Tandem effect at snowflake-like cuprous sulphide interfaces for highly selective conversion of carbon dioxide to formate by electrochemical reduction

Electrochemical carbon dioxide reduction (ECR) is a commercially promising technology to resolve the energy dilemma and accomplish carbon recycling. Herein, a novel electrocatalyst has been investigated to produce formate (HCOOH) highly selectively during ECR by loading SnO2@C onto cuprous sulphide (Cu2S) to form a triplet effect at the interface. Snowflake-like Cu2S significantly enhances the local concentration of carbon dioxide (CO2) and promotes the binding of CO2 with SnO2, and the addition of carbon spheres enhances the electron transport, which is beneficial to the conversion of CO2 to HCOOH products. The snowflake-like Cu2S loaded with 1 wt% SnO2@C had an HCOOH Faraday Efficiency of 88% at -1.0 V (vs. Reversible Hydrogen Electrode, RHE), and the current density for CO2 reduction was stabilized at 15.6 mA cm-2, which was much higher than the HCOOH Faraday efficiency (FE) of 31.0% for pure Cu2S accompanied by a CO2 reduction current density of 3.9 mA cm-2. Combined investigations using in-situ Fourier transform infrared spectroscopy (FT-IR) with in-situ Raman spectra reveal that the active species is Cu+. Cu2S/1%SnO2@C can effectively promote the adsorption and activation of carbonate and inhibit the production of CO intermediates. The corresponding density functional theory (DFT) demonstrates that Cu2S/1%SnO2@C can well stabilize the HCOO* intermediate during the ECR process. The interaction between Cu2S and SnO2@C adjusts the surface electronic distribution and accelerates electron transfer, which efficiently improves CO2-to-HCOOH conversion. The result obtained from this work provides a simple and efficient electrocatalyst to enhance the HCOOH selectivity of ECR.

B(C6F5)3-catalyzed hydrogermylation of enones: a facile route to germacycles

Organogermacycles are important skeletons for medicinal chemistry and materials. Herein, we reported a B(C6F5)3 mediated domino hydrogermylation reaction of enones with dihydrogermanes, affording 21 variants of organogermacycle compounds. These germacyclic compounds were obtained in good to excellent yields (up to 99% yield) under mild reaction conditions.

Elective Nodal Irradiation vs. Involved-Field Irradiation for Stage Ⅱ-Ⅳ Cervical Esophageal Squamous Cell Carcinoma Patients Undergoing Definitive Concurrent Chemoradiotherapy: A Retrospective Propensity Study with Eight-Year Survival Outcomes

PURPOSE/OBJECTIVE(S)

Definitive concurrent chemoradiotherapy (dCCRT) is suggested as the standard treatment for cervical esophageal squamous cell carcinoma (CESCC). This retrospective propensity study compared the eight-year survival outcomes and acute treatment toxicities of these patients treated with elective nodal irradiation (ENI) versus involved-field irradiation (IFI).

MATERIALS/METHODS

Patients with stage Ⅱ-Ⅳ CESCC treated with dCCRT in our institution between January 1, 2007 and December 31, 2020 were enrolled in the study. All the patients were restaged according to the American Joint Commission (AJCC) 8th edition criteria. The propensity score matching (PSM) was used to minimize the effects of treatment selection bias and potential confounding factors including sex, age, ECOG score, clinical T stage (cT), clinical N stage (cN), clinical TNM stage (cTNM) and radiation dose between the ENI group and IFI group. Survival and the prognostic factors were evaluated.

RESULTS

The 131 eligible patients underwent ENI (60 patients, 45.8%) or IFI (71 patients, 54.2%). The median follow-up time was 95.3 months (range, 28.0-186.2 months) for all the patients. The median OS, 1-, 3-, 5-, and 8-year OS rates were 44.4 months, 87.8%, 55.5%, 39.0%, and 28.3%, respectively. After PSM, there were 49 patients in each group. The median OS, 1-, 3-, 5-, and 8-year OS rates for ENI and IFI group were 32.0 months, 83.7%, 48.9%, 38.8% and 32.4% versus 45.2 months, 89.8%, 52.7%, 38.2%, 26.6%, respectively (P = 0.984; HR 0.99, 95% CI 0.61-1.62). Similar locoregional control was obtained in both groups. The tendency of leukocytopenia and neutropenia was higher in ENI than in IFI (59.2% versus 38.8%; P = 0.068 and 30.6% versus 14.3%; P = 0.089) at the end of dCCRT.

