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Methylcyclopentadiene (MCPD) is a widely utilized intermediate in the synthesis of advanced aviation fuels and valuable chemicals. However, the low yield from fossil energy and the high price of MC...

Chiral cyanohydrins are useful intermediates in the pharmaceutical and agricultural industries. In nature, hydroxynitrile lyases (HNLs) are a kind of elegant tool for enantioselective hydrocyanation of carbonyl compounds. However, currently available methods for demonstrating hydrocyanation are still stalled at precise, but low-throughput, GC or HPLC analyses. Herein, we report a chromogenic high-throughput screening (HTS) method that is feasible for the cyanohydrin synthesis reaction. This method was highly anti-interference and sensitive, and could be used to directly profile the substrate scope of HNLs either in cell-free extract or fermentation clear broth. This HTS method was also validated by generating new variants of PcHNL5 that presented higher catalytic efficiency and stronger acidic tolerance in variant libraries.

Poly-lactic acid based biocomposite strengthened with magnesium alloy wires (Mg wires/PLA composite) is prepared for bone fixation implantation. The influence of wire content and load mode on the degradation performances of the composite and its components is studied. The result suggests the degradation of Mg wires could slow down the pH decrease originated from the degradation of PLA, while a relatively high wire content contributes to descend the degradation rate of Mg wire in the composite. Dynamic load significantly promotes the mechanical loss of the specimens. After 30 days immersion, the Sb retention is about 65%, 52% and 55%, respectively for pure PLA, the composite at 10 vol% and 20 vol% under dynamic load, comparing to 75%, 70% and 72% under no load. Moreover, dynamic load could further mitigate the degradation of Mg wires by increasing convective transport of acidic products out of the composite.

Herein, we report a new route for the synthesis of renewable alkylated naphthalenes (ANs) with benzaldehyde and angelica lactone, two platform compounds that can be derived from lignocellulose.

The chiral vicinal C–O/C–N bifunctional groups generated from enzymatic hydrocyanation represents a useful methodology. However, construction of the pharmacophore of β2-adrenoreceptor agonists with...

Aim: The metabolism of tryptophan (TRP) through kynurenine (KYN) and 5-hydroxytryptamine (5-HT) pathways is linked to various diseases such as neurological diseases and cancer. The levels of 5-HT, KYN, TRP can be used as indicators for the diagnosis of various diseases in clinical and scientific research. Experimental: Since 5-HT, KYN, TRP are all endogenous molecules in biological samples, it is difficult to obtain a ‘real blank sample’. A surrogate analyte-based LC–MS/MS method was chosen, using 5-HT-d4, KYN-d4 and TRP-d5 as surrogate analytes to replace the authentic analytes 5-HT, KYN and TRP, respectively. Theophylline was selected as the internal standard (IS). Results: The method was applied to quantification of 5-HT, KYN and TRP of plasma, liver, colon, brain and verified to be acceptable in terms of linearity, precision, accuracy, matrix effect, recovery efficiency and stability.

Structure-guided engineering of Pseudomonas dacunhaeL-aspartate β-decarboxylase (AspBDC) resulted in a double mutant (R37A/T382G) with remarkable 15 400-fold improvement in specific activity reaching 216 mU mg−1, towards the target substrate 3(R)-benzyl-L-aspartate. A novel strategy for enzymatic synthesis of L-homophenylalanine was developed by using the variant as a biocatalyst affording 75% product yield within 12 h. Our results underscore the potential of engineered AspBDC for the biocatalytic synthesis of pharmaceutically relevant and value added unnatural L-amino acids.

Materials with spin dimers have attracted much attention in the last several decades because they could provide a playground to embody simple quantum spin models. For example, the Bose–Einstein condensation of magnons has been observed in TlCuCl3 with anti-ferromagnetic Cu2Cl6 dimers. In this work, we have synthesized a new kind of single-crystal Li11RbGd4Te6O30 with Gd2O15 dimers. This material belongs to the rhombohedral system with the lattice parameters: a = b = c = 16.0948 A and α = β = γ = 33.74°. First-principles calculations indicate that Li11RbGd4Te6O30 is a wide-bandgap (about 4.5 eV) semiconductor. But unlike many other well studied quantum dimer magnets with an anti-ferromagnetic ground state, the Gd2O14 dimers in Li11RbGd4Te6O30 show ferromagnetic intra-dimer exchange interactions according to our calculations. Our work provides a new material which could possibly extend the studies of the spin dimers.

International audience; An orthotropic adhesion model is proposed based on the bi-potential method to solve adhesive contact problems with orthotropic interface properties between hyperelastic bodies. The model proposes a straightforward description of interface adhesion with orthotropic adhesion stiffness, whose components are conveniently expressed according to the local coordinate system. Based on this description, a set of extended unilateral and tangential contact laws has been formulated. Furthermore, we use an elementwise scalar parameter β to characterize the strength of interface adhesive bonds, and the effects of damage. Therefore, complete cycles of bonding and de-bonding of adhesive links with the account for orthotropic interface effects can be modelled. The proposed model has been tested on cases involving both tangential and unilateral contact kinematics. The test cases allowed emergence of orthotropic interface effects between elastomer bodies involving hyperelasticity. Meanwhile, the model can be implemented with minimum effort, and provides inspiration for the modelling of adhesive interface effects in areas of applications such as biomechanics.

