Liquid Crystalline Gelation of DNA

学位記番号：工博甲33

Structural and kinetic modification of aqueous hydroxypropylmethylcellulose(HPMC) induced by electron beam irration

Electron beam was irradiated on 10% and 20% hydroxypropylmethylcellulose (HPMC) aqueous solutions with different doses to make gel films. As increasing dose, the gel fraction of the film increased sharply above a critical dose and then decreased gradually after passing a maximum. The scission/cross-linking ratio and the critical dose were determined using the Charlesby-Rosiak equation as 0.52 and 9 kGy for 10% gel and 0.43 and 14 kGy for 20% gel, respectively. The gel fraction for 20% HPMC film was lower at low dose and higher at high dose than that for 10% film. The behavior of the swelling ratio of the gel film was just opposite to that of the gel fraction. The cross-linking density of the gel estimated from the Flory theory linearly increased with irradiation dose at low dose, passed a maximum around 100 and 160 kGy for 10% and 20% films, respectively, and decreased at high dose. These results suggest the competition of scission and cross-linking induced by indirect effect of irradiation. Dielectric relaxation measurement by time domain reflectometry and RF impedance/material analyzer revealed two characteristic relaxations of chain motions around 100MHz and of orientation of free water around 20GHz. From the dose dependence of the relaxation parameters determined by fitting to a combined equation of Cole-Cole type and KWW type, a coupling of motions of HPMC molecules and water molecules was strongly suggested. The critical dose for gelation was coincident with the dose for the maximum of t h and the minimum of Deh together with the minimum of t m and the maximum of Dem, where t h and Deh denote the relaxation time and the relaxation strength for free water molecular motion and t m and Dem the corresponding ones for HPMC molecular motion. The characteristic behavior was discussed in terms of the increase of affinity between HPMC and water and the constrained molecular motion in the gel network

Nanometer-sized gelatin particles prepared by means of gamma-ray irradiation

Nanometer-sized gelatin particles have been prepared by means of gamma-ray irradiation and characterized by static and dynamic light scattering combined with circular dichroism measurements. The molecular weight of the nanoparticles was much larger than that of the original gelatin molecules, whereas the hydrodynamic radius was much smaller. Radius of gyration evaluated from the angular dependence of the static light scattering intensity decreased with increasing irradiation dose. Circular dichroism spectra of the gelatin nanoparticles were independent of temperature, and it is suggested that the nanoparticles consist of highly and randomly packed gelatin and their conformation is stable against the temperature change

JAK inhibition ameliorates bone destruction by simultaneously targeting mature osteoclasts and their precursors

Background: Rheumatoid arthritis (RA) is characterized by chronic inflammation and resultant cartilage/bone destruction because of aberrantly activated osteoclasts. Recently, novel treatments with several Janus kinase (JAK) inhibitors have been shown to successfully ameliorate arthritis-related inflammation and bone erosion, although their mechanisms of action for limiting bone destruction remain unclear. Here, we examined the effects of a JAK inhibitor on mature osteoclasts and their precursors by intravital multiphoton imaging. Methods: Inflammatory bone destruction was induced by local injection of lipopolysaccharides into transgenic mice carrying reporters for mature osteoclasts or their precursors. Mice were treated with the JAK inhibitor, ABT-317, which selectively inhibits the activation of JAK1, and then subjected to intravital imaging with multiphoton microscopy. We also used RNA sequencing (RNA-Seq) analysis to investigate the molecular mechanism underlying the effects of the JAK inhibitor on osteoclasts. Results: The JAK inhibitor, ABT-317, suppressed bone resorption by blocking the function of mature osteoclasts and by targeting the migratory behaviors of osteoclast precursors to the bone surface. Further exhaustive RNA-Seq analysis demonstrated that Ccr1 expression on osteoclast precursors was suppressed in the JAK inhibitor-treated mice; the CCR1 antagonist, J-113863, altered the migratory behaviors of osteoclast precursors, which led to the inhibition of bone destruction under inflammatory conditions. Conclusions: This is the first study to determine the pharmacological actions by which a JAK inhibitor blocks bone destruction under inflammatory conditions; this inhibition is beneficial because of its dual effects on both mature osteoclasts and immature osteoclast precursors.Yari S., Kikuta J., Shigyo H., et al. JAK inhibition ameliorates bone destruction by simultaneously targeting mature osteoclasts and their precursors. Inflammation and Regeneration 43, 18 (2023); https://doi.org/10.1186/s41232-023-00268-4

