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Cardiac differentiation of embryonic stem cells (ESCs) can give rise to de novo chamber cardiomyocytes and nodal pacemaker cells. Compared with our understanding of direct differentiation toward atrial and ventricular myocytes, the mechanisms for nodal pacemaker cell commitment are not well understood. Taking a cue from the prominence of canonical Wnt signaling during cardiac pacemaker tissue development in chick embryos, we asked if modulations of Wnt signaling influence cardiac progenitors to bifurcate to either chamber cardiomyocytes or pacemaker cells. Omitting an exogenous Wnt inhibitor, which is routinely added to maximize cardiac myocyte yield during differentiation of mouse and human ESCs, led to increased yield of spontaneously beating cardiomyocytes with action potential properties similar to those of native sinoatrial node pacemaker cells. The pacemaker phenotype was accompanied by enhanced expression of genes and gene products that mark nodal pacemaker cells such as Hcn4, Tbx18, Tbx3, and Shox2. Addition of exogenous Wnt3a ligand, which activates canonical Wnt/β-catenin signaling, increased the yield of pacemaker-like myocytes while reducing cTNT-positive pan-cardiac differentiation. Conversely, addition of inhibitors of Wnt/β-catenin signaling led to increased chamber myocyte lineage development at the expense of pacemaker cell specification. The positive impact of canonical Wnt signaling on nodal pacemaker cell differentiation was evidenced in direct differentiation of two human ESC lines and human induced pluripotent stem cells. Our data identify the Wnt/β-catenin pathway as a critical determinant of cardiac myocyte subtype commitment during ESC differentiation: endogenous Wnt signaling favors the pacemaker lineage, whereas its suppression promotes the chamber cardiomyocyte lineage.

Differential RNA expression is becoming increasingly valuable in evaluating tumor heterogeneity for a better understanding of malignant tumors and guiding personalized therapy. However, traditional techniques for analyzing cellular RNA are mainly focused on determining the absolute level of RNA, which may lead to inaccuracies in understanding tumor heterogeneity, primarily due to i) the subtle differences in certain RNA types that have similar total concentrations and ii) the existence of variations in RNA expression across different samples. Herein, a detachable DNA assembly module is proposed that is capable not only of quantifying the expression level of target RNA but also of innovatively evaluating its proportion within its RNA family population through a sequential assembly and disassembly route. Using the let‐7 family as an experimental model, a significant difference is discovered in let‐7a proportion between normal mammary epithelial cells and breast cancer cells, a characteristic that is often missed in bulk analysis of traditional techniques. By combining concentration and proportion information, the detachable DNA assembly module demonstrates markedly higher efficiency in discerning among various types of cells compared to traditional techniques. This innovative assembly module is expected to offer a new perspective to highlight tumor heterogeneity and guide personalized therapy. [ABSTRACT FROM AUTHOR]

Wnt/β-catenin signaling has been shown to regulate gene expressions in cardiomyocytes. However, it is not known if this effect is dependent on the sex of cells or the glucose level in the culture medium. In the present study, ventricular myocytes were prepared from male and female neonatal rats and maintained in either a glucose-rich (25 mM) medium or a low-glucose (3 mM), lipid-rich medium. Real-time quantitative PCR was used to measure changes in target genes (Axin2, Scn5a, and Tbx3) after treatment with 1, 3, or 10 µM of CHIR-99021, an activator of Wnt/β-catenin signaling. CHIR induced similar changes in Axin2, Tbx3, and Scn5a transcripts in male and female NRVMs in both media, suggesting the absence of sex difference. However, cells in a high-glucose medium showed greater increases in Axin2 and Tbx3 transcripts than cells in a low-glucose medium. In addition, a low concentration of CHIR (1 µM) reduced the Scn5a transcript in cells in a high-glucose medium but not in a low-glucose medium, suggesting an increased sensitivity to Wnt signaling by high glucose. A non-linear relationship was identified between Axin2 transcript upregulation and Scn5a transcript downregulation in CIHR-treated NRVMs. These data suggest that high glucose sensitizes both male and female cardiomyocytes to Wnt/β-catenin signaling. [ABSTRACT FROM AUTHOR]