Decalin is a jet fuel additive with high thermal stability and energy density. Herein, we reported a novel method for the preparation of decalin from cyclopentanone, a hemicellulose derived cycloke...

The synthesis of renewable jet fuel from lignocellulosic platform compounds has drawn a lot of attention in recent years. So far, most work has concentrated on the production of conventional jet fuels. JP-10 is an advanced jet fuel currently obtained from fossil energy. Due to its excellent properties, JP-10 has been widely used in military aircraft. However, the high price and low availability limit its application in civil aviation. Here, we report a new strategy for the synthesis of bio-JP-10 fuel from furfuryl alcohol that is produced on an industrial scale from agricultural and forestry residues. Under the optimized conditions, bio-JP-10 fuel was produced with high overall carbon yields (≈65 %). A preliminary economic analysis indicates that the price of bio-JP-10 fuel can be greatly decreased from ≈7091 US$/ton (by fossil route) to less than 5600 US$/ton using our new strategy. This work makes the practical application of bio-JP-10 fuel forseeable.

Summary The catalytic conversion of renewable lignocellulose to transportation fuels is crucial to establish energy security and mitigate CO2 emissions. Here, we describe an effective and integrated strategy for the production of high-density aviation fuel with cellulose, an abundant and inedible raw biomass. First, cellulose was selectively converted to 2,5-hexanedione in a separation yield of 71.4%. Subsequently, a mixture of C12 and C18 branched polycycloalkanes was directly obtained in a carbon yield of 74.6% by the aldol condensation-hydrogenation and hydrodeoxygenation reaction of 2,5-hexanedione and hydrogen over a dual-bed catalyst system. The polycycloalkane mixture obtained by this process has high density (0.88 g mL−1) and low freezing point (225 K). In real application, they can be used as advanced aviation fuel or additives to improve the volumetric heat values of conventional aviation fuels.

An engineered epoxide hydrolase from Vigna radiate (VrEH2M263N) shows near-perfect enantioconvergence in single enzyme mediated hydrolysis of racemic p-nitrostyrene oxide (pNSO). To explore industrial potential of the promising biocatalyst, we tried to immobilize the VrEH2 variant by covalently linking onto a commercially available amino resin ECR8405F. Then a 5-mL packed bed reactor filled with the immobilized VrEH2M263N was connected with macroporous resin NKA-11 for in situ product adsorption, and the product (R)-p-nitrophenyl glycol (pNPG) was harvested by methanol elution, with 91% isolated yield and 97% ee. The continuous reactor was operated stably for more than 100 h with a space time yield of 20 g⋅L−1⋅h−1. Subsequently, the β-blocker (R)-Nifenalol was prepared by chemically synthesized from (R)-pNPG, affording the product in an overall yield of 61.3% (1.5 g) and an enantiopurity of 99.9% ee after recrystallization.

A new route was developed for the synthesis of renewable decalin with cyclopentanone which can be derived from lignocellulose. It was found that 1,2,3,4,5,6,7,8-octahydronaphthalene could be selectively produced by the hydrogenation/dehydration/rearrangement of [1,1′-bi(cyclopentylidene)]-2-one (i.e. the self-aldol condensation product of cyclopentanone) over a dual-bed catalyst system. Among the investigated catalysts, the Ru/C and Amberlyst-15 resin exhibited the highest activities for the hydrogenation of [1,1′-bi(cyclopentylidene)]-2-one to [1,1′-bi(cyclopentan)]-2-ol and the dehydration/rearrangement of [1,1′-bi(cyclopentan)]-2-ol to 1,2,3,4,5,6,7,8-octahydronaphthalene, respectively. Using Ru/C and Amberlyst-15 resin as the first bed and the second bed catalysts, 1,2,3,4,5,6,7,8-octahydronaphthalene was directly produced in high carbon yield (83.7%) under mild conditions (393 K, 1 MPa). After being hydrogenated, the 1,2,3,4,5,6,7,8-octahydronaphthalene was converted to decalin which can be used as additive to improve the thermal stability and volumetric heat value of jet fuel.

1,2-Cyclohexanedicarboxylates, which are one of the most commonly used plasticizers in the poly(vinyl chloride) (PVC) industry, are generally prepared via the oxidation/esterification/hydrogenation...