CONCLUSION

Cervical esophageal squamous cell carcinoma patients undergoing definitive concurrent chemoradiotherapy has a satisfactory prognosis with organ conservation. The involved-field irradiation might be a better alternative owing to similar overall survival outcomes and local control with less toxicity of myelosuppression.

Self-Assembly of Bi2Sn2O7/β-Bi2O3 S-Scheme Heterostructures for Efficient Visible-Light-Driven Photocatalytic Degradation of Tetracycline

Fabrication of S-scheme heterojunctions with enhanced redox capability offers an effective approach to address environmental remediation. In this study, high-performance Bi₂Sn₂O₇/β-Bi₂O₃ S-scheme heterojunction photocatalysts were fabricated via the in situ growth of Bi₂Sn₂O₇ on β-Bi₂O₃ microspheres. The optimized Bi₂Sn₂O₇/β-Bi₂O₃ (BSO/BO-0.4) degradation efficiency for tetracycline hydrochloride was 95.5%, which was 2.68-fold higher than that of β-Bi₂O₃. This improvement originated from higher photoelectron-hole pair separation efficiency, more exposed active sites, excellent redox capacity, and efficient generation of ^·O₂ ^- and ^·OH. Additionally, Bi₂Sn₂O₇/β-Bi₂O₃ exhibited good stability against photocatalytic degradation, and the degradation efficiency remained >89.7% after five cycles. The photocatalytic mechanism of Bi₂Sn₂O₇/β-Bi₂O₃ S-scheme heterojunctions was elucidated. In this study, we design and fabricate high-performance heterojunction photocatalysts for environmental remediation using S-scheme photocatalysts.

Honeycomb-like CuO@C for electroreduction of carbon dioxide to ethylene

The electrochemical CO₂ reduction (ECR) of high-value multicarbon products is an urgent challenge for catalysis and energy resources. Herein, we reported a simple polymer thermal treatment strategy for preparing honeycomb-like CuO@C catalysts for ECR with remarkable C₂H₄ activity and selectivity. The honeycomb-like structure favored the enrichment of more CO₂ molecules to improve the CO₂-to-C₂H₄ conversion. Further experimental results indicate that the CuO loaded on amorphous carbon with a calcination temperature of 600 °C (CuO@C-600) has a Faradaic efficiency (FE) as high as 60.2% towards C₂H₄ formation, significantly outperforming pure CuO-600 (18.3%), CuO@C-500 (45.1%) and CuO@C-700 (41.4%), respectively. The interaction between the CuO nanoparticles and amorphous carbon improves the electron transfer and accelerates the ECR process. Furthermore, in situ Raman spectra demonstrated that CuO@C-600 can adsorb more adsorbed *CO intermediates, which enriches the CC coupling kinetics and promotes C₂H₄ production. This finding may offer a paradigm to design high-efficiency electrocatalysts, which can be beneficial to achieve the "double carbon goal."

Visible-light driven p-n heterojunction formed between α-Bi2O3 and Bi2O2CO3 for efficient photocatalytic degradation of tetracycline

To improve the efficiency of photocatalytic oxidative degradation of antibiotic pollutants, it is essential to develop an efficient and stable photocatalyst. In this study, a polymer-assisted facile synthesis strategy is proposed for the polymorph-controlled α-Bi₂O₃/Bi₂O₂CO₃ heterojunction retained at elevated calcination temperatures. The p-n heterojunction can effectively separate and migrate electron-hole pairs, which improves visible-light-driven photocatalytic degradation from tetracycline (TC). The BO-400@PAN-140 photocatalyst achieves the highest pollutant removal efficiency of 98.21% for photocatalytic tetracycline degradation in 1 h (λ > 420 nm), and the degradation efficiency was maintained above 95% after 5 cycles. The morphology, crystal structure, and chemical state of the composites were analysed by scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. Ultraviolet-visible diffuse reflection, transient photocurrent response, and electrochemical impedance spectroscopy were adopted to identify the charge transfer and separation efficiency of photogenerated electron-hole pairs. The EPR results verified h⁺ and ˙OH radicals as the primary active species in the photocatalytic oxidation reactions. This observation was also consistent with the results of radical trapping experiments. In addition, the key intermediate products of the photocatalytic degradation of TC over BO-400@PAN-140 were identified via high-performance liquid chromatography-mass spectrometry, which is compatible with two possible photocatalytic reaction pathways. This work provides instructive guidelines for designing heterojunction photocatalysts via a polymer-assisted semiconductor crystallographic transition pathway for TC degradation into cleaner production.

