RELATIONSHIP BETWEEN PERIODONTAL DISEASE AND ABO BLOOD GROUP PHENOTYPES-A CROSS SECTIONAL RETROSPECTIVE STUDY

Objective: Numerous epidemiological studies have been carried out to assess the association of ABO blood typing and systemic diseases. However, the research is still at the infancy stage with regards to the dental field. Periodontitis, being one of the most prevalent diseases in the oral cavity can be supposed to be influenced by the blood grouping pattern among patients. The present cross-sectional study was carried out to asses the relationship between periodontal disease status and the ABO blood group.Methods: In a retrospective study of 2014, patients who reported to Saveetha Dental College and Hospital and diagnosed with chronic periodontitis, both localized and generalized forms were included. Demographic data, diagnostic and the ABO blood grouping information were procured from the case records of 410 subjects and then analysed.Results: Among the 410 individuals, 245 were diagnosed with localized chronic periodontitis whereas 165 subjects had suffered from generalized chronic periodontitis. A high fraction of the localized periodontitis population (20.97%) was of the blood group ‘B.' Similarly(12.92%) of the generalized periodontitis cases belonged to either ‘B' or ‘O' blood groups. The least affected blood group was ‘AB.'Conclusion: This cross-sectional study shows a definite relation between blood typing and periodontal disease. Further studies are required in order to validate the usage of blood groups as risk predictors for periodontitis.Â

Anisotropic magnetoresistance in an antiferromagnetic semiconductor

arXiv:1303.4704v1.-- et al.Recent studies in devices comprising metal antiferromagnets have demonstrated the feasibility of a novel spintronic concept in which spin-dependent phenomena are governed by an antiferromagnet instead of a ferromagnet. Here we report experimental observation of the anisotropic magnetoresistance in an antiferromagnetic semiconductor Sr2IrO4. Based on ab initio calculations, we associate the origin of the phenomenon with large anisotropies in the relativistic electronic structure. The antiferromagnet film is exchange coupled to a ferromagnet, which allows us to reorient the antiferromagnet spin-axis in applied magnetic fields via the exchange spring effect. We demonstrate that the semiconducting nature of our AFM electrode allows us to perform anisotropic magnetoresistance measurements in the currentperpendicular- to-plane geometry without introducing a tunnel barrier into the stack. Temperature- dependent measurements of the resistance and anisotropic magnetoresistance highlight the large, entangled tunabilities of the ordinary charge and spin-dependent transport in a spintronic device utilizing the antiferromagnet semiconductor.We acknowledge the support from the NSF (Nanosystems Engineering Research Center for Translational Applications of Nanoscale Multiferroic Systems, Cooperative Agreement Award EEC-1160504). We acknowledge partial support from the US Department of Energy (J.H.C., S.S. and R.R.) as well as the SRC-FAME programme through UCLA (C.R.-S.). T.J. acknowledges support from the EU European Research Council (ERC) advanced grant no. 268066, from the Ministry of Education of the Czech Republic grant no. LM2011026, from the Grant Agency of the Czech Republic grant no. 14-37427G and from the Academy of Sciences of the Czech Republic Praemium Academiae. X.M. acknowledges the Grant Agency of the Czech Republic No. P204/11/P339. A.B.S.Peer Reviewe

Experimental Evidence of Ferroelectric Negative Capacitance in Nanoscale Heterostructures

We report a proof-of-concept demonstration of negative capacitance effect in a nanoscale ferroelectric-dielectric heterostructure. In a bilayer of ferroelectric, Pb(Zr0.2Ti0.8)O3 and dielectric, SrTiO3, the composite capacitance was observed to be larger than the constituent SrTiO3 capacitance, indicating an effective negative capacitance of the constituent Pb(Zr0.2Ti0.8)O3 layer. Temperature is shown to be an effective tuning parameter for the ferroelectric negative capacitance and the degree of capacitance enhancement in the heterostructure. Landau's mean field theory based calculations show qualitative agreement with observed effects. This work underpins the possibility that by replacing gate oxides by ferroelectrics in MOSFETs, the sub threshold slope can be lowered below the classical limit (60 mV/decade)

Electrical control of magnetism by electric field and current-induced torques

While early magnetic memory designs relied on magnetization switching by locally generated magnetic fields, key insights in condensed matter physics later suggested the possibility to do it electrically. In the 1990s, Slonczewzki and Berger formulated the concept of current-induced spin torques in magnetic multilayers through which a spin-polarized current may switch the magnetization of a ferromagnet. This discovery drove the development of spin-transfer-torque magnetic random-access memories (STT-MRAMs). More recent research unveiled spin-orbit-torques (SOTs) and will lead to a new generation of devices including SOT-MRAMs. Parallel to these advances, multiferroics and their magnetoelectric coupling experienced a renaissance, leading to novel device concepts for information and communication technology such as the MESO transistor. The story of the electrical control of magnetization is that of a dance between fundamental research (in spintronics, condensed matter physics, and materials science) and technology (MRAMs, MESO, microwave emitters, spin-diodes, skyrmion-based devices, components for neuromorphics, etc). This pas de deux led to major breakthroughs over the last decades (pure spin currents, magnetic skyrmions, spin-charge interconversion, etc). As a result, this field has propelled MRAMs into consumer electronics products but also fueled discoveries in adjacent research areas such as ferroelectrics or magnonics. Here, we cover recent advances in the control of magnetism by electric fields and by current-induced torques. We first review fundamental concepts in these two directions, then discuss their combination, and finally present various families of devices harnessing the electrical control of magnetic properties for various application fields. We conclude by giving perspectives in terms of both emerging fundamental physics concepts and new directions in materials science.Comment: Final version accepted for publication in Reviews of Modern Physic

James F. Scott (1942-2020)

Obituari de James F. Soct

Training the polarization in integrated La0.15Bi0.85FeO3-based devices

The functionalities of BiFeO3-based magnetoelectric multiferroic heterostructures rely on the controlled manipulation of their ferroelectric domains and of the corresponding net in-plane polarization, as this aspect guides the voltage-controlled magnetic switching. Chemical substitution has emerged as a key to push the energy dissipation of the BiFeO3 into the attojoule range but appears to result in a disordered domain configuration. Using non-invasive optical second-harmonic generation on heavily La-substituted BiFeO3 films, it is shown that a weak net in-plane polarization remains imprinted in the pristine films despite the apparent domain disorder. It is found that this ingrained net in-plane polarization can be trained with out-of-plane electric fields compatible with applications. Operando studies on capacitor heterostructures treated in this way show the full restoration of the domain configuration of pristine BiFeO3 along with a giant net in-plane polarization enhancement. Thus, the experiments reveal a surprising robustness of the net in-plane polarization of BiFeO3 against chemical modification, an important criterion in ongoing attempts to integrate magnetoelectric materials into energy-efficient device