Boosting Activity and Selectivity of UiO-66 through Acidity/Alkalinity Functionalization in Dimethyl Carbonate Catalysis.

The acid-base properties of supports have an enormous impact on catalytic reactions to regulate the selectivity and activity of supported catalysts. Herein, a train of Pd-X-UiO-66 (X = NO2 , NH2 , and CH3 ) catalysts with different acidity/alkalinity functional groups and encapsulated Pd(II) species is first developed, whose activities in dimethyl carbonate (DMC) catalysis are then investigated in details. Thereinto, the Pd-NO2 -UiO-66 catalyst with acidity functionalization exhibits the best catalytic behavior: the DMC selectivity stemmed from methyl nitrite (MN) is up to 68%, the conversion of CO is 73.4%. The obtained experimental results demonstrate that the NO2 group not only affected the interaction between X-UiO-66 and Pd(II) active sites but also play an indispensable role in the adsorption and activation of MN and CO, which remarkably promote the formation of the COOCH3 * intermediate and DMC product.

[Research progress on genus Clinopodium].

The plants of genus Clinopodium are perennial herbs of Labiatae, which are widely distributed in the world and have a promising medicinal value. Modern researches have shown flavonoids, triterpenoid saponins, terpene glycosides, terpenoids, volatile oils and phenylpropanoids are the main compounds in the plants, presenting various pharmacological effects such as hemostasis, anti-bacteria, anti-inflammation, immunoregulation, reducing blood glucose, antioxidation, and anti-tumor effects. The preparations made of those plants are mainly used for treatment of various bleeding diseases in clinical application. In this review, we systematically summarized the research progress on taxonomy, resource distribution, chemical compositions, pharmacological activities, and clinical application of the medicinal plants of genus Clinopodium. This review provides references and scientific basis for further research and development of genus Clinopodium.

Multiple rice microRNAs are involved in immunity against the blast fungus Magnaporthe oryzae.

MicroRNAs (miRNAs) are indispensable regulators for development and defense in eukaryotes. However, the miRNA species have not been explored for rice (Oryza sativa) immunity against the blast fungus Magnaporthe oryzae, the most devastating fungal pathogen in rice production worldwide. Here, by deep sequencing small RNA libraries from susceptible and resistant lines in normal conditions and upon M. oryzae infection, we identified a group of known rice miRNAs that were differentially expressed upon M. oryzae infection. They were further classified into three classes based on their expression patterns in the susceptible japonica line Lijiangxin Tuan Hegu and in the resistant line International Rice Blast Line Pyricularia-Kanto51-m-Tsuyuake that contains a single resistance gene locus, Pyricularia-Kanto 51-m (Pikm), within the Lijiangxin Tuan Hegu background. RNA-blot assay of nine of them confirmed sequencing results. Real-time reverse transcription-polymerase chain reaction assay showed that the expression of some target genes was negatively correlated with the expression of miRNAs. Moreover, transgenic rice plants overexpressing miR160a and miR398b displayed enhanced resistance to M. oryzae, as demonstrated by decreased fungal growth, increased hydrogen peroxide accumulation at the infection site, and up-regulated expression of defense-related genes. Taken together, our data indicate that miRNAs are involved in rice immunity against M. oryzae and that overexpression of miR160a or miR398b can enhance rice resistance to the disease.

Pig farm biogas slurry can effectively reduce the pH of saline-alkali soils.