A Stable Rechargeable Aqueous Zn-Air Battery Enabled by Heterogeneous MoS2 Cathode Catalysts

Aqueous rechargeable zinc (Zn)−air batteries have recently attracted extensive research interest due to their low cost, environmental benignity, safety, and high energy density. However, the sluggish kinetics of oxygen (O2) evolution reaction (OER) and the oxygen reduction reaction (ORR) of cathode catalysts in the batteries result in the high over-potential that impedes the practical application of Zn−air batteries. Here, we report a stable rechargeable aqueous Zn−air battery by use of a heterogeneous two-dimensional molybdenum sulfide (2D MoS2) cathode catalyst that consists of a heterogeneous interface and defects-embedded active edge sites. Compared to commercial Pt/C-RuO2, the low cost MoS2 cathode catalyst shows decent oxygen evolution and acceptable oxygen reduction catalytic activity. The assembled aqueous Zn−air battery using hybrid MoS2 catalysts demonstrates a specific capacity of 330 mAh g−1 and a durability of 500 cycles (~180 h) at 0.5 mA cm−2. In particular, the hybrid MoS2 catalysts outperform commercial Pt/C in the practically meaningful high-current region (>5 mA cm−2). This work paves the way for research on improving the performance of aqueous Zn−air batteries by constructing their own heterogeneous surfaces or interfaces instead of constructing bifunctional catalysts by compounding other materials.

A label-free photoelectrochemical sensor of S, N co-doped graphene quantum dot (S, N-GQD)-modified electrode for ultrasensitive detection of bisphenol A

S, N co-doped graphene quantum dot (S, N-GQD) materials have been composited via a one-pot pattern and used as photosensitive materials to construct a label-free photoelectrochemical (PEC) sensor. The PEC experiments show an enhanced photocurrent response toward Bisphenol A (BPA) sensing due to the increased charge transfer rate and the enhanced absorption of visible light. Compared with dark conditions, the photocurrent signal (- 0.2 V vs. SCE) is greatly increased because of the effective oxidation of BPA by photogenerated holes and the rapid electron transfer of S, N-GQDs on the PEC sensing platform. Under optimal conditions linear current response to BPA is in two ranges of 0.12-5 µM and 5-40 µM. The limit of detection is 0.04 µM (S/N = 3). The designed sensor has enduring stability and admirable interference immunity. It  provides an alternative approach for BPA determination in real samples with recoveries of 99.3-103% and  RSD of 2.0-4.1%.

Facile Synthesis of Fe@C Loaded on g-C3N4 for CO2 Electrochemical Reduction to CO with Low Overpotential

Electrochemical CO₂ reduction has been acknowledged as a hopeful tactic to alleviate environmental and global energy crises. Herein, we designed an Fe@C/g-C₃N₄ heterogeneous nanocomposite material by a simple one-pot method, which we applied to the electrocatalytic CO₂ reduction reaction (ECR). Our optimized 20 mg-Fe@C/g-C₃N₄-1100 catalyst displays excellent performance for the ECR and a maximum Faradaic efficiency (FE) of 88% with a low overpotential of -0.38 V vs. RHE. The Tafel slope reveals that the first electron transfer, which involves a surface-adsorbed *COOH intermediate, is the rate-determining step for 20 mg-Fe@C/C₃N₄-1100 during the ECR. More precisely, the coordinating capability of the g-C₃N₄ framework and Fe@C species as a highly active site promote the intermediate product transmission. These results indicate that the combination of temperature adjustment and precursor optimization is key to facilitating the ECR of an iron-based catalyst.

Dynamic Core Polarization in High Harmonic Generation from Solids: The Example of MgO Crystals

Previously, the strong field processes in solids have always been explained by the single-active-electron (SAE) model with a frozen core excluding the fluctuation of background electrons. In this work, we demonstrate the strong field induced dynamic core polarization effect and propose a model for revealing its role in high harmonic generation (HHG) from solids. We show that the polarized core induces an additional polarization current beyond the SAE model based on the frozen cores. It gives a new mechanism for HHG and leads to new anisotropic structures, which are experimentally observed with MgO. Our experiments indicate that the influences of dynamic core polarization on HHG are obvious for both linearly and elliptically polarized laser fields. Our work establishes the bridge between the HHG and the dynamic changes of the effective many-electron interaction in solids, which paves the way to probe the ultrafast electron dynamics.

