Malignant Interaction between B Cells and T Helper Cells

Collaboration of T helper (Th) cells with B cells is central for the generation of high-affinity antibodies with distinct effector function and thus for the establishment of effective immune responses. Physiological T cell help for B cells takes place in germinal centers (GC) in peripheral lymphoid organs, where follicular T helper (Tfh) cells interact with mature, antigen-stimulated B cells. Occasionally, B cells undergo malignant transformation, which may lead to the development of leukemia or lymphoma. Over the past decades, it has become increasingly clear that cancer cells depend on interactions with the tumor microenvironment for growth and survival. Since many B cell malignancies develop in GC—the place of physiological Th cell-B cell interaction—Th cells are a central part of the tumor microenvironment of B cell leukemia and lymphoma. Thus, while the interaction between Th cells and normal B cells is crucial for the development of an effective immune response, this interaction also contributes to the development and pathogenesis of malignancies. The present chapter discusses the mechanisms underlying Th cell-mediated support of malignant B cells contributing to the pathogenesis of leukemia and lymphoma. Research efforts aiming to elucidate such mechanisms are of high importance as therapeutic targeting of these malignant interactions may increase treatment efficiency and reduce disease relapse

Metacognition and Self-Control: An Integrative Framework

Self-control describes the processes by which individuals control their habits, desires, and impulses in the service of long-term goals. Research has identified important components of self-control and proposed theoretical frameworks integrating these components (e.g., Inzlicht et al., 2021; Kotabe & Hofmann, 2015). In our perspective, these frameworks, however, do not yet fully incorporate important metacognitive aspects of self-control. We therefore introduce a framework explicating the role of metacognition for self-control. This framework extends existing frameworks, primarily from the domains of self-regulated learning and problem-solving (e.g., Schraw & Moshman, 1995; Zimmermann, 2000), and integrates past and contemporary research and theorizing on self-control that involves aspects of metacognition. It considers two groups of metacognitive components, namely (1) individual metacognitive characteristics, that is a person´s declarative, procedural, and conditional metacognitive knowledge about self-control, as well as their self-awareness (or metacognitive awareness), and (2) metacognitive regulatory processes that unfold before a self-control conflict (forethought, and prevention), when a self-control conflict is identified, during a self-control conflict (regulation and monitoring), and after a self-control conflict (reflection and evaluation). The proposed framework integrates existing research and will be useful for highlighting new directions for research on the role of metacognition for self-control success and failure

Observation of Josephson coupling through an interlayer of antiferromagnetically ordered chromium

The supercurrent transport in metallic Josephson tunnel junctions with an additional interlayer made up by chromium, being an itinerant antiferromagnet, was studied. Uniform Josephson coupling was observed as a function of the magnetic field. The supercurrent shows a weak dependence on the interlayer thickness for thin chromium layers and decays exponentially for thicker films. The diffusion constant and the coherence length in the antiferromagnet were estimated. The antiferromagnetic state of the barrier was indirectly verified using reference samples. Our results are compared to macroscopic and microscopic models.Comment: Phys. Rev. B (2009), in prin

Spin-Transfer Torque Induced Vortex Dynamics in Fe/Ag/Fe Nanopillars

We report experimental and analytical work on spin-transfer torque induced vortex dynamics in metallic nanopillars with in-plane magnetized layers. We study nanopillars with a diameter of 150 nm, containing two Fe layers with a thickness of 15 nm and 30 nm respectively, separated by a 6 nm Ag spacer. The sample geometry is such that it allows for the formation of magnetic vortices in the Fe disks. As confirmed by micromagnetic simulations, we are able to prepare states where one magnetic layer is homogeneously magnetized while the other contains a vortex. We experimentally show that in this configuration spin-transfer torque can excite vortex dynamics and analyze their dependence on a magnetic field applied in the sample plane. The center of gyration is continuously dislocated from the disk center, and the potential changes its shape with field strength. The latter is reflected in the field dependence of the excitation frequency. In the second part we propose a novel mechanism for the excitation of the gyrotropic mode in nanopillars with a perfectly homogeneously magnetized in-plane polarizing layer. We analytically show that in this configuration the vortex can absorb energy from the spin-polarized electric current if the angular spin-transfer efficiency function is asymmetric. This effect is supported by micromagnetic simulations.Comment: The article has been sent to J. Phys. D. Submitted on August 9, 2010. (7 pages and 4 figures.

