Fire and post-fire performance of circular steel tube confined reinforced concrete columns

[EN] Fire and post-fire behaviours of reinforced concrete columns confined by circular steel tubes, also known as circular steel tube confined reinforced concrete (STCRC) columns, are investigated in this paper. 5 full-scale specimens exposed to fire and 47 specimens after fire exposure were tested. Temperatures across the sections, displacement versus time curves, fire resistance, load versus displacement responses and load-bearing capacities were measured and discussed. A finite element (FE) model was developed using the program ABAQUS, and validated against the test results from the present study. Simplified design methods were proposed for predicting the fire resistance and residual load-bearing capacity of the STCRC columns under and after fire exposure, respectively.The research presented in this paper was sponsored by the National Natural Science Foundation (No. 51508131), the Fundamental Research Funds for the Central Universities (HIT.NSRIF.201860), China Postdoctoral Science Foundation (No.2016M591535); their financial support is highly appreciated.Liu, F.; Yang, H.; Zhang, S. (2018). Fire and post-fire performance of circular steel tube confined reinforced concrete columns. En Proceedings of the 12th International Conference on Advances in Steel-Concrete Composite Structures. ASCCS 2018. Editorial Universitat Politècnica de València. 787-793. https://doi.org/10.4995/ASCCS2018.2018.7002OCS78779

Local Buckling Analysis of T-Section Webs with Closed-Form Solutions

This paper reports on approaches to estimate the critical buckling loads of thin-walled T-sections with closed-form solutions. We first develop a model using energy conservation approach under the assumption that there is no correlation between the restraint coefficient and buckling half-wavelength. Secondly, we propose a numerical approach to estimate the critical buckling conditions under the more realistic torsional stiffener constraint condition. A dimensionless parameter correlated with constraint conditions is introduced through finite element (FE) analysis and data fitting technique in the numerical approach. The critical buckling coefficient and loads can be expressed as explicit functions of the dimensionless parameter. The proposed numerical approach demonstrates higher accuracy than the approach under noncorrelation assumption. Due to the explicit expression of critical buckling loads, the numerical approach presented here can be easily used in the design, analysis, and precision manufacture of T-section webs

Hexa-μ2-acetato-triaqua-μ3-oxido-triiron(III) nitrate acetic acid solvate

The asymmetric unit of the title compound, [Fe3(CH3COO)6O(H2O)3]NO3·CH3COOH, consists of a hexa-μ2-acetato-triaqua-μ3-oxo-triiron(III) macrocation, a nitrate ion and an acetic acid solvent mol­ecule. In the cation, each Fe3+ ion is coordinated by four carboxyl­ate O atoms, one central bridged O atom and one water mol­ecule, resulting in distorted FeO6 octa­hedra. A network of O—H⋯O hydrogen bonds helps to establish the packing

Analysis of m6A methylation expression profiles in liver tissue of high-fat diet-induced mouse models of NAFLD

Objective·To detect the differences in m6A methylation modification and gene expression of liver tissue mRNA in high-fat diet-induced mouse models of non-alcoholic fatty liver disease (NAFLD) using microarray technology.Methods·The NAFLD models were established in 6-8 weeks old male C57BL/6J mice fed with high-fat chow for 16 weeks (high-fat group, n=10). The basal group (n=10) was given 10% fat diet. Hematoxylin-eosin (H-E) staining was used to assess the histopathological changes in liver tissue and to determine the success of the NAFLD models. The changes of mRNA m6A methylation and expression levels in the liver tissues of the two groups were detected by using methylated RNA immunoprecipitation (MeRIP) and microarray expression profiling.Results·The livers of the mice in the basal group were bright red with few fat deposits, while the livers of the mice in the high-fat group were yellowish with diffuse infiltration and fusion of lipid droplets in the hepatocytes by H-E staining, suggesting that the high-fat diet-induced NAFLD models were successfully constructed. The results of the MeRIP-microarray showed that the m6A methylation levels of 320 genes in the livers of mice in the high-fat group were significantly altered compared with those in the basal group (P1.5), of which 108 genes were up-regulated and 212 genes were down-regulated. Genes with significant differences in m6A methylation levels between the two groups were intersected with those with differentially expressed mRNAs, and 163 genes were found to have significant differences in both m6A methylation level and mRNA expression level.Conclusion·The change in m6A modification of liver tissue mRNA in the high-fat diet-induced mouse models of NAFLD is significant and the change is associated with the gene expression of mRNA

