Van der Waals Magnetic Electrode Transfer for Two-Dimensional Spintronic Devices.

Two-dimensional (2D) materials are promising candidates for spintronic applications. Maintaining their atomically smooth interfaces during integration of ferromagnetic (FM) electrodes is crucial since conventional metal deposition tends to induce defects at the interfaces. Meanwhile, the difficulties in picking up FM metals with strong adhesion and in achieving conductance match between FM electrodes and spin transport channels make it challenging to fabricate high-quality 2D spintronic devices using metal transfer techniques. Here, we report a solvent-free magnetic electrode transfer technique that employs a graphene layer to assist in the transfer of FM metals. It also serves as part of the FM electrode after transfer for optimizing spin injection, which enables the realization of spin valves with excellent performance based on various 2D materials. In addition to two-terminal devices, we demonstrate that the technique is applicable for four-terminal spin valves with nonlocal geometry. Our results provide a promising future of realizing 2D spintronic applications using the developed magnetic electrode transfer technique.

Photon-Dipole-Spin Interactions in M(TCNE)x/P(VDF-TrFE) Multiferroic Heterostructure Available for Bimodal Control of Multistate Data-Storage.

Organic multiferroic heterostructure is one of the most promising structures for the future design of high-density flexible energy-efficient data storage. Here, organic ferromagnetic metal(tetracyanoethylene) (M(TCNE))x/ferroelectric poly(vinylidene fluoride-co-trifluoroethylene) (P(VDF-TrFE)) multiferroic heterostructures are fabricated, where the excited state in M(TCNE)x interacted with localized dipole in P(VDF-TrFE) provides a key link for the interfacial coupling. Thus, aligned dipoles in P(VDF-TrFE) by external electric field can affect the magnetization of Fe(TCNE)x effectively to result in a pronounced magnetization-voltage (M-V) hysteresis loop. Moreover, light-induced electron-hole pairs in Fe(TCNE)x with long lifetime effectively interact with the dipoles in P(VDF-TrFE) to lead to an effect in external light control of electric polarization of P(VDF-TrFE). Overall, the organic multiferroic heterostructure provides the possibility of realizing two storage modes, light control of dipole as well as electric field control of spin, which can broaden multifunctional applications of organic multiferroic materials in the area of multistate storage.

Strain-restricted transfer of ferromagnetic electrodes for constructing reproducibly superior-quality spintronic devices.

Spintronic device is the fundamental platform for spin-related academic and practical studies. However, conventional techniques with energetic deposition or boorish transfer of ferromagnetic metal inevitably introduce uncontrollable damage and undesired contamination in various spin-transport-channel materials, leading to partially attenuated and widely distributed spintronic device performances. These issues will eventually confuse the conclusions of academic studies and limit the practical applications of spintronics. Here we propose a polymer-assistant strain-restricted transfer technique that allows perfectly transferring the pre-patterned ferromagnetic electrodes onto channel materials without any damage and change on the properties of magnetism, interface, and channel. This technique is found productive for pursuing superior-quality spintronic devices with high controllability and reproducibility. It can also apply to various-kind (organic, inorganic, organic-inorganic hybrid, or carbon-based) and diverse-morphology (smooth, rough, even discontinuous) channel materials. This technique can be very useful for reliable device construction and will facilitate the technological transition of spintronic study.

Thermally Induced Persistent Covalent-Organic Frameworks Radicals.

Persistent covalent-organic framework (COF) radicals hold important applications in magnetics and spintronics; however, their facile synthesis remains a daunting challenge. Here, three p-phenylenediacetonitrile-based COFs (named CityU-4, CityU-5, and CityU-6) were synthesized. Upon heat treatment (250 °C for CityU-4 and CityU-5 or 220 °C for CityU-6), these frameworks were brought into their persistent radical forms (no obvious changes after at least one year), together with several observable factors, including color changes, red-shifted absorption, the appearance of electron spin resonance (ESR) signals, and detectable magnetic susceptibility. The theoretical simulation suggests that after heat treatment, lower total energy and nonzero spin density are two main factors to guarantee persistent COFs radicals and polarized spin distributions. This work provides an efficient method for the preparation of persistent COF radicals with promising potentials.

Magneto-responsive optics in a chiral crystal with thermally triggered reversible phase transitions between chiral space groups.

