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Abstract Focused ion beam (FIB) is an effective tool for precise nanoscale fabrication. It has recently been employed to tailor defect engineering in functional nanomaterials such as two-dimensional transition metal dichalcogenides (TMDCs), providing desirable properties in TMDC-based optoelectronic devices. However, the damage caused by the FIB irradiation and milling process to these delicate, atomically thin materials, especially in extended areas beyond the FIB target, has not yet been fully characterised. Understanding the correlation between lateral ion beam effects and optical properties of 2D TMDCs is crucial in designing and fabricating high-performance optoelectronic devices. In this work, we investigate lateral damage in large-area monolayer WS2 caused by the gallium focused ion beam milling process. Three distinct zones away from the milling location are identified and characterised via steady-state photoluminescence (PL) and Raman spectroscopy. The emission in these three zones have different wavelengths and decay lifetimes. An unexpected bright ring-shaped emission around the milled location has also been revealed by time-resolved PL spectroscopy with high spatial resolution. Our findings open up new avenues for tailoring the optical properties of TMDCs by charge and defect engineering via focused ion beam lithography. Furthermore, our study provides evidence that while some localised damage is inevitable, distant destruction can be eliminated by reducing the ion beam current. It paves the way for the use of FIB to create nanostructures in 2D TMDCs, as well as the design and realisation of optoelectrical devices on a wafer scale.

Significant progress has been made in two-dimensional material-based sensing devices over the past decade. Organic vapor sensors, particularly those using graphene and transition metal dichalcogenides as key components, have demonstrated excellent sensitivity. These sensors are highly active because all the atoms in the ultra-thin layers are exposed to volatile compounds. However, their selectivity needs improvement. We propose a novel gas-sensing device that addresses this challenge. It consists of two side-by-side sensors fabricated from the same active material, few-layer molybdenum disulfide (MoS₂), for detecting volatile organic compounds like alcohol, acetone, and toluene. To create a dual-channel sensor, we introduce a simple step into the conventional 2D material sensor fabrication process. This step involves treating one-half of the few-layer MoS₂ using ultraviolet–ozone (UV-O3) treatment. The responses of pristine few-layer MoS₂ sensors to 3000 ppm of ethanol, acetone, and toluene gases are 18%, 3.5%, and 49%, respectively. The UV-O3-treated few-layer MoS₂-based sensors show responses of 13.4%, 3.1%, and 6.7%, respectively. This dual-channel sensing device demonstrates a 7-fold improvement in selectivity for toluene gas against ethanol and acetone. Our work sheds light on understanding surface processes and interaction mechanisms at the interface between transition metal dichalcogenides and volatile organic compounds, leading to enhanced sensitivity and selectivity.

Ultraviolet-ozone (UV-O3) treatment is a simple but effective technique for surface cleaning, surface sterilization, doping, and oxidation, and is applicable to a wide range of materials. In this study, we investigated how UV-O3 treatment affects the optical and electrical properties of molybdenum disulfide (MoS2), with and without the presence of a dielectric substrate. We performed detailed photoluminescence (PL) measurements on 1–7 layers of MoS2 with up to 8 min of UV-O3 exposure. Density functional theory (DFT) calculations were carried out to provide insight into oxygen-MoS2 interaction mechanisms. Our results showed that the influence of UV-O3 treatment on PL depends on whether the substrate is present, as well as the number of layers. Additionally, 4 min of UV-O3 treatment was found to be optimal to produce p-type MoS2, while maintaining above 80% of the PL intensity and the emission wavelength, compared to pristine flakes (intrinsically n-type). UV-O3 treatment for more than 6 min not only caused a reduction in the electron density but also deteriorated the hole-dominated transport. It is revealed that the substrate plays a critical role in the manipulation of the electrical and optical properties of MoS2, which should be considered in future device fabrication and applications.

Abstract Introduction The objective of this study is to investigate the shear bonding strength of a glycoalkaloid, also a novel matrix metalloproteinase enzyme known as α-tomatine, on two different surfaces of dentin (sound & caries-affected) and its efficacy against cariogenic microorganisms using in vitro and in silico methods. Methods The effect of a-tomatine at different concentrations (0.75 / 1 / 1.5 µM) on shear bonding strength in caries-affected and sound dentin was also investigated (n = 10; each per subgroup). The analysis of shear bonding and failure tests was conducted after a 24-hour storage period. Fracture surfaces were examined under a scanning electron microscope. A stock solution 3 mM of a-tomatine was prepared for antimicrobial evaluation. Antimicrobial activities of the agents against Streptococcus mutans ATCC 25175, Lactobacillus casei ATCC 4646, and Candida albicans ATCC 10231 standard strains were investigated by microdilution method. In addition, through the method of molecular docking and dynamic analysis, the affinity of a-tomatine for certain enzymes of these microorganisms was examined. Results The pretreatment agent and dentin type significantly influenced shear bonding strength values (p

Aim:Sustained release of inflammatory mediators, excessive inflammatory response and impaired intestinal epithelial restitution are well-known mechanisms in the pathogenesis of necrotizing enterocolitis. This study focused on the effect of resveratrol on these pathways.Materials and Methods:In this study, the rat crypt intestinal cell line (IEC-6) culture, an application of lipopolysaccharide or a cytokine mixture and a scratch migration assay model were used. Nitric oxide synthase-2 (iNOS) and cyclooxygenase-2 (COX-2), focal adhesion kinase (FAK) and its phosphorylated form (pFAK) levels were assessed.Results:IEC-6 cells covered 88% of the denuded area in the control, 54% in LPS, and 35% in cytomix groups at the 24th hour. The treatment with resveratrol at doses of 0.5, 1 and 5 μM/L before LPS resulted in the repair of 84%, 87% and 76% of the denuded areas, respectively. Likewise, with cytomix, it was 86%, 82%, and 78%. Resveratrol at a dose of 5 μM/L prevented an increase in iNOS levels. All three doses of resveratrol were effective in preventing increases in COX levels. FAK or pFAK expressions remained unchanged in all groups.Conclusion:Resveratrol, being known for its antioxidant features, suppresses excessive inflammatory response and helps preservation of mucosal integrity by conservation of epithelial restitution.

The aim of this study was to compare the topographical, chemical and osseointegration characteristics of sandblasting and acid-etching (SLA) surfaces and dental implants treated by boron compounds. Titanium (Ti) disks (n = 20) were modified using boron (B) and boric acid (H3BO3) and then compared with the conventional SLA surface via surface topographic characterizations. Dental implants (3.5 mm in diameter and 8 mm in length) with the experimental surfaces (n = 96) were inserted into the tibias of six sheep, which were left to heal for 3 and 7 weeks. Histologic, histomorphometric (bone–implant contact (BIC%)) and mechanical tests (removal torque value (RTV)) were performed. The boron-coated surface (BC group) was smoother (Rz: 4.51 μm ± 0.13) than the SLA (5.86 μm ± 0.80) and the SLA-B (5.75 μm ± 0.64) groups (p = 0.033). After 3 weeks, the highest mean RTV was found in the SLA group (37 N/cm ± 2.87), and the difference compared with the BC group (30 N/cm ± 2.60) was statistically significant (p = 0.004). After 7 weeks, the mean RTV was >80 N/cm in all groups; the highest was measured in the H3BO3-treated (BS) group (89 N/cm ± 1.53) (p < 0.0001). No statistically significant differences were found in the BIC%s during both healing periods between the groups. H3BO3 seems to be a promising medium for dental implant osseointegration.