Growth of Adsorbed Additive Layer for Further Friction Reduction

Special Issue:6th European Conference on Tribology (ECOTRIB 2017)Boundary lubrication is one of the most interesting topics in the field of tribology, and a lot of studies have been conducted from the past for understanding the behaviour of boundary lubrication films. General boundary lubrication films are formed by the adsorption of additives mixed into lubricant, and then the tribological performances are drastically improved in many cases. However, there is still room for discussion on the “actual” behaviour of adsorbed additive layer in the tribological condition, that is, under high pressure and/or with external forces. This paper showed the “growing” behaviour of an adsorbed additive layer onto metal surface due to high pressure by means of neutron reflectometry in conjunction with the result obtained through cross‐sectional imaging by frequency‐modulation atomic force microscopy. In addition, the nanotribological study using atomic force microscopy with a colloidal probe showed that the coefficient of friction in the pre‐scratched area was lower than that in the non‐scratched area and that the reduction ratio for lubricant with additive was higher than that for lubricant without additive. This result indicates that growth of the adsorbed additive layer contributed more greatly to a reduction in the coefficient of friction

Development of Attitude Sensor using Deep Learning

A new method for attitude determination utilizing color earth images taken with COTS visible light camera is presented. The traditional earth camera has been used for coarse attitude determination by detecting the edge of the earth, and therefore it can only provide coarse and 2-axis information. In contrast, our method recognizes the ground pattern with an accuracy of sub-degrees and can provide 3-axis attitude information by comparing the detected ground pattern and the global map. Moreover, this method has advantages in the size, mass and cost of the detector system which consists of a cheap optical color camera and a single board computer. To demonstrate the method in space, we have developed a sensor system named “Deep Learning Attitude Sensor (DLAS)”. DLAS uses COTS camera modules and single board computers to reduce the cost. The obtained images are promptly analyzed with a newly developed real-time image recognition algorithms

Variable Shape Attitude Control Demonstration with Microsat Hibari

This paper presents the ongoing feasibility study and bus system for microsatellite “Hibari”. The main technical missions for Hibari is called “Variable Shape Attitude Control (VSAC)”. This VSAC is based on an idea to utilize a reaction torque when a part of the satellite structure, for example, solar array paddles is appropriately rotated by actuators. The previous research concluded that VSAC successfully achieved the rapid maneuvering while maintain the high attitude stability against disturbances [1], and thus, it can be applied to a variety of advanced attitude control missions. Hibari project also aims at its application to astronomical mission requiring high pointing stability and agile maneuvering. This paper is mainly comprised of 3 parts: detail mission statement, ongoing feasibility studies and bus system configuration. First, we mention the mission requirement and detail mission sequence for both technical and science missions. Second, we show the ongoing feasibility studies to confirm that all mission requirement is satisfied by VSAC. Third, this paper describes each subsystem configuration to meet the system requirement stated in the mission’s section. And then, we wrap up in the conclusion section and stated the future study for advanced VSAC use in the end

Analysis of prostate intensity- and volumetric-modulated arc radiation therapy planning quality with PlanIQTM

Purpose: The purpose of this study was to assess the quality of treatment planning using the PlanIQTM software and to investigate whether it is possible to improve the quality of treatment planning using the “Feasibility dose-volume histogram (DVH)TM” implemented in the PlanIQTM software. Methods: Using the PlanIQTM software, we retrospectively analyzed the learning curve regarding the quality of the treatment plans for 148 patients of prostate intensity-modulated radiation therapy and volumetric-modulated radiation therapy performed at our institution over the past eight years. We also sought to examine the possibility of improving treatment planning quality by re-planning in 47 patients where the quality of the target dose and the dose limits for organs at risk (OARs) were inadequate. The re-planning treatment plans referred to the Feasibility DVHTM implemented in the PlanIQTM software and modified the treatment planning system based on the target dose and OAR constraints. Results: Analysis of the learning curve of the treatment plans quality using PlanIQTM software retrospectively showed a trend of improvement in the treatment plan quality from year to year. The improvement in the treatment plans quality was more influenced by dose reduction in the OARs than by target coverage. In all cases where re-planning was performed, the improvement in the treatment plan's quality resulted in a better treatment plan than the one adopted for delivery to patients in the clinical plan. Conclusions: The PlanIQTM provided insights into the quality of the treatment plans at our institution and identified problems and areas for improvement in the treatment plans, allowing for the development of appropriate treatment plans for specific patients

Minimal upstream open reading frame of Per2 mediates phase fitness of the circadian clock to day/night physiological body temperature rhythm

