3 resultados para time of nitrogen application

em WestminsterResearch - UK


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This article offers a close critical reading of Blanchot's essay on Surrealism, 'Tomorrow at Stake', raising a series of questions concerning the time of 'Surrealist experience' and its relation to those temporal structures inscribed within the concepts of modernity, the avant-garde, and (art) history itself. It is argued, through a posited connection to Romantic conceptions of the fragment, that those 'reflexes of the future' which for Surrealism determine the value of the present, may be understood, philosophically, in relation to diverse conceptions of the 'openness' of the question, in turn suggesting a more complex understanding of Surrealism's 'avant-garde' character.

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Plantaginis Semen is commonly used in traditional medicine to treat edema, hypertension, and diabetes. The commercially available Plantaginis Semen in China mainly comes from three species. To clarify the chemical composition and distinct different species of Plantaginis Semen, we established a metabolite profiling method based on ultra high performance liquid chromatography with electrospray ionization quadrupole time-of-flight tandem mass spectrometry coupled with elevated energy technique. A total of 108 compounds, including phenylethanoid glycosides, flavonoids, guanidine derivatives, terpenoids, organic acids, and fatty acids, were identified from Plantago asiatica L., P. depressa Willd., and P. major L. Results showed significant differences in chemical components among the three species, particularly flavonoids. This study is the first to provide a comprehensive chemical profile of Plantaginis Semen, which could be involved into the quality control, medication guide, and developing new drug of Plantago seeds.

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Sweroside, a major active iridoid in Swertia pseudochinensis Hara, is recognized as an effective agent in the treatment of liver injury. Based on previous reports, the relatively short half-life (64 min) and poor bioavailability (approximately 0.31%) in rats suggested that not only sweroside itself but also its metabolites could be responsible for the observed hepato-protective effect. However, few studies have been carried out on the metabolism of sweroside. Therefore, the present study aimed at identifying the metabolites of sweroside in rat urine after a single oral dose (100 mg/kg). With ultra-high-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UHPLC/Q-TOF-MS), the metabolic profile revealed 11 metabolites in rat urine, including phase I, phase II and aglycone-related products. The chemical structures of metabolites were proposed based on accurate mass measurements of protonated or deprotonated molecules and their fragmentation patterns. Our findings showed that the aglycone of sweroside (M05) and its glucuronide conjugate (M06) were principal circulating metabolites in rats. While several other metabolic transformations, occurring via reduction, N-heterocyclization and N-acetylation after deglycosylation, were also observed. Two metabolites (M05 and M06) were isolated from the rat urine for structural elucidation and identifcation of reaction sites. Both M05 and M06 were characterized by 1H, 13C and two-dimensional nuclear magnetic resonance (NMR) spectroscopy. UHPLC/Q-TOF-MS analysis has provided an important analytical platform to gather metabolic profile of sweroside.