Multilayered bacterial cellulose (MBC)/reduced graphene oxide (rGO) composite films were fabricated using dyeing method. First, MBC films were constructed by the static culturing of kombucha SCOBY bacterial cellulose in a rectangular plastic mold for 15 days. The MBC formed on the air-liquid interface was collected and employed as the matrix for the preparation of MBC/rGO composite films using dyeing method. As found, the color strength increased with an increase in dyeing cycle due to MBC and GO (rGO precursor) affinity. However, the surface hydrophilicity was found in the opposite direction due to the restacking of hydrophobic rGO nanosheets onto MBC surface after reduction step. SEM images confirmed that MBC/rGO composite films obtained by the dyeing method exhibited the intact multilayer structure. The electrochemical behavior of free-standing and binder-free MBC/rGO electrodes was evaluated. It was found that MBC-1 exhibited the highest specific capacitance value of 192.23 F/g at the current density of 1 A/g (calculated from GCD plots) due to good diffusion of electrolyte arising from surface wettability with current density performance of 66 %. An increase in dyeing cycle (MBC-2, MBC-3, and MBC-4) led to a gradual decrease in the corresponding specific capacitance value due to a gradual increase in the electrolyte resistance derived from an increasing surface hydrophobicity of the composite films. Finally, in all cases, long-term cycle stability of more than 90 % up to 10000 cycles was achievable.

In this study, Mn-doped ZnO composite carbon nanofibers (Mn-ZnO/CNFs) were prepared via a simple blending and electrospinning (ES) method, followed by a thermal treatment. These fibers were used to investigate the photocatalytic degradation of an organic dye under UV and visible light irradiation. The results showed that Mn-ZnO/CNFs were successfully prepared under the same conditions used for CNFs preparation conditions, which induced a morphological change from a smooth to a rough surface compared to the CNFs. Energy dispersive X-ray (EDX), x-ray diffraction (XRD), and x-ray photoelectron spectroscopy (XPS) analyses confirmed the formation of Mn-doped ZnO on the CNFs' surface. Furthermore, the addition of the catalyst significantly increased in the specific surface area, and a N₂ adsorption-desorption isotherm analysis revealed that all samples had mesoporous characteristics with a type IV isotherm index. The photocatalytic activity of the Mn-ZnO/CNFs carbonized at 650 ℃ using methylene blue (MB) dye as a model pollutant was investigated. All prepared samples effectively removed the MB with a degradation rate of 70-90%. The kinetic reaction rate was described using the simplified Langmuir-Hinshelwood equation. Overall, the CNFs and composites nanofibers developed through moderate thermal treatment processes possessed a high specific surface area and oxygen vacancy, enabling their potential use as adsorbents and as a catalyst support for reactions at room-to-elevated temperatures, as well as photocatalysts for the removal of organic contaminants.

ZnO nanoparticles were successfully synthesized by using zinc dust waste derived from hot-dip galvanizing process as a starting materials via simple hydrothermal method. The zinc dust powder was dissolved in nitric acid, adjusted pH with NaOH and hydrothermally treated at 120-170°C in an oven. The resultant products were characterized for phase, surface area and morphology by X-ray diffraction (XRD), Brunauer-Emmet-Taller (BET) and Scanning electron microscopy (SEM), respectively. Moreover, the photocatalytic activity was investigated by a photodegradation of methylene blue solution under black light irradiation. It was shown that crystallinity of pure ZnO phase, was influenced by solution and hydrothermal treatment temperature. The experimental results exhibited that the crystallinity of ZnO significantly affected its photocatalytic activity. The highest photocatlytic activity was obtained from powders with average crystallite size of 51 nm and surface area of 13.4 m²/g prepared under pH12 and hydrothermally treated at 170°C for 6 h. Moreover, the synthesized ZnO powders performed a good antibacterial activity evaluated using a colony count method with Escherichia coli under the dark condition.

