Search Results (123)

This study investigates the influence of hybrid filler systems comprising carbon black (CB), mica, and surface-modified mica (SM) on the properties of ethylene–propylene–diene monomer (EPDM)/butadiene rubber (PB) composites. To reduce the environmental issues associated with CB, mica was incorporated as a partial substitute, and its compatibility with the rubber matrix was enhanced through surface modification using ureidopropyltrimethoxysilane (URE). The composites with hybrid filler systems and surface modification were evaluated in terms of curing behavior, crosslink density, mechanical and elastic properties, and dynamic viscoelasticity. Rheological analysis revealed that high mica loadings delayed vulcanization due to reduced thermal conductivity and accelerator adsorption, whereas SM composites maintained comparable curing performance. Swelling tests showed a reduction in crosslink density with increased unmodified mica content, while SM-filled samples improved the network density, confirming enhanced interfacial interaction. Mechanical testing demonstrated that the rubber compounds containing SM exhibited average improvements of 17% in tensile strength and 20% in toughness. In particular, the CB20/SM10 formulation achieved a well-balanced enhancement in tensile strength, elongation at break, and toughness, surpassing the performance of the CB-only system. Furthermore, rebound resilience and Tan δ analyses showed that low SM content reduced energy dissipation and improved elasticity, whereas excessive filler loadings led to increased hysteresis. The compression set results supported the thermal stability and recovery capacity of the SM-containing systems. Overall, the results demonstrated that the hybrid filler system incorporating URE-modified mica significantly enhanced filler dispersion and rubber–filler interaction, offering a sustainable and high-performance solution for elastomer composite applications. Full article

To advance the development of protein-rich plant-based foods, a novel binder system for vegan sausage alternatives without the requirement of heat application was investigated. This enables long-term ripening of plant-based analogs similar to traditional fermented meat or dairy products, allowing for refined flavor and texture development. This was achieved by using a poorly water-soluble calcium source (calcium carbonate) to introduce calcium ions into a low-ester pectin—gluten matrix susceptible to crosslinking via divalent ions. The gelling reaction of pectin–gluten dispersions with Ca²⁺ ions was time-delayed due to the gradual production of lactic acid during fermentation. Firm, sliceable matrices were formed, in which particulate substances such as texturized proteins and solid vegetable fat could be integrated, hence forming an unheated raw-fermented plant-based salami-type sausage model matrix which remained safe for consumption over 21 days of ripening. Gluten as well as pectin had a significant influence on the functional properties of the matrices, especially water holding capacity (increasing with higher pectin or gluten content), hardness (increasing with higher pectin or gluten content), tensile strength (increasing with higher pectin or gluten content) and cohesiveness (decreasing with higher pectin or gluten content). A combination of three simultaneously occurring effects was observed, modulating the properties of the matrices, namely, (a) an increase in gel strength due to increased pectin concentration forming more brittle gels, (b) an increase in gel strength with increasing gluten content forming more elastic gels and (c) interactions of low-ester pectin with the gluten network, with pectin addition causing increased aggregation of gluten, leading to strengthened networks. Full article

Background/Objectives: To evaluate the efficacy and safety of using the preservative-free topical proxymetacaine hydrochloride (Minims, 0.5% w/v, Bausch & Lomb, UK) to control postoperative pain after epithelium-off corneal crosslinking (CXL) for keratoconus. Methods: This is an observational study of patients with mild to severe keratoconus who have undergone epithelium-off CXL. CXL was completed by applying dextran-free riboflavin (0.1%) for 10 min (Vibex Rapid; Avedro, Inc.), followed by continuous UV-A light (Avedro KXL system; Avedro, Inc.) for 30 min at an intensity of 3 mW/cm² and an energy of 5.4 J/cm². All patients were prescribed postoperative proxymetacaine hydrochloride PRN with an allowed frequency of up to eight times per 24 h for the first 3 days to control postoperative pain. Patients were reviewed at 1–2 weeks postoperatively for a comprehensive examination, including assessment of delayed corneal healing, removal of the bandage contact lens, and recording of subjective symptoms. Results: There were 223 eyes of 180 patients with a mean age of 24.9 ± 8.6 years (range: 13–38 years). Male patients were 72%. At their planned first postoperative visit, we found no corneal healing abnormalities, such as persistent epithelial defects, epithelial irregularities, or early postoperative stromal haze, in any patient. All patients subjectively reported that proxymetacaine drops helped them to control postoperative pain, particularly in the first 48 h. Conclusions: None of the patients reported pain after 3 days of using proxymetacaine drops up to eight times a day for the first 3 days. It appears to be a safe and effective solution to control postoperative pain without any complications. Full article

