Impact of turbulence intensity and fragmentation velocity on dust particle size evolution and non-ideal magnetohydrodynamics effects

We investigate the influence of dust particle size evolution on non-ideal magnetohydrodynamic effects during the collapsing phase of star-forming cores, taking both the turbulence intensity in the collapsing cloud core and the fragmentation velocity of dust particles as parameters. When the turbulence intensity is small, the dust particles do not grow significantly, and the non-ideal MHD effects work efficiently in high-density regions. The dust particles rapidly grow in a strongly turbulent environment, while the efficiency of non-ideal MHD effects in such an environment depends on the fragmentation velocity of the dust particles. When the fragmentation velocity is small, turbulence promotes coagulation growth and collisional fragmentation of dust particles, producing small dust particles. In this case, the adsorption of charged particles on the dust particle surfaces becomes efficient and the abundance of charged particles decreases, making non-ideal MHD effects effective at high densities. On the other hand, when the fragmentation velocity is high, dust particles are less likely to fragment, even if the turbulence is strong. In this case, the production of small dust particles become inefficient and non-ideal MHD effects become less effective. We also investigate the effect of the dust composition on the star and disk formation processes. We constrain the turbulence intensity of a collapsing core and the fragmentation velocity of dust for circumstellar disk formation due to the dissipation of the magnetic field.Comment: Accepted for publication in MNRAS. 15 pages, 13 figure

Dust coagulation and fragmentation in a collapsing cloud core and their influence on non-ideal magnetohydrodynamic effects

We determine the time evolution of the dust particle size distribution during the collapse of a cloud core, accounting for both dust coagulation and dust fragmentation, to investigate the influence of dust growth on non-ideal magnetohydrodynamic effects.The density evolution of the collapsing core is given by a one-zone model. We assume two types of dust model: dust composed only of silicate (silicate dust) and dust with a surface covered by $\mathrm{H_{2}O}$ ice ($\mathrm{H_{2}O}$ ice dust). When only considering collisional coagulation, the non-ideal magnetohydrodynamic effects are not effective in the high-density region for both the silicate and $\mathrm{H_{2}O}$ ice dust cases. This is because dust coagulation reduces the abundance of small dust particles, resulting in less efficient adsorption of charged particles on the dust surface. For the silicate dust case, when collisional fragmentation is included, the non-ideal magnetohydrodynamic effects do apply at a high density of $n_{\mathrm{H}}>10^{12} \ \mathrm{cm^{-3}}$because of the abundant production of small dust particles. On the other hand, for the$\mathrm{H_{2}O}$ice dust case, the production of small dust particles due to fragmentation is not efficient. Therefore, for the$\mathrm{H_{2}O}$ice dust case, non-ideal magnetohydrodynamic effects apply only in the range$n_{\mathrm{H}}\gtrsim 10^{14} \ \mathrm{cm^{-3}}$, even when collisional fragmentation is considered. Our results suggest that it is necessary to consider both dust collisional coagulation and fragmentation to activate non-ideal magnetohydrodynamic effects, which should play a significant role in the star and disk formation processes.Comment: Accepted for publication in MNRAS. 17 pages, 11 figure

Measurement of intracellular pH by flow cytometry using pH sensitive fluorescence dye, and influence of hyperthermia and amiloride derivatives on the intracellular pH

エールリッヒ腹水癌細胞とそのアドリアマイシン耐性細胞において蛍光pH指示薬2'、7'-bis-(2-carboxyethyl) carboxyfluorescein] (BCECF) の蛍光量をフローサイトメトリーで測定することによって細胞内pHの検量曲線を作成することができた。このことより、これらの細胞においてBCECFの蛍光量で細胞内pHの変化を簡易に比較できることを示唆した。さらに、温熱、Na(+)/H(+) exchanger の阻害例であるアミロライド[3,5-diamino-6-chloro-N-(diaminomethylene) pyrazinecarboxamide]、およびアミロライド誘導隊MH-12-43[N-amidino-3-amino-6-chloro-5-(N-ethyliso-propylamino) pyrazinecarboxyamide] の細胞内pHへの影響をエールリッヒ腹水癌細胞で観察した。37℃では、0.5mMアミロライド、0.05mM　MH-12-43により細胞内pHは減少し、42℃処理によりさらに減少した。42℃において、0.05mM　MH-12-43による細胞内pHの減少は、0.5mMアミロライドによる減少より大きかった。We examined relationship between intensity of intracellular fluorescence of [2', 7'-bis-(2'-carboxyethyl) carboxyfluorescein] (BCECF) and intracellular pH in Ehrlich ascites tumor cells and their adriamycin-resistant strain, and found a good correlation between them at both strains. This suggests that changes in the intracellular pH on these strains may be obtained through measurement of intracellular fluorescence of BCECF by flow cytometry. Further, we examined influence of hyperthermia, 3, 5-diamino-6-chloro-N-(diaminomethylene)pyrazinecarboxamide (amiloride), an inhibitor of Na(+)/H(+) exchanger, and its derivative; N-amidino-3-amino-6-chloro-5-(N-ethylisopropylamino) pyrazinecarboxyamide (MH-12-43) on the intracellular pH in Ehrlich ascites tumor cells. The treatment of 0.5mM amiloride or 0.05mM MH-12-43 reduced intracellular pH at 37℃, while the more reduction was observed by the treatment at 42℃. The reduction of intracellular pH by 0.05mM MH-12-43 was more substantial than that of 0.5mM amiloride at 42℃

