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.

Surface-Phosphorylated Ceria for Chlorine-Tolerance Catalysis.

An improved fundamental understanding of active site structures can unlock opportunities for catalysis from conceptual design to industrial practice. Herein, we present the computational discovery and experimental demonstration of a highly active surface-phosphorylated ceria catalyst that exhibits robust chlorine tolerance for catalysis. Ab initio molecular dynamics (AIMD) calculations and in situ near-ambient pressure X-ray photoelectron spectroscopy (in situ NAP-XPS) identified a predominantly HPO4 active structure on CeO2(110) and CeO2(111) facets at room temperature. Importantly, further elevating the temperature led to a unique hydrogen (H) atom hopping between coordinatively unsaturated oxygen and the adjacent P═O group of HPO4. Such a mobile H on the catalyst surface can effectively quench the chlorine radicals (Cl•) via an orientated reaction analogous to hydrogen atom transfer (HAT), enabling the surface-phosphorylated CeO2-supported monolithic catalyst to exhibit both expected activity and stability for over 68 days during a pilot test, catalyzing the destruction of a complex chlorinated volatile organic compound industrial off-gas.

Polymerization State of Vanadyl Species Affects the Catalytic Activity and Arsenic Resistance of the V2O5-WO3/TiO2 Catalyst in Multipollutant Control of NOx and Chlorinated Aromatics.

The conventional V2O5-WO3/TiO2 catalyst suffers severely from arsenic poisoning, leading to a significant loss of catalytic activity. The doping of Al or Mo plays an important role in promoting the arsenic resistance on NH3 selective catalytic reduction (NH3-SCR), but their promotion mechanism remains in debate and has yet to be explored in multipollutant control (MPC) of NOx and chlorinated organics. Herein, our experimental characterizations and density functional theory (DFT) calculations confirmed that arsenic species preferentially adsorb on both Al and Mo to form arsenate, thereby avoiding bonding to the catalytically active V sites. More importantly, Al doping partially converted the polymeric vanadyl species into monomeric ones, thereby inhibiting the near-surface and bulk lattice oxygen mobility of the V2O5-WO3/TiO2 catalyst, while Mo doping resulted in vanadyl polymerization with an enriched V5+ chemical state and exhibited superior MPC activity and COx selectivity. Our work shows that antipoisoning catalysts can be designed with the combination of site protection and occurrence state modification of the active species.

Selective Ru Adsorption on SnO2/CeO2 Mixed Oxides for Efficient Destruction of Multicomponent Volatile Organic Compounds: From Laboratory to Practical Possibility.

Ru-based catalysts have been extensively employed for the catalytic destruction of chlorinated volatile organic compounds (VOCs), but their versatility for other routine VOCs' destruction has been less explored. Herein, we show that Ru-decorated SnO2/CeO2 mixed oxides can sustain H2O and HCl poisonings and are endowed with extraordinary versatility for a wide range of VOCs' destruction. Selective adsorption of Ru on the cassiterite SnO2 and CeO2 nanorods through a Coulomb force can rationally tune the oxidation and dechlorination centers on decorated catalysts, where the epitaxial growth of RuOx on top of SnO2 is endowed with excellent dechlorination ability and that on CeO2 is functional as an oxidation center; the latter could also activate H2O to provide sufficient H protons for HCl formation. Our developed Ru/SnO2/CeO2 catalyst can steadily destruct mono-chlorobenzene, ortho-dichlorobenzene, trichloroethylene, dichloromethane, epichlorohydrin, N-hexane, ethyl acetate, toluene, and their mixtures at an optimum temperature of 300 °C, and its monolithic form is also functional at this temperature with few dioxins being detected in the off-gas. Our results imply that the Ru-decorated SnO2/CeO2 catalyst can meet the demands of regenerative catalytic oxidation for the treatment of a wide range of VOCs from industrial exhausts.

Automated Centrifugal Microfluidic Chip Integrating Pretreatment and Molecular Diagnosis for Hepatitis B Virus Genotyping from Whole Blood.

Point-of-care (POC) testing for nucleic acid that combines pretreatment and molecular diagnosis is crucial in analyzing complex samples such as those encountered in clinical diagnosis. Herein, we developed a centrifugal microfluidic platform, which can achieve a series of functions including separating serum and adsorbing, washing, eluting, and detecting DNA. We combined multiple signal enhancement systems including recombinase polymerase amplification (RPA), T7 transcription technology, and clustered regularly interspaced short palindromic repeat (CRISPR) technology to yield an ultrabright signal, which can avoid false-negative results. As an application, hepatitis B virus (HBV), a virus that causes global public health problems, was successfully detected and genotyped from whole blood on the automated centrifugal microfluidic platform. Compared to the traditional diagnosis process, the POC platform largely decreased the consumption of time from 3 to 1 h and the consumption of professional labor from three persons to only one. The automated centrifugal microfluidic platform integrated pretreatment and molecular diagnosis will play an essential role in clinical detection.

Novel method of boundary-free mesh parameterization.

