The investigation of the synthesis of pure-phase ZSM-22 zeolites and their catalytic performance in the n-hexane cracking reaction is of critical significance for industrial production. To enhance ...the crystallinity of ZSM-22, ethylene glycol was integrated into the synthesis gel, effectively suppressing the formation of quartz and ZSM-5 impurities. Due to the structure-directing effect of ethylene glycol, the ZSM-22 prepared demonstrates much more mesopores compared to the counterparts without ethylene glycol addition. Furthermore, the acid strength and density of the zeolite increased significantly. These pure-phase ZSM-22 samples exhibited enhanced performance in terms of both conversion efficiency and ethylene selectivity during n-hexane cracking, which is associated with the increased abundance of acid sites and a higher ratio of strong to weak acids. These findings highlight the beneficial effects of ethylene glycol modification on the regulation of crystal growth and the enhancement of catalytic performance in ZSM-22 catalysts.
The freezing characteristics of supercooled water in a gas diffusion layer (GDL), which are the bases for the cold start-up of proton exchange membrane fuel cells (PEMFCs), were investigated. An ...experimental apparatus for noncontact temperature measurement and observation systems was developed. GDL and GDL with a microporous layer (MPL) were prepared, and freezing experiments using a water-containing GDL under various cooling rates were performed with variations in polytetrafluoroethylene (PTFE) content and water saturation. Furthermore, based on the experimental results, the freezing initiation probability was theoretically investigated to elucidate the freezing characteristics. Results showed that, with increasing supercooling of water in GDL, the freezing probability of water increased abruptly. The effect of saturation showed a different trend depending on PTFE addition. For the GDL without PTFE, the freezing initiations occurred at approximately 6 °C of supercooling degree, and the probability approached 1.0 at approximately 9.5–11.5 °C, with saturation dependency. In contrast, for both GDL and GDL + MPL containing PTFE, the initiation temperature characteristics were relatively similar, which were approximately 8–12 °C, regardless of the saturation and PTFE content. In these cases, the ice-nucleating activity of water in the GDL was possibly stronger than that in the MPL.
•Non-contact measurement/observation are developed for supercooled water freezing.•Effect of saturation in GDL shows different trend depending on PTFE content.•Freezing occurs at supercooling of 6–9.5–11.5 K with saturation for without PTFE.•8–12 K of supercooling regardless of saturation & PTFE for GDL & GDL + MPL with PTFE.•Freezing probability is analyzed for freezing characteristics of GDL & GDL + MPL.
Mercury (Hg) in soils has increased by a factor of 3 to 10 in recent times mainly due to combustion of fossil fuels combined with long-range atmospheric transport processes. Other sources as ...chlor-alkali plants, gold mining and cement production can also be significant, at least locally. This paper summarizes the natural and anthropogenic sources that have contributed to the increase of Hg concentration in soil and reviews major remediation techniques and their applications to control soil Hg contamination. The focus is on soil washing, stabilisation/solidification, thermal treatment and biological techniques; but also the factors that influence Hg mobilisation in soil and therefore are crucial for evaluating and optimizing remediation techniques are discussed. Further research on bioremediation is encouraged and future study should focus on the implementation of different remediation techniques under field conditions.
•Sources of Hg contamination in soil are reviewed.•Factors affecting Hg mobility in soil are focused.•Predominant remediation techniques for Hg contaminated soil are reviewed.•Factors that influence treatment efficiency of Hg polluted soil are discussed.•Means of improving soil washing and S/S techniques are also emphasized.
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•Facile synthesis of stearic acid-loaded hydrophobic activated carbon is proposed.•20 % ST-AC: surface specific area is 1655 m2/g and water contact angel is 132°.•Doping stearic acid ...increases the Π-Π force between toluene and AC.•Adsorption capacity of 20 % ST-AC is 545 mg/g at 0 %RH and 490 mg/g at 80 % RH.•Adsorption capacity of regenerated 20% ST-AC remains more than 94% after 5 cycles.
