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Purpose: To evaluate the bond strength to dentin produced by experimental adhesives formulated with an elastomeric methacrylate monomer (EMM) and an alternative initiator system based on a Thioxanthone derivative (QTX). Materials and Methods: A self-etching primer was used. For the bonding resin, a model adhesive (G1) was formulated containing bis-GMA/TEG-DMA/HEMA (co-monomeric blend) + CQ/EDAB (initiator system). The other groups were formulated by adding to this formulation: EMM only (G2), QTX (G3), or EMM and QTX (G4). Clearfil SE Bond was used as the commercial control group. Fifty bovine teeth (n = 5) were restored with each one of the five adhesives. After restorative procedures, half of the specimens were stored in distilled water at 37°C for 24 h. The other half was fixed on a metal stub and subjected to 200,000 mechanical (50 N loading at 2 Hz frequency) and 1000 thermal cycles (5°C and 55°C). Afterwards, specimens were serially sectioned into beams and tested in tension until fracture. Bond strengths were statistically analyzed by two-way ANOVA and Tukey's test (a = 5%). Results: After 24 h, significantly higher µTBS was observed for the formulation containing EMM and QTX (G4) when compared to Clearfil SE Bond (p < 0.05). No significant differences in µTBS were detected among the experimental groups after 24 h (p>0.05). After thermomechanical cycling, no significant differences were observed among groups. Conclusion: The addition of EMM and QTX can be considered as possible alternative in dental adhesive formulations. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate through a systematic review and meta-analysis whether the immediate and long-term bonding performance of universal adhesives would be improved by prior acid etching. Materials and Methods: Two reviewers performed a literature search up to April 2018 in eight databases: PubMed, Web of Science, Cochrane Library, SciELO, Scopus, LILACS, IBECS, and BBO. Only studies that evaluated the dentin or enamel bond strength of universal adhesives using a self-etch or etch-and-rinse strategy were included. Analyses were carried out using RevMan 5.3.5 (The Nordic Cochrane Centre, The Cochrane Collaboration, Copenhagen, Denmark). A global analysis comparing self-etch or etch-and-rinse strategies and the influence of aging on bonding performance was performed with random-effects models at a significance level of p < 0.05. Results: A total of 59 in vitro studies were included in the meta-analysis. The enamel bond strength of universal adhesives was improved by the etch-and-rinse approach (p < 0.05). In dentin, this effect was observed for ultramild and intermediately strong universal adhesives (p < 0.05). Irrespective of the strategy employed, intermediately strong adhesives showed a decrease in bond strength after all types of aging. This effect was also observed for ultra- mild universal adhesives used in the etch-and-rinse approach (p < 0.05). Mild universal adhesives showed bond strength stability in both strategies (p > 0.05). Conclusions: The in vitro evidence suggests that bonding performance of mild universal adhesives can be improved by using the selective enamel-etch strategy. Mild universal adhesives seem to be the more stable materials, in both etch-and-rinse or self-etch strategies. [ABSTRACT FROM AUTHOR]

Keywords: Nanocellulose; biological pretreatment; cellulase; eucalyptus; ; ; ; EN Nanocellulose biological pretreatment cellulase eucalyptus ZH 9363 9372 10 11/21/22 20221220 NES 221220 Introduction The global demand for cellulose nanofibers (CNF) and other cellulosic nanomaterials overcame 10,000 tons in 2018 and this demand is expected to increase to more than 70,000 tons by 2030 (Santmarti, Tammelin, and Lee [33]). In the present study, CNF were extracted from a bleached hardwood pulp using enzymatic hydrolysis as a pretreatment for subsequent mechanical fibrillation. In a comparison between unhydrolyzed pulps, that bleached pulp presented a higher crystallinity index than the unbleached one, which indicates that the bleaching sequence applied by our supplier partly removed some amorphous components, like hemicelluloses and lignin (De Campos et al. [10]). In general, compared to the unhydrolyzed CNF, it is clear that the CNF extracted from the unbleached pulp presented smaller decreases in diameter (around 75%) than those from bleached pulp, which showed decreases of almost 65%. [Extracted from the article]

Flexible and wearable electrochemical biosensors are considered a non-invasive tool for monitoring biological substances, thus attracting attention due to the simple assembly, fast response, ultra-sensitivity, and low cost. Among the substances detected by electrochemical methods, ascorbic acid (AA) stands out, as its presence in the body promotes adequate physiological functions of the immune, central nervous, and circulatory systems, thus preventing and treating various diseases. Herein, this work focuses on the use of nanostructured NdNiO3 compounds in an alternative flexible biosensor for AA detection by electrochemical sensing. Here, 1D nanostructures of NdNiO3 were obtained by wet pore filling of a mesoporous aluminum oxide template. To the best of our knowledge, no electrochemical biosensors using NdNiO3 nanotubes supported onto GO flexible electrodes have been reported for AA or other bioanalyte detection. Next, an electrochemical biosensor for AA was built using a laser-induced graphene (GO) electrode and two different NdNiO3 (NNO) nanotubes, one with an external diameter of 20 nm (NNO20) and the other with 100 nm (NNO100). The size effect and Ni3+/Ni2+ ratio influence on the sensing properties can be verified through electrochemical characterization. The GO/NNO20 and GO/NNO100 biosensors presented a detection range of 30 to 1100 μmol L-1, but the minimum detectable limit (3.8 μmol L-1) and sensitivity (0.031 μA μM-1 cm-2) are significantly better for the GO/NNO100 device. These outstanding results make both devices competitive with other AA devices listed in the literature. We also simulated the biosensors' real application and verified that these biosensors could detect AA in synthetic sweat and under application of mechanical deformations. Thus, the GO/NNO biosensors showed a promising alternative to the development of real-time monitoring, POC devices, and flexible wearable electrochemical devices to use in AA detection. Future works should address the potential to detect other bioanalytes. [ABSTRACT FROM AUTHOR]