Proteome difference among the salivary proteins adsorbed onto metallic orthodontic brackets and hydroxyapatite discs

The aim of this study was to investigate the atomic composition and the proteome of the salivary proteins adsorbed on the surface of orthodontic metallic bracket. For this, the atomic composition of orthodontic metallic brackets was analyzed with X-ray Photoelectron Spectroscopy (XPS). The acquired bracket pellicle was characterized after brackets were immersed in human whole saliva supernatant for 2 hours at 37°C. Hydroxyapatite (HA) discs were used as a control. Acquired pellicle was harvested from the HA discs (n = 12) and from the metallic brackets (n = 12). Proteomics based on mass spectrometry technology was used for salivary protein identification and characterization. Results showed that most of the proteins adsorbed on the surface of orthodontic metallic brackets and on the HA discs were identified specifically to each group, indicating a small overlapping between the salivary proteins on each study group. A total of 311 proteins present on the HA discs were unique to this group while 253 proteins were unique to metallic brackets, and only 45 proteins were common to the two groups. Even though most proteins were unique to each study group, proteins related to antimicrobial activity, lubrication, and remineralization were present in both groups. These findings demonstrate that the salivary proteins adsorbed on the bracket surface are dependent on the material molecular composition.

A chemoinformatic analysis of atoms, scaffolds and functional groups in natural products

In the quest to know why natural products (NPs) have often been considered as privileged scaffolds for drug discovery purposes, many investigations into the differences between NPs and synthetic compounds have been carried out. Several attempts to answer this question have led to the investigation of the atomic composition, scaffolds and functional groups (FGs) of NPs, in comparison with synthetic drugs analysis. This chapter briefly describes an atomic enumeration method for chemical libraries that has been applied for the analysis of NP libraries, followed by a description of the main differences between NPs of marine and terrestrial origin in terms of their general physicochemical properties, most common scaffolds and “drug-likeness” properties. The last parts of the work describe an analysis of scaffolds and FGs common in NP libraries, focusing on huge NP databases, e.g. those in the Dictionary of Natural Products (DNP), NPs from cyanobacteria and the largest chemical class of NP – terpenoids.

Effect of Electrolyte Anion on Electrochemical Behavior of Nickel Hexacyanoferrate Electrode in Aqueous Sodium-Ion Batteries

Nickel hexacyanoferrate (NiHCF) has a three-dimensional open framework structure, excellent long-cycling stability and rate performance as a cathode for aqueous sodium-ion batteries. However, the specific capacity of NiHCF is lower than that of present cathodes for aqueous batteries. A sodium-ion electrolyte was explored to achieve optimum capacity with NiHCF. Powder-type NiHCF was fabricated by coprecipitation with the atomic composition K0.065Ni1.44Fe(CN)6·4.4H2O. The presence of Fe vacancies in the atomic composition is attributable to the inclusion of coordinating and zeolitic water during coprecipitation. Two sodium-ion electrolytes, 1 M Na2SO4 and 1 M NaNO3, were employed to analyze the electrochemical behavior of the NiHCF electrode. Identical redox potentials to 0.58 V (vs. NHE) were measured in both electrolytes. However, a lower overpotential was observed in NaNO3 compared to Na2SO4 as a result of the smaller interfacial charge transfer resistance. The lower charge transfer resistance in the NaNO3 solution produced a higher specific capacity of 57 mAh g^-1 (1 C-rate) and the superior capacity retention of 46.6% at 20 C-rate. The anion in the aqueous electrolyte changed the charge transfer resistance at the electrode/electrolyte interface, confirming the electrolyte anion has a crucial effect on the charge capacity and rate performance of NiHCF.

Measuring the atomic composition of planetary building blocks

Context. Volatile molecules are critical to terrestrial planetary habitability, yet they are difficult to observe directly where planets form at the midplanes of protoplanetary disks. It is unclear whether the inner ∼1 AU of disks are volatile-poor or if this region is resupplied with ice-rich dust from colder disk regions. Dust traps at radial pressure maxima bounding disk gaps can cut off the inner disk from these types of volatile reservoirs. However, the trap retention efficiency and atomic composition of trapped dust have not been measured. Aims. We present a new technique to measure the absolute atomic abundances in the gas accreting onto T Tauri stars and infer the bulk atomic composition and distribution of midplane solids that have been retained in the disk around the young star TW Hya. Methods. We identify near-infrared atomic line emission from gas-phase material inside the dust sublimation rim of TW Hya. Gaussian decomposition of the strongest H Paschen lines isolates the inner disk hydrogen emission. We measure several key elemental abundances, relative to hydrogen, using a chemical photoionization model and infer dust retention in the disk. With a 1D transport model, we determine approximate radial locations and retention efficiencies of dust traps for different elements. Results. Volatile and refractory elements are depleted from TW Hya’s hot gas by factors of ∼102 and up to 105, respectively. The abundances of the trapped solids are consistent with a combination of primitive Solar System bodies. Dust traps beyond the CO and N2 snowline cumulatively sequester 96% of the total dust flux, while the trap at 2 AU, near the H2O snowline, retains 3%. The high depletions of Si, Mg, and Ca are explained by a third trap at 0.3 AU with >95% dust retention. Conclusion. TW Hya sports a significant volatile reservoir rich in C- and N-ices in its outer submillimeter ring structure. However, unless the inner disk was enhanced in C by earlier radial transport, typical C destruction mechanisms and the lack of a C resupply should leave the terrestrial planet-forming region of TW Hya “dry” and carbon-poor. Any planets that form within the silicate dust trap at 0.3 AU could resemble Earth in terms of the degree of their volatile depletion.