The diminished adsorption efficiency of porous carbon for volatile organic compounds (VOCs) in high-humidity conditions poses a critical challenge that limits its widespread application. This study presents a facile method for enhancing the adsorption capacity of coffee grounds activated carbon in high-humidity environments through stearic acid modification. The incorporation of 20 % stearic acid (20 % ST-AC) significantly amplifies the saturated adsorption capacity and penetration duration of porous carbon for toluene under high-humidity conditions. Specifically, the toluene adsorption capacity improves from 230 mg/g to 498 mg/g in an 80 % relative humidity condition. However, increasing the stearic acid doping ratio beyond 20 % has a limited impact on moisture resistance while leading to micropore blockage, resulting in a significant reduction in toluene adsorption capacity. Additionally, 20 % ST-AC demonstrates excellent adsorption recycling performance over five cycles, maintaining 97 % of its original adsorption capacity. This study provides a novel perspective on the preparation of hydrophobic activated carbon, which helps to address the challenge of VOC adsorption in high-humidity flue gas environments.
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•V doped CuO/γ-Al2O3 is promising for toluene oxidation in the presence of SO2.•The relationship between performance and physicochemical properties is discussed.•Reaction pathway of ...toluene over sulfates covered Cu-V/γ-Al2O3 is proposed.
To efficiently oxidize toluene in SO2-containing flue gas, different non-noble metals (V, Ce and Mo) were successfully introduced into Cu‐based catalysts (Cu-M/γ-Al2O3). Results show that the temperature corresponding to 90% CO2 generation (T90,C) of CuO/γ-Al2O3 in toluene oxidation is decreased by ca. 11–46 ℃ after introducing an additional metal oxide, which is attributed to a bimetallic synergy. Among the three different metals, V is found to have the most obvious promoting effect, which is mainly connected with the big average pore size, good reducibility and high content of surface adsorbed oxygen (OS). Furthermore, the reaction pathways of the toluene oxidation on both the fresh Cu-V/γ-Al2O3 and the SO2-treated Cu-V/γ-Al2O3 are investigated by in-situ DRIFTS. For SO2-treated Cu-V/γ-Al2O3, we found an additional pathway: toluene–benzene–benzoquinone–maleic anhydride–CO2 and H2O. This new pathway can help to explain the decrease of the CO2 generation rate in the presence of SO2.
Here, we report a case of blood culture-confirmed typhoid fever, rhabdomyolysis, and multiple organ damage that arrived in our country from overseas. A 23-year-old male patient presented at our ...hospital with fever and muscle pain; the condition progressed rapidly. Six days after the onset of symptoms, the patient developed rhabdomyolysis and liver/kidney damage; levels of creatine kinase (CK; maximum peak: 729,869 U/L) and myoglobin (> 3,000 ng/mL) were extremely high, although the extent of renal damage was relatively mild. Blood culture showed Salmonella typhi. The patient received a combination of meropenem and levofloxacin anti-infective therapy, as well as fluid and nutritional metabolic support. He gradually recovered and was discharged after two negative blood cultures. This case highlights the fact that typhoid-induced rhabdomyolysis is a serious, life-threatening disease and that the levels of CK and myoglobin are useful indicators for evaluating typhoid-induced rhabdomyolysis. Clinicians should remain vigilant regarding travel-related illnesses associated with enteric fever.
High-grade gliomas (HGGs) of childhood represent approximately 7% of pediatric brain tumors. They are highly invasive tumors and respond poorly to conventional treatments in contrast to pilocytic ...astrocytomas, which usually are well demarcated and frequently can be cured by surgery. The molecular events for this clinical relevant finding are only partially understood. In the current study, to identify aberrantly methylated genes that may be involved in the tumorigenesis of pediatric HGGs, we performed a microarray-based differential methylation hybridization approach and found frequent hypermethylation of the LHX9 (human Lim-homebox 9) gene encoding a transcription factor involved in brain development. Bisulfite genomic sequencing and combined bisulfite restriction analysis showed that HGGs were frequently methylated at two CpG-rich LHX9 regions in comparison to benign, nondiffuse pilocytic astrocytomas and normal brain tissues. The LHX9 hypermethylation was associated with reduced messenger RNA expression in pediatric HGG samples and corresponding cell lines. This epigenetic modification was reversible by pharmacological inhibition (5-aza-2′-deoxycytidine), and reexpression of LHX9 transcript was induced in pediatric glioma cell lines. Exogenous expression of LHX9 in glioma cell lines did not directly affect cell proliferation and apoptosis but specifically inhibited glioma cell migration and invasion in vitro, suggesting a possible implication of LHX9 in the migratory phenotype of HGGs. Our results demonstrate that the LHX9 gene is frequently silenced in pediatric malignant astrocytomas by hypermethylation and that this epigenetic alteration is involved in glioma cell migration and invasiveness.
