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Photo‐thermochemical cycle (PTC) is a promising method to converting CO2 to solar fuels. To study the mechanism of CO2 reduction based on PTC, sol‐gel synthesized titanium dioxide (ST) and Mn‐doped TiO2 (MT) films were produced and applied to the PTC under simulated solar light irradiation. Commercial P25 (PT) was used as a reference. Experiments show that Mn‐doped TiO2 produced more CO than undoped TiO2 and P25. The average CO production of 1.0 wt% MT by the PTC was 32.19 μmol⋅m−2⋅h−1), 4.36 times than that of ST and 3.63 times that of PT. Various characterization methods were conducted to investigated the effect of Mn ions doping on the photoresponse and charge transfer of samples. Density functional theory (DFT) calculations were also performed to verify the analysis and enhance the PTC mechanism. In conclusion, several key factors that Mn ions promote CO2 conversion have been clarified. Combine solar heat and light! To reduce CO2, photo‐thermochemical (PTC) cycle involves both solar light and thermal energy. Photo‐induced oxygen vacancy (VO) is the key to reduce CO2 in thermal step. Introducing Mn to TiO2 significantly broadens its visible light response and decreases the VO formation energy by DFT calculations. Experimental results show that doping TiO2 with Mn significantly enhances CO2 reduction by PTC under simulated solar light irradiation. [ABSTRACT FROM AUTHOR]

The combined finite-discrete element method (FDEM) is an advanced finite and discrete element coupling method, which can commendably simulate the large deformation and fracture process of materials. The explicit solution method in FDEM is naturally suitable for solving dynamic problems, and the key to dynamic analysis is to establish artificial boundary conditions that can be prepared to simulate infinite domain motion. At present, there is only the viscous boundary condition in the original FDEM, but this is only applicable for solving the internal source wave problems (e.g., blasting, mechanical vibration), and there are no artificial boundary conditions for solving the external source wave problems (e.g., earthquake). Therefore, three artificial boundary conditions have been developed in the present study to enhance the ability of FDEM to conduct dynamic response analysis. Firstly, the basic principle of FDEM and the existing viscous boundary condition are briefly introduced. Then, three newly added boundary conditions are introduced in sequence: (1) viscous-spring boundary condition, which can absorb stress wave energy at the boundary and restore the residual displacement to meet the actual engineering; (2) free-field boundary condition, which is coupled with free-field motion to absorb scattered waves at the lateral boundaries of the model, and the algorithms of mesh matching retrieval and coupling calculation are also introduced; (3) static-dynamic unified boundary condition, which can accurately transform the fixed boundary under the quasi-static analysis into the non-reflective boundary condition under the dynamic analysis. Finally, several classic models are built to verify the feasibility of the newly added boundary conditions. The comparison with the shaking table test also shows that the improved FDEM can be used for seismic response analysis under actual earthquakes. [ABSTRACT FROM AUTHOR]

To dissociate carbon dioxide (CO 2 ) using solar energy, a novel photo-thermochemical cycle combining photochemistry with thermochemistry is proposed in this paper. After illuminating titanium dioxide (TiO 2 ) in a helium (He) atmosphere by ultraviolet (UV) irradiation, CO 2 was input and converted to carbon monoxide (CO) under heating in an enclosed cavity. To determine the optimal heating temperature, sets of four consecutive cycles were performed at temperatures from 573 K to 873 K. The preferred temperature was found to be 773 K. CO was stably produced in five successive cycles at 773 K, demonstrating the method’s possibility. Scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD) were employed to assess the crystal structure and morphology. X-ray photoelectron spectroscopy (XPS) and photoluminescence (PL) analyses were also conducted to investigate the charge transfer and reaction mechanisms on the TiO 2 surface. Finally, a charge transfer mechanism is tentatively proposed. [ABSTRACT FROM AUTHOR]

