Magneto-Optical Imaging of Magnetic-Domain Pinning Induced by Chiral Molecules

Chiral molecules have the potential for creating new magnetic devices by locally manipulating the magnetic properties of metallic surfaces. When chiral polypeptides chemisorb onto ferromagnets they can induce magnetization locally by spin exchange interactions. However, direct imaging of surface magnetization changes induced by chiral molecules was not previously realized. Here, we use Magneto-optical Kerr microscopy to image domains in thin films and show that chiral polypeptides strongly pin domains, increasing the coercive field locally. In our study, we also observe a rotation of the easy magnetic axis towards the out-of-plane, depending on the sample's domain size and the adsorption area. These findings show the potential of chiral molecules to control and manipulate magnetization and open new avenues for future research on the relationship between chirality and magnetization.Comment: 11 pages, 4 figure

Chirality-Induced Magnetization of Magnetite by an RNA Precursor

Life is homochiral and homochirality is a fundamental feature of living systems on Earth. While the exact mechanism that led to homochirality is still not fully understood, any realistic scenario on the origins of life needs to address the emergence of homochirality. In order to impose and maintain chirality in a prebiotic network, an environmental factor functioning as a chiral agent is demanded. Magnetized surfaces are prebiotically plausible chiral agents, shown to be effective in enantioseparation of ribose-aminooxazoline (RAO), a ribonucleic acid (RNA) precursor, due to the chiral-induced spin selectivity (CISS) effect. As such, mechanisms for breaking the magnetic symmetry of magnetic minerals are of the utmost importance. Here we report the avalanche magnetization of magnetite $(Fe_{3}O_{4})$ by the crystallization of enantiopure RAO. The observed breaking of the magnetic symmetry is induced by the chiral molecules due to the CISS effect and spreads out across the magnetic surface like an avalanche, providing a way to uniformly magnetize a magnetic surface without fully covering it. Considered together with our previous results on enantioseparation by crystallization on a magnetic surface, chirality-induced avalanche magnetization paves the way for a cooperative feedback between chiral molecules and magnetic surfaces. With this feedback, a weak natural bias in the net magnetization can be amplified and spin-selective processes can be accommodated on magnetic minerals on a persistent basis.Comment: 19 pages, 6 figure

Macrophage-Induced Lymphangiogenesis and Metastasis following Paclitaxel Chemotherapy Is Regulated by VEGFR3

While chemotherapy strongly restricts or reverses tumor growth, the response of host tissue to therapy can counteract its anti-tumor activity by promoting tumor re-growth and/or metastases, thus limiting therapeutic efficacy. Here, we show that vascular endothelial growth factor receptor 3 (VEGFR3)-expressing macrophages infiltrating chemotherapy-treated tumors play a significant role in metastasis. They do so in part by inducing lymphangiogenesis as a result of cathepsin release, leading to VEGF-C upregulation by heparanase. We found that macrophages from chemotherapy-treated mice are sufficient to trigger lymphatic vessel activity and structure in naive tumors in a VEGFR3-dependent manner. Blocking VEGF-C/VEGFR3 axis inhibits the activity of chemotherapy-educated macrophages, leading to reduced lymphangiogenesis in treated tumors. Overall, our results suggest that disrupting the VEGF-C/VEGFR3 axis not only directly inhibits lymphangiogenesis but also blocks the pro-metastatic activity of macrophages in chemotherapy-treated mice

Dissociation and Suicidality in Eating Disorders: The Mediating Function of Body Image Disturbances, and the Moderating Role of Depression and Anxiety

In patients with eating disorders (EDs), elevated dissociation may increase the risk of suicide. Bodily related disturbances, depression, and anxiety may intervene in the association between dissociation and suicidality. In this study we aimed to examine the influence of bodily related disturbances, depression, anxiety, severity of ED symptoms, body mass index (BMI), and type and duration of the ED on the relationship between elevated dissociation and elevated suicidality. The study included 172 inpatients: 65 with anorexia nervosa restricting type, 60 with anorexia nervosa binge/purge type, and 37 with bulimia nervosa. Participants were assessed using self-rating questionnaires for dissociation, suicidality, bodily related parameters, and severity of ED symptomatology, depression, and anxiety. We found that dissociation and suicidality were directly associated. In addition, depression and anxiety moderated the mediating role of body image parameters in the association between increased dissociation and increased suicidality. Thus, only in inpatients with high depression and anxiety, i.e., above the median range, body image disturbances were found to mediate the association between dissociation and suicidality. ED-related parameters did not moderate these relationships. Our study demonstrates that in inpatients with EDs, increased dissociation may be significantly associated with increased suicidality, both directly and via the intervening influence of body image, depression, and anxiety

Data for Chiral-induced unidirectional spin-to-charge conversion

<p>Raw data and analyzed data to generate the figures of our article.</p&gt