a b s t r a c tPlastics have been the most consumed materials of human societies in recent decades and, in the mean time, one of the major products obtained from landfill mining. Characteristics of the landfill mined plastic wastes and their recovery potential were the key points to determine the feasibility of landfill mining projects. We collected municipal solid waste samples of different storage years from the landfill and did mechanical screening and manual separating to sort out plastic wastes, and a typical old landfill, which is of 24 storage years and located in central China, was taken as our studied case. According to our research, plastic wastes accounted for 10.62 ± 5.12% of the total stored wastes in the old landfill, among which, 69.13% was plastic bags (white PE plastic bags accounted for 11.34%; colored PE plastic bags 29.77%; other plastic bags 28.02%), and 30.87% was other plastics (incl. PP, PVC, PS, etc.). The average moisture content in the plastic waste was 19.96 ± 4.65% and the average impurities content was 71.02 ± 6.31% before manual washing and cleaning. The VS, ash, fixed carbon and calorific value of manually cleaned plastic wastes were 87.09 ± 0.55%, 10.84 ± 1.19%, 2.07 ± 0.85% and 43.18 ± 1.49 MJ kg À1 , respectively. Elements testing (C, N, O, S, Cl, Si, Al) and surface images analysis under scanning electron microscope showed that normal cleaning techniques had a difficulty in thoroughly getting rid of all the impurities on the surface of plastic bags excavated from old landfill, which will impede plastic wastes from being mechanical recycled as renewable materials or being chemically recycled by either pyrolysis, gasification, hydrogenation. Incineration or treating as residue derived fuels (RDFs) for recovering energy was the most practical way to process landfill mining plastic wastes under the normal cleaning techniques.

Sensitive and specific detection of DNA methylation in CpG sites of genomic DNA is imperative for rapid epigenetic evaluation and early cancer diagnosis. Here, we employ for the first time the thermostable ligation for methylated DNA discrimination and hyperbranched rolling circle amplification (HRCA) for signal enhancement, without the need for restriction enzymes, PCR amplification, or fluorescence-labeled probes. After bisulfite treatment of methylated DNA, the methylation-specific linear padlock probe can be circularized only in the presence of methylated DNA and serves subsequently as a template for HRCA, whose products are easily detected using SYBR Green I and a standard fluorometer. While in the presence of unmethylated DNA, the linear padlock probe cannot be circularized because of the defectively matched substrate, and no HRCA occurs. This ligation-mediated HRCA-based method exhibits excellent specificity and high sensitivity with a detection limit of 0.8 fM and a detection range of 4 orders of magnitude, and it can even distinguish as low as 0.01% methylation level from the mixture, which is superior to most currently used methods for DNA methylation assay. This method can be further applied to analyze genomic DNA in human lung cancer cells.

Target recycling-oriented amplification has been widely applied for sensitive detection of DNA, RNA, and proteins due to its successful overcoming the inherent limitation of target-to-signal ratio of 1:1 in the traditional hybridization assay. Exonuclease III (Exo III) is usually used as the cleavage enzyme in the target recycling-oriented amplification because of its easy availability, high catalytic activity, and wide applicability. Even though Exo III is assumed to be double-stranded DNA (dsDNA) specific exonuclease in most literature, its cleavage of single-strand DNA (ssDNA) does occur, resulting in the target-independent degradation of probes. Herein, we design an intramolecular displacement probe with the capability of resistance to the nonspecific digestion of Exo III and fast hybridization kinetics. Through the substitution of 2-aminopurine for adenine in the intramolecular displacement probes, we develop a rapid and label-free approach to monitor Exo III-assisted target recycling amplification. We further demonstrate that this method can be used for the detection of DNA and proteins with excellent specificity and high sensitivity. Importantly, this method can be extended to rapid, label-free and multiplexed detection of various nucleic acids, proteins, and small molecules using different kinds of fluorescent nucleotide analogues and specific aptamers.

a b s t r a c tUrban residential buildings are formed, maintained and reformed by different external material and energy flows, and their behaviors of input, accumulation and output are characterized by their architectural factors and modes of use that usually determine the consumption of material and energy of a building at its overall life cycle.In this research, we took Beijing city, a rapid developing city as a case study, and examined material flows of urban residential building system based on a survey of typical residential buildings in the urban areas of Beijing city. The quantitative analysis were made to describe the input, transformation/accumulation, and output of building materials from the year 1949 to 2008, and a comparative analysis was done to identify the differences of material uses among the buildings with different architectural structures as masonry-concrete, and steel-concrete.During the period from 1949 to 2008, there were six main materials of cement, sand, gravel, steel, bricks and timber used in urban residential building system in Beijing. The total amount of material imported into the system was 5.1 × 10 8 t, among which the accumulated amount was 4.7 × 10 8 t, an accumulation rate of 92.5%, and the total of building wastes reached 3.9 × 10 7 t. Among the buildings with two architectural structures, the total amount of material use for buildings with steel-concrete structure was larger than masonry-concrete. It was found that the buildings with steel-concrete structure experienced a rapid increase since the year 1979 in Beijing. As a result of rapid urban development, the large-scale reformation and demolishment of urban old buildings also led to a rapid growth of the amount of building wastes. And the building wastes generated in the process of reformation and demolition began to exceed that produced in the process of new buildings construction. The amount of building wastes generated from 2004 to 2008 accounted for 52.2% of the total that generated from 1949 to 2008.From this research, the rapid development of Beijing's residential building system in the past 60 years became a big ecological pressure for urban sustainable building development. It is important to change the traditional model of urban construction, and develop some sustainable or ecologically friendly construction technologies to enhance the capacity of recycling and reuse of residential building wastes for realizing a sustainable urban building construction and management in Beijing.

