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  • 1
    Publication Date: 2014-04-10
    Description: Aiming at the need of coiled tubing sand washing operation for the low-pressure and leaking gas pool in Qinghai gas reservoir, we developed a kind of low density nitrogen micro bubble workover fluid technology, which is composed of a new type of composite foaming agent, temporary plugging agent, composite stabilizing foam agent and the nitrogen. Observing by a microscope, we can find that the micro bubble structure is composed of a core of gas, two membranes, three layers, which has high stability (higher stability than ordinary foam stability). The performance evaluation results show that, the temperature resistance of nitrogen micro bubble workover fluid is up to 120 ℃. Compression resistance can reach 20 Mpa. API filter loss is only 11.3 ml. The high temperature and high pressure filtration is only 16.6 ml. Anti-salt can reach 10%. Anti-calcium can reach 3% and the resistance to oil pollution is more than 15%. The recovery rate of core permeability is up to 89%. The system can not only reduce the fluid column pressure and reduce the pressure difference, but the formation of micro bubble in the leakage areas on the surface of formation is widespread, and has a certain strength and toughness, and also has a certain deformability matching leakage channel of formation, which can achieve the purpose of anti-leaking. This technology was applied in Qinghai gas field for 2 wells, with an efficiency of 100%. The sand washing operation was successfully completed, with no leakage. Key words : Low density nitrogen micro bubble workover fluid; Micro bubble; Qinghai gas field
    Print ISSN: 1925-542X
    Electronic ISSN: 1925-5438
    Topics: Geosciences
    Published by CSCanada
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  • 2
    Publication Date: 2014-05-13
    Description: Aiming at the need of coiled tubing sand washing operation for the low-pressure and leaking gas pool in Qinghai gas reservoir, we developed a kind of low density nitrogen micro bubble workover fluid technology, which is composed of a new type of composite foaming agent, temporary plugging agent, composite stabilizing foam agent and the nitrogen. Observing by a microscope, we can find that the micro bubble structure is composed of a core of gas, two membranes, three layers, which has high stability (higher stability than ordinary foam stability). The performance evaluation results show that, the temperature resistance of nitrogen micro bubble workover fluid is up to 120 ℃. Compression resistance can reach 20 Mpa. API filter loss is only 11.3 ml. The high temperature and high pressure filtration is only 16.6 ml. Anti-salt can reach 10%. Anti-calcium can reach 3% and the resistance to oil pollution is more than 15%. The recovery rate of core permeability is up to 89%. The system can not only reduce the fluid column pressure and reduce the pressure difference, but the formation of micro bubble in the leakage areas on the surface of formation is widespread, and has a certain strength and toughness, and also has a certain deformability matching leakage channel of formation, which can achieve the purpose of anti-leaking. This technology was applied in Qinghai gas field for 2 wells, with an efficiency of 100%. The sand washing operation was successfully completed, with no leakage. Key words : Low density nitrogen micro bubble workover fluid; Micro bubble; Qinghai gas field
    Print ISSN: 1925-542X
    Electronic ISSN: 1925-5438
    Topics: Geosciences
    Published by CSCanada
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  • 3
    Publication Date: 2019-02-25
    Description: Background The elderly population is at risk of osteoarthritis (OA), a common, multifactorial, degenerative joint disease. Environmental, genetic, and epigenetic (such as DNA hydroxymethylation) factors may be involved in the etiology, development, and pathogenesis of OA. Here, comprehensive bioinformatic analyses were used to identify aberrantly hydroxymethylated differentially expressed genes and pathways in osteoarthritis to determine the underlying molecular mechanisms of osteoarthritis and susceptibility-related genes for osteoarthritis inheritance. Methods Gene expression microarray data, mRNA expression profile data, and a whole genome 5hmC dataset were obtained from the Gene Expression Omnibus repository. Differentially expressed genes with abnormal hydroxymethylation were identified by MATCH function. Gene ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses of the genes differentially expressed in OA were performed using Metascape and the KOBAS online tool, respectively. The protein–protein interaction network was built using STRING and visualized in Cytoscape, and the modular analysis of the network was performed using the Molecular Complex Detection app. Results In total, 104 hyperhydroxymethylated highly expressed genes and 14 hypohydroxymethylated genes with low expression were identified. Gene ontology analyses indicated that the biological functions of hyperhydroxymethylated highly expressed genes included skeletal system development, ossification, and bone development; KEGG pathway analysis showed enrichment in protein digestion and absorption, extracellular matrix–receptor interaction, and focal adhesion. The top 10 hub genes in the protein–protein interaction network were COL1A1, COL1A2, COL2A1, COL3A1, COL5A1, COL5A2, COL6A1, COL8A1, COL11A1, and COL24A1. All the aforementioned results are consistent with changes observed in OA. Conclusion After comprehensive bioinformatics analysis, we found aberrantly hydroxymethylated differentially expressed genes and pathways in OA. The top 10 hub genes may be useful hydroxymethylation analysis biomarkers to provide more accurate OA diagnoses and target genes for treatment of OA.
