285 research outputs found
The feasibility and microbial community dynamics of using down flow hanging sponges (DHS) reactor in treating high strength soft drink wastewater
Get PDFThe feasibility of using a standalone down-flow hanging sponge (DHS) reactor to treat high organic strength soft drink wastewater was investigated by operation over 700 days. At the same time, the microbial compositions were characterized and related to reactor performance. Synthetic wastewater at a concentration of 3000 mg/L chemical oxygen demand (COD) was directly fed to two identical DHS reactors operated in parallel. The effluent from these two reactors was then combined and fed to a third DHS reactor identical as the first two in physical scale. The first two DHS reactors were operated with a hydraulic retention time (HRT) of 15.3 hours and an organic loading rate of 4.9 kg COD/m3 sponge volume/day, and achieved > 90% organic matters removal efficiency. The third reactor consistently achieved a final effluent COD 60% of organic and nitrogen species contents were removed at the upper part of the reactor.
The microbial community analyses together with redundancy analysis revealed that the community structures could be distinguished based on the locations of individual sponges taken along the reactor. Also, microbial community structures were continuously shifted during the entire operation period and a feeding accident influenced the community structures significantly. In general, at the end of the operation period, OTUs in phylum Proteobacteria were more abundant in the reactor with good organic removal efficiency (>90%) than that with poor efficiency (<50%). In contract, OTUs related to Bacteroidetes was observed to be more abundant in the reactor with poor organic removal efficiency. OTUs closely related to Tolumonas auensis, and Rivicola pingtungensis had higher abundance in the upper part communities than middle and lower part of the reactor with good organic removal efficiency and these OTUs were likely targeting the major components in the feeding substrate. In addition, the lower abundance of these OTUs in the upper part of the reactor with poor organic removal efficiency than that with good efficiency might also indicate the importance of these OTUs in treating the soft drink wastewater tested in this study.Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2018-08-01The student, Junhui Liao, accepted the attached license on 2016-06-22 at 15:30.The student, Junhui Liao, submitted this Thesis for approval on 2016-06-22 at 15:31.This Thesis was approved for publication on 2016-06-23 at 11:12.DSpace SAF Submission Ingestion Package generated from Vireo submission #9692 on 2016-11-10 at 12:19:31Made available in DSpace on 2016-11-10T18:27:30Z (GMT). No. of bitstreams: 2
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Research and application of L-shaped ground well gas drainage technology in mining area
No full textBy law mining fracture morphology analysis, based on coal face gas flow characteristics, obtain the L-shaped surface well layout area in the mining area under the influence of mining. Analysis of overlying strata "three zones" distribution, the calculation method of the height of overburden rock "three zones" designed in mining area ground well structure proposed safety drainage system construction plan. In Sihe Mine was L-shaped ground mining area well engineering practice, the average gas production at a concentration of 80%, with an average drainage net amount 22 000 m3 / d, a total of more than 300 days running, drainaging 6.5 million CBM m3. After the implementation of drainage work surface corner gas content fell 46.5%, to effectively improve production efficiency, for the surface treatment gas play a key role. Successfully removed Mining Face Gas for safe production constraints, to protect the mining of coal mine safety, and achieved good social and economic results, with good promotional value
Yi fen zi dong li mo ni yan jiu cha er tong yi gou mei de xuan ze xing
No full textTung, Chun Fai = 以分子動力模擬研究查耳酮異構酶的選擇性 / 董俊暉.Thesis M.Phil. Chinese University of Hong Kong 2015.Includes bibliographical references (leaves 57-59).Abstracts also in Chinese.Title from PDF title page (viewed on 29, September, 2016).Tung, Chun Fai = Yi fen zi dong li mo ni yan jiu cha er tong yi gou mei de xuan ze xing / Dong Junhui
5-Fluorouracil Treatment Alters the Efficiency of Translational Recoding
No full text5-fluorouracil (5-FU) is a chemotherapeutic agent that has been extensively studied since its initial development in the 1950s. It has been suggested that the mechanism of action of 5-FU involves both DNA- and RNA-directed processes, but this has remained controversial. In this study, using a series of in vivo reporter constructs capable of measuring translational recoding, we demonstrate that cells exposed to 5-FU display a reduced capacity to engage in a variety of translational recoding events, including +1 programmed frameshifting (PRF) and −1 PRF. In addition, 5-FU-treated cells are much less accurate at stop codon recognition, resulting in a significant increase in stop codon-readthrough. Remarkably, while the efficiency of cap-dependent translation appears to be unaffected by 5-FU, 5-FU-treated cells display a decreased ability to initiate cap-independent translation. We further show that knockdown of thymidylate synthase, an enzyme believed to be at the center of 5-FU-induced DNA damage, has no effect on the observed alterations in translational recoding. On the other hand, ribosomal RNA (rRNA) pseudouridylation, which plays an important role in translational recoding, is significantly inhibited. Taken together, our results suggest that the observed effect of 5-FU on recoding is an RNA-directed effect. Our results are the first to show definitely and quantitatively that translational recoding is affected by exposure to 5-FU. Thus, it is possible that a substantial portion of 5-FU cytotoxicity might possibly be the result of alterations in translational recoding efficiency
Ablation of Proliferating Marrow with 5‐Fluorouracil Allows Partial Purification of Mesenchymal Stem Cells
