Methane is one of the indicative gases in power transformer oil, and the detection of methane dissolved in oil with high accuracy is of great importance for dissolved gases analysis and fault ...diagnosis inside power transformers. Based on the Beer-Lambert spectral absorption law, dissolved methane detection with tunable diode laser absorption spectrum (TDLAS) is proposed in this paper for the advantages of high sensitivity and resolution. On the basis of wavelength modulation spectroscopy, a specialized TDLAS system was established. To meet the actual needs of field testing, the anti-vibration design of an integrated Herriott cell and a gas pressure (P)/temperature (T) setting are worked out. Photodetector, collimator, and Herriott cell are integrated into one component to reduce the effects of vibration. It is investigated that the temperature has little effect on the second harmonic amplitude in the range of 30 °C ~ 50 °C, and the vacuum pressure is reasonably set at about 1 kPa. Experimental results showed that the resolution of sensitivity could be reached as 6.8 mV/(μL/L), the maximum deviation was less than ±4 μL/L, and the response time is less than 5 min. In the end, field application was also carried out, proving it is a prospective online sensing technique to serve oil-immersed power transformers better.
We propose a high sensitivity optical fiber sensor for detecting the acoustic emission generated by the partial discharge in gas-insulated-switchgear (GIS). A model is established to investigate the ...effects of the cylinder coil on the sensitivity, the bandwidth, and the detection limit. After that, the proposed sensor was modified based on the effects. The average sensitivity of the optimized acoustic emission (AE) optical fiber sensor is 32 dB higher than that of the conventional lead zirconate titanate (PZT) in the frequency range from 20 kHz to 100 kHz. Moreover, the experimental results show that the detectable partial discharge initial voltage for the proposed optical system is 17.1% lower than that for the PZT system, and the amplitude of the signal detected by the proposed optical system is 525% higher than that detected by the PZT system.
A novel breast ultrasound tomography system based on a circular array of capacitive micromechanical ultrasound transducers (CMUT) has broad application prospects. However, the images produced by this ...system are not suitable as input for the training phase of the super-resolution (SR) reconstruction algorithm. To solve the problem, this paper proposes an improved medical image super-resolution (MeSR) method based on the sparse domain. First, we use the simultaneous algebraic reconstruction technique (SART) with high imaging accuracy to reconstruct the image into a training image in a sparse domain model. Secondly, we denoise and enhance the contrast of the SART images to obtain improved detail images before training the dictionary. Then, we use the original detail image as the guide image to further process the improved detail image. Therefore, a high-precision dictionary was obtained during the testing phase and applied to filtered back projection SR reconstruction. We compared the proposed algorithm with previously reported algorithms in the Shepp Logan model and the model based on the CMUT background. The results showed significant improvements in peak signal-to-noise ratio, entropy, and average gradient compared to previously reported algorithms. The experimental results demonstrated that the proposed MeSR method can use noisy reconstructed images as input for the training phase of the SR algorithm and produce excellent visual effects.
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•The SnS2-covalent organic framework van der Waals heterojunction (SnS2COF) was constructed.•With good photoelectric properties, SnS2COF can realize separation and transfer of ...electron-hole.•The electron flow path of heterojunction conforms to Z-scheme by experimental study and theoretical calculation.•SnS2COF can effectively reduce and remove U (VI) from rare earth tailings wastewater under UV/Vis light.
Uranium removal by photocatalytic reduction is one of the most promising methods to reduce radioactive contamination in wastewater. Herein, a Z-scheme van der Waals heterojunction photocatalyst (SnS2COF) was synthesized in situ by combining covalent organic frameworks (COF) with semiconductor (SnS2) for U (VI) reduction in rare earth tailings wastewater. The synthesis method of van der Waals heterojunction is simple and solves the problem of no hanging bond in composite components. In this heterojunction, large areas of van der Waals interaction form high-speed electron transport channels. In addition, it is deduced that SnS2COF fits the Z-scheme heterojunction electron transport mode through the theoretical calculation of the ground state and excited state electron density difference and the related band structure. Under the photoexcitation, the direction of electron flow is reversed, which further promotes the separation of the photogenerated electron (e−)-hole (h+) under the action of the built-in electric field, maintains the high reducibility of the conduction band, and avoids the photocorrosion of SnS2. Compared with inorganic-inorganic heterojunction, SnS2COF has a wider light absorption range, more active sites, and higher e−-h+ separation and transfer efficiency. Therefore, it had a higher U (VI) reduction removal capacity, up to 1123.3 mg g−1, far surpassing the SnS2 and COF counterparts under ultraviolet/visible light. And the U (VI) removal rate reached 98.5 % in rare earth tailings wastewater. The design concept of organic–inorganic heterojunction materials provides an alternative strategy for improving the photocatalytic performance.
