Development of SPring-8 vacuum system

SPring-8 storage ring has been available for user operation with low emittance and extreme stability for over 10 years. However there occurred some problems in the components of the storage ring due to high-brightness synchrotron radiation (SR) and low-emittance operation. On the vacuum system of the storage ring, an accurate pressure could not be measured near the photon absorber due to scattered high-energy SR to the gauge head. High-energy SR activated dissolved oxygen in cooling water, and the activated dissolved oxygen corroded the inside of the photon absorbers in SR irradiation part. Air leakage occurred at an injection chamber due to impact by a small-size electron beam produced by low-emittance operation.We investigated the cause of the aforementioned difficulties with the vacuum system and prescribed the treatments described in this paper. In addition, we are making continual efforts at further system upgrades such as developing an RF shield that suppresses temperature increase in the shield in possible high-current operation.     

Moisture Proofing of Spray Dried Particles Comprising Ammonium Nitrate/Potassium Nitrate/Polymer

The aim of this study was to fabricate moisture‐proof, phase‐stabilized, ammonium nitrate/potassium nitrate (AN/PN) particles, with a polymer used as the moisture‐proofing agent. The particles were prepared with a spray drying technique. Water solutions (or water dispersions) containing AN/PN and one of five different types of polymer were spray‐dried, which produced white powders with particle diameters of approximately 20–40 μm. Scanning electron microscopy and energy‐dispersive X‐ray spectroscopy indicated that each component was homogeneously distributed throughout the particles. The particles exhibited little aggregation compared to the reagent AN, even when left for 7 d or more. In addition, the moisture absorption of the particles at less than 40 % relative humidity (RH) was lower than that of the polymer‐free particles. Even under high‐moisture conditions (83 % RH), the particles did not deliquesce immediately, and they retained their original shape for 30–60 min, whereas the polymer‐free particles were transformed into droplets within 5 min.     

Development of a compact efficient 10 Hz 20 TW Ti:sapphire laser system with a 1 kHz regenerative amplifier

We have constructed a compact efficient Ti:sapphire laser system that generates 30 fs, 630 mJ pulses at a repetition rate of 10 Hz. A new geometry for a single-stage multipass power amplifier is proposed that greatly weakens and even makes use of thermal lensing. Such geometry can realize high output in a single-stage power amplifier; otherwise at least two-stage power amplifiers are required. The new configuration simplifies the laser system and reduces the cost. The key point in this design is that the beam spot size evolution is considered in combination with the pulse amplification.     

Phylogenetic classification of Pseudomonas putida strains by MALDI-MS using ribosomal subunit proteins as biomarkers

A new method for phylogenetic classification of bacterial strains using matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS) is proposed. This method was developed using a bioinformatics-based approach to the rapid identification of bacteria as previously proposed by Demirev and co-workers, which uses ribosomal proteins composed of approximately 50 subunit proteins as biomarkers. Although the amino acid sequences of ribosomal proteins are highly conserved, slight sequence variations can occur at the strain level. Since ribosomal subunit proteins are a complex of housekeeping proteins that have different phylogenetic evolution rates, sequence variation detected as mass differences by MALDI-MS may be useful for the phylogenetic classification of bacteria at strain level. In our proposed method, the first step is the selection of reliable biomarkers through characterization of the expressed ribosomal subunit proteins of a reference strain (usually a genome-sequenced strain) by MALDI-MS. The observed masses in the MALDI mass spectra of cell lysates of sample strains are then compared with the biomarker masses of the reference strain. The biomarkers for each sample strain were designated as present or absent at the reference masses, indicated by 1 or 0, respectively, which were summarized in a table. This table is processed by cluster analysis, generating a phylogenetic tree. In this study, the success of this approach was confirmed by classification of Pseudomonas putida strains because its classification is much more complicated than that of other bacterial strains. Forty-three reliable biomarkers were selected from ribosomal sub-unit proteins of a genome-sequenced strain, P. putida KT2440. The numbers and kinds of biomarkers observed for 16 strains of P. putida, including different biovars, were markedly different, reflecting the variety of the strains. The classification results by the proposed method were highly comparable to those based on the DNA gyrase subunit B gene (gyrB) sequence analysis, suggesting our proposed method would be a useful high-throughput method for phylogenetic classification of newly isolated bacteria.     