For the first time, gasoline and jet fuel range C7–C8 cycloalkanes and aromatics were selectively synthesized by the alcoholysis of poly(ethylene terephthalate) (PET) waste, followed by solvent-free hydrogenation and hydrodeoxygenation (HDO). It was found that methanol is highly reactive for the alcoholysis of PET waste. In the absence of any catalyst, a high yield of dimethyl terephthalate (97.3%) was achieved under mild conditions (473 K, 3.5 h). Dimethyl terephthalate exists as a solid and can be automatically separated from methanol with a decrease in temperature. Subsequently, dimethyl terephthalate was liquefied to dimethyl cyclohexane-1,4-dicarboxylate by hydrogenation over noble metal catalysts. Among the investigated catalysts, Pt/C exhibited the highest activity. Finally, the dimethyl cyclohexane-1,4-dicarboxylate as obtained was further hydrodeoxygenated to C7–C8 cycloalkanes and aromatics that can be used as gasoline or additives to improve the densities (or volumetric heat value) and sealabilities of current bio-jet fuels. Bimetallic Ru–Cu/SiO2 was found to be a promising HDO catalyst. According to the characterization results, the excellent HDO performance of Ru–Cu/SiO2 can be explained by the formation of smaller Ru–Cu alloy particles during the catalyst preparation. In real applications, dimethyl cyclohexane-1,4-dicarboxylate can also be simultaneously hydrodeoxygenated with biomass derived oxygenates to produce jet fuel with a suitable content of cycloalkanes and aromatics.

International audience; This paper aims to develop a variable-node multiscale extended finite element method (V-XFEM) for dynamic fracture analysis of the linearly uncoupled and coupled physical phenomena in a compact formula. The general governing equations for the linearly uncoupled and coupled physical phenomena are presented in a compact form. The local mesh refinement technique for modeling cracks is used to improve the accuracy and efficiency, in which variable-node elements without modifying the system matrix or impose additional boundary conditions are taken to connect/link different scale elements. In addition, the time-dependent equations are solved by the unconditionally stable implicit Newmark time integration method, and the dynamic intensity factors (DIFs) are derived from the domain forms of the interaction integrals. Numerical results of the linearly elastic and piezoelectric problems show that V-XFEM is an efficient numerical approach to simulate the dynamic fracture problems of the linearly uncoupled and coupled physical phenomena.

We present ReasonBert, a pre-training method that augments language models with the ability to reason over long-range relations and multiple, possibly hybrid contexts. Unlike existing pre-training methods that only harvest learning signals from local contexts of naturally occurring texts, we propose a generalized notion of distant supervision to automatically connect multiple pieces of text and tables to create pre-training examples that require long-range reasoning. Different types of reasoning are simulated, including intersecting multiple pieces of evidence, bridging from one piece of evidence to another, and detecting unanswerable cases. We conduct a comprehensive evaluation on a variety of extractive question answering datasets ranging from single-hop to multi-hop and from text-only to table-only to hybrid that require various reasoning capabilities and show that ReasonBert achieves remarkable improvement over an array of strong baselines. Few-shot experiments further demonstrate that our pre-training method substantially improves sample efficiency., Accepted to EMNLP'2021. Our code and pre-trained models are available at https://github.com/sunlab-osu/ReasonBERT

International audience; Tribological behavior of graphene layers has been a focus of intensive research interest since its crystal lattice structure can be exploited to achieve incommensurate contact, leading to nearly zero friction, namely structural superlubricity. However, wrinkling undulations are omnipresent on graphene and difficult to be completely eliminated, which inevitably resists superlubricity in reality. Here, we explore how the presence of surface wrinkles affects nanotribological behavior of graphene sliding systems. Using a dimensionless parameter based on the topographic geometry, we propose a set of quantitative criteria permitting incommensurate-induced low friction even superlubricity to retain, despite the presence of surface wrinkles. Failing the criteria, achievement of superlubricity on wrinkled surface becomes implausible with unfavourable anisotropy and considerable friction. Besides, we examine the influence of diverse spatial topographic patterns such as stripe, checkerboard and herringbone on tribological behavior, and reveal that surface wrinkles can precisely tune the oscillating undulation of friction response. The proposed criteria may serve as an indicative reference that allows predicting the state of friction on practical, wrinkled graphene, and eventually assist the design of nanotribological systems with tunable friction.

The exploration of highly efficient processes to convert renewable biomass to fuels and value-added chemicals is stimulated by the energy and environment problems. Herein, we describe an innovative route for the production of methylcyclopentadiene (MCPD) with cellulose, involving the transformation of cellulose into 3-methylcyclopent-2-enone (MCP) and subsequent selective hydrodeoxygenation to MCPD over a zinc-molybdenum oxide catalyst. The excellent performance of the zinc-molybdenum oxide catalyst is attributed to the formation of ZnMoO3 species during the reduction of ZnMoO4. Experiments reveal that preferential interaction of ZnMoO3 sites with the C=O bond instead of C=C bond in vapor-phase hydrodeoxygenation of MCP leads to highly selective formations of MCPD (with a carbon yield of 70%)., Synthesis of methylcyclopentadiene (MCPD) with abundant biomass is appealing. Here the authors show that cellulose-derived 3-methylcyclopent-2-enone can be directly hydrodeoxygenated to MCPD over a partially reduced Zn-Mo oxide catalyst.

The effect of unloading stress levels on the unloading failure mechanism is explored from both macro- and microscopic perspectives by carrying out tests to load axial compression and unloa...

