Surface Hydrogen Bond-Induced Oxygen Vacancies of TiO2 for Two-Electron Molecular Oxygen Activation and Efficient NO Oxidation

Defect engineering can provide a feasible approach to achieving ambient molecular oxygen activation. However, conventional surface defects (e.g., oxygen vacancies, OVs), featured with the coordinatively unsaturated metal sites, often favor the reduction of O2 to •O2- rather than O22- via two-electron transfer, hindering the efficient pollutant removal with high electron utilization. Herein, we demonstrate that this bottleneck can be well discharged by modulating the electronic structure of OVs via phosphorization. As a proof of concept, TiO2 nanoparticles are adopted as a model material for NaH2PO2 (HP) modification, in which HP induces the formation of OVs via weakening the Ti-O bonds through the hydrogen bond interactions. Additionally, the formed Ti-O-P covalent bond refines the electronic structure of OVs, which enables rapid electron transfer for two-electron molecular oxygen activation. As exemplified by NO oxidation, HP-modified TiO2 with abundant OVs achieved complete NO removal with high selectivity for benign nitrate, superior to that of pristine TiO2. This study highlights a promising approach to regulate the O2 activation via an electronic structure modulation and provides fresh insights into the rational design of a photocatalyst for environmental remediation.

Highly selective synthesis of surface FeIV=O with nanoscale zero-valent iron and chlorite for efficient oxygen transfer reactions

High-valent iron-oxo species (FeIV=O) has been a long-sought-after oxygen transfer reagent in biological and catalytic chemistry but suffers from a giant challenge in its gentle and selective synthesis. Herein, we propose a new strategy to synthesize surface FeIV=O (≡FeIV=O) on nanoscale zero-valent iron (nZVI) using chlorite (ClO2-) as the oxidant, which possesses an impressive ≡FeIV=O selectivity of 99%. ≡FeIV=O can be energetically formed from the ferrous (FeII) sites on nZVI through heterolytic Cl-O bond dissociation of ClO2- via a synergistic effect between electron-donating surface ≡FeII and proximal electron-withdrawing H2O, where H2O serves as a hydrogen-bond donor to the terminal O atom of the adsorbed ClO2- thereby prompting the polarization and cleavage of Cl-O bond for the oxidation of ≡FeII toward the final formation of ≡FeIV=O. With methyl phenyl sulfoxide (PMS16O) as the probe molecule, the isotopic labeling experiment manifests an exclusive 18O transfer from Cl18O2- to PMS16O18O mediated by ≡FeIV=18O. We then showcase the versatility of ≡FeIV=O as the oxygen transfer reagent in activating the C-H bond of methane for methanol production and facilitating selective triphenylphosphine oxide synthesis with triphenylphosphine. We believe that this new ≡FeIV=O synthesis strategy possesses great potential to drive oxygen transfer for efficient high-value-added chemical synthesis.

Oxalate-Promoted SO2 Uptake and Oxidation on Iron Minerals: Implications for Secondary Sulfate Aerosol Formation

Mineral dust serves as a significant source of sulfate aerosols by mediating heterogeneous sulfur dioxide (SO2) oxidation in the atmosphere. Given that a considerable proportion of small organic acids are deposited onto mineral dust via long-range transportation, understanding their impact on atmospheric SO2 transformation and sulfate formation is of great importance. This study investigates the effect of oxalate on heterogeneous SO2 uptake and oxidation phenomenon by in situ FTIR, theoretical calculation, and continuous stream experiments, exploiting hematite (Fe2O3) as an environmental indicator. The results highlight the critical role of naturally deposited oxalate in mononuclear monodentate coordinating surface Fe atoms of Fe2O3 that enhances the activation of O2 for oxidizing SO2 into sulfate. Meanwhile, oxalate increases the hygroscopicity of Fe2O3, facilitating H2O dissociation into reactive hydroxyl groups and further augmenting the SO2 uptake capacity of Fe2O3. More importantly, other conventional iron minerals, such as goethite and magnetite, as well as authentic iron-containing mineral dust, exhibit similar oxalate-promoted sulfate accumulation behaviors. Our findings suggest that oxalate-assisted SO2 oxidation on iron minerals is one of the important contributors to secondary sulfate aerosols, especially during the nighttime with high relative humidity.

Locally Asymmetric BiOBr for Efficient Exciton Dissociation and Selective O2 Activation toward Oxidative Coupling of Amines

Two-dimensional (2D) layered photocatalysts with highly ordered out-of-plane symmetry usually display robust excitonic effects, thus being ineffective in driving catalytic reactions that necessitate unchained charge carriers. Herein, taking 2D BiOBr as a prototype model, we implement a superficial asymmetric [Br-Bi-O-Bi] stacking in the out-of-plane direction by selectively stripping off the top-layer Br of BiOBr. This local asymmetry disrupts the diagnostic confinement configuration of BiOBr to urge energetic exciton dissociation into charge carriers and further contributes to the emergence of a surface dipole field that powers the subsequent separation of transient electron-hole pairs. Distinct from the symmetric BiOBr, which activates O₂ into ¹O₂ via an exciton-mediated energy transfer, surface asymmetric BiOBr favors selective O₂ activation into ·O₂^- for a broad range of amine-to-imine conversions. Our work here not only presents a paradigm for asymmetric photocatalyst design but also expands the toolkit available for regulating exciton behaviors in semiconductor photocatalytic systems.