Surface re-construction was a common phenomenon for non-oxide compound electrocatalysts in anodic oxidation reaction in alkaline electrolyte but surface deactivation arising from excessive oxidation/hydroxylation was critical hindrance to the long-term stability. Herein, a unique anode-cathode interchangeable electrocatalysis strategy is proposed for methanol upgrading reaction (MUR) and hydrogen co-generation in membrane-free electrolyzer. A periodical electrolysis is taken place for the Ni 3 S 2 /CNTs electrode at positive/negative currents over time. Compared with the traditional chronopotentiometry mode, the MUR-HER coupled reactions by periodically switching anode/cathode per hour present an excellent long-term stability at high current densities of ± 100 mA cm−2, in which the Faradaic efficiencies for both H 2 and value-added formate are greater than 95%. Substantial experimental results and deep theoretical DFT studies signify that the successful application of this strategy is mainly due to the reversible modulation of oxidation/hydroxylation status on Ni 3 S 2 surface, which effectively prevent the surface active structures of electrocatalysts from over-oxidation. [Display omitted] • A periodical electrolysis is taken place with Ni 3 S 2 /CNTs electrode at positive or negative current over time. • Long-term stable methanol upgrading and hydrogen co-generation are achieved in a membrane-free electrolyzer. • Substantial XPS, XAFS and DFT studies indicate that the surface critical active sites can be in situ revived. • Such unique anode-cathode interchangeable strategy effectively prevents catalyst surface from over-oxidation. • It successfully brings about the reversible modulation of oxidation/hydroxylation status on Ni 3 S 2 surface. [ABSTRACT FROM AUTHOR]

The combined finite-discrete element method (FDEM) is an advanced finite and discrete element coupling method. This study further applies it to the problem of stress wave propagation in the jointed rock mass. Firstly, the fundamental theory of FDEM is briefly described and the methods commonly used in FDEM to characterize structural planes are comprehensively analyzed. Then, based on the viscous boundary condition (VBC), the viscous-spring boundary condition (VSBC) is added to absorb the reflected wave at the artificial boundary and restore the residual displacement to meet the actual engineering. In addition, the application range of the VBC and VSBC is verified, which indicates that the VBC and VSBC in the improved FDEM can be well applied not only to the continuum range but also to the case of the new fracture formed. Finally, several classic models are solved to verify the stress wave propagation across different types of joints by FDEM. The results reveal that results from FDEM agree well with analytical solutions based on the displacement discontinuity model and numerical solutions from universal distinct element code (UDEC), which means that the improved FDEM can capably and accurately simulate wave propagation in the jointed rock mass. [ABSTRACT FROM AUTHOR]

[Display omitted] • A wavelength-dependent local field was constructed to greatly enhance CO 2 adsorption and key intermediates formation. • The CO/H 2 ratio could be adjusted from 0.65 to 1.84 by adjusting LSPR intensities of samples. • An unbiased solar-to-gaseous-carbon-fuel (SGCF) efficiency of 0.51 % could be achieved. • CO, CH 4 and formate can be stably produced with using a neutral solution based on low-cost metal oxides. • Both internal and interfacial charge carrier transfer can be enhanced to avoid energy loss of recombination. The fabrication of an efficient and low-cost photocathode still remains a big challenge. We herein report a Ag/Cu x O@rGO/Mo photocathode for CO 2 conversion. A unique wavelength-dependent performance is found to enhance the formation of the key intermediate groups by exciting photothermal local surface plasmonic resonance (LSPR) using the lights with wavelengths ranging from 550 to 600 nm. CO, H 2 and CH 4 can be stably produced with dual photoelectrodes using a neutral solution. An unbiased solar-to-gaseous-carbon-fuel efficiency (SGCF) of 0.51 % has been achieved, which sets a record for carbon gas fuel production with binary photoelectrodes. In addition, the CO/H 2 ratio could be tuned in the range from 0.65 to 1.84, which makes it possible to fine tune the syngas production. The excellent PEC CO 2 reduction capability achieved by the new wavelength-dependent catalytic route may shine some lights for the future design and development of the next-generation PEC materials and devices. [ABSTRACT FROM AUTHOR]

Electro-oxidative organic upgrading is recently considered as a promising strategy for energy saved H 2 co-generation but still challenging for high productivity of value-added chemicals at large current density. Herein, the synthesized defects-rich Ni 3 S 2 -CNFs nanoheterostructures exhibit robust electrocatalytic performance for selectively catalyzing methanol to value-added formate with high productivity and without CO 2 emission, in which the large current density (> 700 mA cm−2) is achieved with high faradaic efficiency (> 90%). By replacing the sluggish OER, the methanol upgrading reaction can greatly boost H 2 co-generation from water with reduced energy consumption. DFT calculations indicate the in situ formed Ni–OOH and SO x species with synergistic effect can effectively modulate the d band center of Ni 3 S 2 in Ni 3 S 2 -CNFs nanoheterostructures, acting as unique collaborative active sites for the thermodynamically favorable conversion from methanol to formate and suppressing the further oxidation to CO 2 , resulting in the high activity and selectivity of CO 2 -emission-free methanol upgrading reaction. The novel defects-rich Ni 3 S 2 -CNFs nanoheterostructures achieve the electrocatalytic CH 3 OH selective upgrading at large current densities (> 700 mA cm−2) without CO 2 emission, producing value-added chemical (formate) with high productivity and simultaneously boosting the cathodic H 2 generation with reduced energy consumption. ga1 • Novel defects-rich Ni 3 S 2 -CNFs nanoheterostructures are synthesized as highly active and selective electrocatalysts. • The electro-oxidative methanol selective upgrading is achieved at large current density (> 700 mA cm−2) without CO 2 emission. • The co-generation of value-added chemical and H 2 is achieved with high productivity and less energy consumption. • Ni–OOH and SO x species with synergistic effect act as novel collaborative active sites for methanol selective upgrading. [ABSTRACT FROM AUTHOR]

