Unveiling the Function of Oxygen Vacancy on Facet-Dependent CeO2 for the Catalytic Destruction of Monochloromethane: Guidance for Industrial Catalyst Design.

Secondary pollution remains a critical challenge for the catalytic destruction of chlorinated volatile organic compounds (CVOCs). By employing experimental studies and theoretical calculations, we provide valuable insights into the catalytic behaviors exhibited by ceria rods, cubes, and octahedra for monochloromethane (MCM) destruction, shedding light on the elementary reactions over facet-dependent CeO2. Our findings demonstrate that CeO2 nanorods with the (110) facet exhibit the best performance in MCM destruction, and the role of vacancies is mainly to form a longer distance (4.63 Å) of frustrated Lewis pairs (FLPs) compared to the stoichiometric surface, thereby enhancing the activation of MCM molecules. Subsequent molecular orbital analysis showed that the adsorption of MCM mainly transferred electrons from the 3σ and 4π* orbitals to the Ce 4f orbitals, and the activation was mainly caused by weakening of the 3σ bonding orbitals. Furthermore, isotopic experiments and theoretical calculations demonstrated that the hydrogen chloride generated is mainly derived from methyl in MCM rather than from water, and the primary function of water is to form excess saturated H on the surface, facilitating the desorption of generated hydrogen chloride.

Lean methane combustion over zeolite-supported Pd catalysts: Structure-performance relationship and deactivation mechanism.

Zeolites are a promising support for Pd catalysts in lean methane (CH4) combustion. Herein, three types of zeolites (H-MOR, H-ZSM-5 and H-Y) were selected to estimate their structural effects and deactivation mechanisms in CH4 combustion. We show that variations in zeolite structure and surface acidity led to distinct changes in Pd states. Pd/H-MOR with external high-dispersing Pd nanoparticles exhibited the best apparent activity, with activation energy (Ea) at 73 kJ/mol, while Pd/H-ZSM-5 displayed the highest turnover frequency (TOF) at 19.6 × 10-3 sec-1, presumably owing to its large particles with more step sites providing active sites in one particle for CH4 activation. Pd/H-Y with dispersed PdO within pore channels and/or Pd2+ ions on ion-exchange sites yielded the lowest apparent activity and TOF. Furthermore, Pd/H-MOR and Pd/H-ZSM-5 were both stable under a dry condition, but introducing 3 vol.% H2O caused the CH4 conversion rate on Pd/H-MOR drop from 100% to 63% and that on Pd/H-ZSM-5 decreased remarkably from 82% to 36%. The former was shown to originate from zeolite structural dealumination, and the latter principally owed to Pd aggregation and the loss of active PdO.

Asymmetric transmission for dual-circularly and linearly polarized waves based on a chiral metasurface.

We propose a chiral metasurface (CMS) that exhibits asymmetric transmission (AT) of double circularly and linearly polarized waves at the same frequency band. In order to realize the manipulation of electromagnetic (EM) waves in the whole space, the unit cell of CMS consists of three layers of dielectric substrate and four layers of metal patches. The Z-shaped chiral micro-structure and a grating-like micro-structure are proposed and designed to achieve AT. The simulated results show that the x-polarized wave that is incident along one direction can be transmitted into the right-hand circularly polarized (RHCP) wave and the left-hand circularly polarized (LHCP) wave that is incident along the opposite direction can be reflected as the LHCP wave in the frequency band of 4.69GHz-5.84 GHz. The maximum chirality response can be reflected by AT and circular dichroism (CD) and they can reach up to 0.38 and 0.75, respectively. In addition, we also produced the sample of CMS, and the experimental results are in good agreement with the simulated results.

Reconfigurable time-frequency division multiplexing metasurface: giving a helping hand to high signal-to-noise ratio and high data holographic imaging.

