Exceptional mechanical properties and significant hydrophobicity are observed in the prepared, leakage-free paraffin/MSA composites, featuring a density of 0.70 g/cm³ and a contact angle of 122 degrees. Moreover, the paraffin/MSA composite's average latent heat is observed to reach a maximum of 2093 J/g, representing approximately 85% of the latent heat of pure paraffin. This value substantially surpasses that of other paraffin/silica aerogel phase-change composite materials. Despite the presence of MSA, the thermal conductivity of the paraffin/MSA blend remains virtually unchanged from that of the pure paraffin, approximately 250 mW/m/K, with no interference from the MSA skeletal structures. The results presented strongly support the utilization of MSA as a carrier material for paraffin, thereby extending its utility in thermal management and energy storage applications.
In the contemporary world, the damaging effects on agricultural soil, resulting from various elements, warrant serious attention from all. Employing accelerated electron crosslinking and grafting, a novel sodium alginate-g-acrylic acid hydrogel was simultaneously synthesized in this study, intended for soil remediation. The variables of irradiation dose and NaAlg content and their correlations to the gel fraction, network and structural parameters, sol-gel analysis, swelling power, and swelling kinetics of NaAlg-g-AA hydrogels were studied. It has been demonstrated that NaAlg hydrogels exhibit a substantial swelling capacity, which is highly contingent upon their chemical composition and the irradiation dose applied; these hydrogels' structures remain stable even when exposed to different pH conditions or varying water sources. Analysis of diffusion data indicated a non-Fickian transport mechanism, a characteristic feature of cross-linked hydrogels (061-099). read more Prepared hydrogels have proven to be outstanding choices for sustainable agricultural applications.
The gelation process of low-molecular-weight gelators (LMWGs) is significantly influenced by the Hansen solubility parameter (HSP). read more Although HSP-based techniques are common, they only differentiate solvents' gel-forming capabilities, which necessitates repeated tests for accurate classification. Quantitative estimations of gel properties using the HSP are highly desirable for engineering considerations. By employing three independent metrics—mechanical strength, light transmission, and the use of 12-hydroxystearic acid (12HSA) for organogel preparation—this study determined critical gelation concentrations and correlated them with solvent HSP values. The findings demonstrated a strong link between mechanical strength and the distance of 12HSA and solvent molecules in the HSP analysis. Lastly, the results suggested that a constant-volume-based concentration method is critical when comparing the characteristics of organogels to a different solvent. The gelation sphere of novel low-molecular-weight gels (LMWGs) within the high-pressure space (HSP) can be effectively determined using these findings, thereby facilitating the design of organogels with adaptable physical properties.
The utilization of natural and synthetic hydrogel scaffolds containing bioactive components is growing rapidly in the field of tissue engineering problem resolution. Transfecting agents, such as polyplexes, encapsulating DNA-encoding osteogenic growth factors within scaffold structures, represent a promising approach for sustained gene delivery to bone defects and corresponding protein production. This study, for the first time, presented a comparative evaluation of the in vitro and in vivo osteogenic properties of 3D-printed sodium alginate (SA) hydrogel scaffolds, which were impregnated with model EGFP and therapeutic BMP-2 plasmids. An analysis of the expression levels of mesenchymal stem cell (MSC) osteogenic differentiation markers Runx2, Alpl, and Bglap was conducted using real-time PCR. A study of in vivo osteogenesis, employing micro-CT and histomorphology, was conducted on a critical-sized cranial defect in Wistar rats. read more The 3D cryoprinting of pEGFP and pBMP-2 plasmid polyplexes, combined with the SA solution, does not compromise their ability to transfect cells, exhibiting identical performance to the initial compounds. Histomorphometric and micro-CT imaging, eight weeks following scaffold implantation, displayed a noteworthy (up to 46%) elevation in new bone formation for the SA/pBMP-2 group relative to the SA/pEGFP group.
