E-waste management in developing countries through legislation and regulations: a case study of China

E-waste is an emerging issue driven by the rapidly increasing quantities, the hazards involved and the valuable materials in it. Due to a lack of environmentally sound technologies or equipment and the imperfect e-waste management system, the poor quality e-waste recycling and disposal methods commonly practiced in developing countries now have serious and hazardous effects on the environment and the workers'/residents' health. Additionally, industrialized countries are exporting increasing quantities of e-waste to developing countries, complicating the situation finther. The environmental and health issues caused by e-waste in developing countries have resulted in the search for solutions to address this problem before it becomes worse. The main purpose of this research is to find how legislation and regulations be used to improve management of e-waste in developing countries especially studying a case in China on e-waste management, which is a very helpful example to other developing countries which are also facing the same e-waste'issue. A case study methodology was used in this research. To collect data, semi-structured interviews with officers or experts from key relevant government departments/institutions involved in e-waste management/regulation, from electronic appliance producers, from customers at different levels of the value chain, as well as direct and non-participant observations were carried out in six cities of China. For another perspective, the review of relevant departmental documents/publications was also carried out to multiply the source of data. In this case study the analysis relies largely on qualitative data and interpretive methods, applied to what was found in interviews/observations and what is written down in documents/ literatures. The research found that lack of systernatic and enforceable law and regulations has become the most serious obstacle in the e-waste management system and limited the effective control of e-waste in developing countries. Developing subsidiary regulations and standards could support the enforcement of the main national law and regulations on e-waste management and it could farther urge the development of local regulations to improve the enforceýbility of the national law and regulations. Identifying the principal administrative department and coordinating the cooperation of various departments could avoid the duplication of administrative functions among government departments. It is important to construct monitoring systems to supervise the enforcement of the regulations and construct the standards and registration system to qualify the e-waste recycling and disposal enterprises, the secondhand market of electronic products and the regenerative resources market of reusable materials in ewaste. The economic differences made it possible to formulate special regulations for economically backward areas compared to the, more advanced areas even within one country. Improving the existing e-waste recovery system and regulating the payment system according to the local economic conditions for e-waste recycling and disposal could improve the integrated management of e-waste. Producers as well as government and even consumers should be responsible for e-waste together. The government needs to continuously strengthen regulatory systems to ensure that the huge economic benefits from the e-waste recycling industry are not overshadowed by the negative impact on the workers'/residents' welfare and overall environmental sustainability

Regulating for e-waste in China: progress and challenges

Electronic waste (e-waste) is an emerging issue in the municipal towns of China. Its significance is driven by the rapidly increasing quantities, the hazards involved and the valuable materials in it. The poor quality e-waste recycling and disposal methods commonly practised in China have serious and hazardous effects on the environment and on the health of workers and residents. Additionally, industrialised countries are exporting increasing quantities of e-waste to China, complicating the situation further. The Chinese government needs to strengthen regulatory systems to ensure that the huge economic benefits from the e-waste recycling industry are not overshadowed by the negative impact on welfare and overall environmental sustainability. In response to the growing concern on e-waste, the government and other policy-making agencies in China are continuously strengthening the legislative and institutional framework for regulating importation and industrial activities in e-waste recycling and disposal. This paper provides a situational analysis and discusses the basic elements of the existing legislative framework for e-waste management in China. The paper concludes with an analysis of opportunities and challenges that exist in improving the enabling/regulatory environment for a hazardous but valuable commodity in a fast-growing economy

Enantioselective Physiological Effects of the Herbicide Diclofop on Cyanobacterium <i>Microcystis aeruginosa</i>

