Effects of the ZrO2 Crystalline Phase and Morphology on the Thermocatalytic Decomposition of Dimethyl Methylphosphonate.

Thermocatalytic decomposition is an efficient purification technology that is potentially applicable to degrading chemical warfare agents and industrial toxic gases. In particular, ZrO2 has attracted attention as a catalyst for the thermocatalytic decomposition of dimethyl methylphosphonate (DMMP), which is a simulant of the nerve gas sarin. However, the influence of the crystal phase and morphology on the catalytic performance of ZrO2 requires further exploration. In this study, monoclinic- and tetragonal-phase ZrO2 (m- and t-ZrO2, respectively) with nanoparticle, flower-like shape and hollow microsphere morphologies were prepared via hydrothermal and solvothermal methods, and their thermocatalytic decomposition of DMMP was systematically investigated. For a given morphology, m-ZrO2 performed better than t-ZrO2. For a given crystalline phase, the morphology of hollow microspheres resulted in the longest protection time. The exhaust gases generated by the thermocatalytic decomposition of DMMP mainly comprised H2, CO2, H2O and CH3OH, and the by-products were phosphorus oxide species. Thus, the deactivation of ZrO2 was attributed to the deposition of these phosphorous oxide species on the catalyst surface. These results are expected to help guide the development of catalysts for the safe disposal of chemical warfare agents.

The Enhancement of CO Oxidation Performance and Stability in SO2 and H2S Environment on Pd-Au/FeOX/Al2O3 Catalysts.

Carbon monoxide (CO) is a colourless, odourless, and toxic gas. Long-term exposure to high concentrations of CO causes poisoning and even death; therefore, CO removal is particularly important. Current research has focused on the efficient and rapid removal of CO via low-temperature (ambient) catalytic oxidation. Gold nanoparticles are widely used catalysts for the high-efficiency removal of high concentrations of CO at ambient temperature. However, easy poisoning and inactivation due to the presence of SO2 and H2S affect its activity and practical application. In this study, a bimetallic catalyst, Pd-Au/FeOx/Al2O3, with a Au:Pd ratio of 2:1 (wt%) was formed by adding Pd nanoparticles to a highly active Au/FeOx/Al2O3 catalyst. Its analysis and characterisation proved that it has improved catalytic activity for CO oxidation and excellent stability. A total conversion of 2500 ppm of CO at -30 °C was achieved. Furthermore, at ambient temperature and a volume space velocity of 13,000 h-1, 20,000 ppm CO was fully converted and maintained for 132 min. Density functional theory (DFT) calculations and in situ FTIR analysis revealed that Pd-Au/FeOx/Al2O3 exhibited stronger resistance to SO2 and H2S adsorption than the Au/FeOx/Al2O3 catalyst. This study provides a reference for the practical application of a CO catalyst with high performance and high environmental stability.

SpyGlass-guided laser lithotripsy versus laparoscopic common bile duct exploration for large common bile duct stones: a non-inferiority trial.

BACKGROUND: Laparoscopic common bile duct exploration (LCBDE) is the first choice of treatment for large common bile duct (CBD) stones. Recently, single-operator cholangioscopy (SpyGlass system) has been introduced widely in referral and large medical centers. Several studies have reported favorable results for treatment of large CBD stones guided by SpyGlass. We evaluated the clinical efficacy and safety of SpyGlass-guided laser lithotripsy LCBDE for treatment of large CBD stones. METHODS: From August 2015 to August 2018, 157 patients with large bile duct stones who met the inclusion criteria were randomly divided into two groups: SpyGlass-guided laser lithotripsy (Group A) and LCBDE (Group B). The efficacy and complications were compared between the groups. RESULTS: Although the first-session stone removal rate in Group A was significantly lower than that in Group B, Group A was not inferior to Group B in terms of total stone removal rate. Compared with Group B, Group A had shorter hospital stay and enhanced recovery. The short-term complication rates were also similar between the two groups. CONCLUSIONS: The clinical efficacy of SpyGlass-guided laser lithotripsy for the treatment of large CBD stones is not inferior to that of LCBDE, and it is less invasive. SpyGlass-guided laser lithotripsy is an important option for treatment of large CBD stones.

Comparison of Microstructure and Properties of In-Situ TiN- and WC-Reinforced NiCrBSi Composite Coatings Prepared by Plasma Spraying.

In this study, NiCrBSi-30 wt.% TiN composite (NTC) coating was produced on carbon steel via plasma spraying, with NiCrBSi-30 wt.% WC composite (NWC) coating as the comparison object. The microstructure and phase constituents of the composite coatings were characterized using scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS) techniques, transmission electron microscopy (TEM) and x-ray diffraction (XRD). Atomic force microscopy (AFM) was used to measure electronic work functions. The microhardness and wear performance of coatings were also investigated. The average microhardness of the NTC and NWC coatings was 1000 HV and 850 HV, respectively. In addition, the NTC coating had a wear volume loss of 0.8118 mm³, less than 1.4772 mm³, the volume loss of the NWC coating. This was due to the presence of TiN in the form of nanograins in the composite coating and tighter binding to the matrix.

Pancreatic Stent or Rectal Indomethacin-Which Better Prevents Post-ERCP Pancreatitis?: A Propensity Score Matching Analysis.

We investigated and compared 2 clinical strategies to prevent postendoscopic retrograde cholangiopancreatography (ERCP) pancreatitis (PEP).We retrospectively reviewed data from patients who underwent ERCP between 2008 and 2014. Of 623 patients at high risk for PEP, 145 were treated with prophylactic pancreatic stent placement (PSP) only, and 478 were treated with rectal indomethacin (RI) only, for PEP prevention. Patients were matched by one-to-one propensity score matching (PSM) by risk factors, with overall PEP incidence as primary outcome, and moderate or severe PEP and complication rates as secondary outcomes.Of 623 patients with high-risk factors, 145 pairs were generated after PSM. Thirty-two patients developed pancreatitis-10 (6.9 %) in the PSP group and 22 (15.2 %) in the RI group (P = 0.025). Moderate-to-severe pancreatitis developed in 5 patients (2.8%) in the PSP group and 14 patients (9.7 %) in the RI group (P = 0.047).Although indomethacin represents an easy, inexpensive treatment, prophylactic PSP is still the better prevention strategy for PEP.

Dilation-assisted stone extraction: an alternative method for removal of common bile duct stones.

BACKGROUND: Dilation-assisted stone extraction, also termed small endoscopic sphincterotomy (EST) plus endoscopic papillary balloon dilatation, is more efficient than EST alone for removal of large common bile duct (CBD) stones. However, whether this technique can be used for all stones is unclear. AIM: This study was designed to evaluate the efficacy and complications of dilation-assisted stone extraction for CBD stones. METHODS: A total of 462 patients with CBD stones were randomized to undergo either dilation-assisted stone extraction (group A) or EST (group B). The efficacy and complications of the two techniques were compared. RESULTS: Groups A and B showed similar outcomes in terms of stone removal. The short-term and 1-year complication rates were also similar between the two groups. However, the first-session stone removal rate in group A was significantly higher than that in group B. Mechanical lithotripsy was required significantly more often in group B than in group A. The total procedure time and total fluoroscopy time in group A were significantly shorter than those in group B. CONCLUSIONS: Dilation-assisted stone extraction and EST are safe and effective techniques for the treatment of CBD stones. Dilation-assisted stone extraction has high efficiency. This technique is an alternative method for removal of CBD stones.