A holographic imaging system based on reconfigurable time-frequency division multiplexing metasurface (RTFDMM) has been designed, in an attempt to address the problems of insufficient flexibility, low signal-to-noise ratio (SNR), and low data of traditional metasurface imaging devices. The modified Gerchberg-Saxton (MGS) algorithm in the front end of this system has been proposed to calculate the phase distribution required by the diffraction metasurface at the back end. The 1-bit low loss reconfigurable metasurface has been desiged in X-band. To obtain the best imaging results, the appropriate ranges of imazging distance, pixel size and resolution ratio are given by adjusting the phase distribution of metasurface. Based on the MGS algorithm and the 1-bit metasurface, the high-quality imaging system has been successfully established through the time-frequency division multiplexing (TFDM) technology. The high SNR imaging can be generated with the expansion of the time domain, while the high data imaging can be yielded with the quantization of the frequency domain. The proof-of-concept has demonstrated that the high data, high SNR, and high flexibility of the RTFDMM are critical technologies for the advancement of detection imaging equipment. Therefore, there are great possibilities for RTFDMM holographic imaging system to be applied in the intelligent detection platform in the future.

Laminated mica nanosheets supported ionic liquid membrane for CO2 separation.

Mica has attracted great attention due to its excellent photoelectric property and it is mainly used in the optics and electronics area. High-quality mica nanosheets exfoliated from natural ground mica have been successfully achieved recently. It improves the application potential of mica as well as extending the application field to gas separation as a new two-dimensional (2D) material. Herein, we firstly constructed a mica membrane by regularly stacking mica nanosheets and then immobilized ionic liquid (IL) into its 2D channels to separate CO2 from H2, CH4 and N2. Gas diffusion is changed from Knudsen diffusion in the mica membrane to a solution-diffusion mechanism after inserting IL. The resultant membrane, the mica supported IL membrane (M-SILM), has about 80 GPU for CO2 permeance, and selectivity for CO2/H2, CO2/CH4 and CO2/N2 of 7.7, 28.6 and 87, respectively. It is the first time a mica nanosheet to construct a gas separation membrane has been used. As a cheap raw material with facile treating, mica shows promising potential for gas separation and competitiveness among 2D material supported IL membranes.

Asymmetric Construction of 3,3-Disubstituted Oxindoles Bearing Vicinal Quaternary-Tertiary Carbon Stereocenters Catalyzed by a Chiral-at-Rhodium Complex.

A highly diastereo- and enantioselective synthesis of 3,3-disubstituted oxindoles bearing vicinal quaternary-tertiary carbon centers is enabled by a chiral-at-rhodium Lewis acid catalyst starting from isatin N-protected ketimines and 2-acyl imidazoles. The excellent results with 93-99% yields, diastereoselectivities of 43:1 to >200:1, and high enantioselectivities of 98.4 to >99% confirm the potential of bis-cyclometalated rhodium catalysts for the development of effective asymmetric transformations.

Optical Anisotropy of Black Phosphorus in the Visible Regime.

The striking in-plane anisotropy remains one of the most intriguing properties for the newly rediscovered black phosphorus (BP) 2D crystals. However, because of its rather low-energy band gap, the optical anisotropy of few-layer BP has been primarily investigated in the near-infrared (NIR) regime. Moreover, the essential physics that determine the intrinsic anisotropic optical property of few-layer BP, which is of great importance for practical applications in optical and optoelectronic devices, are still in the fancy of theory. Herein, we report the direct observation of the optical anisotropy of few-layer BP in the visible regime simply by using polarized optical microscopy. On the basis of the Fresnel equation, the intrinsic anisotropic complex refractive indices (n-iκ) in the visible regime (480-650 nm) were experimentally obtained for the first time using the anisotropic optical contrast spectra. Our findings not only provide a convenient approach to measure the optical constants of 2D layered materials but also suggest a possibility to design novel BP-based photonic devices such as atom-thick light modulators, including linear polarizer, phase plate, and optical compensator in a broad spectral range extending to the visible window.

Birefringence-Directed Raman Selection Rules in 2D Black Phosphorus Crystals.

