Solvent-free crystallization of ZSM-5 zeolite on SiC foam as a monolith catalyst for biofuel upgrading

Conventional synthesis of monolith-supported zeolite catalysts is based on a hydrothermal strategy.Here,we report a solvent-free crystallization process to coat ZSM-5 zeolite crystals on a monolithic SiC foam with a honeycomb structure(ZSM-5/SiC).Characterizations of the ZSM-5/SiC by scanning electron microscopy,N2 sorption,and X-ray diffraction indicate that the zeolite sheath has been ideally coated on the surface of the SiC foam with high purity and crystallinity.Fixing Pd nanoparticles within the ZSM-5 zeolite crystals delivers a bifunctional Pd@ZSM-5/SiC catalyst,which exhibits high activity and selectivity toward diesel range paraffins in the hydrodeoxygenation of methyl oleate,a model molecule for biofuel.In comparison to the powder Pd@ZSM-5,the Pd@ZSM-5/SiC monolith catalyst shows more efficiency,which is attributed to the fast mass transfer and high heat conductivity on the honeycomb SiC structure.The durability test indicates that the Pd@ZSM-5/SiC catalyst is stable under the reaction and high-temperature regeneration conditions.

Insights into the Organotemplate-Free Synthesis of Zeolite Catalysts

As the most important nanoporous material, zeolites, which have intricate micropores, are essential heterogeneous catalysts in industrial processes. Zeolites are generally synthesized with organic templates under hydrothermal conditions; however, this method is environmentally unfriendly and costly due to the formation of harmful gases and polluted water. This article briefly summarizes the role of organic templates and describes designed routes for the organotemplate-free synthesis of zeolites, aided by zeolite seeds and zeolite seeds solution. Furthermore, this review explicates that the micmpore volume decreases with an increase of the Si/Al ratios in the organotemplate-free synthesis of zeolite products, where Na^＋ exists as an alkali cation. This feature is very important in directing the synthesis of zeolite catalysts with controllable Si/AI ratios under organotemplate-free conditions, and is thus important for the efficient design of zeolites.

Different dosages of methylprednisolone therapy for acute necrotizing encephalopathy of childhood:a 6-year multicenter retrospective study

To the Editor:Acute necrotizing encephalopathy(ANE)is a rare but often devastating neurologic disorder in children.[1]Hereditary susceptibility and cytokine storm play important roles in ANE pathogenesis,[2,3]but the specific molecular biological mechanism is unclear.

Crystal growth,structure and laser performance of a new Yb^(3+):KBaY(MoO_(4))_(3) crystal

A Yb^(3+):KBaY(MoO_(4))_(3)(Yb^(3+):KBYM)crystal with dimensions of 51 mm×27 mm × 10 mm was successfully grown by the TSSG method.The characteristics of the crystal structure and probability of good optical properties were analyzed.The absorption and emission spectra of Yb^(3+):KBYM crystal exhibit broadened bands,with the maximum absorption cross-sections of 1.17 × 10^(-20),1.44×10^(-20) and 1.37 × 10^(-20) cm^(2) at976 nm for X-,Y-and Z-polarizations,respectively.The corresponding absorption FWHMs are as wide as 77,46 and 55 nm.The well-known re-absorption effect of Yb^(3+) in the crystal is discussed.Two methods,the Fiichtbauer-Ladenburg method(FL)and reciprocity method(RM)were adopted to compute the emission cross-sections and results show a certain discrepancy but the errors are allowable.The laser potentiality of the Yb^(3+):KBYM crystal was also evaluated by calculations of minimum inversion fractionβmin,saturation pump intensity Isat,the minimum pump intensity Imin and gain cross-sections spectra.Laser experiment was carried out and Watt-level continuous wave laser has been realized.Results indicate that the Yb^(3+):KBYM crystal with a disordered structure may be a potential laser media that can be used to generate tunable and ultrashort pulse laser emissions with high quality beam.

Plasma exchange therapy for acute necrotizing encephalopathy of childhood

Importance Acute necrotizing encephalopathy(ANE)is a rare disease with high mortality.Plasma exchange(PLEX)has recently been reported to treat ANE of childhood(ANEC),but its efficacy is uncertain.Objective This study aimed to investigate the effectiveness of PLEX on ANEC.Methods A retrospective study was conducted in four pediatric intensive care units from December 2014 to December 2020.All patients who were diagnosed with ANEC were included;however,these patients were excluded if their length of stay was less than 24 h.Participants were classified into PLEX and non-PLEX groups.Results Twenty-nine patients with ANEC were identified,10 in the PLEX group and 19 in the non-PLEX group.In the PLEX group,C-reactive protein,procalcitonin,alanine aminotransferase,and aspartate aminotransaminase levels were significantly lower after 3 days of treatment than before treatment(13.1 vs.8.0,P=0.043;9.8 vs.1.5,P=0.028;133.4 vs.31.9,P=0.028;282.4 vs.50.5,P=0.046,respectively).Nine patients(31.0%,9/29)died at discharge,and a significantly difference was found between the PLEX group and non-PLEX group[0 vs.47.4%(9/19),P=0.011].The median follow-up period was 27 months,and three patients were lost to follow-up.Thirteen patients(50.0%,13/26)died at the last follow-up,comprising three(33.3%,3/9)in the PLEX group and ten(58.8%,10/17)in the non-PLEX group,but there was no significant difference between the two groups(P=0.411).Three patients(10.3%,3/29)fully recovered.Interpretation PLEX may reduce serum C-reactive protein and procalcitonin levels and improve liver function in the short term.PLEX may improve the prognosis of ANEC,and further studies are needed.