The development of thermally stable fracturing fluids is essential for the effective stimulation of deep and low-permeability reservoirs. The stabilizing additives used in these fluids typically fall into three categories: crosslinking delay molecules, oxygen scavengers, and pH buffers. However, many conventional additives raise toxicity and environmental concerns, prompting the search for safer alternatives. This study investigates the use of sugar alcohols, commonly used as low-calorie sweeteners, as environmentally responsible additives for high-temperature fracturing fluids. A guar-based fluid system was formulated at a pH of 10 and evaluated using a high-pressure high-temperature (HPHT) rheometer under simulated field pumping conditions at 300 °F for a 90 min period. The viscosity was measured at a shear rate of 100 s⁻¹, with intermittent low-shear rates introduced to assess the structural recovery and fluid integrity. The effect of sugar alcohol concentration on crosslinking delay was examined across systems containing varying amounts of a zirconium-based crosslinker ranging from 1 to 4 gpt. The results demonstrated that sugar alcohols effectively delayed crosslinking, allowing for controlled viscosity development and improved stability at elevated temperatures. When optimized at concentrations of 2 ppt of the sugar alcohol with 4 gpt of the crosslinker, the fluid generated a peak viscosity of 600 cP after 2.5 min and maintained a viscosity above 300 cP throughout the 90 min test. Breaker results showed a controlled viscosity reduction, with final viscosity values reaching 10 cP. The proppant settling experiments confirmed the suspension of more than 95% of the proppant during the treatment window. These findings highlight the potential of sugar alcohols as effective and environmentally safer crosslinking delay additives for hydraulic fracturing applications. Full article

Yak meat jerky, a traditional high-protein food commonly consumed in high-altitude regions, is often produced via air-drying, which may adversely affect its nutritional quality and digestibility. This study systematically compared the gastrointestinal digestion profiles of air-dried yak meat (ADM) and vacuum freeze-dried yak meat (VFDM) using a dynamic in vitro human stomach–intestine (DHSI-IV) system. Key digestive parameters, including gastric emptying kinetics, particle size distribution, and protein hydrolysis, were evaluated under physiologically relevant conditions. VFDM exhibited superior hydration capacity, contributing to delayed gastric emptying of the mixed solid–liquid phase (t_1/2 = 85.1 ± 1.0 min) compared to ADM (t_1/2 = 80.4 ± 1.2 min), indicating increased gastric satiety. Conversely, VFDM showed a faster solid-phase gastric emptying (t_1/2 = 107.2 ± 0.8 min) relative to ADM (t_1/2 = 113.1 ± 2.7 min), likely due to improved texture and rehydration. Both jerky types exhibited progressive particle disintegration; by 180 min, large particles (>2.0 mm) decreased to 16.88% ± 2.63% in ADM and 20.04% ± 0.64% in VFDM (p > 0.05). Protein digestibility, measured by SDS-PAGE and the degree of hydrolysis (DH), was significantly higher in VFDM (38.5 ± 3.6%) than in ADM (34.0 ± 0.1%, p < 0.05), with VFDM demonstrating more rapid and extensive protein degradation across gastric and intestinal phases. These improvements may be attributed to the porous microstructure and reduced processing-induced protein cross-linking in VFDM, facilitating enhanced enzyme access. Overall, vacuum freeze-drying substantially improved yak jerky protein digestibility, offering the potential for the development of meat-based functional foods targeted at individuals with compromised gastrointestinal function. Full article

The delayed healing and infection risks associated with chronic wounds and burns pose significant clinical challenges. Traditional dressings provide basic coverage but lack the bioactive properties needed for tissue regeneration and antimicrobial protection. In this study, we developed zinc alginate hydrogel-coated traditional wound dressings (WD@AlgZn) and evaluated their physicochemical properties, antimicrobial performance, and in vivo healing efficacy. Scanning electron microscopy (SEM) revealed a uniform coating of the zinc alginate network on dressing fibers, while Fourier-transform infrared spectroscopy (FT-IR) confirmed the successful incorporation of zinc ions. Antimicrobial assays further demonstrated that WD@AlgZn reduced bacterial loads (CFU/mL counts) by several orders of magnitude for both Staphylococcus aureus and Escherichia coli compared to uncoated controls. An in vivo rat burn wound model exhibited accelerated wound closure when using WD@AlgZn dressings compared to conventional wound care approaches, achieving a 90.75% healing rate by day 21, significantly outperforming the silver sulfadiazine (52.32%), uncoated-dressing (46.58%), and spontaneous-healing (37.25%) groups. Histological analysis confirmed enhanced re-epithelialization, neovascularization, and reduced inflammation in WD@AlgZn-treated tissues. The findings suggest that WD@AlgZn offers a promising alternative for advanced wound management, combining structural robustness with bioactive properties to support efficient wound healing and infection control. These results provide valuable insights into the potential clinical applications of metal-ion cross-linked biopolymeric hydrogel dressings for next-generation wound care strategies. Full article