Pig farm biogas slurry is being increasingly used as a potent organic fertilizer for sustainable agriculture under circular economy. However, the effect of biogas slurry on soil pH is currently controversial, and the underlying mechanisms especially in saline-alkali soils are not well understood. A saline-alkali soil (pH = 9.2, EC = 2.0 ms/cm) was selected for soil column (0-50 cm) experiments with (BS) and without (CK) addition of pig farm biogas slurry to investigate the soil pH change and its driving factors. Our results show that the soil pH under CK ranged between 9.1 and 9.5 across different soil depths. Compared to CK, the BS-treated soil had lower pH at 0-20 cm depth and higher pH at 20-30 cm depth (P < 0.01). The soil NH4+-N concentrations were negatively correlated with pH values under BS (P < 0.01), indicating that the oxidation of ammonium mainly contributed to the decrease of soil pH. Interestingly, the anions, such as Cl-, SO42- and NO3-, were accumulated in the topsoil (0-20 cm) under BS, resulting in the changed correlations of these anions with Na+ when compared to the control. FT-IR and 13C-NMR spectra uncovered that carboxyl, amide C, and total alkyl C groups may be responsible for reducing pH of the saline-alkali soil tested. The soil surface morphology confirmed a much tighter granular aggregate microstructure when mixing the biogas slurry with the soil. Overall, we concluded that from the perspective of soil pH, the utilization of biogas slurry for improving saline-alkali soil is feasible and sustainable.

A Spatial-Temporal Video Quality Assessment Method via Comprehensive HVS Simulation.

The quality of videos is the primary concern of video service providers. Built upon deep neural networks, video quality assessment (VQA) has rapidly progressed. Although existing works have introduced the knowledge of the human visual system (HVS) into VQA, there are still some limitations that hinder the full exploitation of HVS, including incomplete modeling with few HVS characteristics and insufficient connection among these characteristics. In this article, we present a novel spatial-temporal VQA method termed HVS-5M, wherein we design five modules to simulate five characteristics of HVS and create a bioinspired connection among these modules in a cooperative manner. Specifically, on the side of the spatial domain, the visual saliency module first extracts a saliency map. Then, the content-dependency and the edge masking modules extract the content and edge features, respectively, which are both weighted by the saliency map to highlight those regions that human beings may be interested in. On the other side of the temporal domain, the motion perception module extracts the dynamic temporal features. Besides, the temporal hysteresis module simulates the memory mechanism of human beings and comprehensively evaluates the video quality according to the fusion features from the spatial and temporal domains. Extensive experiments show that our HVS-5M outperforms the state-of-the-art VQA methods. Ablation studies are further conducted to verify the effectiveness of each module toward the proposed method. The source code is available at https://github.com/GZHU-DVL/HVS-5M.

Emerging catalysts for the ambient synthesis of ethylene glycol from CO2 and its derivatives.

Ethylene glycol (EG), a useful chemical raw material, has been widely applied in many aspects of modern society. The conventional preparation of ethylene glycol mainly uses the petroleum route at high temperatures and pressure. More and more approaches have been developed to synthesize EG from CO2 and its derivatives under mild conditions. In this review, the ambient synthesis of EG from thermocatalysis, photocatalysis, and electrocatalysis is highlighted. The coal-to-ethylene glycol technology, one of the typical thermal catalysis routes for EG preparation, is relatively mature. However, it still faces some problems to be solved in industrialization. The recent progress in the development of coal-to-ethylene glycol technology is introduced. The main focus is on how to realize the preparation of EG under mild conditions. The strategies include doping promoters, modification of supports, design of catalysts with special structures, etc. Furthermore, the emerging technological progress of photocatalytic and electrocatalytic ethylene glycol synthesis under ambient conditions is introduced. Compared with the thermal catalytic reaction, the reaction conditions are milder. However, there are still many problems in large-scale production. Finally, we propose future development issues and related prospects for the ambient synthesis of EG using different catalytic routes.

[Short fusion and long fusion for degenerative lumbar scoliosis with lumbar stenosis].

