Manipulation of electronic and magnetic properties of M2_2C (M=Hf, Nb, Sc, Ta, Ti, V, Zr) monolayer by applying mechanical strains

Tuning the electronic and magnetic properties of a material through strain engineering is an effective strategy to enhance the performance of electronic and spintronic devices. Recently synthesized two-dimensional transition metal carbides M$_2$C (M=Hf, Nb, Sc, Ta, Ti, V, Zr), known as MXenes, has aroused increasingly attentions in nanoelectronic technology due to their unusual properties. In this paper, first-principles calculations based on density functional theory are carried out to investigate the electronic and magnetic properties of M$_2$C subjected to biaxial symmetric mechanical strains. At the strain-free state, all these MXenes exhibit no spontaneous magnetism except for Ti$_2$C and Zr$_2$C which show a magnetic moment of 1.92 and 1.25 $\mu_B$/unit, respectively. As the tensile strain increases, the magnetic moments of MXenes are greatly enhanced and a transition from nonmagnetism to ferromagnetism is observed for those nonmagnetic MXenes at zero strains. The most distinct transition is found in Hf$_2$C, in which the magnetic moment is elevated to 1.5 $\mu_B$/unit at a strain of 15%. We further show that the magnetic properties of Hf$_2$C are attributed to the band shift mainly composed of Hf(5$d$) states. This strain-tunable magnetism can be utilized to design future spintronics based on MXenes

Gas adsorption on MoS2 monolayer from first-principles calculations

First-principles calculations within density functional theory (DFT) have been carried out to investigate the adsorption of various gas molecules including CO, CO2, NH3, NO and NO2 on MoS2 monolayer in order to fully exploit the gas sensing capabilities of MoS2. By including van der Waals (vdW) interactions between gas molecules and MoS2, we find that only NO and NO2 can bind strongly to MoS2 sheet with large adsorption energies, which is in line with experimental observations. The charge transfer and the variation of electronic structures are discussed in view of the density of states and molecular orbitals of the gas molecules. Our results thus provide a theoretical basis for the potential applications of MoS2 monolayer in gas sensing and give an explanation for recent experimental findings.Comment: 15 pages, 5 figure

Eight Years of Research Advances in Bourbon Virus, a Tick-borne Thogotovirus of the Orthomyxovirus Family

Bourbon virus (BRBV) was first isolated from a blood sample collected from a male patient living in Bourbon County, Kansas, during the spring of 2014. The patient later died because of complications associated with multiorgan failure. Several deaths due to BRBV infection have since been reported in the United States, and misdiagnosed cases are often undercounted. BRBV is a member of the genus Thogotovirus of the Orthomyxoviridae family, and is transmitted through the Lone Star tick, Amblyomma americanum , in North America. Currently, no specific antiviral agents or vaccines are available to treat or prevent BRBV infection. Several small-molecular compounds have been identified to effectively inhibit BRBV infection of in vitro cell cultures at the single- or sub-micromolar level. Favipiravir, an RNA-dependent RNA polymerase inhibitor, has been found to prevent death in type I interferon receptor knockout mice with BRBV infection

Stray flux-based rotation angle measurement for bearing fault diagnosis in variable-speed BLDC motors

Angle of rotation is a key parameter in motor fault diagnosis under varying speed conditions, and is usually measured by an optical encoder. However, the use of encoders is intrusive and in many scenarios its signal is difficult to access due to technical or commercial reasons. In this study, a novel rotation angle measurement method based on stray flux analysis is proposed and applied to bearing fault diagnosis of brushless direct-current (BLDC) motors. The measurement accuracy of the proposed method is comparable to that from an encoder. The developed method is flexible, noninvasive, and nondestructive. It is easy to implement and eliminates the need for long cables and access of the motor control system. The proposed method can be extended to the diagnosis of motor electrical and drive faults. If implemented with an Internet of Things (IoT) or a hand-held device, it can further improve the reliability of sensorless motor drive systems in industrial automation so as to meet Industry 4.0 requirements

Rapamycin Enhances Mitophagy and Attenuates Apoptosis After Spinal Ischemia-Reperfusion Injury

