Ferroelectricity with Asymmetric Hysteresis in Metallic LiOsO3 Ultrathin Films

Bulk LiOsO3 was experimentally identified as a "ferroelectric" metal where polar distortions coexist with metallicity [Shi et al., Nature Materials 12, 1024 (2013)]. It is generally believed that polar displacements in a "ferroelectric" metal cannot be switched by an external electric field. Here, via comprehensive density functional theory calculations, we demonstrate that a two-unit-cell-thick LiOsO3 thin film exhibits a ferroelectric ground state having an out-of-plane electric dipole moment that can be switched by an external electric field. Moreover, its dipole moment-versus-electric-field hysteresis loop is asymmetric because only surface Li ions'displacements are reversed by external electric field whereas the field-induced force on inner Li atoms are nearly fully screened by itinerant electrons. As a relevant by-product of our study, we also extend the concept of "Born effective charge" to finite metallic systems, and show its usefulness to rationalize the observed effects.Comment: 13 pages, 4 figure

Alcohol Promotes Mammary Tumor Growth through Activation of VEGF-Dependent Tumor Angiogenesis

Alcohol consumption has been recognized as a risk factor for breast cancer. Experimental studies demonstrate that alcohol exposure promotes the progression of existing mammary tumors. However, the mechanisms underlying this effect remain unclear. In the present study, the role of vascular endothelial growth factor (VEGF) in alcohol promotion of breast cancer development was investigated using a mouse xenograft model of mammary tumors and a three-dimensional (3D) tumor/endothelial cell co-culture system. For the mouse xenograft model, mouse E0771 breast cancer cells were implanted into the mammary fat pad of C57BL6 mice. These mice were exposed to alcohol in their drinking water. For the 3D co-culture system, E0771 cells and MDA-MB231 breast cancer cells were co-cultured with SVEC4-10EE2 and human umbilical vein endothelial cells, respectively. The results demonstrated that alcohol increased tumor angiogenesis and accelerated tumor growth. Furthermore, it appeared that alcohol induced VEGF expression in breast cancer cells in vitro and in vivo. Blocking VEGF signaling by SU5416 inhibited tumor angiogenesis in the 3D tumor/endothelial cell co-culture system. Furthermore, injection of SU5416 into mice inhibited alcohol-promoted mammary tumor growth in vivo. These results indicate that alcohol may promote mammary tumor growth by stimulating VEGF-dependent angiogenesis

Monitoring the Process of Endostar-Induced Tumor Vascular Normalization by Non-contrast Intravoxel Incoherent Motion Diffusion-Weighted MRI

Tumor vascular normalization has been proposed as a new concept in anti-tumor angiogenesis, and the normalization window is considered as an opportunity to increase the effect of chemoradiotherapy. However, there is still a lack of a non-invasive method for monitoring the process of tumor vascular normalization. Intravoxel incoherent motion diffusion-weighted magnetic resonance imaging (IVIM DW-MRI) is an emerging approach which can effectively assess microperfusion in tumors, without the need for exogenous contrast agents. However, its role in monitoring tumor vascular normalization still needs further study. In this study, we established a tumor vascular normalization model of CT26 colon-carcinoma-bearing mice by means of Endostar treatment. We then employed IVIM DW-MRI and immunofluorescence to detect the process of tumor vascular normalization at different times after treatment. We found that the D* values of the Endostar group were significantly higher than those of the control group on days 4, 6, 8, and 10 after treatment, and the f values of the Endostar group were significantly higher than those of the control group on days 6 and 8. Furthermore, we confirmed through analysis of histologic parameters that Endostar treatment induced the CT26 tumor vascular normalization window starting from day 4 after treatment, and this window lasted for 6 days. Moreover, we found that D* and f values were well correlated with pericyte coverage (r = 0.469 and 0.504, respectively; P < 0.001, both) and relative perfusion (r = 0.424 and 0.457, respectively; P < 0.001, both). Taken together, our findings suggest that IVIM DW-MRI has the potential to serve as a non-invasive approach for monitoring Endostar-induced tumor vascular normalization

As the tree is, so is the fruit? Examining the effects of ethical leadership on bootlegging from the perspective of leader–follower gender similarity