Degradation of Gram-positive bacterial cell wall peptidoglycan in macrophage and dendritic cell phagosomes leads to activation of the NLRP3 inflammasome, a cytosolic complex that regulates processing and secretion of interleukin (IL)-1β and IL-18. While many inflammatory responses to peptidoglycan are mediated by detection of its muramyl dipeptide component in the cytosol by NOD2, we report here that NLRP3 inflammasome activation is caused by release of N-acetylglucosamine that is detected in the cytosol by the glycolytic enzyme hexokinase. Inhibition of hexokinase by N-acetylglucosamine causes its dissociation from mitochondria outer membranes, and we found that this is sufficient to activate the NLRP3 inflammasome. In addition, we observed that glycolytic inhibitors and metabolic conditions affecting hexokinase function and localization induce inflammasome activation. While previous studies have demonstrated that signaling by pattern recognition receptors can regulate metabolic processes, this study shows that a metabolic enzyme can act as a pattern recognition receptor. PAPERCLIP.

To promote the safe and efficient mining of intelligent comprehensive mining under complex geological conditions, taking the geological structure of 3124S intelligent comprehensive mining face of Longtan Coal Power Company as the background, the structural conditions and mining difficulties are comprehensively analyzed. A series of complete technical schemes are made, including the structural form of geological borehole detection, surrounding rock structure reinforcement by grouting borehole, optimization and transformation of roadway system, advance laying of high-rise false roof, supplement and strengthen of disaster management, intelligent mining of rock breaking by coal machine, etc. Through the field practice, the output of geological structural section for intelligent fully-mechanized mining does not reduced, and the safety is guaranteed.

Crosslinked high-density polyethylene (XL-HDPE) is a preferred material for chemical and fuel tanks due to its superior environmental stress crack resistance and impact strength. The impact performance of rotationally molded specimen is important for final products. In the research the drop weight impact strength (defined as ARM impact strength) of rotationally molded XL-HDPE is tested between -40[degrees]C and 25[degrees]C. The crosslinking content, crystallization characteristics, and dynamic mechanical properties (DMA) of different thickness gradients are examined to illustrate the relationships between the impact strength, brittle-ductile transition (BDT) and microstructures. The innermost surface layer (about 0.3 mm) has lower gel content, higher crystallinity, and average lamellar thickness compared with the body part. The ARM impact strength is about 1 J/mm at -40[degrees]C and -30[degrees]C, and about 29 J/mm at -20[degrees]C ~ 25[degrees]C. There is a BDT between -30[degrees]C and--20[degrees]C. After removing the innermost surface layer, the sample breaks in ductile manner in the entire tested temperature range, and the ARM impact strength is about 24 ~ 26 J/ mm. The DMA results show that the BDT is consistent with the structure transition of the innermost surface layer. The microstructures of rotationally molded XL-HDPE in the innermost surface layer dominate the low temperature impact performance. KEYWORDS brittle, crosslinking, crystal structures, crystallization, fatigue analysis, fracture, polyethylene, processing, structure-property relations, transmission electron microscopy, 1 | INTRODUCTION Rotational molding is a processing method for manufacturing hollow plastic parts by adding plastic powder to a shell-like mold and rotating the mold about two axes while [...]

Three kinds of ethylene-octene copolymers (POE) were melt-blended with high-density polyethylene (PE-HD) in different proportions. Detailed characterizations were conducted to analyze their structural differences of POE and its effects in toughening PE-HD. The higher molecular weight POE can improve the toughness of PE-HD. 60:40 PE-HD/POE is elongated to break up to 700% while impact strength is 84.7 kJ/[m.sup.2] at -30[degrees]C, which is 21-fold of PE-HD. In the brittle to ductile transition (BDT) during impact, the fracture mechanism changes from the crazing mode to the shear yield-plastic deformation mode. The BDT temperature decreases as the POE molecular weight and its content increase. The interface strength in tension is estimated to access their effects. The Boltzmann-type models were successfully extended to describe the typical S-shaped curves in BDT of notched impact strength vs POE content or temperature. The supplementary decay model is suggested for the attenuation in toughening. Transition map in impact is proposed to select the use range of composition (c) and temperature (T) for high toughness. The curves are converted into 3D graph of T-c-impact strength for illustrating their coupling-separate effects, and further into the contour map of impact strength in T-c space for finding their partial equivalence. KEYWORDS brittle to ductile transition model, elastic-viscoplastic, fractography, impact testing, polymeric materials, 1 | INTRODUCTION High-density polyethylene (PE-HD) is widely used for being light and cheap with excellent processing performance and good weather resistance. [1] In fact, PE-HD is often used in [...]