Impact of minor sulfur additions on the structure and dynamics of Ni-Nb melts

Bulk metallic glasses feature an amorphous structure, which results in exceptional properties as engineering materials. Typically alloying additional components improves the glass forming ability (GFA). Beside adding non-metallic elements like P, B, C, recently sulfur has been found to facilitate bulk metallic glasses formation at different concentration levels [1]. This makes them promising candidates for commercialization, where the alloy composition can be tuned according to applications. In the case of the binary Nig2Nb3g glass forming alloy, it has been found that an optimal enhancement of the GFA can be achieved by alloying only 3 at% S. Such kind of minor alloying effects cannot be understood by applying the common empirical rules like a denser packing of the melt, or the formation of deep eutectic compositions. Employing electrostatic levitation combined with in-situ synchrotron diffraction, we studied impacts of sulfur on the structure and dynamics of Ni-Nb based alloys, as well as on the solidification behavior from undercooled melt. First results show that small, but notable changes can be observed in the measured liquid structure factor upon an addition of 3 at% S. In particular, in the obtained X-ray total structure factor the position of the first structure factor maximum appears to shift towards lower g values. The structure changes are analyzed with the help of the partial structure factors of the binary Ni-Nb alloy [2]. It has been also observed that the initial phases solidified from the undercooled melt seem to be different with and without S. The implication of these changes on the glass forming behavior is discussed together with the melt viscosity measured using the oscillating drop technique. References: [1] A. Kuball, O. Gross, B. Bochtler, R. Busch, Scr. Mater. 146, 73-76 (2018). [2] D. Holland-Moritz, F. Yang, J. Gegner, T. Hansen, M. D. Ruiz-Martin, and A. Meyer, J. Appl. Phys. 115, 203509 (2014)

Investigation of the Tribological Behaviour of Various AMC Surfaces against Brake Lining Material

AlSi7Mg/SiCp aluminium matrix composites (AMCs) with a high ceramic content (35 vol.%) that were produced by using the field-assisted sintering technique (FAST) were subjected to tribological preconditioning and evaluated as a potential lightweight material to substitute grey cast iron brake discs. However, since an uncontrolled running-in process of the AMC surface can lead to severe wear and thus to failure of the friction system, AMC surfaces cannot be used directly after finishing and have to be preconditioned. A defined generation of a tribologically conditioned surface (tribosurface) is necessary, as was the aim in this study. To simulate tribological conditions in automotive brake systems, the prepared AMC samples were tested in a pin-on-disc configuration against conventional brake lining material under dry sliding conditions. The influence of the surface topography generated by face turning using different indexable inserts and feeds or an additional plasma electrolytic treatment was investigated at varied test pressures and sliding distances. The results showed that the coefficient of friction remained nearly constant when the set pressure was reached, whereas the initial topography of the samples studied by SEM varied substantially. A novel approach based on analysing the material ratio determined by 3D surface measurement was developed in order to obtain quantitative findings for industrial application

Ultrasonic-Vibration-Superimposed Face Turning of Aluminium Matrix Composite Components for Enhancing Friction-Surface Preconditioning

Aluminium matrix composites (AMCs) represent an important group of high-performance materials. Due to their specific strength and a high thermal conductivity, these composites have been considered for the large-scale production of brake discs. However, preconditioning the friction surfaces is necessary to avoid severe wear of both the brake discs and the brake linings. This can be achieved through controlled friction against commercially available brake-lining materials and the formation of transfer or reactive layers (tribosurfaces). Homogeneous tribosurfaces allow for nearly wear-free brake systems under moderate brake conditions. In this work, preconditioning was carried out with a pin-on-disc tester, aiming for the fast creation of homogeneously formed and stable tribosurfaces. The influence of surface microedges perpendicular to the direction of friction on the machined AMC surfaces on the build-up speed and homogeneity of the tribosurfaces was investigated. The microedges were generated using ultrasonic-vibration-superimposed face turning. Thereby, the vibration direction corresponded to the direction of the passive force. For research purposes, the distance of the microedges was changed by varying the cutting speed and feed. The experiments were carried out using AMC disc specimens with a reinforcement content of a 35% volume proportion of silicon carbide particles. Machining was realised with CVD-diamond-tipped indexable inserts. The evaluation of the generated surfaces before and after preconditioning was achieved using 3D laser scanning microscopy and scanning electron microscopy. It was demonstrated that ultrasonic-vibration-superimposed face turning effectively generated microedges on the AMC surfaces. The results show that larger distances between the microedges enhanced the formation of stable tribosurfaces. Thus, the tribosystem’s steady state was reached quickly. Therefore, the benefits of AMC-friction-surface microstructuring on the generation of tribosurfaces under laboratory conditions were proven. These findings contribute to the development of high-performance AMC brake systems

The cancer-associated microprotein CASIMO1 controls cell proliferation and interacts with squalene epoxidase modulating lipid droplet formation