In this work, we investigate the data retention of programmable linear random-access memory (PLRAM), where the geometry and structure of memory cells have been modified to decouple the program/erase operation and gate oxide. Since PLRAM utilizes the bidirectional Fowler-Nordheim tunneling during program and erase operations through the sidewall tunneling oxide, the gate oxide does not receive the stress from the excessive program/erase cycles, resulting in a significant improvement of the data retention. Furthermore, it is confirmed that PLRAM can guarantee the stable 7-bit accuracy under high temperatures (>200°C), while a standard multi-level flash memory cell shows a significant degradation of multi-bit functionality due to the data loss and it ends up with a 4-bit accuracy in this study.

Environmental factors that drive carbon storage are often used as an explanation for alpine treeline formation. However, different tree species respond differently to environmental changes, which challenges our understanding of treeline formation and shifts. Therefore, we selected Picea jezoensis and Betula ermanii, the two treeline species naturally occurring in Changbai Mountain in China, and measured the concentration of non-structural carbohydrates (NSC), soluble sugars and starch in one-year-old leaves, shoots, stems and fine roots at different elevations. We found that compared with P. jezoensis, the NSC and soluble sugars concentrations of leaves and shoots of B. ermanii were higher than those of P. jezoensis, while the starch concentration of all the tissues were lower. Moreover, the concentration of NSC, soluble sugars and starch in the leaves of B. ermanii decreased with elevation. In addition, the starch concentration of B. ermanii shoots, stems and fine roots remained at a high level regardless of whether the soluble sugars concentration decreased. Whereas the concentrations of soluble sugars and starch in one-year-old leaves, shoots and stems of P. jezoensis responded similarly changes with elevation. These findings demonstrate that compared with P. jezoensis, B. ermanii has a higher soluble sugars/starch ratio, and its shoots, stems and fine roots actively store NSC to adapt to the harsh environment, which is one of the reasons that B. ermanii can be distributed at higher altitudes.

Proactive managements, such as the resistant and the adaptive treatments, have been proposed to cope with the uncertainties of future climates. However, quantifying the uncertainties of forest response to proactive managements is challenging. Korean pine is an ecologically and economically important tree species in the temperate forests of Northeast China. Its dominance has evidently decreased due to excessive harvesting in the past decades. Understanding the responses of Korean pine to proactive managements under the future climates is important. In this study, we evaluated the range of responses of Korean pine to proactive managements under Representative Concentration Pathway (RCP) 8.5 scenarios from four General Circulation Models (GCMs). We coupled an ecosystem process-based model, LINKAGES, and a forest landscape model, LANDIS PRO, to simulate scenarios of management and climate change combinations. Our results showed that the resistant and the adaptive treatment scenarios increased Korean pine importance (by 14.2% and 42.9% in importance value), dominance (biomass increased by 9.2% and 25.5%), and regeneration (abundance &lt, 10 years old increased by 286.6% and 841.2%) throughout the simulation. Results indicated that proactive managements promoted the adaptability of Korean pine to climate change. Our results showed that the variations of Korean pine response to climate change increased (ranging from 0% to 5.8% for importance value, 0% to 4.3% for biomass, and 0% to 85.4% for abundance) throughout the simulation across management scenarios. Our result showed that regeneration dictated the uncertainties of Korean pine response to climate change with a lag effect. We found that the effects of proactive managements were site-specific, which was probably influenced by the competition between Korean pine and the rare and protected broadleaf tree species. We also found that the adaptive treatment was more likely to prompt Korean pine to migrate into its suitable habitats and promoted it to better cope with climate change. Thus, the adaptive treatment is proposed for Korean pine restoration under future climates.

Valuable polyester monomers and plasticizers-1,4-cyclohexanedimethanol (CHDM), 1,4-cyclohexanedicarboxylic acid (CHDA), and 1,2-cyclohexanedicarboxylates-have been prepared by a new strategy. The synthetic processes involve a proline-catalyzed formal [3+1+2] cycloaddition of formaldehyde, crotonaldehyde, and acrylate (or fumarate). CHDM is produced after a subsequent hydrogenation step over a commercially available Cu/Zn/Al catalyst and a one-pot hydrogenation/oxidation/hydrolysis process yields CHDA, whereas 1,2-cyclohexanedicarboxylate is obtained by a Pd/C-catalyzed tandem decarbonylation/hydrogenation step.

For the first time, proline-based ionic liquids were reported as effective catalysts for the aldol condensation of angelica lactone with furfural, two platform compounds which were obtained by the hydrolysis–dehydration reactions of cellulose and hemicellulose. Among the investigated catalysts, a renewable ionic liquid that was prepared with biomass-derived choline and l-proline (denoted as ChPro) demonstrated the highest activity. Over the ChPro catalyst, 86% carbon yield of C10 oxygenate was obtained under mild conditions (353 K, 1 h). After being hydrogenated over the Pd/C catalyst and hydrodeoxygenated under the promotion of the Pd–Cu/SiO2, the aldol condensation product of angelica lactone with furfural was transmuted into C8–C10 alkanes within the carbon chain range of jet fuel and diesel. Compared with the Cu/SiO2 and Pd/SiO2, the bimetallic Pd–Cu/SiO2 demonstrated higher activity and/or selectivity to C8–C10 alkanes for the hydrodeoxygenation of hydrogenated aldol condensation product. According t...