OBJECTIVE: To explore the indications, surgical techniques and prognostic factors of short fusion versus long fusion for elder patients with degenerative lumbar scoliosis. METHODS: Thirty-eight patients undergoing different kinds of surgical procedures for lumbar spinal scoliosis between June 2005 and October 2010 were recruited for this retrospective study. The mean patient age at surgery was 64.2 years (range: 61 - 75). The short fusion group included 13 patients and the long fusion group 25 patients. RESULTS: There were a variety of treatment methods of degenerative scoliosis based on the symptomatology and radiological measurements of scoliosis and stenosis. Thirty-eight patients were followed up for an average of 37 months. The number of fused levels was 2.8 ± 0.7 segments in the short fusion group versus 5.1 ± 1.4 in the long fusion group. The average preoperative Cobb angle was 18.6° (range: 12 - 27) in the short fusion group versus 33.5° (range: 3 - 42) in the long fusion group. The correction of Cobb angle averaged 40% in the short fusion group versus 67% in the long fusion group. Clinical symptoms and functional tolerance for daily activities improved postoperatively. Radiographic evaluations showed reduced deformity on the frontal and sagittal planes. There were no infections, pseudoarthrosis, instrument-related failures or reoperations. CONCLUSIONS: Long segment fusion is superior to its short segment counterpart in correcting scoliotic curvature and coronal imbalance and improving rotational subluxation of apical vertebra. Careful perioperative preparation is essential in the treatment of elder patients with lumbar spinal scoliosis.

Ambient-pressure synthesis of ethylene glycol catalyzed by C60-buffered Cu/SiO2.

Bulk chemicals such as ethylene glycol (EG) can be industrially synthesized from either ethylene or syngas, but the latter undergoes a bottleneck reaction and requires high hydrogen pressures. We show that fullerene (exemplified by C60) can act as an electron buffer for a copper-silica catalyst (Cu/SiO2). Hydrogenation of dimethyl oxalate over a C60-Cu/SiO2 catalyst at ambient pressure and temperatures of 180° to 190°C had an EG yield of up to 98 ± 1%. In a kilogram-scale reaction, no deactivation of the catalyst was seen after 1000 hours. This mild route for the final step toward EG can be combined with the already-industrialized ambient reaction from syngas to the intermediate of dimethyl oxalate.

Multifunctional homochiral lanthanide camphorates with mixed achiral terephthalate ligands.

Seven homochiral lanthanide camphorates with mixed achiral terephthalate ligands, namely, {Ln(2)(cam)(2)(bdc)(H(2)O)(2)}·DMF [Ln = Sm (1), Eu (2), Gd (3), Tb (4), Dy (5), Ho (6), Er (7); d-H(2)cam = d-(+)-camphoric acid; H(2)bdc = 1,4-benzenedicarboxylic acid; DMF = N,N'-dimethylformamide], have been solvothermally synthesized. Single-crystal X-ray diffraction analyses reveal that compounds 1-7 are isostructural and crystallize in orthorhombic, chiral space group P2(1)2(1)2(1). These structures feature three-dimensional open frameworks based on rodlike [Ln(2)(OCO)(6)(H(2)O)(2)](n) secondary building units, with the guest DMF molecules occupying the void space of the host {Ln(2)(cam)(3)(bdc)(H(2)O)(2)} framework. The photophysical and magnetic properties of some of these complexes have been investigated. Notably, the terbium compound 4 is highly emissive with a quantum yield of 63.68%. Additionally, thermogravimetric analyses, variable-temperature IR spectroscopy, and powder X-ray diffraction of 2 as a representative were performed to determine its thermal stability, which indicates that the framework still remains intact until 300 °C.

Breaking the mirror: pH-controlled chirality generation from a meso ligand to a racemic ligand.