Polymeric scaffolds are promising in tissue engineering due to their structural similarity to extracellular matrix components. This study aimed to design freeze-dried hydrogels based on chitosan (CHT) and hyaluronic acid (HA). Chitosan-based gels were crosslinked with oxidized maltodextrin (MDo) before the freeze-drying step, resulting in spongy porous scaffolds. Based on the state-of-the-art, our hypothesis was that crosslinking would increase scaffold stiffness and delay the degradation of the CHT:HA resorbable scaffolds swelled in a hydrated physiological environment. The physicochemical and mechanical properties of crosslinked CHT- and CHT:HA-based scaffolds were analyzed. Hygroscopic and swelling behavior were assessed using dynamic vapor sorption analysis and batch studies. Degradation was evaluated under different conditions, including in phosphate-buffered saline (PBS), PBS with lysozyme, and lactic acid solutions, to investigate scaffold resistance against enzymatic and acidic degradation. The porosity of the spongy materials was characterized using scanning electron microscopy, while dynamic mechanical analysis provided information on the mechanical properties. Crosslinked scaffolds showed reduced swelling, slower degradation rates, and increased stiffness, confirming MDo as an effective crosslinking agent. Scaffolds loaded with ciprofloxacin (CFX) demonstrated their ability to deliver therapeutic agents, as the CFX loading capacity was promoted by CHT–CFX interactions. Microbiologic investigation confirmed the results. Finally, cytotoxicity tests displayed no toxicity. In conclusion, MDo-crosslinked CHT and CHT:HA scaffolds exhibit enhanced stability, functionality, and mechanical performance, making them promising for cartilage tissue engineering. Full article

Cleft palate is one of the most common congenital abnormalities and one of the main symptoms of Stickler syndrome. Secondary palate development is a complex multi-step process that involves raising the palatal frame from a vertical to a horizontal position. Lysyl oxidase-like 3 (LOXL3), a member of the lysyl oxidase family responsible for the crosslinking in collagen, is also one of the mutated genes detected in Stickler syndrome. Loss of Loxl3 causes delayed palatal shelf elevation, which in turn resulted in cleft palate. However, the precise mechanisms of palatal shelf delayed elevation remain unclear. In this study, we deeply investigated the mechanism of Loxl3 induced delayed elevation in palatal shelves. We found that Loxl3 deficiency caused reduced cell proliferation in both medial and posterior palatal mesenchyme through BrdU labeling and Western blot analysis (p < 0.05, p < 0.01), decreased migration of palatal mesenchymal cells through cell scratch assay (p < 0.05), and decreased expression of genes associated with proliferation through Western blot analysis (p < 0.05, p < 0.01) at E14. We found that the specific deletion of Loxl3 in the palatal mesenchyme resulted in delayed elevation but normal fusion of palatal shelves, also reduced cell proliferation and collagen fibers deposition in medial palatal mesenchyme through BrdU labeling and histological analysis (p < 0.05, p < 0.01). Thus, our data suggest that Loxl3 regulates cell proliferation and collagen fibers deposition in the palatal mesenchyme, thus controlling palatal shelf elevation. Full article

Nitric oxide (NO) is an endogenous signaling molecule that plays a critical role in wound healing. However, the gaseous nature, short half-life, and low stability of NO present challenges for its clinical application. To address these issues, this study introduces an innovative S-nitrosoglutathione (GSNO)-loaded asymmetric alginate (SA) hydrogel (GSNO-SA) as a novel solution for treating infected chronic wounds. The hydrogel is designed with a layer-by-layer melting-permeation crosslinking approach, forming a dense upper layer and a sparse lower layer structure, effectively promoting exudate management while delaying NO release. The results demonstrate that the GSNO-SA hydrogel extends NO release for up to 48 h, exhibits rapid exudate absorption (72.3 ± 1.5% equilibrium swelling after 5 min), significant antibacterial activity (over 90% antibacterial rate against E. coli and S. aureus), and anti-inflammatory effects (marked reduction in TNF-α expression), and promotes angiogenesis (90.00 ± 5.92% migration rate at 48 h). Additionally, animal studies show that the GSNO-SA hydrogel accelerates wound healing, achieving a 99.2 ± 0.1% closure rate at 14 days. Histological and immunohistochemical evaluations further confirm its ability to regulate inflammation (13.34-fold upregulation of CD163) and promote angiogenesis (3.02-fold upregulation of α-SMA). Theoretically, this asymmetric design provides a novel strategy for developing exudate-managing dressings by integrating controlled NO release with hierarchical pore structures. Full article