A convenient interfacial engineering strategy is developed to the construction of worm-shaped palladium nanocrystals strongly coupled with polyelectrolyte-modified Ti 3 C 2 T x MXene via direct electrostatic attraction, which express exceptional electrocatalytic ability toward methanol oxidation. [Display omitted] • An interfacial engineering strategy is developed to construct Pd nanoworm/MXene catalyst. • The incorporation of PDDA ensures strong electrostatic attraction between Pd and MXene. • The resultant catalyst expresses superior catalytic performance for methanol oxidation. • DFT calculation discloses the enhanced antitoxic ability of Pd nanoworm/MXene toward CO. The development of high-efficiency methanol oxidation electrocatalysts with acceptable costs is central to the practical use of direct methanol fuel cell. In this work, a convenient interfacial engineering strategy is developed to the design and construction of quasi-one-dimensional worm-shaped palladium nanocrystals strongly coupled with positively-charged polyelectrolyte-modified Ti 3 C 2 T x MXene (Pd NWs/PDDA-MX) via the direct electrostatic attractions. Because of the intriguing structural features including ultrathin-sheet nature, homogeneous Pd dispersion, numerous grain boundaries, strong electronic interaction, and high metallic conductivity, the as-fabricated Pd NWs/PDDA-MX hybrid shows superior electrocatalytic performance with a large electrochemically active surface area of 105.3 m2 g−1, a high mass activity of 1526.5 mA mg−1, and reliable long-term durability towards alkaline methanol oxidation reaction, far outperforming the commercial Pd nanoparticle/carbon catalysts. Density functional theory calculation further demonstrate that there are strong electronic interactions in the Pd nanoworm/Ti 3 C 2 T x model with a depressed CO adsorption energy, thereby guaranteeing a stable interfacial contact as well as strong antitoxic ability. [ABSTRACT FROM AUTHOR]

Background: Studies have highlighted a possible crosstalk between the pathogeneses of COVID-19 and systemic lupus erythematosus (SLE); however, the interactive mechanisms remain unclear. We aimed to elucidate the impact of COVID-19 on SLE using clinical information and the underlying mechanisms of both diseases. Methods: RNA-seq datasets were used to identify shared hub gene signatures between COVID-19 and SLE, while genome-wide association study datasets were used to delineate the interaction mechanisms of the key signaling pathways. Finally, single-cell RNA-seq datasets were used to determine the primary target cells expressing the shared hub genes and key signaling pathways. Results: COVID-19 may affect patients with SLE through hematologic involvement and exacerbated inflammatory responses. We identified 14 shared hub genes between COVID-19 and SLE that were significantly associated with interferon (IFN)-I/II. We also screened and obtained four core transcription factors related to these hub genes, confirming the regulatory role of the IFN-I/II-mediated Janus kinase/signal transducers and activators of transcription (JAK-STAT) signaling pathway on these hub genes. Further, SLE and COVID-19 can interact via IFN-I/II and IFN-I/II receptors, promoting the levels of monokines, including interleukin (IL)-6/10, tumor necrosis factor-α, and IFN-γ, and elevating the incidence rate and risk of cytokine release syndrome. Therefore, in SLE and COVID-19, both hub genes and core TFs are enriched within monocytes/macrophages. Conclusions: The interaction between SLE and COVID-19 promotes the activation of the IFN-I/II-triggered JAK-STAT signaling pathway in monocytes/macrophages. These findings provide a new direction and rationale for diagnosing and treating patients with SLE–COVID-19 comorbidity. [ABSTRACT FROM AUTHOR]

