High Resolution TEM Characterisation of Hydrogen Peroxide Treated Tooth Structures

Objective: Previous studies reported that bleaching agents are capable of altering the outer enamel or exposed dentine surfaces. In this study, transmission electron microscopy (TEM) characterisation in combination with energy dispersive x-ray spectroscopy (EDS) elemental mapping was performed to investigate the effect of hydrogen peroxide (HP) on the sub-surface of tooth structures. Materials and Methods: Bovine incisors (n=6) were assigned to three groups for treatments: 30% H2 O2 pH 3, 30% H2 O2 pH 7 and 1M sodium hydroxide (NaOH) for 16 hours. Samples were exposed to direct treatment with agents to allow easy access of the agents and uniform treatment across the entire sample sub-surfaces. Specimens were immersed in Karnovsky’s fixative for three days, embedded in epoxy and polished. Using focussed ion beam (FIB), samples were milled ~50-100 µm below the treated polished surface to feature the ultra-fine structures for TEM analysis. Results: Enamel rods, inter-rods and crystalline structures within rods were discerned for sound and H2 O2 treated enamel. No structural difference in the mineral dense peritubular region or fibrous protein rich inter-tubular dentine was observed after acidic or neutral H2 O2 treatment. A complete loss in the structural integrity of enamel rod was observed after NaOH treatment for 16 hours without having any impact on dentine structure. Conclusions: TEM analysis produced high quality sub-surface images of tooth structures and revealed no deleterious effect on the structural integrity of the sub-surface enamel or dentine after direct bleaching with hydrogen peroxide

Data are inadequate to test whale falls as chemosynthetic stepping-stones using network analysis: faunal overlaps do support a stepping-stone role

© 2017 The Authors. Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/4.0/, which permits unrestricted use, provided the original author and source are credited

Field plate optimization in low-power high-gain source-gated transistors

Source-gated transistors (SGTs) have potentially very high output impedance and low saturation voltages, which make them ideal as building blocks for high-performance analog circuits fabricated in thin-film technologies. The quality of saturation is greatly influenced by the design of the field-relief structure incorporated into the source electrode. Starting from measurements on self-aligned polysilicon structures, we show through numerical simulations how the field plate (FP) design can be improved. A simple source FP around 1 μm long situated several tens of nanometers above the semiconductor can increase the low-voltage intrinsic gain by more than two orders of magnitude and offers adequate tolerance to process variations in a moderately scaled thin-film SGT. © 2012 IEEE

The core phageome and its interrelationship with preterm human milk lipids

\ua9 2023 The AuthorsPhages and lipids in human milk (HM) may benefit preterm infant health by preventing gastrointestinal pathobiont overgrowth and microbiome modulation. Lipid association may promote vertical transmission of phages to the infant. Despite this, interrelationships between lipids and phages are poorly characterized in preterm HM. Shotgun metagenomics and untargeted lipidomics of phage and lipid profiles from 99 preterm HM samples reveals that phages are abundant and prevalent from the first week and throughout the first 100 days of lactation. Phage-host richness of preterm HM increases longitudinally. Core phage communities characterized by Staphylococcus- and Propionibacterium-infecting phages are significantly correlated with long-chain fatty acid abundances over lactational age. We report here a phage-lipid interaction in preterm HM, highlighting the potential importance of phage carriage in preterm HM. These results reveal possible strategies for phage carriage in HM and their importance in early-life microbiota development

Performance improvements in polysilicon source-gated transistors

The source-gated transistor (SGT) is a new type of transistor in which the current is controlled by a potential barrier at the source and by a gate which modulates the effective height of the source barrier. It is an ideal device architecture to be used with the low mobility materials typically applied to large area electronics, as it provides low saturation voltages and high output impedances. Furthermore, the high internal fields and low concentration of excess carriers lead to higher speed and better stability compared with FETs, particularly in disordered, low mobility semiconductors. As such, the SGT is especially well suited to thin-film analog circuits