a b s t r a c tLandfill mining is an environmentally-friendly technology that combines the concepts of material recycling and sustainable waste management, and it has received a great deal of worldwide attention because of its significant environmental and economic potential in material recycling, energy recovery, land reclamation and pollution prevention. This work applied a cost-benefit analysis model for assessing the economic feasibility, which is important for promoting landfill mining. The model includes eight indicators of costs and nine indicators of benefits. Four landfill mining scenarios were designed and analyzed based on field data. The economic feasibility of landfill mining was then evaluated by the indicator of net present value (NPV). According to our case study of a typical old landfill mining project in China (Yingchun landfill), rental of excavation and hauling equipment, waste processing and material transportation were the top three costs of landfill mining, accounting for 88.2% of the total cost, and the average cost per unit of stored waste was 12.7 USD ton À1 . The top three benefits of landfill mining were electricity generation by incineration, land reclamation and recycling soil-like materials. The NPV analysis of the four different scenarios indicated that the Yingchun landfill mining project could obtain a net positive benefit varying from 1.92 million USD to 16.63 million USD. However, the NPV was sensitive to the mode of land reuse, the availability of energy recovery facilities and the possibility of obtaining financial support by avoiding post-closure care.

Municipal solid waste (MSW) landfills are the most prevalent waste disposal method and constitute one of the largest sources of anthropogenic methane emissions in the world. Microbial activities in disposed waste play a crucial role in greenhouse gas emissions; however, only a few studies have examined metagenomic microbial profiles in landfills. Here, the MiSeq high-throughput sequencing method was applied for the first time to examine microbial diversity of the cover soil and stored waste located at different depths (0-150cm) in a typical MSW landfill in Yangzhou City, East China. The abundance of microorganisms in the cover soil (0-30cm) was the lowest among all samples, whereas that in stored waste decreased from the top to the middle layer (30-90cm) and then increased from the middle to the bottom layer (90-150cm). In total, 14 phyla and 18 genera were found in the landfill. A microbial diversity analysis showed that Firmicutes, Proteobacteria, and Bacteroidetes were the dominant phyla, whereas Halanaerobium, Methylohalobius, Syntrophomonas, Fastidiosipila, and Spirochaeta were the dominant genera. Methylohalobius (methanotrophs) was more abundant in the cover layers of soil than in stored waste, whereas Syntrophomonas and Fastidiosipila, which affect methane production, were more abundant in the middle to bottom layers (90-150cm) in stored waste. A canonical correlation analysis showed that microbial diversity in the landfill was most strongly correlated with the conductivity, organic matter, and moisture content of the stored waste.

The pinewood nematode, Bursaphelenchus xylophilus, has caused significant damage to pine plantations both in East Asia and North America and is an important quarantine organism. A real-time polymerase chain reaction (PCR) assay was developed to detect B. xylophilus. A set of primers and probe specific for B. xylophilus was designed to target the ribosomal DNA internal transcribed spacer region. Optimal primer concentration, Mg(2+) concentration, and extension temperature were 400 nM, 3.0 mM, and 60 degrees C, respectively. The assay was highly specific and sensitive, detecting as little as 0.01 ng of B. xylophilus DNA. The real-time PCR assay also successfully detected B. xylophilus in field samples, and it should be very useful for quarantine purposes.

Highly sensitive detection of transcription factors is essential to the evaluation of cellular development and the disease state. However, so far most detection methods are usually laborious and time-consuming with a poor sensitivity. Here, we demonstrate a simple and ultrasensitive approach for transcription factor detection based on the target-converted helicase-dependent amplification assay. We employ a hairpin probe bearing the transcription factor binding site to convert the protein signal to the DNA signal, which can be further amplified by helicase-dependent amplification. With the digestion of excess probes by the exonucleases and the subsequent one primer-triggered high fidelity amplification, zero-background signal can be achieved in the absence of a transcription factor. This method exhibits excellent specificity and high sensitivity with the detection limit of 9.3× 10(-13) M and the detection range over 4 orders of magnitude, which is superior to most currently used approaches for transcription factor detection. Moreover, the proposed method has significant advantages of simple, rapid, and low cost without the need of any labeled DNA probes and might be extended to selectively detect various DNA-binding proteins by simply changing the binding-site sequences of hairpin probes.