Photo-electrochemical detection of dopamine in human urine and calf serum based on MIL-101 (Cr)/carbon black

A new photo-electrochemical sensor based on MIL-101(Cr) MOF/carbon black (CB) is fabricated and characterized. By using differential pulse voltammetry, dopamine (DA) can be effectively detected using a photo-electrochemical MIL-101(Cr)/CB sensor under visible light. The CB acts as the electron bridge to combine with the large specific surface area and photo-catalytic feature of MOF, which contribute to the improvements of sensitivity of DA detection. The concentration of the catalyst, pH value, accumulation potential, and accumulation time were also optimized. Furthermore, the electrochemical performances of MIL-101(Cr)/CB sensor was investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), scan rate, electrochemically active surface area (ECSA), and amperometric responses. A detection limit of 0.38 nM (LOD = 3 s_b/S, s_b = 0.028) and a working range of 1 nM to 2.22 μM has been achieved. The MIL-101(Cr)/CB sensor exhibits excellent reproducibility, stability, and selectivity and also has satisfactory recovery rate for the analysis of real samples including calf serum and human urine. Graphical abstract.

Generation of isolated circularly polarized attosecond pulses by three-color laser field mixing

We propose and theoretically demonstrate a method to generate the circularly polarized supercontinuum with three-color electric fields. The three-color field is synthesized from an orthogonally polarized two-color (OTC) laser field and an infrared gating field. All driving pulse durations are extended to 40 fs. We demonstrate that the three-color field imposes curved trajectories for ionized electrons and extends the time interval between each harmonic emitting. Through adjusting intensity ratios among three components of the driving field, a nearly circular isolated attosecond pulse can be generated.

Tandem Mass Tag Labeling to Identify Proteome Changes in Beef Longissimus Lumborum and Psoas Major Muscles During Early Postmortem Period

ObjectivesLongissimus lumborum (LL) and psoas major (PM) are important muscles in beef hindquarters that exhibit variation in meat quality attributes. Postmortem metabolism (muscle-to-meat conversion) affects biochemical properties of muscles and in turn influence the meat quality. Although previous research has indicated that variation in the proteome profile of LL and PM post-rigor influences meat quality attributes such as tenderness and color stability during retail display, limited research has examined the influence of early postmortem metabolism on meat quality. Tandem mass tag (TMT) labeling is a chemical labeling approach used for accurate mass spectrometry-based quantification and identification of biological macromolecules. Therefore, the objective of this study was to use TMT labeling to examine proteome profile variation between beef LL and PM during the early postmortem period.Materials and MethodsMuscle biopsy samples were collected from carcasses (n = 4) at 45 min, 12 h, and 36 h postmortem from a commercial beef processing facility. Samples were frozen immediately in liquid nitrogen and stored at –80°C until proteomic analysis. Proteome was analyzed using TMT label containing ten different isobaric compounds with the same mass and chemical structure composed of an amine-reactive NHS-ester group, a spacer arm, and a mass reporter. After labeling and peptide fractionation, all the samples were multiplexed and ran through the Orbitrap Velos mass spectrometer equipped with a Nanospray Flex ion source to identify differentially abundant proteins. The proteins exhibiting 1.5-fold or more intensity difference and a statistical difference (P < 0.05) between LL and PM or within the muscles during the postmortem were reported as differentially abundant.ResultsSeventy differentially abundant proteins (P < 0.05) were identified from three comparisons between the muscles (31 proteins in PM 45 min vs. LL 45 min, 41 proteins in PM 12 h vs. LL 12 h, 49 proteins in PM 36 h vs. LL 36 h). However, no difference (P > 0.05) in protein expression within a muscle was observed during these time points. The differentially abundant proteins were mainly involved in oxidative phosphorylation and ATP-related transport, tricarboxylic acid cycle, NADPH regeneration, fatty acid degradation, muscle contraction, calcium signaling, chaperone activity, oxygen transport, as well as degradation of the extracellular matrix. At early postmortem, overabundant anti-apoptotic proteins in LL could cause high metabolic stability, enhanced autophagy, and delayed apoptosis, while overabundant metabolic enzymes and pro-apoptotic proteins in PM could accelerate the reactive oxygen species generation and programmed cell death.ConclusionDifferentially abundant proteins between LL and PM during the early postmortem were primarily associated with cellular metabolism and programmed cell death. The greater oxidative and color stability in LL compared to PM could be related to the increased expression of anti-apoptotic proteins and the decreased expression of metabolic enzymes and proapoptotic proteins in LL.

