Structure Elucidation and Toxicity Analysis of the Degradation Products of Deoxynivalenol by Gaseous Ozone

Fusarium Head Blight (FHB) or scab is a fungal disease of cereal grains. Wheat scab affects the yield and quality of wheat and produces mycotoxins such as deoxynivalenol (DON), which can seriously threaten human and animal health. In this study, gaseous ozone was used to degrade DON in wheat scab and the degradation products of ozonolysis were analyzed by ultra-performance liquid chromatography quadrupole-orbitrap mass spectrometry (UHPLC Q-Orbitrap). Toxicology analyses of the degradation products were also studied using structure-activity relationships. Ozone (8 mg L−1 concentration) was applied to 2 μg mL−1 of DON in ultrapure water, resulted in 95.68% degradation within 15 s. Ten ozonized products of DON in ultrapure water were analyzed and six main products (C15H18O7, C15H18O9, C15H22O9, C15H20O10, C15H18O8, and C15H20O9) were analyzed at varying concentrations of ozone and DON. Structural formulae were assigned to fragmentation products generated by MS2 and Mass Frontier® software. According to structure-activity relationship studies, the toxicities of the ozonized products were significantly decreased due to de-epoxidation and the attack of ozone at the C9-10 double bond in DON. Based on the results of the study above, we can find that gaseous ozone is an efficient and safe technology to degrade DON, and these results may provide a theoretical basis for the practical research of detoxifying DON in scabby wheat and other grains.

Toward identifying the critical mass in spatial two-sided markets

Unlike their nonspatial counterparts, spatial multi-sided platforms are matchmaking platforms with an additional layer of complexity: their customers expect to meet in space, not only virtually. This additional challenge will be studied in this paper in the context of a two-sided ride-sharing platform, which serves drivers and passengers. As with any two-sided platform, there is an interdependence between both groups of customers: More drivers are more attractive for passengers, and vice versa. This interdependence creates the old chicken-and-egg problem, only that here drivers and passengers need to be matched not for a virtual transaction, but by their ability to meet physically and travel jointly. We argue, and illustrate by simulations, that in spatial multi-sided markets there is not a single critical mass frontier that needs to be reached in order to make the system self-sustained (as in nonspatial markets), and that this frontier is varying from one location to the next, depending on the density and distribution of the demand and supply over space and time. Identification of the critical mass frontier will allow for better evaluation of implementation policies and regulations.

Formation of the rear slope of the island arc of Chingiz Kaledonid ridge in eastern Kazakhstan

Process of formation of the island-arc rear slope is considered on the example of the Upper Cambrian–Middle Ordovician arc found in the Chingiz ridge in eastern Kazakhstan. Its occurrence is shown at the end of volcanic activity in the island-arc structure, beginning at the end of the early Arenig (from the end of the Flos century of the Early Ordovician) with tephroturbidites appearance. After the cessation of volcanism, two sedimentation cycles were distinguished in the sedimentary section of the slope in the middle Ordovician: (1) transgressive when the island arc submerged, (2) and regressive when the Chingiz arc began to build up at the beginning of the Llanwyrn (Darrivilian) century. The sedimentation was repeatedly accompanied by landslide processes, which ended in the middle of llanvirna (darrivilia) with the disruption of tectonic-gravity plate composed of Upper Cambrian volcanic rocks with limestone in the sole, resulting in the formation of coarsely fragmented mixtite at the allochthonous mass frontier, the further sedimentation on the rear slope stopped. Keywords: the island-arc; rear slope; sedimentation cycles; landslide processes