全身の体内リズムを調和させるRNA配列の発見 --体温の日内変化に合わせてしなやかに調和させる--. 京都大学プレスリリース. 2023-03-07.Body temperature in homeothermic animals does not remain constant but displays a regular circadian fluctuation within a physiological range (e.g., 35°C–38.5°C in mice), constituting a fundamental systemic signal to harmonize circadian clock-regulated physiology. Here, we find the minimal upstream open reading frame (uORF) encoded by the 5′ UTR of the mammalian core clock gene Per2 and reveal its role as a regulatory module for temperature-dependent circadian clock entrainment. A temperature shift within the physiological range does not affect transcription but instead increases translation of Per2 through its minimal uORF. Genetic ablation of the Per2 minimal uORF and inhibition of phosphoinositide-3-kinase, lying upstream of temperature-dependent Per2 protein synthesis, perturb the entrainment of cells to simulated body temperature cycles. At the organismal level, Per2 minimal uORF mutant skin shows delayed wound healing, indicating that uORF-mediated Per2 modulation is crucial for optimal tissue homeostasis. Combined with transcriptional regulation, Per2 minimal uORF-mediated translation may enhance the fitness of circadian physiology

Potential therapeutic applications of targeting signal-transducing adaptor protein-2 in autoimmune diseases

Adaptor proteins are involved in various immune responses via the modulation of many signaling pathways. Signal-transducing adaptor protein-2 (STAP-2) is an adaptor protein that contains typical domains such as the pleckstrin homology (PH) domain, Src homology domain, and a proline-rich region from the N-terminal region. In T cells, STAP-2 positively regulates T cell receptor (TCR)-mediated signaling by associating with CD3ζ immunoreceptor tyrosine-based activation motifs (ITAMs) and lymphocyte-specific protein tyrosine kinase (LCK). Therefore, a peptide that inhibits the interaction between STAP-2 and CD3ζ ITAMs is likely to suppress TCR-mediated T cell activation, as well as T cell-mediated diseases. As expected, the peptide successfully inhibited the STAP-2/CD3ζ ITAM interaction and suppressed TCR-mediated signaling, cell proliferation, and interleukin (IL)-2 production in human/murine T cells. Furthermore, this inhibitor suppressed the pathogenesis of experimental autoimmune encephalomyelitis (EAE), which is widely recognized as a mouse model of multiple sclerosis, via the downregulation of T cell activation and infiltration of T helper (Th) 1/Th17 cells. These results suggest a new strategy for the treatment of multiple sclerosis and other immune diseases

Development and Initial On-orbit Performance of Multi-Functional Attitude Sensor using Image Recognition

This paper describes a multi-functional attitude sensor mounted on the “Innovative Satellite 1st” led by Japan Aerospace Exploration Agency which was launched in January 2019. In order to achieve the high accuracy determination in low cost, we developed a novel attitude sensor utilizing real-time image recognition technology, named “Deep Learning Attitude Sensor (DLAS)”. DLAS has two type of attitude sensors: Star Tracker(STT) and Earth Camera (ECAM). For the low-cost development, we adopted commercial off-the-shelf cameras. DLAS uses real-time image recognition technology and a new attitude determination algorithm. In this paper, we present the missions, methods and system configuration of DLAS and initial results of on-orbit experiment that was conducted after the middle of February 2019, and it is confirmed that attitude determinations using ECAM and STT are performed correctly

Signal-transducing adaptor protein-2 modulates T-cell functions

Immune responses are orchestrated by controlling the initiation, magnitude, and duration of various signaling pathways. Adaptor proteins act as positive or negative regulators by targeting critical molecules of signaling cascades. Signal-transducing adaptor protein-2 (STAP-2) contains typical features of adaptor proteins, like a pleckstrin homology (PH) domain in the N-terminal region and a Src homology 2 (SH2) domain in the central region. STAP-2 binds to a variety of signaling or transcriptional molecules to control multiple steps of inflammatory/immune responses. STAP-2 enhances T-cell receptor (TCR)-mediated signaling via the association with TCR-proximal CD3ζ immunoreceptor tyrosine-based activation motifs (ITAMs) and lymphocyte-specific protein tyrosine kinase (Lck). STAP-2 decreases adherence of T-cells to fibronectin (FN) through an association with focal adhesion kinase (Fak) and Casitas B-lineage Lymphoma (c-Cbl), and increases chemotaxis of T-cells toward stromal cell-derived factor-1α (SDF-1α) through interactions with Vav1 and Ras-related C3 botulinum toxin substrate 1 (Rac1). STAP-2 positively regulates activation-induced cell deathrough the association with Fas and caspase-8. This review describes the current knowledge of the roles of STAP-2 in T-cell-dependent immune responses and the possible clinical utility of STAP-2-targeting therapies