Supranutritional Supplementation of Vitamin E Influences the Abundance of Antioxidant Proteins in Postmortem Longissimus Lumborum from Heifers

ObjectivesVitamin E is a lipid-soluble antioxidant that can inhibit lipid oxidation and improve beef color stability. The effect of vitamin E on fresh beef color, from the standpoint of lipid oxidation-induced myoglobin oxidation, have been extensively studied. However, the influence of vitamin E on sarcoplasmic proteome profile of beef skeletal muscles is yet to be investigated. Therefore, the objective of this study was to examine the effect of dietary vitamin E on sarcoplasmic proteome of postmortem beef longissimus lumborum (LL) muscle.Materials and MethodsCrossbred heifers, managed with a GrowSafe feeding system, were fed ad libitum corn-based diet containing either no supplemental (CONT) or 1000 IU vitamin E/heifer per day (VITE) for 89 d. The animals were harvested, and carcasses were chilled. The LL muscle samples were obtained from the carcasses of nine (n = 9) VITE and nine (n = 9) CONT heifers 24 h postmortem. The muscle samples were individually vacuum-packaged and frozen at –80°C for proteome analysis. Sarcoplasmic proteome was analyzed using two-dimensional electrophoresis, employing immobilized pH gradient strips (pH 3–10; 17 cm) in the first dimension and 12% sodium dodecyl sulfate polyacrylamide gel electrophoresis in the second dimension. The gels were scanned, and the digital gel images were analyzed. The protein spots exhibiting more than 1.5-fold intensity differences (P < 0.10) between VITE and CONT were subjected to in-gel tryptic digestion and were identified by tandem mass spectrometry.ResultsFive differentially abundant spots were identified using mass spectrometry, and all the spots were over-abundant in CONT. The proteins in the differentially abundant spots were antioxidant proteins (thioredoxin-dependent peroxide reductase, peroxiredoxin-6, and serum albumin) and glycolytic enzymes (β-enolase and triosephosphate isomerase). The antioxidant proteins minimize oxidation of lipids and proteins in muscle matrix, whereas the glycolytic enzymes generate NADPH, which helps maintain the antioxidant proteins in their reduced forms.ConclusionThe strong antioxidant protection offered by vitamin E could have possibly led to less expression of antioxidant proteins as well as glycolytic enzymes that generate antioxidant metabolites in the VITE group, whereas the lack of such protection in CONT group may have led to increased expression of these proteins in the skeletal muscles.

Ractopamine-Induced Changes in the Mitochondrial Proteome of Postmortem Beef Longissimus Lumborum

ObjectivesRactopamine is a β-adrenergic agonist approved as growth promotant in beef cattle, and it increases muscle deposition while limiting fat deposition. Dietary ractopamine causes a muscle fiber shift in cattle, and the biochemistry of mitochondria in postmortem beef skeletal muscles is influenced by fiber type. Therefore, dietary ractopamine may potentially affect mitochondrial functionality. Nonetheless, the influence of ractopamine on beef skeletal muscle mitochondrial proteome has not been evaluated. Therefore, the objective of this study was to examine the effects of ractopamine on mitochondrial proteome of postmortem longissimus lumborum (LL) from beef cattle.Materials and MethodsPen-housed crossbred steers were fed either a corn-based basal diet (CON) or a diet top-dressed with Optaflexx 45 (Elanco Animal Health) to provide 400 mg of ractopamine hydrochloride/steer per day (RAC). Ractopamine was fed the last 28 d prior to the harvest. The animals were harvested, and carcasses were chilled for 24 h. The LL muscle samples were obtained from nine (n = 9) RAC and nine (n = 9) CON carcasses. Mitochondrial proteome was analyzed using two-dimensional electrophoresis, and the digital gel images were analyzed. The protein spots exhibiting more than 1.5-fold intensity differences (P < 0.10) between RAC and CON were subjected to in-gel tryptic digestion and were identified by tandem mass spectrometry.ResultsSeven differentially abundant proteins were identified in the mitochondrial proteome. Three proteins were over-abundant (P < 0.10) in RAC, whereas four spots were over-abundant in CON. The proteins over-abundant in RAC mitochondrial proteome was complement component 1 Q subcomponent-binding protein, very long-chain specific acyl-CoA dehydrogenase, and aconitate hydratase. On the other hand, ATP synthase subunit β, prohibitin, Cytochrome b-c1 complex subunit, and thioredoxin-dependent peroxide reductase were over-abundant in CON samples. The differentially abundant proteins belong to four functional groups; i.e., energy metabolism (ATP synthase subunit β, Cytochrome b-c1 complex subunit 1, and aconitate hydratase), chaperone activity (complement component 1 Q subcomponent-binding protein and prohibitin), antioxidant activity (thioredoxin-dependent peroxide reductase), and lipid metabolism (very long-chain specific acyl-CoA dehydrogenase).ConclusionDietary ractopamine impacts mitochondrial proteome in postmortem beef LL muscle and influences the abundance of proteins involved in cellular metabolism and protective mechanisms. The increased protein synthesis and leanness previously reported in ractopamine-fed cattle may be attributed to the decreased expression of enzymes involved in respiratory electron transport pathways and the increased expression of enzymes involved in lipolysis.

