Logo: to the web site of Uppsala University

Although graphite-based composite electrodes currently are widely used as negative electrodes in lithium-ion batteries due to their good cycle performances, improvements of their long-time cycling stability are still desirable. Herein, a series of lithium-metal half-cell experiments is performed to demonstrate that the diffusion-controlled lithium-trapping effect constitutes an additional, and so far, largely unrecognized, aging mechanism for graphite-based electrodes. This trapping effect, which stems from incomplete delithiation due to diffusion-controlled redistribution of intercalated lithium in graphite, is shown to account for around 30% of the total accumulated capacity loss during long-time cycling. The trapping effect is caused by the concentration gradients present at the end of the lithiation steps as these gradients result in lithium (i.e., coupled Li+ and e(-)) diffusion in the electrodes. As a result, a small fraction of the lithium becomes inaccessible on the timescale of the subsequent delithiation step. The results, however, also show that the inclusion of constant-voltage delithiation steps can increase the delithiation efficiency and decrease the influence of the lithium-trapping effect. This work consequently demonstrates that diffusion-controlled lithium-trapping effects need to be considered when trying to increase the lifetimes of graphite-based electrodes.

Using 𝑒+⁢𝑒− annihilation data corresponding to an integrated luminosity of 6.32  fb−1 collected at center-of-mass energies between 4.178 and 4.226 GeV with the BESIII detector, we perform the first amplitude analysis of the decay 𝐷+𝑠→𝐾0𝑆⁢𝐾+⁢𝜋0 and determine the relative branching fractions and phases for intermediate processes. We observe an 𝑎0-like state with mass of 1.817 GeV in its decay to 𝐾0𝑆⁢𝐾+ for the first time. In addition, we measure the ratio {ℬ⁡[𝐷+𝑠→¯𝐾*⁢(892)0⁢𝐾+]/ℬ⁡[𝐷+𝑠→¯𝐾0⁢𝐾*⁢(892)+]} to be 2.35+0.42−0.23⁢stat±0.1⁢0syst. Finally, we provide a precision measurement of the absolute branching fraction ℬ⁡(𝐷+𝑠→𝐾0𝑆⁢𝐾+⁢𝜋0)=(1.46±0.0⁢6stat±0.0⁢5syst)%.

The wild boar (Sus scrofa) is becoming more common in Europe and has potential to be used as sentinel species for local contamination of heavy metals. Concentrations of nine trace elements (arsenic (As), cadmium (Cd), copper (Cu), iron (Fe), lead (Pb), magnesium (Mg), manganese (Mn), selenium (Se), and zinc (Zn)) were examined in kidney tissue of 104 female wild boars hunted at three sites in Sweden. The interrelationships between the trace elements and age dependency were investigated. Reproductive health was previously known to differ among animals at the different study sites, but could not be explained by heavy metal concentrations and no associations were found between heavy metals and reproductive parameters. Kidney concentrations of Cd (mean 4.16 mg/kg wet weight (w.w.), range 0.16-12.8) were higher than the permissible level for human consumption in 99.9% of the samples. Pb concentrations were generally intermediate or low (mean 0.14 mg/kg w.w., range 0.03-1.01) and exceeded the levels accepted for human consumption in 0.02% of the samples. Age class was significantly associated with the concentrations of Cd, Mg, and Mn. Concentrations of As were low (mean 0.02 mg/kg w.w., range <0.0001-0.08) and Cu and Se concentrations were within the ranges of suspected deficiency for 10% and 4% of the wild boars, respectively.

In this study, the relationship between the nitrogen content and the corrosion resistances of non-equimolar multicomponent AlCrNbYZrN films (N = 13-49 at.%) is probed. While there was no linear relationship between nitrogen content and corrosion resistance, the results clearly show that the corrosion resistances of the films were instead determined by their nitrogen-induced porosities i.e. the less porous the sample, the higher the corrosion resistance. The 23, 30 and 37 at.% N samples were denser while the 13 at.% N sample was porous and the 49 at.% N film had an underdense nanocrystalline columnar cross section permitting the ingress of electrolyte.

