Regulation of cardiac fibroblasts reprogramming into cardiomyocyte-like cells with a cocktail of small molecule compounds.

Myocardial infarction results in extensive cardiomyocyte apoptosis, leading to the formation of noncontractile scar tissue. Given the limited regenerative capacity of adult mammalian cardiomyocytes, direct reprogramming of cardiac fibroblasts (CFs) into cardiomyocytes represents a promising therapeutic strategy for myocardial repair, and small molecule drugs might offer a more attractive alternative to gene editing approaches in terms of safety and clinical feasibility. This study aimed to reprogram rat CFs into cardiomyocytes using a small molecular chemical mixture comprising CHIR99021, Valproic acid, Dorsomorphin, SB431542, and Forskolin. Immunofluorescence analysis revealed a significant increase in the expression of cardiomyocyte-specific markers, including cardiac troponin T (cTnT), Connexin 43 (Cx43), α-actinin, and Tbx5. Changes in intracellular calcium ion levels and Ca2+ signal transfer between adjacent cells were monitored using a calcium ion fluorescence probe. mRNA sequencing analysis demonstrated the upregulation of genes associated with cardiac morphogenesis, myocardial differentiation, and muscle fiber contraction during CF differentiation induced by the small-molecule compounds. Conversely, the expression of fibroblast-related genes was downregulated. These findings suggest that chemical-induced cell fate conversion of rat CFs into cardiomyocyte-like cells is feasible, offering a potential therapeutic solution for myocardial injury.

Fibroblast growth factor 2 acts as an upstream regulator of inhibition of pulmonary fibroblast activation.

Fibroblast growth factor (FGF) signaling plays a crucial role in lung development and repair. Fibroblast growth factor 2 (FGF2) can inhibit fibrotic gene expression and suppress the differentiation of pulmonary fibroblasts (PFs) into myofibroblasts in vitro, suggesting that FGF2 is a potential target for inhibiting pulmonary fibrosis. To gain deeper insights into the molecular mechanism underlying FGF2-mediated regulation of PFs, we performed mRNA sequencing analysis to systematically and globally uncover the regulated genes and biological functions of FGF2 in PFs. Gene Ontology analysis revealed that the differentially expressed genes regulated by FGF2 were enriched in multiple cellular functions including extracellular matrix (ECM) organization, cytoskeleton formation, ß-catenin-independent Wnt signaling pathway, supramolecular fiber organization, epithelial cell proliferation, and cell adhesion. Gene Set Enrichment Analysis and cellular experiments confirmed that FGF2 can suppress ECM and actin filament organization and increase PFs proliferation. Taken together, these findings indicate that FGF2 acts as an upstream regulator of the inhibition of PFs activation and may play a regulatory role in pulmonary fibrosis.

Investigating the spatial distribution of polychlorinated biphenyls in sediment in the Pearl River Delta, South China.

One hundred forty-three surface sediment (0-5 cm depth) samples were collected from locations representing industrialized areas, less-industrialized areas, and e-waste recycling areas in the Pearl River Delta (PRD). The spatial distribution of polychlorinated biphenyls (PCBs) and their potential adverse effects on aquatic organisms were investigated. The average PCB concentration in the less-industrialized areas (background) in the PRD was approximately 10 ng/g dry weight (dw), which was generally half that found in the industrialized areas (approximately 22 ng/g dw). Severe PCB contamination, with concentrations ranging from 1000 to 26500 ng/g dw, was found in pond sediments collected from e-waste recycling areas. It is very likely that such contamination would have had adverse effects on the aquatic biota there. PCBs in the e-waste recycling areas were dominated by penta- and hex-PCB congeners, which made them significantly different from those found in other regions, where tri- and tetra-PCB congeners were predominant. Higher abundances of less chlorinated congeners were seen in the less-industrialized areas compared to the industrialized areas. Differences in the transport abilities of different congeners, together with dechlorination of higher chlorinated congeners, is the most likely reasons for this.

Facile synthesis of a novel transparent hyperbranched phosphorous/nitrogen-containing flame retardant and its application in reducing the fire hazard of epoxy resin.