Monitoring Transport Behavior of Charge Carriers in a Single CdS@CuS Nanowire via In Situ Single-Particle Photoluminescence Spectroscopy

Examination of the spectral and kinetic characteristics of charge carrier recombination on nanostructured semiconductors by photoluminescence (PL) plays a significant role in understanding the photocatalytic process. Here, with an in situ single-particle PL technique, we studied the transport behavior of charge carriers in individual one-dimensional (1D) core-shell structures of CdS@CuS nanowires. Through the PL intensity changes in the single-particle PL spectroscopy, effective interfacial electron transport along the interface of CdS and CuS was observed, which contributes to the significant improvement (i.e., 13.5-fold increase) of photocatalytic H₂ production compared to that for pure CdS nanowires. The present study provides visual experimental evidence for understanding restraining of charge carrier recombination in the semiconductor.

An effective experimental method and apparatus for unsteady water vapor condensation investigation in high speed expansion flow

This paper presents an effective experimental method and system for mechanism study of unsteady water vapor condensation encountered in high speed expansion flow. We proposed an experimental method and designed a simplified expansion system to fulfill the study. Tunable diode laser absorption spectroscopy (TDLAS) and light sheet technique are integrated in the system to monitor the unsteady condensation process in a high speed expansion flow generated by the expansion system. Two near infrared water vapor absorption transitions (1395.0 nm and 1409.27 nm) and one near infrared methane absorption transition (1653.73 nm) are applied in the TDLAS measurement to measure the transient flow parameters during the condensation process. Using the experimental method, time dependent condensation processes are monitored with different expansion time scales. The light sheet results visually reveal the condensation phenomena during the expansion process, while TDLAS results quantitatively follow the condensation process. The experimental results are compared with computational fluid dynamics simulations and a good agreement between them is observed, which indicates that the presented experimental method and system is effective in investigating unsteady water vapor condensation in high speed expansion flow.

Highly efficient ethylene glycol electrocatalytic oxidation based on bimetallic PtNi on 2D molybdenum disulfide/reduced graphene oxide nanosheets

In this paper, a two-dimensional (2D) hybrid material of molybdenum disulfide (MoS₂)/reduced graphene oxide (RGO) is facilely synthesized and used as an ideal support for the deposition of Pt nanoparticles. The as-prepared Pt/MoS₂/RGO composites are further worked as electrocatalysts towards ethylene glycol oxidation reaction (EGOR). In addition, when alloying with Ni, the composite shows obvious enhancement in electrocatalytic performance for EGOR. Specifically, the optimized molar ratio of Pt to Ni is 3:1, namely Pt₃Ni/MoS₂/RGO performs the strongest current density of 2062 mA mg^-1_Pt, which is 11.1, 5.80 and 2.40 times higher than those of Pt, Pt₃Ni and Pt/MoS₂/RGO electrodes, respectively. The systematically electrochemical measurements indicate that the largely promoted electrocatalytic performances of Pt₃Ni/MoS₂/RGO are mainly attributed to the synergistic effect of Ni and Pt, and 2D sheets of MoS₂/RGO. This excellent performance indicates that the reported electrocatalytic material could be an efficient catalyst for the application in direct ethylene glycol fuel cell and beyond.

GLI-1 facilitates the EMT induced by TGF-β1 in gastric cancer

OBJECTIVE

To explore how GLI-1 affects the EMT induced by TGF-β1 in gastric cancer.

MATERIALS AND METHODS

Following 24 hours of culture of SGC-7901 cells in presence of TGF-β1, we observed the changes in morphology as well as mRNA and protein expressions of GLI-1, E-cadherin and Vimentin by RT-PCR and Western blot. Transwell assay was conducted to evaluate the changes in invasion ability of SGC-7901 cells. Then, SGC-7901 cells were co-treated with TGF-β1 and GANT 61, and changes of the above indexes were also detected using the corresponding methods.

RESULTS

In presence of TGF-β1, EMT was initiated in SGC-7901 cells EMT with increased cell invasion ability, and the mRNA and protein expressions of E-cadherin were downregulated, while those of the GLI-1 and Vimentin were upregulated. Conversely, the co-treatment of TGF-β1 and GANT 61 suppressed the increased cell invasion ability induced only by TGF-β1, and the changes in mRNA and protein expressions of these factors were abolished.

