Seismic Performance of Steel-Reinforced Concrete Columns with Q690 High-Strength Steel.

In this paper, based on the low-cycle loading tests of 11 steel-reinforced concrete (SRC) frame columns with built-in Q690 steel and 5 SRC frame columns with built-in Q235 steel, a systematic study on their seismic performance was carried out. The design parameters of the specimens were the steel strength, axial compression ratio, shear span ratio, steel content, and stirrup ratio. The failure modes, stress characteristics, hysteresis curve, skeleton curve, displacement ductility performance, energy dissipation capacity, and other main seismic indicators of the specimens with different parameters were analyzed, and the corresponding relationship between the displacement ductility performance of the specimen and the energy dissipation capacity and design parameters was obtained. The results show that the load-displacement curve of the specimens is relatively full, the descending section is gentle, and various seismic performance indicators are relatively excellent, reflecting good seismic performance. Equipped with high-strength steel SRC frame columns, they can better bear the horizontal load, the displacement ductility performance is improved, and the energy dissipation capacity is slightly lower than that of ordinary-strength steel SRC frame columns. The increase in the shear span ratio, steel content, and stirrup ratio of the specimens helps to improve their seismic performance, whereas an increase in the axial compression ratio makes their seismic performance worse.

Angiography in pediatric patients: Measurement and estimation of femoral vessel diameter.

The diameter of femoral vessels was angiographically explored in pediatric patients with congenital heart disease (CHD) and compared with anthropometric and demographic indexes.A total of 153 pediatric patients younger than 3 years old were recruited. The sex, age, weight, and height of patients were recorded daily, and the body surface area (BSA) was calculated with the Mosteller formula.The values of mean left-right diameters were 3.13 (0.32) mm for the femoral artery (FA) and 5.14 (0.68) mm for the femoral vein (FV). The FA diameter (FA-Dm) and FV diameter (FV-Dm) were clearly related (R = 0.84, P < .001), and the FA-Dm/FV-Dm ratio ranged from 0.61 to 0.622. The diameters of femoral vessels were significantly correlated with age, height, weight and BSA (R = 0.63 to 0.73, P < .001). The FA-Dm and FV-Dm were most closely associated with the height of patients (FA-Dm: R = 0.73, P < .001; FV-Dm: R = 0.69, P < .001).The FV-Dm and FA-Dm were consistent with the weight, height, age and BSA in the surveyed pediatric patients. The FA-Dm and FV-Dm were closely associated with the height of pediatric patients. Furthermore, the FA-Dm/FV-Dm ratio was stable in these patients. Such estimations could help clinicians select the appropriate diameter of cannulation needles and catheters for interventional therapy pediatric patients with CHD.

Adding nutrients to the biocontrol strain JK-SH007 promotes biofilm formation and improves resistance to stress.

Burkholderia pyrrocinia JK-SH007 is an important biocontrol strain for the prevention and treatment of poplar canker disease. Its powerful biocontrol function is inseparable from its successful colonization of poplar trees. Bacterial biofilms can ensure the long-term colonization of a host. To explore the mechanism of action of biofilms in the biocontrol process, we manipulated various exogenous factors to explore the morphology of the JK-SH007 biofilm in vitro. The addition of glycerol and MgSO4 to TSB medium stimulated biofilm production, increased the resistance of JK-SH007 to disease, enhanced the survival of JK-SH007 in nutrient-poor environments and maintained the antagonistic ability of JK-SH007 against the poplar canker pathogen. Therefore, we constructed and optimized a biofilm-forming system to produce a large number of stable JK-SH007 biofilms. The optimized system showed that the optimal incubation time for JK-SH007 biofilm formation was 14 h, the optimal temperature of the static culture was 25 °C, and the optimal pH was 5. The optimal medium for biofilm formation was TSB medium, 1% glycerol and 50 mM MgSO4. RT-qPCR experiments showed that an increase in the expression of the suhB gene promoted JK-SH007 biofilm formation, while an increase in the expression level of the ropN gene inhibited JK-SH007 biofilm formation. The possible mechanism by which JK-SH007 was inhibited by biofilm formation under natural culture was revealed. These results indicate the importance of adding nutrients to JK-SH007 biocides produced on a commercial scale. This is the first report of JK-SH007 producing a long-lasting biofilm that guarantees antagonism.

Indole-3-Acetic Acid in Burkholderia pyrrocinia JK-SH007: Enzymatic Identification of the Indole-3-Acetamide Synthesis Pathway.

Burkholderia pyrrocinia JK-SH007 is a plant growth-promoting bacteria (PGPB), that can promote the growth of poplar and other trees, and, production of the plant hormone indole-3-acetic acid (IAA) is one of the reasons for this effect. Therefore, the aims of this study were to evaluate the effect of the external environment on the synthesis of IAA by B. pyrrocinia JK-SH007 and to perform a functional analysis of its IAA synthesis pathway. In this study, IAA and its synthetic intermediates indole-3-acetamide (IAM), indole-3-pyruvic acid (IPyA), tryptamine (TAM), and indole-3-acetonitrile (IAN) were detected in B. pyrrocinia JK-SH007 fermentation broth by high-performance liquid chromatography and tandem mass spectrometry (HPLC-MS/MS), and these indolic compounds were also found in the cell-free extraction of B. pyrrocinia JK-SH007, but the genomic analysis of B. pyrrocinia JK-SH007 indicated that IAA biosynthesis was mainly through the IAM and TAM pathways. The effects of L-tryptophan (L-Trp), temperature and pH on the synthesis of IAA were investigated, and the results showed that L-Trp exerted a significant effect on IAA synthesis and that 37°C and pH 7 were the optimal conditions IAA production by B. pyrrocinia JK-SH007. In addition, the protein expression of tryptophan 2-monooxygenase and indoleacetamide hydrolase, which are the key enzymes of the indole acetamide-mediated IAA synthesis pathway, was analyzed, and their activity was verified by substrate feeding experiments. The results revealed the existence of an IAA synthesis pathway mediated by IAM and indicated that this pathway plays a role in B. pyrrocinia JK-SH007. This study lays the foundation for further exploration of the specific pathway and mechanism of IAA synthesis in B. pyrrocinia JK-SH007.