72 research outputs found

    Mapping the unconventional orbital texture in topological crystalline insulators

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    The newly discovered topological crystalline insulators (TCIs) harbor a complex band structure involving multiple Dirac cones. These materials are potentially highly tunable by external electric field, temperature or strain and could find future applications in field-effect transistors, photodetectors, and nano-mechanical systems. Theoretically, it has been predicted that different Dirac cones, offset in energy and momentum-space, might harbor vastly different orbital character, a unique property which if experimentally realized, would present an ideal platform for accomplishing new spintronic devices. However, the orbital texture of the Dirac cones, which is of immense importance in determining a variety of materials properties, still remains elusive in TCIs. Here, we unveil the orbital texture in a prototypical TCI Pb1x_{1-x}Snx_xSe. By using Fourier-transform (FT) scanning tunneling spectroscopy (STS) we measure the interference patterns produced by the scattering of surface state electrons. We discover that the intensity and energy dependences of FTs show distinct characteristics, which can directly be attributed to orbital effects. Our experiments reveal the complex band topology involving two Lifshitz transitions and establish the orbital nature of the Dirac bands in this new class of topological materials, which could provide a different pathway towards future quantum applications

    Borehole-wall scanning for Mars research – testing the ExoMars 2020 rover’s work at Tabernas Desert

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    Overview of the borehole-wall scanning results from the ExoFIT field test of the ExoMars 2020 rover in Tabernas Desert, Spain

    A procedurális emlékezet szerepe a testkép zavaraiban = The role of procedural memory in trouble of body picture

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    Az evészavarok egyik vezető betegségfenntartó tényezője a betegek torzult, diszfunkcionális kogníciója. Ezen belül is kiemelendők a táplálékfelvételi viselkedés zavaraival és a testélménnyel kapcsolatban lévő, a zavarok létrejöttében kulcsszerepet játszó kognitív disztorziók, melyek az információfeldolgozási folyamatokon belül elsősorban a perceptuális élményfeldolgozást érintik és evészavaros betegeknél a testkép speciális zavarában mutatkoznak meg. A kognitív információfeldolgozást a sémák irányítják, amelyekben a selfről való komplex tudás szerveződik. A sémák procedurális ismeretanyagot is hordoznak, úgy mint motoros készségeket, szokásokat, szabályokat, célképzeteket, döntéshozatali stratégiákat. Ezek alapján felmerül, hogy az evészavarokra jellemző viselkedéses rutincselekvések, mint például a diétázás, falásroham, önhánytatás a testkép sémáján belül procedurális élményanyagként kódolódhat és a munkamemóriában automatikusan a többi explicit tudással és emlékkel együtt aktiválódik. Elméleti áttekintésünkben ezeknek a prekognitív folyamatoknak keressük a helyét és szerepét az evészavaros betegekre jellemző kognitív információfeldolgozási jellegzetességek kialakításában

    Gate-Tunable Transmon Using Selective-Area-Grown Superconductor-Semiconductor Hybrid Structures on Silicon

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    We present a gate-voltage tunable transmon qubit (gatemon) based on planar InAs nanowires that are selectively grown on a high resistivity silicon substrate using III-V buffer layers. We show that low loss superconducting resonators with an internal quality of 2×1052\times 10^5 can readily be realized using these substrates after the removal of buffer layers. We demonstrate coherent control and readout of a gatemon device with a relaxation time, T1700nsT_{1}\approx 700\,\mathrm{ns}, and dephasing times, T220nsT_2^{\ast}\approx 20\,\mathrm{ns} and T2,echo1.3μsT_{\mathrm{2,echo}} \approx 1.3\,\mathrm{\mu s}. Further, we infer a high junction transparency of 0.40.90.4 - 0.9 from an analysis of the qubit anharmonicity

    Casein kinase 2 phosphorylates and induces the SALL2 tumor suppressor degradation in colon cancer cells