The incident and scattered light engaged in the Raman scattering process of low symmetry crystals always suffer from the birefringence-induced depolarization. Therefore, for anisotropic crystals, the classical Raman selection rules should be corrected by taking the birefringence effect into consideration. The appearance of the 2D anisotropic materials provides an excellent platform to explore the birefringence-directed Raman selection rules, due to its controllable thickness at the nanoscale that greatly simplifies the situation comparing with bulk materials. Herein, a theoretical and experimental investigation on the birefringence-directed Raman selection rules in the anisotropic black phosphorus (BP) crystals is presented. The abnormal angle-dependent polarized Raman scattering of the Ag modes in thin BP crystal, which deviates from the normal Raman selection rules, is successfully interpreted by the theoretical model based on birefringence. It is further confirmed by the examination of different Raman modes using different laser lines and BP samples of different thicknesses.

Polyphyllin I Mitigated IL-1ß-Induced Chondrocytes Damage through Downregulating TWIST1 Expression.

BACKGROUND: Osteoarthritis (OA) is a chronic joint disease characterized by the degradation of articular cartilage. Polyphyllin I (PPI) has anti-inflammatory effects in many diseases. However, the mechanism of PPI in OA remains unclear.

Deep Location Soft-Embedding-Based Network with Regional Scoring for Mammogram Classification.

Early detection and treatment of breast cancer can significantly reduce patient mortality, and mammogram is an effective method for early screening. Computer-aided diagnosis (CAD) of mammography based on deep learning can assist radiologists in making more objective and accurate judgments. However, existing methods often depend on datasets with manual segmentation annotations. In addition, due to the large image sizes and small lesion proportions, many methods that do not use region of interest (ROI) mostly rely on multi-scale and multi-feature fusion models. These shortcomings increase the labor, money, and computational overhead of applying the model. Therefore, a deep location soft-embedding-based network with regional scoring (DLSEN-RS) is proposed. DLSEN-RS is an end-to-end mammography image classification method containing only one feature extractor and relies on positional embedding (PE) and aggregation pooling (AP) modules to locate lesion areas without bounding boxes, transfer learning, or multi-stage training. In particular, the introduced PE and AP modules exhibit versatility across various CNN models and improve the model's tumor localization and diagnostic accuracy for mammography images. Experiments are conducted on published INbreast and CBIS-DDSM datasets, and compared to previous state-of-the-art mammographic image classification methods, DLSEN-RS performed satisfactorily.

Rational molecular design converting fascaplysin derivatives to potent broad-spectrum inhibitors against bacterial pathogens via targeting FtsZ.

The filamentous temperature-sensitive mutant Z protein (FtsZ), a key player in bacterial cell division machinery, emerges as an attractive target to tackle the plight posed by the ever growing antibiotic resistance over the world. Therefore in this regard, agents with scaffold diversities and broad-spectrum antibacterial activity against Gram-positive and Gram-negative pathogens are highly needed. In this study, a new class of marine-derived fascaplysin derivatives has been designed and synthesized by Suzuki-Miyaura cross-coupling. Some compounds exhibited potent bactericidal activities against a panel of Gram-positive (MIC = 0.024-6.25 µg/mL) and Gram-negative (MIC = 1.56-12.5 µg/mL) bacteria including methicillin-resistant S. aureus (MRSA). They exerted their effects by dual action mechanism via disrupting the integrity of the bacterial cell membrane and targeting FtsZ protein. These compounds stimulated polymerization of FtsZ monomers and bundling of the polymers, and stabilized the resulting polymer network, thus leading to the dysfunction of FtsZ in cell division. In addition, these agents showed negligible hemolytic activity and low cytotoxicity to mammalian cells. The studies on docking and molecular dynamics simulations suggest that these inhibitors bind to the hydrophilic inter-domain cleft of FtsZ protein and the insights obtained in this study would facilitate the development of potential drugs with broad-spectrum bioactivities.

Incorporating Polarization and Charge Transfer into a Point-Charge Model for Water Using Machine Learning.