Purpose: The purpose of this study is to explore how and when ethical leadership enhances bootlegging. To achieve this purpose, the authors proposed a moderated dual-path model in this study. Design/methodology/approach: The model was tested on two related studies. Study 1 was based on three-wave, collected data from a sample of 511 employees of Chinese companies. Data used in Study 2 was collected by survey from employees and their direct leaders of multiple departments of companies in China. Findings: In Study 1, the authors found that moral efficacy and moral identity mediate between ethical leadership and bootlegging. Findings from Study 2 provide convergent support of moral efficacy’s and moral identity’s impact on the mediation relationship between ethical leadership and bootlegging. Moreover, the results of Study 2 further reveal that the relationship between ethical leadership and moral efficacy (or moral identity) was more significant among leader–follower with different genders. Originality/value: This study not only enriches the literature on ethical leadership and gender (dis)similarity, but also helps managers to better understand the function of bootlegging

Ambidextrous leadership and radical innovative capability: The moderating role of leader support

Radical innovation is a fundamental approach to achieving sustainable and competitive advantage. However, existing studies have not adequately explored the antecedents of radical innovation; in particular, consideration of leadership factors in a Chinese context is lacking. Ambidextrous leadership provides a new perspective for explaining radical innovation. In this study, we developed a moderation model and tested it with three-wave data of 511 employees from the Chinese mainland, linking ambidextrous leadership with radical innovative capability. The results support our hypotheses that high-empowering–low-directive leadership (punctuated ambidextrous leadership) is more beneficial for radical innovation, and strong leader support can strengthen this effect. However, our hypothesis that simultaneous ambidextrous leadership influences positively radical innovation capability was not supported. These findings indicate that leaders should change their original conservative and directive strategies to enhance radical innovative capability

The impact of ability-, motivation- and opportunity-enhancing strategic human resource management on performance: the mediating roles of emotional capability and intellectual capital

We used data from 441 managers of science and technology enterprises to empirically test the dynamic capability path and resource-based path of ability-enhancing, motivation-enhancing and opportunity-enhancing (AMO) strategic human resource management as influencing factors on performance. The results show that AMO-enhancing strategic human resource management affects organizational performance through organizational emotional capability and organizational intellectual capital in the start-up stage. In the development stage, ability- and opportunity-enhancing strategic human resource management affects performance through organizational emotional capability and organizational intellectual capital, while motivation-enhancing strategic human resource management has no significant impact on performance. In the mature stage, ability-enhancing strategic human resource management influences performance through organizational emotional capability, while motivation- and opportunity-enhancing strategic human resource management has no significant effect on performance

Shape Memory-Enhanced Electrical Self-Healing of Stretchable Electrodes

A novel shape memory-based self-healable stretchable electrode was explored by embedding the silver nanowires (AgNWs) network into a healable polymer matrix. Unlike the traditional shape memory-assisted self-healing, pre-stretching to the temporary shapes, which was fixed in a typical shape, memory thermo-mechanical programming significantly enhanced the thermo-triggered healing performance. The morphological as well as conduction variations during the healing process were investigated. The enhancing effect of the pre-stretching on the healing efficiency was emphasized, which was expected to attribute to the release of the pre-stored strain energy driving the closure of the scratch. The findings disclosed how to utilize the shape memory effect to improve the biomimetic properties for the stretchable electrodes, which may greatly benefit the application of the intelligent polymers in the field of multi-functional flexible electronics

Fabric Coated with Shape Memory Polyurethane and Its Properties

In order to provide thermo-physiological comfort to the wearer, textile materials should have some functional property like water-resistance or water vapor transmission (WVT), so that perspiration can evaporate and be transmitted from the body surface to the environment even in extreme weather conditions that require wind and rain proof. Shape memory polyurethane (SMPU) could possibly be a candidate; it is a functional textile material that meets such requirements. In this research, we synthesized a series of SMPUs, which are responsive materials, to test whether these coated cotton fabrics could provide thermal insulation with lower permeability at low temperature or low relative humidity (RH), and high permeability at room temperature or above, or high relative humidity with its water-resistance property. In this paper, we have proposed a segmented shape memory polyurethane for coated textiles in order to have a water-resistant textile with good water vapor transmitting ability