    Electronic ISSN: 2167-8359
    Topics: Biology , Medicine
    Published by PeerJ
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  • 4
    Publication Date: 2019-06-11
    Description: Background Acetyl-CoA carboxylase (ACC) plays an important role in the metabolism of various cancer cells, but its role in head and neck squamous cell carcinoma (HNSCC) is uncertain. Therefore, in the present study, we explored the role of ACC2 in HNSCC. Methods Western blot and immunohistochemistry assays were used to determine ACC2 protein expression levels in laryngocarcinoma and adjacent normal tissues derived from patients with laryngocarcinoma. ACC2 expression was knocked down in the hypopharyngeal cancer cell line FaDu to determine its effect on apoptosis. Lipid oil red staining was used to test the change of intracellular lipid. Results The results showed that the ACC2 protein was highly expressed in laryngocarcinoma and that the ACC2 expression level was positively associated with the clinical cancer stage and negatively associated with the degree of laryngocarcinoma cell differentiation. Kaplan–Meier analyses indicated that compared with patients having low levels of ACC2, those with high ACC2 levels had a decreased 5-year survival rate. The results of western blot and terminal deoxynucleotidyl transferase dUTP nick-end labeling assays showed that knockdown of ACC2 accelerated apoptosis in FaDu cells. Furthermore, knockdown of ACC2 significantly reduced the intracellular lipid levels in FaDu cells. Conclusion These findings suggest that ACC2 may be an important prognostic marker for patients with HNSCC and that ACC2 may be a potential target in the treatment of HNSCC.
    Electronic ISSN: 2167-8359
    Topics: Biology , Medicine
    Published by PeerJ
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  • 5
    Publication Date: 2020-10-13
    Description: The pathology of cerebrovascular disorders, such as hypertension, is associated with genetic changes and dysfunction of basilar artery smooth muscle cells (BASMCs). Long-term high-salt diets have been associated with the development of hypertension. However, the molecular mechanisms underlying salt-sensitive hypertension-induced BASMC modifications have not been well defined, especially at the level of variations in gene transcription. Here, we utilized high-throughput sequencing and subsequent signaling pathway analyses to find a two–fold change or greater upregulated expression of 203 transcripts and downregulated expression of 165 transcripts in BASMCs derived from rats fed a high-salt diet compared with those from control rats. These differentially expressed transcripts were enriched in pathways involved in cellular, morphological, and structural plasticity, autophagy, and endocrine regulation. These transcripts changes in the BASMCs derived from high-salt intake–induced hypertensive rats may provide critical information about multiple cellular processes and biological functions that occur during the development of cerebrovascular disorders and provide potential new targets to help control or block the development of hypertension.
    Electronic ISSN: 2167-8359
    Topics: Biology , Medicine
    Published by PeerJ
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  • 6
    Publication Date: 2017-12-22
    Description: Background Phylogenetic relationship within different genera of Lemnoideae, a kind of small aquatic monocotyledonous plants, was not well resolved, using either morphological characters or traditional markers. Given that rich genetic information in chloroplast genome makes them particularly useful for phylogenetic studies, we used chloroplast genomes to clarify the phylogeny within Lemnoideae. Methods DNAs were sequenced with next-generation sequencing. The duckweeds chloroplast genomes were indirectly filtered from the total DNA data, or directly obtained from chloroplast DNA data. To test the reliability of assembling the chloroplast genome based on the filtration of the total DNA, two methods were used to assemble the chloroplast genome of Landoltia punctata strain ZH0202. A phylogenetic tree was built on the basis of the whole chloroplast genome sequences using MrBayes v.3.2.6 and PhyML 3.0. Results Eight complete duckweeds chloroplast genomes were assembled, with lengths ranging from 165,775 bp to 171,152 bp, and each contains 80 protein-coding sequences, four rRNAs, 30 tRNAs and two pseudogenes. The identity of L. punctata strain ZH0202 chloroplast genomes assembled through two methods was 100%, and their sequences and lengths were completely identical. The chloroplast genome comparison demonstrated that the differences in chloroplast genome sizes among the Lemnoideae primarily resulted from variation in non-coding regions, especially from repeat sequence variation. The phylogenetic analysis demonstrated that the different genera of Lemnoideae are derived from each other in the following order: Spirodela, Landoltia, Lemna, Wolffiella, and Wolffia. Discussion This study demonstrates potential of whole chloroplast genome DNA as an effective option for phylogenetic studies of Lemnoideae. It also showed the possibility of using chloroplast DNA data to elucidate those phylogenies which were not yet solved well by traditional methods even in plants other than duckweeds.
    Electronic ISSN: 2167-8359
    Topics: Biology , Medicine
    Published by PeerJ
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