Rigid nonpolarizable water models with fixed point charges have been widely employed in molecular dynamics simulations due to their efficiency and reasonable accuracy for the potential energy surface. However, the dipole moment surface of water is not necessarily well-described by the same fixed charges, leading to failure in reproducing dipole-related properties. Here, we developed a machine-learning model trained against electronic structure data to assign point charges for water, and the resulting dipole moment surface significantly improved the predictions of the dielectric constant and the low-frequency IR spectrum of liquid water. Our analysis reveals that within our atom-centered point-charge description of the dipole moment surface, the intermolecular charge transfer is the major source of the peak intensity at 200 cm-1, whereas the intramolecular polarization controls the enhancement of the dielectric constant. The effects of exact Hartree-Fock exchange in the hybrid density functional on these properties are also discussed.

Occurrence rates and risk factors of in-hospital venous thromboembolism, major bleeding, and death in patients receiving fondaparinux after orthopedic surgery or trauma surgery.

AIM: Fondaparinux is a synthetic anticoagulant that inhibits thrombosis by suppressing factor Xa. The efficacy of fondaparinux for orthopedic surgeries has been revealed by several foreign studies; however, relevant evidence in Chinese patients is lacking. This study intended to investigate the occurrence rate and risk factors of in-hospital venous thromboembolism (VTE), major bleeding, and death in patients receiving fondaparinux after orthopedic surgery or trauma surgery. METHODS: Totally, 1258 patients who received fondaparinux after orthopedic surgery or trauma surgery were retrospectively enrolled. Meanwhile, in-hospital VTE, major bleeding, and death were obtained for assessment. Besides, adverse events were recorded. RESULTS: The occurrence rates of in-hospital VTE, major bleeding, and death were 2.5%, 21.8%, and 0.0%, respectively. The multivariate logistic regression analysis revealed that only age (> 60 years vs. ≤ 60 years) (odd ratios (OR) = 3.380, P = 0.013) was independently correlated with increased risk of in-hospital VTE. Additionally, osteoarthritis diagnosis (OR = 3.826, P < 0.001), femoral head necrosis diagnosis (OR = 1.809, P = 0.034), hip replacement (vs. internal fracture fixation) (OR = 2.199, P = 0.007), knee replacement (vs. internal fracture fixation) (OR = 2.781, P = 0.002), and serum creatinine (abnormal vs. normal) (OR = 1.677, P = 0.012) were independently linked to a higher risk of in-hospital major bleeding. Moreover, the common adverse events included pain (56.6%), wound bleeding (23.0%), increased drainage (5.2%), etc. CONCLUSION: Fondaparinux realizes low occurrence rates of in-hospital VTE and major bleeding with tolerable adverse events in patients receiving orthopedic surgery or trauma surgery.

Raman Characterization of the In-Plane Stress Tensor of Gallium Nitride.

Experimental characterization of the in-plane stress tensor is a basic requirement for the development of GaN strain engineering. In this work, a theoretical model of stress characterization for GaN using polarized micro-Raman spectroscopy was developed based on elasticity theory and lattice dynamics. Compared with other works, the presented model can give the quantitative relationship between all components of the in-plane stress tensor and the measured Raman shift. The model was verified by a calibration experiment under step-by-step uniaxial compression. By combining the stress characterization model with the expanding cavity model, the in-plane residual stress component field around Berkovich indentation on the (0001) plane GaN was achieved. The experimental results show that the distributions of the stress components, which significantly differed from the distribution of the Raman shift, were closely related to the GaN crystal structure and exhibited a gradient along each crystal direction.

Cyclodextrin-dendrimers nanocomposites functionalized high performance liquid chromatography stationary phase for efficient separation of aromatic compounds.

In this work, novel cyclodextrin-dendrimers nanocomposites functionalized high performance liquid chromatography stationary phases were developed for efficient separation of aromatic compounds. ß-cyclodextrin was grafted onto the surface of silica gel matrix with poly (amidoamine) dendrimers as spacers. Scanning electron microscope, fourier transform infrared spectroscopy, element analysis and Brunner-Emmet-Teller measurement proved the successful grafting of cyclodextrin-dendrimers nanocomposites. The obtained stationary phases showed satisfactory separation effects for alkylbenzenes and benzenesulfonic acid substituents in reverse phase liquid chromatography mode. Weak hydrophilic and ion exchange interactions were also confirmed at the same time. Meanwhile, the effects of dendrimers and cyclodextrin on the chromatography performance were discussed. Separation mechanism of the stationary phases were verified by two-dimensional nuclear magnetic resonance technology, and the result implied that the proposed cyclodextrin-dendrimers nanocomposites functionalized stationary phases have significant prospects for separation and determination of more aromatic compounds in future.