Condensed Phase Behavior in the Combustion of Ammonium Dinitramide

This paper reports on the thermal and combustion behaviors of ammonium dinitramide (ADN). The thermal behavior is measured by a pressure thermogravimetric analysis (TGA) at pressures below 8 MPa. The burning rates of pure ADN and ADN/ammonium nitrate (AN) mixtures are measured in the range 0.2–12 MPa, and the burning temperature profiles are obtained using thermocouples with diameters of 5 and 25 μm. This report mainly focuses on the condensed‐phase behavior in the vicinity of a burning surface. The temperature profiles are complicated because the ADN decomposition and AN dissociation compete during the condensed phase, and the bubbles of the decomposition gas and gas‐phase flame also affect the surface temperature. AN addition helps to understand the effects of AN during the condensed phase, and it was shown that the burning temperature rises to the critical temperature of AN. Based on these experimental results, the pressure dependency of the burning rates is also discussed.     

Role of Additives in the Combustion of Ammonium Dinitramide

The thermal decomposition behavior and combustion characteristics of mixtures of ammonium dinitramide (ADN) with additives were studied. Micrometer‐sized particles of Al, Fe₂O₃, TiO₂, NiO, Cu(OH)NO₃, copper, CuO, and nanometer‐sized particles of aluminum (Alex) and CuO (nano‐CuO) were employed. The thermal decomposition was measured by TG‐DTA and DSC. The copper compounds and NiO lowered the onset temperature of ADN decomposition. The heat value of ADN with Alex was larger than that of pure ADN in closed conditions. The burning rates and temperature of the pure ADN and ADN/additives mixtures were measured. CuO and NiO enhance the burning rate, particularly at pressures lower than 1 MPa, because of the catalyzed decomposition in the condensed phase; the other additives lower the burning rate. This negative effect on the burning rate is explained based on the surface temperature measurements by a physicochemical mechanism, which involves a chemical reaction, a phase change of the ammonium nitrate, and the blown‐off droplets of the condensed phase.     

Improvement of a temperature response function for divertor heat flux monitoring in fusion devices

Temperature response functions have been developed to investigate sensor design and divertor heat flux estimation in magnetically confined plasmas. The time-dependent heat flux can be derived by fitting the response function to experimental thermocouple(TC) data. Because the TC signals have a time delay to transit events such as discharge start or confinement transition, the time delay is taken into account in a temperature response function. Such a function accurately describes the signal from ...     

Reactivation of Anticancer Immunity by Resetting Interorgan Crosstalk in Immune-Suppressive Cells with a Nanoparticulated Anti-Inflammatory Drug

The reactivation of anticancer immunity is a fundamental principle in cancer immunotherapy as evidenced by the use of immune checkpoint inhibitors (ICIs). While treatment with the ICIs is shown to have remarkable and durable therapeutic effects in the responders, the low objective response rate (<40%) continues to be a major problem. Since myeloid-derived suppressor cells (MDSCs), heterogenous cells with strong immunosuppressive activity that originate in the hematopoietic system, suppress the anticancer immunity via parallel immune checkpoint-dependent and independent pathways, these cells are potential targets for improving the efficacy of cancer immunotherapy. In this study, it is demonstrated that MDSCs can be depleted by delivering synthetic glucocorticoid dexamethasone to phagocytic cells in the spleen using a lipid nanoparticle. Since the interaction of nanoparticles with T cells is intrinsically poor, this strategy also enables the “detargeting” from T cells, thus avoiding the nonspecific suppression of cytotoxic immune responses against cancer cells. In addition to the direct anticancer effect of the nanoparticulated dexamethasone, their synergistic anticancer effect with ICIs is also reported.