Water blooms caused by cyanobacteria are currently major global environmental issues. The outbreaks induced by nutrient elements have attracted much attention; however, the effects of environmental pollutants on the cyanobacteria are themselves poorly understood, especially those due to chiral chemicals. To explore the enantioselective eco-effects of the chiral herbicide diclofop-methyl (DM) and its major metabolite diclofop acid (DA), the physiological characteristics of <i>Microcystis aeruginosa</i> were investigated. The results showed that using both biomass and protein content as growth parameters is necessary to access the impact of the herbicides, that stimulation biomass production by <i>R</i>-DA and <i>S</i>-DA was apparent (nonessential), and that the concentration of 5 mg/L is worth noting. Ultrastructure changes in gas vacuoles, thylakoids, glycogen, cyanophycin granules, poly beta-hydroxybutyrate, polyhedral body, and lipids indicated different toxicity modes among the four chemicals. The different effects between <i>R</i>-DA and <i>S</i>-DA demonstrated that <i>R</i>-DA probably acts as a proton ionophore shuttling protons across the plasmalemma, whereas <i>S</i>-DA did not demonstrate such action. The toxicity order in the present study is <i>S</i>-DA < <i>R</i>-DA < DM < DA. Stimulation of the growth of <i>M. aeruginosa</i> during the first 3 days by herbicidally inactive <i>S</i>-DA was greater than that due to <i>R</i>-DA, which is adverse to water quality in water bodies. Therefore, using the herbicidally active <i>R</i>-enantiomer is recommended. These results are helpful in understanding the enantioselective effects of chiral pesticides on cyanobacteria, which is important for environmental assessment and protection. It is also helpful for guiding the application of chiral pesticides in agricultural settings

Effect of Ca²⁺ Ion and Temperature on Association of Thermally Sensitive PAA-<i>b</i>-PNIPAM Diblock Chains in Aqueous Solutions

Poly­(<i>tert</i>-butyl acrylate)-<i>b</i>-poly­(<i>N</i>-isopropylacrylamide) (PtBA-<i>b</i>-PNIPAM) was first synthesized by sequential reversible addition–fragmentation chain transfer polymerization of <i>tert</i>-butyl acrylate and <i>N</i>-isopropylacrylamide. Its hydrolysis led to amphiphilic poly­(acrylic acid)-<i>b</i>-poly­(<i>N</i>-isopropylacrylamide) (PAA-<i>b</i>-PNIPAM) that can form micelles in aqueous solutions at temperatures higher than 37 °C because PNIPAM is a thermally sensitive polymer. In the presence of Ca²⁺, the complexation between one Ca²⁺ and two COO^– groups on different PAA blocks can induce the chain association. Using a combination of static and dynamic laser light scattering, we studied the effect of Ca²⁺ and temperature as well as the sequence of adding Ca²⁺ ions and heating the solution on such association. We found that (1) the association is controllable and reversible, (2) a distinct hysteresis is observed between the heating and cooling processes, (3) the time evolution of the average aggregation number (<i>N</i>_agg) and the average hydrodynamic radius (⟨<i>R</i>_h⟩) of the aggregates can be expressed by a single-exponential equation, (4) the aggregates have a fractal dimension of 1.5–1.9, suggesting a diffusion-limited process, and (5) adding Ca²⁺ before heating results in the aggregates with a more open and looser structure. The current study provides a model system to investigate a more complicate problem, namely, the effect of metal ions on the stability of protein chains

Different Kinetic Pathways of Early Stage Calcium-Phosphate Cluster Aggregation Induced by Carboxylate-Containing Polymers

Acidic proteins are critical to biomineral formation, although their precise mechanistic function remains poorly understood. A number of recent studies have suggested a nonclassical mineralization model that emphasizes the importance of the formation of polymer-stabilized mineral clusters or particles; however, it has been difficult to characterize the precursors experimentally due to their transient nature. Here, we successfully captured stepwise evolution of transient CaP clusters in mineralizing solutions and studied the roles of functional polymers with laser light scattering (LLS) to determine how these polymers influence the stability of nanoclusters. We found that the polymer structure can alter CaP aggregation mechanisms, whereas the polymer concentration strongly influences the rate of CaP aggregation. Our results indicate that the ability of acidic biomolecules to control the formation of relatively stable nanoclusters in the early stages may be critical for intrafibrillar mineralization. More importantly, LLS provided information about the size and the structural evolution of CaP aggregates, which will help define the process of controlled biomineralization

