From Legal Transplants to Sustainable Transition

Extended producer responsibility (EPR), which assigns significant responsibility to producers to take back their end‐of‐life products to create incentives for redesign of products with lower life cycle environmental impacts, has come to a crossroad facing a trade‐off between the original innovation‐oriented regime design and the cost‐efficiency challenges in practice. This is particularly true in its implementation in non‐Organization for Economic Co‐operation and Development (OECD) countries as they are trying to transplant the “best practices” from OECD countries, for there is increasing skepticism as to whether EPR is suitable for developing countries at all. As an important producer of electronic products and destination of electronic waste (e‐waste) flows in the world, China has been expected to play a vital role in the evolution of global governance based on the idea of EPR, either to create new ways for producers to perform their end‐of‐life strategies, or to reshape the mode of production and consumption with its fast‐growing market. However, the establishment of EPR in China has been long and full of difficulties. This article reviews the status and trends in the establishment of an EPR system for waste electrical and electronic equipment (WEEE) management in China. We use the framework of a multilevel perspective of transition theory in our analysis to characterize the complex interactions among various agents in the evolution of the Chinese system from initial innovation‐oriented design to the current efficiency‐oriented version. An ongoing research framework for evaluation of the EPR program in China is outlined as the research agenda in coming years.     

Surface Properties and Corrosion Behavior of Co–Cr Alloy Fabricated with Selective Laser Melting Technique

We sought to study the corrosion behavior and surface properties of a commercial cobalt–chromium (Co–Cr) alloy which was fabricated with selective laser melting (SLM) technique. For this purpose, specimens were fabricated using different techniques, such as SLM system and casting methods. Surface hardness testing, microstructure observation, surface analysis using X-ray photoelectron spectroscopy (XPS) and electrochemical corrosion test were carried out to evaluate the corrosion properties and surface properties of the specimens. We found that microstructure of SLM specimens was more homogeneous than that of cast specimens. The mean surface hardness values of SLM and cast specimens were 458.3 and 384.8, respectively; SLM specimens showed higher values than cast ones in hardness. Both specimens exhibited no differences in their electrochemical corrosion properties in the artificial saliva through potentiodynamic curves and EIS, and no significant difference via XPS. Therefore, we concluded that within the scope of this study, SLM-fabricated restorations revealed good surface properties, such as proper hardness, homogeneous microstructure, and also showed sufficient corrosion resistance which could meet the needs of dental clinics.     

Changes in arbuscular mycorrhizal fungus community along an exotic plant Eupatorium adenophorum invasion in a chinese secondary forest

Knowledge of the changes in arbuscular mycorrhizal (AM) fungi is fundamental for understanding the success of exotic plant invasions in natural ecosystems. In this study, AM fungal colonization and spore community were examined along an invasive gradient of the exotic plant Eupatorium adenophorum in a secondary forest in southwestern China. With increasing E. adenophorum invasion, the density of arbuscules in the roots of E. adenophorum significantly increased, but the AM root colonization rate and the densities of vesicles and hyphal coils in roots of E. adenophorum were not significantly different. A total of 29 AM fungi belonging to nine genera were identified based on spore morphology. Claroideoglomus etunicatum, Funneliformis geosporus, and Glomus aggregatum were the most common AM fungal species. The E. adenophorum invasion significantly decreased the AM fungal spore density in the soil. Furthermore, with increasing of E. adenophorum invasion the spore densities of C. etunicatum, G. aggregatum, and G. arenarium significantly decreased, whereas F. geosporus significantly increased. Nonmetric multidimensional scaling demonstrated that the AM fungus community composition was significantly different (P=0.003) in the different invasive levels of E. adenophorum, and significantly correlated with plant species richness, soil total P, and soil NO₃ ^?-N. The results suggest that the alteration in AM fungus community might be caused by E. adenophorum invasion via changing the local plant community and soil properties in a Chinese secondary forest ecosystem.     

Design,synthesis, and biological evaluation of novel substituted thiourea derivatives as potential anticancer agents for NSCLC by blocking K-Ras protein-effectors interactions

Abstract

Mutation of the proto-oncogene K-Ras is one of the most common molecular mechanisms in non-small cell lung cancer. Many drugs for treating lung cancer have been developed, however, due to clinical observed K-Ras mutations, corresponding chemotherapy and targeted therapy for such mutation are not efficient enough. In this study, on the basis of the crystal structure of K-Ras, 21 analogues (TKR01–TKR21) containing urea or thiourea were rationally designed, which can effectively inhibit the lung cancer cell A549 growth. The designing of these compounds was based on the structure of K-Ras protein, and the related groups were replaced by bioisosteres to improve the affinity and selectivity. Biological testing revealed that compound TKR15 could significantly inhibit the proliferation of A549 cell with IC₅₀ of 0.21?µM. Docking analysis showed that the TKR15 can effectively bind to the hydrophobic cavity and form a hydrogen bond with the Glu37. In addition, through flow apoptosis assay and immunofluorescence staining assay, it confirmed that this compound can inhibit A549 cell proliferation with the mechanism of blocking K-Ras^G12V protein and effector proteins interactions through the apoptotic pathway. In conclusion, our studies in finding novel potent compound (TKR15) with confirmed mechanism showed great potential for further optimisation and other medicinal chemistry relevant studies.     

Rapid methods of detecting the target molecule in immunohistology using a bioluminescence probe

We demonstrate a novel rapid direct detection method for immunohistochemistry, using a bioluminescent probe. An anti‐CEA antibody‐fused far‐red bioluminescent protein can monitor the accumulation of this type of probe in tumour tissues. The bimodal spectrum (λ_max = 460 and 675 nm) of this bioluminescent probe is extremely stable under different conditions of pH and ion concentration. The sensitivity of our bioluminescent labelling was at the same level of enzymatic labelling, e.g. peroxidase, as an indirect system. Our novel technique is simple and can shorten the pretreatment time of paraffin sections to around 30 min. The utility of our bioluminescent labelling covers all imaging in vitro, in vivo and ex vivo, suggesting that our antibody‐fused bioluminescent probe has the potential to detect tumour antigens with a high sensitivity in routine immune histological examinations. Copyright © 2012 John Wiley & Sons, Ltd.     

Studies of the Pharmacokinetics and Toxicology of 2′,3′-Dideoxy-β-L-5-fluorocytidine (β-L-FddC) and 2′,3′-Dideoxy-β-L-cytidine (β-L-ddC) In Vivo; and Synthesis and Antiviral Evaluations of 2′,3′-Dideoxy-β-L-5-azacytidine

Abstract

The pharmacokinetics and toxicology of 2′,3′-dideoxy-β-L-5-fluorocytidine (β-L-FddC) and 2′,3′-dideoxy-β-L-cytidine (β-L-ddC) in mice was investigated. In addition, 2′,3′-dideoxy-β-L-5-azacytidine (β-L-5-aza-ddC) and its α-L-anomer (α-L-5-aza-ddC) were synthesized by coupling the silylated 5-azacytosine derivative with 1-O-acetyl-5-O-(tert-butyldimethylsilyl)-2,3-dideoxy-L-ribofuranose, followed by separation of the α-and β-anomers and were evaluated in vitro against HBV and HIV. β-L-5-aza-ddC was found to show significant anti-HBV activity at approximately the same level as 2′,3′-dideoxy-β-D-cytidine (ddC), which is a known anti-HBV agent. β-L-5-aza-ddC was not cytotoxic to L1210, P388, S-180, and CCRF-CEM cells up to a concentration of 100 μ. Conversely, the α-L-anomer was not active against HBV at the same concentration.