L. Zhu

Molecular spin valve and spin filter composed of single-molecule magnets

We presented a theoretical study on the spin-polarized transport of one single-molecule magnet. The results show it has spin filter behavior, and can also be used as a molecular spin valve with large abnormal magnetoresistance, which is an excellent candidate for spintronics of molecular devices. It is also found that the steplike features with negative differential resistance in the I-V curve indeed originate from the discreteness and narrow features in the density of states of the molecular levels.

Magnetic and electronic switching properties of photochromic diarylethene with two nitronyl nitroxides

Magnetic and electronic switching properties of single photochromic diarylethene with two nitronyl nitroxides sandwiched between two gold surfaces for closed and open configurations were investigated theoretically. Apart from the negative magnetoresistance effect in closed configuration, the negative differential resistance behavior in parallel state is also attained, which are potential for electronic applications. In addition, when using Br and H to substitute F atoms in the peripheral of cyclopentene, the on-off ratios are much smaller than that of the F-ligand one

Perfect spin filtering effect and negative differential behavior in phosphorus-doped zigzag graphene nanoribbons.

On the basis of the density functional theory combined with the Keldysh nonequilibrium Green’s function method, we investigate the spin-dependent transport properties of single-edge phosphorus-doped ZGNR systems with different widths. The results show a perfect spin filtering effect reaching 100% at a wide bias range in both parallel (P) and antiparallel (AP) spin configurations for all systems, especially for 6-ZGNR-P system. Instructively, for the AP spin configuration, the spin down current of the 4-ZGNR-P system exhibits a negative differential effect. By analyzing the transmission spectrum and the spin-resolved band structures of the electrodes, we elucidate the mechanism for these peculiar properties. Our findings provide a new way to produce multifunctional spintronic devices based on phosphorus-doped zigzag graphene nanoribbons.

The integrated spintronic functionalities of an individual high-spin state spin-crossover molecule between graphene nanoribbon electrodes

The spin-polarized transport properties of a high-spin-state spin-crossover molecular junction with zigzag-edge graphene nanoribbon electrodes have been studied using density functional theory combined with the nonequilibrium Greens-function formalism. The molecular junction presents integrated spintronic functionalities such as negative differential resistance behavior, spin filter and the spin rectifying effect, associated with the giant magnetoresistance effect by tuning the external magnetic field. Furthermore, the transport properties are almost unaffected by the electrode temperature. The microscopic mechanism of these functionalities is discussed. These results represent a step toward multifunctional molecular spintronic devices on the level of the individual spin-crossover molecule.

TNF-α stimulates endothelial palmitic acid transcytosis and promotes insulin resistance

Persistent elevation of plasma TNF-α is a marker of low grade systemic inflammation. Palmitic acid (PA) is the most abundant type of saturated fatty acid in human body. PA is bound with albumin in plasma and could not pass through endothelial barrier freely. Albumin-bound PA has to be transported across monolayer endothelial cells through intracellular transcytosis, but not intercellular diffusion. In the present study, we discovered that TNF-α might stimulate PA transcytosis across cardiac microvascular endothelial cells, which further impaired the insulin-stimulated glucose uptake by cardiomyocytes and promoted insulin resistance. In this process, TNF-α-stimulated endothelial autophagy and NF-κB signaling crosstalk with each other and orchestrate the whole event, ultimately result in increased expression of fatty acid transporter protein 4 (FATP4) in endothelial cells and mediate the increased PA transcytosis across microvascular endothelial cells. Hopefully the present study discovered a novel missing link between low grade systemic inflammation and insulin resistance.

Siglec-5 is a novel marker of critical limb ischemia in patients with diabetes

Critical Limb Ischemia (CLI) is common but uncommonly diagnosed. Improved recognition and early diagnostic markers for CLI are needed. Therefore, the aim of our study was to identify plasma biomarkers of CLI in patients with type 2 diabetes mellitus (T2DM). In this study, antibody-coated glass slide arrays were used to determine the plasma levels of 274 human cytokines in four matched cases of diabetes with and without CLI. Potential biomarkers were confirmed in an independent cohort by ELISA. After adjusting for confounding risk factors, only plasma level of Siglec-5 remained significantly associated with an increased odds ratio (OR) for diabetes with CLI by binary logistic regression analysis. Receiver operating characteristic (ROC) curve analysis revealed the optimal cut-off points for Siglec-5 was 153.1 ng/ml. After entering Siglec-5, the AUC was 0.99, which was higher than that of confounding risk factors only (AUC = 0.97, P < 0.05). Siglec-5 was expressed in plaques, but not in healthy artery wall in T2DM patients. Elevated plasma Siglec-5 was independently associated with CLI in T2DM. Plasma Siglec-5 levels are implicated as an early diagnostic marker of CLI in T2DM patients and it may become a target for the prevention or treatment of CLI in diabetes.

Spin-dependent thermoelectric effects in Fe-C 6 doped monolayer MoS 2

By using the non-equilibrium Green’s function with density functional theory, we have studied the thermal spin transport properties of Fe-C6 cluster doped monolayer MoS2. The results show that the device has a perfect Seebeck effect under temperature difference without gate voltage or bias voltage. Moreover, we also find the thermal colossal magnetoresistance effect, which is as high as 107%. The competition between spin up electrons and spin down holes of the parallel spin configuration leads to peculiar behavior of colossal magnetoresistance and thermo-current, which is essential for the design of thermal transistors. These results are useful in future MoS2-based multifunctional spin caloritronic devices.

The electronic structure and the ferromagnetic intermolecular interactions in the crystal of a diphenyl nitroxide derivative

Based on the generalized gradient approximation, full potential linearized augmented plane-wave calculations have been performed to study the electronic band structure and the ferromagnetic (FM) interactions of the 9,9-dipropyl-9,10-dihydroacridin-10-yloxyl (DPAO) organic radical. The total and partial density of states and the atomic spin magnetic moments are calculated and discussed. It is found that the unpaired electrons in this radical are localized in a molecular orbital constituted primarily of the π* (NO) orbital, and the main contribution of the spin magnetic moment comes from the NO free radical, with little contributions from other C atoms. The origin of FM interactions is also studied in detail.