Photochemical Acceleration of Ammonia Production by Pt1-Ptn-TiN Reduction and N2 Activation

Stable metal nitrides (MN) are promising materials to fit the future "green" ammonia-hydrogen nexus. Either through catalysis or chemical looping, the reductive hydrogenation of MN to MN_1-x is a necessary step to generate ammonia. However, encumbered by the formation of kinetically stable M-NH_1─3 surface species, this reduction step remains challenging under mild conditions. Herein, we discovered that deleterious Ti-NH_1─3 accumulation on TiN can be circumvented photochemically with supported single atoms and clusters of platinum (Pt₁-Pt_n) under N₂-H₂ conditions. The photochemistry of TiN selectively promoted Ti-NH formation, while Pt₁-Pt_n effectively transformed any formed Ti-NH into free ammonia. The generated ammonia was found to originate mainly from TiN reduction with a minor contribution from N₂ activation. The knowledge accrued from this fundamental study could serve as a springboard for the development of MN materials for more efficient ammonia production to potentially disrupt the century-old fossil-powered Haber-Bosch process.

Hydroxyl Radical-Mediated Efficient Photoelectrocatalytic NO Oxidation with Simultaneous Nitrate Storage Using A Flow Photoanode Reactor

The selective conversion of dilute NO pollutant into low-toxic product and simultaneous storage of metabolic nitrogen for crop plants remains a great challenge from the perspective of waste management and sustainable chemistry. This study demonstrates that this bottleneck can be well tackled by refining the reactive oxygen species (ROS) on Ni-modified NH2-UiO-66 (Zr) using nickel foam (Ni@NU/NF) as a three-dimensional (3D) substrate through a flow photoanode reactor via the gas-phase photoelectrocatalysis. By rationally refining the ROS to •OH, Ni@NU/NF can rapidly eliminate 82% of NO without releasing remarkable NO2 under a low bias voltage (0.3 V) and visible light irradiation. The abundant mesoporous pores on Ni@NU/NF are conducive to the diffusion and storage of the formed nitrate, which enables the progressive conversion NO into nitrate with selectivity over 99% for long-term use. Through calculation, 90% of NO could be recovered as the nitrate species, indicating that this state-of-the-art strategy can capture, enrich and recycle the pollutant N source from the atmosphere. This study offers a new perspective of NO pollutant treatment and sustainable nitrogen exploitation, which may possess great potential to the development of highly efficient air purification systems for industrial and indoor NOx control.

Zero-valent iron coupled calcium hydroxide: A highly efficient strategy for removal and magnetic separation of concentrated fluoride from acidic wastewater

The removal of concentrated fluoride in acidic wastewater by the conventional Ca(OH)₂ method is challenged by the insufficient efficiency and difficult separation of fine CaF₂ precipitate. Herein, we construct a strategy to tackle these challenges by coupling zero-valent iron (ZVI) with Ca(OH)₂. ZVI reduces fluoride concentration from 12,000 to 3980 mg L^-1 under optimal conditions primarily through the in-situ growth of porous FeF₂·4H₂O shell on its surface, which simultaneously assists fluoride removal via adsorption. The residual fluoride after ZVI treatment then decreases to 6.74 mg L^-1 via precipitation with Ca(OH)₂. Interestingly, the iron ions dissolved from ZVI also participate in the precipitation to form magnetite. This co-precipitation reinforces the fluoride removal and meanwhile endows the resulted precipitates with magnetism, thus enabling the perfect solid-liquid separation by the magnetic field before discharge. The application prospect of this coupling strategy is further verified by its ability in decreasing the concentrations of fluoride and other coexisting heavy metals (Zn²⁺, Cd²⁺ and Pb²⁺) in real smeltery wastewater below their discharge limitations. This study provides a promising strategy for the treatment of concentrated fluoride in acidic wastewater and also highlights ZVI as a good candidate to couple with conventional methods for enhanced pollution control.

An Electrochemical Strategy for Simultaneous Heavy Metal Complexes Wastewater Treatment and Resource Recovery

Heavy metals chelated with coexisting organic ligands in wastewater impose severe risks to public health and the ambient ecosystem but are also valuable metal resources. For sustainable development goals, the treatment of heavy metal complexes wastewater requires simultaneous metal-organic bond destruction and metal resource recovery. In this study, we demonstrated that a neutral pH electro-Fenton (EF) system, which was composed of an iron anode, carbon cloth cathode, and sodium tetrapolyphosphate electrolyte (Na₆TPP), could induce a successive single-electron activation pathway of molecular oxygen due to the formation of Fe(II)-TPP complexes. The boosted •OH generation in the Na₆TPP-EF process could decomplex 99.9% of copper ethylene diamine tetraacetate within 8 h; meanwhile, the released Cu ions were in situ deposited on the carbon cloth cathode in the form of Cu nanoparticles with a high energy efficiency of 2.45 g kWh^-1. Impressively, the recovered Cu nanoparticles were of purity over 95.0%. More importantly, this neutral EF strategy could realize the simultaneous removal of Cu, Ni, and Cr complexes from real electroplating effluents. This study provides a promising neutral EF system for simultaneous heavy metal complexes wastewater treatment and resource recovery and sheds light on the importance of molecular oxygen activation in the field of pollutant control.

