171 research outputs found

    Microwave band on-chip coil technique for single electron spin resonance in a quantum dot

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    Microwave band on-chip microcoils are developed for the application to single electron spin resonance measurement with a single quantum dot. Basic properties such as characteristic impedance and electromagnetic field distribution are examined for various coil designs by means of experiment and simulation. The combined setup operates relevantly in the experiment at dilution temperature. The frequency responses of the return loss and Coulomb blockade current are examined. Capacitive coupling between a coil and a quantum dot causes photon assisted tunneling, whose signal can greatly overlap the electron spin resonance signal. To suppress the photon assisted tunneling effect, a technique for compensating for the microwave electric field is developed. Good performance of this technique is confirmed from measurement of Coulomb blockade oscillations.Comment: 7 pages, 8 figures, Accepted for publication in Rev. Sci. Instrum. The bibliography file is update

    The Autonomous System Architecture of the Small SAR Satellite Operation System and On-Orbit Autonomous Operation Experiences

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    We are developing a small SAR (Synthetic Aperture Radar) satellite for our commercial solution business. Our goal is to deploy at least 30 small SAR satellites in orbit and enable frequent and persistent observations until the Mid 2020s. We launched the satellite on 15th December 2020 by Rocket Lab\u27s Electron. We waited for a month until we took the first image to confirm the complete evacuation of the residual air and contaminations to prevent any hazardous electrical discharge. We took the first image on 8th February. The satellite is now operating in a fine state and acquiring images requested by the customers. We will make six satellite constellation until 2023. We also describe our system architecture including our solution business and the satellite development. Our business development team and the satellite development team are communicating with each other for adequate system architecture and agile satellite development. Our business development team acquires many novel needs from our customers. One of our goals is an agile reflection of the user\u27s needs for the satellite development. We are now establishing a process and an organization to extract those business needs, analyze them and identify the key requirements for the satellite performances and functions. We believe that one important challenge is to achieve application layer integration from a customer business system to a satellite on-board software through solution platform, data platform, satellite control ground system, and the satellite itself. We try to harmonize the software and information processes of the application layer, although the platform where the application is located, the organization where staffs belong, and their culture are different. We wish our activities contribute to our small satellite community or ecosystem and a system architecture including component suppliers, communication service providers, and data processing service providers

    Association of the malate dehydrogenase‑citrate synthase metabolon is modulated by intermediates of the Krebs tricarboxylic acid cycle

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    Mitochondrial malate dehydrogenase (MDH)-citrate synthase (CS) multi-enzyme complex is a part of the Krebs tricarboxylic acid (TCA) cycle ‘metabolon’ which is enzyme machinery catalyzing sequential reactions without diffusion of reaction intermediates into a bulk matrix. This complex is assumed to be a dynamic structure involved in the regulation of the cycle by enhancing metabolic flux. Microscale Thermophoresis analysis of the porcine heart MDH-CS complex revealed that substrates of the MDH and CS reactions, NAD+ and acetyl-CoA, enhance complex association while products of the reactions, NADH and citrate, weaken the affinity of the complex. Oxaloacetate enhanced the interaction only when it was present together with acetyl-CoA. Structural modeling using published CS structures suggested that the binding of these substrates can stabilize the closed format of CS which favors the MDH-CS association. Two other TCA cycle intermediates, ATP, and low pH also enhanced the association of the complex. These results suggest that dynamic formation of the MDH-CS multienzyme complex is modulated by metabolic factors responding to respiratory metabolism, and it may function in the feedback regulation of the cycle and adjacent metabolic pathways

