Engineering magnetic nanostructures with inverse hysteresis loops

Top-down lithography techniques allow the fabrication of nanostructured elements with novel spin configurations, which provide a new route to engineer and manipulate the magnetic response of sensors and electronic devices and understand the role of fundamental interactions in materials science. In this study, shallow nanostructure-patterned thin films were designed to present inverse magnetization curves, i.e., an anomalous magnetic mechanism characterized by a negative coercivity and negative remanence. This procedure involved a method for manipulating the spin configuration that yielded a negative coercivity after the patterning of a single material layer. Patterned NiFe thin films with trench depths between 15%-25% of the total film thickness exhibited inverse hysteresis loops for a wide angular range of the applied field and the trench axis. A model based on two exchange-coupled subsystems accounts for the experimental results and thus predicts the conditions for the appearance of this magnetic behavior. The findings of the study not only advance our understanding of patterning effects and confined magnetic systems but also enable the local design and control of the magnetic response of thin materials with potential use in sensor engineering.

A GmNINa-miR172c-NNC1 Regulatory Network Coordinates the Nodulation and Autoregulation of Nodulation Pathways in Soybean

Symbiotic root nodules are root lateral organs of plants in which nitrogen-fixing bacteria(rhizobia)convert atmospheric nitrogen to ammonia.The formation and number of nodules in legumes are precisely controlled by a rhizobia-induced signal cascade and host-controlled autoregulation of nodulation(AON).However,how these pathways are integrated and their underlying mechanisms are unclear.Here,we report that microRNA172c(miR172c)activates soybean(Glycine max)R hizobia-induced CLE1(GmRICI)and GmRIC2 by removing the transcriptional repression of these genes by Nodule Number Control 1(NNC1),leading to the activation of the AON pathway.NNC1 interacts with GmNINa,the soybean ortholog of Lotus NODULE INCEPTION(NIN),and hampers its transcriptional activation o i G m RICI and GmRIC2.Importantly,GmNINa acts as a transcriptional activator of miR172c.Intriguingly,NNC1 can transcriptionally repress miR172c expression,adding a negative feedback loop into the NNC1 regulatory network.Moreover,GmNINa interacts with NNC1 and can relieve the NNC1-mediated repression of miR172c transcription.Thus,the GmNINa-miR172c-NNC1 network is a master switch that coordinately regulates and optimizes NF and AON signaling,supporting the balance between nodulation and AON in soybean.

Rapamycin in fibrotic diseases： beneficial or detrimental agent？

apamvcin was first isolated from a strain of Sreptomyces hygroscopicus in the early 1970s froma soil sample taken on Easter Island. Because the antiproliferative effects of rapamycin on yeast cell, as well as B and T lymphocytes, it was first identified as an antimicrobial agent with potent immunosuppressive activity and has been used in antirejection therapy.

Coordinated Control of DFIG Converters to Comply with Reactive Current Requirements in Emerging Grid Codes

The doubly-fed induction generator(DFIG)is considered to provide a low-reactance path in the negative-sequence system and naturally comply with requirements on the negative-sequence reactive current in emerging grid codes.This paper shows otherwise and how the control strategy of converters plays a key role in the formation of the active and reactive current components.After investigating the existing control strategies from the perspective of grid code compliance and showing how they fail in addressing emerging requirements on the negative-sequence reactive current,we propose a new coordinated control strategy that complies with reactive current requirements in grid codes in the positive-and negative-sequence systems.The proposed method fully takes advantage of the current and voltage capacities of both the rotor-side converter(RSC)and grid-side converter(GSC),which enables the grid code compliance of the DFIG under unbalanced three-phase voltages due to asymmetrical faults.The mathematical investigations and proposed strategy are validated with detailed simulation models using the Electric Power Research Institute(EPRI)benchmark system.The derived mathematical expressions provide analytical clarifications on the response of the DFIG in the negative-sequence system from the grid perspective.

A 2.5-V 56-mW baseband chain in a multistandard TV tuner for mobile and multimedia applications

This paper presents post-layout simulated results of an analog baseband chain for mobile and multimedia applications in a 0.13-μm SiGe BiCMOS process.A programmable 7th-order Chebyshev low pass filter with a calibration circuit is used in the analog baseband chain,and the programmable bandwidth is 1.8/2.5/3/3.5/4 MHz with an attenuation of 26/62 dB at offsets of 1.25/4 MHz.The baseband programmable gain amplifier can achieve a linear 40-dB gain range with 0.5-dB steps.Design trade-offs are carefully considered in designing the baseband circuit,and an automatic calibration circuit is used to achieve the bandwidth accuracy of 2%.A DC offset cancellation loop is also introduced to remove the offset from the layout and self-mixing,and the remaining offset voltage is only 1.87 mV.Implemented in a 0.13-μm SiGe technology with a 0.6-mm2 die size,this baseband achieves IIP3 of 23.16 dBm and dissipates 22.4 mA under a 2.5-V supply.