Study on the formation and anti-biofilm properties of cinnamon essential oil inclusion complexes by the structure of modified ß-cyclodextrins.

Essential oils (EOs), which are plant-oriented anti-biofilm agents, are extensively encapsulated by cyclodextrins to overcome their aqueous solubility and chemical instability, and achieve slow release during long-term storage. However, the biological activities of EOs decreased after initial encapsulation in CDs. In this study, modified-ß-cyclodextrins (ß-CDs) were screened as wall materials to maintained the initial anti-biofilm effect of pure CEO. The inhibitory and bactericidal activities of CEO encapsulated in five types of ß-CDs with different substituents (primary hydroxyl, maltosyl, hydroxypropyl, methyl, and carboxymethyl) against Staphylococcus aureus biofilm were evaluated. Crystal violet assay and 3D-View observations suggested that CEO and its inclusion complexes (CEO-ICs) inhibited Staphylococcus aureus biofilm formation through the inhibition of colonising spreading, exopolysaccharide synthesis, and cell surface properties. Molecular docking revealed the causes of the decrease in the anti-biofilm effect after encapsulation, and quantitative structure-activity relationship assays provided MIC and MBIC prediction equation for modified-ß-cyclodextrins inclusion complexes. Maltosyl-ß-CD was screened as the best wall material to retained the anti-biofilm activities as pure cinnamon essential oil in initial stage, and its inclusion complexes can effectively inhibited biofilm formation in milk. This study provides a theoretical guidance for the selection ß-CDs to encapsulate CEO as plant-oriented anti-biofilm agents to inhibit bacterial biofilm formation.

Economizing Socialist Aid: China's Failed Surgical Plant in Algeria, 1973-80.

China is currently a source of technology for the developing world, yet little is known about its transfer of modern technologies before the 1980s liberalization. This article excavates a failed surgical turn-key project that China planned in the mid-1970s at Médéa in state socialist Algeria. The case of South-South collaboration analyzes how three principles-simplification, economization, and improvement of labor efficiency-dominated the negotiations and design process. The Chinese aspired to transfer technology suiting Algeria, but were restricted by capital input, technological capacity, and the pragmatism of convenience, as well as a distorted vision of Algerians' needs. This article puts Chinese industrial aid into perspective within the history of appropriate technology, examining the asymmetries in perceptions, interests, and priorities that sank this early attempt at South-South cooperation. By uncovering the often-neglected perspective of Chinese aid technocrats, it also breaks the stereotype of Maoist China ignoring cost effectiveness in its foreign aid.