Reagent-free crosslinking of aqueous gelatin : manufacture and characteristics of gelatin gels irradiated with gamma-ray and electron beam

This is an Author's Accepted Manuscript of an article published in include the complete citation information for the final version of the artcle as published in the Journal of Biomaterials Science, Polymer Edition, 2003-11, copyright Taylor & Francis, available online at: http://www.tandfonline.com/10.1163/15685620332255343

Subaru Hyper Suprime-Cam Survey for An Optical Counterpart of GW170817

We perform a $z$-band survey for an optical counterpart of a binary neutron star coalescence GW170817 with Subaru/Hyper Suprime-Cam. Our untargeted transient search covers $23.6$ deg$^2$ corresponding to the $56.6\%$ credible region of GW170817 and reaches the $50\%$ completeness magnitude of $20.6$ mag on average. As a result, we find 60 candidates of extragalactic transients, including J-GEM17btc (a.k.a. SSS17a/DLT17ck). While J-GEM17btc is associated with NGC 4993 that is firmly located inside the 3D skymap of GW170817, the other 59 candidates do not have distance information in the GLADE v2 catalog or NASA/IPAC Extragalactic Database (NED). Among 59 candidates, 58 are located at the center of extended objects in the Pan-STARRS1 catalog, while one candidate has an offset. We present location, $z$-band apparent magnitude, and time variability of the candidates and evaluate the probabilities that they are located inside of the 3D skymap of GW170817. The probability for J-GEM17btc is $64\%$ being much higher than those for the other 59 candidates ($9.3\times10^{-3}-2.1\times10^{-1}\%$). Furthermore, the possibility, that at least one of the other 59 candidates is located within the 3D skymap, is only $3.2\%$. Therefore, we conclude that J-GEM17btc is the most-likely and distinguished candidate as the optical counterpart of GW170817.Comment: 14 pages, 9 figures. Accepted for publication in PASJ (Publications of the Astronomical Society of Japan

マスウキブクロセンチュウ(新称)Salvelinema salmonicolaの新宿主と新分布地

広島県西部を流れる太田川水系の筒賀川とその支流である猪股川においてアマゴ(Oncorhynchus masou ishikawae Jordan and McGregor)の鰾から線虫類のSalvelinema salmonicola (Ishii, 1916)を採集した。アマゴは本線虫の新宿主である。今回の採集によって, 北海道から滋賀県の範囲にあった我が国での本種の分布域は広島県にまで拡大した。本記録により, 広島県のサケ科魚類から記録された寄生虫は6種, 太田川水系のサケ科魚類から得られた寄生虫は3種となる。採集地におけるヨコエビ類を中間宿主とする本種の生活環について考察するとともに, 河川工事が終宿主や中間宿主, 本種に与える影響について論議した。本種とSalvelinema属の両者にマスウキブクロセンチュウ(鱒鰾線虫)の新標準和名を提唱する。The cystidicolid nematode Salvelinema salmonicola (Ishii, 1916) is a parasite of freshwater salmonids in the North Pacific rim region, including Japan, Far Eastern Russia, Alaska (USA) and northern British Columbia (Canada). This species was found in the swim bladder of river-resident amago salmon (Oncorhynchus masou ishikawae Jordan and McGregor)(Salmoniformes: Salmonidae) from the Tsutsuga River and its tributary, Inomata River, of the Ota River System in Hiroshima Prefecture, western Honshu, Japan. This is the first record of S. salmonicola from western Japan, extending its distribution from central to western Honshu in the country. Oncorhynchus masou ishikawae is a new host for S. salmonicola. The life cycle of S. salmonicola and the impact of the past and current construction on the fish definitive host, invertebrate (probably amphipod) intermediate host and parasite populations in the sampling locality are discussed