The spinal cord is extremely vulnerable to ischemia-reperfusion (I/R) injury, and the mitochondrion is the most crucial interventional target. Rapamycin can promote autophagy and exert neuroprotective effects in several diseases of the central nervous system. However, the impact of rapamycin via modulating mitophagy and apoptosis after spinal cord ischemia-reperfusion injury remains unclear. This study was undertaken to investigate the potential role of rapamycin in modulating mitophagy and mitochondria-dependent apoptosis using the spinal cord ischemia-reperfusion injury (SCIRI) mouse model. We found that rapamycin significantly (p < 0.05) enhanced mitophagy by increasing the translocation of p62 and Parkin to the damaged mitochondria in the mouse spinal cord injury model. At the same time, rapamycin significantly (p < 0.05) decreased mitochondrial apoptosis related protein (Apaf-1, Caspase-3, Caspase-9) expression by inhibiting Bax translocation to the mitochondria and the release of the cytochrome c from the mitochondria. After 24 h following SCIRI, rapamycin treatment reduced the TUNEL+ cells in the spinal cord ischemic tissue and improved the locomotor function in these mice. Our results therefore demonstrate that rapamycin can improve the locomotor function by promoting mitophagy and attenuating SCIRI -induced apoptosis, indicating its potential therapeutic application in a spinal cord injury

Prior knowledge auxiliary for few-shot pest detection in the wild

One of the main techniques in smart plant protection is pest detection using deep learning technology, which is convenient, cost-effective, and responsive. However, existing deep-learning-based methods can detect only over a dozen common types of bulk agricultural pests in structured environments. Also, such methods generally require large-scale well-labeled pest data sets for their base-class training and novel-class fine-tuning, and these significantly hinder the further promotion of deep convolutional neural network approaches in pest detection for economic crops, forestry, and emergent invasive pests. In this paper, a few-shot pest detection network is introduced to detect rarely collected pest species in natural scenarios. Firstly, a prior-knowledge auxiliary architecture for few-shot pest detection in the wild is presented. Secondly, a hierarchical few-shot pest detection data set has been built in the wild in China over the past few years. Thirdly, a pest ontology relation module is proposed to combine insect taxonomy and inter-image similarity information. Several experiments are presented according to a standard few-shot detection protocol, and the presented model achieves comparable performance to several representative few-shot detection algorithms in terms of both mean average precision (mAP) and mean average recall (mAR). The results show the promising effectiveness of the proposed few-shot detection architecture

Treatment of Surgical Brain Injury by Immune Tolerance Induced by Peripheral Intravenous Injection of Biotargeting Nanoparticles Loaded With Brain Antigens

Once excessive, neurological disorders associated with inflammatory conditions will inevitably cause secondary inflammatory damage to brain tissue. Immunosuppressive therapy can reduce the inflammatory state, but resulting infections can expose the patient to greater risk. Using specific immune tolerance organs or tissues from the body, brain antigen immune tolerance treatment can create a minimal immune response to the brain antigens that does not excessively affect the body's immunity. However, commonly used immune tolerance treatment approaches, such as those involving the nasal, gastrointestinal mucosa, thymus or liver portal vein injections, affect the clinical conversion of the therapy due to uncertain drug absorption, or inconvenient routes of administration. If hepatic portal intravenous injections of brain antigens could be replaced by normal peripheral venous infusion, the convenience of immune tolerance treatment could certainly be greatly increased. We attempted to encapsulate brain antigens with minimally immunogenic nanomaterials, to control the sizes of nanoparticles within the range of liver Kupffer cell phagocytosis and to coat the antigens with a coating material that had an affinity for liver cells. We injected these liver drug-loaded nanomaterials via peripheral intravenous injection. With the use of microparticles with liver characteristics, the brain antigens were transported into the liver out of the detection of immune armies in the blood. This approach has been demonstrated in rat models of surgical brain injury. It has been proven that the immune tolerance of brain antigens can be accomplished by peripheral intravenous infusion to achieve the effect of treating brain trauma after operations, which simplifies the clinical operation and could elicit substantial improvements in the future