Singlet Oxygen and Mobile Hydroxyl Radicals Co-operating on Gas-Solid Catalytic Reaction Interfaces for Deeply Oxidizing NOx

Learning from the important role of porphyrin-based chromophores in natural photosynthesis, a bionic photocatalytic system based on tetrakis (4-carboxyphenyl) porphyrin-coupled TiO₂ was designed for photo-induced treating low-concentration NO_x indoor gas (550 parts per billion), achieving a high NO removal rate of 91% and a long stability under visible-light (λ ≥ 420 nm) irradiation. Besides the great contribution of the conventional ^•O₂^- reactive species, a synergic effect between a singlet oxygen (¹O₂) and mobile hydroxyl radicals (^•OH_f) was first illustrated for removing NO_x indoor gas (¹O₂ + 2NO → 2NO₂, NO₂ + ^•OH_f → HNO₃), inhibiting the production of the byproducts of NO₂. This work is helpful for understanding the surface mechanism of photocatalytic NO_x oxidation and provides a new perspective for the development of highly efficient air purification systems.

Vacancy-Rich and Porous NiFe-Layered Double Hydroxide Ultrathin Nanosheets for Efficient Photocatalytic NO Oxidation and Storage

An appealing strategy in the direction of circular chemistry and sustainable nitrogen exploitation is to efficiently convert NOx pollutants into low-toxic products and simultaneously provide crop plants with metabolic nitrogen. This study demonstrates that such a scenario can be realized by a defect- and morphology-coengineered Ni-Fe-layered double hydroxide (NiFe-LDH) comprising ultrathin nanosheets. Rich oxygen vacancies are introduced onto the NiFe-LDH surface, which facilitate charge carrier transfer and enable photocatalytic O₂ activation into superoxide radicals (^•O₂^-) under visible light. ^•O₂^- on NiFe-LDH thermodynamically oxidizes NO into nitrate with selectivity over 92%, thus suppressing dangerous NO₂ emissions. By merit of abundant mesopores on NiFe-LDH ultrathin nanosheets bearing a high surface area (103.08 m²/g), nitrate can be readily stored without compromising the NO oxidation reactivity or selectivity for long-term usage. The nitrate species can be easily washed off the NiFe-LDH surface and then enriched in the liquid form as easy-to-use chemicals.

Constructing asymmetric active sites on defective Ru/W18O49 for photocatalytic nitrogen fixation

Defect engineering can offer active sites for N2 adsorption and activation due to the abundant localized electron of surface defect. However, the high energy barriers of defect band can restrict...

Plasmonic O2 dissociation and spillover expedite selective oxidation of primary C-H bonds

Manipulating O₂ activation via nanosynthetic chemistry is critical in many oxidation reactions central to environmental remediation and chemical synthesis. Based on a carefully designed plasmonic Ru/TiO_2−x catalyst, we first report a room-temperature O₂ dissociation and spillover mechanism that expedites the “dream reaction” of selective primary C–H bond activation. Under visible light, surface plasmons excited in the negatively charged Ru nanoparticles decay into hot electrons, triggering spontaneous O₂ dissociation to reactive atomic ˙O. Acceptor-like oxygen vacancies confined at the Ru–TiO₂ interface free Ru from oxygen-poisoning by kinetically boosting the spillover of ˙O from Ru to TiO₂. Evidenced by an exclusive isotopic O-transfer from ¹⁸O₂ to oxygenated products, ˙O displays a synergistic action with native ˙O₂⁻ on TiO₂ that oxidizes toluene and related alkyl aromatics to aromatic acids with extremely high selectivity. We believe the intelligent catalyst design for desirable O₂ activation will contribute viable routes for synthesizing industrially important organic compounds.

Room-temperature O₂ dissociation and spillover, as driven by plasmonic Ru on oxygen-deficient TiO₂, expedite the selective oxidation of primary C–H bonds in alkyl aromatics for synthesizing industrially important organic compounds.

Kirkendall Effect Boosts Phosphorylated nZVI for Efficient Heavy Metal Wastewater Treatment

Removal of non-biodegradable heavy metals has been the top priority in wastewater treatment and the development of green technologies remains a significant challenge. We demonstrate that phosphorylated nanoscale zero-valent iron (nZVI) is promising for removal of heavy metals (Ni^II , Cu^II , Cr^VI , Hg^II ) via a boosted Kirkendall effect. Phosphorylation confines tensile hoop stress on the nZVI particles and "breaks" the structurally dense spherical nZVI to produce numerous radial nanocracks. Exemplified by Ni^II removal, the radial nanocracks favor the facile inward diffusion of Ni^II and the rapid outward transport of electrons and ferrous ions through the oxide shell for surface (Ni^II /electron) and boundary (Ni^II /Fe⁰ ) galvanic exchange. Accompanied by a pronounced hollowing phenomenon, phosphorylated nZVI can instantly reduce and immobilize Ni^II throughout the oxide shell with a high capacity (258 mg Ni g^-1  Fe). For real electroplating factory wastewater treatment, this novel nZVI performs simultaneous Ni^II and Cu^II removal, producing effluent of stable quality that meets local discharge regulations.