Cytological and physiological tolerance of transgenic tobacco to Cd stress is enhanced by the ectopic expression of SmZIP8.

Zrt and Irt-like proteins (ZIPs) are responsible for transporting various divalent metal cations. However, information about the characteristics of the cellular and physiological tolerance of plant ZIPs to Cd stress is still limited. The expression levels of SmZIP8 in Salix matsudana Koidz were upregulated by Cd stress. The complete length of SmZIP8 from S. matsudana was cloned, and transgenic tobacco was obtained by Agrobacterium-mediated transformation. Then, the tolerance to Cd stress of wild-type (WT) and transgenic tobacco seedlings was analyzed and compared by studying the cytotoxicity of the root tip cells, photosynthetic parameters, histochemical staining of O2- and H2O2, the activities of antioxidant enzymes, and malondialdehyde content under Cd stress. In comparison with WT tobacco, the ectopic expression of SmZIP8 in tobacco promoted the cytological tolerance of the transgenic tobacco to Cd stress by reducing cell damage, raising the mitotic indexes, and reducing the rate of chromosome aberration of the root cells. Meanwhile, the results of increased photosynthetic capacity, decreased oxidative damage, and activated antioxidant enzymes showed that the physiological tolerance of transgenic tobacco to Cd was enhanced. The principal component analysis for the above physiological parameters explained 96.08% of the total variance (PC1, 77.77%; PC2, 18.31%), indicating a significant difference in Cd tolerance abilities between the tobacco expressing SmZIP8 and WT tobacco. Therefore, SmZIP8 may be considered as an important genetic resource for the phytoremediation of Cd or other heavy metal pollution via the use of transgenic plants obtained through genetic transformation.

Determining Partial Atomic Charges for Liquid Water: Assessing Electronic Structure and Charge Models.

Partial atomic charges provide an intuitive and efficient way to describe the charge distribution and the resulting intermolecular electrostatic interactions in liquid water. Many charge models exist and it is unclear which model provides the best assignment of partial atomic charges in response to the local molecular environment. In this work, we systematically scrutinize various electronic structure methods and charge models (Mulliken, natural population analysis, CHelpG, RESP, Hirshfeld, Iterative Hirshfeld, and Bader) by evaluating their performance in predicting the dipole moments of isolated water, water clusters, and liquid water as well as charge transfer in the water dimer and liquid water. Although none of the seven charge models is capable of fully capturing the dipole moment increase from isolated water (1.85 D) to liquid water (about 2.9 D), the Iterative Hirshfeld method performs best for liquid water, reproducing its experimental average molecular dipole moment, yielding a reasonable amount of intermolecular charge transfer, and showing modest sensitivity to the local water environment. The performance of the charge model is dependent on the choice of the density functional and the quantum treatment of the environment. The computed molecular dipole moment of water generally increases with the percentage of the exact Hartree-Fock exchange in the functional, whereas the amount of charge transfer between molecules decreases. For liquid water, including two full solvation shells of surrounding water molecules (within about 5.5 Å of the central water) in the quantum chemical calculation converges the charges of the central water molecule. Our final pragmatic quantum chemical charge-assigning protocol for liquid water is the Iterative Hirshfeld method with M06-HF/aug-cc-pVDZ and a quantum region cutoff radius of 5.5 Å.

Photocatalytic enantioselective α-aminoalkylation of acyclic imine derivatives by a chiral copper catalyst.