One-dimensional (1D) Nd/Fe/polyamide 66 (Nd/Fe/PA66) three-layer coaxial nanocable arrays with high aspect ratio and highly anisotropic magnetization were successfully prepared via layer-by-layer deposition in the anodic aluminum oxide template. The morphology, chemical composition, and magnetic properties of Nd/Fe/PA66 nanocables were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and vibrating sample magnetometry . The effects of 1D nanocables on the magnetic properties of the assembled ordered arrays have been systematically investigated. The structural properties of these nanostructures are investigated as a function of the geometrical parameters. The magnetic anisotropy of Nd/Fe/PA66 nanocables has been significantly enhanced owing to the doped Nd that possesses a larger spin-orbital coupling and leads to a synergistic effect with Fe to enhance anisotropy energy.

Lignosulfonate-based renewable solid acids were first utilized as effective catalysts for fructose dehydration to produce 5-hydroxymethylfurfural (HMF). Among the investigated catalysts, the LF resin synthesized with formaldehyde and sodium lignosulfonate demonstrated the highest activity and good stability. Over it, ∼90% HMF carbon yield was reached at 393 K. On the basis of the characterization results of N2-physisorption, chemical titration, and microcalorimetric measurement of NH3 adsorption, the outstanding performance of LF resin should be interpreted by its higher acid strength and/or the synergistic effect of adjacent −SO3H, −COOH and phenolic −OH surface functional groups. We also explored the applicability of the LF resin for HMF production using other cheaper carbohydrates. Here, 73% HMF carbon yield was obtained from inulin hydrolysis/dehydration after the reaction was conducted over the LF resin at 393 K for 2.5 h.

A new two-step process was developed for the synthesis of high-density jet fuel range tricyclic alkanes with methyl benzaldehydes and cyclohexanone which can be derived from lignocellulose. In the first step, C14 oxygenates (i.e. 2-(2-methylbenzylidene)cyclohexanone or 2-(4-methylbenzylidene)cyclohexanone) were obtained by the solvent-free aldol condensation of 2-methyl benzaldehyde (or 4-methyl benzaldehyde) and cyclohexanone. Among the investigated catalysts, the EAOAc ionic liquid (a renewable catalyst which was prepared with ethanolamine and acetic acid) exhibited the highest activity and good stability for this reaction. Over it, high carbon yields (∼85%) of C14 oxygenates were achieved under mild reaction conditions (353 K, 6 h). In the second step, the C14 oxygenates were selectively converted into 1-methyldodecahydro-1H-fluorene and 3-methyldodecahydro-1H-fluorene by the aqueous phase hydrodeoxygenation (APHDO) over a commercial Pd/C catalyst. According to our measurement, the 1-methyldodecahydro-1H-fluorene and 3-methyldodecahydro-1H-fluorene as obtained have high densities (0.99 g mL−1 and 0.96 g mL−1, respectively, at 298 K). As a potential application, they can be used as additives to improve the volumetric heat values of the current bio-jet fuels.

For the first time, 1,​1,​3-​trimethyl-cyclohexane (a jet fuel range cycloalkane) was synthesized by coupling the aqueous phase reforming (APR) of glycerol and the hydrodeoxygenation (HDO) of isophorone which can be obtained from lignocellulose. Among the investigated catalysts, Pt/Al 2 O 3 was found to be the most active for the production of 1,​1,​3-​trimethyl-cyclohexane with the hydrogen which was in-situ generated by the APR of glycerol. Over it, high carbon yield (67.0%) of 1,​1,​3-​trimethyl-cyclohexane can be achieved at 533 K in the absence of external hydrogen. The excellent performance of Pt/Al 2 O 3 catalyst can be explained because Pt is highly active for both APR and HDO reactions. Besides glycerol, many other lignocellulose derived polylols (such as ethylene glycol, xylitol and sorbitol) and methanol can also be used as renewable hydrogen source for the HDO of isophorone. As a potential application, the 1,​1,​3-​trimethyl-cyclohexane as obtained can be blended into the conventional jet fuels to improve their volumetric heat values.

La–doped Ni/Al2O3 catalysts were synthesised with a modified wetness impregnation method. The addition of La promoted the reduction of Ni oxides and improved the dispersion. High catalytic activity and selectivity were obtained in the selective hydrogenation of styrene using these catalysts. The catalyst with a La content of 0.5 wt% (Ni–La/Al2O3-0.5) exhibited the highest styrene conversion (100%) and selectivity (>99%).

In the present paper, a novel difluoroboron dipyrromethene-based (BODIPY) fluorescent probe with a conjugated hydrazone group, named BDBH, was developed for the detection of F− with high selectivity and sensitivity. After addition of tetrabutylammonium fluoride (TBAF) into a BDBH solution, the fluorescence was “turned on”, which displayed an 80-fold increasement of emission intensity. The wavelengths of excitation and emission were 518 nm and 613 nm respectively, which were free from the background interference. The titration of 1H NMR (Nuclear Magnetic Resonance) indicated that the interaction involved hydrogen-bonding formation between the acidic H of –NH–C O group and F− at low concentration and deprotonation of N–H group at increasing concentration of fluoride. The theoretical calculations verified that once F− interacted with BDBH, the planarity and conjugation of BDBH enhanced, which resulted in a strong fluorescence emission at 613 nm. Furthermore, confocal fluorescence images of BDBH-incubated HeLa cells verified its potential application as an “off-on” sensor to monitor F− in living cells.