Herein, a chiral charge transfer crystal that exhibits reversible phase transition between chiral space groups has been fabricated. When the phase switches from left-handed to right-handed chiral space group, more pronounced orbital angular momentum effects will be generated, where magneto-responsive optics are the opposite for chiral enantiomers. Moreover, circularly polarized light could enhance the chiral orbit of the crystal with the same spiral orientation to let spin have a better ability to resist external magnetic field. Thus, the magnetic field dependence of transmission and photoluminescence of chiral crystals are strongly dependent on the polarized state of incident light. Furthermore, by studying the coupling among spin, orbit, and circular photon, we obtained that the chiral orbit plays a key role in the coupling between the spin and circular photon. It is expected that this work could promote further exploration of organic chiral magneto-optical crystals in potential applications of sensing.

Revealing the key role of molecular packing on interface spin polarization at two-dimensional limit in spintronic devices.

Understanding spinterfaces between magnetic metals and organic semiconductors is essential to unlock the great potentials that organic materials host for spintronic applications. Although plenty of efforts have been devoted to studying organic spintronic devices, exploring the role of metal/molecule spinterfaces at two-dimensional limit remains challenging because of excessive disorders and traps at the interfaces. Here, we demonstrate atomically smooth metal/molecule interfaces through nondestructively transferring magnetic electrodes on epitaxial grown single-crystalline layered organic films. Using such high-quality interfaces, we investigate spin injection of spin-valve devices based on organic films of different layers, in which molecules are packed in different manners. We find that the measured magnetoresistance and the estimated spin polarization increase markedly for bilayer devices compared with their monolayer counterparts. These observations reveal the key role of molecular packing on spin polarization, which is supported by density functional theory calculations. Our findings provide promising routes toward designing spinterfaces for organic spintronic devices.

An Organic Chiroptical Detector Favoring Circularly Polarized Light Detection from Near-Infrared to Ultraviolet and Magnetic-Field-Amplifying Dissymmetry in Detectivity.

Circularly polarized light detection has attracted growing attention because of its unique application in security surveillance and quantum optics. Here, through designing a chiral polymer as a donor, a high-performance circularly polarized light detector is fabricated, successfully enabling detection from ultraviolet (300 nm) to near-infrared (1100 nm). The chiroptical detector presents an excellent ability to distinguish right-handed and left-handed circularly polarized light, where dissymmetries in detectivity, responsivity, and electric current are obtained and then optimized. The dissymmetry in electric current can be increased from 0.18 to 0.23 once an external magnetic field is applied. This is a very rare report on the dissymmetry tunability by an external field in chiroptical detectors. Moreover, the chirality-generated orbital angular momentum is one of the key factors determining the performance of the circularly polarized light detection. Overall, the organic chiroptical detector presents excellent stability in detection, which provides great potential for future flexible and compact integrated platforms.

Identification and transfer of a new Pm21 haplotype with high genetic diversity and a special molecular resistance mechanism.

KEY MESSAGE: A new functional Pm21 haplotype, Pm21(8#), was cloned from the new wheat-H. villosa translocation line T6VS(8#)·6DL, which confers the same strong resistance to powdery mildew through a different resistance mechanism. Broad-spectrum disease resistance genes are desirable in crop breeding for conferring stable, durable resistance in field production. Pm21(4#) is a gene introduced from wild Haynaldia villosa into wheat that confers broad-spectrum resistance to wheat powdery mildew and has been widely used in wheat production for approximately 30 years. The discovery and transfer of new functional haplotypes of Pm21 into wheat will expand its genetic diversity in production and avoid the breakdown of resistance conferred by a single gene on a large scale. Pm21(4#) previously found from T6VS(4#)·6AL has been cloned. In this study, a new wheat-H. villosa translocation, T6VS(8#)·6DL, was identified. A new functional Pm21 haplotype, designated Pm21(8#), was cloned and characterized. The genomic structures and the splicing patterns of Pm21(4#) and Pm21(8#) were different, and widespread sequence diversity was observed in the gene coding region and the promoter region. In the field, Pm21(8#) conferred resistance to Blumeria graminis f. sp. tritici (Bgt), similar to Pm21(4#), indicating that Pm21(8#) was also a resistance gene. However, Bgt development during the infection stage was obviously different between Pm21(4#)- and Pm21(8#)-containing materials under the microscopic observation. Pm21(4#) inhibited the formation of haustoria and the development of hyphae in the initial infection stage, while Pm21(8#) limited the growth of hyphae and inhibited the formation of conidiophores in the late infection stage. Therefore, Pm21(8#) is a new functional Pm21 haplotype that provides a new gene resource for wheat breeding.

Dimerization Triggered Magnetoelectric Coupling Effect and Magnetic Anisotropy in Organic Ternary Crystals.