Copper-based asymmetric photocatalysis has great potential in the development of green synthetic approaches to chiral molecules. However, there are several formidable challenges associated with such a conception. These include the relatively weak visible light absorption, short excited-state lifetimes, incompatibility of different catalytic cycles, and the difficulty of the stereocontrol. We report here an effective strategy by means of single-electron-transfer (SET) initiated formation of radicals and photoactive intermediates to address the long-standing problems. Through elaborate selection of well-matched reaction partners, the chiral bisoxazoline copper catalyst is engaged in the SET process, photoredox catalysis, Lewis acid activation and asymmetric induction. Accordingly, a highly enantioselective photocatalytic α-aminoalkylation of acyclic imine derivatives has been accessed. This strategy sheds light on how to make use of diverse functions of a single transition metal catalyst in one reaction, and offers an economic and simplified approach to construction of highly valuable chiral vicinal diamines.

Acetaminophen aggravates fat accumulation in NAFLD by inhibiting autophagy via the AMPK/mTOR pathway.

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease which affects millions of people worldwide. Acetaminophen (APAP) overdose is the leading cause of acute liver failure. In this study, APAP (50, 100, 200 mg/kg) were employed on mice fed with a high-fat diet, and APAP (2, 4, 8 mM) were cultured with L02 cells in the presence of alcohol and oleic acid. APAP treatment significantly aggravated hepatic lipid accumulation, increased the serum levels of triglyceride (TG), alanine aminotransferase (ALT) and aspartate aminotransferase (AST), and increased hepatic lipid accumulation in H&E and Oil red O staining results. Transmission electron microscopy (TEM) found fewer number of autophagosomes in APAP (100 mg/kg) treated group. Immunohistochemistry analysis showed the intensity of hepatic mTOR was increased and AMPK was decreased in 200 mg/kg APAP treated group. Western blot analysis showed APAP treatment decreased the levels of LC3-Ⅱ, Beclin1 and AMPK, while increased the levels of mTOR and SREBP-1c, respectively. In vitro study showed APAP treatment obviously increased TG activities in cell supernatant, and Oil red O staining had the same results. Western blot analysis demonstrated APAP treatment decreased the levels of LC3-Ⅱ, Beclin1 and AMPK, increased the levels of mTOR and SREBP-1c, but rapamycin treatment significantly reversed these effects of APAP. In conclusion, therapeutic dosages of APAP aggravates fat accumulation in NAFLD, the potential mechanism might be involved in inhibiting autophagy associated with the AMPK/mTOR pathway, and patients with NAFLD should use a lower dose of APAP.

Diagnostic and prognostic value of WNT family gene expression in hepatitis B virus­related hepatocellular carcinoma.

The aim of the present study was to investigate the diagnostic and prognostic value of Wingless­type MMTV integration site (WNT) gene family expression in patients with hepatitis B virus (HBV)­related hepatocellular carcinoma (HCC). The clinical data of the patients and gene expression levels were downloaded from Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA) databases. Receiver operating characteristic curve analysis was used to investigate the diagnostic value of WNT genes. Cox proportional hazard regression analysis and Kaplan­Meier survival analysis were performed to evaluate the association of WNT gene expression level with overall survival (OS) and recurrence­free survival (RFS). A nomogram was constructed for the prediction of prognosis. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated. Diagnostic receiver operating characteristic curve analysis suggested that WNT2 had a high diagnostic value, with an area under the curve (AUC) of >0.800 (P<0.0001, AUC=0.810, 95% CI: 0.767­0.852). Survival analysis indicated that the expression level of WNT1 was significantly associated with OS and RFS (adjusted P=0.033, adjusted HR=0.607, 95% CI: 0.384­0.960; and adjusted P=0.007, adjusted HR=0.592, 95% CI: 0.404­0.868, respectively). In the TCGA validation cohort, we also observed that WNT2 was significantly differentially expressed between HCC tissues and adjacent non­tumor tissues, and WNT1 was associated with both the OS and RFS of HCC. Therefore, through the GSE14520 HBV­related HCC cohort we concluded that WNT2 may serve as a diagnostic biomarker and WNT1 may serve as a prognostic biomarker. These results may also be extended to TCGA HCC verification cohort.