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Neural crest cells are multipotent cells that delaminate from the neuroepithelium, migrating to distant destinations throughout the embryo. Aberrant migration has severe consequences, such as congenital disorders. While animal models have improved our understanding of neural crest anomalies, the in vivo contributions of actin-based protrusions are still poorly understood. Here, we demonstrate that murine neural crest cells use lamellipodia and filopodia in vivo. Using neural crest-specific knockouts or inhibitors, we show that the serine-threonine kinase, Glycogen Synthase Kinase-3 (GSK3), and the cytoskeletal regulator, Lamellipodin (Lpd), are required for lamellipodia formation whilst preventing focal adhesion maturation. We consequently identified Lpd as a novel substrate of GSK3 and found that phosphorylation of Lpd favours Lpd interactions with the Scar/WAVE complex (lamellipodia formation) at the expense of Ena/VASP protein interactions (adhesion maturation and filopodia formation). All together, we provide an improved understanding of cytoskeletal regulation in mammalian neural crest migration, which has general implications for neural crest anomalies and cancer.

The total artificial heart (TAH) requires physiological control to respond to the metabolic demand of the body. To date, 1/R control is a single physiological control method that can control venous pressure. To realize an implantable 1/R control system, we are developing a new pressure measuring method using absolute pressure sensor. To find a method for absolute pressure sensor, which went well without calibration, concept of left atrial pressure (LAP) estimation using its pulsatile amplitude was proposed. Its possibility was investigated with two long-term survived goats whose hearts were replaced with the helical flow TAHs. In manual control condition, there existed a positive relation between mean LAP (mLAP) and normalized pulsatile amplitude (NPA). Percent systole revealed not to affect the relationship between mLAP and NPA. Dispersion was observed between different pulse rates. As for cardiac output difference (QLD) that is the difference of flow rate between systolic and diastolic phases, similar results were obtained except in low QLDs. In the 1/R control condition, relatively high correlation between mLAP and NPA could be obtained. In estimation of mLAP using the correlating function of individual goat, fairly good correlation was obtained between measured mLAP and estimated mLAP. Despite that further studies are necessary, it was demonstrated that the concept of the LAP estimation could be possible.

The model of horn antenna was built. The radiation field of the antenna was simulated and used as the incident wave. The influence of the distance between target and antenna as well as the antenna beam on the near-field scattering characteristic was studyed from near-field RCS and angular glint. The result was compared with the far field condition's. The results show that when the antenna is near the target, the incident wave cannot be regarded as plane wave and the effects of the antenna pattern on near-field scattering cannot be ignored. The scanning of antenna beam leads to the change of the target illuminated area and it has great influence on the near-field scattering characteristic.

The objectives of this study were to find an appropriate method and process for treating ma bamboo (Dendrocalamus latiflorus) with a chromium-free copper-phosphorous salt (CuP). The effects of the constituent ratios and concentrations of CuP as well as treatment conditions on the green colour protection were investigated. In addition, accelerated UV light fastness tests, indoor exposure tests, and outdoor weathering tests were also carried out to evaluate the colour fastness and durability of bamboo culms. The results demonstrated that an attractive green colour was obtained by treating ma bamboo with 1% CuP at 60 C for 3 h, using a 60:40 ratio of CuSO4 to H3PO4 in an aqueous solution. Compared with untreated bamboo culms, the CuP-treated samples had the brighter greenish skin and also provided better green colour fastness. After 180 days of indoor exposure, the a* value was slightly increased from 5.8 to 5.4. # 2002 Elsevier Science Ltd. All rights reserved.

The helical flow pump (HFP) was invented to be an ideal pump for developing the TAH and the helical flow TAH (HFTAH) using two HFPs has been developed. However, since the HFP is quite a new pump, hydrodynamic characteristics inside the pump are not clarified. To analyze hydrodynamic characteristics of the HFP, flow visualization study using the particle image velocimetry and computational fluid dynamics analysis were performed. The experimental and computational models were developed to simulate the left HFP of the HFTAH and distributions of flow velocity vectors, shear stress and pressure inside the pump were examined. In distribution of flow velocity vectors, the vortexes in the vane were observed, which indicated that the HFP has a novel and quite unique working principle in which centrifugal force rotates the fluid in the helical volutes and the fluid is transferred from the inlet to the outlet helical volutes according to the helical structure. In distribution of shear stress, the highest shear stress that was considered to be occurred by the shunt flow across the impeller was found around the entrance of the inlet helical volute. However, it was not so high to cause hemolysis. This shunt flow is thought to be improved by redesigning the inlet and outlet helical volutes. In distribution of pressure, negative pressure was found near the entrance of the inlet helical volute. However, it was not high. Negative pressure is thought to be reduced with an improvement in the design of the impeller or the vane shape.

The present control method used in our helical flow total artificial heart (HFTAH) would only need four parameters. Nowadays, gauge pressure sensors are being used to obtain the pressure needed for control parameters. Nevertheless, there are also many following problems such as calibration, maintenance, offset drift and infection due to the skin-penetrative lines for the usage of gauge pressure sensor. Therefore, it is preferable to find another substitutional way instead of the gauge sensor to measure the pressure. In addition, with an eye to completing an implantable HFTAH, we would like to do without any lines through the experiment animal. Therefore, it was confirmed in this study that whether there is a relation between the left atrial pressure (LAP) and its pulse pressure (amplitude). Subsequently the mean value of LAP and its amplitude were quantified. There are two methods used in this study to process the data. Method one, frequency spectrum analysis, is to quantify the signals by getting the absolute value of amplitude for a fixed heartbeat analysis. Method two, by using the synchronous detection method, it is postulated to be more applicable to variant heartbeat data with 1/R control. By the relation of LAP and the pulse pressure acquired in the above two methods, as long as the amplitude of LAP is known by the absolute pressure sensor, it's able to obtain the mean value of LAP (for it suggests a linear relation). Therefore the characteristic could substitute one of the control parameter (that is the LAP), and the other three parameters will be acquired by estimation thus it doesn't need to measure them additionally. Consequently, it is expected that acquiring LAP by absolute pressure sensor for one of the control parameters could attain to an implantable HFTAH.

The helical flow pump (HFP) is newly developed blood pomp for total artificial heart (TAH). HFP can work with lower rotational speed than axial and centrifugal blood pump. It can be seen reasonable feature to generate pulsatile flow because high response performance can be realized. In this article, pulsatility of HFP was evaluated using mock circulation loop. Pulsatile flow was generated by modulating the rotational speed in various amplitude and heart rate. In the experiment, relationship between Pump flow, pump head, rotational speed amplitude, heart rate and power consumption is evaluated. As the result, complete pulsatile flow with mean flow rate of 5 L/min and mean pressure head of 100 mmHg can be obtained at ± 500 rpm with mean rotational speed of 1378 to 1398 rpm in hart rate from 60 to 120. Flow profiles which are non-pulsatile, quasi-pulsatile or complete flow can be adjusted arbitrarily. Therefore, HFP has excellent pulsatility and control flexibility of flow profile.