Developing a new universal strategy to design all organic ferromagnets or multiferroics with satisfactory properties always remains challenging. In this work, ternary charge transfer crystals are fabricated to realize organic multiferroic magnetoelectric coupling effect. Through incorporating the third component into binary crystals, a dimerization between neighbor donor and acceptor is induced to form a lattice symmetry breaking, where a nonpolar to polar phase transition is ensuing to lead to a dipolar polarization. Magnetic field can effectively tune the dipolar polarization to present a magnetoelectric coupling effect. Moreover, the introduction of the third component can result in a rearrangement in molecular configuration to modify the electron-phonon interaction. As a result, anisotropic magnetism is observed due to anisotropic electron-phonon coupling in ternary crystals. Overall, this study forecasts that incorporating an appropriate third component is a potential method for designing all organic multiferroics.

Schottky diodes based on blue phosphorene nanoribbon homojunctions.

Diodes have been widely studied as one of the most commonly used electronic components in circuits, and it is important to find diodes with an excellent rectification performance. Herein, we investigate the electronic and transport properties of Schottky contact diodes based on zigzag hydrogenated blue phosphorene nanoribbons, by employing density functional theory combined with the non-equilibrium Green's function. It is found that the adsorption of transition metal atoms Sc/Cr/Ti and Ni on the top site of blue phosphorene nanoribbons leads to metallic and semiconducting properties, respectively. Devices consisting of the planar contact of the metallic and semiconducting nanoribbons show rectifying behavior due to the Schottky barriers of the homojunctions. The current is preferential to flow from the semiconducting side to the metallic side. The rectification ratio of the Sc-Ni device and the Cr-Ni device can reach up to 108, which is much higher than that of traditional p-n junctions of about 105-107. The high rectification ratio at low bias regions, together with the low threshold voltages and negligible reverse currents, make blue phosphorene nanoribbon homojunctions ideal rectifier diodes.

Response of Spin to Chiral Orbit and Phonon in Organic Chiral Ferrimagnetic Crystals.

Achiral organic materials show nearly negligible orbit angular momentum, whereas organic ferrimagnets with chirality and reduced electron-lattice scattering could fundamentally bridge the gap between ferromagnetism and antiferromagnetism in the rapidly emerging field of ferrimagnetic spintronics. In this work, we report enantiomeric organic chiral ferrimagnets, where the chirality results from the molecular torsion by propeller-like arrangement of the donor and acceptor molecules. The ferrimagnetism results from the difference in electron-phonon coupling of the donor and acceptor inside the chiral crystals. Because the spin polarization is significantly dependent on the chirality, the magnetization of right-handed organic chiral ferrimagnetic crystals is larger than that of left-handed ones by 300% at 10 K. In addition, the processes of both excitation and recombination are strongly related to spin, phonon, and chiral orbit in these chiral ferrimagnets. Overall, both the organic chiral ferrimagnetism and spin chiroptical activities may substantially enrich the field of organic spintronics.

Mechanoresponsive Spin via Spin-Lattice Coupling in Organic Cocrystals.

The response of crystal structure to external stimuli provides potential applications in the areas of detection, diagnosis, and repair. In this work, we fabricate two allotropic organic cocrystals, with different space groups and lattice parameters, with identical donor and acceptor molecules inside them. Under external stimuli, lattice vibration and electron-phonon coupling present pronounced differences in these two types of crystals, where different strengths of spin polarizations are observed. Furthermore, due to pronounced differences in coupling between lattice and spin inside the allotropic charge transfer crystals, the magnetic field presents a discrepant tunability on both transmission and fluorescence lifetimes. Through decreasing temperature or applying external electric field, the electron-phonon coupling coefficient presents a decreasing tendency, which will affect the dipole and dielectric constant in the allotropic crystals differently.

Egr­1 inhibits colon cancer cell proliferation, migration and invasion via regulating CDKL1 at the transcriptional level.

Colon cancer is one of the most common malignant tumors worldwide, and the molecular mechanisms involved in the oncogenesis and progression of colon cancer remain unclear. Early growth response 1 (Egr­1) is a transcription factor that is closely associated with several tumor processes; however, its role in colon cancer is unknown. The present study aimed to explore the function and mechanism of transcription factor Egr­1 in colon cancer progression. The association between Egr­1 expression and the survival of patients with colon cancer was analyzed. Transwell assay was used to measure the migration and invasion of colon cancer cells. Cell Counting Kit­8 assay was used to evaluate the cell proliferative ability. Reverse transcription­quantitative PCR and western blot assays were used to identify whether Egr­1 could regulate cyclin­dependent kinase­like 1 (CDKL1). Luciferase and chromatin immunoprecipitation assays were used to detect the mechanism by which Egr­1 regulated CDKL1. Based on The Cancer Genome Atlas database, it was found that low Egr­1 expression was associated with a poor prognosis in patients with colon cancer. Furthermore, overexpression of Egr­1 inhibited colon cancer cell proliferation, migration, and invasion, whereas knockdown of Egr­1 increased colon cancer cell proliferation, migration and invasion. Additionally, overexpression of Egr­1­induced cell proliferation, migration and invasion were reversed by overexpression of CDKL1. Furthermore, it was demonstrated that Egr­1 regulated CDKL1 expression at the transcriptional level. The present study illustrated the mechanism of Egr­1 regulating CDKL1, by which Egr­1 affected colon cancer cell proliferation, migration and invasion. The current findings suggested that Egr­1/CDKL1 may be a new promising target for the treatment of colon cancer.