Skp2/p27 axis regulates chondrocyte proliferation under high glucose induced endoplasmic reticulum stress

OBJECTIVE

Diabetes mellitus is closely related to osteoarthritis (OA) and may be an independent risk factor for the development of OA. As one of the main characteristics of diabetes, endoplasmic reticulum (ER) stress resulting from glucose metabolism disorder is one of the main causes of cartilage degeneration. The aim of our study is to illuminate the effect of high glucose to chondrocytes (CHs) and the role of Skp2 in high-glucose induced ER stress in CHs.

PATIENTS AND METHODS

We compared the ER stress status between healthy and diabetic OA cartilage using Western blot and quantitative reverse-transcription polymerase chain reaction (RT-PCR) methods. Different concentration of glucose was used to culture CHs for both 24 h and 72 h. Furthermore, Tunicamycin (TM) and 4-Phenylbutyric acid (4-PBA) were used to mediate ER stress of CHs, and human recombinant Skp2 protein was used to promote Skp2 expression. CH viability was determined by CCK8 assay, and cell proliferation was determined by flow cytometry. Western and RT-PCR were performed to measure related gene expression.

RESULTS

ER stress makers GADD34, GRP78, and MANF were upregulated in diabetic OA cartilage. The long-term high glucose increased GADD34, GRP78, and MANF expression, but decreased collagen II and proliferation of CHs, and Skp2 expression was negative related to the ER stress level. Additionally, Skp2 overexpression partly reversed ER stress-induced collagen II and proliferation suppression by the suppression of p27 expression.

CONCLUSIONS

High glucose raises the ER stress in CHs and overexpression of Skp2 promotes CH proliferation under high glucose treatment.

Ultrafast Microwave Polarizing Electrons to Form Vertically Aligned Metal Hybrids as Lithiophilic Buffer for Lithium-Metal Batteries

Lithium-metal batteries (LMBs) have attracted great attention because of their high theoretical capacity and low electrochemical potential. However, uncontrollable Li dendrite growth and significant volume expansion result in safety issues that largely limit their practical applications. Herein, we explore a microwave-assisted strategy for the rapid synthesis of vertically aligned metal hybrids on Cu foil (VAMH@CF). Such an elaborate architecture of VAMH provides a lithiophilic buffer layer after prelithiation, offering vast nucleation sites/seeds for Li deposition (Li@VAMH@CF) and lower nucleation overpotential. Consequently, Li@VAMH@CF exhibits an outstanding cyclability with a long lifespan (up to 5500 cycles) and a low voltage hysteresis (28 mV) in a symmetrical cell at 3 mA cm^-2. LiFePO₄||Li@VAMH@CF full cells deliver a reversible capacity of about 140 mAh g^-1 for 200 cycles, further demonstrating opportunities of the microwave-involved strategy for optimizing Li-metal anodes.

Dual-function surface hydrogen bonds enable robust O2 activation for deep photocatalytic toluene oxidation

Extensive hydrogen-bonds between the hydroxyl-rich BiOCl surface and phosphoric acid significantly facilitate oxygen vacancy formation, O₂ activation, and deep toluene oxidation.

Surface hydrogen bond network spatially confined BiOCl oxygen vacancy for photocatalysis

Rational engineering of oxygen vacancy (V_O) at atomic precision is the key to comprehensively understanding the oxygen chemistry of oxide materials for catalytic oxidations. Here, we demonstrate that V_O can be spatially confined on the surface through a sophisticated surface hydrogen bond (HB) network. The HB network is constructed between a hydroxyl-rich BiOCl surface and polyprotic phosphoric acid, which remarkably decreases the formation energy of surface V_O by selectively weakening the metal-oxygen bonds in a short range. Thus, surface-confined V_O enables us to unambiguously distinguish the intrafacial and suprafacial oxygen species associated with NO oxidation in two classical catalytic systems. Unlike randomly distributed bulk V_O that benefits the thermocatalytic NO oxidation and lattice O diffusion by the dominant intrafacial mechanism, surface V_O is demonstrated to favor the photocatalytic NO oxidation through a suprafacial scheme by energetically activating surface O₂, which should be attributed to the spatial confinement nature of surface V_O.

Over-expression of DJ-1 attenuates effects of curcumin on colorectal cancer cell proliferation and apoptosis

OBJECTIVE

The phosphatase and tensin homologue deleted on chromosome ten (PTEN) acts as a tumor suppressor gene by inhibiting the phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) signaling pathway. DJ-1, a negative regulator of PTEN, is associated with the pathogenesis of a variety of tumors. Curcumin (Cur) is a phenolic compound that is extracted from various plant rhizomes with various anti-tumor pharmacological effects. This study aimed to investigate the effects of Cur on proliferation and apoptosis of colorectal cancer cells.

MATERIALS AND METHODS

Human normal colorectal epithelial cell line (NCM460) and colorectal cancer cell line (SW480 and SW620) were cultured in vitro. Real-time quantitative PCR (RT-PCR) and western blot were used to detect DJ-1 and PTEN mRNA and protein, respectively. Cell apoptosis was determined with flow cytometry. SW480 cells were divided into control, 20 μM Cur treatment group, Cur+pcDNA3.1-Blank group and Cur+pcDNA3.1-DJ-1 group. Cell proliferation activity was evaluated with EdU staining.

