Application of Metal Oxide Heterostructures in Arsenic Removal from Contaminated Water

<p> It has become one of the major environmental problems for people worldwide to be exposed to high arsenic concentrations through contaminated drinking water, and even the long-term intake of small doses of arsenic has a carcinogenic effect. As an efficient and economic approach for the purification of arsenic-containing water, the adsorbents in adsorption processes have been widely studied. Among a variety of adsorbents reported, the metal oxide heterostructures with high surface area and specific affinity for arsenic adsorption from aqueous systems have demonstrated a promising performance in practical applications. This review paper aims to summarize briefly the metal oxide heterostructures in arsenic removal from contaminated water, so as to provide efficient, economic, and robust solutions for water purification.</p

Genome-wide identification of resistance genes and response mechanism analysis of key gene knockout strain to catechol in Saccharomyces cerevisiae

Engineering Saccharomyces cerevisiae for biodegradation and transformation of industrial toxic substances such as catechol (CA) has received widespread attention, but the low tolerance of S. cerevisiae to CA has limited its development. The exploration and modification of genes or pathways related to CA tolerance in S. cerevisiae is an effective way to further improve the utilization efficiency of CA. This study identified 36 genes associated with CA tolerance in S. cerevisiae through genome-wide identification and bioinformatics analysis and the ERG6 knockout strain (ERG6Δ) is the most sensitive to CA. Based on the omics analysis of ERG6Δ under CA stress, it was found that ERG6 knockout affects pathways such as intrinsic component of membrane and pentose phosphate pathway. In addition, the study revealed that 29 genes related to the cell wall-membrane system were up-regulated by more than twice, NADPH and NADP+ were increased by 2.48 and 4.41 times respectively, and spermidine and spermine were increased by 2.85 and 2.14 times, respectively, in ERG6Δ. Overall, the response of cell wall-membrane system, the accumulation of spermidine and NADPH, as well as the increased levels of metabolites in pentose phosphate pathway are important findings in improving the CA resistance. This study provides a theoretical basis for improving the tolerance of strains to CA and reducing the damage caused by CA to the ecological environment and human health

Artemis: A practical low-latency naming and routing system

Today, Internet service deployment is typically implemented with server replication at multiple locations for the purpose of load balancing, failure tolerance, and user experience optimization. Domain name system (DNS) is responsible for translating human-readable domain names into network-routable IP addresses. When multiple replicas exist, upon the arrival of a query, DNS selects one replica and responds with its IP address. Thus, the delay caused by the process of DNS query including the selection of replica is part of the connection setup latency. In this paper, we proposed Artemis, a practical low-latency naming and routing system that aims at reducing the connection setup latency by eliminating the DNS query latency while keeping the ability to perform optimal server (replica) selection based on user-defined rules. Artemis achieves these goals by integrating name resolution into the transport layer handshake. Artemis allows clients to calculate locally the IP address of a Service Dispatcher, which serves as a proxy of hosting servers. Service Dispatchers forward the handshake request from a client to a server, and the response is embedded with the server's IP address back to the client. This enables clients to connect directly with servers afterward without querying DNS servers, and therefore eliminates the DNS query latency. Meanwhile, Artemis supports user-defined replica selection policies. We have implemented Artemis and evaluated its performance using the PlanetLab testbed and RIPE Atlas probes. Our results show that Artemis reduces the connection setup latency by 26.2% on average compared with the state-of-the-art.Peer reviewe

GPR Energy Attribute Slices Based on Multivariate Variational Mode Decomposition and Teager&ndash;Kaiser Energy Operator

The GPR signals appear nonlinear and nonstationary during propagation. To evaluate the nonstationarity, the empirical mode decomposition (EMD) and its modifications have been proposed to localize the variations of energy and frequency components over time. Among the EMD&minus;based algorithms, the variational mode decomposition (VMD) is one of the representative methods. It eliminates the drawbacks of EMD, to some extent, but is still executed in one dimension. In this work, the multivariate variational mode decomposition (MVMD) algorithm is introduced for decomposing the GPR B-scans into several IMF-slices in two dimensions, which inherits the advantages of the VMD and considers the stratigraphic constraints. Then, by applying the Teager&ndash;Kaiser energy operator (TKEO) within each IMF-slice, a novel energy attribute is formed and termed as the &ldquo;TKEO-slices&rdquo;. The proposed TKEO-slices can localize the energy attribute of geophysical information of different scales with good stratigraphic continuity. The proposed scheme is evaluated by the synthetic benchmark, model data, and field data. Compared with the VMD&minus;based scheme and the classic instantaneous amplitude, the proposed TKEO-slices show better resolution and lateral continuity

Study on variation law and mechanism of coal potential signal with different lithology

