Few-molecule reservoir computing experimentally demonstrated with surface enhanced Raman scattering and ion-gating stimulation

Reservoir computing (RC) is a promising solution for achieving low power consumption neuromorphic computing, although the large volume of the physical reservoirs reported to date has been a serious drawback in their practical application. Here, we report the development of a few-molecule RC that employs the molecular vibration dynamics in the para-mercaptobenzoic acid (pMBA) detected by surface enhanced Raman scattering (SERS) with tungsten oxide nanorod/silver nanoparticles (WOx@Ag-NPs). The Raman signals of the pMBA molecules, adsorbed at the SERS active site of WOx@Ag-NPs, were reversibly perturbated by the application of voltage-induced local pH changes in the vicinity of the molecules, and then used to perform RC of pattern recognition and prediction tasks. In spite of the small number of molecules employed, our system achieved good performance, including 95.1% to 97.7% accuracy in various nonlinear waveform transformations and 94.3% accuracy in solving a second-order nonlinear dynamic equation task. Our work provides a new concept of molecular computing with practical computation capabilities.Comment: 22 pages, 4 figure

A high-performance deep reservoir computing experimentally demonstrated with ion-gating reservoirs

While physical reservoir computing (PRC) is a promising way to achieve low power consumption neuromorphic computing, its computational performance is still insufficient at a practical level. One promising approach to improving PRC performance is deep reservoir computing (deep-RC), in which the component reservoirs are multi-layered. However, all of the deep-RC schemes reported so far have been effective only for simulation reservoirs and limited PRCs, and there have been no reports of nanodevice implementations. Here, as the first nanodevice implementation of Deep-RC, we report a demonstration of deep physical reservoir computing using an ion gating reservoir (IGR), which is a small and high-performance physical reservoir. While previously reported Deep-RC scheme did not improve the performance of IGR, our Deep-IGR achieved a normalized mean squared error of 0.0092 on a second-order nonlinear autoregressive moving average task, with is the best performance of any physical reservoir so far reported. More importantly, the device outperformed full simulation reservoir computing. The dramatic performance improvement of the IGR with our deep-RC architecture paves the way for high-performance, large-scale, physical neural network devices.Comment: 21 pages, 6 figure

Fabrication of magnetic tunnel junctions with a metastable bcc Co3Mn disordered alloy as a bottom electrode

We fabricated MgO barrier magnetic tunnel junctions (MTJs) with a Co3Mn alloy bottom and FeCoB top electrodes. The (001)-oriented epitaxial films of the metastable bcc Co3Mn disordered alloys obtained showed saturation magnetization of approximately 1640 emu/cm3. The transmission electron microscopy showed that the MgO barrier was epitaxially grown on the Co3Mn electrode. Tunnel magnetoresistance of approximately 150% was observed at room temperature after the annealing of MTJs at 350◦C, indicating that bcc Co3Mn alloys have relatively high spin polarization

Magnetic tunnel junctions with a B2-ordered CoFeCrAl equiatomic Heusler alloy

The equiatomic quaternary Heusler alloy CoFeCrAl is a candidate material for spin-gapless semiconductors (SGSs). However, to date, there have been no experimental attempts at fabricating a junction device. This paper reports a fully epitaxial (001)-oriented MgO barrier magnetic tunnel junction (MTJ) with CoFeCrAl electrodes grown on a Cr buffer. X-ray and electron diffraction measurements show that the (001) CoFeCrAl electrode films with atomically flat surfaces have a B2-ordered phase. The saturation magnetization is 380 emu/cm3, almost the same as the value given by the Slater–Pauling–like rule, and the maximum tunnel magnetoresistance ratios at 300 K and 10 K are 87% and 165%, respectively. Cross-sectional electron diffraction analysis shows that the MTJs have MgO interfaces with fewer dislocations. The temperature- and bias-voltage dependence of the transport measurements indicates magnon-induced inelastic electron tunneling overlapping with the coherent electron tunneling. X-ray magnetic circular dichroism (XMCD) measurements show a ferromagnetic arrangement of the Co and Fe magnetic moments of B2-ordered CoFeCrAl, in contrast to the ferrimagnetic arrangement predicted for the Y -ordered state possessing SGS characteristics. Ab-initio calculations taking account of the Cr-Fe swap disorder qualitatively explain the XMCD results. Finally, the effect of the Cr-Fe swap disorder on the ability for electronic states to allow coherent electron tunneling is discussed

Implantation of Liquid Nitrogen Frozen Tumor Tissue after Posterior Decompression and Stabilization for Metastatic Spinal Tumors

