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• Enamel Conditioner and ZON etchant etched enamel as affective as phosphoric acid. • EC, ZON and phosphoric acid resulted in comparable bond strength to enamel. • Multi Etchant dissolved hydroxyapatite rods least, as revealed by TEM. Enamel bond durability of three new alternative etchants combined with three representative adhesives was determined. The 'immediate' and 'aged' micro-tensile bond strength (μTBS) of the 3-step etch&rinse adhesive OptiBond FL ('O-FL', Kerr), 2-step self-etch (SE) adhesive Clearfil SE Bond 2 ('C-SE2', Kuraray Noritake) and universal adhesive Adhese Universal ('ADU', Ivoclar Vivadent) were measured when bonded to enamel following either a proprietary organic acid-containing Enamel Conditioner ('EC', Shofu), a phosphoric-acid monomer-containing Multi Etchant ('ME', Yamakin: 10-methacryloyloxy tetraethylene glycol dihydrogenphosphate or MTEGP), or a metal salt-based ZON etchant ('ZON', Ivoclar Vivadent: ZrO(NO 3) 2). All alternative etchants were used in replacement of phosphoric acid, the latter (K-Etchant, Kuraray Noritake) also used with O-FL and ADU, in addition to C-SE2 that was solely used in SE mode (controls). The enamel-etching patterns and de-bonded fracture surfaces were examined by SEM, while the interfaces with enamel were ultra-morphologically characterized by TEM. No statistically significant difference in immediate and aged μTBS, obtained by combining the three alternative etchants with the three adhesives, was recorded as compared with the respective controls, except for ME combined with O-FL. Upon aging, significant reduction in μTBS was recorded for the ME/C-SE2 and ME/ADU combinations. The percentage of adhesive failures increased with aging. SEM revealed similar etching patterns produced by EC and ZON as by classic phosphoric-acid etching, for which also numerous micro-resin tags at the adhesive-enamel interface were disclosed. Durable bonding to enamel was generally obtained for all etchant/adhesive combinations with the exception of the ME/O-FL combination. [ABSTRACT FROM AUTHOR]

Objective: To investigate, by means of microtensile bond strength test (μTBS), nanoleakage expression analysis (NL), gelatin zymography and in situ zymography, the effects of an experimental metal salt-based zirconium oxynitrate etchant [ZrO(NO 3 ) 2 ,] - ZON with two simplified adhesives on long-term bond strength and endogenous enzymatic activities., Methods: Middle/deep coronal dentin surfaces (N = 32) were conditioned either with a traditional 37 % H 3 PO 4 etchant (TE) or with ZON. Further, a single-component etch-and-rinse adhesive (EF) or a universal adhesive (AU) were applied and μTBS and NL tests were performed. Additional freshly extracted teeth were processed for gelatin zymography and in situ zymography evaluation. The tests were performed at baseline and (T0) and after 1-year-aging (T12). Bond strength and in situ zymography results were analyzed using analysis of variance (ANOVA) (three-way and one-way, respectively), while Chi-squared test was used for the NL results. Statistical significance was preset at α = 0.05., Results: All the investigated factors (adhesive system, dentin conditioner and aging) significantly influenced μTBS, with the AU and ZON performing better compared to EF and TE, respectively, and with lower bond strength values after aging (p < 0.05). Incremented silver nitrate deposits were observed at the adhesive interfaces after aging, especially for the TE groups (p < 0.05). Further, the experimental groups treated with ZON had significantly lower levels of enzymatic activity compared to TE, as shown by gelatin and in situ zymography (p < 0.05)., Conclusions: The experimental etchant demonstrated promising results in hybrid-layer preservation over time when used with simplified bonding systems, and could therefore be recommended in the clinical practice., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Lithium sulfur battery is deemed to one of the most hopefully useable and cost-effective options beyond traditional lithium ion batteries. Nevertheless, the intermediates shuttle effect and the instability of the lithium metal anode are still the significance of barriers to the actual application of lithium sulfur battery. In this work, zirconium oxynitrate (ZrO(NO 3) 2), which delivers good thermal stability and little hygroscopicity, is proposed as a dual functional electrolyte additive to ameliorate the electrochemical performance of lithium sulfur batteries. For one thing, the ZrO2+ cations possess a strong affinity to sulfur, which can catalyze the conversion of dissolved polysulfides to S 8. For another, ZrO(NO 3) 2 is negatively charged in the ether electrolyte because of the coordination ability of ZrO2+. It displays a strong repulsion to polysulfides which would effectively trap the dissolved polysulfides and prevent the polysulfides from diffusing into the electrolyte phase. Additionally, NO 3 − anions can be reduced and form a stable passivation film on Li-metal anode, which is beneficial to decrease the reacting activity of Li-metal anode upon polysulfides and stabilizing the surface topography of the Li-metal anode. Ultimately, the ZrO(NO 3) 2 electrolyte additive observably enhances the discharge capacity and cycle stability of Lithium sulfur battery. The dissolution of polysulfides results in low columbic efficiency and short cycle life of Li-S batteries, as polysulfides can shuttle to the anode area and easily react with the lithium anode. Since the strong coordination ability, ZrO(NO 3) 2 electrolyte additive can catalyze the conversion of lithium polysulfides to elemental S 8 , preventing the dissolution and diffusion of polysulfides. Addition, NO3- anions can stabilize the Li anode. Then, it effectively inhibits the shuttle effect and observably improve the discharge capacity and cycle stability of Li-S batteries. Image 1 • Negatively charged ZrO(NO 3) 2 electrolyte has a repulsion to lithium polysulfides. • ZrO(NO 3) 2 additive can catalyze the conversion of dissolved polysulfides to S 8. • Low hygroscopicity ZrO(NO 3) 2 can protect Li-metal anode. [ABSTRACT FROM AUTHOR]

A simple and convenient protocol has been developed for ipso‐nitration of arylboronic acid catalysed by molecular iodine at room temperature, using zirconium oxynitrate as the nitrating species. The protocol is applicable to electronically diverse aryl‐ and heteroarylboronic acid moieties under mild reaction conditions with good to excellent isolated yields. Furthermore, a theoretical investigation has been performed for the same reaction, and reaction profiles are modelled using modern density functional theory (DFT). DFT‐based results support the experimentally observed results. [ABSTRACT FROM AUTHOR]