The potential signal generated in the process of coal rock deformation and failure can better characterize the damage evolution process of coal rock, and has a good application prospect in the field of coal rock dynamic disaster monitoring and early warning. At present, most of the researches focus on the potential characteristics and laws of the same type of coal rock failure, and there is a lack of systematic research on the comparative analysis of potential characteristics of different types of coal rocks. At the same time, there are few comparative studies on the effect of different lithology coal rock structure failure process and components on the surface potential signal generation mechanism at the micro level. In order to deeply study the response law and difference of potential signal of coal and rock with different lithology, four kinds of samples, graphite, raw coal, sandstone and granite, are selected for uniaxial loading and the potential signals generated in the process of damage and failure are collected synchronously. The variation characteristics of potential signals of four samples under loading and failure are analyzed. The results show that the potential signal value of graphite sample is relatively low, and the potential signal fluctuates greatly during the crack damage and unstable crack propagation stages. The fluctuation of the potential signal of the raw coal sample is consistent with the fluctuation of the load, and the variation of the overall potential signal is relatively stable. The potential signal value of the sandstone sample increases rapidly in the compaction stage and the elastic deformation stage. The potential signal of the granite sample fluctuates greatly in the crack damage and unstable crack propagation stages, and the potential signal value increases faster. By scanning electron microscope and X-ray fluorescence spectrometer, the generation mechanism of potential signals of coal samples with different lithology is explained from the aspects of microstructure and components. The results show that there are more mylonic scratches from the microscopic point of view in the graphite and raw coal samples in the compaction and elastic deformation stages of coal rock loading, which indicates that the friction effect is the important reason for the electrification of the graphite and raw coal samples. The sandstone and granite samples contain more O and Si elements, and the piezoelectric effect is the key reason for the electrification of the sandstone and granite samples, and the potential signal of the sandstone sample is more affected by the piezoelectric effect. In the crack initiation and stable crack growth stage, crack damage and unstable crack propagation and unloading stage, the potential signal generation of each coal sample is mainly caused by the crack propagation and friction effect inside the sample. Among them, crack propagation is an important reason for the generation of coal-rock potential signals. The charge separation at the crack tip mainly includes three aspects, including electron escape caused by stress concentration at the crack tip, crack surface charge separation caused by crack propagation and crack tip discharge

GPR Energy Attribute Slices Based on Multivariate Variational Mode Decomposition and Teager–Kaiser Energy Operator

The GPR signals appear nonlinear and nonstationary during propagation. To evaluate the nonstationarity, the empirical mode decomposition (EMD) and its modifications have been proposed to localize the variations of energy and frequency components over time. Among the EMD−based algorithms, the variational mode decomposition (VMD) is one of the representative methods. It eliminates the drawbacks of EMD, to some extent, but is still executed in one dimension. In this work, the multivariate variational mode decomposition (MVMD) algorithm is introduced for decomposing the GPR B-scans into several IMF-slices in two dimensions, which inherits the advantages of the VMD and considers the stratigraphic constraints. Then, by applying the Teager–Kaiser energy operator (TKEO) within each IMF-slice, a novel energy attribute is formed and termed as the “TKEO-slices”. The proposed TKEO-slices can localize the energy attribute of geophysical information of different scales with good stratigraphic continuity. The proposed scheme is evaluated by the synthetic benchmark, model data, and field data. Compared with the VMD−based scheme and the classic instantaneous amplitude, the proposed TKEO-slices show better resolution and lateral continuity

Photosynthetic Product Allocations to the Organs of Pinus massoniana Are Not Affected by Differences in Synthesis or Temporal Variations in Translocation Rates

Photosynthesis and the allocation of photosynthetic products are the two main factors that determine plant growth. To understand the growth and productivity of Pinus massoniana Lamb., the diurnal changes in photosynthetic rate were continuously monitored. Furthermore, the translocation and allocation of the photosynthetic products synthesized in the morning and afternoon were explored using 13C pulse labeling. The results showed that: (1) on sunny days, the diurnal variation of the net photosynthetic rate showed a “double peak” curve, with an obvious “a depression” when temperatures were highest and humidity lowest. On cloudy days, it showed an irregular “jagged” curve, which was curve consistent with the variations in photosynthetically active radiation (PAR). Meanwhile, the photosynthetic rate changed with the transient changes in environmental factors such as PAR, temperature, and humidity. (2) The mean value of the net photosynthetic rate in the morning was higher than in the afternoon, and the response of the net photosynthetic rate to environmental change (PAR, temperature, humidity, and CO2 concentration) in the morning was greater than that in the afternoon. (3) The translocation of photosynthetic products synthesized in the afternoon was faster than that in the morning. Shortly after synthesis of photosynthetic products, the translocation of products synthesized in the morning tended toward upper organs (including current-year leaves and 1-year leaves), while the translocation of products synthesized in the afternoon decreased in the upper organs. However, after 15 days of 13C pulse labeling, the allocation of the photosynthetic products synthesized in the morning and afternoon tended to be the same. These results indicate that the differences in the photosynthetic products synthesized and the temporal differences in the translocation rates did not affect the final allocation of the photosynthetic products in the various organs of the P. massoniana. These results improve our knowledge of the functional phases of P. massoniana during the diurnal cycle