RESULTS

Comparing with NCM460 cells, DJ-1 was significantly increased, while PTEN was significantly declined in SW480 and SW620 cells (p<0.05). Cur treatment significantly inhibited SW480 and SW620 cell proliferation and significantly induced apoptosis compared to control group (p<0.05) but showed no significant effects on NCM460 cells. Cur down-regulated DJ-1 level and enhanced PTEN expressions in SW480 cells with dose dependence. The pcDNA3.1-DJ-1 transfection significantly declined PTEN expression, enhanced p-AKT levels, reduced cell apoptosis, and strengthened cell proliferation in SW480 cells treated by Cur (p<0.05).

CONCLUSIONS

Cur can inhibit colorectal cancer cell proliferation and promote apoptosis by down-regulating DJ-1 expression to regulate the activity of PTEN/PI3K/AKT signaling pathway.

Over-expression of DJ-1 attenuates effects of curcumin on colorectal cancer cell proliferation and apoptosis

Since this article has been suspected of research misconduct and the corresponding authors did not respond to our request to prove originality of data and figures, "Over-expression of DJ-1 attenuates effects of curcumin on colorectal cancer cell proliferation and apoptosis, by H. Shang, T. Wang, F. Shang, M. Li, Y. Luo, K.-M. Huang, published in Eur Rev Med Pharmacol Sci 2019; 23 (7): 3080-3087-DOI: 10.26355/eurrev_201904_17591-PMID: 31002157" has been withdrawn. The Publisher apologizes for any inconvenience this may cause. https://www.europeanreview.org/article/17591.

PARP inhibitors as maintenance therapy in newly diagnosed advanced ovarian cancer: a meta-analysis

BACKGROUND

Up to 70% of patients with advanced ovarian cancer have a relapse after primary therapy. New agents and approaches are urgently needed to avoid or slow down this recurrence.

OBJECTIVES

To investigate the efficacy of PARP inhibitors (PARPis) as maintenance treatment in patients with newly diagnosed advanced ovarian cancer.

SEARCH STRATEGY

PubMed, MEDLINE, EMBASE, Cochrane Library and Web of Science databases.

SELECTION CRITERIA

All randomised clinical trials (RCTs) that compared PARPis with placebo as first-line maintenance therapy in ovarian cancer.

DATA COLLECTION AND ANALYSIS

Two reviewers extracted data. Pooled hazard ratio (HR) and risk ratio (RR) with 95% confidence interval (CI) were calculated.

MAIN RESULTS

PARPis were associated with significant improvement of progression-free survival (PFS) in advanced epithelial ovarian cancer (AeOC) (HR = 0.53, 95% CI 0.40-0.71; P < 0.0001). The benefit was not only in women with BRCA mutations (HR = 0.35, 95% CI 0.29-0.42; P < 0.00001) and homologous recombination deficiency (HRD) (HR = 0.43, 95% CI 0.32-0.60; P < 0.00001), but also in those with nonmutated BRCA (HR = 0.72, 95% CI 0.63-0.82; P < 0.00001) and even non-HRD (HR = 0.83, 95% CI 0.70-0.99; P = 0.04).

CONCLUSIONS

PARP inhibitors are effective as maintenance therapy among patients with newly diagnosed advanced ovarian cancer after platinum-based chemotherapy, regardless of BRCA mutation or HRD status.

TWEETABLE ABSTRACT

PARPis provide a significant PFS benefit as first-line maintenance therapy in patients with newly diagnosed advanced ovarian cancer.

Atomic-Scale Tuning of Graphene/Cubic SiC Schottky Junction for Stable Low-Bias Photoelectrochemical Solar-to-Fuel Conversion

Engineering tunable graphene-semiconductor interfaces while simultaneously preserving the superior properties of graphene is critical to graphene-based devices for electronic, optoelectronic, biomedical, and photoelectrochemical applications. Here, we demonstrate this challenge can be surmounted by constructing an interesting atomic Schottky junction via epitaxial growth of high-quality and uniform graphene on cubic SiC (3C-SiC). By tailoring the graphene layers, the junction structure described herein exhibits an atomic-scale tunable Schottky junction with an inherent built-in electric field, making it a perfect prototype to systematically comprehend interfacial electronic properties and transport mechanisms. As a proof-of-concept study, the atomic-scale-tuned Schottky junction is demonstrated to promote both the separation and transport of charge carriers in a typical photoelectrochemical system for solar-to-fuel conversion under low bias. Simultaneously, the as-grown monolayer graphene with an extremely high conductivity protects the surface of 3C-SiC from photocorrosion and energetically delivers charge carriers to the loaded cocatalyst, achieving a synergetic enhancement of the catalytic stability and efficiency.

Inhibition of microRNA-875-5p promotes radioiodine uptake in poorly differentiated thyroid carcinoma cells by upregulating sodium-iodide symporter

BACKGROUND AND AIM

Poorly differentiated thyroid carcinoma (PDTC) is an endocrine malignancy that is challenging to treat due to its limited radioiodine uptake. microRNAs (miRNAs or miRs) have been shown to be useful in treating many types of tumors, including PDTC. This study aims to evaluate the potential effect of miR-875-5p on the radioiodine uptake of PDTC and to clarify the underlying mechanisms.

