168 research outputs found
Structure of inert layer 4He adsorbed on a mesoporous silica
We have studied the structure of inert layer 4He adsorbed on mesoporous
silica (FSM-16), by the vapor pressure and heat capacity measurements. The heat
capacity shows a Schottky-like peak due to the excitation of a part of
localized solid to fluid. We analyzed the heat capacity over a wide temperature
region based on the model including the contribution of the localized solid and
excited fluid and clarified that the excited fluid coexists with the localized
solid at high temperature. As the areal density approaches the value at which
superfluid appears (n_C), the fluid amount is likely to go to zero, suggesting
a possibility that the inert layer is solidified just below n_C
Solidification of 4He confined in a nanometer-size channel
Solidification of 4He confined in a one-dimensional 2.8-nm channel of FSM was studied by pressure and heat capacity measurements. It was found that the freezing pressure in the channel is greatly elevated and is between 3.3 and 3.8 MPa at absolute zero. Furthermore, the density change at the liquid-solid transition is evaluated. The decrease in the molar volume is less than 1×10−2 cm3/mol at the transition of 4 MPa, which is about two orders of magnitude smaller than that of bulk. From this observation, we can conclude that solid 4He confined in the channel has a density as low as liquid
Dynamical superfluid response of 4He confined in a nanometer-size channel
We have studied the superfluid response of liquid 4He confined in a one-dimensional nanometer-size channel by means of a twofold torsional oscillator at 2000 and 500 Hz. For the lower-frequency mode, both the superfluid onset and the dissipation peak shift to the low-temperature side by 40 mK under 0.13 MPa, and the shift is slightly enhanced by the application of pressure. The strong frequency dependence indicates that the superfluid response is a dynamical phenomenon. Furthermore, this dependence is consistent with the theoretical prediction based on the Tomonaga-Luttinger liquid model
Superfluidity of liquid 4He confined to one-dimensional straight nanochannel structures
Superfluidity of liquid 4He confined in one-dimensional (1D) nanometer-size channels has been studied by means of a torsional oscillator. When the channel is larger than 2.8 nm in diameter, liquid 4He becomes superfluid at low temperatures and a dissipation due to quantized vortex is observed. The superfluid onset temperature is 1.8 K at 0.14 MPa for the 4.7 nm channel and 0.89 K at 0.01 MPa for the 2.8 nm channel. For the latter, it is suppressed strongly under the application of pressure, and continuously approaches zero at around 2.1 MPa at absolute zero, which suggests a quantum phase transition between the superfluid and nonsuperfluid states in the 1D channel
Superfluidity and BEC of liquid 4He confined in a nanometer-size channel
We have studied the heat capacity and superfluidity of liquid 4He confined in a uniform and straight nanometer-size channel. The heat capacity of liquid 4He in the channel has a bend at a certain temperature TB; below this temperature a small amount of the superfluid fraction appears. This means that 4He atoms enter a BEC-like low-entropy state below TB. Additionally, the superfluid fraction showed a second growth far below TB under low pressure, accompanied by the dissipation. This two-stage growth is possibly a feature of the quasi-one-dimensional system
Ultrasound study of the mass decoupling of 4He inert films on mesoporous silica
We performed ultrasound measurements for 4He films adsorbed on a mesoporous silica. We observed a large decrease in sound velocity with increasing temperature, accompanied by an attenuation peak. The observed dependence of the sound velocity on temperature is well explained by a thermally activated relaxation process. The magnitude of the change in sound velocity is comparable to that due to the total mass loading of 4He, suggesting that the mass decoupling occurs at low temperature
Laminin γ1 C-terminal Glu to Gln mutation induces early postimplantation lethality
Daiji Kiyozumi, Yukimasa Taniguchi, Itsuko Nakano, Junko Toga, Emiko Yagi, Hidetoshi Hasuwa, Masahito Ikawa, and Kiyotoshi Sekiguchi, "Laminin γ1 C-terminal Glu to Gln mutation induces early postimplantation lethality", Life Science Alliance, Vol.1, No.5, e201800064, Life Science Alliance, 201
A case of axillary lymphadenitis caused by Mycobacterium intracellulare in an immunocompetent patient
Axillary lymphadenitis caused by non-tuberculous mycobacteria is rare and has been reported in immunocompromised hosts. Herein, we report the case of a 67-year-old man without immunodeficiency who developed right axillary lymphadenitis caused by Mycobacterium intracellulare and showed a small nodular shadow in the left pulmonary apex. Biopsy of the right axillary lymph node revealed several epithelioid granulomas, and the culture of the lymph node aspirate yielded Mycobacterium intracellulare. The lymph node lesion and left lung apex shadow resolved spontaneously after careful outpatient monitoring. This case suggests that axillary lymphadenitis could be caused by Mycobacterium intracellulare in an immunocompetent patient
Mechanical homeostasis of liver sinusoid is involved in the initiation and termination of liver regeneration
Organogenesis and regeneration are fundamental for developmental progress and are associated with morphogenesis, size control and functional properties for whole-body homeostasis. The liver plays an essential role in maintaining homeostasis of the entire body through various functions, including metabolic functions, detoxification, and production of bile, via the three-dimensional spatial arrangement of hepatic lobules and has high regenerative capacity. The regeneration occurs as hypertrophy, which strictly controls the size and lobule structure. In this study, we established a three-dimensional sinusoidal network analysis method and determined valuable parameters after partial hepatectomy by comparison to the static phase of the liver. We found that mechanical homeostasis, which is crucial for organ morphogenesis and functions in various phenomena, plays essential roles in liver regeneration for both initiation and termination of liver regeneration, which is regulated by cytokine networks. Mechanical homeostasis plays critical roles in the initiation and termination of organogenesis, tissue repair and organ regeneration in coordination with cytokine networks
- …