In this study, we used proteomics in conjunction with microscopy to study differences in the proteome and hyphal morphology of the copper tolerant soft rot fungus Phialophora malorum grown in media containing 0.064, 0.64% Cu as CuSO4. Unique proteins were found in the control and the copper-treated (0.064% CuSO4) samples. Of five unique proteins found in the 0.064% CuSO4 treated cultures, ATP synthase subunit alpha is considered to play an important role in copper tolerance as it is involved in the biosynthesis of fatty acids and steroids and may relate to morphological changes associated with hyphal cell walls of the fungus when grown in the presence of copper. ICP-AES analyses showed total mycelial Cu to increase with media Cu with 5246- and 16535 mu g Cu/g dry wt mycelia respectively found in 0.064 and 0.64% Cu-cultures after 6 weeks growth. Rubeanic acid staining of 0.064% mycelia showed Cu bound in intracellular bodies while most Cu was found as extracellular precipitates on the surfaces of hyphae in 0.64% Cu. SEM showed hyphal surfaces enrobed in fibrillar polysaccharides to which Cu was bound.

While the use of silicon‐based electrodes can increase the capacity of Li‐ion batteries considerably, their application is associated with significant capacity losses. In this work, the influences of solid electrolyte interphase (SEI) formation, volume expansion, and lithium trapping are evaluated for two different electrochemical cycling schemes using lithium‐metal half‐cells containing silicon nanoparticle–based composite electrodes. Lithium trapping, caused by incomplete delithiation, is demonstrated to be the main reason for the capacity loss while SEI formation and dissolution affect the accumulated capacity loss due to a decreased coulombic efficiency. The capacity losses can be explained by the increasing lithium concentration in the electrode causing a decreasing lithiation potential and the lithiation cut‐off limit being reached faster. A lithium‐to‐silicon atomic ratio of 3.28 is found for a silicon electrode after 650 cycles using 1200 mAhg⁻¹ capacity limited cycling. The results further show that the lithiation step is the capacity‐limiting step and that the capacity losses can be minimized by increasing the efficiency of the delithiation step via the inclusion of constant voltage delithiation steps. Lithium trapping due to incomplete delithiation consequently constitutes a very important capacity loss phenomenon for silicon composite electrodes.

Gold is widely used as the electrode material in different chemi- and biosensing applications while cyclic voltammetry (CV) in sulfuric acid solutions is a commonly employed method for gold surface preparation and characterization. However, as shown herein, chloride leakage from the Ag/AgCl/sat. KCl reference electrode and platinum dissolution from the platinum counter electrode can severely compromise the reproducibility and hence the reliability of the prepared gold electrodes. The aim of this work is to obtain a comprehensive understanding of the separate and interdependent effects of the aforementioned factors on the voltammetric behavior of microfabricated polycrystalline gold electrodes. It is shown that the leakage of chloride gives rise to etching of both the gold working and the platinum counter electrodes and that the chloride concentration has a strong influence on the ratio between the obtained gold and platinum concentrations in the electrolyte. The dissolved gold and platinum are then re-deposited on the gold electrode on the cathodic voltammetric scan, changing the structure and properties of the electrode. It is also demonstrated that the changes in the properties of the gold electrode are determined by the ratio between the co-deposited platinum and gold rather than the absolute amount of platinum deposited on the gold electrode. In addition, the chloride and sulfate adsorption behavior on the gold electrode is carefully investigated. It is proposed that redox peaks due to the formation ofthe corresponding Au(I) complexes can be seen in the double layer region of the voltammogram. The results show that the chloride leakage from the reference electrode needs to be carefully controlled and that platinum counter electrodes should be avoided when developing gold sensing electrodes. The present comprehensive understanding of the electrochemical performance of gold electrodes prepared using CV should be of significant importance in conjunction with both fundamental investigations and practical applications.

Objectives: The aim of this study was to investigate the titanium (Ti) content of biopsies from patients with severe peri-implantitis or controls without Ti exposure.