METHODS

Expression of miR-875-5p and sodium-iodide symporter (NIS) in tissues and cell lines was determined using RT-qPCR. The binding relationship between miR-875-5p and NIS was predicted through in silico analysis and verified by dual-luciferase reporter gene assay. A series of miR-875-5p mimic, miR-875-5p inhibitor, shRNA against NIS, and overexpressed NIS plasmids were introduced into PDTC cells. We then evaluated the cell viability, colony formation, apoptosis, and radioiodine uptake of each PDTC sample via CCK-8 assay, clonogenic assay, flow cytometry, and γ counter, respectively.

RESULTS

miR-875-5p was found to be highly expressed, but NIS was poorly expressed in DTC tissues and PDTC cell lines. NIS was verified to be a target gene of miR-875-5p. Upregulation of miR-875-5p was found to induce PDTC cell proliferation, and reduce apoptosis and radioiodine uptake in vitro through down-regulation of NIS. In an in vivo orthotopic model, the enhancement of miR-875-5p led to the reduction of NIS expression and radioiodine uptake in the thyroid tumors.

CONCLUSIONS

Altogether, the findings of the current study suggest that down-regulated miR-875-5p expression could promote its target gene NIS to increase radioiodine uptake in PDTC, constituting a preventive strategy against PDTC.

Photochemical behavior of ferrihydrite-oxalate system: Interfacial reaction mechanism and charge transfer process

Heterogeneous photochemical reactions associated with natural iron (hydr)oxides and oxalic acid have attracted a great deal of scientific attention in the application of organic pollutants degradation. However, the reaction mechanism is still unclear due to the complicated iron cycles and reactive oxygen species (ROS) generation. In this study, the in situ attenuated total reflectance-Fourier transform infrared spectroscopy was implemented to investigate the adsorption process and photochemical behavior of oxalic acid on the surface of ferrihydrite. A comprehensive reaction mechanism from the perspective of charge transfer process, including homogeneous-heterogeneous iron cycling and ROS generation, was illustrated in detail. We found that oxalic acid was first adsorbed on the surface of ferrihydrite with a mononuclear bidentate binding geometry. Interestingly, this mononuclear bidentate complex on the surface of ferrihydrite was stable under visible light irradiation. Subsequently, the whole complex departed from ferrihydrite surface through non-reduction dissolution with the form of Fe(C₂O₄)⁺. In the solution, the Fe(C₂O₄)⁺ complexes would quickly convert to Fe(C₂O₄)₂^- complexes. Under visible light irradiation, the electrons generated from the photolysis of Fe(C₂O₄)₂^- complex reacted with O₂ to form O₂^•-/•OOH. Meanwhile, Fe(III) was reduced to Fe(II). Finally, the produced O₂^•-/•OOH could react with Fe(II) through a one-step way to generate •OH, which possessed higher •OH formation efficiency than that through the two-step way of H₂O₂ as the intermediates. This study helps us with understanding of in-situ photochemical reaction mechanism of ferrihydrite-oxalic acid system, and also provides guidance to effectively utilize widespread iron (hydr)oxides and organic acids in natural environment to develop engineered systems for water treatment.

Interfacial Charging-Decharging Strategy for Efficient and Selective Aerobic NO Oxidation on Oxygen Vacancy

Intelligent defect engineering to harness surface molecular processes is at the core of selective oxidation catalysis. Here, we demonstrate that the two-electron-trapped oxygen vacancy (V_O) of BiOCl, a prototypical F center (V_Ő''), is a superb site to confine O₂ toward efficient and selective NO oxidation to nitrate. Stimulated by solar light, V_Ő'' accomplishes NO oxidation through a two-electron charging (V_Ő'' + O₂ → V_Ő''-O₂^2-) and subsequent one-electron decharging process (V_Ő''-O₂^2- + NO → V_O-NO₃^- + e^-). The back-donated electron is retrapped by V_O to produce a new single-electron-trapped V_O (V_O'), simultaneously triggering a second round of NO oxidation (V_O'-O₂ + NO → V_O-NO₃^-). This unprecedented interfacial charging-decharging scheme alters the peroxide-associated NO oxidation selectivity from NO₂ to NO₃^- with a high efficiency and thus hold great promise for the treatment of risky NO _x species in indoor air.

Oxygen Vacancies Promoted the Selective Photocatalytic Removal of NO with Blue TiO2 via Simultaneous Molecular Oxygen Activation and Photogenerated Hole Annihilation

Semiconductor photocatalytic technology has great potential for the removal of dilute gaseous NO in indoor and outdoor atmospheres but suffers from unsatisfactory NO-removal selectivity due to undesirable NO₂ byproduct generation. In this study, we demonstrate that the 99% selectivity of photocatalytic NO oxidation toward nitrate can be achieved over blue TiO₂ bearing oxygen vacancies (OVs) under visible-light irradiation. First-principles density functional theory calculation and experimental results suggested that the OVs of blue TiO₂ with localized electrons could facilitate the molecular oxygen activation through single-electron pathways to generate ·O₂^- and simultaneously promote the photogenerated hole annihilation. The generated ·O₂^- directly converted NO to nitrate, while the hole annihilation inhibited the side-reaction between holes and NO to avoid toxic NO₂ byproduct formation, resulting in the highly selective removal of NO. This study reveals the dual functions of OVs in defective photocatalysts and also provides fundamental guidance for the selective purification of NO with photocatalytic technology.

