Analysis of Shear Model for Steel-Fiber-Reinforced High-Strength Concrete Corbels with Welded-Anchorage Longitudinal Reinforcement.

According to the shear capacity test results of six steel-fiber-reinforced high-strength concrete (SFHSC) corbels with welded-anchorage longitudinal reinforcement under concentrated load, the effects of shear span ratio and steel fiber volume fraction on the failure mode, cracking load and ultimate load of corbel specimens were analyzed. On the basis of experimental research, the shear transfer mechanism of corbel structure was discussed. Then, a modified softened strut-and-tie model (MSSTM), composed of the diagonal and horizontal mechanisms, was proposed, for steel-fiber-reinforced high-strength concrete corbels. The contributions of concrete, steel fiber and horizontal stirrups to the shear bearing capacity of the corbels were clarified. A calculation method for the shear bearing capacity of steel-fiber-reinforced high-strength concrete corbels was established and was simplified on this basis. The calculation results of the model were compared with the test values and calculation results of the GB50010-2010 code, the ACI318-19 code, the EN 1992-1-1 code and the CSA A23.3-19 code. The results showed that the concrete corbel with small shear span ratio mainly has two typical failure modes: shear failure and diagonal compression failure. With the increase in shear span ratio, the shear capacity of corbels decreases. Steel fiber can improve the ductility of a reinforced concrete corbel, but has little effect on the failure mode of the diagonal section. The calculated values of the national codes were lower than the experimental values, and the results were conservative. The theoretical calculation values of the shear capacity calculation model of the corbels were close to the experimental results. In addition, the model has a clear mechanical concept considering the tensile properties of steel-fiber-reinforced high-strength concrete and the influence of horizontal stirrups, which can reasonably reflect the shear transfer mechanism of corbels.

[Chemical composition analysis and value evaluation of stems and leaves of Astragalus membranaceus var. mongholicus].

This study aimed to provide data support for resource utilization of the stems and leaves of Astragalus membranaceus var. mongholicus(SLAM) by analyzing and evaluating the chemical constituents. The crude protein, crude fiber, and soluble saccharide of SLAM were analyzed by Kjeldahl method, filtration method, and UV-Vis spectrophotometry, respectively. The nucleosides, amino acids, flavonoids, and saponins of SLAM were analyzed by ultraperformance liquid chromatography-triple quadrupole mass spectrometry(UPLC-TQ-MS). Combined with principal component analysis(PCA), the quality difference of resource components of SLAM was comprehensively evaluated. The results showed that the average content of crude protein, crude fiber, total polysaccharide, and redu-cing sugar in SLAM was 5.11%, 30.33%, 11.03 mg·g~(-1), and 31.90 mg·g~(-1), respectively. Six nucleosides, 15 amino acids, 22 flavonoids, and one saponin were detected, with an average content of 1.49 mg·g~(-1), 6.00 mg·g~(-1), 1.86 mg·g~(-1), and 35.67 µg·g~(-1), respectively. The content of various types of chemical components in SLAM differed greatly in different harvesting periods and growing years. The results of PCA showed that the quality of SLAM produced in Ningxia was superior. The results can provide references for the utilization of SLAM.

Temperature Change between Neighboring Days Contributes to Years of Life Lost per Death from Respiratory Disease: A Multicounty Analysis in Central China.

BACKGROUND: Many epidemiological studies have recently assessed respiratory mortality attributable to ambient temperatures. However, the associations between temperature change between neighboring days and years of life lost are insufficiently studied. Therefore, we assessed the attributable risk of temperature change between neighboring days on life loss due to respiratory disease. METHODS: We obtained daily mortality and weather data and calculated crude rates of years of life lost for 70 counties in Hunan Province, Central China, from 2013 to 2017. A time-series design with distributed lag nonlinear model and multivariate meta-regression was used to pool the relationships between temperature change between neighboring days and rates of years of life lost. Then, we calculated the temperature change between neighboring days related to average life loss per death from respiratory disease. RESULTS: The total respiratory disease death was 173,252 during the study period. The association between temperature change and years of life lost rates showed a w-shape. The life loss per death attributable to temperature change between neighboring days was 2.29 (95% CI: 0.46-4.11) years, out of which 1.16 (95% CI: 0.31-2.01) years were attributable to moderately high-temperature change between neighboring days, and 0.99 (95% CI: 0.19-1.79) years were attributable to moderately low-temperature change between neighboring days. The temperature change between neighboring days related to life loss per respiratory disease death for females (2.58 years, 95% CI: 0.22-4.93) and the younger group (2.97 years, 95% CI: -1.51-7.44) was higher than that for males (2.21 years, 95% CI: 0.26-4.16) and the elderly group (1.96 years, 95% CI: 0.85-3.08). An average of 1.79 (95% CI: 0.18-3.41) life loss per respiratory disease death was related to non-optimal ambient temperature. CONCLUSIONS: The results indicated that more attention should be given to temperature change, and more public health policies should be implemented to protect public health.