Breast cancer is a leading cause of cancer-related death in women. Small open reading frame (sORF)-encoded proteins or microproteins constitute a new class of molecules often transcribed from presumed long non-coding RNA transcripts (lncRNAs). The translation of some of these sORFs has been confirmed, but their cellular function and importance remains largely unknown. Here, we report the identification and characterization of a novel microprotein of 10 kDa, which we named Cancer-Associated Small Integral Membrane Open reading frame 1 (CASIMO1). CASIMO1 RNA is overexpressed predominantly in hormone receptor-positive breast tumors. Its knockdown leads to decreased proliferation in multiple breast cancer cell lines. Its loss disturbs the organization of the actin cytoskeleton, leads to inhibition of cell motility, and causes a G(0)/G(1) cell cycle arrest. The proliferation phenotype upon overexpression is observed only with CASIMO1 protein expression, but not with a non-translatable mutant attributing the effects to the sORF-derived protein rather than a lncRNA function. CASIMO1 microprotein interacts with squalene epoxidase (SQLE), a key enzyme in cholesterol synthesis and a known oncogene in breast cancer. Overexpression of CASIMO1 leads to SQLE protein accumulation without affecting its RNA levels and increased lipid droplet clustering, while knockdown of CASIMO1 decreased SQLE protein abundance and ERK phosphorylation downstream of SQLE. Importantly, SQLE knockdown mimicked the CASIMO1 knockdown phenotype and in turn SQLE overexpression fully rescued the effect of CASIMO1 knockdown. These findings establish CASIMO1 as the first functional microprotein that plays a role in carcinogenesis and is implicated in the cell lipid homeostasis

9p24.1 alterations and programmed cell death 1 ligand 1 expression in early stage unfavourable classical Hodgkin lymphoma: an analysis from the German Hodgkin Study Group NIVAHL trial

High programmed cell death 1 ligand 1 (PD-L1) protein expression and copy number alterations (CNAs) of the corresponding genomic locus 9p24.1 in Hodgkin- and Reed-Sternberg cells (HRSC) have been shown to be associated with favourable response to anti-PD-1 checkpoint inhibition in relapsed/refractory (r/r) classical Hodgkin lymphoma (cHL). In the present study, we investigated baseline 9p24.1 status as well as PD-L1 and major histocompatibility complex (MHC) class I and II protein expression in 82 biopsies from patients with early stage unfavourable cHL treated with anti-PD-1-based first-line treatment in the German Hodgkin Study Group (GHSG) NIVAHL trial (ClinicalTrials.gov Identifier: NCT03004833). All evaluated specimens showed 9p24.1 CNA in HRSC to some extent, but with high intratumoral heterogeneity and an overall smaller range of alterations than reported in advanced-stage or r/r cHL. All but two cases (97%) showed PD-L1 expression by the tumour cells in variable amounts. While MHC-I was rarely expressed in >50% of HRSC, MHC-II expression in >50% of HRSC was found more frequently. No obvious impact of 9p24.1 CNA or PD-L1 and MHC-I/II expression on early response to the highly effective anti-PD-1-based NIVAHL first-line treatment was observed. Further studies evaluating an expanded panel of potential biomarkers are needed to optimally stratify anti-PD-1 first-line cHL treatment

Pseudorapidity densities of charged particles with transverse momentum thresholds in pp collisions at √ s = 5.02 and 13 TeV

The pseudorapidity density of charged particles with minimum transverse momentum (pT) thresholds of 0.15, 0.5, 1, and 2 GeV/c is measured in pp collisions at the center of mass energies of √s=5.02 and 13 TeV with the ALICE detector. The study is carried out for inelastic collisions with at least one primary charged particle having a pseudorapidity (η) within 0.8pT larger than the corresponding threshold. In addition, measurements without pT-thresholds are performed for inelastic and nonsingle-diffractive events as well as for inelastic events with at least one charged particle having |η|2GeV/c), highlighting the importance of such measurements for tuning event generators. The new measurements agree within uncertainties with results from the ATLAS and CMS experiments obtained at √s=13TeV.

Measurement of inclusive J/ψ\psi pair production cross section in pp collisions at s=13\sqrt{s} = 13 TeV

International audienceThe production cross section of inclusive J/$\psi$ pairs in pp collisions at a centre-of-mass energy $\sqrt{s} = 13$ TeV is measured with ALICE. The measurement is performed for J/$\psi$ in the rapidity interval $2.5 0$. The production cross section of inclusive J/$\psi$ pairs is reported to be $10.3 \pm 2.3 {\rm (stat.)} \pm 1.3 {\rm (syst.)}$ nb in this kinematic interval. The contribution from non-prompt J/$\psi$ (i.e. originated from beauty-hadron decays) to the inclusive sample is evaluated. The results are discussed and compared with data

Inclusive and multiplicity dependent production of electrons from heavy-flavour hadron decays in pp and p−-Pb collisions

International audienceMeasurements of the production of electrons from heavy-flavour hadron decays in pp collisions at $\sqrt{s} = 13$ TeV at midrapidity with the ALICE detector are presented down to a transverse momentum ($p_{\rm T}$) of 0.2 GeV$/c$ and up to $p_{\rm T} = 35$ GeV$/c$, which is the largest momentum range probed for inclusive electron measurements in ALICE. In p$-$Pb collisions, the production cross section and the nuclear modification factor of electrons from heavy-flavour hadron decays are measured in the $p_{\rm T}$ range $0.5 < p_{\rm T} < 26$ GeV$/c$ at $\sqrt{s_{\rm NN}} = 8.16$ TeV. The nuclear modification factor is found to be consistent with unity within the statistical and systematic uncertainties. In both collision systems, first measurements of the yields of electrons from heavy-flavour hadron decays in different multiplicity intervals normalised to the multiplicity-integrated yield (self-normalised yield) at midrapidity are reported as a function of the self-normalised charged-particle multiplicity estimated at midrapidity. The self-normalised yields in pp and p$-$Pb collisions grow faster than linear with the self-normalised multiplicity. A strong $p_{\rm T}$ dependence is observed in pp collisions, where the yield of high-$p_{\rm T}$ electrons increases faster as a function of multiplicity than the one of low-$p_{\rm T}$ electrons. The measurement in p$-$Pb collisions shows no $p_{\rm T}$ dependence within uncertainties. The self-normalised yields in pp and p$-$Pb collisions are compared with measurements of other heavy-flavour, light-flavour, and strange particles, and with Monte Carlo simulations