A collagen network phase improves cell seeding of open-pore structure scaffolds under perfusion

Scaffolds with open-pore morphologies offer several advantages in cell-based tissue engineering, but their use is limited by a low cell seeding efficiency. We hypothesized that inclusion of a collagen network as filling material within the open-pore architecture of polycaprolactone-tricalcium phosphate (PCL-TCP) scaffolds increases human bone marrow stromal cells (hBMSC) seeding efficiency under perfusion and in vivo osteogenic capacity of the resulting constructs. PCL-TCP scaffolds, rapid prototyped with a honeycomb-like architecture, were filled with a collagen gel and subsequently lyophilized, with or without final crosslinking. Collagen-free scaffolds were used as controls. The seeding efficiency was assessed after overnight perfusion of expanded hBMSC directly through the scaffold pores using a bioreactor system. By seeding and culturing freshly harvested hBMSC under perfusion for 3 weeks, the osteogenic capacity of generated constructs was tested by ectopic implantation in nude mice. The presence of the collagen network, independently of the crosslinking process, significantly increased the cell seeding efficiency (2.5-fold), and reduced the loss of clonogenic cells in the supernatant. Although no implant generated frank bone tissue, possibly due to the mineral distribution within the scaffold polymer phase, the presence of a non crosslinked collagen phase led to in vivo formation of scattered structures of dense osteoids. Our findings verify that the inclusion of a collagen network within open morphology porous scaffolds improves cell retention under perfusion seeding. In the context of cell-based therapies, collagen-filled porous scaffolds are expected to yield superior cell utilization, and could be combined with perfusion-based bioreactor devices to streamline graft manufacture.

Molecular Structure of the mineral woodhouseite CaAl3(PO4,SO4)2(OH)6

The mineral woodhouseite CaAl3(PO4,SO4)2(OH)6 is a hydroxy phosphate-sulphate mineral belonging to the beudantite subgroup of alunites, and has been characterised by Raman spectroscopy, complimented with infrared spectroscopy. Bands at various wavenumbers were assigned to the different vibrational modes of woodhouseite, which were then associated to the molecular structure of the mineral. Bands were primarily assigned to phosphate and sulphate stretching and bending modes. Two symmetric stretching modes for both phosphate and sulphate supported the concept of non-equivalent phosphate and sulphate units in the mineral structure. Bands in the OH stretching region enabled hydrogen bond distances to be calculated.

An indication that non-informative vision eliminates the Kinaesthetic Fusion Effect

This study investigated the Kinaesthetic Fusion Effect (KFE) first described by Craske and Kenny in 1981. The current study did not replicate these findings. Participants did not perceive any reduction in the sagittal separation of a button pressed by the index finger of one arm and a probe touching the other, following repeated exposure to the tactile stimuli present on both unseen arms. This study’s failure to replicate the widely-cited KFE as described by Craske et al. (1984) suggests that it may be contingent on several aspects of visual information, especially the availability of a specific visual reference, the role of instructions regarding gaze direction, and the potential use of a line of sight strategy when referring felt positions to an interposed surface. In addition, a foreshortening effect was found; this may result from a line-of-sight judgment and represent a feature of the reporting method used. The transformed line of sight data were regressed against the participant reported values, resulting in a slope of 1.14 (right arm) and 1.11 (left arm), and r > 0.997 for each. The study also provides additional evidence that mis-perceptions of the mediolateral position of the limbs specifically their separation and consistent with notions of Gestalt grouping, is somewhat labile and can be influenced by active motions causing touch of one limb by the other. Finally, this research will benefit future studies that require participants to report the perceived locations of the unseen limbs.

Constructability improvement in sea water intake structure

Purpose The purpose of this paper is to explore the process, and analyse the implementation of constructability improvement and innovation result during the planning and design for sea water intake structure of fertilizer plant project. Design/methodology/approach The research methodology approach is case study method at project level. This constructability improvement process was investigated by using constructability implementation check lists, direct observation, documented lesson learned analysis and key personnel interviews. Findings The case study shows that the implementation of constructability during planning and design stage for this sea water intake structure has increased the project performance as well as improved the schedule by 5 months (14.21%) and reduced the project cost by 15.35%. Research limitations/implications This case study was limited to three (3) previous sea water intake projects as references and one (1) of new method sea water intake structure at fertilizer plant project. Practical implications A constructability improvement check list using theory and lesson learned for the specific construction project was documented. Originality/value The findings support the relevant study of constructability and provide specific lesson learned for three (3) previous project and one (1) of the new innovation method of the construction project and documented by the company.