[Factors related to antiretroviral therapy among HIV/AIDS positive students aged 15-30, in a hospital of Shenyang city]

Objective: To investigate the risk factors on antiretroviral therapy (ART) among HIV/AIDS positive students in Shenyang. Methods: A cross-sectional study was conducted among HIV/AIDS positive students aged between 15 and 30, in an HIV-treatment-designated hospital in Shenyang city, during 2007-2015. Data were analyzed by multivariate logistic regression mode to identify the risk factors related to ART. Results: A total of 2 379 HIV/AIDS patients attended the hospital and 6.1% (146/2 379) of them were students, during 2007-2015. All of the HIV/AIDS positive students were males, with homosexual transmission accounted for 93.2% (136/146). The overall rate on delayed diagnosis was 52.7% (77/146), when at diagnosis of CD(4)(+)T lymphocyte counts ≤350 cells/μl. The proportion of ART was 67.1% (98/146). Factors as: year that the HIV diagnosis was made (aOR=1.21, 95%CI: 1.02-1.44), age between 24-30 (compared with age below 18-year-old, aOR=8.15, 95%CI: 1.46-45.52), and delayed diagnosis (aOR=2.22, 95%CI: 1.05-4.71), appeared independently related to ART among HIV/AIDS positive students. Conclusions: Factors as the year that HIV diagnosis was made, age and delayed diagnosis of the patients seemed to be at higher risk for ART among HIV/AIDS positive students.

Effects of oat protein supplementation on skeletal muscle damage, inflammation and performance recovery following downhill running in untrained collegiate men

The positive influence of animal-based protein supplementation during muscle-damaging exercise has been widely studied. However, the effects of plant-based proteins remain unclear and require further clarification. This study investigated the protective role of oat protein against exercise induced muscle damage (EIMD), subsequent inflammation, and loss of performance induced by downhill running. Subjects consumed either oat protein (25 g protein) or a placebo for 14 days prior to a downhill running test and then for 4 days thereafter. Treatments with oat protein for 19 days markedly alleviated eccentric exercise induced skeletal muscle soreness, and reduced the elevation of plasma IL-6 concentrations and serum creatine kinase, myoglobin and C reactive protein contents. In addition, oat protein supplementation significantly inhibited limb edema following damaging exercise, and the adverse effects on muscle strength, knee-joint range of motion, and vertical jump performance were lessened. Furthermore, the administration of oat protein facilitated recovery from exhaustive downhill running in this study. These findings demonstrated that oat protein supplementation has the potential to alleviate the negative effects of eccentric exercise in untrained young males.

Visible Light Driven Organic Pollutants Degradation with Hydrothermally Carbonized Sewage Sludge and Oxalate Via Molecular Oxygen Activation

Converting sewage sludge into functional environmental materials has become an attractive sewage sludge disposal route. In this study, we synthesize a sewage sludge-based material via a facile one-pot hydrothermal carbonization method and construct a visible light molecular oxygen activation system with hydrothermally carbonized sewage sludge (HTC-S) and oxalate to degrade various organic pollutants. It was found that iron species of HTC-S could chelate with oxalate to generate H₂O₂ via molecular oxygen activation under visible light, and also promote the H₂O₂ decomposition to produce ^•OH for the fast organic pollutants degradation. Taking sulfadimidine as the example, the apparent degradation rate of HTC-S/oxalate system was almost 5-20 times that of iron oxides/oxalate system. This outstanding degradation performance was attributed to the presence of iron-containing clay minerals in HTC-S, as confirmed by X-ray diffraction measurements and Mössbauer spectrometry. In the oxalate solution, these iron-containing clay minerals could be excited more easily than common iron oxides under visible light, because the silicon species strongly interacted with iron species in HTC-S to form Fe-O-Si bond, which lowered the excitation energy of Fe-oxalate complex. This work provides an alternative sewage sludge conversion pathway and also sheds light on the environmental remediation applications of sewage sludge-based materials.

New opportunities for efficient N2 fixation by nanosheet photocatalysts

Catalytic ammonia synthesis from dinitrogen (N2) under mild conditions has been considered to be the "holy grail" of N2 fixation, which is one of the most important chemical processes in the agriculture, biological and industrial fields. Given that current artificial N2 fixation is still dominated by the energy-intensive Haber-Bosch process, solar N2 fixation represents an encouraging and fascinating route for carbon-free and energy-saving N2 fixation. However, its practical application is seriously hampered by surface sluggish reaction kinetics. In this minireview, we share our perspectives on the use of two-dimensional (2D) nanosheets for the manipulation of photocatalytic N2 fixation. Nanosheet photocatalysts serve as the perfect platform for the engineering of surface active sites, including defects and iron, all of which can not only bolster photon-exciton interaction toward robust charge carriers generation upon light absorption, but also mimic the function schemes of MoFe-cofactor in nitrogenase toward sufficient N2 binding and activation. These merits endowed by nanosheets photocatalysts provide instructive information on exploring the rich nitrogen photochemistry on solid surfaces and offer new opportunities for the design of novel photocatalysts towards efficient N2 fixation.