Mouse Embryonic Stem Cells Inhibit Murine Cytomegalovirus Infection through a Multi-Step Process

In humans, cytomegalovirus (CMV) is the most significant infectious cause of intrauterine infections that cause congenital anomalies of the central nervous system. Currently, it is not known how this process is affected by the timing of infection and the susceptibility of early-gestational-period cells. Embryonic stem (ES) cells are more resistant to CMV than most other cell types, although the mechanism responsible for this resistance is not well understood. Using a plaque assay and evaluation of immediate-early 1 mRNA and protein expression, we found that mouse ES cells were resistant to murine CMV (MCMV) at the point of transcription. In ES cells infected with MCMV, treatment with forskolin and trichostatin A did not confer full permissiveness to MCMV. In ES cultures infected with elongation factor-1α (EF-1α) promoter-green fluorescent protein (GFP) recombinant MCMV at a multiplicity of infection of 10, less than 5% of cells were GFP-positive, despite the fact that ES cells have relatively high EF-1α promoter activity. Quantitative PCR analysis of the MCMV genome showed that ES cells allow approximately 20-fold less MCMV DNA to enter the nucleus than mouse embryonic fibroblasts (MEFs) do, and that this inhibition occurs in a multi-step manner. In situ hybridization revealed that ES cell nuclei have significantly less MCMV DNA than MEF nuclei. This appears to be facilitated by the fact that ES cells express less heparan sulfate, β1 integrin, and vimentin, and have fewer nuclear pores, than MEF. This may reduce the ability of MCMV to attach to and enter through the cellular membrane, translocate to the nucleus, and cross the nuclear membrane in pluripotent stem cells (ES/induced pluripotent stem cells). The results presented here provide perspective on the relationship between CMV susceptibility and cell differentiation

HAMAMATSU-ICG study: Protocol for a phase III, multicentre, single-arm study to assess the usefulness of indocyanine green fluorescent lymphography in assessing secondary lymphoedema

Introduction Secondary lymphoedema of the extremities is an important quality-of-life issue for patients who were treated for their malignancies. Indocyanine green (ICG) fluorescent lymphography may be helpful for assessing lymphoedema and for planning lymphaticovenular anastomosis (LVA). The objective of the present clinical trial is to confirm whether or not ICG fluorescent lymphography using the near-infrared monitoring camera is useful for assessing the indication for LVA, for the identification of the lymphatic vessels before the conduct of LVA, and for the confirmation of the patency of the anastomosis site during surgery. Methods and analysis This trial is a phase III, multicentre, single-arm, open-label clinical trial to assess the efficacy and safety of ICG fluorescent lymphography when assessing and treating lymphoedema of patients with secondary lymphoedema who are under consideration for LVA. The primary endpoint is the identification rate of the lymphatic vessels at the incision site based on ICG fluorescent lymphograms obtained before surgery. The secondary endpoints are 1) the sensitivity and specificity of dermal back flow determined by ICG fluorescent lymphography as compared with 99mTc lymphoscintigraphy—one of the standard diagnostic methods and 2) the usefulness of ICG fluorescent lymphography when confirming the patency of the anastomosis site after LVA. Ethics and dissemination The protocol for the study was approved by the Institutional Review Board of each institution. The trial was filed for and registered at the Pharmaceuticals and Medical Devices Agency in Japan. The trial is currently on-going and is scheduled to end in June 2020