Esomeprazole, the S-enantiomer of omeprazole, is the best-selling proton pump inhibitor. In our previous work, a mutant of cyclohexanone monooxygenase from the Acinetobacter calcoaceticus (named AcCHMO-M6) was successfully obtained through protein engineering which could catalyze the oxidation of omeprazole sulfide. However, its practical application is still hindered by the poor thermostability, especially in the up-scaled reaction process. In this work, site mutagenesis based on consensus analysis and directed evolution were used to engineer this enzyme in order to improve the stability of AcCHMO-M6. The half-lives of the resultant mutants AcCHMO-M9 (F29L/R444E) and AcCHMO-M10 (F29L/R444E/A145S/G430T) at 40 °C were increased from 2.2 h to 8.5 h and 5.9 h respectively, while the corresponding Tm values were increased by 7 °C and 5.3 °C in comparison to AcCHMO-M6. The specific activity of AcCHMO-M9 was comparable to that of AcCHMO-M6, and the specific activity of AcCHMO-M10 was about 4-fold that of AcCHMO-M6. The AcCHMO-M10 catalyzed sulfide oxidation reaction reached 100% conversion after 16 hours at 30 °C, in contrast to 39.4% conversion in the case of AcCHMO-M6. These results show that the potential of this thioether monooxygenase can be significantly improved by protein engineering.

Single metal atoms and metal clusters have attracted much attention because of their high dispersity, special electronic structures, and uniformity of active sites as heterogeneous catalysts, but it is still challenging to generate stable single atoms and clusters with high metal loadings. Supports play a crucial role in determining particle morphology and maintaining dispersion. Herein we synthesize an amorphous alumina with 29% coordinatively unsaturated pentacoordinate Al3+ (Al3+penta) sites, which can anchor atomically dispersed Ru species with 1 wt % loading. Strong interactions between Ru and Al3+penta centers were detected, resulting in distinct Ru geometric and electronic features. When used in benzene hydrogenation reaction, fairly high specific activity (TOF = 5180 h–1) were obtained. The high catalytic performance is considered closely correlated with the high utilization of special Ru active sites.

A route was developed for the synthesis of diesel and jet fuel range C9 and C10 alkanes with furfural and angelica lactone, which can be obtained from hemicellulose and cellulose. It was found that angelica lactone is more reactive than levulinic acid or its other derivates in the aldol condensation with furfural. Among the investigated catalysts, Mn2O3 was found to be the most active and was very stable for the aldol condensation of furfural and angelica lactone. Over Mn2O3, a high carbon yield of C10 oxygenates (about 96%) can be achieved by the aldol condensation of furfural and angelica lactone under mild conditions (353 K, 4 h). By the hydrogenation and hydrodeoxygenation of the aldol condensation product over the Pd/C and Pd-FeOx/SiO2 catalysts, high carbon yields (∼96%) of C9 and C10 alkanes were obtained.

The selective dehydration of pinacol derivatives to branched 1,3-dienes is extremely challenging because of the predominance of pinacol rearrangement. Herein, we successfully achieve this goal by employing a recyclable solid acid/ionic liquid catalyst system. The dehydration of alkyl- and cycloalkyl-derived diols in an Amberlyst-15/[Emim]Cl system afforded the corresponding 1,3-dienes in good yields, while a Nafion/[Emim]Cl system was demonstrated to be a better catalyst system for the dehydration of aryl-substituted substrates. Our protocol features straightforward and simple access to branched 1,3-dienes, high chemoselectivity, a recyclable catalyst system, a facile separation of dienes just by decantation, and a broad substrate scope.

Biocatalysts originating from Badamu (Prunus communis) have been applied to catalyze the asymmetric synthesis of (R)-4-methylsulfanylmandelonitrile, a key building block of thiamphenicol and florfenicol. Here, four hydroxynitrile lyase (HNL) isozymes from Badamu were cloned and heterologously expressed in Pichia pastoris. The biochemical properties and catalytic performances of these isozymes were comprehensively explored to evaluate their efficiency and selectivity in asymmetric synthesis. Among then, PcHNL5 was identified with outstanding activity and enantioselectivity in asymmetric hydrocyanation. Under the optimized mild biphasic reaction conditions, seventeen prochiral aromatic aldehydes were converted to valuable chiral cyanohydrins with good yields (up to 94%) and excellent optical purities (up to >99.9% ee), which provide a facile access to numerous chiral amino alcohols, hypoglycemic agents, angiotension converting enzyme (ACE) inhibitors and β-blockers. This work therefore underlines the importance of discovering the most potent biocatalyst among a group of isozymes for converting unnatural substrates into value-added products.

