High-performance aqueous rechargeable NiCo//Zn battery with molybdate anion intercalated CoNi-LDH@CP bilayered cathode

Seeking cathode materials with high areal capacity and excellent cycling tolerance is a key step to develop aqueous rechargeable zinc-based alkaline batteries with high energy density, power density and excellent stability. Here, the bilayered cathode composite (MCN-LDH@CP) of molybdate intercalated cobalt-nickel layered hydroxide nanosheets (MCN-LDH) grown on cobalt phosphate octahydrate microsheet (CP) was prepared by a two-step hydrothermal process. Molybdate intercalation significantly reduces the thickness of cobalt-nickel layered hydroxide, greatly increases its specific surface area, regulates its pore distribution, increases the crystal plane spacing, promotes the diffusion rate of hydroxide in it, and increases its specific capacity. Meanwhile, the bilayered MCN-LDH@CP electrode significantly improved the areal energy density (2.89 mWh/cm2) and peak power density (111.22 mW/cm2) and cycle stability (97.8 % after 7000 cycles) of the CoNi//Zn battery. The excellent stability is mainly due to the fact that the MCN-LDH overlay inhibits the loss of P element of CP and improves the structural stability of the sample. The quasi-solid-state MCN-LDH@CP//Zn battery can still charge a mobile phone even when hammered and pierced, showing excellent safety and reliability. This work opens a new avenue to develop CoNi//Zn batteries with high energy density, power density and excellent tolerance.

Designed a novel EP + GO/ZRC + GO coating with bilayered structure for enhancing corrosion resistance of steel substrate

The study aimed to provide an effective way to combine the advantages of both the zinc-rich epoxy coating and the graphene-based coating. Herein, we introduce ZRC + GO/EP + GO and EP + GO/ZRC + GO coatings with bilayered structure. In addition, the bilayered ZRC, ZRC + GO and EP + GO coatings were also fabricated to comparatively investigate the anticorrosion mechanisms of the coatings. In order to obtain better dispersion of GO in waterborne coatings, ionic liquid (1-aminoethyl-3-methylimidazolium bromide) was successively grafted on GO, which was confirmed by XPS, Raman and FT-IR results. The results obtained from electrochemical impedance spectroscopy (EIS) and salt spray test proved that the as-prepared EP + GO/ZRC + GO coating presented superior corrosion protection which was derived from the synergistic effect of barrier property and cathodic protection endowed by the special bilayered structure of the coating. Besides, SEM, EDS and XRD results of the coating-exfoliated steel substrates also revealed the steel substrate coated by EP + GO/ZRC + GO was not obviously corroded at the end of the immersion.

Direct bilayered biomimetic composite restoration: The effect of a cusp-supporting short fiber-reinforced base design on the chewing fracture resistance and failure mode of molars with or without endodontic treatment

The aim of this study was to assess the chewing fracture resistance of compromised molars restored with direct composite resin (CR) restorations, with and without a short-fiber reinforcing (short-FRC) base. Wide extension of MOD cavities with removed palatal cusps preparations were simulated on 48 extracted maxillary molars. Five groups (n = 12) were designed: 1. control (intact teeth), 2. non-endodontically treated and 3. endodontically treated teeth with direct CR restorations (GC-Posterior), and 4. non-endodontically treated and 5. endodontically treated teeth with direct biomimetic bilayered restorations. Groups 4 and 5 included an anatomically shaped short-FRC base (everX Posterior), covered with a 2 mm CR layer (GC-Posterior). Restorations were subjected to chewing in water (1.5 Hz), with load of 85 N. Specimens were loaded until fracture or to a maximum of 120 000 cycles. Restorations that survived the chewing cycle were submitted to static load test (post-chewing test). The data were statistically analyzed using two-way ANOVA (p = 0.05) and fracture types with the chi-square test (p = 0.05). Fractures were classified into reparable, possibly reparable or non-reparable. All specimens survived the chewing cycle. The chewing fracture resistance of the direct biomimetic restorations prepared on non-endodontically treated teeth (2889 N) was statistically significantly higher than the direct CR counterparts (1966 N) (p = 0.00015), which was not the case for the groups with endodontically treated teeth (p = 0.257). Inclusion of a short-FRC base also influenced the fracture type resulting in most reparable fractures (67-75% versus 25% for biomimetic and CR groups respectively) (p = 0.054). Anatomically shaped i.e. a cusp-supporting design made of short-FRC base (everX Posterior) improved the chewing fracture resistance and fracture manner of compromised molars regardless of whether they were endodontically treated or not.

Influence of veneer pore defects on fracture behavior of bilayered lithium disilicate glass-ceramic crowns

OBJECTIVE

To identify the conditions under which fabrication pore defects within veneering porcelain in bilayered lithium disilicate glass-ceramic (LDG) crowns will influence and jeopardize the mechanical integrity of the structure.

METHODS

Thirty standardized molar crowns (IPS e.max Press) were fabricated and microCT scanned to 3D-analyze the size, morphology and distribution of pores in veneering porcelain, followed by in vitro fracture test and SEM fractographic observation. Finite element analysis (FEA) of the microCT reconstructed models was used to evaluate the stress state.

RESULTS

The volumes of pores in samples ranged from 3241μm³ to 1.29×10⁹μm³ with the equivalent radius between 10μm to 680μm. Deviation of sphericity of pores ranged from 0.10 to 0.81 and the average of 99.97% pores was near 0.63. For the smaller pores their distribution tended to be uniform, while the larger pores were irregular with elongated ellipsoidal form and located at or near the veneer-core interface. During wedge loading blunt contact fracture testing 21 crowns failed from the fissure on the occlusal surface, of which 16 failed from surface or near surface pores, 2 from the midpoint of the oblique ridge, and 7 from larger interfacial pores. FEA analysis indicated that defects were detrimental to veneer integrity only in regions of tensile stress and where the pore radius associated with crack initiation ranged from 30 to 50μm. Pore morphology appeared to have only a minor effect on fracture.

SIGNIFICANCE

Within the limitation of the microCT resolution and FEA, it suggests that pores radius large than 30-50μm and located in the tensile stress area like grooves and fissures on the occlusal surface or near surface as well as cervical margins of veneering porcelain will jeopardize the bilayered structure and mechanical integrity of LDG.

Esophageal carcinoma originating in the surface epithelium with immunohistochemically proven esophageal gland duct differentiation: A case report

A case of esophageal carcinoma exclusively composed of adenocarcinoma simulating an esophageal gland duct in a 61-year-old man is presented. The tumor arose as a slightly elevated lesion in the middle intrathoracic esophagus. It was almost completely overlaid with non-neoplastic stratified squamous epithelial cells. Beneath the overlying surface epithelium, an adenocarcinoma that was bilayered in structure diffusely invaded both the mucosal and submucosal layers. Although the tumor consisted exclusively of adenocarcinomatous cells, a keratinizing squamous cell carcinoma component was focally observed. The invasive carcinoma was focally continuous with the small area of the surface squamous epithelial layer, which was confirmed to be neoplastic by immunohistochemistry. Morphological and immunohistochemical examinations suggested that the adenocarcinomatous component arose from the esophageal surface epithelium and clearly differentiated into an esophageal gland duct. It is important to consider the possibility of this type of adenocarcinoma when diagnosing a ductal or glandular lesion of the esophagus in small biopsy specimens.