Heat induced by solar irradiation can alter crystal structures and interfacial barriers, which may subsequently impact the generation, transport and recombination of photoinduced carriers during the radiative conversion of semiconductors. However, this factor is often ignored in photoreactions. Thus, this study investigates the influence and mechanism of the thermal effect on radiative conversion in photoreactions. We find that when the temperature increases, 1) the radiative absorbance is broadened, 2) the ability of photoinduced electrons to drive reactions is enhanced, and 3) better mobility of photoinduced carriers is achieved. Interestingly, the radiative recombination of ZnO and In 2 O 3 decreased and increased, respectively during heating, which resulted in increasing and decreasing photocurrents in the corresponding sample. Furthermore, after co-doping In 2 O 3 with Cu and Fe, we reversed the trend of radiative recombination from increasing to decreasing with increasing temperature. Thus, the H 2 production increased by 2.53 times at 250 °C relative to that at 150 °C during the photothermal reaction using Cu3/Fe1–In 2 O 3. Finally, we successfully proved that the thermal effect could be converted from a harmful factor into a beneficial role during radiative conversion. This work may inspire more innovative ideas related to the mechanism and utilization of the thermal effect in solar conversion. [Display omitted] • The mechanism of temperature effects on photoreaction is elucidated. • Unique material design reverses temperature effect on radiative recombination. • Cu/Fe doping enables an extended light response range and longer carrier lifetime. • This work provides an innovative path for improving photothermal catalysis. [ABSTRACT FROM AUTHOR]

The (1-x)CaZrO 3 -xSrTiO 3 solid-solution thin films were prepared with different compositions from x = 0.05 to x = 0.45. The as-prepared thin films experienced such a crystal structure transition process from orthorhombic to pseudo cubic and then to cubic as the x increases. Among the as-prepared films, the smallest expansion ratio of lattice volume with temperatures, and the highest temperature stability of dielectric response and leakage current density at high voltage were found in the x = 0.3 thin films. The relationship between the tolerance factor and the temperature stability was analyzed from the crystal structure dependence of the absorbed thermal energy distribution. Finally, the x = 0.3 thin films were developed into thin-film capacitors, which showed high DC resistance and uniform capacitance properties. The result also shows that high temperature stability of the perovskite-type paraelectric thin films could be realized through the phase boundary design, and further improved by optimizing the temperature stability of the lattice structure. [ABSTRACT FROM AUTHOR]

Background: Pregnancy is a unique physiological condition with the cellular immune functions compromised at some extents to allow the mature of growing fetus. Whether pregnancy may influence the replication of hepatitis B virus (HBV) is less studied. The present study aimed to investigate the influence of pregnancy on the replication of HBV and expression of viral antigens by comparing the levels of HBV DNA and viral antigens in pregnant and non-pregnant women.Methods: A total of 727 HBsAg-positive serum samples, collected from 214 pregnant women and 513 non-pregnant women of childbearing age, were included. Based on the pregnancy status, subjects were divided into four groups: nulliparous (n = 158), pregnant (n = 214), 7-12 months postpartum (n = 170), and 2-5 years postpartum (n = 185). The levels of hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg) were quantitatively measured with microparticle enzyme immunoassay. HBV DNA levels were detected by fluorescent real-time PCR.Results: The median ages of four groups were 25.0, 25.3, 26.2 and 29.3 years, respectively (p < 0.01). HBeAg-positive proportions were 34.2, 33.6, 35.3 and 29.2%, respectively (p = 0.624). HBV DNA levels in HBeAg-positive women were higher than those in HBeAg-negative women (7.88 vs 2.62 log IU/ml, p < 0.001). HBV DNA levels in the four groups with positive HBeAg were 7.8, 7.7, 8.0 and 8.0 log IU/ml, respectively (p = 0.057), while HBsAg titers were 4.4, 4.5, 4.6 and 4.8 log IU/ml (p = 0.086) and HBeAg titers were 3.1, 3.0, 3.1 and 3.0 log S/CO (p = 0.198). In the four groups with negative HBeAg, HBV DNA levels were 2.3, 2.6, 2.5 and 2.8 log IU/ml, respectively (p = 0.085), while HBsAg titers were 3.1, 3.3, 3.3 and 3.0 log IU/ml (p = 0.06).Conclusions: Serum levels of HBV DNA and viral antigens showed no significant changes in nulliparous, pregnant, and postpartum women, regardless of the HBeAg status. The results indicate that pregnancy has little influence on the replication of HBV and the expression of viral antigens. [ABSTRACT FROM AUTHOR]