Oxygen Vacancies Mediated Complete Visible Light NO Oxidation via Side-On Bridging Superoxide Radicals

It is of a great challenge to seek for semiconductor photocatalysts with prominent reactivity to remove kinetically inert dilute NO without NO₂ emission. In this study, complete visible light NO oxidation mediated by O₂ is achieved over a defect-engineered BiOCl with selectivity exceeding 99%. Well-designed oxygen vacancies on the prototypical (001) surface of BiOCl favored the possible formation of geometric-favorable superoxide radicals (•O₂^-) in a side-on bridging mode under ambient condition, which thermodynamically suppressed the terminal end-on •O₂^- associated NO₂ emission in case of higher temperatures, and thus selectively oxidized NO to nitrate. These findings can help us to understand the intriguing surface chemistry of photocatalytic NO oxidation and design highly efficient NO _x removal systems.

HIV incidence is rapidly increasing with age among young men who have sex with men in China: a multicentre cross-sectional survey

OBJECTIVES

The HIV epidemic is worsening among men who have sex with men (MSM) in China, especially among those who are younger than 25 years old [younger MSM (YMSM)]. The aim of the study was to compare the prevalences of HIV incidence and recent HIV infection as well as factors associated with recent HIV infection in YMSM and older MSM (OMSM).

METHODS

A multicentre cross-sectional survey was conducted among 4496 MSM recruited from seven Chinese cities. YMSM were defined as those aged < 25 years. Data on demographics and sexual behaviours were collected using structural questionnaires. Blood samples were tested for recent HIV infection and other sexually transmitted infections.

RESULTS

Among the participants, 1313 were YMSM and 3183 were OMSM. Compared with OMSM, YMSM had a higher prevalence of recent HIV infection [5.4% (71 of 1313) for YMSM vs. 3.6% (115 of 3175) for OMSM; P = 0.006] and a higher HIV incidence [11.8 per 100 person-years (PY) (95% confidence interval (CI) 9.0-14.5) for YMSM vs. 7.6 per 100 PY (95% CI 6.3-9.0) for OMSM]. The incidence increased with age among YMSM, especially between the ages of 16 and 21 years. In contrast, the incidence declined with age among OMSM. Anal bleeding, recreational drug use, syphilis and herpes simplex virus 2 (HSV-2) infection were independent risk factors for recent HIV infection among YMSM. The prevalence of all these risk factors increased with age between the ages of 16 and 21 years. Anal bleeding (19.8%) and recreational drug use (19.5%) had the highest adjusted population attributable fractions (aPAFs) among YMSM. The highest aPAFs of anal bleeding (27.4%) and syphilis infection (25.5%) were found between the ages of 19 and 21 years.

CONCLUSIONS

The HIV incidence in Chinese YMSM was significantly higher than that in OMSM. YMSM aged 16-21 years had an extremely high risk of recent HIV infection.

A potential strategy for counteracting age-related sarcopenia: preliminary evidence of combined exercise training and leucine supplementation

Previous research has demonstrated the positive effects of concurrent/combined aerobic and resistance exercise or leucine supplementation on skeletal muscle protein synthesis (MPS) and hypertrophy in aging organisms. However, the effects of a multimodal intervention which combines both aerobic and resistance exercise and leucine supplementation has not been fully elucidated. Eighteen month old and 2 month old C57BL/6 mice were assigned to aging control (AC, n = 8), aging and multimodal intervention (AMI, n = 8) and young control (YC, n = 8). Mice in the YC and AC groups were fed an alanine-rich diet (3.4%), and mice in the AMI group received an isonitrogenous leucine-supplemented (5%) diet in combination with combined aerobic (30 minutes swimming) and resistance exercise training (incremental jumping submersed in water with overload corresponding to 40%-50% body weight) for a total of 4 weeks. The gastrocnemius muscles were dissected for western blotting detection (signaling proteins involved in MPS) and the ex vivo determination of protein synthesis and protein content. The muscle strength of the hind limbs was measured pre-experiment and repeated once per week on Sunday for 4 weeks. Mice in the AC and AMI groups showed lower ex vivo protein synthesis, protein content, expression of signaling proteins involved in MPS, maximal grip strength but higher plasma cortisol compared with the YC group post intervention. When compared to AC mice, the multimodal treatment led to lower activity of Sestrin2, higher expression of PI3K III and the phosphorylation of mTOR, p70S6K and 4E-BP1, as well as higher plasma leucine, wet gastrocnemius muscle weight and muscle weight to body weight ratio. Furthermore, the multimodal intervention induced more pronounced anabolic response such as higher ex vivo protein synthesis rate, total protein content, and myofibrillar fractions in gastrocnemius muscle, and greater maximum grip strength. The present research shows that a multimodal intervention including combined both aerobic and resistance exercise training and 5% leucine supplementation has the potential to maintain skeletal muscle protein synthesis and attenuate losses in muscular strength during the aging process.