the presence of BnOH, complexes Al1–Al5 efficiently initiated the ring-opening homopolymerization of ε-caprolactone (ε-CL) and rac-lactide (rac-LA), respectively, in a living/controlled manner.

Over the last years, the detection of pesticide residues in the official food surveillance programs of Chile has been increased, mainly in fresh vegetables such as tomatoes and lettuces. The Metropolitana Region of Chile presents the highest detections in the country. The lack of evaluations of toxicological risks in human health have increased uncertainty of the potential effects of pesticides exposures in the Chilean population. This research aims to determinate health risks assessment of pesticide residues associated to tomatoes and lettuces produced in Metropolitana Region. The findings of this study reveal that tomatoes and lettuces cultivated in the MR show more than 50% of samples with one or multiple pesticides residues. From the total samples, 16% were over the Chilean Maximum Residue Levels (MRLs). The main pesticides detected in tomatoes and lettuces were methamidophos, methomyl, difenoconazole, cyprodinil and boscalid. The results obtained using the official data of the Ministry of Health of Chile (MINSAL) compared to the World Health Organization (WHO), describe relevant risks through the Estimated Daily Intakes (EDI), Hazard Quotients (HQ) and Hazard Index (HI) for the Chilean population due to high concentrations of methamidophos, methomyl and cyprodinil. More restrictions for the use of methamidophos, methomyl, difenoconazole, cyprodinil and boscalid and effective control programs should be implemented in order to mitigate the impacts on the Chilean population.

In this work, the effect of TiC additions on the corrosion behaviour of WC–10 wt.% Co hardmetals was investigated in a 1 mol/L NaOH solution. The results showed that the addition of TiC could make the open circuit potential (OCP) in the test solution more positive than the base alloy, lead to nobler free-corrosion potential value and decrease corrosion current density. The XRD results showed that the existence of TiC can inhibit the corrosion of carbide in hardmetals. Moreover, XPS and TEM results demonstrated that titanium dioxide formed in the surface films of the TiC content specimens in the NaOH solution.

Agarwood is a resinous material formed in wounded Aquilaria sinensis in China, which is widely used as an effective traditional Chinese medicine (TCM). This study is aimed to use gas chromatography-mass spectrometry combined with chemometric methods to create reliable criteria for accurate identification of natural agarwood and artificial agarwood, as well as for quality evaluation of artificial agarwood. Natural agarwood and artificial agarwood (stimulated by formic acid or formic acid plus fungal inoculation) were used as standards and controls for the gas chromatography-mass spectrometry (GC-MS) and multivariate analysis. The identification criteria developed were applied to commercial agarwood. A reliable criteria including correlation coefficient of GC-MS fingerprint of natural agarwood and 22 markers of metabolism in natural and artificial agarwood was constructed. Compared with chemically stimulated agarwood (formic acid) and in terms of the 22 markers, artificial agarwood obtained by formic acid stimulation and fungal inoculation were much closer to natural agarwood. The study demonstrates that the chemical components of artificial agarwood obtained by comprehensive stimulated method (formic acid plus fungal inoculation) are much closer to the natural agarwood than those obtained by chemically stimulated method (formic acid), as times goes by. A reliable criteria containing correlation coefficient of GC-MS fingerprint of natural agarwood and 22 metabolism markers can be used to evaluate the quality of the agarwood. As an application case, three samples were identified as natural agarwood from the 25 commercial agarwood by using the evaluation method.

Two novel Mn(II) complexes [Mn(MDPhH2IDC)2(H2O)2] n (1) (MDPhH3IDC = 2-(3,4-methylenedioxyphenyl)-1H-imidazole-4, 5-dicarboxylic acid), [Mn( m-CPhH3IDC)2(H2O)2] n (2) (m-CPh H4IDC = 2-(3-carboxylphenyl)-1H-imidazole-4,5-dicarboxylic acid) have been hydrothermally synthesized with two kinds of imidazole dicarboxylate ligands, respectively, and structurally characterized by elemental analyses, IR spectra, as well as single crystal X-ray diffraction analysis. The 3D solid-state supramolecular structures of the complexes involve intermolecular hydrogen bonds. Furthermore, the thermal and photoluminescent properties of the complexes have been investigated.

Supramolecular nanomedicines, which use supramolecular design to improve the precision and effectiveness of pharmaceutical practice and optimize pharmacokinetic profiles, have gathered momentum to battle cancer and other incurable diseases, for which traditional small-molecular and macromolecular drugs are less effective. However, the lack of clinical approval of supramolecular assembly-based medicine underscores the challenges facing this field. A 2D nanodisc-based supramolecular structure is formed by a non-ionic heptamethine cyanine (Cy7) dye, which generates fluorescence self-quenching but unique photothermal and photoacoustic properties. These Cy7-based supramolecular nanodiscs exhibit passive tumor-targeting properties to not only visualize the tumor by near-infrared fluorescence imaging and photoacoustic tomography but also induce photothermal tumor ablation under irradiation. Due to the nature of organic small molecule, they induce undetectable acute toxicity in mice and can be eliminated by the liver without extrahepatic metabolism. These findings suggest that the self-assembling cyanine discs represent a new paradigm in drug delivery as single-component supramolecular nanomedicines that are self-delivering and self-formulating, and provide a platform technology for synergistic clinical cancer imaging and therapy.

Hyperspectral technology is particularly good at identifying hydrothermally altered minerals and can offer support for three-dimensional (3-D) alteration modeling of hydrothermal deposit. We propose a 3-D alteration modeling method with hyperspectral core imaging to deepen hydrothermal alteration research for uranium exploration of the Heyuanbei uranium deposit in the western Xiangshan ore field, Jiangxi, South China. We use the following three steps: (1) identify and map the altered minerals of drill cores, (2) quantify all types of altered minerals using a pixel classification-based statistical algorithm, and (3) establish 3-D alteration model using a parallel section and a triangulated irregular network. Hyperspectral core imaging data from 14 drill cores from the Heyuanbei uranium deposit are used to establish a 3-D alteration model of the superimposed stratigraphy and structural information by this method. The modeling results indicate that large-scale illite and kaolinite–dickite alterations have developed in the Heyuanbei deposit. The illite alteration has the following obvious zoning characteristics: (1) the spatial correlation of short-wavelength illite and kaolinite–dickite, which developed in two volcanic formations, is high, and the alteration is stronger in the upper part of the drill cores than in the lower part of the drill cores; (2) the long-wavelength illite is mainly distributed in the lower volcanic formations. The zoning characteristics reveal that the hydrothermal fluid is acidic in the upper cores, whereas in the lower cores, alkaline fluid is present, and the fluid environment has the characteristics of a transition from early alkaline to late acidic conditions. Moreover, the short-wavelength illite is more closely related to fluorite-hydromica-type uranium mineralization than the long-wavelength illite, and the conversion action from long-wavelength illite to short-wavelength illite is favorable for uranium enrichment. Thus, short-wavelength illite, kaolinite, dickite, and fluorite can be used as prospective indicators for uranium exploration in the Heyuanbei mining area and nearby areas.