265 research outputs found

    Circ-0000979 promotes the development of gastric carcinoma by sponging miR-136 and modulating SP1 mRNA expression level

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    Circular RNAs (circRNAs) are a new class of non-coding RNAs that play pivotal biological roles in several types of cancer cells. However, the role of circ0000979 in gastric cancer (GC) has never been explored. Therefore, the current study aims to examine the functional effects of circ-0000979 in GC development and progression. The expression level of circ-0000979 was validated using qRT-PCR analysis. We found that circ-0000979 is significantly upregulated in GC samples. Using AGS and HGC27 GC cell line, we examined the biological functions and regulatory mechanisms of circ0000979 in GC in vitro and in vivo by knocking down circ-0000979. We found that circ-0000979 is subcellularly localized in the cytoplasm of GC cells. Functionally, silencing circ-0000979 leads to a significant reduction in GC cell proliferation and migration. In vivo assays showed that circ-0000979 knockdown markedly reduced GC tumor growth. CircRNA interactome predicted miR-136 as circ0000979 targeting miRNA, while starbase prediction result showed that miR-136 targeted the 3’UTR region of SP1 mRNA. Taken together, our results demonstrated that circ-0000979, as a carcinogenic circRNA, promotes the progression of GC by regulating the miR-136/SP1 pathway. Circ-0000979 is a potential RNA-based therapeutic target for GC treatment

    Evaluation of Multiple Corrosion Protection Systems and Corrosion Inhibitors for Reinforced Concrete Bridge Decks

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    The corrosion performance of different corrosion protection systems is evaluated using the mortar-wrapped rapid macrocell test, bench-scale tests (the Southern Exposure, cracked beam, and ASTM G109 tests), and field tests. The systems include conventional steel with three different corrosion inhibitors (DCI-S, Hycrete, and Rheocrete), epoxy-coated reinforcement with three different corrosion inhibitors and ECR with a primer coating containing microencapsulated calcium nitrite, multiple-coated reinforcement with a zinc layer underlying an epoxy coating, ECR with zinc chromate pretreatment before application of the epoxy coating to improve adhesion between the epoxy and the underlying steel, ECR with improved adhesion epoxy coatings, and pickled 2205 duplex stainless steel. Conventional steel in concretes with two different water-cement ratios (0.45 and 0.35) is also tested. Of these systems, specimens containing conventional steel or conventional epoxy-coated steel serve as controls. The critical chloride thresholds of conventional steel in concrete with different corrosion inhibitors and zinc-coated reinforcement are determined. The results of the tests are used in an economic analysis of bridge decks containing different corrosion protection systems over a design life of 75 years. The results indicate that a reduced water-cement ratio improves the corrosion resistance of conventional steel in uncracked concrete compared to the same steel in concrete with a higher water-cement ratio. The use of a corrosion inhibitor improves the corrosion resistance of conventional steel in both cracked and uncracked concrete and delays the onset of corrosion in uncracked concrete, but provides only a very limited improvement in the corrosion resistance of epoxy-coated reinforcement due to the high corrosion resistance provided by the epoxy coating itself. Based on results in the field tests, the epoxy-coated bars with a primer containing microencapsulated calcium nitrite show no improvement in the corrosion resistance compared to conventional epoxy-coated reinforcement. Increased adhesion between the epoxy coating and reinforcing steel provides no improvement in the corrosion resistance of epoxy-coated reinforcement. The corrosion losses for multiple-coated reinforcement are comparable with those of conventional epoxy-coated reinforcement in the field tests in uncracked and cracked concrete. Corrosion potential measurements show that the zinc is corroded preferentially, providing protection for the underlying steel. Pickled 2205 stainless steel demonstrates excellent corrosion resistance, and no corrosion activity is observed for the pickled 2205 stainless steel in bridge decks, or in the SE, CB, or field test specimens after four years. ECR, ECR with increased adhesion, and pickled 2205 stainless steel are the most cost-effective corrosion protection systems based on the economic analyses of a 216-mm (8.5-in.) thick bridge deck over a 75-year design life

    Evaluation of Multiple Corrrosion Protection Systems and Corrosion Inhibitors for Reinforced Concrete Bridge Decks

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    The corrosion performance of different corrosion protection systems is evaluated using the mortar-wrapped rapid macrocell test, bench-scale tests (the Southern Exposure, cracked beam, and ASTM G109 tests), and field tests. The results indicate that a reduced water-cement ratio improves the corrosion resistance of conventional steel in uncracked concrete. The use of a corrosion inhibitor improves the corrosion resistance of conventional steel in both cracked and uncracked concrete, but provides only a very limited improvement in the corrosion resistance of epoxy-coated reinforcement. Increased adhesion between the epoxy coating and reinforcing steel provides no improvement in the corrosion resistance of epoxy-coated reinforcement. The corrosion losses for multiple-coated reinforcement are comparable with those of conventional epoxy-coated reinforcement. Pickled 2205 stainless steel demonstrates excellent corrosion resistance. ECR, ECR with increased adhesion, and pickled 2205 stainless steel are the most cost-effective corrosion protection systems based on the economic analyses of a 216-mm (8.5-in.) thick bridge deck over a 75-year design life