CONCLUSIONS

We found that GLI-1 facilitates the EMT induced by TGF-β1 in SGC-7901 cells, which may serve as a potential target in developing the clinical treatment of gastric cancer.

Microstructure and mechanical properties of hard Acrocomia mexicana fruit shell

Fruit and nut shells can exhibit high hardness and toughness. In the peninsula of Yucatan, Mexico, the fruit of the Cocoyol palm tree (Acrocomia mexicana) is well known to be very difficult to break. Its hardness has been documented since the 1500 s, and is even mentioned in the popular Maya legend The Dwarf of Uxmal. However, until now, no scientific studies quantifying the mechanical performance of the Cocoyol endocarp has been found in the literature to prove or disprove that this fruit shell is indeed "very hard". Here we report the mechanical properties, microstructure and hardness of this material. The mechanical measurements showed compressive strength values of up to ~150 and ~250 MPa under quasi-static and high strain rate loading conditions, respectively, and microhardness of up to ~0.36 GPa. Our findings reveal a complex hierarchical structure showing that the Cocoyol shell is a functionally graded material with distinctive layers along the radial directions. These findings demonstrate that structure-property relationships make this material hard and tough. The mechanical results and the microstructure presented herein encourage designing new types of bioinspired superior synthetic materials.

Monitoring ultrafast vibrational dynamics of isotopic molecules with frequency modulation of high-order harmonics

Molecules constituted by different isotopes are different in vibrational modes, making it possible to elucidate the mechanism of a chemical reaction via the kinetic isotope effect. However, the real-time observation of the vibrational motion of isotopic nuclei in molecules is still challenging due to its ultrashort time scale. Here we demonstrate a method to monitor the nuclear vibration of isotopic molecules with the frequency modulation of high-order harmonic generation (HHG) during the laser-molecule interaction. In the proof-of-principle experiment, we report a red shift in HHG from H₂ and D₂. The red shift is ascribed to dominant HHG from the stretched isotopic molecules at the trailing edge of the laser pulse. By utilizing the observed frequency shift, the laser-driven nuclear vibrations of H₂ and D₂ are retrieved. These findings pave an accessible route toward monitoring the ultrafast nuclear dynamics and even tracing a chemical reaction in real time.

Previous studies on high harmonic generation from molecules have been used to identify the spectral properties and orbital contributions. Here the authors measure the isotopic effects in the energy shift of the HHG spectra caused by the nuclear motion of the molecules.

Single-shot molecular orbital tomography with orthogonal two-color fields

Molecular orbital tomography (MOT) based on high-order-harmonic generation opens a way to track the molecular electron dynamics or even follow a chemical reaction. However, the real-time imaging of the evolution of electron orbitals is hampered by the multi-shot measurement of high-order harmonics. Here, we report a single-shot MOT scheme with orthogonal two-color (OTC) fields. This scheme enables the tomographic imaging of molecular orbital with single-shot measurement in experiment, owing to the two-dimensional manipulation of the electron motion in OTC fields. Our work paves the way towards tracking the molecular electron dynamics with combined attosecond temporal and sub-Ångström spatial resolutions.

Enhanced electrocatalytic ethanol oxidation reaction in alkaline media over Pt on a 2D BiVO4-modified electrode under visible light irradiation

2D BiVO₄ is extended to be a visible-light-responsive support for opening a new application of electrocatalytic ethanol oxidation reaction (EOR).

Competition-derived FRET-switching cationic conjugated polymer-Ir(III) complex probe for thrombin detection

A novel, label-free and convenient strategy for thrombin assay has been developed based on the fluorescence resonance energy transfer (FRET) from a cationic conjugated polymer (CCP) to Ir(III) complex. The energy donor (CCP) and acceptor (Ir(III) complex) were taken into close proximity through π-π stacking interaction and electrostatic interaction, leading to the occurrence of FRET. However, the introduction of the thrombin aptamer upset the status and blocked the FRET process, but afterwards the reappearance of FRET phenomenon was confirmed by the special binding interaction between aptamer and thrombin, thus achieving the quantitative detection of thrombin. This assay could detect thrombin as low concentration as about 0.05pM and provided a highly specific selectivity among other nonspecific proteins. Moreover, the strategy may allow our platform to provide similar sensitivity toward different targets in an aptamer-structure-independent manner. Furthermore, the assay can be used to detect thrombin in diluted real urine or serum samples with a satisfactory recovery, implying its great potential for rapid detection of thrombin in the clinic.