To study the conversion from a meso form to a racemic form of tetrahydrofurantetracarboxylic acid (H(4)L), seven novel coordination polymers were synthesized by the hydrothermal reaction of Zn(NO(3))(2)6 H(2)O with (2S,3S,4R,5R)-H(4)L in the presence of 1,10-phenanthroline (phen), 2,2'-bipyridine (2,2'-bpy), or 4,4'-bipyridine (4,4'-bpy): [Zn(2){(2S,3S,4R,5R)-L}(phen)(2)(H(2)O)]2 H(2)O (1), [Zn(4){(2S,3R,4R,5R)-L}{(2S,3S,4S,5R)-L}(phen)(2)(H(2)O)(2)] (2), [Zn(2){(2S,3S,4R,5R)-L}(H(2)O)(2)]H(2)O (3), [Zn(4){(2S,3R,4R,5R)-L}{(2S,3S,4S,5R)-L} (2,2'-bpy)(2)(H(2)O)(2)]2 H(2)O (4), [Zn(2) {(2S,3S,4R,5R)-L}(2,2'-bpy)(H(2)O)] (5), [Zn(4){(2S,3R,4R,5R)-L}{(2S,3S,4S,5R)-L} (4,4'-bpy)(2)(H(2)O)(2)] (6), and [Zn(2) {(2S,3S,4R,5R)-L}(4,4'-bpy)(H(2)O)] 2 H(2)O (7). These complexes were obtained by control of the pH values of reaction mixtures, with an initial of pH 2.0 for 1, 2.5 for 2, 4, and 6, and 4.5 for 3, 5, and 7, respectively. The expected configuration conversion has been successfully realized during the formation of 2, 4, and 6, and the enantiomers of L, (2S,3R,4R,5R)-L and (2S,3S,4S,5R)-L, are trapped in them, whereas L ligands in the other four complexes retain the original meso form, which indicates that such a conversion is possibly pH controlled. Acid-catalyzed enol-keto tautomerism has been introduced to explain the mechanism of this conversion. Complex 1 features a simple 1D metal-L chain that is extended into a 3D supramolecular structure by pi-pi packing interactions between phen ligands and hydrogen bonds. Complex 2 has 2D racemic layers that consist of centrosymmetric bimetallic units, and a final 3D supramolecular framework is formed by the interlinking of these layers through pi-pi packing interactions of phen. Complex 3 is a 3D metal-organic framework (MOF) involving meso-L ligands, which can be regarded as (4,6)-connected nets with vertex symbol (4(5).6)(4(7).6(8)). Complexes 4 and 5 contain 2D racemic layers and (6,3)-honeycomb layers, respectively, both of which are combined into 3D supramolecular structures through pi-pi packing interactions of 2,2'-bpy. The structure of complex 6 is a 2D network formed by 4,4'-bpy bridging 1D tubes, which consist of metal atoms and enantiomers of L. These layers are connected through hydrogen bonds to give the final 3D porous supramolecular framework of 6. Complex 7 is a 3D MOF with novel (3,4,5)-connected (6(3))(4(2).6(4))(4(2).6(6).8(2)) topology. The thermal stability of these compounds was also investigated.

Ag(I)-mediated in situ dehydrogenative coupling of 3-amino-1,2,4-triazole into 3,3'-azobis(1,2,4-triazole) in Cd(II) coordination polymers.

Ag(I)-mediated in situ generation of 3,3'-azobis(1,2,4-triazole) (AzTAZ) from 3-amino-1,2,4-triazole (AmTAZ) through dehydrogenative coupling has been realized during the crystallization process of two Cd(II) coordination polymers with novel topological architectures: a (3, 4, 5)-connected (4 x 6(2))(2)(4 x 6(7) x 8(2))(2)(6(5) x 10) net for [Cd(2)(AmTAZ)(2)(AzTAZ)](n) (1) and a 4-connected (6(2) x 8(4))(6(4) x 8(2))(6(5) x 8)(2) net for [Cd(AzTAZ)(2)(H(2)O)](n) (2), whereas AmTAZ retains its original form in a heterometallic complex, [Ag(2)Cd(AmTAZ)(4)](n) (3).

Temperature-controlled syntheses of substituted 1,2,4-triazolelead(II) complexes: active lone pair and N-H...X (X = Cl, Br, I) hydrogen bonds.