Impact of ambient temperature on life loss per death from cardiovascular diseases: a multicenter study in central China.

BACKGROUND: In the context of global climate change, studies have focused on the ambient temperature and mortality of cardiovascular diseases (CVDs). However, little is known about the effect of ambient temperature on year of life lost (YLL), especially the life loss per death caused by ambient temperature. In this study, we aimed to assess the relationship between ambient temperature and life loss and estimate the impact of ambient temperature on life loss per death. METHODS: We collected daily time series of mortality and meteorological data from 70 locations in Hunan province, central China, in periods ranging from Jan. 1, 2013, to Dec. 31, 2017. Crude rates of YLL were calculated per 100,000 people per year (YLL/100,000 population) for each location. A distributed lag nonlinear model and multivariate meta-regression were used to estimate the associations between ambient temperature and YLL rates. Then, the average life loss per death attributable to ambient temperature was calculated. RESULTS: There were 711,484 CVD deaths recorded within the study period. The exposure-response curve between ambient temperature and YLL rates was inverted J or U-shaped. Relative to the minimum YLL rate temperature, the life loss risk of extreme cold temperature lasted for 10 to 12 days, whereas the risk of extreme hot temperature appeared immediately and lasted for 3 days. On average, the life loss per death attributable to non-optimum ambient temperatures was 1.89 (95% CI, 1.21-2.56) years. Life loss was mainly caused by cold temperature (1.13, 95% CI, 0.89­1.37), particularly moderate cold (1.00, 95% CI, 0.78­1.23). For demographic characteristics, the mean life loss per death was relatively higher for males (2.07, 95% CI, 1.44­2.68) and younger populations (3.72, 95% CI, 2.06­5.46) than for females (1.88, 95% CI, 1.21-2.57) and elderly people (1.69, 95% CI, 1.28-2.10), respectively. CONCLUSIONS: We found that both cold and hot temperatures significantly aggravated premature death from CVDs. Our results indicated that the whole range of effects of ambient temperature on CVDs should be given attention.

MicroRNA-30b functions as a tumour suppressor in human colorectal cancer by targeting KRAS, PIK3CD and BCL2.

Colorectal cancer (CRC) is the third most common cancer in the USA. MicroRNAs play important roles in the pathogenesis of CRC. In this study, we investigated the role of miR-30b in CRC and found that its expression was significantly lower in CRC tissues than that in normal tissues. We showed that a low expression level of miR-30b was closely related to poor differentiation, advanced TNM stage and poor prognosis of CRC. Further experiments showed that over-expression of miR-30b suppressed CRC cell proliferation in vitro and tumour growth in vivo. Specifically, miR-30b promoted G1 arrest and induced apoptosis. Moreover, KRAS, PIK3CD and BCL2 were identified as direct and functional targets of miR-30b. MiR-30b directly targeted the 3'-untranslated regions of their mRNAs and repressed their expression. This study revealed functional and mechanistic links between miRNA-30b and oncogene KRAS, PIK3CD and BCL2 in the pathogenesis of CRC. MiR-30b not only plays important roles in the regulation of cell proliferation and tumour growth in CRC, but is also a potential prognostic marker or therapeutic target for CRC. Restoration of miR-30b expression may represent a promising therapeutic approach for targeting malignant CRC.

microRNA-224 promotes cell proliferation and tumor growth in human colorectal cancer by repressing PHLPP1 and PHLPP2.