Unless the targeted mesh is developable, metric distortion is inevitable during the process of surface mesh parameterization, thus one important objective of all involved parametric studies is to reduce the metric distortion. In order to further reduce area and angle distortion, a novel method of boundary-free mesh parameterization is presented in the paper. Firstly, the initial boundary-fixed conformal parameterization from 3D surface mesh patch to a plane is performed in the method. Then, based on the initial parameterization, the iterations of boundary-free quasi-harmonic parameterization are developed, where the tensor field is updated in each iterative step and the principal curvature direction is utilized to terminate the iteration. The solution of the novel method is convenient to calculate since it involves a series of linear systems. In our novel parameterization method, lower metric distortion and considerable efficiency have been obtained in experiments.

O2 and Ca(2+) fluxes as indicators of apoptosis induced by rose bengal-mediated photodynamic therapy in human oral squamous carcinoma cells.

OBJECTIVE: Photodynamic therapy (PDT) triggers various cellular responses and induces cell death via necrosis and/or apoptosis. This study evaluated the feasibility of using O2 and Ca(2+) fluxes as indicators of apoptosis induced by rose bengal (RB)-mediated PDT in human oral squamous carcinoma cells (Cal27 cells). METHODS: Intracellular reactive oxygen species (ROS) generation was assessed by the dichloro-dihydro-fluorescein diacetate (DCFH-DA) method. Real-time O2 and Ca(2+) flux measurements were performed using the noninvasive micro-test technique (NMT). Apoptosis of the PDT-treated cells was confirmed by 4'6-diamidino-2-phenylindole-dilactate staining. The activation of apoptosis-related molecules was examined using Western blot. We assayed the effects of the fluctuation of O2 and Ca(2+) flux in response to PDT and the apoptotic mechanism, by which ROS, O2, and Ca(2+) synergistically may trigger apoptosis in PDT-treated cells. RESULTS: Real-time O2 and Ca(2+) flux measurements revealed that these indicators were involved in the timely regulation of apoptosis in the PDT-treated cells and were activated 2 h after PDT treatment. RB-mediated PDT significantly elicited the generation of ROS by approximately threefold, which was critical for PDT-induced apoptosis. Cytochrome c and cleaved caspase-3, caspase-9 and poly ADP ribose polymerase (PARP) were overexpressed, and the data provided evidence that 2 h was considered to be the key observation time in RB-mediated PDT-induced apoptosis in Cal27 cells. CONCLUSIONS: Our collective results indicated that the effects of O2 and Ca(2+) fluxes may act as a real-time biomonitoring system of apoptosis in the RB-PDT-treated cells. Also, RB-mediated PDT can be a potential and effective therapeutic modality in oral squamous cell carcinoma.

[Expression of programmed death-1 and programmed death ligand-1 in the peripheral T-lymphocytes from patients with chronic periodontitis].

OBJECTIVE: To investigate the expression of programmed death-1 (PD-1) and programmed death ligand-1(PD-L1) in peripheral T-lymphocytes from patients with chronic periodontitis and its significance and to clarify its role in the development of chronic periodontitis. METHODS: A total of 73 subjects were included in the study and divided into three groups, chronic periodontitis(30 cases), chronic gingivitis(25 cases) and 18 healthy controls. The peripheral blood was collected and PD-1/PD-L1 expression in the surface of CD(+)4 T lymphocytes and CD(+)8 T lymphocytes was examined by flow cytometry. Blood samples from 16 chronic periodontitis patients were collected at week 0 and 6 after initial therapy for 6 weeks and PD-1 and PD-L1 expression in the surface of CD(+)4 and CD(+)8 T lymphocytes was also determined by flow cytometry. The data were statistically analyzed. RESULTS: The percentage of PD-1 expression in CD(+)4 and CD(+)8 T lymphocytes of chronic periodontitis group[(16.7 ± 5.5)%,(20.8 ± 5.1)%]and chronic gingivitis group[(14.2 ± 6.1)%,(14.5 ± 4.3)%]were higher than that of healthy controls[(9.5 ± 2.1)%, (8.1 ± 1.9)%](P < 0.05). The percentage of PD-L1 expression in CD(+)4 and CD(+)8 T lymphocytes of chronic periodontitis group[(24.2 ± 7.1)%,(15.3 ± 6.8)%]and chronic gingivitis group[(12.4 ± 6.0)%,(11.2 ± 5.5)%]were higher than that of healthy controls[(4.7 ± 1.2)%, (3.2 ± 2.3)%] (P < 0.05). The percentage of PD-1/PD-L1 expression in CD(+)4 T lymphocytes and CD(+)8 T lymphocytes of the chronic periodontitis group were significantly decreased after initial therapy(P < 0.05). CONCLUSIONS: The expression of PD-1 and PD-L1 in peripheral CD(+)4 T lymphocytes and CD(+)8 T lymphocyte of chronic periodontitis patients was up-regulated and was associated with periodontal condition. The initial therapy reduced the expression of PD-1 and PD-L1.