This in vitro study investigated the fracture resistance of three ceramic-reinforced polymer (CRP) crowns—Cerasmart^® 270 (CE; milled), VarseoSmile Crown Plus^® (VS; 3D-printed) and the newly developed Hassawat-01 (HS; 3D-printed)—luted with cements of different elastic moduli. The principal hypothesis was that neither the CRP type nor the modulus of cement would significantly affect fracture resistance. Ninety-nine mandibular first molar resin dies were restored with 1 mm thick CE, VS, or HS crowns (n = 33 each) and luted with Maxcem Elite^®, RelyX Unicem^®, or Ketac Cem^® (n = 11 per subgroup). Occlusal cement morphology was evaluated using Micro-CT. Fracture resistance was measured using a universal testing machine. Crowns luted with Maxcem or RelyX withstood forces >2000 N without visible failure. Ketac-luted crowns showed reduced fracture resistance. CE-Ketac fractured in 4 of 11 specimens. VS-Ketac exhibited cracks or complete fractures (1795.2 ± 156.7 N), whereas HS-Ketac showed only superficial cracking (1732.6 ± 127.3 N). CRP crowns luted with lower-modulus resin cements demonstrated superior fracture resistance compared with those luted with glass-ionomer. VS exhibited both cracking and occasional complete fractures, whereas HS exhibited only surface cracking. All materials withstood loads greater than typical masticatory forces, supporting HS as a promising alternative within the CRP.

A novel alumina-filled ceramic-reinforced polymer (CRP) crown (Hassawat-01; HS) was developed. This study evaluated the effect of luting cement on the marginal and internal adaptation of HS and compared its performance with a commercial DLP-printed CRP (VarseoSmile Crown Plus^®; VS) and a milled resin nanoceramic (Cerasmart^® 270; CE). Ninety-nine crowns (n = 33/material) were fabricated with a 50 µm cement space and luted using Maxcem Elite^®, RelyX Unicem^®, or Ketac Cem^® (n = 11/subgroup). Adaptation was assessed without and with cementation using micro-computed tomography at 160 measurement points per crown. Without cementation, HS demonstrated the most favorable internal adaptation, whereas VS showed the best marginal adaptation. Following cementation, gap dimensions increased in all groups. Despite its superior non-cementation fit, HS exhibited the greatest increase in marginal and internal discrepancies, suggesting increased hydraulic resistance during seating. Among the evaluated cement–crown combinations, VS luted with RelyX Unicem^® showed the most favorable post-cementation adaptation. Post-cementation analysis was limited to HS and VS because the radiopacity of CE prevented reliable cement interface segmentation. These findings indicate that adaptation is influenced by both crown geometry and cement properties, and that highly adapted intaglio surfaces may require careful cement selection to optimize clinical fit.

Cockle shells, which are discarded as waste by the food industry, have been used in medical fields. This study aimed to manufacture a newly developed cockle shell-derived bioceramic sealer (NDBS) and evaluate its physical and biological properties. Cockle shell-derived tricalcium silicate (C-C₃S) was synthesized via the solid-state reaction technique and analysed for chemical composition and particle size. NDBS was prepared by mixing C-C₃S with specific additives. The chemical composition and surface morphology of fully set sealers were assessed using X-ray diffraction, Fourier-transform infrared spectroscopy, and scanning electron microscopy. Physical properties were tested according to International Organization for Standardization 6876 standards. For biological testing, both sealers were extracted and diluted for cytotoxicity and proliferation assays on human periodontal ligament cells using the MTT assay. Reverse transcription-quantitative polymerase chain reaction was performed to evaluate changes in proinflammatory (interleukin-6, interleukin-8, tumour necrosis factor-alpha-α) and mineralization (alkaline phosphatase) gene expression. C-C₃S was found to contain 55% tricalcium silicate with a particle size of 5.32 microns. Both fully set sealers contained tricalcium silicate and calcium silicate hydrate. They demonstrated acceptable flowability, setting time, film thickness, and radiopacity, although their solubility exceeded International Organization for Standardization limits. Both sealers maintained a pH above 7, with no significant difference in calcium release after 2 weeks. The MTT assay indicated improved cell viability with increasing dilution. Reverse transcription-quantitative polymerase chain reaction showed that both sealers showed a tendency to reduce proinflammatory gene expression. Both sealers showed a tendency to upregulate alkaline phosphatase gene expression. Within the limitations of this study, it was shown that cockle shells can be used to manufacture NDBS, which demonstrated physical and biological properties comparable to those of iRoot SP. This study highlights the potential of NDBS to be further developed as a root canal sealer.