Photoemission investigation of the electronic structure of Fe-Pd and Fe-Pt alloys

A photoemission investigation of Fe-Pd and Fe-Pt transition-metal alloys, using ∼50–150-eV synchrotron radiation, is presented. We consider in particular the spectral distribution of Fe states when approaching the dilute limit. By means of the Cooper minimum in the 4d and 5d photoionization cross section, we identify structures that have mainly Fe minority- or Fe majority-spin character. The relative position of these peaks is discussed in terms of the covalent interaction between Fe 3d and Pd or Pt d states. Also, the strong resemblance between the distribution of Fe states in the Pd-based and in the Pt-based alloys is demonstrated. We find a consistent behavior of interacting d states towards the dilute limit. It is concluded that the Fe states that are observed in the photoemission spectra of the dilute alloys have mainly majority-spin character and are, because of the covalent interaction with host states, widely distributed over the energy range of the host d band. The Fe minority-spin band, which is centered near the Fermi level, gradually empties with increasing Fe dilution

ABRASIVE WEAR BY TiO 2 ON HARD AND LOW FRICTION COATINGS

ABSTRACT Several components in paint and plastic industry, like mixers, extrusion screws and dies, injection moulds, suffer heavily from abrasive wear. This wear is mainly induced by the presence of TiO 2 in the paint or in the plastic blend. Coating technology offers a solution to increase the wear resistance and consequently the lifetime of those components. The aim of this study is the evaluation of the micro-abrasive wear resistance of a range of commercially available hard and/or low friction coatings against rutile particles. Therefore, ball cratering tests EXPERIMENTAL SET-UP The tests were performed on a TE66 micro-scale abrasion tester manufactured by Plint. As abrasive suspensions, a typical rutile powder with small particle size (Ø 0.1-0.4 µm) and spherical grains in distilled water was used. Ball bearing steel was used as counterbody. The selected coatings ranged from hard ceramic coatings to softer low friction coatings. Four PVD coatings were used (TiN, CrN, TiCN and low temperature CrN), one CVD (TiN) and three PACVD (DLC and diamond-like nanocomposites Dylyn ® a-C:H/a-Si:O) TEST RESULTS AND EVALUATION The micro abrasion test resulted in a clear ranking of the selected coatings in function of the wear coefficient. In general, the hard ceramic coatings have the lowest wear coefficient. DLC and CrN performed very well. The softer coating types which are designed for reduction of the surface energy, such as NiP+PTFE, show an increase in wear of three orders of magnitude. However, there is no evidence for a close correlation between the wear rate and the coating hardness measured by depth sensing indentation. Only when the three very similar PACVD coatings are considered separately, the wear coefficient is significantly increasing with decreasing coating hardness. The results are obtained by using the extended Archard equation: with K c and K s are the wear coefficients of the coating and substrate respectively, V c and V s the measured wear volumes and SN the sliding distance multiplied by the applied load. Different ways of implementing equatio

Marine biogenics in sea spray aerosols interact with the mTOR signaling pathway

Sea spray aerosols (SSAs) have profound effects on our climate and ecosystems. They also contain microbiota and biogenic molecules which could affect human health. Yet the exposure and effects of SSAs on human health remain poorly studied. Here, we exposed human lung cancer cells to extracts of a natural sea spray aerosol collected at the seashore in Belgium, a laboratory-generated SSA, the marine algal toxin homoyessotoxin and a chemical inhibitor of the mammalian target of rapamycin (mTOR) pathway. We observed significant increased expression of genes related to the mTOR pathway and Proprotein convertase subtilisin/kexin type 9 (PCSK9) after exposure to homoyessotoxin and the laboratory-generated SSA. In contrast, we observed a significant decrease in gene expression in the mTOR pathway and of PCSK9 after exposure to the natural SSA and the mTOR inhibitor, suggesting induction of apoptosis. Our results indicate that marine biogenics in SSAs interact with PCSK9 and the mTOR pathway and can be used in new potential pharmaceutical applications. Overall, our results provide a substantial molecular evidence base for potential beneficial health effects at environmentally relevant concentrations of natural SSAs

The Lantern Vol. 13, No. 1, October 1944

• One Doctor\u27s Story • Sonnet for a Friend • Lines and a Sonnet • Chant • Circus Impressions • Spring Comes Latehttps://digitalcommons.ursinus.edu/lantern/1034/thumbnail.jp

The 600 yr eruptive history of Villarrica Volcano (Chile) revealed by annually laminated lake sediments

Lake sediments contain valuable information about past volcanic and seismic events that have affected the lake catchment, and they provide unique records of the recurrence interval and magnitude of such events. This study uses a multilake and multiproxy analytical approach to obtain reliable and high-resolution records of past natural catastrophes from similar to 600-yr-old annually laminated (varved) lake sediment sequences extracted from two lakes, Villarrica and Calafquen, in the volcanically and seismically active Chilean Lake District. Using a combination of micro-X-ray fluorescence (mu XRF) scanning, microfacies analysis, grain-size analysis, color analysis, and magnetic-susceptibility measurements, we detect and characterize four different types of event deposits (lacustrine turbidites, tephra-fall layers, runoff cryptotephras, and lahar deposits) and produce a revised eruption record for Villarrica Volcano, which is unprecedented in its continuity and temporal resolution. Glass geochemistry and mineralogy also reveal deposits of eruptions from the more remote Carran-Los Venados volcanic complex, Quetrupillan Volcano, and the Huanquihue Group in the studied lake sediments. Time-series analysis shows 112 eruptions with a volcanic explosivity index (VEI) >= 2 from Villarrica Volcano in the last similar to 600 yr, of which at least 22 also produced lahars. This significantly expands our knowledge of the eruptive frequency of the volcano in this time window, compared to the previously known eruptive history from historical records. The last VEI >= 2 eruption of Villarrica Volcano occurred in 1991. Based on the last similar to 500 yr, for which we have a complete record from both lakes, we estimate the probability of the occurrence of future eruptions from Villarrica Volcano and statistically demonstrate that the probability of a 22 yr repose period (anno 2013) without VEI >= 2 eruptions is <= 1.7%. This new perspective on the recurrence interval of eruptions and historical lahar activity will help improve volcanic hazard assessments for this rapidly expanding tourist region, and it highlights how lake records can be used to significantly improve historical eruption records in areas that were previously uninhabited

Trigonometric Parallaxes of Central Stars of Planetary Nebulae

Trigonometric parallaxes of 16 nearby planetary nebulae are presented, including reduced errors for seven objects with previous initial results and results for six new objects. The median error in the parallax is 0.42 mas, and twelve nebulae have parallax errors less than 20 percent. The parallax for PHL932 is found here to be smaller than was measured by Hipparcos, and this peculiar object is discussed. Comparisons are made with other distance estimates. The distances determined from these parallaxes tend to be intermediate between some short distance estimates and other long estimates; they are somewhat smaller than estimated from spectra of the central stars. Proper motions and tangential velocities are presented. No astrometric perturbations from unresolved close companions are detected.Comment: 24 pages, includes 4 figures. Accepted for A

A comparative study between catalase gene therapy and the cardioprotector monohydroxyethylrutoside (MonoHER) in protecting against doxorubicin-induced cardiotoxicity in vitro

50) limited the possibility to increase catalase activity more than 3.5-fold, which was not enough to protect infected NeRCaMs against doxorubicin-induced cardiotoxicity and (2) confirms the efficacy of monoHER as a cardioprotector. Thus, the use of monoHER proves more suitable for the prevention of doxorubicin-induced cardiotoxicity than catalase gene transfer employing adenovirus vectors