    Case for Changing Reinforcing Bar Deformation Spacing Requirements

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    The bond strength of four sets of reinforcing bars is evaluated, two each with No. 5 and No. 10 (No. 16 and No. 32) bars, which have, respectively, nominal diameters of 0.625 and 1.27 in. (15.9 and 32.3 mm). One bar of each size satisfies the criterion for maximum deformation spacing in ASTM reinforcing bar specifications, while the other has deformations that exceed the maximum spacing. All bars exceed the requirements for minimum deformation height. Research related to the effect of deformation properties on bond strength, including the research used to establish the requirements for deformations in ASTM reinforcing bar specifications, is also reviewed. The test results match earlier research and demonstrate that (1) bond strength is not governed by the specific value of deformation height or spacing, but by the combination of the two as represented by the relative rib area of the bars and (2) the bond strength of the bars with deformation spacings that exceed those in ASTM reinforcing bar specifications is similar to the bond strength of the bars that meet the specification. Based on this and prior research, it is recommended that ASTM reinforcing bar specifications be modified to allow for deformation spacing up to 90 % (currently a maximum of 70 %) of the bar diameter provided the ratio of deformation height to deformation spacing is greater than or equal to the minimum ratio for bar deformations meeting the current requirements in ASTM reinforcing bar specifications.Nucor Corporatio

    Critical Chloride Corrosion Threshold for Galvanized Reinforcing Bars

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    Galvanized reinforcement is evaluated to determine the chloride content required for corrosion initiation. The bars conform to ASTM A 767, except that no chromate treatment was applied. Specimens containing the galvanized bars are subjected to Southern Exposure test conditions that are terminated upon corrosion initiation, after which the chloride content at the level of the reinforcement is determined. These data are compared with chloride surveys performed on bridge decks to obtain an average time to corrosion initiation. The time to corrosion initiation for galvanized reinforcement is compared to conventional reinforcement and MMFX Microcomposite reinforcement. The galvanized reinforcement specimens were also examined after testing for signs of hydrogen formation. The test results show that galvanized reinforcement has an average critical chloride corrosion threshold of 2.57 lb/yd3, which is greater than conventional steel (1.63 lb/yd3) and lower than MMFX steel (6.34 lb/yd3). Galvanized reinforcement exhibits a wider range of values of chloride content at corrosion initiation than conventional reinforcement. Critical corrosion threshold values for galvanized reinforcement range from values comparable to those exhibited by conventional steel to values three to four times that of conventional steel. Autopsy results revealed zinc corrosion products on the bars. Hydrogen gas evolution did not appear to increase the porosity of the concrete in the non-chromate treated bars relative to conventional reinforcement in air-entrained concrete. Some galvanized bars, however, showed signs of corrosion, including loss of the pure zinc layer, which may be due to the lack of chromate treatment or due to loss of metal in presence of high-pH concrete pore solution. Based on chloride surveys of cracked bridge decks in Kansas, galvanized steel can be expected to increase the average time to corrosion initiation at crack locations from 2.3 years for conventional steel to 4.8 years for bars with 3 in. of concrete cover. Corrosion initiation can be expected to occur at an average age of 14.8 years for MMFX steel. All three systems will exhibit significantly longer times to corrosion initiation in uncracked concrete

    Critical Chloride Corrosion Threshold of Galvanized Reinforcing Bars

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    The chloride content required for corrosion initiation of galvanized reinforcing bars is determined. The bars conform to ASTM A767, except that no chromate treatment was applied to allow the degree of hydrogen evolution for untreated bars to be evaluated. Test results, along with results for conventional (ASTM A615), low carbon chromium (ASTM A1035, MMFX), and 316LN stainless steel reinforcement are compared with chloride surveys of bridge decks to obtain an average time to corrosion initiation. The average critical chloride corrosion threshold of galvanized reinforcement is greater than the threshold for conventional steel and lower than the threshold for ASTM A1035 and 316LN steel. Hydrogen gas evolution did not increase the porosity of the concrete in the non-chromate treated bars relative to that observed for conventional reinforcement. The average time to corrosion initiation at crack locations in bridge decks for galvanized steel is 4.8 years, compared with 2.3 years for conventional steel, and 15 years for ASTM A1035 steel. 316LN stainless steel will not corrode

    Big-Data Based Analysis for Communication Effect of Science-Technology Public Accounts On Social Media

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    Public accounts on social media have become important channels for information dissemination. Well-designed public social media accounts are vital to better communicate science and technology (S-T) achievements. This article defines the S-T communication concept and proposes the analyzing dimensions. In order to measure the communication effect, this research collected 7,246 articles from S-T public accounts on WeChat. We analysis these massive data incorporating neural network (NN) and multivariate linear regression (MLR) model. The evaluation indicator system of communication effect includes three levels indicators. The research found the following factors affecting the S-T communication effect in different degrees: the number of active fans on Science Technology Public Accounts on Social Media (STPA-SM), locations where the articles are published, the authentication status of STPA-SM, and so on. Finally, the article proposes some strategic suggestions for improving the communication effects of S-T achievements through STPA-SM

    Effect of Corrosion Inhibitors on Concrete Pore Solution Composition and Corrosion Resistance

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    Three commercially available corrosion inhibitors—calcium nitrite, a solution of amines and esters, and an alkenyl-substituted succinic acid salt—are evaluated in conjunction with conventional reinforcement in concrete based on corrosion rate, metal loss, the critical chloride corrosion threshold (CCCT), pore solution analyses, and concrete compressive strength. All three inhibitors increase time to corrosion initiation and decrease corrosion rate, but are less effective in cracked concrete than in uncracked concrete. Of the three inhibitors, the alkenyl-substituted succinic acid salt results in the greatest decrease in corrosion rate, but exhibits the lowest CCCT—below that measured in concrete with no inhibitor. The compressive strengths of concretes containing the amine-ester inhibitor and the alkenyl-substituted succinic acid salt were 15% and 60% lower, espectively, than concrete without an inhibitor. For the latter inhibitor, pore solution analyses indicated elevated sulfate contents at 1 and 7 days, which may explain the low CCCT and strength. Paste containing the amine-ester inhibitor had an elevated sulfate content at 7 days
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