Thickness dependence of linear and quadratic magneto-optical Kerr effect in ultrathin Fe(001) films

Magneto-optical Kerr effect (MOKE) magnetometry is one of the most widely employed techniques for the characterization of ferromagnetic thin-film samples. Some information, such as coercive fields or anisotropy strengths can be obtained without any knowledge of the optical and magneto-optical (MO) properties of the material. On the other hand, a quantitative analysis, which requires a precise knowledge of the material's index of refraction n and the MO coupling constants K and G is often desirable, for instance for the comparison of samples, which are different with respect to ferromagnetic layer thicknesses, substrates, or capping layers. While the values of the parameters n and the linear MO coupling parameter K reported by different authors usually vary considerably, the relevant quadratic MO coupling parameters G of Fe are completely unknown. Here, we report on measurements of the thickness dependence (0-60nm) of the linear and quadratic MOKE in epitaxial bcc-Fe(001) wedge-type samples performed at a commonly used laser wavelength of 670nm. By fitting the thickness dependence we are able to extract a complete set of parameters n, K, (G11 - G12), and G44 for the quantitative description of the MOKE of bcc-Fe(001). We find sizable different n, K, and G parameters for films thinner than about 10nm as compared to thicker films, which is indicative of a thickness dependence of the electronic properties or of surface contributions to the MOKE. The effect size of the quadratic MOKE is found to be about a third of the record values recently reported for Co2FeSi.Comment: 8 pages, 5 figure

The Metacognition in Self-Control Scale (MISCS)

Metacognition is a well-researched construct important to successful learning. Recent studies show that state-level metacognition regarding self-control conflicts is also important for successfully resolving these conflicts. Because there exists no scale to assess trait-level metacognition in self-control and because of limitations of commonly used measures in self-control research, we adapted a scale that is widely used to assess trait-level metacognition in self-regulated learning, the Metacognitive Awareness Inventory (MAI). In two studies (N = 315 and N = 503), we constructed the 12-item Metacognition in Self-Control Scale (MISCS), which loaded on the two factors metacognitive knowledge and metacognitive regulation. The MISCS showed a good fit with good internal consistencies. In the 10-day experience sampling part of study 2, which included 9639 reports of self-control conflicts, higher trait-levels of metacognition as measured with the MISCS predicted higher state-levels of success in resolving these conflicts, as well as higher state-levels of the subcomponents of metacognition, namely metacognitive knowledge, planning, monitoring, and evaluation. Most of these associations persisted when controlling for trait self-control, supporting the usefulness of the scale beyond the most commonly used scale in self-control research. The MISCS showed adequate test-retest reliability. Correlations with other scales, limitations, and future directions are discussed

Enhanced Power Sources Compatible With Extended Thermal Environment

Today the race to lower the cost to orbit is stronger than ever, with the arrival of new competitors like Space-X. A way to lighten European next generation launchers (Ariane 6) is to use novel primary and secondary batteries for powering avionics, pyro systems, guidance and control electronics, as well as communication systems. Such application requires unrestricted operations at low temperature (−20°C) and safety behaviour at high temperature (70°C), in addition to a low self-discharge rate because most of the life time of the power source goes by under storage prior to launch. Several battery technologies could be used for this application. While the major challenge for Lithium primary cells is the power capability, regarding secondary Li-ion batteries it may be self-discharge. Both technologies will need a good low temperature power rate capability. CEA developed 18650 Li-ion cells and AA Li-CFx cells in order to tackle those particular challenges

Antiferromagnetic interlayer exchange coupling across an amorphous metallic spacer layer

By means of magneto-optical Kerr effect we observe for the first time antiferromagnetic coupling between ferromagnetic layers across an amorphous metallic spacer layer. Biquadratic coupling occurs at the transition from a ferromagnetically to an antiferromagnetically coupled region. Scanning tunneling microscopy images of all involved layers are used to extract thickness fluctuations and to verify the amorphous state of the spacer. The observed antiferromagnetic coupling behavior is explained by RKKY interaction taking into account the amorphous structure of the spacer material.Comment: Typset using RevTex, 4 pages with 4 figures (.eps