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Blood vessel damage resulting from trauma or diseases presents a serious risk of morbidity and mortality. Although synthetic vascular grafts have been successfully commercialized for clinical use, they are currently only readily available for large-diameter vessels (>6 mm). Small-diameter vessel (<6 mm) replacements, however, still present significant clinical challenges worldwide. The primary objective of this study is to create novel, tunable, small-diameter blood vessels with biomimetic two distinct cell layers [vascular endothelial cell (VEC) and vascular smooth muscle cell (VSMC)] using an advanced coaxial 3D-bioplotter platform. Specifically, the VSMCs were laden in the vessel wall and VECs grew in the lumen to mimic the natural composition of the blood vessel. First, a novel bioink consisting of VSMCs laden in gelatin methacryloyl (GelMA)/ polyethylene(glycol)diacrylate/alginate and lyase was designed. This specific design is favorable for nutrient exchange in an ambient environment and simultaneously improves laden cell proliferation in the matrix pore without the space restriction inherent with substance encapsulation. In the vessel wall, the laden VSMCs steadily grew as the alginate was gradually degraded by lyase leaving more space for cell proliferation in matrices. Through computational fluid dynamics simulation, the vessel demonstrated significantly perfusable and mechanical properties under various flow velocities, flow viscosities, and temperature conditions. Moreover, both VSMCs in the scaffold matrix and VECs in the lumen steadily proliferated over time creating a significant two-cell-layered structure. Cell proliferation was confirmed visually through staining the markers of alphasmooth muscle actin and cluster of differentiation 31, commonly tied to angiogenesis phenomena, in the vessel matrices and lumen, respectively. Furthermore, the results were confirmed quantitatively through gene analysis which suggested good angiogenesis expression in the blood vessels. This study demonstrated that the printed blood vessels with two distinct cell layers of VECs and VSMCs could be potential candidates for clinical small-diameter blood vessel replacement applications.

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Sun, H., Nelson, M., Chen, F. and Husch, J. 2009. Soil mineral structural water loss during loss on ignition analyses. Can. J. Soil Sci. 89: 603Á610. Water loss from soil minerals has been known to cause errors in the determination of soil organic matter when the loss on ignition (LOI) method is used. Unfortunately, no known published studies reliably quantify the range of structural water in the soil. To do this, 15 common reference minerals were analyzed by LOI to obtain their individual water loss. In addition, 14 upland, loamy soil samples and 3 wetland/hydric soil samples with varied mineral contents were analyzed to collect their X-ray powder diffraction spectra. Based upon X-ray spectra peak intensities, the modal abundance of minerals in each soil sample was determined using the RockJock computer program. The resultant modal weight percentages of all identified minerals in each soil sample were then multiplied by the LOI value for each mineral to obtain the mineral structural water loss (SWL) of that soil sample. For the 17 soil samples analyzed, the range of mineral water loss is 0.56 to 2.45%. Depending on the LOI values of the soil samples, the SWL:LOI ratios range from 0.04 to around 1.00. The SWL:LOI ratios are particularly low for top wetland soil when the LOI value is higher. The ratios are lower for surface soil samples than for subsurface soil samples because of the high LOI values in surface soil samples. Understanding soil mineral water loss and its relation to the LOI patterns from various environments is important for the accurate evaluation of soil organic matter when the LOI method is used.Key words: Mineral, structural water, loss on ignition Sun, H., Nelson, M., Chen, F. et Husch, J. 2009. Perte structurelle d'eau par les mine´raux du sol lors des analyses de perte par calcination. Can. J. Soil Sci. 89: 603Á610. On sait que l'eau perdue par les mine´raux du sol cause des erreurs lorsqu'on s'efforce de calculer la quantite´de matie`re organique dans le sol par la me´thode d'analyse de perte par calcination (LOI). Malheureusement, aucune des e´tudes publie´es ne quantifie de manie`re fiable la variation de l'eau structurelle dans le sol. Pour y reme´dier, les auteurs ont analyse´15 mine´raux de re´fe´rence communs par la LOI afin d'en mesurer la perte d'eau. Ils ont aussi analyse´14 e´chantillons de sol loameux des plateaux et 3 e´chantillons de sol hydrique des terres humides afin de recueillir le spectre de leur poudre par diffraction des rayons X. En partant de l'intensite´des pics obtenus aux rayons X, ils ont e´tabli l'abondance modale des mine´raux dans chaque e´chantillon graˆce au logiciel RockJock. Les pourcentages modaux ponde´re´s des mine´raux identifie´s dans chaque e´chantillon qui en re´sultent ont ensuite e´te´multiplie´s par la valeur LOI de chaque mine´ral, ce qui a donne´la perte structurelle d'eau (SWL) du mine´ral pour l'e´chantillon. Sur les 17 e´chantillons examine´s, la perte d'eau des mine´raux varie de 0,56 % a`2,45 %. D'apre`s la valeur LOI des e´chantillons, le ...