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    Spalt-like proteins are Zinc finger transcription factors from Caenorhabditis elegans to vertebrates, with critical roles in development. In vertebrates, four paralogues have been identified (SALL1-4), and SALL2 is the family’s most dissimilar member. SALL2 is required during brain and eye development. It is downregulated in cancer and acts as a tumor suppressor, promoting cell cycle arrest and cell death. Despite its critical functions, information about SALL2 regulation is scarce. Public data indicate that SALL2 is ubiquitinated and phosphorylated in several residues along the protein, but the mechanisms, biological consequences, and enzymes responsible for these modifications remain unknown. Bioinformatic analyses identified several putative phosphorylation sites for Casein Kinase II (CK2) located within a highly conserved C-terminal PEST degradation motif of SALL2. CK2 is a serine/threonine kinase that promotes cell proliferation and survival and is often hyperactivated in cancer. We demonstrated that CK2 phosphorylates SALL2 residues S763, T778, S802, and S806 and promotes SALL2 degradation by the proteasome. Accordingly, pharmacological inhibition of CK2 with Silmitasertib (CX-4945) restored endogenous SALL2 protein levels in SALL2-deficient breast MDA-MB-231, lung H1299, and colon SW480 cancer cells. Silmitasertib induced a methuosis-like phenotype and cell death in SW480 cells. However, the phenotype was significantly attenuated in CRISPr/Cas9-mediated SALL2 knockout SW480 cells. Similarly, Sall2-deficient tumor organoids were more resistant to Silmitasertib-induced cell death, confirming that SALL2 sensitizes cancer cells to CK2 inhibition. We identified a novel CK2-dependent mechanism for SALL2 regulation and provided new insights into the interplay between these two proteins and their role in cell survival and proliferation

    Kama muta: conceptualizing and measuring the experience of being moved across 19 nations and 15 languages

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    English-speakers sometimes say that they feel moved to tears, emotionally touched, stirred, or that something warmed their heart; other languages use similar passive contact metaphors to refer to an affective state. We propose and measure the concept of kama muta to understand experiences often given these and other labels. Do the same experiences evoke the same kama muta emotion across nations and languages? We conducted studies in 19 different countries, five continents, 15 languages, with a total of 3542 participants. We tested the construct while validating a comprehensive scale to measure the appraisals, valence, bodily sensations, motivation, and lexical labels posited to characterize kama muta. Our results are congruent with theory and previous findings showing that kama muta is a distinct positive social relational emotion that is evoked by experiencing or observing a sudden intensification of communal sharing. It is commonly accompanied by a warm feeling in the chest, moist eyes or tears, chills or piloerection, feeling choked up or having a lump in the throat, buoyancy and exhilaration. It motivates affective devotion and moral commitment to communal sharing. While we observed some variations across cultures, these five facets of kama muta are highly correlated in every sample, supporting the validity of the construct and the measure.info:eu-repo/semantics/acceptedVersio

    Interaction of Rio1 Kinase with Toyocamycin Reveals a Conformational Switch That Controls Oligomeric State and Catalytic Activity

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    Rio1 kinase is an essential ribosome-processing factor required for proper maturation of 40 S ribosomal subunit. Although its structure is known, several questions regarding its functional remain to be addressed. We report that both Archaeoglobus fulgidus and human Rio1 bind more tightly to an adenosine analog, toyocamycin, than to ATP. Toyocamycin has antibiotic, antiviral and cytotoxic properties, and is known to inhibit ribosome biogenesis, specifically the maturation of 40 S. We determined the X-ray crystal structure of toyocamycin bound to Rio1 at 2.0 Å and demonstrated that toyocamycin binds in the ATP binding pocket of the protein. Despite this, measured steady state kinetics were inconsistent with strict competitive inhibition by toyocamycin. In analyzing this interaction, we discovered that Rio1 is capable of accessing multiple distinct oligomeric states and that toyocamycin may inhibit Rio1 by stabilizing a less catalytically active oligomer. We also present evidence of substrate inhibition by high concentrations of ATP for both archaeal and human Rio1. Oligomeric state studies show both proteins access a higher order oligomeric state in the presence of ATP. The study revealed that autophosphorylation by Rio1 reduces oligomer formation and promotes monomerization, resulting in the most active species. Taken together, these results suggest the activity of Rio1 may be modulated by regulating its oligomerization properties in a conserved mechanism, identifies the first ribosome processing target of toyocamycin and presents the first small molecule inhibitor of Rio1 kinase activity
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