Hiroshima University

About: Hiroshima University is a education organization based out in Hiroshima, Japan. It is known for research contribution in the topics: Population & Cancer. The organization has 33602 authors who have published 69290 publications receiving 1495648 citations. The organization is also known as: Hiroshima Daigaku.

Predicting the Gas Diffusion Coefficient in Undisturbed Soil from Soil Water Characteristics

Abstract: The gas diffusion coefficient in soil (D P ), and its dependency on soil physical characteristics, governs the diffusive transport of oxygen, greenhouse gases, fumigants, and volatile organic pollutants in agricultural, forest, and urban soils. Accurate models for predicting Dp as a function of air-filled porosity (e) in natural, undisturbed soil are needed for realistic gas transport and fate simulations. Using data from 126 undisturbed soil layers, we obtained a high correlation (r 2 = 0.97) for a simple, nonlinear expression describing D P at -100 cm H 2 O of soil water potential (D P,100 ) as a function of the corresponding air-filled porosity (e 100 ), equal to the volume of soil pores with an equivalent pore diameter >30 μm. A new D P (e) model was developed by combining the D P,100 (e 100 ) expression with the Burdine relative hydraulic conductivity model, the latter modified to predict relative gas diffusivity in unsaturated soil. The D P,100 and Burdine terms in the D P (e) model are both related to the soil water characteristic (SWC) curve and, thus, the actual pore-size distribution within the water content range considered. The D P (e) model requires knowledge of the soil's air-filled and total porosities and a minimum of two points on the SWC curve, including a measurement at -100 cm H 2 O. When tested against independent gas diffusivity data for 21 differently textured and undisturbed soils, the SWC-dependent D P (e) model accurately predicted measured data and gave a reduction in root mean square error of prediction between 58 and 83% compared to the classical, soil type-independent Penman and Millington-Quirk models. To further test the new D P (e) model, gas diffusivity and SWC measurements on undisturbed soil cores from three 0.4-m soil horizons (sandy clay loam, sandy loam, and loamy sand) within the 4 to 7 m depth below an industrially polluted soil site were carried out. For these deep subsurface soils the SWC-dependent model best predicted the measured gas diffusivities.

Development of a high-speed multifingered hand system and its application to catching

Abstract: In this paper we introduce a newly developed high-speed multi-fingered robotic hand. The hand has 8-joints and 3-fingers. A newly developed small harmonic drive gear and a high-power mini actuator are fitted in each finger link, and a strain gauge sensor is in each joint. The weight of the hand module is only 0.8 kg, but high-speed motion and high-power grasping are possible. The hand can close its joints at 180 deg per 0.1 s, and the fingertips have an output force of about 28 N. The hand system is controlled by a massively parallel vision system. Experimental results are shown in which a falling object was caught by the high-speed hand.

Mesenchymal stem cells enhance growth and metastasis of colon cancer.

Abstract: Recently, mesenchymal stem cells (MSCs) were reported to migrate to tumor stroma as well as injured tissue. We examined the role of human MSCs in tumor stroma using an orthotopic nude mice model of KM12SM colon cancer. In in vivo experiments, systemically injected MSCs migrated to the stroma of orthotopic colon tumors and metastatic liver tumors. Orthotopic transplantation of KM12SM cells mixed with MSCs resulted in greater tumor weight than did transplantation of KM12SM cells alone. The survival rate was significantly lower in the mixed-cell group, and liver metastasis was seen only in this group. Moreover, tumors resulting from transplantation of mixed cells had a significantly higher proliferating cell nuclear antigen labeling index, significantly greater microvessel area and significantly lower apoptotic index. Splenic injection of KM12SM cells mixed with MSCs, in comparison to splenic injection of KM12SM cells alone, resulted in a significantly greater number of liver metastases. MSCs incorporated into the stroma of primary and metastatic tumors expressed α-smooth muscle actin and platelet-derived growth factor receptor-β as carcinoma-associated fibroblast (CAF) markers. In in vitro experiments, KM12SM cells recruited MSCs, and MSCs stimulated migration and invasion of tumor cells through the release of soluble factors. Collectively, MSCs migrate and differentiate into CAFs in tumor stroma, and they promote growth and metastasis of colon cancer by enhancing angiogenesis, migration and invasion and by inhibiting apoptosis of tumor cells.