Performance and Microbial Community of Different Biofilm Membrane Bioreactors Treating Antibiotic-Containing Synthetic Mariculture Wastewater

The performance of pollutant removals, tetracycline (TC) and norfloxacin (NOR) removals, membrane fouling mitigation and the microbial community of three Anoxic/Oxic membrane bioreactors (AO-MBRs), including a moving bed biofilm MBR (MBRa), a fixed biofilm MBR (MBRb) and an AO-MBR (MBRc) for control, were compared in treating antibiotic-containing synthetic mariculture wastewater. The results showed that MBRb had the best effect on antibiotic removal and membrane fouling mitigation compared to the other two bioreactors. The maximum removal rate of TC reached 91.65% and the maximum removal rate of NOR reached 45.46% in MBRb. The addition of antibiotics had little effect on the removal of chemical oxygen demand (COD) and ammonia nitrogen (NH4+-N)—both maintained more than 90% removal rate during the entire operation. High-throughput sequencing demonstrated that TC and NOR resulted in a significant decrease in the microbial diversity and the microbial richness MBRs. Flavobacteriia, Firmicutes and Azoarcus, regarded as drug-resistant bacteria, might play a crucial part in the removal of antibiotics. In addition, the dynamics of microbial community had a great change, which included the accumulation of resistant microorganisms and the gradual reduction or disappearance of other microorganisms under antibiotic pressure. The research provides an insight into the antibiotic-containing mariculture wastewater treatment and has certain reference value

Evolutionary and Expression Analyses Show Co-option of khdrbs Genes for Origin of Vertebrate Brain

Genes generated by whole genome duplications (WGD) can be co-opted by changing their regulation process or altering their coding proteins, which has been shown contributable to the emergence of vertebrate morphological novelties such as vertebrate cartilage. Mouse khdrbs genes, differing from its invertebrate orthologs, were mainly expressed in brain, hinting that khdrbs gene family as a member of genetic toolkit may be linked to vertebrate brain development. However, the evolutionary relationship between khdrbs gene family and vertebrate brain development is unclear. First, we analyzed the evolutionary history of khdrbs gene family in metazoans, and then investigated their expression patterns during early development and in adulthood of zebrafish. We found that the duplication of khdrbs gene family by WGD took place in zebrafish, and all zebrafish khdrbs genes were predominantly expressed in the substructures of brain during early development. Given the expression of invertebrate khdrbs gene in germ line, the distinct expression domains of zebrafish khdrbs genes in brain suggested that the duplicated khdrbs genes are co-opted for promoting the evolutionary origin of vertebrate brain

Vibration Images-Driven Fault Diagnosis Based on CNN and Transfer Learning of Rolling Bearing under Strong Noise

Deep learning-based fault diagnosis of rolling bearings is a hot research topic, and a rapid and accurate diagnosis is important. In this paper, aiming at the vibration image samples of rolling bearing affected by strong noise, the convolutional neural network- (CNN-) and transfer learning- (TL-) based fault diagnosis method is proposed. Firstly, four kinds of vibration image generation method with different characteristics are put forward, and the corresponding pure vibration image samples are obtained according to the original data. Secondly, using CNN as the adaptive feature extraction and recognition model, the influences of main sensitive parameters of CNN on the network recognition effect are studied, such as learning rate, optimizer, and L1 regularization, and the best model is determined. In order to obtain the pretraining parameters, the training and fault classification test for different image samples are carried out, respectively. Thirdly, the Gaussian white noise with different levels is added to the original signals, and four kinds of noised vibration image samples are obtained. The previous pretrained model parameters are shared for the TL. Each kind of sample research compares the impact of thirteen data sharing schemes on the TL accuracy and efficiency, and finally, the test accuracy and time index are introduced to evaluate the model. The results show that, among the four kinds of image generation method, the classification performance of data obtained by empirical mode decomposition-pseudo-Wigner–Ville distribution (EP) is the best; when the signal to noise ratio (SNR) is 10 dB, the model test accuracy obtained by TL is 96.67% and the training time is 170.46 s

International Students' Socializing : Implications and Potential Solutions

Color poster with text, charts, images, and table.Socializing is a behaviour of human nature essential to a healthy mental state, which involves sociable acts such as hanging out, partying and studying together. It is a significant practice for all students in college because it helps build good relationships, reduces stress, improves grades and develops self-confidence. As international students at University of Wisconsin-Eau Claire, we do not interact with native students as much as we would like to. For that reason, our group aims to examine the way international students feel about their socializing skills at UWEC, as well as providing them with possible solutions for help if needed.University of Wisconsin--Eau Claire Office of Research and Sponsored Programs

