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

Bulge- and Basal Layer-Specific Expression of Fibroblast Growth Factor-13 (FHF-2) in Mouse Skin

A variety of polypeptide growth factors are involved in the dynamic maintenance of the skin and hair. Here, we demonstrate the presence of high levels of fibroblast growth factor (FGF)-13 in the bulge region of hair follicles. Using real-time PCR, we found that expression of FGF-13 mRNA is comparable to, or higher than, that of other FGF known to regulate hair growth and wound healing. To gain additional insight into the function of FGF-13, we evaluated its distribution using in situ hybridization and immunohistochemical staining. Unlike other FGF, the distribution of FGF-13 mRNA and protein in adult mice was mainly restricted to cells in the bulge region of hair follicles, although lower levels were detected with less frequency in keratinocytes in the basal layer of the epidermis. FGF-13 protein was detectable in the bulge region throughout the hair growth cycle, but its distribution was especially wide during telogen and early anagen. During hair follicle morphogenesis in newborn mice, FGF-13 protein was first detected in the bulge region and basal layer keratinocytes 3 d after birth. These findings suggest that FGF-13 may play a role in regulating the function of cells in the bulge region and basal layer of the epidermis

Shifting Between Cognitive and Visual Distraction: The Impact of Cognitive Ability on Distraction Caused by Secondary Tasks

We conducted an experiment in order to investigate impacts of centralexecutive (CE) functions and modality of secondary task presentation in a dualtaskexperiment. We found that shifting ability, out of three major CE functions(inhibition, shifting, and updating) was particularly important in determiningwhether primary (pedal-tracking) task performance was better in the presence ofauditory, vs. visual, presentation of the secondary task