Co-firing ammonia in coal-fired utility boilers is a promising de-carbon technical route for power stations, yet currently, there is still no information on how co-firing ammonia would affect the ...release and conversion of volatiles. Here, coal pellets were burned with/without ammonia co-firing on a flat-flame burner facility in both fuel-lean and -rich conditions. Detailed information on time-resolved evolution of volatile flame, size evolution of soot particles in flame, and changes in their physiochemical structures was obtained. It was observed that co-firing ammonia promoted devolatilization of coal and release of volatiles, leading to an earlier ignition moment in both fuel-lean and -rich conditions. In the flame, massive soot particles were formed from volatiles, and co-firing ammonia affected the conversion of volatiles into soot and changed the flame radiation properties. Interestingly, both the number density of all soot and size of primary soot particles increased after co-firing ammonia in fuel-lean conditions (by 2.5 times and ∼10 nm, respectively), while they decreased in fuel-rich conditions. In fuel-lean conditions, co-firing ammonia promoted inception and surface growth of soot due to competitive consumption of O2 and increased flame temperature, while in fuel-rich conditions, these effects were offset by partial consumption of soot precursors by forming nitrogen-containing species. Furthermore, when ammonia was co-fired, fringe length, tortuosity, and especially inter-fringe spacing of soot increased slightly, indicating that particles formed in co-firing flames might show higher oxidation reactivity than those formed without ammonia co-firing.
•Coal had interactions with NH3 when co-firing.•Both volatile and char could increase the NOx emission when co-firing with NH3.•NH3-N converted to NOx caused a higher NOx emission in the co-firing ...cases.•Volatile and char increased reaction rate of NH3 oxidation and formed more NO.
Co-firing ammonia with pulverized coal presents a promising strategy for reducing CO2 emissions in coal-fired power plants. However, there are concerns regarding the NOx formation behavior of ammonia. In this study, the effects of coal on ammonia-N (NH3-N) conversion behavior were explored by combustion experiments using a drop tube furnace, and the interactions between ammonia and coal were further analyzed using computational fluid dynamics (CFD) simulations. The results showed that co-firing ammonia and coal/char could increase NOx formation, and the conversion ratio of fuel-N into NOx was also increased. The comparison of ammonia-coal and ammonia-char co-firing demonstrated that coal had a stronger effect on NH3-N conversion than char, further inferring that both char and volatile significantly increased the conversion of NH3-N to NOx. The simulation results suggested that 23.82% of the total NO emissions originated from coal, and 76.18% from ammonia in ammonia-coal co-firing, indicating that NH3-N was the primary source of the increased NOx, and the interactions between ammonia and coal/char increased the conversion of NH3-N to NOx. The interaction between coal (both volatile and char) and ammonia contributed to an overall increase in the ammonia average reaction rate, with the ammonia's average oxidation reaction rate displaying a much more pronounced increase. This further led to the formation of NOx and the conversion of NH3-N to NOx in ammonia-coal co-firing conditions.
Inhibition of integrins αvβ3/αvβ5 by the cyclic function-blocking peptide, RGDfV (Arg-Gly-Asp-Phe-Val) can induce apoptosis in both normal cells and tumor cells. We show that RGDfV induced apoptosis ...in ECV-304 carcinoma cells, increased activity and mRNA expression of acid sphingomyelinase (ASM), and increased ceramides C(16), C(18:0), C(24:0) and C(24:1) while decreasing the corresponding sphingomyelins. siRNA to ASM decreased RGDfV-induced apoptosis as measured by TUNEL, PARP cleavage, mitochondrial depolarization, and caspase-3 and caspase-8 activities, as well as by annexinV in a 3D collagen model. These findings indicate a causal role for ASM in RGDfV-induced apoptosis in ECV-304. We have shown that c-Abl, a non-receptor tyrosine kinase, also mediates RGDfV-induced apoptosis. However, c-Abl, has not been previously linked to ASM in any system. Here we show that STI-571 (imatinib, inhibitor of c-Abl) inhibited RGDfV-induced ASM activity. Furthermore, STI-571 and c-Abl-siRNA both inhibited RGDfV-induced increase in ASM mRNA, but ASM-siRNA did not affect c-Abl phosphorylation or expression, supporting that c-Abl regulates the RGDfV-induced increase in ASM expression. These studies implicate ASM as a mediator of apoptosis induced by inhibition of integrins αvβ3/αvβ5, and for the first time place c-Abl as an upstream regulator of ASM expression and activity.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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