Peptide-enhanced mRNA transfection in cultured mouse cardiac fibroblasts and direct reprogramming towards cardiomyocyte-like cells.

The treatment of myocardial infarction is a major challenge in medicine due to the inability of heart tissue to regenerate. Direct reprogramming of endogenous cardiac fibroblasts into functional cardiomyocytes via the delivery of transcription factor mRNAs has the potential to regenerate cardiac tissue and to treat heart failure. Even though mRNA delivery to cardiac fibroblasts has the therapeutic potential, mRNA transfection in cardiac fibroblasts has been challenging. Herein, we develop an efficient mRNA transfection in cultured mouse cardiac fibroblasts via a polyarginine-fused heart-targeting peptide and lipofectamine complex, termed C-Lipo and demonstrate the partial direct reprogramming of cardiac fibroblasts towards cardiomyocyte cells. C-Lipo enabled the mRNA-induced direct cardiac reprogramming due to its efficient transfection with low toxicity, which allowed for multiple transfections of Gata4, Mef2c, and Tbx5 (GMT) mRNAs for a period of 2 weeks. The induced cardiomyocyte-like cells had α-MHC promoter-driven GFP expression and striated cardiac muscle structure from α-actinin immunohistochemistry. GMT mRNA transfection of cultured mouse cardiac fibroblasts via C-Lipo significantly increased expression of the cardiomyocyte marker genes, Actc1, Actn2, Gja1, Hand2, and Tnnt2, after 2 weeks of transfection. Moreover, this study provides the first direct evidence that the stoichiometry of the GMT reprogramming factors influence the expression of cardiomyocyte marker genes. Our results demonstrate that mRNA delivery is a potential approach for cardiomyocyte generation

Experimental study on the validity of flow region division

Einstein first proposed that a river flow can be divided into three parts, corresponding to the banks and its bed, respectively, but he did not explain why the flow is dividable and how to divide the flow, in other words the flow division is only a mathematical treatment to simplify his analysis. Since Einstein\u27s proposition there have been many researches and debates on this topic, many division lines have been proposed, but there is no specially designed experimental research to verify the physical existence of division lines, and these division lines have not been tested against the experimental data. For this purpose, an experiment in a rectangular open channel was conducted to measure whether zero-shear stress exists in an open channel except its existence on the free surface. The measured results reveal that zero-shear stress indeed exists below the free surface, and some proposed equations of division line agree well with the profile of the measured zero-shear line, thus it is clarified that Einstein\u27s hypothesis is not only useful to simplify the mathematical treatment, but also it has the physical basis, i.e., zero-shear division line. As far as the authors know, in the literature, this is the first experimental proof that the division lines indeed exist in channel flows

Potato: A Data-Oriented Programming 3D Simulator for Large-Scale Heterogeneous Swarm Robotics

Large-scale simulation with realistic nonlinear dynamic models is crucial for algorithms development for swarm robotics. However, existing platforms are mainly developed based on Object-Oriented Programming (OOP) and either use simple kinematic models to pursue a large number of simulating nodes or implement realistic dynamic models with limited simulating nodes. In this paper, we develop a simulator based on Data-Oriented Programming (DOP) that utilizes GPU parallel computing to achieve large-scale swarm robotic simulations. Specifically, we use a multi-process approach to simulate heterogeneous agents and leverage PyTorch with GPU to simulate homogeneous agents with a large number. We test our approach using a nonlinear quadrotor model and demonstrate that this DOP approach can maintain almost the same computational speed when quadrotors are less than 5,000. We also provide two examples to present the functionality of the platform.Comment: 4 pages, 5 figures, accepted by ICRA 2023 Workshop on "The Role of Robotics Simulators for Unmanned Aerial Vehicles

The Total Risk Analysis of Large Dams under Flood Hazards

Dams and reservoirs are useful systems in water conservancy projects; however, they also pose a high-risk potential for large downstream areas. Flood, as the driving force of dam overtopping, is the main cause of dam failure. Dam floods and their risks are of interest to researchers and managers. In hydraulic engineering, there is a growing tendency to evaluate dam flood risk based on statistical and probabilistic methods that are unsuitable for the situations with rare historical data or low flood probability, so a more reasonable dam flood risk analysis method with fewer application restrictions is needed. Therefore, different from previous studies, this study develops a flood risk analysis method for large dams based on the concept of total risk factor (TRF) used initially in dam seismic risk analysis. The proposed method is not affected by the adequacy of historical data or the low probability of flood and is capable of analyzing the dam structure influence, the flood vulnerability of the dam site, and downstream risk as well as estimating the TRF of each dam and assigning corresponding risk classes to each dam. Application to large dams in the Dadu River Basin, Southwestern China, demonstrates that the proposed method provides quick risk estimation and comparison, which can help local management officials perform more detailed dam safety evaluations for useful risk management information

Turbulence Kinetic Energy inside Suspended Vegetation Domain under Periodic Water Waves

10.1061/JWPED5.WWENG-1909JOURNAL OF WATERWAY PORT COASTAL AND OCEAN ENGINEERING149

Biodegradable Poly(acrylic acid-co-acrylamide)/Poly(vinyl alcohol) Double Network Hydrogels with Tunable Mechanics and High Self-healing Performance

We proposed a novel strategy in the fabrication of biodegradable poly(acrylic acid-co-acrylamide)/poly(vinyl alcohol) (P(AAc-co-Am)/PVA) double network (DN) hydrogels with good mechanical and self-healing properties. In the DN hydrogel system, P(AAc-co-Am) polymers form a network through the ionic coordinates between –COO– and Fe3+ and hydrogen bonding between –COOH and –CONH2, while another network is fabricated by the complexation between PVA and borax. The influences of the composition on the rheological behaviors and mechanical properties of the synthesized DN hydrogels were investigated. The rheological measurements revealed that the viscoelasticity and stiffness of the P(AAc-co-Am)/PVA DN hydrogels increase as the acrylamide and Fe3+ concentrations increase. At 0.05 mmol of Fe3+ and 50% of acrylamide, tensile strength and elongation at break of P(AAc-co-Am)/PVA DN hydrogels could reach 329.5 KPa and 12.9 mm/mm, respectively. These properties arise from the dynamic reversible bonds existed in the P(AAc-co-Am)/PVA DN hydrogels. These reversible bonds also give good self-healing properties, and the maximum self-healing efficiency of P(AAc-co-Am)/PVA DN hydrogels is up to 96.4%. The degradation test of synthesized DN hydrogels was also conducted under simulated physiological conditions and the weight loss could reach 74% in the simulated intestinal fluid. According to the results presented here, the synthesized P(AAc-co-Am)/PVA DN hydrogels have a potential application prospect in various biomedical fields

NANOG Is Multiply Phosphorylated and Directly Modified by ERK2 and CDK1 In Vitro

NANOG is a divergent homeobox protein and a core component of the transcriptional circuitry that sustains pluripotency and self-renewal. Although NANOG has been extensively studied on the transcriptional level, little is known regarding its posttranslational regulation, likely due to its low abundance and challenging physical properties. Here, we identify eleven phosphorylation sites on endogenous human NANOG, nine of which mapped to single amino acids. To screen for the signaling molecules that impart these modifications, we developed the multiplexed assay for kinase specificity (MAKS). MAKS simultaneously tests activity for up to ten kinases while directly identifying the substrate and exact site of phosphorylation. Using MAKS, we discovered site-specific phosphorylation by ERK2 and CDK1/CyclinA2, providing a putative link between key signaling pathways and NANOG