Using a total of 297 segmented sections, we reconstructed the three-dimensional (3D) structure of pure iron and obtained the largest dataset of 16254 3D complete grains reported to date. The mean values of equivalent sphere radius and face number of pure iron were observed to be consistent with those of Monte Carlo simulated grains, phase-field simulated grains, Ti-alloy grains, and Ni-based super alloy grains. In this work, by finding a balance between automatic methods and manual refinement, we developed an interactive segmentation method to segment serial sections accurately in the reconstruction of the 3D microstructure; this approach can save time as well as substantially eliminate errors. The segmentation process comprises four operations: image preprocessing, breakpoint detection based on mathematical morphology analysis, optimized automatic connection of the breakpoints, and manual refinement by artificial evaluation.

A series of renewable C9 -C12 triketones with repeating [COCH2 CH2 ] units were synthesized in high carbon yields (ca. 90 %) by the aqueous-phase hydrogenation of the aldol-condensation products of 5-hydroxylmethylfurfural (HMF) and ketones over an Au/TiO2 catalyst. Compared with the reported routes, this new route has many advantages such as being environmentally friendly, having fewer steps, using a cheaper and reusable catalyst, etc. The triketones as obtained can be used as feedstocks in the production of conducting or semi-conducting polymers. Through a solvent-free intramolecular aldol condensation over solid-base catalysts, the triketones were selectively converted to diketones, which can be used as intermediates in the synthesis of useful chemicals or polymers. As another application, the tri- and diketones can also be utilized as precursors for the synthesis of jet-fuel range branched cycloalkanes with low freezing points (224-248 K) and high densities (ca. 0.81 g mL-1 ).

For the first time, the Pd/SiO2 which was modified by FeOx species (Pd-FeOx/SiO2) was reported as an active catalyst for the solvent-free hydrodeoxygenation (HDO) of the aldol condensation product of furfural and methyl-isobutylketone (MIBK). The presence of iron species not only restrains the C C cleavage (decarbonylation and retro-aldol condensation) over the Pd/SiO2 catalyst but also decreases the hydrogen pressure which is needed for the total HDO of aldol condensation product over the Pd/SiO2 catalyst. Compared with the Pd/SiO2 catalyst, the Pd-FeOx/SiO2 catalyst also exhibited higher activity for the HDO of other furan compounds under atmospheric pressure. Over the 5%Pd-2.5%FeOx/SiO2 catalyst, complete conversion of feedstocks and high carbon yields of jet fuel range alkanes (87–94%) can be achieved by the atmospheric HDO of a series of furan compounds at 623 K or 573 K. From the results of XRD, STEM, CO chemisorption, FT-IR, EXAFS, H2-TPR, in-situ XPS and quasi-in-situ Mossbauer spectra, it was noticed that the modification of iron species decreases the coordination number of Pd–Pd on the Pd/SiO2 catalyst, which may restrain the decarbonylation during the HDO process. The presence of Pd promotes the reduction of iron species and the generation of Pd-Fe alloy. Both effects may be the reasons why the Pd-FeOx/SiO2 catalyst is more active than Pd/SiO2 in the solvent-free HDO of furan compounds under atmospheric pressure.

1-(3-Cyclopentyl)cyclopentyl-2-cyclopentylcyclopentane, a renewable high-density fuel, was first produced in a high overall carbon yield (∼70%) with cyclopenanone that can be derived from hemicellulose. The synthetic route used in this work contains three steps. In the first step, 2-cyclopentyl cyclopentanone was synthesized for the first time by a one-pot reaction of cyclopentanone and hydrogen under the catalysis of Raney metal and alkali hydroxides. Over the optimized catalyst (Raney cobalt + KOH), a high carbon yield (83.3%) of 2-cyclopentyl cyclopentanone was achieved at 353 K. In the second step, 2-cyclopentyl-5-(2-cyclopentylcyclopentylidene)cyclopentanone was produced in a high carbon yield (95.4%) by the solvent-free self-aldol condensation of 2-cyclopentyl cyclopentanone under the vacuum conditions. In the third step, the 2-cyclopentyl-5-(2-cyclopentylcyclopentylidene)cyclopentanone was hydrodeoxygenated over the Ni-SiO2 catalyst under solvent-free conditions. High carbon yields of 1-(3-cyclopen...

For the first time, a renewable acidic resin which was prepared by one-step condensation/sulfation of sodium sulfite, cyclopentanone and formaldehyde followed by ion-exchanging was found to be a highly active and stable catalyst for the production of 5-hydroxymethylfurfural (HMF) by the dehydration of fructose and inulin.

Herein, we report an unprecedented and sustainable route to synthesize pyromellitic acid (PMA), a monomer of polyimide, with pinacol and diethyl maleate which can be derived from lignocellulose. Analogously, a sustainable route to trimellitic acid (TMA) was also developed using pinacol and acrylate as the feedstocks.