Role of extrathyroidal TSHR expression in adipocyte differentiation and its association with obesity

<p>Abstract</p> <p>Background</p> <p>Obesity is known to be associated with higher risks of cardiovascular disease, metabolic syndrome, and diabetes mellitus. Thyroid-stimulating hormone (TSHR) is the receptor for thyroid-stimulating hormone (TSH, or thyrotropin), the key regulator of thyroid functions. The expression of TSHR, once considered to be limited to thyrocytes, has been so far detected in many extrathyroidal tissues including liver and fat. Previous studies have shown that TSHR expression is upregulated when preadipocytes differentiate into mature adipocytes, suggestive of a possible role of TSHR in adipogenesis. However, it remains unclear whether TSHR expression in adipocytes is implicated in the pathogenesis of obesity.</p> <p>Methods</p> <p>In the present study, TSHR expression in adipose tissues from both mice and human was analyzed, and its association with obesity was evaluated.</p> <p>Results</p> <p>We here showed that TSHR expression was increased at both mRNA and protein levels when 3T3-L1 preadipocytes were induced to differentiate. Knockdown of TSHR blocked the adipocyte differentiation of 3T3-L1 preadipocytes as evaluated by Oil-red-O staining for lipid accumulation and by RT-PCR analyses of PPAR-γ and ALBP mRNA expression. We generated obesity mice (C57/BL6) by high-fat diet feeding and found that the TSHR protein expression in visceral adipose tissues from obesity mice was significantly higher in comparison with the non-obesity control mice (<it>P </it>< 0.05). Finally, the TSHR expression in adipose tissues was determined in 120 patients. The results showed that TSHR expression in subcutaneous adipose tissue is correlated with BMI (body mass index).</p> <p>Conclusion</p> <p>Taken together, these results suggested that TSHR is an important regulator of adipocyte differentiation. Dysregulated expression of TSHR in adipose tissues is associated with obesity, which may involve a mechanism of excess adipogenesis.</p

A new perspective for assessing water transport and associated retention effects in a large reservoir

Author Posting. © American Geophysical Union, 2018. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 45 (2018): 9642-9650, doi:10.1029/2018GL079687.Radioactive tracer techniques may be useful for assessing water transport and the overall effects of concurrent biogeochemical processes in river‐reservoir systems. In this study, we show that radium isotopes can assess the hydrodynamics and sediment/nutrient retention in the Xiaolangdi Reservoir, the largest impoundment along the Yellow River, China. Activity ratios of 224Ra/226Ra and 223Ra/226Ra were used for water mass age calculations in the riverine, transition, and lentic reaches of the reservoir. Water ages were combined with the length scale of three river‐reservoir zones to determine water transport rates of 3.6 ± 1.2, 1.3 ± 0.3, and 0.16 ± 0.14 km/day, respectively. Radium ages were also used to quantify the net retention of sediment and nutrients in different parts of the river‐reservoir system. Suspended sediment was removed at a rate of 1.4 ± 0.6 g/m3/day, mainly in the riverine zone. Nutrient dynamics were more complicated, with addition or removal at different rates within the three zones.Ministry of Education of the People's Republic of China Grant Number: MS2014ZGHY028; Qingdao National Laboratory for Marine Science and Technology Grant Number: 2016ASKJ02; National Science Foundation of China Grant Numbers: 41521064, 41876075, 41576075; Ministry of Science and Technology of the People's Republic of China Grant Number: 2016YFA06009022019-03-2

A porcine gene, PBK, differentially expressed in the longissimus muscle from Meishan and Large White pig