Long noncoding RNAs (lncRNAs) are a new class of regulatory noncoding RNAs. Emerging evidences indicate that lncRNAs play a critical role in the development of hepatocellular carcinoma (HCC). ...Although several lncRNAs have been annotated, the association of most lncRNAs with HCC is unknown. In this study, we investigated lncRNA alterations in HCC by performing lncRNA microarray analysis. We identified a novel lncRNA called HCC-associated lncRNA (HCAL) that was highly expressed in HCC tissues. HCAL upregulation was clinically associated with poor differentiation, intravascular cancer embolus, and decreased survival of patients with HCC. HCAL silencing significantly inhibited the growth and metastasis of HCC cells both in vitro and in vivo. Interestingly, transcriptome-sequencing analysis of HCAL-knockdown cells showed alterations in some cancer-related pathways. Mechanistically, HCAL directly interacted with and functioned as a sponge for microRNAs such as miR-15a, miR-196a, and miR-196b to modulate LAPTM4B expression. Taken together, our findings suggest the presence of a novel lncRNA-miRNA-mRNA regulatory network, i.e., the HCAL-miR-15a/miR-196a/miR-196b-LAPTM4B network, in HCC and indicate that HCAL may be a potential target for treating HCC.
Abstract
Background
As important producers using photosynthesis on Earth, cyanobacteria contribute to the oxygenation of atmosphere and the primary production of biosphere. However, due to the ...eutrophication of urban waterbodies and global warming, uncontrollable growth of cyanobacteria usually leads to the seasonal outbreak of cyanobacterial blooms. Cyanophages, a group of viruses that specifically infect and lyse cyanobacteria, are considered as potential environment-friendly agents to control the harmful blooms. Compared to the marine counterparts, only a few freshwater cyanophages have been isolated and genome sequenced to date, largely limiting their characterizations and applications.
Results
Here, we isolated five freshwater cyanophages varying in tail morphology, termed Pam1~Pam5, all of which infect the cyanobacterium
Pseudanabaena mucicola
Chao 1806 that was isolated from the bloom-suffering Lake Chaohu in Anhui, China. The whole-genome sequencing showed that cyanophages Pam1~Pam5 all contain a dsDNA genome, varying in size from 36 to 142 Kb. Phylogenetic analyses suggested that Pam1~Pam5 possess different DNA packaging mechanisms and are evolutionarily distinct from each other. Notably, Pam1 and Pam5 have lysogeny-associated gene clusters, whereas Pam2 possesses 9 punctuated DNA segments identical to the CRISPR spacers in the host genome. Metagenomic data-based calculation of the relative abundance of Pam1~Pam5 at the Nanfei estuary towards the Lake Chaohu revealed that the short-tailed Pam1 and Pam5 account for the majority of the five cyanophages. Moreover, comparative analyses of the reference genomes of Pam1~Pam5 and previously reported cyanophages enabled us to identify three circular and seven linear contigs of virtual freshwater cyanophages from the metagenomic data of the Lake Chaohu.
Conclusions
We propose a high-throughput strategy to systematically identify cyanophages based on the currently available metagenomic data and the very limited reference genomes of experimentally isolated cyanophages. This strategy could be applied to mine the complete or partial genomes of unculturable bacteriophages and viruses. Transformation of the synthesized whole genomes of these virtual phages/viruses to proper hosts will enable the rescue of
bona fide
viral particles and eventually enrich the library of microorganisms that exist on Earth.