In this study, a novel hyperbranched phosphorus/nitrogen-containing flame retardant (HPNFR) was facilely synthesized via the transesterification reaction of dimethyl methylphosphonate and tris (2-hydroxyethyl) isocyanurate and characterized successfully by 1H NMR and FTIR. The sample with 4 wt% HPNFR can achieve V-0 rating in UL-94 test and possess a LOI value as high as 34.5%. Conspicuous blowing-out effect was observed during the vertical burning test. TG results indicated that the presence of HPNFR significantly improved the thermal stability of EP thermosets. From cone test, THR, p-HRR, p-SPR and TSP values of HPNFR/EP composites were decreased in comparison to those of pure EP, revealing the reduced fire hazard of EP composites with HPNFR. SEM images of EP thermoset with 4 wt% of HPNFR after cone test exhibited compact and continuous char layers, while those of pure EP are fragmentary and broken. From TG-IR test, the yield of toxic CO and other pyrolysis products was significantly reduced, indicating a decrease in toxicity. Phosphorus-containing compounds were detected in gas phase, which verified the gaseous phase flame retardant effect of HPNFR. Besides, HPNFR would not significantly damage the transparence of EP thermosets, consequently reserved it's application value in some special fields.

Density Effect on Flame Retardancy, Thermal Degradation, and Combustibility of Rigid Polyurethane Foam Modified by Expandable Graphite or Ammonium Polyphosphate.

The current study aims at comparatively investigating the effect of apparent density on flame retardancy, thermal degradation and combustion behaviors of rigid polyurethane foam (RPUF), RPUF/ expandable graphite (EG) and RPUF/ ammonium polyphosphate (APP). A series of RPUF, RPUF/EG and RPUF/APP samples with different apparent densities (30, 60 and 90 kg/m³) were prepared. The flame retardancy, thermal degradation, and combustion behaviors of each sample were investigated. Limiting oxygen index (LOI) results indicated that increasing apparent density was beneficial to the flame retardancy of all foam systems. The effect of apparent density on the enhancement of flame retardancy followed the sequence of RPUF < RPUF/APP < RPUF/EG. Thermogravimetric analysis (TGA) results showed that an increase in the apparent density can cause more weight loss in the first degradation stage and less weight loss in the second degradation stage for all foam systems. The combustion behaviors also showed significant differences. The samples with a higher apparent density showed a longer duration of heat release and higher total heat release (THR). The findings in this study demonstrated that apparent density played an important role in flame retardancy, thermal degradation, and combustion behaviors of RPUF, which must be paid more attention in the studies of flame-retardant RPUF.

Mechanical, thermal and fire performance of an inorganic-organic insulation material composed of hollow glass microspheres and phenolic resin.

HYPOTHESIS: Organic foamy materials possess good thermal insulation properties and inorganic materials are non-combustible. Hence, it is possible to develop a kind of organic-inorganic lightweight thermal insulation materials with excellent fire safety. EXPERIMENTS: Hollow glass microsphere (HGM), as one kind of lightweight noncombustible inorganic material, was chosen as the filling material. Phenolic resin (PR), as the flame retardant polymeric material, was used as binding material. A series of HGM/PR composites with various PR/HGM mass ratio were prepared. Properties, such as apparent density, microstructure, mechanical strength, thermal conductivity, burning behavior and flame retardancy of the specimens were determined, respectively. FINDINGS: The results show that the surface of HGM particles is coated by a layer of cured PR and the HGM powder is glued together firmly from the scanning electron microscope (SEM) images. With the increase of PR/HGM mass ratio, both of apparent density and mechanical strength of HGM/PR composites increase, but thermal conductivity and limiting oxygen index (LOI) values decrease, all of the specimens still possess high LOI value (>50%). What's more, no flaming combustion (merely partial carbonization) and hardly any smoke can be observed during the burning process, which indicates the HGM/PR composites possess excellent flame retardant property and fire safety.

Fabrication of near-infrared-emitting CdSeTe/ZnS core/shell quantum dots and their electrogenerated chemiluminescence.

New water-soluble CdSeTe/ZnS core-shell quantum dots with excellent near-infrared emission were synthesized via an aqueous solution method; they showed strong electrogenerated chemiluminescence and favorable biocompatibility.