An investigation of differences in gene expression in the longissimus muscle of Meishan and Large White pigs was undertaken, using the mRNA display technique. A fragment of one differentially expressed gene was isolated and sequenced, whereupon the complete cDNA sequence was then obtained by using the rapid amplification of cDNA ends (RACE). The nucleotide sequence of the gene is not related to any known porcine gene. Sequence analysis revealed that the open reading frame of this gene encodes a protein with 322 amino acids, thus displaying high sequence identity with the PDZ binding kinase (PBK) of eleven other animal species – dog, horse, cattle, human, chimpanzee, crab-eating macaque, rhesus monkey, rat, mouse, gray short-tailed opossum and platypus, so it can be defined as the porcine PBK gene. This gene was finally assigned GeneID:100141310. Phylogenetic tree analysis revealed that the swine PBK gene has a closer genetic relationship with the PBK gene of platypus. Gene expression analysis of eight tissues of a Meishan x Large White cross showed that the porcine PBK gene is differentially expressed in various tissues. Our experiment established the primary foundation for further research on this gene

Shear degradation of corn starches with different amylose contents

This work investigated the effect of shear on the starch degradation, with a particular focus on the changes in molecular and lamellar structures. Corn starches with different amylose/amylopectin ratios (waxy corn starch, or WCS: 1:99; normal corn starch, or NCS: 25:75; and Gelose 80 starch, or G80: 80:20) were used as model materials to be processed using a Haake twin-rotor mixer for different times. Molecular and lamellar structural analysis was performed using size-exclusion chromatography (SEC) and small-angle X-ray scattering (SAXS). The degree of damage of starch at the granule level was evaluated by an assay kit. The results showed that amylose molecules in starch granules did not change significantly, while amylopectin molecules degraded to a stable size caused by the shear treatment. The average thickness of semi-crystalline lamellae disappeared rapidly during processing. A typical positive deviation from Porod's law at a high q region was observed, attributed to the presence of thermal density fluctuations or mixing within phases. Nonetheless, the degree of mixing within phases for the processed samples was lower than the native starch. The study of the mass fractal structure indicated that the scattering objects of the processed starches were more compact than those of the native counterparts. Furthermore, waxy corn starch (containing mostly amylopectin) experienced the greatest granule damage than the other starches. All the results showed that the rigid crystal structure in amylopectin is more sensitive to the shear treatment than the flexible amorphous structure in amylose. This mechanistic understanding at the microstructure level is helpful in designing the processing of starch-based foods or plastics with desired functional properties

Distribution and off–shelf transport of dissolved manganese in the East China Sea

To gain a better understanding of the geochemical behavior of dissolved manganese (Mn) in the marginal seas with respect to distribution and exchange fluxes, more than 200 water samples were collected in the East China Sea (ECS) in May, August, and October of 2013. The concentration of dissolved Mn in the ECS ranged from 1.1 to 81.5 nM, with a gradual decrease with distance from the shore. Seasonal distribution of dissolved Mn varies significantly in the Changjiang estuary, mainly regulated by freshwater input from the Changjiang (Yangtze River) and redox variations. The ECS continental shelf is an important source of Mn for adjacent waters, and the export of Mn–rich coastal waters had an important effect on its re-distribution and internal cycling. The dynamic variation fluxes of water and dissolved Mn across the 100– and 200–m isobaths in the ECS were calculated with an aid of the Finite−Volume Coastal Ocean Model (FVCOM). The ECS continental shelf exported (5.69 ± 1.14) × 108 mol/yr of Mn into the East/Japan Sea from the Tsushima Strait. The Kuroshio surface waters receive an additional (1.02 ± 3.12) × 108 mol/yr of Mn from the ECS continental shelf through a cross–shelf exchange process, which could potentially affect dissolved Mn in the Northwest Pacific. Our data suggest that off-shelf transport from the ECS continental shelf is essential for understanding the biogeochemical cycles of trace metals in the Northwest Pacific Ocean and the East/Japan Sea