Highly efficient and stable catalysts-covalent organic framework-supported palladium particles for 4-nitrophenol catalytic hydrogenation.

A covalent organic framework (COF) was used as the support of the catalyst in this work in order to obtain an environmentally friendly catalyst with high catalytic performance, selectivity and stability for 4-nitrophenol hydrogenation. Pd tiny particles are fixed in the cavity of COF to obtain Pd/COF catalysts, which has a quite narrow particle size distribution (5.09 ± 1.30 nm). As-prepared Pd/COF catalysts (Pd loading-2.11 wt%) shows excellent catalytic performance (conversion - 99.3%, selectivity >99.0% and turnover frequency (TOF)-989.4 h-1) for 4-nitrophenol hydrogenation under relatively mild reaction conditions of reaction temperature-40 °C and reaction pressure-3.0 MPa H2, and Pd/COF catalysts have high stability. Pd/COF catalysts were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscope energy-dispersive X-ray spectroscopy (SEM-EDS), transmission electron microscope (TEM), high resolution TEM (HRTEM), Brunauer-Emmett-Teller (BET), scanning TEM energy-dispersive X-ray spectroscopy (STEM-EDS) elemental analysis techniques to prove that the Pd nanoparticles are highly dispersed on the COF. Pd/COF catalysts have good stability and reusability hence with certain industrial application value.

Revealing the Role of Interfacial Properties on Catalytic Behaviors by in Situ Surface-Enhanced Raman Spectroscopy.

Insightful understanding of how interfacial structures and properties affect catalytic processes is one of the most challenging issues in heterogeneous catalysis. Here, the essential roles of Pt-Au and Pt-oxide-Au interfaces on the activation of H2 and the hydrogenation of para-nitrothiophenol (pNTP) were studied at molecular level by in situ surface-enhanced Raman spectroscopy (SERS) and shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS). Pt-Au and Pt-oxide-Au interfaces were fabricated through the synthesis of Pt-on-Au and Pt-on-SHINs nanocomposites. Direct spectroscopic evidence demonstrates that the atomic hydrogen species generated on the Pt nanocatalysts can spill over from Pt to Au via the Pt-Au and Pt-TiO2-Au interfaces, but would be blocked at the Pt-SiO2-Au interfaces, leading to the different reaction pathways and product selectivity on Pt-on-Au and Pt-on-SHINs nanocomposites. Such findings have also been verified by the density functional theory calculation. In addition, it is found that nanocatalysts assembled on pinhole-free shell-isolated nanoparticles (Pt-on-pinhole-free-SHINs) can override the influence of the Au core on the reaction and can be applied as promising platforms for the in situ study of heterogeneous catalysis. This work offers a concrete example of how SERS/SHINERS elucidate details about in situ reaction and helps to dig out the fundamental role of interfaces in catalysis.

[Micro-FTIR mapping tracer for the heterogeneity growth of nitrogen impurities in natural diamond from three localities in China].

The geographic locality determination of diamonds is of great significance in understanding the mantle evolution, restricting the illegal trade of conflict diamonds, etc. In the present article, the in-situ analysis of micro-FTIR surface scan technique was first applied to analyze 14 IaAB natural diamond specimens from China's three commercial localities. According to the FTIR spectra of diamonds, the nitrogen contents were calculated (1616 data points of FTIR) and used for mapping tracer. Th results showed that the nitrogen contents and its aggregation often varied in the process of diamond growth, and the nitrogen contents in initial nucleation stage could be higher or lower than in other stages. It is not an unidirectional variation for nitroge contents in different growth stages, indicating that the carbon and nitrogen had a complex exchange with mantle fluid during the diamond's crystallization course. It was regionally different between the diamonds from the three localities in the frequency distribution of nitrogen contents and NB%/N(T). Micro-FTIR mapping is more intuitive than the method of selecting discontinuous points, and it can trace the heterogeneous growth of nitrogen impurities in natural diamonds consecutively.

Survival Outcomes of Lobectomy Versus Segmentectomy in Clinical Stage I Non-Small Cell Lung Cancer: A Meta-Analysis.