Three isomorphous lead(II) complexes with a new {N(3)SX}-coordinated (X = Cl, Br, I) mode have been synthesized and characterized by X-ray diffraction. The structural analyses reveal that the coordination environment around the center metal is distinctly influenced by the stereochemical 6s(2) lone pair and N-H...X hydrogen bonds. Additionally, doubly deprotonated trzS(2-) (HtrzSH = 1,2,4-triazole-3-thiol) generated in situ via deamination and dehydrazination of ahtrzS(-) (ahtrzSH = 4-amino-3-hydrazino-5-mercapto-1,2,4-triazole) was first observed in a semiconducting three-dimensional coordination network at higher reaction temperature.

Synthesis, structure, and luminescent properties of hybrid inorganic-organic framework materials formed by lead aromatic carboxylates: inorganic connectivity variation from 0D to 3D.

The hydro(solvo)thermal reactions of Pb(OAc)(2).3H(2)O with the aromatic carboxylic ligands 1,3,5-benzenetricarboxylic and 1,4-, 1,2-, and 1,3-benzenedicarboxylic acids (1,3,5-H(3)BTC; 1,4-, 1,2-, and 1,3-H(2)BDC) have yielded a family of inorganic-organic framework materials: [Pb(2)(1,3,5-BTC)(mu(3)-OH)(H(2)O)](n) (Iota), [NaPb(1,3,5-BTC)(H(2)O)](n) (IotaIota), [Pb(1,4-BDC)](n) (IotaIotaIota), [Pb(5)(1,2-BDC)(4)(OAc)(2)](n) (IV), and {[Pb(5)(1,3-BDC)(5)(H(2)O)(2)](2).H(2)O}(n) (V). These complexes have been characterized by means of single-crystal X-ray diffraction, X-ray powder diffraction, thermogravimetric analysis-mass spectrometry, and photoluminescence spectra. They are all three-dimensional structures except for two-dimensional IV. Topology analysis reveals that complexes I an V represent rare (4,8)-connected flu and (3,4)-connected zeolite-like nets, respectively. The five complexes exhibit diverse inorganic connectivity, including a 0D Pb(4)O(16) cluster for I, a 1D Pb-O-Pb chain for II, a 2D Pb-O-Pb network for III and IV, and an unprecedented 3D Pb-O-Pb framework for V. And the diversity in inorganic arrays leads to differences in luminescent properties of these complexes.

Impact of cross-correlated sine-Wiener noises in the gene transcriptional regulatory system.

We studied fluctuation-induced switching processes in the gene transcriptional regulatory system under cross-correlated sine-Wiener (CCSW) noises. It is numerically demonstrated that the increase of the multiplicative noise intensity A and cross-correlation time τ in CCSW noises can reduce the concentration of the TF-A monomer and switch to an "off" state. In addition, when the cross-correlation time τ is small, the increase of the additive noise intensity B leads to a switch of the process from "off"→"on". Simultaneously, the increase of the cross-correlation intensity λ of CCSW noises contributes to maintaining the current state. When the cross-correlation time is large, the high concentration state has two peaks and the stationary probability distribution presents a three-peak structure.

CO2 hydrogenation to high-value products via heterogeneous catalysis.

Recently, carbon dioxide capture and conversion, along with hydrogen from renewable resources, provide an alternative approach to synthesis of useful fuels and chemicals. People are increasingly interested in developing innovative carbon dioxide hydrogenation catalysts, and the pace of progress in this area is accelerating. Accordingly, this perspective presents current state of the art and outlook in synthesis of light olefins, dimethyl ether, liquid fuels, and alcohols through two leading hydrogenation mechanisms: methanol reaction and Fischer-Tropsch based carbon dioxide hydrogenation. The future research directions for developing new heterogeneous catalysts with transformational technologies, including 3D printing and artificial intelligence, are provided.

Controlled generation of acentric and homochiral coordination compounds from a versatile asymmetric ligand 4-(1H-1,2,4-triazol-3-yl)-4H-1,2,4-triazole.

