http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Alarba Albertine Sam-Tunsa,Kassem Nourhan Nabil,Nana Achile,Taypondou Japhet Darman,Sakue Eric Ngankam,Moctar Iyamni Bintou,Nchare Mominou,Kumar Sanjay 한국자원공학회 2023 Geosystem engineering Vol.26 No.6
This paper examines the potential use of pegmatite and marble as additives in amalgamation with Meiganga kaolin to produce stoneware products capable to resist high temperatures as well as enhancement the mechanical characteristics. Two series of ceramic products were formulated by partly replacing kaolin with 0, 3, 5 and 7 wt% of both pegmatite and marble wastes. The specimens were sintered at 1000°C, 1050°C and 1100°C. Fired ceramic samples were characterized by X-ray diffraction, Fourier transform infrared spectroscopy and the microstructure of the products was determined using an environmental scanning electron microscope and energy-dispersive X-ray spectroscopy. Also, the physico-mechanical properties were evaluated. Results divulged that, the addition of pegmatite or marble to kaolin enhances the strength of the ceramic body and act as a fluxing agent by promoting vitrification and glassy phase in clay after firing. The highest flexural strength results were observed with 7 wt% of pegmatite added at 1100 °C, with an increase ~ 35% compared to the control sample. High silica and alumina contents in pegmatite fill in voids, providing densification matrices. The incorporation of pegmatite allows to obtain a ceramic with better mechanical properties and energy saving as compared by the conventional ceramic.
Blunted hypoxic pulmonary vasoconstriction in experimental neonatal chronic lung disease.
Rey-Parra, Gloria Juliana,Archer, Stephen L,Bland, Richard D,Albertine, Kurt H,Carlton, David P,Cho, Soo-Chul,Kirby, Beth,Haromy, Al,Eaton, Farah,Wu, Xichen,Thé,baud, Bernard American Lung Association 2008 American journal of respiratory and critical care Vol.178 No.4
<P>RATIONALE: Neonatal chronic lung disease (CLD), caused by prolonged mechanical ventilation (MV) with O(2)-rich gas, is the most common cause of long-term hospitalization and recurrent respiratory illness in extremely premature infants. Recurrent episodes of hypoxemia and associated ventilator adjustments often lead to worsening CLD. The mechanism that causes these hypoxemic episodes is unknown. Hypoxic pulmonary vasoconstriction (HPV), which is partially controlled by O(2)-sensitive voltage-gated potassium (K(v)) channels, is an important adaptive response to local hypoxia that helps to match perfusion and ventilation in the lung. OBJECTIVES: To test the hypothesis that chronic lung injury (CLI) impairs HPV. METHODS: We studied preterm lambs that had MV with O(2)-rich gas for 3 weeks and newborn rats that breathed 95%-O(2) for 2 weeks, both of which resulted in airspace enlargement and pulmonary vascular changes consistent with CLD. MEASUREMENTS AND MAIN RESULTS: HPV was attenuated in preterm lambs with CLI after 2 weeks of MV and in newborn rats with CLI after 2 weeks of hyperoxia. HPV and constriction to the K(v)1.x-specific inhibitor, correolide, were preferentially blunted in excised distal pulmonary arteries (dPAs) from hyperoxic rats, whose dPAs exhibited decreased K(v)1.5 and K(v)2.1 mRNA and K(+) current. Intrapulmonary gene transfer of K(v)1.5, encoding the ion channel that is thought to trigger HPV, increased O(2)-sensitive K(+) current in cultured smooth muscle cells from rat dPAs, and restored HPV in hyperoxic rats. CONCLUSIONS: Reduced expression/activity of O(2)-sensitive K(v) channels in dPAs contributes to blunted HPV observed in neonatal CLD.</P>