Background/Objectives: Periodontitis and diabetes mellitus share a well-established bidirectional relationship, where hyperglycemia exacerbates periodontal inflammation, and periodontal disease further impairs glycemic control. Within the diabetic periodontal microenvironment, an imbalance between pro-inflammatory (M1) and anti-inflammatory (M2) macrophages promotes chronic inflammation, oxidative stress, delayed healing, and alveolar bone resorption. Resveratrol (RSV), a polyphenol with antioxidant, anti-inflammatory, and pro-osteogenic properties, holds potential to restore macrophage balance. However, its clinical application is limited by poor bioavailability and instability. This study aimed to develop and evaluate a novel RSV delivery system to overcome these limitations and promote periodontal tissue regeneration under diabetic conditions. Methods: A drug delivery system comprising RSV-loaded solid lipid nanoparticles embedded within a cross-linked hyaluronic acid hydrogel (RSV@CLgel) was formulated. The system was tested under hyperglycemic and inflammatory conditions for its effects on macrophage polarization, cytokine expression, oxidative stress, mitochondrial function, and osteoblast differentiation. Results: RSV@CLgel effectively suppressed pro-inflammatory cytokines (TNF-α, IL-1β, IL-6) while upregulating anti-inflammatory markers (IL-10, TGF-β). It significantly reduced oxidative stress by decreasing ROS and lipid peroxidation levels and improved mitochondrial function and antioxidant enzyme activity. Furthermore, RSV@CLgel enhanced osteoblast differentiation, as evidenced by increased ALP activity, calcium nodule formation, and upregulation of osteogenic genes (COL-I, RUNX2, OCN, OPN). It also inhibited RANKL-induced osteoclastogenesis, contributing to alveolar bone preservation. Conclusions: The RSV@CLgel delivery system presents a promising multifunctional strategy for the management of diabetic periodontitis. By modulating immune responses, reducing oxidative stress, and promoting periodontal tissue regeneration, RSV@CLgel addresses key pathological aspects of diabetes-associated periodontal disease. Full article

To address the rapid crosslinking reaction and short stability duration of polyacrylamide gel under high salinity and temperature conditions, this paper proposes utilizing urea to delay the nucleophilic substitution crosslinking reaction among polyacrylamide, hydroquinone, and formaldehyde. Additionally, urea regulates the precipitation of calcium and magnesium ions, enabling the in situ preparation of an organic/inorganic composite gel consisting of crosslinked polyacrylamide and carbonate particles. With calcium and magnesium ion concentrations at 6817 mg/L and total salinity at 15 × 10⁴ mg/L, the gelation time can be controlled to range from 6.6 to 14.1 days at 95 °C and from 2.9 to 6.5 days at 120 °C. The resulting composite gel can remain stable for up to 155 days at 95 °C and 135 days at 120 °C. The delayed gelation facilitates longer-distance diffusion of the gelling agent into the formation, while the enhancements in gel strength and stability provide a solid foundation for improving the effectiveness of profile control and water shut-off in oilfields. The urea-controlling method is novel and effective in extending the high-temperature cross-linking reaction time of polyacrylamide. By converting calcium and magnesium ions into inorganic particles, it enables the in situ preparation of organic/inorganic composite gels, enhancing their strength and stability. Full article

Background/Objectives: Posaconazole is an antifungal agent from triazoles with variable bioavailability. To avoid its irregular absorption caused by gastric conditions and ensure more repeatable pharmacokinetic enabling the maximization of its absorption regardless of food intake without the need to administer multiple doses, can be provided by the technology of enteric drug preparations. The cross-linking of polysaccharide polymers with divalent and trivalent cations enables multi-unit formulations to be obtained that prevent drug absorption in the stomach. Microcapsules, as an example of multi-unit drug dosage forms, provide more predictable gastric emptying, depending on nutritional status, and spread extensively throughout the gastrointestinal tract. Methods: Therefore, the utilization of zinc acetate for the cross-linking of the alginate and pectin mixture was evaluated. The obtained formulations were evaluated for the impact of cross-linking process and pectin’s presence on their pharmaceutical, mucoadhesive, physicochemical and antifungal properties. Results: It was shown that cross-linked microcapsules by zinc acetate provided delayed posaconazole release. Additionally, the cross-linking process with Zn²⁺ ions significantly enhanced antifungal activity against the analyzed Candida strains. It was observed that pectin content in the formulation enhanced the swelling ability in an intestinal condition and increased the mucoadhesive properties of drug-loaded formulations to the intestinal mucosa. Full article