The temperature distribution on the gas-insulated line (GIL) spacer affects surface charge accumulation. However, the spacer temperature distribution is hard to measure because the conventional ...electric sensors are large dimensions, hard to multiplex, and sensitive to electromagnetic interference (EMI). In this article, a distributed temperature measurement system of GIL spacer based on the optical frequency domain reflectometry (OFDR) was developed to solve the problems. In this system, ultraweak fiber Bragg grating (FBG) was adopted to replace single-mode fiber due to its higher signal-to-noise ratio. The demodulation method was described for compensating the nonlinear frequency tuning errors induced by the unstable tunable laser. In addition, the relationship between the spacer temperature and the wavelength shift was determined in the calibration experiment. Moreover, the temperature distribution on a 126-kV GIL spacer was measured by the proposed OFDR system. The data processing method for 3-D surface temperature on cone-type spacer was also introduced. High-resolution temperature distribution on the spacer surface was successfully obtained using OFDR system, which is unable to accomplish with the conventional electric temperature sensor.
•Develop a comprehensive survey on receptivity toward the use of reclaimed water for cities in China.•Conduct a survey on receptivity toward the use of reclaimed water in Tianjin.•Citizen in Tianjin ...are generally receptive toward the use of reclaimed water.•Provide valuable information for reclaimed water development in Tianjin.
Tianjin is a large, rapidly growing urban center in northern China. This region has a semi-arid climate and limited water resources. Tianjin has a thriving economy and a growing population with a substantial and growing water need. Efficient use of limited water resources is critical to its continued growth. While the development of new water sources is ongoing, the reclamation of existing water can provide a substantial contribution to meeting the water needs of the region. A positive attitude by the public toward the use of reclaimed water is critical to the full development and utilization of this resource. The present study examines public knowledge, perceptions and attitudes toward water resources, with a focus on the use of reclaimed water as gaged by a survey. Survey results indicate that the general public is aware that water resources are limited, but is relatively unaware of where their water comes from, which sectors are the largest water consumers and what happens to the water after it has been used. Further, public awareness of the need to conserve water is relatively low. Reclaimed water is currently used by 54% of the population. The public is highly receptive to the use of reclaimed water, but not for domestic use and potable use. Analysis of the survey results indicates a correlation between people's social and economic background, and their attitudes toward the use of reclaimed water. People with a higher education and income level are more inclined to use reclaimed water and are more willing to pay for it. The study makes recommendations for improving the receptivity of the public toward the use of reclaimed water.
A novel hydrazone covalent organic framework (TY-Hz COF) has been constructed for simultaneous detection and recovery of Au(III) with high sensitivity and excellent selectivity. The unique ...fluorescent properties of TY-Hz COF can be exploited to selectively detect Au(III) via fluorescence quenching, and the abundant hydrazone groups on TY-Hz COF can capture Au(III) by coordination and hydrogen bonding interactions and further reduce Au(III) to Au(0) through redox, thus possessing a high recovery efficiency and a fast kinetics (within 2 min) for Au(III) from electronic waste.
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•A fluorescent hydrazone covalent organic framework (TY-Hz COF) has been constructed.•The TY-Hz COF can be exploited for selective and sensitive detection of Au(III).•The hydrazone groups of TY-Hz COF facilitate fast Au recovery from electronic waste.•TY-Hz COF can efficiently capture Au by coordination, hydrogen bonding and further redox.
Developing a material that can simultaneously detect and recover Au(III) is economically desirable. Herein, we constructed a two-dimensional mesoporous fluorescent covalent organic framework named TY-Hz COF by integrating 1,3,6,8-tetra(4-formylphenyl)pyrene (TY) and terephthalic dihydrazide (Hz) into a π-conjugated framework for simultaneous detection and recovery of Au(III). The TY-Hz COF suspension can rapidly (10 s) and sensitively response to Au(III) with electron transfer-induced fluorescence quenching and visual color change from bright yellow to dark green, and the limit of detection is as low as 17 nM. Moreover, TY-Hz COF can capture more than 92% Au(III) in the solution with extremely fast kinetics (within 2 min) and excellent selectivity with a maximum adsorption capacity of 1008.30 mg g-1. It is worth mentioning that TY-Hz is the first type of COF that achieves Au(III) detection, adsorption and chemical reduction simultaneously. Mechanistic studies reveal that the detection and adsorption behaviors can be attributed to the synergistic effect of reduction, coordination interaction between neutral amide functional groups and Au(III), and hydrogen bonding between protonated amides and AuCl4-. These results suggest that TY-Hz COF shows great potential for Au(III) detection and recovery in electronic waste (e-waste).
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