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  • 1
    Language: English
    In: Tribology Letters, 2013, Vol.52(1), pp.47-55
    Description: In the present paper, the influence of load and sliding speed on super-low friction of Nitinol 60 alloy was investigated experimentally using Nitinol 60 alloy pin sliding over GCr15 steel disk under castor oil lubrication. Super-low coefficient of friction (COF) of Nitinol 60 alloy was achieved at the stable state, corresponding to so-called superlubricity regime in the presence of castor oil. The experimental results indicate that sliding speed employed in the friction tests plays great roles in the lubrication behaviors of Nitinol 60 alloy. When the friction tests are executed from low sliding speed to high sliding speed, COF decreases at the initial stage and on the contrary, COF increases at the stable stage. However, with the increase in load, COF firstly increases and then decreases at the initial stage. COF is unstable but still super low and remains almost the same value at the stable stage. These phenomena are explained and discussed in viewpoint of the characteristics of castor oil during the friction tests. It is found that the influence of sliding speed on the lubrication behaviors of Nitinol 60 alloy under castor oil lubrication is more obvious than that of load due to the characteristics structure of castor oil, therefore maintaining appropriate level of sliding speed to achieve super-low friction of Nitinol 60 alloy.
    Keywords: Super-low friction ; Nitinol 60 alloy ; Castor oil ; Test parameters ; Lubrication behaviors
    ISSN: 1023-8883
    E-ISSN: 1573-2711
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  • 2
    Language: English
    In: Journal of Global Optimization, 2002, Vol.22(1), pp.365-375
    Description: We describe a linear-time algorithm for solving the molecular distance geometry problem with exact distances between all pairs of atoms. This problem needs to be solved in every iteration of general distance geometry algorithms for protein modeling such as the EMBED algorithm by Crippen and Havel ( Distance Geometry and Molecular Conformation , Wiley, 1988). However, previous approaches to the problem rely on decomposing an distance matrix or minimizing an error function and require O(n 2 ) to O( 3 ) floating point operations. The linear-time algorithm will provide a much more efficient approach to the problem, especially in large-scale applications. It exploits the problem structure and hence is able to identify infeasible data more easily as well.
    Keywords: Molecular distance geometry ; Protein structure determination ; Numerical linear algebra and optimization
    ISSN: 0925-5001
    E-ISSN: 1573-2916
    Source: Springer Science & Business Media B.V.
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  • 3
    Language: English
    In: Journal of Global Optimization, 2003, Vol.26(3), pp.321-333
    Description: Nuclear magnetic resonance (NMR) structure modeling usually produces a sparse set of inter-atomic distances in protein. In order to calculate the three-dimensional structure of protein, current approaches need to estimate all other “missing” distances to build a full set of distances. However, the estimation step is costly and prone to introducing errors. In this report, we describe a geometric build-up algorithm for solving protein structure by using only a sparse set of inter-atomic distances. Such a sparse set of distances can be obtained by combining NMR data with our knowledge on certain bond lengths and bond angles. It can also include confident estimations on some “missing” distances. Our algorithm utilizes a simple geometric relationship between coordinates and distances. The coordinates for each atom are calculated by using the coordinates of previously determined atoms and their distances. We have implemented the algorithm and tested it on several proteins. Our results showed that our algorithm successfully determined the protein structures with sparse sets of distances. Therefore, our algorithm reduces the need of estimating the “missing” distances and promises a more efficient approach to NMR structure modeling.
    Keywords: Molecular distance geometry ; Protein structure determination ; Numerical linear algebra and optimization
    ISSN: 0925-5001
    E-ISSN: 1573-2916
    Source: Springer Science & Business Media B.V.
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  • 4
    Language: English
    In: International Urogynecology Journal, 2018, Vol.29(12), pp.1765-1771
    Keywords: Microbiome ; Urinary incontinence ; Bladder ; Urinary symptoms
    ISSN: 0937-3462
    E-ISSN: 1433-3023
    Source: Springer Science & Business Media B.V.
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  • 5
    Language: English
    In: International Urogynecology Journal, 2018, Vol.29(12), pp.1797-1805
    Keywords: Urinary tract infection ; Urobiome ; Surgical infection ; Postoperative infection
    ISSN: 0937-3462
    E-ISSN: 1433-3023
    Source: Springer Science & Business Media B.V.
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  • 6
    Language: English
    In: International Urogynecology Journal, 2019, Vol.30(8), pp.1261-1267
    Description: INTRODUCTION AND HYPOTHESISPresence of microbial communities (microbiota) in an organ system depends on environmental factors, such as oxygen availability. We describe a novel technique to measure bladder urine oxygen tension (BUOT) in ambulatory women and use that technique to compare BUOT values to female urinary microbiota and participant urinary signs and symptoms. METHODSAmbulatory female urogynecology patients presenting for clinical care who were willing to undergo transurethral catheterization underwent BUOT determination with a non-invasive flow-through oxygen sensor. To detect urinary microbiota in the bladder, 16S rRNA gene sequencing was performed on catheterized urine. Multivariate statistical analyses were performed to examine potential correlations among BUOT, urinary microbiota compositions and clinical variables. RESULTSSignificant variation in BUOT existed between individuals (range: 0.47-51.5 mmHg; median: 23.1 ± 13.5). Microbiota compositions were associated with BUOT (p = 0.03). BUOT was significantly lower in urines that were nitrite negative on dipstick analysis (p = 0.0001) and in participants who answered yes to having urinary leakage on the validated Urinary Distress Inventory (p = 0.01). CONCLUSIONSBUOTs can be measured in ambulatory women. For urogynecology patients, a wide range of values exist. BUOT may be associated with the presence of urinary microbiota and resultant signs and symptoms.
