Histochemical demonstration of acid mucopolysaccharide production by tissue cultured epithelial-like cells

Summary The production of mucopolysaccharides by human epithelial-like cells in vitro has been studied using histochemical techniques. Cells of the human amnion F/L line were grown for 12–14 days in Leighton tubes containing cover slips which were fixed and stained by the Hale, PAS, toluidine blue and alcian blue stains and techniques. Control slides were treated with active and heat inactivated solutions of testicular and bacterial hyaluronidase and chondroitinase prior to staining. Results indicated that material stainable by all the techniques employed was elaborated by the amnion cells and this was partially removable by various combinations of polysaccharases. It is concluded that epithelial-like cells can synthesize and elaborate the ground substance components, hyaluronic acid, chondroitin sulphates and unidentified polysaccharide complexes, in much the same manner as mesenchymal cells and thus contribute to the maintenance of epithelial integrity by de novo production of intercellular substances.Supported by USPHS Grants No. 991 and DE-01681, T01-DE00108 National Institute of Dental Research, National Institutes of Health and the National Health and Medical Research Council, Australia.     

Consequential LCA and LCC using linear programming: an illustrative example of biorefineries

Purpose

This paper aims to demonstrate how LCA can be improved by the use of linear programming (LP) (i) to determine the optimal choice between new technologies, (ii) to identify the optimal region for supplying the feedstock, and (iii) to deal with multifunctional processes without specifying a certain main product. Furthermore, the contribution of LP in the context of consequential LCA and LCC is illustrated.

Methods

We create a mixed integer linear program (MILP) for the environmental and economic assessment of new technologies. The model is applied in order to analyze two residual beech wood-based biorefinery concepts in Germany. In terms of the optimal consequences for the system under study, the principle of the program is to find a scaling vector that minimizes the life cycle impact indicator results of the system. We further transform the original linear program to extend the assessment by life cycle costing (LCC). Thereby, two multi-objective programming methods are used, weighted goal programming and epsilon constraint method.

Results and discussion

The consequential case studies demonstrate the possibility to determine optimal locations of newly developed technologies. A high number of potential system modifications can be studied simultaneously without matrix inversion. The criteria for optimal choices are represented by the objective functions and the additional constraints such as the available feedstock in a region. By combining LCA and LCC targets within a multi-objective programming approach, it is possible to address environmental and economic trade-offs in consequential decision-making.

Conclusions

This article shows that linear programming can be used to extend standard LCA in the field of technological choices. Additional consequential research questions can be addressed such as the determination of the optimal number of new production plants and the optimal regions for supplying the resources. The modifications of the program by additional profit requirements (LCC) into a goal program and Pareto optimization problem have been identified as promising steps toward a comprehensive multi-objective LCSA.