One-pot approach for synthesis of multi-layered nanosheets of N-dopped graphene derived from chitosan for reinforcing cement mortar.

The synthesis of graphene via traditional methods has several drawbacks, such as the release of poisonous gases, Most of these techniques are time-consuming and tedious, besides the absence of control over the structural composition of graphene during synthesis. In this study, a facile approach for the synthesis of graphene densely doped with nitrogen (N-dopped graphene (NG)) from novel precursor chitosan throughout the direct solvothermal treatment of chitosan under mild circumstances at 250 °C and 270 °C. Cetyltrimethylammonium bromide (CTAB) and ammonia are utilized as structural directing agents. FTIR, XRD, CHNS/O elemental analysis, XPS, and Raman spectroscopy are utilized to elucidate the chemical composition and purity of N-dopped graphene. The surface morphology of NG is studied by using SEM, HR-TEM, and selected area electron diffraction (SAED). The results approved that, the one-pot, single-step approach is a simple and cost-effective technique for producing a high throughput of NG, of charming microstructure features, including good graphitization, low oxidation state, good exfoliation level, and very extended lateral dimension sheets. Profound visions on the growing mechanism have been proposed. The incorporation effect of NG to cement mortar is also studied. Two percentages of NG 0.05 wt% and, 0.10 wt% from the total cement mass were utilized. A microstructural investigation of incorporated NG on cement mortar is studied by conducting AFM, and SEM. Furthermore, workability and mechanical characterizations including, compressive strength, and flexural strength are investigated. Also, the dynamic mechanical parameters including storage modulus and loss factor are studied. It is noticed that the workability decreased from 14.8 % to 7.8 % with the addition of 0.05 wt% and 0.1 wt% NG respectively. However, the maximum increments of the compressive strength were 35 % for the mortar containing 0.1 wt% NG and flexural strength increased three times than the unmodified one. Also, the cement mortar containing 0.1 wt% NG has a storage modulus of 12 MPa compared to unmodified 1 MPa and has the lowest loss factor (damping coefficient). These results verified that incorporating NG nanosheets in cement has a positive effect on reinforcing cement mortar.

Effect of cervical margin relocation on marginal adaptation and microleakage of indirect ceramic restorations.

PURPOSE: This study evaluated the effect of cervical margin relocation (CMR) with two different materials and contamination with hemostatic agents on the margin adaptation and microleakage of ceramic restorations. MATERIALS AND METHODS: Mesial-occlusal-distal cavities were prepared in 60 human first molars and distributed to 3 groups (n = 20) according to the margin relocation procedure. The groups were: group F; flowable composite applied in two 2 mm increments, group B; bulk-fill flowable composite applied as a bulk increment of 4 mm thickness and group C (control); no CMR was done. Each group was subdivided into two subgroups (subgroup N; no hemostatic agent applied and subgroup H; hemostatic agent was applied). In all groups, ceramic inlays were prepared and cemented. The samples were subjected to thermocycling (10,000 cycles). The adaptation of the cervical margin was evaluated with scanning electron microscopy (200×). Samples were then assessed for microleakage analysis with the dye penetration method. Marginal adaptation data were normally distributed and analyzed using two-way ANOVA followed by Tukey's post hoc test. Ordinal microleakage score data were analyzed using cumulative link models followed by the analysis of deviance using Wald chi-square tests. RESULTS: Both CMR and contamination with a hemostatic agent had significant effects on the margin adaptation of the cervical margin. Group C showed the highest adaptation with no significant difference from group F. The lowest adaptation was revealed in group B with a significant difference from group C. Subgroup N (in all groups) showed a statistically higher adaptation than subgroup H. Regarding microleakage assessment, CMR had no significant effect but hemostatic agent application showed a significantly higher microleakage score for all groups. CONCLUSIONS: Both the CMR procedure and contamination with AlCl3 hemostatic agent had a negative effect on marginal adaptation. For microleakage assessment, only contamination with hemostatic agent negatively affected the microleakage with no effect on the margin relocation procedure.

Clinical impact of LncRNA XIST and LncRNA NEAT1 for diagnosis of high-risk group breast cancer patients.

Long noncoding RNAs (lncRNAs) are evolving as contributing biomarkers for many diseases. Among these lncRNAs, X inactive-specific transcript (XIST), and nuclear paraspeckle assembly transcript 1 (NEAT1) were studied as undesirable upregulated nucleic acid markers for unfavorable prognosis of cancer. The authors aimed to investigate their role as diagnostic markers for breast cancer (BC) patients with high-risk factors. Serum samples were obtained from BC patients (n = 121), patients with benign breast lesions (n = 35), and healthy volunteers (n = 22). Assessment of lncRNA XIST, and lncRNA NEAT1 expression was performed using real time PCR. Expression levels of the investigated lncRNAs were significantly higher in BC patients as compared to the other groups. Both lncRNAs were significantly correlated with BC laterality, lymph node involvement, and clinical stages. LncRNA NEAT1 reported a significant aberrant expression with pathological types, histological grading and, hormonal status. The sensitivity of lncRNA NEAT1 was superior for detection of BC with high risk-factors as compared to lncRNA XIST. In conclusion, the detection of lncRNAs in body fluids has demonstrated a significant importance for detecting BC patients with high-risk factors, and was related to hormonal receptors, thus may be used for determining the direction of treatment strategy.