Mice Deficient in Cyp4a14 Have An Increased Number of Goblet Cells and Attenuated Dextran Sulfate Sodium-Induced Colitis

Background/Aims: Cyp4a14 is a member of cytochrome P450 (Cyp450) enzyme superfamily that possesses NADPH monooxygenase activity, which catalyzes omega-hydroxylation of medium-chain fatty acids and arachidonic acid. Study suggests that down-regulation of Cyp4a14 has an anti-inflammatory response in intestine. The present study was to test the function of Cyp4a14 in dextran sulfate sodium (DSS)-induced colitis. Methods: Female Cyp4a14-knockout (KO) and wild-type (WT) mice were treated with DSS for 6 days to induce colitis. The colon of mice was histologically observed by hematoxylin and eosin (H&E) and periodic acid Schiff (PAS) staining. The serum malondialdehyde (MDA), an endogenous indicator of oxidative stress, was chemically measured. Proinflammatory and NADPH oxidase genes were examined by quantitative polymerase chain reaction (qPCR). Results: Cyp4a14-KO mice had a significantly higher number of goblet cells in the colon and were more resistant to DSS-induced colitis compared with the WT mice. The DSS-treated KO mice had lower levels of MDA. Consistent with the milder inflammatory pathological changes, DSS-treated KO mice had lower levels of IL-1β, IL-6 and TNF-α mRNA in the liver and the colon. Moreover, the colon of DSS-treated Cyp4a14-KO and WT mice had higher mRNA levels of two members of NADPH oxidases, Nox2 and Nox4, suggesting that both Nox2 and Nox4 are inflammatory markers. By contrast, DSS-treated WT and KO mice had drastically decreased epithelium-localized Nox1 and dual oxidase (Duox) 2 mRNA levels, coinciding with the erosion of the mucosa induced by DSS. Conclusion: These results suggests a hypothesis that the increased goblet cell in the colon of Cyp4a14-KO mice provides protection from mucosal injury and Cyp4a14-increased oxidative stress exacerbates DSS-induced colitis. Therefore, Cyp4a14 may represent a potential target for treating colitis

Error Compensation on Probe Parameters of Articulated Arm CMM

The error compensations on probe parameters were proposed to improve the measurement accuracy of an articulated arm coordinate measuring machines (AACMM). An AACMM’s probe parameters were analyzed and a measurement model including probe parameters solely was built. A simple cone socket components were used as a calibration tool and the LM algorithm was edited to solve the probe parameters. The results show that the average measurement error dealt with the probe parameters recalibration is 0.044mm, and its standard deviation is 0.050mm. They have increased by about 31% and 33% than those without recalibration

Error Compensation on Probe Parameters of Articulated Arm CMM

The error compensations on probe parameters were proposed to improve the measurement accuracy of an articulated arm coordinate measuring machines (AACMM). An AACMM’s probe parameters were analyzed and a measurement model including probe parameters solely was built. A simple cone socket components were used as a calibration tool and the LM algorithm was edited to solve the probe parameters. The results show that the average measurement error dealt with the probe parameters recalibration is 0.044mm, and its standard deviation is 0.050mm. They have increased by about 31% and 33% than those without recalibration

Plasma-catalytic pyrolysis of polypropylene for hydrogen and carbon nanotubes: Understanding the influence of plasma on volatiles

Plasma-catalytic pyrolysis was developed for upgrading polypropylene (PP) pyrolysis volatiles to co-produce carbon nanotubes (CNTs) and hydrogen. To uncover the role of plasma on the plastic catalytic pyrolysis process, the pyrolysis of polypropylene (PP) over Fe/γ-Al2O3 was carried out in a two-stage pyrolysis system with a coaxial dielectric barrier discharge (DBD) plasma reactor. The results showed that the plastic pyrolysis volatiles were further cleaved and activated with plasma, resulting in more active carbon species for the growth of CNTs. Compared to conventional catalytic pyrolysis, plasma addition shifted the initial formation temperature of CNTs to a lower ambient temperature by ∼100 °C, and significantly promoted the conversion of liquid and gaseous products to CNTs and hydrogen, with higher carbon and hydrogen yields of ∼322 mg/gplastic and 30 mmol/gplastic, respectively. In addition, the degree of graphitization of the CNTs in the presence of the plasma was significantly enhanced with less defectivity. The influence of catalytic temperature variation caused by plasma on CNTs growth was also discussed from the perspective of volatile evolution. This work highlights the potential of plasma-catalytic pyrolysis for the production of hydrogen and high-value carbon materials from plastic waste

Selective conversion of syngas to light olefins

Although considerable progress has been made in direct synthesis gas (syngas) conversion to light olefins (C-2(=)-C-4(=)) via Fischer-Tropsch synthesis (FTS), the wide product distribution remains a challenge, with a theoretical limit of only 58% for C-2-C-4 hydrocarbons. We present a process that reaches C-2(=)-C-4(=) selectivity as high as 80% and C-2-C-4 94% at carbon monoxide (CO) conversion of 17%. This is enabled by a bifunctional catalyst affording two types of active sites with complementary properties. The partially reduced oxide surface (ZnCrOx) activates CO and H-2, and C-C coupling is subsequently manipulated within the confined acidic pores of zeolites. No obvious deactivation is observed within 110 hours. Furthermore, this composite catalyst and the process may allow use of coal-and biomass-derived syngas with a low H-2/CO ratio