Hydrogen production using water electrolysis, though technically sound, is plagued by the expensive and limited availability of noble metal electrocatalysts, making large-scale production challenging. Electrocatalysts of cobalt-anchored nitrogen-doped graphene aerogels (Co-N-C), intended for oxygen evolution reaction (OER), are produced through a simple chemical reduction and vacuum freeze-drying process. At 10 mA/cm2, the Co (5 wt%)-N (1 wt%)-C aerogel electrocatalyst delivers an optimal overpotential of 0.383 V, dramatically exceeding the performance observed in a series of M-N-C aerogel electrocatalysts (M = Mn, Fe, Ni, Pt, Au, etc.) produced via a similar process and previously documented Co-N-C electrocatalysts. Moreover, the Co-N-C aerogel electrocatalyst displays a small Tafel slope (95 mV/decade), a large electrochemical surface area (952 cm2), and impressive durability. The Co-N-C aerogel electrocatalyst, at a current density of 20 mA/cm2, showcases an overpotential that eclipses the performance of the commercial RuO2. Density functional theory (DFT) confirms the hierarchical metal activity order of Co-N-C, followed by Fe-N-C, and lastly Ni-N-C, which is in complete accordance with the experimental results for OER activity. The simple preparation method, abundant source materials, and outstanding electrocatalytic activity of Co-N-C aerogels make them a highly promising electrocatalyst for energy storage and conservation.
Degenerative joint disorders, like osteoarthritis, find promising prospects in tissue engineering, thanks to the substantial potential of 3D bioprinting. Despite the need for bioinks that promote cell growth and differentiation, protecting cells from oxidative stress, a hallmark of osteoarthritis, remains a significant hurdle. In this study, an anti-oxidative bioink, derived from an alginate dynamic hydrogel, was developed to counteract the cellular phenotype changes and malfunctions brought on by oxidative stress. The phenylboronic acid-modified alginate (Alg-PBA), through a dynamic covalent bond with poly(vinyl alcohol) (PVA), prompted the rapid gelation of the alginate dynamic hydrogel. Because of its dynamic feature, the substance demonstrated significant self-healing and shear-thinning aptitudes. The alginate backbone's carboxylate groups, crosslinked ionically with introduced calcium ions via a secondary method, maintained the dynamic hydrogel's capacity for long-term mouse fibroblast growth. In a further observation, the dynamic hydrogel demonstrated good printability, thus allowing for the creation of scaffolds with cylindrical and grid formations, displaying impressive structural accuracy. Mouse chondrocytes, encapsulated within a bioprinted hydrogel, demonstrated sustained high viability for at least seven days following ionic crosslinking. The bioprinted scaffold's ability to reduce intracellular oxidative stress in H2O2-exposed embedded chondrocytes, as demonstrated in in vitro studies, is significant; it also protected chondrocytes from H2O2-mediated decrease in anabolic genes (ACAN and COL2) associated with the extracellular matrix and increase in the catabolic gene MMP13. The results suggest that the dynamic alginate hydrogel can be effectively utilized as a versatile bioink for the creation of 3D bioprinted scaffolds possessing inherent antioxidative properties. This procedure is anticipated to improve the restorative capabilities of cartilage tissues, facilitating the treatment of joint disorders.
Bio-based polymers are garnering considerable attention, thanks to their potential for diverse applications, substituting traditional polymers. The electrolyte is a crucial element in electrochemical devices, and polymeric materials are strong contenders for developing solid-state and gel electrolytes, essential to the advancement of full-solid-state devices. The report examines the fabrication and characterization of uncrosslinked and physically cross-linked collagen membranes, exploring their potential as a polymeric material for the development of a gel electrolyte. The assessment of membrane stability in water and aqueous electrolyte, along with mechanical characterization, showed cross-linked samples to have a suitable balance between water absorption and resistance properties. After an overnight exposure to sulfuric acid, the cross-linked membrane exhibited optical characteristics and ionic conductivity, highlighting its potential as an electrochromic device electrolyte. To verify the concept, an electrochromic device was fabricated by placing the membrane (after being dipped in sulfuric acid) between a glass/ITO/PEDOTPSS substrate and a glass/ITO/SnO2 substrate. The cross-linked collagen membrane, as assessed by its optical modulation and kinetic performance, shows promise as a water-based gel and bio-based electrolyte material for use in full-solid-state electrochromic devices.
Gel fuel droplets experience disruptive burning as a consequence of their gellant shell's rupture. This rupture leads to the expulsion of unreacted fuel vapors from the droplet's interior, emerging as jets into the flame. Beyond simple vaporization, the jetting mechanism promotes convective fuel vapor transport, leading to faster gas-phase mixing and improved droplet combustion rates. The viscoelastic gellant shell surrounding the droplet, as observed through high-magnification and high-speed imaging, dynamically evolves throughout the droplet's lifetime, causing intermittent bursts at differing frequencies, thus initiating a time-dependent oscillatory jetting. A non-monotonic (hump-shaped) trend in droplet bursting is evident in the continuous wavelet spectra of droplet diameter fluctuations, characterized by an initial increase and subsequent decrease in bursting frequency until oscillation stops.