PURPOSE: To investigate the clinicopathologic significance, role, and mechanism of action of microRNA-224 (miR-224) in colorectal cancer. EXPERIMENTAL DESIGN: Real-time PCR was used to quantify miR-224 expression. The association of miR-224 with the clinicopathologic features and survival was evaluated in 110 colorectal cancer patients. The role of miR-224 in colorectal cancer was investigated using in vitro and in vivo assays. Luciferase reporter assays were conducted to confirm target gene associations. RESULTS: miR-224 was overexpressed in colorectal cancer. High-level expression of miR-224 was significantly associated with an aggressive phenotype and poor prognosis. Overexpression of miR-224 promoted colorectal cancer cell proliferation in vitro and tumor growth in vivo. Specifically, miR-224 accelerated the G1-S phase transition through activation of AKT/FOXO3a signaling, downregulation of p21Cip1 and p27Kip1, and upregulation of cyclin D1. Moreover, both PH domain leucine-rich-repeats protein phosphatase 1 (PHLPP1) and PHLPP2, antagonists of PI3K/AKT signaling, were confirmed as bona fide targets of miR-224. miR-224 directly targeted the 3'-untranslated regions of the PHLPP1 and PHLPP2 mRNAs and repressed their expression. CONCLUSION: This study reveals functional and mechanistic links between miRNA-224 and the tumor suppressors PHLPP1 and PHLPP2 in the pathogenesis of colorectal cancer. miR-224 not only plays important roles in the regulation of cell proliferation and tumor growth in colorectal cancer, but also has potential as a prognostic marker or therapeutic target for colorectal cancer.

[Mechanism of recombinant adenovirus-mediated mutations of hypoxia inducible factor 1alpha in modulation of cell apoptosis].

OBJECTIVE: To investigate the mechanism by which recombinant adenovirus (Ad)-mediated mutations of hypoxia inducible factor 1alpha (Ad-HIF-1alpha-Ala564-Ala803) regulates cell apoptosis. METHODS: LoVo cells were infected with recombinant Ad-HIF-1alpha-Ala564-Ala803 and control virus Ad-lacZ under normoxia condition. Real-time PCR was used to detect HIF-1alpha and p21WAF1/CIP1 mRNA expressions at different time points. Western blotting was employed to verify HIF-1alpha and p21WAF1/CIP1 protein expression. Hoechst 33342 flourescein staining was performed to observe the ratio of apoptotic LoVo cells. RESULTS: The expression levels of HIF-1alpha mRNA and protein increased after infection with Ad-HIF-1alpha- Ala564-Ala803, accompanied by an increase in p21WAF1/CIP1 mRNA and protein expressions. The apoptotic ratio was significantly higher in LoVo cells infected with recombinant Ad-HIF-1alpha-Ala564-Ala803 (16.2%) than in the control cells (5.5%, P=0.00). CONCLUSION: HIF-1alpha may induce cell cycle arrest by up-regulating p21WAF1/CIP1 expressions to promote LoVo cell apoptosis.

[Construction and identification of adenovirus vector for double-mutant human hypoxia-inducible factor-1alpha gene].

OBJECTIVE: To construct an adenovirus vector containing the double-mutant hypoxia-inducible factor-1alpha (HIF-1alpha) gene for exploring the therapeutic angiogenesis for coronary heart disease. METHODS: Human double-mutant HIF-1alpha cDNA was obtained from PCR of pShuttle-2-HIF-1alpha containing the mutant HIF-1alpha gene (564). The recombinant adenoviral plasmid containing mutant HIF-1alpha cDNA was constructed by ligation of recombinant pShuttle2 containing double-mutant HIF-1alpha cDNA and Adeno-X viral DNA, followed by its identification and transfection into adenoviral packaging cells HEK293 via lipofectamine 2000. RESULT AND CONCLUSION: The recombinant pAdeno-HIF-1alpha was correctly constructed and verified by restriction endonuclease and DNA sequencing analyseis. This recombinant adenovirus containing the double-mutant HIF-1alpha gene may facilitate further investigation of mutant HIF-1alphagene therapy for coronary heart disease.