    Keywords: Human microbiome ; Urinary bladder ; Oxygen tension
    ISSN: 0937-3462
    E-ISSN: 1433-3023
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  • 7
    Language: English
    In: Journal of Materials Science, 2014, Vol.49(6), pp.2662-2671
    Description: Osteoblast responses to Co–Cr–Mo alloy depend on not only the chemistry of alloy but also the physical properties of alloy surface, such as its microtopography and roughness. This study was undertaken to examine changes in cell adhesion, morphology, differentiation and gene expression during osteoblast interaction with different textured Co–Cr–Mo alloys. With laser surface texturing, three kinds of textured surfaces were fabricated. It showed that the microenvironment processed by laser surface texturing leads to an increase in surface roughness and DMEM contact angles of samples. Adhesion and differentiation tests demonstrated that osteoblast cells can discriminate surfaces with different roughness and surfaces with comparable roughness but different topographies such as triangle, circle and square textures. Morphological characteristics obtained by SEM imaging showed that osteoblast cells are elongated and are in polygonal shape on the textured surface. OPG/RANKL mRNA expression studies showed a significant and marked decrease in RANKL gene expression on the square-textured surface; by contrast, the ratio of OPG/RANKL showed a significant increase. These results indicate that Co–Cr–Mo surface textures affect osteoblast proliferation, morphology and gene expression; the microenvironment of implant should be considered in the future design.
    Keywords: Alloys ; Specialty Metals Industry ; Gene Expression ; RNA;
    ISSN: 0022-2461
    E-ISSN: 1573-4803
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  • 8
    Language: English
    In: Tribology Letters, 2015, Vol.60(2), pp.1-12
    Description: The lubrication mechanism of nanoinorganic particles during friction process has been widely investigated. However, the physical adsorption action mechanism between the nanoparticles (after modification) and friction pairs has so far never been studied in detail. In this study, the various concentrations of polyisobutyleneamine succinimide (PIBS) by weight in paraffin oil were applied to study their effect on the tribological behaviors of nano-MoS 2 oil. And the tribological results were further discussed to understand the lubricating action mechanism of nano-MoS 2 particles additive. The results show that the tribological behavior of modified nanoparticles was significantly influenced by PIBS concentration. The COF reduced from 0.139 to 0.090 with low PIBS concentration (less than 0.1 wt%), while the COF reduced to 0.126 with higher PIBS concentration (more than 0.2 wt%). By scanning electron microscopic (SEM) and energy-dispersive X-ray spectroscopy, some mechanisms likely related to this interesting results are revealed. It is identified that: (1) production of MoS 2 tribofilm on steel surface reduces the COF and wear, (2) wear scar is smooth with low PIBS concentration, while it shows plowing wear with high PIBS concentration, (3) the MoS 2 tribofilm is found by SEM on the wear scar of the nano oil with 0.05 wt% PIBS. A three-step lubricating action mechanism of the modified nano-MoS 2 particles has been proposed as an explanation for the interesting results. The results indicate that physical adsorption provide an initial action for nanoparticle lubricant to form tribofilm in boundary lubrication.
    Keywords: MoS ; Nanoparticles ; Physical adsorption ; Lubricating action mechanism ; Oil
    ISSN: 1023-8883
    E-ISSN: 1573-2711
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  • 9
    Language: English
    In: Plant Molecular Biology, 2011, Vol.77(3), pp.225-233
    Description: Allopolyploidization is considered an essential evolutionary process in plants that could trigger genomic shock in allopolyploid genome through activation of transcription of retrotransposons, which may be important in plant evolution. Two retrotransposon-based markers, inter-retrotransposon amplified polymorphism and retrotransposon-microsatellite amplified polymorphism and a microsatellite-based marker, inter simple sequence repeat were employed to investigate genomic changes in early generations of a newly synthesized allotetraploid Cucumis  ×  hytivus Chen & Kirkbride (2n = 4 x  = 38) which was derived from crossing between cultivated cucumber C. sativus L. (2n = 2 x  = 14) and its wild relative C. hystrix Chakr. (2n = 2 x  = 24). Extensive genomic changes were observed, most of which involved the loss of parental DNA fragments and gain of novel fragments in the allotetraploid. Among the 28 fragments examined, 24 were lost while four were novel, suggesting that DNA sequence elimination is a relatively frequent event during polyploidization in Cucumis . Interestingly, of the 24 lost fragments, 18 were of C. hystrix origin, four were C. sativus -specific, and the remaining two were shared by both species, implying that fragment loss may be correlated with haploid DNA content (genome size) of diploid parents. Most changes were observed in the first generation after polyploidization (S 1 ) and stably inherited in the subsequent three generations (S 2 –S 4 ), indicating that genomic changes might be a rapid driving force for the stabilization of allotetraploids. Sequence analysis of 11 of the 28 altered DNA fragments showed that genomic changes in the allotetraploid occurred in both coding and non-coding regions, which might suggest that retrotransposons inserted into genome randomly and had a genome-wide effect on the allotetraploid evolution. Fluorescence in situ hybridization (FISH) analysis revealed a unique distribution of retrotransposon and/or microsatellite flanking sequences in mitotic and meiotic chromosomes, where the preferential FISH signals occurred in the centromeric and telomeric regions, implying that these regions were the possible hotspots for genomic changes.
    Keywords: Polyploidization ; Evolution ; Retrotransposon ; Cucumis ; IRAP ; REMAP ; Fluorescence in situ hybridization (FISH)
    ISSN: 0167-4412
    E-ISSN: 1573-5028
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