Efficacy and safety of ramucirumab treatment in patients with advanced colorectal cancer: A protocol for systematic review and meta analysis.

BACKGROUND: vascular endothelial growth factor receptor 2 (VEGFR-2) has an important role in colorectal cancer pathogenesis and progression. The aim of our study is to provide a protocol for assessing the efficacy and safety of ramucirumab (a monoclonal antibody VEGFR-2 antagonist) for the treatment of advanced colorectal cancer. METHODS: The systematic review will be reported according to the preferred reporting items for systematic reviews and meta-analyses protocols. Relevant randomized controlled trials were searched from PubMed, Cochrane Library, Web of Science, Excerpt Medica Database, China National Knowledge Infrastructure, and Wanfang Database. Papers in English or Chinese published from their inception to February 2020 will be included without any restrictions.Study selection and data extraction will be performed independently by 2 investigators. The clinical outcomes including overall response rate, complete response rate (disease control rate), overall survival, progression-free survival, quality of life, immune function, and adverse events, were systematically evaluated. Review Manager 5.3 and Stata 14.0 were used for data analysis, and a fixed or random-effect model of meta-analysis will be used depending upon the heterogeneity observed between studies. Subgroup analysis will be carried out depending on the availability of sufficient clinical data. RESULTS AND CONCLUSION: The findings of this systematic review and meta-analysis will be published in a peer-reviewed journal, and provide more evidence-based guidance in clinical practice. PROSPERO REGISTRATION NUMBER: CRD42020165683.

Modulating the electronic structures of blue phosphorene towards spintronics.

Modulation of the electronic and magnetic structure of blue phosphorene nanoribbons to explore the potential application in spintronics is appealing. Using density functional theory in combination with the non-equilibrium Green's function method, the energetic, electronic, magnetic, and spin-resolved transport properties of hydrogenated armchair and zigzag blue phosphorene nanoribbons with surface modification by 3d transition metal atoms (ranging from Sc to Ni) were systematically investigated. The blue phosphorene nanoribbons were found to be highly capable of adsorbing impurity atoms, and the adatoms prefer a 2D growth mode on the nanoribbons. The band structures of the blue phosphorene nanoribbons were effectively modulated by the adatoms: the bandgap dramatically decreased with remarkable spin-polarization, except in the case of Ni. The spin-resolved transport properties of Sc-adsorbed zigzag blue phosphorene nanoribbons were selectively investigated to explore the potential application in spintronics, and a giant magnetoresistance effect of above 500 was found. This work suggests that the surface adsorption of 3d transition metal heteroatoms is a feasible and effective approach to functionalize blue phosphorene nanoribbons for spintronic applications.

[Relationship among breast cancer and negative life event and cell immunity].

OBJECTIVE: To investigate the relationship among breast cancer and negative life event and cell immunity. METHODS: A questionnaire survey using the Life Event by YANG Desen to investigate the family life problems, work problems, and social and other problems was conducted among 115 patients with breast cancer diagnosed by pathology and cytology and 115 gender, age, profession, education, and life habit-matched patients with benign breast diseases as controls. Fasting blood was drawn from all patients. Fluorescent-labeled bodies were added. Flow cytometry was made to count the immunocytes. RESULTS: The negative life event rate was 87% in the breast cancer group, higher than that in the control group (55%, P < 0.01). The rate of family problems in the breast cancer group was 63%, higher than that in the control group (40%). The total score of negative events was 31.5 +/- 9.7 in the breast cancer group, higher than that in the control group (17.3 +/- 5.6, P < 0.01). The percentage of CD(3) (total T cell) in the breast cancer group was 58.8 +/- 12.2%, significantly lower than that in the control group (63.9 +/- 9.9%, P < 0.01). There was no difference in the percentages of CD(4), CD(8), CD(4)/CD(8), and the percentage of natural killer cells (NK) between the two groups. CONCLUSION: Breast cancer is closely correlated with negative life events, especially family problems concerning marriage and children. The negative life events are related to the decrease of total T cells, and unrelated to the percentages of other cells.