Ecological floating bed (EFB) has become the preferred technology due to its reputation of green economy, convenience, and efficiency in treating eutrophic landscape water. Based on the statistical analysis of abundant literatures, this paper systematically summarizes the component elements, design parameters, purification mechanism, purification ability, strengthening methods and the correlations among various parameters of EFB, and points out some issues existing in the current research and applications. The results show that the coverage of 5% ~ 38% and water depth of 60 ~ 110 cm should be recommended for EFB design. The microbial transformation-sedimentation contributes mostly to the removal of pollutant, leading to the contribution rate of 51.9% ± 26.4% to nitrogen (N) removal and 50.8% ± 20.4% to phosphorus (P) removal in water respectively. Meanwhile, the average purification abilities of EFB for carbon (C), N and P in water are 4.59 ± 3.82, 0.43 ± 0.35 and 0.04 ± 0.04 g m−2 d-1 respectively. The purification effect is relatively superior when the initial concentration of C, N and P in water is close to C: N: P = 115: 11: 1. In order to enhance the EFB purification efficiency, the methods of artificial aeration, biological chain extension, functional filler introduction, and composite EFB construction can be used. Furthermore, the purification ability of EFB per unit area is correlated positively with water temperature and initial pollutant concentration (r ≥ 0.577, p

Global air temperature has increased and continues to increase, especially in high latitude and high altitude areas, which may affect plant resource physiology and thus plant growth and productivity. The resource remobilization efficiency of plants in response to global warming is, however, still poorly understood. We thus assessed end-season resource remobilization from leaves to woody tissues in deciduous Betula ermanii Cham. trees grown along an elevational gradient ranging from 1700 m to 2187 m a.s.l. on Changbai Mountain, northeastern China. We hypothesized that end-season resource remobilization efficiency from leaves to storage tissues increases with increasing elevation or decreasing temperature. To test this hypothesis, concentrations of non-structural carbohydrates (NSCs), nitrogen (N), phosphorus (P), and potassium (K) during peak shoot growth (July) were compared with those at the end of growing season (September on Changbai Mt.) for each tissue type. To avoid leaf phenological effects on parameters, fallen leaves were collected at the end-season. Except for July-shoot NSC and July-leaf K, tissue concentrations of NSC, N, P, and K did not decrease with increasing elevation for both July and September. We found that the end-season leaf-to-wood reallocation efficiency decreased with increasing elevation. This lower reallocation efficiency may result in resource limitation in high-elevation trees. Future warming may promote leaf-to-wood resource reallocation, leading to upward shift of forests to higher elevations. The NSC, N, P, and K accumulated in stems and roots but not in shoots, especially in trees grown close to or at their upper limit, indicating that stems and roots of deciduous trees are the most important storage tissues over winter. Our results contribute to better understand the resource-related ecophysiological mechanisms for treeline formation, and vice versa, to better predict forest dynamics at high elevations in response to global warming. Our study provides resource-related ecophysiological knowledge for developing management strategies for high elevation forests in a rapidly warming world.

In China, most rural areas lack specific sewage discharge standards. Even though China governments proposed a series of local standards, the most of the existing China's rural sewage discharge standards are still similar to urban discharge standards. This research analyses comprehensively the data of rural sewage discharge standards in the 31 provinces and cities in China in terms of grade and indicator, and forms a structural framework for the formulation and revised standards in rural areas of China. In the formulation, we use 2 components, end-use and environmental capacity, to reflect local characteristics of the grades and indicators, and also propose the methods of combining discharge standards with relevant water quality standards to save energy. And we also use the mathematical model to illustrate environmental capacity in different regions. The paper shows the great potential in guiding the design of discharge standards formulation and revision for rural wastewater treatment in China and other developing countries as well.

Decalin is the main component of JP-900, a thermally stable and high-energy density jet fuel. Decalin is also an important component of advanced jet fuels. Cyclopentanol is a platform compound that can be derived from lignocellulose. In this work, a mixture of C10 and C15 polycycloalkanes (with decalin as the major component) was first synthesized by the oligomerization/rearrangement of cyclopentene from the dehydration of cyclopentanol, followed by hydrogenation. Among the investigated catalysts, Amberlyst-36 resin demonstrated the highest activity and excellent stability for cyclopentanol dehydration and cyclopentene oligomerization/rearrangement. The influences of reaction temperature and reaction time on the catalytic performances of Amberlyst-36 resin for both reactions were investigated. Under the optimum conditions, 84.0% carbon yield of cyclopentene was obtained from cyclopentanol dehydration, and 74.2% carbon yield of C10 and C15 polycycloalkenes was achieved by the oligomerization/rearrangement ...

Microseismic signal is inevitably mixed with non-stationary random noise in the process of acquisition, which is difficult to be separated from non-stationary random noise by using the traditional methods of linear filtering and spectrum analysis. Thus a suppressing method of non-stationary random noise is proposed. It firstly conducts the multi-scale decomposition of microseismic signal containing noises based on ensemble empirical mode decomposition (EEMD). Several components of Intrinsic Mode Functions (IMFs) are obtained and they are arranged in descending order according to their frequencies. In order to accurately identify the signals and noises in these IMF components and compare the normal microseismic signals with noises, the quantity of permutation entropy is introduced to describe the characteristics of normal microseismic signal. The threshold value of permutation entropy is used to extract the IMF components conforming to the characteristics of microseismic signal. These IMF components are reconstructed to suppress the noise. Through simulation and the test for the practical microseismic monitoring data, it is indicated that the method has a better treatment effect for non-stationary random noise in microseismic signal.