The global optimization of molecular clusters is an important topic encountered in many fields of chemistry. In our previous work (Phys. Chem. Chem. Phys., 2015, 17, 24173), we successfully applied the recently introduced artificial bee colony (ABC) algorithm to the global optimization of atomic clusters and introduced the corresponding software "ABCluster". In the present work, ABCluster was extended to the optimization of clusters of rigid molecules. Here "rigid" means that all internal degrees of freedom of the constituent molecules are frozen. The algorithm was benchmarked by TIP4P water clusters (H2O)N (N ≤ 20), for which all global minima were successfully located. It was further applied to various clusters of different chemical nature: 10 microhydration clusters, 4 methanol microsolvation clusters, 4 nonpolar clusters and 2 ion-aromatic clusters. In all the cases we obtained results consistent with previous experimental or theoretical studies.

Bicycles are a desirable form of transportation for many reasons, including the fact that taking a bicycle is environmentally-friendly, economically cost-effective, a way to keep fit and healthy and, on occasions, an enjoyable social activity. This paper explores the characteristics and commonalities between particular bike-sharing systems in urban areas, with a view to deriving influences on the sustainability of such systems. The empirical study is China and the paper analyses bike-sharing systems in five Chinese cities. China is suffering from the severe negative consequences of high private vehicle usage in large and densely populated cities. Nevertheless a long history of bicycle usage in the country provides great potential for such a green form of travel to be part of public and private transportation.The findings show that bike-sharing systems have varying degrees of success. The configurations which seem the most sustainable consider and integrate elements relating to transport planning, system design and choice of business model. Key conclusions are that those responsible for developing policy and practices in relation to bike-sharing systems need to understand the diverse aspects of value for the stakeholders wishing to engage with such a system. Public bicycle sharing, as a Product Service System, needs to be carefully developed to appreciate the quality and timely interplay between the physical design of the system and the provision of services being offered.

Laminins, the main components of basement membranes, are heterotrimers consisting of α, β, and γ polypeptide chains linked together by disulfide bonds. Laminins-1 and -2 are both composed of β1 and γ1 chains and differ from each other on their α chain, which is α1 and α2 for laminin-1 and -2, respectively. The present study shows that whereas laminins-1 and -2 are synthesized in the mouse developing lung and in epithelial–mesenchymal cocultures derived from it, epithelial and mesenchymal monocultures lose their ability to synthesize the laminin α1 chain. Synthesis of laminin α1 chain however returns upon re-establishment of epithelial–mesenchymal contact. Cell–cell contact is critical, since laminin α1 chain is not detected in monocultures exposed to coculture-conditioned medium or in epithelial–mesenchymal cocultures in which heterotypic cell–cell contact is prevented by an interposing filter. Immunohistochemical studies on cocultures treated with brefeldin A, an inhibitor of protein secretion, indicated both epithelial and mesenchymal cells synthesize laminin α1 chain upon heterotypic cell– cell contact. In a set of functional studies, embryonic lung explants were cultured in the presence of monoclonal antibodies to laminin α1, α2, and β/γ chains. Lung explants exposed to monoclonal antibodies to laminin α1 chain exhibited alterations in peribronchial cell shape and decreased smooth muscle development, as indicated by low levels of smooth muscle α actin and desmin. Taken together, our studies suggest that laminin α1 chain synthesis is regulated by epithelial–mesenchymal interaction and may play a role in airway smooth muscle development.