    On-Orbit Demonstrations of Robust Autonomous Operations on Cubesat

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    As we accumulate experiences of satellite developments, we clearly recognize the importance of successful operations and difficulty to achieve them. There are many anomalous events in orbit especially for small satellites. It is costly or impossible to consider all anomalies in advance. The autonomous operation functions, we have developed, can operate the satellite without operators and achieve operation intents. The functions have the satellite behavior (state) models and the given operation intents. They generate the on-board operation procedures from the behavior models and execute them. Even if the status may not transit as expected due to anomalies, they can re-recognize the new status, generate the operation procedures again, and achieve the operation intents robustly. We have demonstrated the autonomous operation functions on a 3U CubeSat called TRICOM-1R that was launched by the newly developed and dedicated small satellite launcher SS-520 on 3rd Feb. 2018. The autonomous functions worked correctly and tried turning on the cameras without any predetermined operation procedures during the very first cycle of the orbit. The demonstration of them has successfully completed. We have several CubeSats and small satellites now in development and we will implement the upgraded version of the autonomous functions on them

    The Development Status of the First Demonstration Satellite of Our Commercial Small Synthetic Aperture Radar Satellite Constellation

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    Expectations for SAR (Synthetic Aperture Radar) satellites that can observe a target area through clouds and during nighttime are emerging, especially in Asia where high cloud cover rate prevent from the satellite monitoring with optical sensors. We are now developing a small SAR satellite based on technologies of ImPACT (Impulsing PAradigm Change through disruptive Technologies) program. This program aims to develop a responsive earth observation system with the small SAR satellite, originally target for disaster monitoring. We will build a constellation of the small SAR satellites to realize short term revisits, shorter than one day to take advantage of SAR sensor that can acquire data regardless of weather and time in a day. We expect the constellation expands needs of the SAR data to business and private decision making, and develop a market for commercial use. We have almost completed the development of mission FM components of the first demo satellite. The bus system is under EM testing and FM procurements. We will launch the first demo satellite in Q1 of 2020. We are already preparing to build the second satellite and will make six satellite constellation until 2021. Our final goal is to build a constellation of 25 satellites

    NTRC Plays a Crucial Role in Starch Metabolism, Redox Balance, and Tomato Fruit Growth

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    NADPH-thioredoxin reductase C (NTRC) forms a separate thiol-reduction cascade in plastids, combining both NADPHthioredoxin reductase and thioredoxin activities on a single polypeptide. While NTRC is an important regulator of photosynthetic processes in leaves, its function in heterotrophic tissues remains unclear. Here, we focus on the role of NTRC in developing tomato (Solanum lycopersicum) fruits representing heterotrophic storage organs important for agriculture and human diet. We used a fruit-specific promoter to decrease NTRC expression by RNA interference in developing tomato fruits by 60% to 80% compared to the wild type. This led to a decrease in fruit growth, resulting in smaller and lighter fully ripe fruits containing less dry matter and more water. In immature fruits, NTRC downregulation decreased transient starch accumulation, which led to a subsequent decrease in soluble sugars in ripe fruits. The inhibition of starch synthesis was associated with a decrease in the redox-activation state of ADP-Glc pyrophosphorylase and soluble starch synthase, which catalyze the first committed and final polymerizing steps, respectively, of starch biosynthesis. This was accompanied by a decrease in the level of ADP-Glc. NTRC downregulation also led to a strong increase in the reductive states of NAD(H) and NADP(H) redox systems. Metabolite profiling of NTRC-RNA interference lines revealed increased organic and amino acid levels, but reduced sugar levels, implying that NTRC regulates the osmotic balance of developing fruits. These results indicate that NTRC acts as a central hub in regulating carbon metabolism and redox balance in heterotrophic tomato fruits, affecting fruit development as well as final fruit size and qualit

    Sprouting alters metabolite and peptide contents in the gastrointestinal digest of soybean and enhances in-vitro anti-inflammatory activity