The components and pore structure of shale are complex due to the heterogeneous distribution of organic matter and the complex distributions of the minerals. The digital core, possessing the advantages of being economical and reusable, can be widely used to directly characterize the three dimensional (3D) micro-pore structure and to numerically simulate its physical properties. During construction of a digital shale core, it is a challenge to solve the multicomponent segmentation for the digital shale core, the contradiction between the sample size and image resolution, and the identification of the pore types in the 3D pore space. Therefore, an automatic workflow based on the gray gradient-maximum entropy-3D morphology was developed. The gray gradient-maximum entropy algorithm was used to segment each sub-image of focused ion beam scanning electron microscope images to generate segmented images. On this basis, the pore size distribution was optimized via 3D morphological erosion. Based on the concept of pore clusters, the organic and inorganic pores were identified using the 3D morphological method for the first time. The construction of a multicomponent digital shale core was realized. The 3D micro-pore structure of the organic and inorganic pores was characterized by pore connectivity, heterogeneity, and pore size distribution. The accuracy of the proposed method was verified using low-temperature N2 adsorption experiment data. The results of this study provide new insight into the multicomponent digital shale core construction and lay the foundation for the characterization of the petrophysical properties and micro-/nano-scale fluid flow simulations of shale. [ABSTRACT FROM AUTHOR]

Phenotypic transformation of macrophages plays important immune response roles in the occurrence, development and regression of periodontitis. Under inflammation or other environmental stimulation, mesenchymal stem cells (MSCs) exert immunomodulatory effects through their secretome. It has been found that secretome derived from lipopolysaccharide (LPS)-pretreated or three-dimensional (3D)-cultured MSCs significantly reduced inflammatory responses in inflammatory diseases, including periodontitis, by inducing M2 macrophage polarization. In this study, periodontal ligament stem cells (PDLSCs) pretreated with LPS were 3D cultured in hydrogel (termed SupraGel) for a certain period of time and the secretome was collected to explore its regulatory effects on macrophages. Expression changes of immune cytokines in the secretome were also examined to speculate on the regulatory mechanisms in macrophages. The results indicated that PDLSCs showed good viability in SupraGel and could be separated from the gel by adding PBS and centrifuging. The secretome derived from LPS-pretreated and/or 3D-cultured PDLSCs all inhibited the polarization of M1 macrophages, while the secretome derived from LPS-pretreated PDLSCs (regardless of 3D culture) had the ability to promote the polarization of M1 to M2 macrophages and the migration of macrophages. Cytokines involved in the production, migration and polarization of macrophages, as well as multiple growth factors, increased in the PDLSC-derived secretome after LPS pretreatment and/or 3D culture, which suggested that the secretome had the potential to regulate macrophages and promote tissue regeneration, and that it could be used in the treatment of inflammation-related diseases such as periodontitis in the future. [ABSTRACT FROM AUTHOR]

The traditional two-step thermochemical cycle of water-splitting that is based on metal-oxide redox pairs requires a high reaction temperature. In this study, we introduced a photochemical reaction into this thermochemical cycle and established a novel photo-thermochemical cycle. In this new cycle, the process by which metal oxides are reduced through concentrated solar energy is replaced with a photochemical reaction while water is still dissociated via a thermochemical reaction. Thus, photo-thermochemical cycles that combine these two reactions can be initiated at relatively low temperatures, unlike thermochemical cycles operated at extremely high temperatures. In this research, TiO 2 was used as the catalyst, experiments were conducted to evaluate the feasibility of the proposed cycle, and a preliminary mechanism was developed for this cycle. [ABSTRACT FROM AUTHOR]

• Developed a multiphysics field model based on finite volume. • Predicts the thermal behavior and the defect generation in the molten pool.. • Detailed description the keyhole evolution mechanism. • The formation process and movement mechanism of pores were revealed. In the complex laser powder bed fusion (L-PBF) process, the occurrence of pores is often triggered when localized temperatures of the materials exceed their boiling point, posing a significant impediment to the overall quality of manufactured parts. In this work, considering the thermophysical properties and latent heat of phase transformation of the material, the formation and evolution of keyholes and pores during the L-PBF single-track processing of TA15 titanium alloy was investigated using X-ray computed tomography (X-CT) and FLOW-3D finite volume analysis software coupled with multiphysics fields. The simulated molten pool characteristics generally agree with the experimental data, including internal pores The results showed that the evolution of keyholes is mainly attributed to surface tension and recoil pressure, the Marangoni flow and surface tension contributed to closed localized cooling regions on the keyhole walls to generate pores. Additionally, the Marangoni flow and buoyancy effects lead to pore motion within the molten pool. Furthermore, the laser energy density is inherently related to the total pore counts and the mean penetration depth of keyholes, respectively. Understanding the underlying physical mechanisms helps to optimize process parameters and reduce pores in L-PBF, ultimately enhancing the quality of the additively manufactured parts. [ABSTRACT FROM AUTHOR]