ARTICLE | doi:10.20944/preprints201801.0032.v2
Subject: Earth Sciences, Environmental Sciences Keywords: triggering of debris flows; overland flow; infiltration; laboratory experiments; modelling; rain intensity-duration threshold curves
Online: 13 June 2018 (08:37:32 CEST)
Many studies, which try to analyze conditions for debris flow development, ignore the type of initiation. Therefore this paper deals with the following questions: What type of hydro-mechanical triggering mechanisms for debris flows can we distinguish in upstream channels of debris flow prone gullies? Which are the main parameters controlling the type and temporal sequence of these triggering processes and what is their influence on the meteorological thresholds for debris flow initiation? A series of laboratory experiments were carried out in a flume, 8 m long and with a width of 0.3 m. to detect the conditions for different types of triggering mechanisms. The flume experiments show a sequence of hydrological processes triggering debris flows, namely erosion and transport by intensive overland flow and by infiltrating water causing failure of channel bed material. On the basis of these experiments an integrated hydro-mechanical model was developed, which describes Hortonian and Saturation overland flow, maximum sediment transport, through flow and failure of bed material. The model was calibrated and validated using process indicator values measured during the experiments in the flume. Virtual model simulations, carried out in a schematic hypothetical source area of a catchment show that slope angle and hydraulic conductivity of the bed material determine the type and sequence of these triggering processes. It was also clearly demonstrated that the type of hydrological triggering process and the influencing geometrical and hydro-mechanical parameters may have a great influence on rainfall intensity-duration threshold curves for the start of debris flows.
Subject: Chemistry, Applied Chemistry Keywords: PVG (polyvinyl Guanidineacetic); PVA (polyvinyl alcohol); guanidineacetic groups; biodiesel; transesterification
Online: 21 September 2019 (01:38:06 CEST)
Polyvinyl guanidineacetic (PVG) was prepared by the chemical grafting between poly(vinyl alcohol) (PVA) and guanidineacetic acid. The results showed that the guanidineacetic groups were successfully introduced into the polyvinyl alcohol by fourier transform infrared (FTIR) and thermogravimetry (TG). The effects of the amount of catalyst and reaction time on the PVG grafting rate were investigated. The PVG/NWF composite membrane as a heterogeneous catalyst for biodiesel production was successfully prepared by the solvent phase inversion. The effects of mass ratio of methanol/soybean oil and reaction temperature on the conversions using the composite membrane for transesterification were studied. And the reusability of the composite membrane and the kinetics of the reaction catalyzed by the composite membrane were also investigated. The conversions obtained from the model are in good agreement with the experimental data.
ARTICLE | doi:10.20944/preprints201706.0128.v1
Subject: Chemistry, Medicinal Chemistry Keywords: steroidal dimer; steroidal N-heterocycles; antiproliferative activity; esophageal cancer cells
Online: 30 June 2017 (07:43:06 CEST)
Following our previous success in identifying new steroid-based anticancer agents, we herein disclosed the structural requirements for retaining high potency against cancer cells and associated modes of action. The structurally novel steroidal dimer by001 inhibited growth of different esophageal cancer cells and colony formation at low micromolar levels, elevated cellular ROS levels and caused mitochondrial dysfunction. Mechanistic studies showed that by001 induced cell death through the mitochondria and death receptor-mediated apoptotic pathways and autophagy induction, as well as inhibited migration.
Subject: Engineering, Automotive Engineering Keywords: Pyrolysis; Life cycle assessment; Techno-economic assessment; sludge
Online: 26 July 2021 (10:06:50 CEST)
The increasing amount of municipal sludge in China requires safe and effective management to protect human health and ensure environmental sustainability. Pyrolysis is a thermochemical process that that decompose organic matter at elevated temperature and under anaerobic conditions, and it has attracted an increasing attention in sludge treatment in the recent years. However, comprehensive environmental and economic assessment of sludge pyrolysis in China's context is rare, due to the small quantities of full-scale sludge pyrolysis plant. In this paper, we applied our design and operation parameters of full-scale sludge pyrolysis plants to generate the material and energy consumptions of the pyrolysis system under various of conditions, including sludge organic content and moisture content, system size, system energy distribution, and whether or not heat substitution is applied. Life cycle assessment and techno-economic assessment were then applied to investigate the environmental and economic performance of the system Our results demonstrate the significant environmental and economic impacts associated with sludge properties and system size. Generally, sludge with higher organic content and lower moisture content requires less natural gas consumption, which leads to a simultaneous improvement of the system environmental and economic performance. The system economic performance is more sensitive to the system size, and centralized sludge handling using a larger pyrolysis is more economic favorable. In the most ideal case, the average global warming potential and minimum sludge handling price of sludge pyrolysis could be as low as -32.5 kg CO2-Eq/t DS and 188.8 $/t DS, respectively. Based on these results, we discussed the pathways that could be taken to further optimize the environmental and economic performances of the pyrolysis system.
ARTICLE | doi:10.20944/preprints201708.0023.v1
Subject: Medicine & Pharmacology, Oncology & Oncogenics Keywords: CBFA2T2; renal cell carcinoma; cancer stem cells; OCT-4; NANOG
Online: 7 August 2017 (15:22:50 CEST)
Renal cell carcinoma (RCC) is the most common kidney cancer, accounting for approximately 80–90 % of all primary kidney cancer. Treatment for patients with advanced RCC remains unsatisfactory. Rare cancer stem cells (CSCs) are proposed to be responsible for failure of current treatment. Here, we investigate the effects of CBFA2T2 on CSCs regulation in RCC, as well as to elucidate the possible mechanisms. We showed that CBFA2T2 expression can significantly predict the survival of RCC patients. Functional assays showed that knocking-down of CBFA2T2 can inhibit cell migration and invasion in 786-O and A-498 cells in vitro, and reduce ALDHhigh CSCs populations. Furthermore, CBFA2T2 expression is necessary for sphere-forming ability and cancer stem cells marker expression in RCC cell lines. Collectively, our data suggest that CBFA2T2 expression correlates with aggressive characteristics of RCC and CBFA2T2 is required for maintenance of “stemness” through regulation of stem cells factors, thereby highlighting CBFA2T2 as a potential therapeutic target for RCC treatment.