An ultra-lightweight CFRP beam-string structure

In this work, an ultra‐lightweight beam string structure made of carbon fiber reinforced polymer (CFRP) composites was designed, optimized, fabricated and tested. ANSYS APDL was adopted to optimize the design of the structure. A four‐point bending test was carried out to investigate the structural behavior. Despite of being a non‐full‐scale structure, an exceptionally high structural efficiency, 56 N/g, was successfully achieved. Additionally, finite element analysis was conducted to investigate the effect of prestressing force in tension string. The added prestressing was identified to be able to increase the flexural strength of the structure by up to 15%. Moreover, with the thickened tension string, for instance for the 2.0‐mm‐thick string, 3% prestressing was able to provide a significant increase of the flexural strength and stiffness by up to 28% and 115%, respectively. The increased flexural strength was attributed to the improved stress distribution of compression beam. The proposed CFRP beam string structure, having an ultra‐lightweight and a high load‐carrying capacity, has a great potential to be widely adopted in conceptual developments and practical applications, particularly when high structural efficiency is required

Direct Synthesis of Lactide from Lactic Acid by Sn-beta Zeolite: Crucial Role of the Open Sn Site

Sn-beta zeolite is a promising catalyst for the direct synthesis of lactide from lactic acid; here, we clarify the relationship between its local structure and activity through the interplay of experiments and DFT calculations. The open sites (HO-Sn-(OSi)3 with adjacent Si–OH) play a key role in the high activity of Sn-beta zeolite, where the reaction rate significantly decreases from 0.2258 mmol min–1 gcat–1 to 0.0724 mmol min–1 gcat–1 if the open sites were masked with Na+. Density functional theory (DFT) calculations show that the decrease in reaction rate comes from the weaker interaction between substrate and the open Sn site by Na+ exchange, which leads to the significant increase in the Gibbs energy barrier from 34.0 kcal/mol to 57.2 kcal/mol (rate-determining step). Other activities of heteroatom M-beta zeolites (where M = Ti, Zr, Hf) were also investigated, where the open sites were found to be crucial for the high activity in the direct synthesis of lactide as well. The information provided by this work is valuable for precise design of efficient catalysts for the one-step synthesis of lactide

A Novel PEEK Foam with Ultra‐High Temperature‐Resistant by Temperature Induced Phase Separation

Abstract Polyaryletherketone is a kind of special engineering plastics with excellent comprehensive properties, high strength, good stability, and almost insoluble in any common solvent except concentrated sulfuric acid at room temperature. However, its high processing temperature also hinders its application and development in the foam. Here, a series of polyetheretherketone (PEEK) and diphenyl polyetheretherketone (PEDEK) composite foams are prepared by temperature induced phase separation, using diphenyl sulfone as solvent. The microstructure, thermal and mechanical properties of PEEK and PEDEK foam are compared. Highly porous PEEK and PEDEK foams with densities ranging from 0.13 to 0.25 g cm−3, with compressive strength ranging from 0.68 to 2.6 MPa, respectively, are produced. Meanwhile, the introduction of diphenyl structure can effectively improve the performance of PEEK foams at high temperature. It is found that PEDEK foam has a higher operating temperature than PEEK, and the compressive strength of 0.24 g cm−3 foam is still ≈1 MPa at 200 °C

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<p>Genes generated by whole genome duplications (WGD) can be co-opted by changing their regulation process or altering their coding proteins, which has been shown contributable to the emergence of vertebrate morphological novelties such as vertebrate cartilage. Mouse khdrbs genes, differing from its invertebrate orthologs, were mainly expressed in brain, hinting that khdrbs gene family as a member of genetic toolkit may be linked to vertebrate brain development. However, the evolutionary relationship between khdrbs gene family and vertebrate brain development is unclear. First, we analyzed the evolutionary history of khdrbs gene family in metazoans, and then investigated their expression patterns during early development and in adulthood of zebrafish. We found that the duplication of khdrbs gene family by WGD took place in zebrafish, and all zebrafish khdrbs genes were predominantly expressed in the substructures of brain during early development. Given the expression of invertebrate khdrbs gene in germ line, the distinct expression domains of zebrafish khdrbs genes in brain suggested that the duplicated khdrbs genes are co-opted for promoting the evolutionary origin of vertebrate brain.</p