583 research outputs found
Order from Chaos: Single Cell Reprogramming in Two Phases
The generation of induced pluripotent stem cells (iPSCs) is considered to be stochastic with a minute fraction of cells becoming pluripotent. Recently in Cell, Buganim etĀ al. (2012) changed this view using single cell analyses to reveal a stochastic early and hierarchical late phase, with implications for productive alternative reprogramming strategies
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Endothelial cells derived from patients' induced pluripotent stem cells for sustained factor VIII delivery and the treatment of hemophilia A.
Hemophilia A (HA) is a bleeding disorder characterized by spontaneous and prolonged hemorrhage. The disease is caused by mutations in the coagulation factor 8 gene (F8) leading to factor VIII (FVIII) deficiency. Since FVIII is primarily produced in endothelial cells (ECs) in a non-diseased human being, ECs hold great potential for development as a cell therapy for HA. We showed that HA patient-specific induced pluripotent stem cells (HA-iPSCs) could provide a renewable supply of ECs. The HA-iPSC-derived ECs were transduced with lentiviral vectors to stably express the functional B domain deleted F8 gene, the luciferase gene, and the enhanced green fluorescent protein gene (GFP). When transplanted intramuscularly into neonatal and adult immune deficient mice, the HA-iPSC-derived ECs were retained in the animals for at least 10-16āweeks and maintained their expression of FVIII, GFP, and the endothelial marker CD31, as demonstrated by bioluminescence imaging and immunostaining, respectively. When transplanted into HA mice, these transduced HA-iPSC-derived ECs significantly reduced blood loss in a tail-clip bleeding test and produced therapeutic plasma levels (11.2%-369.2%) of FVIII. Thus, our studies provide proof-of-concept that HA-iPSC-derived ECs can serve as a factory to deliver FVIII for the treatment of HA not only in adults but also in newborns
Determinants of Continuance Intention to Use Mobile Payments in China
Mobile payments as a critical service supporting mobile businesses have received significant attention from enterprises. The rapid spread of COVID-19 resulted in the closure of many restaurants, shopping malls, and supermarkets. Meanwhile, mobile payments directly replace cash payment (Yin, Gong, and Pan 2019) and change peopleās consumption habits (Yin et al. 2019). Thus, it played an important role during the COVID-19 pandemic period when isolation measures were encouraged. With the booming mobile payments, the Chinese market has cultivated two giants and other mobile payments providers. In the competitive market environment, how to understand usersā requirements, enhance usersā product experience and enhance usersā stickiness is the key for enterprises to gain competitive advantages. The commercial value of mobile payments depends on the participation of more users and more using. Retaining existing mobile payment users would be subject to more attention from academic researchers and practitioners in this field. This research aims to apply the value-based adoption model (VAM), expectation-confirmation theory (ECM), and habit theory to investigate the factors affecting the usage continuance of mobile payments in China.
A mixed-method approach, which combined qualitative and quantitative research, is selected for this study. Qualitative research employed the critical incident technique (CIT) method in exploratory analysis to explore the dimensions and connotations of the perceived value of mobile payments. From the perspective of user-perceived benefits, it contains five dimensions: utilitarian value, hedonic value, social value, ecological value and health value. From the perspective of user-perceived sacrifices, it includes three dimensions: risk cost, based on mobile and low-level pain of payment. Quantitative research employed structural equation modelling (SEM) to identify the factors affecting the mobile payments continuance use in China under different constructs, both habit-related factors and product-related factors (i.e., utilitarian, hedonic, social and health).
Results showed that the significant factors directly affecting the intention to continue to use mobile payment services are habit and perceived utilitarian value. The findings also show that perceived hedonic value, perceived social value, and perceived health value all boost consumersā desire to continue using mobile payments indirectly via the mediation of customersā habits. These findings provide a direction for companies and developers of mobile payment services to encourage usersā continuance intention. The theoretical, methodological and practical contributions of this study, the generalisation aspects and limitation of this study, and the contexts of future research are discussed
Joint Optimization of DNN Inference Delay and Energy under Accuracy Constraints for AR Applications
The high computational complexity and high energy consumption of artificial
intelligence (AI) algorithms hinder their application in augmented reality (AR)
systems. This paper considers the scene of completing video-based AI inference
tasks in the mobile edge computing (MEC) system. We use multiply-and-accumulate
operations (MACs) for problem analysis and optimize delay and energy
consumption under accuracy constraints. To solve this problem, we first assume
that offloading policy is known and decouple the problem into two subproblems.
After solving these two subproblems, we propose an iterative-based scheduling
algorithm to obtain the optimal offloading policy. We also experimentally
discuss the relationship between delay, energy consumption, and inference
accuracy.Comment: 6 pages, 7 figures, accepted by Globecom202
Synthesis of Alkyl Substituted Dicyclohexano-18-crown-6 Homologues for Strontium Extraction in HNO3 Media
AbstractA series of dicyclohexano-18-crown-6 (DCH18C6) homologues containing different alkyl substituents were synthesized for a comparative study of the extraction ability towards strontium. The synthesis and the structure characterization of the intermediates and the products were detailed. The crown ether homologues were labeled as CX-DCH18C6 (X=3ā¼7), where the X represents the number of the carbon atoms in the alkyl substituents. The extraction ability of the CX-DCH18C6 samples towards strontium in solvent extraction system was investigated. The substituent effect of the samples was discussed, and the factors affecting the separation such as solvent, acidity and initial metal concentration were examined
Study on dynamic strength and liquefaction mechanism of silt soil in Castor earthquake prone areas under different consolidation ratios
Under the Castor earthquake, there is a risk of liquefaction instability of saturated tailings, and the evolution of dynamic pore pressure can indirectly reflect its instability process. Before applying dynamic loads, the static stress state of soil is one of the main factors affecting the development of soil dynamic strength and dynamic pore pressure, and there are significant differences in soil dynamic strength under different consolidation ratios. This paper conducted dynamic triaxial tests on saturated tailings silt with different consolidation ratios, and analyzed the dynamic strength variation and liquefaction mechanism of the samples using the discrete element method (PFC3D). The results showed that 1) as the Kcā² gradually increased, and there was a critical consolidation ratio Kcā² during the development of the dynamic strength of the sample. The specific value of Kcā² was related to the properties and stress state of saturated sand. The Kcā² in this research was about 1.9. When Kc < 1.9, dynamic strength was increased with the increase in Kc; when Kc > 1.9, dynamic strength was decreased with the Kc. 2) Under the impact of cyclic load, when samples were normally consolidated (Kc =1), the pore water pressure would tend to be equal to the confining pressure to cause soil liquefaction. In the case of eccentric consolidation (Kc > 1), the pore water pressure would be less than the confining pressure, thus, the soil liquefaction would not be induced, and the pore pressure value would decrease with the increase of consolidation ratio. This paper provides engineering guidance value for the study of dynamic strength and liquefaction mechanism of tailings sand and silt in Castor earthquake prone areas under different consolidation ratios
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