Attosecond Probing of Nuclear Dynamics with Trajectory-Resolved High-Harmonic Spectroscopy

We report attosecond-scale probing of the laser-induced dynamics in molecules. We apply the method of high-harmonic spectroscopy, where laser-driven recolliding electrons on various trajectories record the motion of their parent ion. Based on the transient phase-matching mechanism of high-order harmonic generation, short and long trajectories contributing to the same harmonic order are distinguishable in both the spatial and frequency domains, giving rise to a one-to-one map between time and photon energy for each trajectory. The short and long trajectories in H_{2} and D_{2} are used simultaneously to retrieve the nuclear dynamics on the attosecond and ångström scale. Compared to using only short trajectories, this extends the temporal range of the measurement to one optical cycle. The experiment is also applied to methane and ammonia molecules.

Enhanced photo-electrochemical response of reduced graphene oxide and C3N4 nanosheets for rutin detection

Herein, a sensitive photo-electrochemical sensor based on C₃N₄ and reduced graphene oxide nanosheets modified glassy carbon electrode (C₃N₄-RGO/GCE) has been fabricated for the detection of rutin under UV light illumination. In C₃N₄-RGO catalyst, RGO not only works as a template but also promotes electron transfer, meanwhile, C₃N₄ acts as a photocatalyst. Benefiting from the superior electron transfer capacity and efficient UV light effect of the C₃N₄-RGO catalyst, we get a photo-electrochemical sensor for the rutin detecting with a low detection limit of 1.78×10^-9molL^-1 and an excellent linear range of 5×10^-9-1.4×10^-4molL^-1. Meanwhile, the achieved C₃N₄-RGO/GCE demonstrated nice selectivity, good reproducibility as well as reliable stability. Moreover, compared with the electrochemical determination, the C₃N₄-RGO electrode provides a new way for rutin detection by photo-electrochemical method with a promising UV light responsive result.

CuI as Hole-Transport Channel for Enhancing Photoelectrocatalytic Activity by Constructing CuI/BiOI Heterojunction

In this paper, CuI, as a typical hole-transport channel, was used to construct a high-performance visible-light-driven CuI/BiOI heterostructure for photoelectrocatalytic applications. The heterostructure combines the broad visible absorption of BiOI and high hole mobility of CuI. Compared to pure BiOI, the CuI/BiOI heterostructure exhibited distinctly enhanced photoelectrocatalytic performance for the oxidation of methanol and organic pollutants under visible-light irradiation. The photogenerated electron-hole pairs of the excited BiOI can be separated efficiently through CuI, in which the CuI acts as a superior hole-transport channel to improve photoelectrocatalytic oxidization of methanol and organic pollutants. The outstanding photoelectrocatalytic activity shows that the p-type CuI works as a promising hole-transport channel to improve the photocatalytic performance of traditional semiconductors.

High Efficiency Photoelectrocatalytic Methanol Oxidation on CdS Quantum Dots Sensitized Pt Electrode

A cadmium sulfide quantum dots sensitized Pt (Pt-CdS) composite was synthesized using a solvothermal method and characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and UV-vis diffuse reflectance spectroscopy. The catalytic properties of the as-prepared electrode for methanol oxidation were evaluated by cyclic voltammetry (CV), chronoamperometry, electrochemical impedance spectrum (EIS) and photocurrent responses. The as-prepared Pt-CdS electrode displayed a significant enhancement in the electrocatalytic activity and stability for methanol oxidation in the presence of visible light irradiation. The synergistic effect of both the electro- and photocatalytic reaction contributes to this enhanced catalytic performance. Our result suggests a new paradigm to construct photoelectrocatalysts with high performance and good stability for direct methanol fuel cells with the assistance of visible-light illumination.

Efficient catalytic ozonation of bisphenol-A over reduced graphene oxide modified sea urchin-like α-MnO(2) architectures

Considering the biological deleterious effect of bisphenol-A (BPA) in water to the human beings, great efforts have been made for the elimination of this contaminant from water sources. Herein, we report a novel nanocomposite composed of three-dimensional (3D) sea urchin-like α-MnO2 nanoarchitectures and reduced graphene oxide (RGO) for the elimination of BPA in water in the presence of ozone. The synthesis of the as-prepared nanocomposite is facile, and the nanocomposites were well characterized by SEM, TEM, XRD, and Raman spectra. The as-synthesized α-MnO2/RGO nanocomposite was found to be a highly efficient catalyst to eliminate BPA from water in the presence of ozone. The intermediates of ozonzation were also detected by gas chromatography-mass spectrometry (GC-MS). Our investigation initiates a new opportunity to explore the high-performance catalysts for the removal of the organic pollutions in water.