Background: Peri-implantitis is considered to be an infectious disease, but recent studies have shown that Ti can aggravate inflammation in combination with bacterial products. The Ti content of peri-implantitis and periodontitis (controls) tissue is unknown.

Methods: Thirteen patients referred for peri-implantitis and eleven for periodontitis treatment were included in the study. Disease severity was obtained from dental records. Biopsies were taken from both groups and chemically analysed with inductively coupled plasma mass spectrometry for Ti content. Additionally, two patients with peri-implantitis and two with periodontitis were recruited and their biopsies were analysed microscopically with light microscopy, transmission electron microscopy and scanning electron microscopy with element analysis to investigate the presence of particulate Ti.

Results: All patients lost one or more implants despite undergoing peri-implant or treatment. Peri-implantitis tissue contained significantly higher concentrations of Ti than control samples with a mean +/- SD of 98.7 +/- 85.6 and 1.2 +/- 0.9 mu g/g, respectively. Particulate metal was identified in peri-implantitis and control biopsies, but element analyses could confirm only the presence of Ti in peri-implantitis tissue.

Conclusion: We showed that high contents of particulate and submicron Ti were present in peri-implantitis tissue. These high Ti contents in peri-implant mucosa can potentially aggravate inflammation, which might reduce the prognosis of treatment interventions.

A comprehensive understanding of the cyclic voltammetry (CV) for gold surfaces is essential for advanced applications. In the present study, a series of experiments were designed to investigate CV for gold under different experimental conditions when using a conventional configuration of a Ag/AgCl/sat. KCl reference electrode and a platinum wire counter electrode. The interferences introduced by the configuration were reflected in the three fingerprint regions of the voltammograms. It was found that the shape of the voltammograms was less reproducible at a lower sample volume when the cycle number was increased. This observation could be explained by different concentrations of Cl^- leaking from the reference electrode and platinum dissolved from the counter electrode. The reproducibility of the gold oxidation and reduction (Ox/Re) region in the voltammograms was improved when gold dissolution and re-deposition caused by Cl^- leakage was eliminated by using a bridge. In the hydrogen evolution and oxidation reactions (HER/HOR) region the catalytic performance of the gold electrode could be minimized by replacing the platinum counter electrode with a graphite rod. Alternatively, it could be enhanced by increasing the surface ratio of the co-deposited platinum to gold. In the electric double layer (EDL) region, peaks dependent on the concentrations of Cl^- and SO₄^2- were observed. To account for the occurrence of these peaks, a new mechanism based on the formation of neutral gold (I) complexes at very low Au⁺ concentrations, was proposed. 

Inflammation and bone reduction around dental implants are described as peri-implantitis and can be caused by an inflammatory response against bacterial products and toxins. Titanium (Ti) forms aggregates with serum proteins, which activate and cause release of the cytokine interleukin (IL-1) from human macrophages. It was hypothesized that cobalt (Co) ions can interact in the formation of pro-inflammatory aggregates, formed by titanium. To test this hypothesis, we differentiated THP-1 cells into macrophages and exposed them to Ti ions alone or in combination with Co ions to investigate if IL-1 release and cytotoxicity were affected. We also investigated aggregate formation, cell uptake and human biopsies with inductively coupled plasma atomic emission spectroscopy and electron microscopy. Co at a concentration of 100 mu M neutralized the IL-1 release from human macrophages and affected the aggregate formation. The aggregates formed by Ti could be detected in the cytosol of macrophages. In the presence of Co, the Ti-induced aggregates were located in the cytosol of the cultured macrophages, but outside the lysosomal structures. It is concluded that Co can neutralize the Ti-induced activation and release of active IL-1 from human macrophages in vitro. Also, serum proteins are needed for the formation of metal-protein aggregates in cell medium. Furthermore, the structures of the aggregates as well as the localisation after cellular uptake differ if Co is present in a Ti solution. Phagocytized aggregates with a similar appearance seen in vitro with Ti present, were also visible in a sample from human peri-implant tissue.