INTRODUCTION: The gold standard surgical therapy for patients with clinical stage I non-small cell lung cancer (NSCLC) is lobectomy with mediastinal lymph node dissection. Meanwhile, segmentectomy has emerged as an alternative choice with the advantage of fewer postoperative complications. The acceptance of this procedure remains controversial, and conflicting results exist in the retrospective trials. OBJECTIVES: The aim of this meta-analysis was to analyze the survival outcomes of lobectomy versus segmentectomy in clinical stage I NSCLC. METHODS: A computerized literature search was done on published trials in PubMed, Embase, and the Cochrane Library to June 2019 to identify clinical trials. Lung cancer-specific survival (LCSS) and overall survival (OS) were measured as outcomes. Statistical analysis was performed in the Meta-analysis Revman 5.3 software. RESULTS: A systematic literature search was conducted including seven studies. In this meta-analysis, the LCSS and OS in the lobectomy group were linked to a markedly lower trend in comparison to the segmentectomy group without significant statistical difference (P > 0.05), indicating that lobectomy confers an equivalent survival outcome compared with segmentectomy. CONCLUSION: No significant differences were found in survival outcomes between lobectomy and segmentectomy. Further large-scale, prospective, randomized trials are needed to explore reasonable surgical treatments for early-stage lung cancer.

Insights into the role of nanoalloy surface compositions toward catalytic acetone hydrogenation.

A significant composition-dependent catalysis behavior was observed in catalytic acetone hydrogenation. Carbon supported PtRu alloy nanoparticles (NPs) with optimal surface composition achieved ultra-efficient and highly selective production of isopropyl alcohol.

Early prediction of survival in hepatocellular carcinoma patients treated with transarterial chemoembolization plus sorafenib.

AIM: To identify clinical biomarkers that could early predict improved survival in patients with advanced-stage hepatocellular carcinoma (HCC) treated with transarterial chemoembolization combined with sorafenib (TACE-S). METHODS: We retrospectively evaluated the medical records of consecutive patients with advanced-stage HCC who underwent TACE-S from January 2012 to December 2015. At the first follow-up 4-6 wk after TACE-S (median, 38 d; range, 33-45 d), patients exhibiting the modified Response Evaluation Criteria in Solid Tumors (mRECIST)-evaluated complete response, partial response, and stable disease were categorized as early disease control. At this time point, multiple variables were analyzed to identify the related factors affecting survival. RESULTS: Ninety-five patients were included in this study, and 60 of these patients achieved early disease control, with an overall disease control rate (DCR) of 63.2%. Patients who got sorafenib at the first TACE (no previous TACE) and patients without portal vein tumor thrombus (PVTT) had a higher DCR than those who underwent previous TACE before TACE-S (72.4% vs 48.6%, P = 0.019) and those with PVTT (75.5% vs 50.0%, P = 0.010). Early disease control after TACE-S, no previous TACE, and no PVTT were the independent prognostic factors for survival in the uni- and multivariate analyses. CONCLUSION: The first follow-up 4-6 wk after TACE-S can be used as the earliest time point to assess the response to TACE-S, and patients with mRECIST-evaluated early disease control, no previous TACE, and no PVTT had better survival.

In situ dynamic tracking of heterogeneous nanocatalytic processes by shell-isolated nanoparticle-enhanced Raman spectroscopy.

Surface molecular information acquired in situ from a catalytic process can greatly promote the rational design of highly efficient catalysts by revealing structure-activity relationships and reaction mechanisms. Raman spectroscopy can provide this rich structural information, but normal Raman is not sensitive enough to detect trace active species adsorbed on the surface of catalysts. Here we develop a general method for in situ monitoring of heterogeneous catalytic processes through shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS) satellite nanocomposites (Au-core silica-shell nanocatalyst-satellite structures), which are stable and have extremely high surface Raman sensitivity. By combining operando SHINERS with density functional theory calculations, we identify the working mechanisms for CO oxidation over PtFe and Pd nanocatalysts, which are typical low- and high-temperature catalysts, respectively. Active species, such as surface oxides, superoxide/peroxide species and Pd-C/Pt-C bonds are directly observed during the reactions. We demonstrate that in situ SHINERS can provide a deep understanding of the fundamental concepts of catalysis.