Luminescent acentric and homochiral coordination compounds, which possess new topological networks, multiple helical structures and NLO properties, have been generated through the control of a versatile asymmetric ligand as well as inorganic anions, and this suggests a new protocol for preparing acentric and chiral materials.

Organically templated metal-organic framework with 2-fold interpenetrated {3(3).5(9).6(3)}-lcy net.

A new organic cation templated Zn(II) complex (Et3NH)[Zn4(ip)3(bta)3] (, ip = isophthalate, Hbta = benzotriazole) which consists of plate-like Zn4(bta)3 units bridged by ip ligands is reported; it is the first example of a 6-connected uninodal {3(3).5(9).6(3)}-lcy net which has never been observed previously in MOFs but has been theoretically anticipated.

Topology analysis and nonlinear-optical-active properties of luminescent metal-organic framework materials based on zinc/lead isophthalates.

Two 3D Zn(II) and Pb(II) isophthalates, [Zn(ip)]n (1) and [Pb4(mu4-O)(ip)3(H2O)]n (2) (H2ip = isophthalic acid), have been prepared under hydro(solvo)thermal conditions and characterized by single-crystal X-ray diffraction. The two complexes crystallize in different space groups (P4(3)2(1)2 for 1 and P2(1)/c for 2) and have different bridging modes of the ip ligand. The 3D framework of 1 is constructed by the interconnection of ZnO4 polyhedra via ip ligands, which represents a chiral net with PtS-type topology. In contrast, complex 2 is formed by the combination of Pb4O-cluster secondary building units and has a novel (3.4.5)(3(2).4(5).5(6).6(7).7(2)) topology, which is the first ever example of a (3,7)-connected net. Complex 1 displays a second harmonic generation efficiency of about 1.5 times that of KH2PO4. Optical properties and thermal stabilities of the two complexes have been studied. Additionally, the calculations of band structure and density of states of 1 have also been performed with the density functional theory method.

Transportation Spherical Watermarking.

During the past twenty years, there has been a great interest in the study of spread spectrum (SS) watermarking. However, it is still a challenging task to design a secure and robust SS watermarking method. In this paper, we first define a family of secure SS watermarking methods, named as spherical watermarking (SW). The watermarked correlation of SW is defined to be uniformly distributed on a spherical surface, and this makes SW be key-secure against the watermarked-only attack. Then, we propose an implementation of SW, called transportation SW (TSW), which is designed to decrease embedding distortion in a recursive manner using the transportation theory, meanwhile keeping the security of SW. Moreover, we present a theoretical analysis of the embedding distortion and robustness of the proposed method. Finally, extensive experiments are conducted on simulated signals and real images. The experimental results show that TSW is more robust than existing secure SS watermarking methods.

A Study on the Security Levels of Spread-Spectrum Embedding Schemes in the WOA Framework.

Security analysis is a very important issue for digital watermarking. Several years ago, according to Kerckhoffs' principle, the famous four security levels, namely insecurity, key security, subspace security, and stego-security, were defined for spread-spectrum (SS) embedding schemes in the framework of watermarked-only attack. However, up to now there has been little application of the definition of these security levels to the theoretical analysis of the security of SS embedding schemes, due to the difficulty of the theoretical analysis. In this paper, based on the security definition, we present a theoretical analysis to evaluate the security levels of five typical SS embedding schemes, which are the classical SS, the improved SS (ISS), the circular extension of ISS, the nonrobust and robust natural watermarking, respectively. The theoretical analysis of these typical SS schemes are successfully performed by taking advantage of the convolution of probability distributions to derive the probabilistic models of watermarked signals. Moreover, simulations are conducted to illustrate and validate our theoretical analysis. We believe that the theoretical and practical analysis presented in this paper can bridge the gap between the definition of the four security levels and its application to the theoretical analysis of SS embedding schemes.