Biliary sludge in dogs is dismissed commonly as an incidental finding. On the other hand, gallbladder mucocele is reported increasingly in dogs and can lead to biliary obstruction or gallbladder rupture. Cholestasis is suspected to play a role in development of sludge and mucoceles, though there are no data in dogs to support this. We investigated gallbladder emptying, a key factor in biliary flow, in dogs with mobile sludge, immobile sludge, or gallbladder mucocele and in healthy controls. Gallbladder ejection fraction estimated by ultrasonography was used as the index of gallbladder emptying. The ejection fraction at 60 min after eating was significantly decreased in all three abnormal groups. Moreover, all dogs with sludge or a mucocele had gallbladder distension. These changes were the greatest in the mucocele group. Thus, biliary stasis occurs not only in dogs with gallbladder mucocele but also in dogs with biliary sludge. Cholestasis may play a role in the pathogenesis or progression of these diseases in dogs.

We propose a new mechanism which can lead to ferromagnetism in Hubbard models containing triangles with different on-site energies. It is based on an effective Hamiltonian that we derive in the strong coupling limit. Considering a one-dimensional realization of the model, we show that in the quarter-filled, insulating case the ground-state is actually ferromagnetic in a very large parameter range going from Tasaki's flat-band limit to the strong coupling limit of the effective Hamiltonian. This result has been obtained using a variety of analytical and numerical techniques. Finally, the same results are shown to apply away from quarter-filling, in the metallic case.

This paper reports on a microelectromechanical systems (MEMS)-based sensor for pulse wave measurement. The sensor consists of an air chamber with a thin membrane and a 300-nm thick piezoresistive cantilever placed inside the chamber. When the membrane of the chamber is in contact with the skin above a vessel of a subject, the pulse wave of the subject causes the membrane to deform, leading to a change in the chamber pressure. This pressure change results in bending of the cantilever and change in the resistance of the cantilever, hence the pulse wave of the subject can be measured by monitoring the resistance of the cantilever. In this paper, we report the sensor design and fabrication, and demonstrate the measurement of the pulse wave using the fabricated sensor. Finally, measurement of the pulse wave velocity (PWV) is demonstrated by simultaneously measuring pulse waves at two points using the two fabricated sensor devices. Furthermore, the effect of breath holding on PWV is investigated. We showed that the proposed sensor can be used to continuously measure the PWV for each pulse, which indicates the possibility of using the sensor for continuous blood pressure measurement.

This paper reports on a method to directly measure the contractile forces of cardiomyocytes using MEMS (micro electro mechanical systems)-based force sensors. The fabricated sensor chip consists of piezoresistive cantilevers that can measure contractile forces with high frequency (several tens of kHz) and high sensing resolution (less than 0.1 nN). Moreover, the proposed method does not require a complex observation system or image processing, which are necessary in conventional optical-based methods. This paper describes the design, fabrication, and evaluation of the proposed device and demonstrates the direct measurements of contractile forces of cardiomyocytes using the fabricated device.

This paper reports on a method for evaluating the force-length relationship of adhering human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) on the substrate using a measurement system comprising of a micromachined movable plate and a piezoresistive force probe. The cells on the plate are stretched by pushing the movable plate with the piezoresistive cantilever, which is actuated by a piezo stage. The twitch forces and the applied stretch are measured quantitatively with the piezoresistive cantilever. The results demonstrated that the twitch forces of the hiPSC-CMs increased when a stretch was applied. This evaluation method improves the understanding of the intrinsic force-length relationship of hiPSC-CMs at the cellular scale.