Label-Free Confocal Raman Mapping of Transportan in Melanoma Cells

Cell-penetrating peptides (CPPs) are promising vectors for the intracellular delivery of a variety of membrane-impermeable bioactive compounds. The mechanisms by which CPPs cross the cell membrane, and the effects that CPPs may have on cell function, still remain to be fully clarified. In this work, we employed confocal Raman microscopy (CRM) and atomic force microscopy (AFM) to study the infiltration and physiological effects of the amphipathic CPP transportan (Tp) on the metastatic melanoma cell line SK-Mel-2. CRM enabled the detection of label-free Tp within the cells. Raman maps of live cells revealed rapid entry (within 5 min) and widespread distribution of the peptide throughout the cytoplasm and the presence of the peptide within the nucleus after ∼20 min. Principal component analysis of the CRM data collected from Tp-treated and untreated cells showed that Tp Raman bands were not positively correlated with lipid Raman bands, indicating that Tp entered the cells via a nonendocytic mechanism. Analysis of intracellularly recovered Tp by mass spectrometry showed that Tp remained intact in SK-Mel-2 cells for up to 24 h. The Raman spectroscopic data also showed that, although Tp was predominantly unstructured (random coil) in aqueous solution, it accumulated to high densities within the cells with mostly β-sheet and α-helical structures. AFM was employed to measure the effect of Tp treatment on cell stiffness. These data showed that Tp induced a significant increase in cell stiffness within the first hour of treatment, which was partially abated after 2 h. It is hypothesized that the increase in cell stiffness was the result of cytoskeletal changes triggered by Tp

Programming DNA Aptamer Arrays of Prescribed Spatial Features with Enhanced Bioavailability and Cell Growth Modulation

Epithelial cell adhesion molecules (EpCAMs) play pivotal roles in tumorigenesis in many cancer types, which is reported to reside within nano- to microscale membrane domains, forming small clusters. We propose that building multivalent ligands that spatially patch to EpCAM clusters may largely enhance their targeting capability. Herein, we assembled EpCAM aptamers into nanoscale arrays of prescribed valency and spatial arrangements by using a rectangular DNA pegboard. Our results revealed that EpCAM aptamer arrays exhibited significantly higher binding avidity to MCF-7 cells than free monovalent aptamers, which was affected by both valency and spatial arrangement of aptamers. Furthermore, EpCAM aptamer arrays showed improved tolerance against competing targets in an extracellular environment and potent bioavailability and targeting specificity in a xenograft tumor model in mice. This work may shed light on rationally designing multivalent ligand complexes of defined parameters with optimized binding avidity and targeting capability toward various applications in the biomedical fields

Comparisons of three models for different percentages of acquired k-space data.

<p>Comparisons of three models for different percentages of acquired k-space data.</p

Balanced Sparse Model for Tight Frames in Compressed Sensing Magnetic Resonance Imaging

<div><p>Compressed sensing has shown to be promising to accelerate magnetic resonance imaging. In this new technology, magnetic resonance images are usually reconstructed by enforcing its sparsity in sparse image reconstruction models, including both synthesis and analysis models. The synthesis model assumes that an image is a sparse combination of atom signals while the analysis model assumes that an image is sparse after the application of an analysis operator. Balanced model is a new sparse model that bridges analysis and synthesis models by introducing a penalty term on the distance of frame coefficients to the range of the analysis operator. In this paper, we study the performance of the balanced model in tight frame based compressed sensing magnetic resonance imaging and propose a new efficient numerical algorithm to solve the optimization problem. By tuning the balancing parameter, the new model achieves solutions of three models. It is found that the balanced model has a comparable performance with the analysis model. Besides, both of them achieve better results than the synthesis model no matter what value the balancing parameter is. Experiment shows that our proposed numerical algorithm constrained split augmented Lagrangian shrinkage algorithm for balanced model (C-SALSA-B) converges faster than previously proposed algorithms accelerated proximal algorithm (APG) and alternating directional method of multipliers for balanced model (ADMM-B).</p></div

(-)-Epigallocatechin gallate (EGCG) inhibited the formation of lipofuscin (LF) β-rich amyloidogenesis structure.

<p>LF and LF+EGCG represent LF and EGCG (300 μM) treated LF groups after 96 h of incubation, respectively.</p