The nonunion and delayed union of bones are common challenges in orthopedic surgery, even when bone alignment is correct and sufficient mechanical stability is provided. To address this, artificial bone grafts are often applied to fracture gaps or defect sites to promote osteogenesis and enhance bone healing. In this study, we developed an alginate-based hydrogel incorporating gold nanoparticles (AuNPs) to enhance cell proliferation and facilitate bone healing through a photothermal effect induced by near-infrared (NIR) laser irradiation. The temperature was controlled by adjusting the AuNP content. The hydrogel’s properties were characterized and cell viability was assessed. Our results indicate that while the incorporation of AuNPs slightly disrupted the hydrogel’s cross-linking network at low concentrations, cell viability remained unaffected across both low and high AuNP contents. These findings suggest that this photothermal hydrogel holds great promise for orthopedic applications to improve bone healing. Full article

Periodontitis is a chronic inflammatory condition of the periodontium, which often leads to tooth loss. Recently, statins have emerged as potent anti-inflammatory agents with pleiotropic effects that can potentially outperform conventional periodontal treatments. However, the clinical application of statins is limited by the lack of suitable drug carriers that fit the periodontal region and provide a controlled local drug release. In this study, we address the critical gap in localized periodontal drug delivery and introduce an ultrasound-assisted technique to encapsulate atorvastatin within alginate microparticles (10–400 µm in diameter)—a simple, scalable, and biocompatible solution. While ultrasound is widely used in polymer synthesis, its application in alginate polymerization remains underexplored. To mimic physiological conditions, particles were incubated in artificial saliva at 37 °C, with drug release being analyzed via high-performance liquid chromatography. A methylcellulose-based hydrogel served as a conventional reference product. Results revealed that alginate particles exhibited at least a 10-fold increase in mean dissolution time compared to the methylcellulose gel, indicating superior stability. Increasing atorvastatin concentration extended the time interval needed for 50% of the drug to be released (t_50%) from 1 h to 11 h, maintaining the overall drug diffusion level for several days. Further analysis showed that covalent cross-linking of alginate with divinyl sulfone significantly delayed the initial drug release by 3 h (p < 0.05) due to the additional molecular stabilization. These findings underscore the utility of ultrasonic atomization for the processing of alginate-based formulations. Given the ease of production, biocompatibility, and small size, successfully fabricated alginate particles represent a promising carrier for delivery of statins or other related drugs in clinical dentistry. Full article

Background: O⁶-Methylguanine-DNA methyltransferase (MGMT) is a unique antimutagenic DNA repair protein that plays a crucial role in conferring resistance to various alkylating agents in brain tumor therapy. In this study, we exploited the susceptibility of the active site Cys145 of MGMT for thiolation and nitrosylation, both of which inactivate the enzyme. Methods: We designed a redox perturbing glutathione mimetic, a platinated homoglutathione disulfide (hGTX) by adding small amounts of cisplatin (1000:10) and used a nitric oxide-donor spermine NONOate. N6022, a potent inhibitor of S-nitrosoglutathione reductase was used to extend the retention of nitrosylated MGMT in tumor cell culture and subcutaneous xenografts. Results: Both hGTX and spermine NONOate inhibited MGMT activity in HT29, SF188, T98G, and other brain tumor cells. There was a robust increase in the alkylation-induced DNA interstrand cross-linking, G2/M cell cycle arrest, cytotoxicity, and the levels of apoptotic markers when either of the agents was used with alkylating agents. In the nude mice bearing T98G and HT29-luc2 xenografts, combinations of hGTX and spermine NONOate with alkylating agents produced a marked reduction in MGMT protein and tumor growth delay and regressions. N6022 treatment increased the presence of nitrosylated MGMT for a longer time, thereby extending the DNA-repair deficient state both in cell culture and preclinical settings. Conclusions: Our findings highlight the options for redox-driven therapeutic strategies for MGMT and suggest that oxidative and/or nitrosative inactivation of DNA repair in combination with alkylating agents could be exploited. Full article