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    Sprouting of soybeans can enhance the release of health-beneficial bioactive compounds, especially peptides, and metabolites, while gastrointestinal (GI) digestion alters their biotransformation and bioaccessibility. The present study aimed to evaluate the effect of soybean sprouting and GI digestion in modulating its anti-inflammatory activity. Soybeans were soaked in water overnight (Day 0) and sprouted for two and four days, subjected to simulated GI digestion, and human intestinal epithelial cells (Caco-2) were pretreated (2 h) with soybean sprout digest (SSD: 1000 μg/mL) before inflammation induction with IL-1β. Pre-treatment with Day 4 SSD specifically reduced the secretion of cytokine IL-8 by 19.5%. Sprouting for four days and GI digestion significantly increased the abundance of metabolites, including valine, isoleucine, citrulline, and trigonelline. Furthermore, the abundance of peptides with polar-hydrophilic and charged amino acids was explicitly accumulated in the Day 4 SSD up to 6-fold. These metabolites and peptides are potentially responsible for the observed anti-inflammatory effects

    Antisense Suppression of the Small Chloroplast Protein CP12 in Tobacco Alters Carbon Partitioning and Severely Restricts Growth

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    Abstract The thioredoxin-regulated chloroplast protein CP12 forms a multienzyme complex with the Calvin-Benson cycle enzymes phosphoribulokinase (PRK) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH). PRK and GAPDH are inactivated when present in this complex, a process shown in vitro to be dependent upon oxidized CP12. The importance of CP12 in vivo in higher plants, however, has not been investigated. Here, antisense suppression of CP12 in tobacco (Nicotiana tabacum) was observed to impact on NAD-induced PRK and GAPDH complex formation but had little effect on enzyme activity. Additionally, only minor changes in photosynthetic carbon fixation were observed. Despite this, antisense plants displayed changes in growth rates and morphology, including dwarfism and reduced apical dominance. The hypothesis that CP12 is essential to separate oxidative pentose phosphate pathway activity from Calvin-Benson cycle activity, as proposed in cyanobacteria, was tested. No evidence was found to support this role in tobacco. Evidence was seen, however, for a restriction to malate valve capacity, with decreases in NADP-malate dehydrogenase activity (but not protein levels) and pyridine nucleotide content. Antisense repression of CP12 also led to significant changes in carbon partitioning, with increased carbon allocation to the cell wall and the organic acids malate and fumarate and decreased allocation to starch and soluble carbohydrates. Severe decreases were also seen in 2-oxoglutarate content, a key indicator of cellular carbon sufficiency. The data presented here indicate that in tobacco, CP12 has a role in redox-mediated regulation of carbon partitioning from the chloroplast and provides strong in vivo evidence that CP12 is required for normal growth and development in plants.</jats:p

    Starch Granule Re-Structuring by Starch Branching Enzyme and Glucan Water Dikinase Modulation Affects Caryopsis Physiology and Metabolism

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    Starch is of fundamental importance for plant development and reproduction and its optimized molecular assembly is potentially necessary for correct starch metabolism. Re-structuring of starch granules in-planta can therefore potentially affect plant metabolism. Modulation of granule micro-structure was achieved by decreasing starch branching and increasing starch-bound phosphate content in the barley caryopsis starch by RNAi suppression of all three Starch Branching Enzyme (SBE) isoforms or overexpression of potato Glucan Water Dikinase (GWD). The resulting lines displayed Amylose-Only (AO) and Hyper-Phosphorylated (HP) starch chemotypes, respectively. We studied the influence of these alterations on primary metabolism, grain composition, starch structural features and starch granule morphology over caryopsis development at 10, 20 and 30 days after pollination (DAP) and at grain maturity. While HP showed relatively little effect, AO showed significant reduction in starch accumulation with re-direction to protein and β-glucan (BG) accumulation. Metabolite profiling indicated significantly higher sugar accumulation in AO, with re-partitioning of carbon to accumulate amino acids, and interestingly it also had high levels of some important stress-related metabolites and potentially protective metabolites, possibly to elude deleterious effects. Investigations on starch molecular structure revealed significant increase in starch phosphate and amylose content in HP and AO respectively with obvious differences in starch granule morphology at maturity. The results demonstrate that decreasing the storage starch branching resulted in metabolic adjustments and re-directions, tuning to evade deleterious effects on caryopsis physiology and plant performance while only little effect was evident by increasing starch-bound phosphate as a result of overexpressing GWD
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