Study DesignA retrospective study.PurposeTo evaluate the immunity-enhancing effect of implantation of a liquid nitrogen-treated tumor.Overview of LiteratureWe have developed a new technique of implanting a tumor frozen in liquid nitrogen after posterior decompression and stabilization, with the aim of enhancing antitumor immunity in order to prolong the survival period of the patient. In the current study, the immunity-enhancing effect of this new technique has been evaluated.MethodsThe subjects were 19 patients in whom we had earlier performed decompression and stabilization between April 2011 and September 2013. The 19 subjects were divided into two groups, namely a frozen autologous tumor tissue implantation group (n=15; "implantation group"), which consisted of patients, who underwent implantation with autologous tumor tissue frozen in liquid nitrogen, and a control group (n=4), which consisted of patients, who did not undergo autologous cancer transplantation. To evaluate the immunity-enhancing effect of the protocol, plasma cytokines (interferon [IFN]-γ and interleukin [IL]-12) were analyzed before surgery and a month after surgery.ResultsThe mean rate of increase in IFN-γ was significantly higher in the implantation group (p=0.03). Regarding IL-12, no significant difference was observed between the groups, although the implantation group exhibited increased levels of IL-12 (p=0.22).ConclusionsDecompression and stabilization combined with autologous frozen tumor cell implantation can enhance cancer immunity in metastatic spinal tumor patients. It is hypothesized that this procedure might prevent local recurrence and prolong survival period

Surgical site infection after total en bloc spondylectomy: Risk factors and the preventive new technology

Background context Surgical site infection (SSI) associated with instruments remains a serious and common complication in patients who undergo total en bloc spondylectomy (TES). It is very important that the risk factors for SSI are known to prevent it.Purpose The purpose of the study was to identify independent risk factors for SSI after TES and evaluate the positive effect of iodine-supported spinal instruments in the prevention of SSI after TES.Study design This is a retrospective clinical study.Patient sample One hundred twenty-five patients who underwent TES for vertebral tumor were evaluated.Outcome measures Incidence rate of SSI, risk factors for SSI after TES, and safety of iodine-supported spinal instruments were the outcome measures.Methods Risk factors for SSI were analyzed using logistic regression. In recent 69 patients with iodine-supported spinal instruments, the thyroid hormone levels in the blood were examined to confirm if iodine from the implant influenced thyroid function. Postoperative radiological evaluations were performed regularly.Results The rate of SSI was 6.4% (8/125 patients). By multivariate logistic regression, combined anterior and posterior approach and nonuse of iodine-supported spinal instruments were associated with an increased risk of SSI. The rate of SSI without iodine-supported spinal instruments was 12.5%, whereas the rate with iodine-supported spinal instruments was 1.4%. This difference was statistically significant. There were no detected abnormalities of thyroid gland function with the use of iodine-supported instruments. Among the 69 patients with iodine-supported spinal instruments, 2 patients required additional surgery because of instrument failure. However, there were no obvious involvements with the use of iodine-supported spinal instruments.Conclusions This study identified combined anterior and posterior approach and nonuse of iodine-supported spinal instruments to be independent risk factors for SSI after TES. Iodine-supported spinal instrument was extremely effective for prevention of SSI in patients with compromised status, and it had no detection of cytotoxic or adverse effects on the patients

MicroRNA-338-3p and microRNA-451 contribute to the formation of basolateral polarity in epithelial cells

MicroRNAs are small noncoding RNA species, some of which are playing important roles in cell differentiation. However, the level of participations of microRNAs in epithelial cell differentiation is largely unknown. Here, utilizing an epithelial differentiation model with T84 cells, we demonstrate that miR-338-3p and miR-451 contribute to the formation of epithelial basolateral polarity by facilitating translocalization of β1 integrin to the basolateral membrane. Among 250 microRNAs screened in this study, the expression levels of four microRNAs (miR-33a, 210, 338-3p and 451) were significantly elevated in the differentiated stage of T84 cells, when epithelial cell polarity was established. To investigate the involvement of these microRNAs in terms of epithelial cell polarity, we executed loss-of- and gain-of-function analyses of these microRNAs. The blockade of endogenous miR-338-3p or miR-451 via each microRNA-specific antisense oligonucleotides inhibited the translocalization of β1 integrin to the basolateral membrane, whereas inhibition of miR-210 or miR-33a had no effect on it. On the other hand, simultaneous transfection of synthetic miR-338-3p and miR-451 accelerated the translocalization of β1 integrin to the basolateral membrane, although the introduction of individual synthetic microRNAs exhibited no effect. Therefore, we concluded that both miR-338-3p and miR-451 are necessary for the development of epithelial cell polarity

Extreme deformability of insect cell membranes is governed by phospholipid scrambling

昆虫の細胞は柔らかい！ --細胞膜を柔らかくするタンパク質を発見--. 京都大学プレスリリース. 2021-06-09.Organization of dynamic cellular structure is crucial for a variety of cellular functions. In this study, we report that Drosophila and Aedes have highly elastic cell membranes with extremely low membrane tension and high resistance to mechanical stress. In contrast to other eukaryotic cells, phospholipids are symmetrically distributed between the bilayer leaflets of the insect plasma membrane, where phospholipid scramblase (XKR) that disrupts the lipid asymmetry is constitutively active. We also demonstrate that XKR-facilitated phospholipid scrambling promotes the deformability of cell membranes by regulating both actin cortex dynamics and mechanical properties of the phospholipid bilayer. Moreover, XKR-mediated construction of elastic cell membranes is essential for hemocyte circulation in the Drosophila cardiovascular system. Deformation of mammalian cells is also enhanced by the expression of Aedes XKR, and thus phospholipid scrambling may contribute to formation of highly deformable cell membranes in a variety of living eukaryotic cells

隠れマルコフモデルを用いたマウス状態の自動判定と2値マルコフモデルによるコンソミックマウス系統の特徴付け

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