Get PDFThe ability to identify and maintain mesenchymal stem cells in vitro is a prerequisite for the ex vivo expansion of cells capable of effecting mesenchymal tissue regeneration. The aim of this investigation was to develop an assay to enrich and ultimately purify mesenchymal stem cells. To enrich the population of mesenchymal stem cell‐like cells, rats or mice were administered 5‐fluorouracil (5‐FU) in vivo. Limiting dilution analysis demonstrated that 5‐FU‐treated bone marrow had the potential to form colony‐forming units‐fibroblastic (CFU‐F) at a 10‐fold or sixfold enrichment compared to normal bone marrow in rats or mice, respectively. In vivo and in vitro differentiation assays supported the enrichment and purification effects. In vitro, bone marrow cultures from 5‐FU‐treated bone marrow demonstrated lineage‐specific gene expression in lineage‐specific medium conditions in contrast to the multilineage gene expression of control bone marrow cultures. In vivo implantation of 5‐FU‐treated cells that were not expanded in culture generated ossicles containing an intact bone cortex and mature hematopoietic components, whereas non‐5‐FU‐treated bone marrow only formed fibrous tissues. Our results demonstrate that enrichment of a quiescent cell population in the bone marrow by in vivo treatment of 5‐FU spares those undifferentiated mesenchymal stem cells and influences the differentiation of bone marrow stromal cells in vitro and in vivo. This prospective identification of a population of mesenchymal cells from the marrow that maintain their multilineage potential should lead to more focused studies on the characterization of a true mesenchymal stem cell.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90309/1/241573_ftp.pd
Effect of heating rate on thermal cracking characteristics and kinetics of Xinjiang oil sand bitumen by TG–FTIR
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The Antecedents of Employee Engagement: a Comparative Analysis between Finland and Asia
Get PDFEarlier research on employee engagement has discovered quite a few factors that might impact the levels of employee engagement. However, these academic studies have lacked a structured framework to have a holistic look at the antecedents of employee engagement. To bridge this gap, this research transforms the Aon Hewitt Employee Engagement (AHEE) model, a useful model in the practical world, into an academically rigorous framework. In practice, the author adopted a mixed methodology of both focus group interviews and questionnaires. Specifically, six focus group interviews in three countries were conducted and 93 survey responses in three countries were collected. Based on the findings, the author further refined the AHEE model into a more robust model of eight engagement predictors in five dimensions, including financial compensation, work-life balance, team member exchange, perceived managerial support, job security, respect, learning and development, and performance evaluation.
Furthermore, this study answers the call in employee engagement research to explore the research question: how might engagement predictors have different influences in different cultural settings? To address this, comparative analyses of engagement predictors between Finland and Asia were performed in this study. The results show that the impacts of respect, perceived managerial support, learning and development and work-life balance on employee engagement are different in Asia compared to Finland. To be more specific, respect and perceived managerial support have a more positive influence on employee engagement in Finland than in Asia. Interestingly, both learning and development and work-life balance have a negative relationship with employee engagement in Finland while the relationship is positive in Asia
Mechanical Performance of Bio-Inspired Gyroid and Primitive Concrete Structures under Combined Compression and Torsion Loads:A Discrete Element Method Study
Get PDFBioinspired lightweight Primitive and Gyroid structures are two well-known TPMS (triply periodic minimal surface) cellular structures. These structures have been shown to possess high specific strength and energy absorption capacity, and thus hold great promise for a range of prefabricated civil engineering applications. As a result, concrete cellular TPMS structures have garnered the attention of researchers. However, prior to this study, no investigation has been carried out on the mechanical properties and failure patterns of concrete Primitive and Gyroid structures under coupled compressive and torsional loads. This lack of knowledge on the behaviour of these structures can lead to safety concerns in construction projects. To better understand the mechanical behaviour of Primitive and Gyroid structures under combined compression and torsion, the discrete element method (DEM) is adopted to simulate the TPMS structures. Both linear contact and nonlinear softbond contact models are utilized to simulate the brittle mechanical behaviour of concrete material. After validating the DEM parameters using published experimental data, the DEM models are subjected to coupled compressive and torsional loads to study their compressive and torsional bearing capacity and cracking patterns. The results indicate that the Primitive based structures outperform the Gyroid based structures in terms of both compressive and torsional resistance. The study finds that a compressive load enhances the ultimate torsional bearing capacity of TPMS structures, but a torsional load reduces their compressive bearing capacity. Additionally, the loading conditions have little impact on the cracking patterns of the four TPMS structures
A Visualized Assay for Quercetin Based on the Formation of Silver-Gold Alloy Nanoparticles
No full textA visualized assay for quercetin (QU) was first developed based on the formation of silver-gold alloy nanoparticles in this contribution. With the ability to reduce metal ions to metal substances, QU could reduce Ag+ absorbed on the surface of gold nanoparticles to metallic silver. The thickness of the formed Ag shell and the color change of the solution were proportional to the concentration of QU. Therefore, visualized detection of QU could be realized by studying the surface resonance plasmon absorption spectra of the analytical systems after addition of different concentration of QU. Under optimum conditions, trace amount of QU could be detected in the linear range 9.0x10(-7)-1.0x10(-4) mol L-1 with a detection limit of 6.5x10(-7) mol L-1. The present assay was applied in the determination of QU in human serum and satisfactory results were obtained. This assay is simple, rapid, and cost-effective, and it is a powerful complement for the spectroscopy assays for QU. Also, it is the first visualized spectroscopic assay of QU until now.Chemistry, PhysicalNanoscience & NanotechnologyMaterials Science, MultidisciplinarySCI(E)0ARTICLE2201-207
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