Analysis of the positive forces exhibiting on the mooring line of composite-type sea cage

According to the commonly used arrangements of gravity sea cages in deep sea farming, 5 composite type working models are designed with modelbased testing by which the forces acting on the mooring line are measured under pure current, pure wave and the combination of both. Meanwhile, the forces acting on the normal mooring line are also analyzed. Based on the test data, a conclusion is made about the characteristics of the mooring line force. In the end, some feasible suggestions are given, which should be adopted for arrangement of sea cages in real farming

Analysis of Strength Characteristics and Energy Dissipation of Improved-Subgrade Soil of High-Speed Railway above Mined-Out Areas

To reveal the effect of sand content on the mechanical performance and energy dissipation of cement improved subgrade soil, using universal testing machine and SHPB test device, unconfined compressive strength (UCS) and impact compression strength under different impact load (0.2, 0.3, 0.4, and 0.5 MPa) were carried out for the cement improved subgrade soil with different sand content (0%, 5%, 10%, 15%, and 20%). Results show that the dynamic and static stress-strain curves of the cement improved soil have similar variation trend. With the increase of the sand content, the UCS and impact compressive strength of the cement improved soil both increase first, then decrease later, showing the form of a quadratic function. The strength growth rate and the dynamic increase factor (DIF) reach the maximum values when the sand content is 10%, which is 64.7% and 18.6% larger than that of ordinary improved subgrade soil, respectively. In addition, when the sand content increases from 0% to 20%, the specific dissipation energy increases first, and decreases later. Mixing 10% natural sand is the optimal proportion to obtain better energy dissipation capacity of the sand-cement-improved soil

High-Temperature sensor based on peanut flat-end reflection structure

A high-temperature sensor based on a peanut flat-end reflection structure is demonstrated. The sensor can be simply fabricated by splicing the spherical end-faces of two segments of single-mode fibers and then cleaving one other end as a flat reflect surface. The proposed structure works as a reflected interferometer. When the ambient temperature changes, the resonant dip wavelength of the interferometer will shift due to the linear expansion or contraction and the thermo-optic effect. As a result, the temperature measurement can be achieved by monitoring the resonant dip wavelength of the interferometer. Experimental results show that the proposed sensor probe based on the peanut flat-end reflection structure works well and it can measure the temperature range from 100 °C to 900 °C with the sensitivity of 0.098 nm/ °C with R²  =  0.988. When temperature ranges from 400 °C to 900 °C, the sensitivity of 0.11 nm/ °C can be achieved with R² = 0.9995. Due to its compact and simple configuration, the proposed sensor is a good high temperature sensor probe.This work is supported by the Natural Science Foundation of Zhejiang Province China under Grant No.LY17F050010

Molecular cloning and characterization of an actindepolymerizing factor gene in Hevea brasiliensis

Actin-depolymerizing factor (ADF) plays important roles in regulating actin dynamics by maintaining the optimum equilibrium between unpolymerized actin molecules and assembled actin filaments in different cellular processes. In this study, the first ADF gene in Hevea brasiliensis designated as HbADF, was isolated. The HbADF contained an open reading frame (ORF) encoding 139 amino acids. The deduced HbADF showed high identities to plants ADF proteins. Besides a conserved ADF domain, HbADF also contained putative actin and specific F-actin binding sites, phosphorylation site and possible CAM (calmodulin) combining region. The phylogenetic analysis indicated that HbADF was clustered in the subclass I. Being consistent with  phylogenetic result, the expression of HbADF was constitutive. The HbADF transcripts were upregulated by ethephon and wounding treatments; whereas, HbADF was firstly induced, and then gradually downregulated by jasmonic acid. The expression profiles and characterizations of HbADF suggested that HbADF might be  associated with latex regeneration and flow in H. brasiliensis.Key words: Actin cytoskeleton, actin-depolymerizing factor, expression analysis, Hevea brasiliensis, semiquantitative reverse-transcription polymerase chain reaction

Skewed Pressure Characteristics of Equivalent Load in Double-Arch Tunnel

It is of great importance to reasonably estimate the surrounding rock load of a double-arch tunnel for the design, construction and stability evaluation of the tunnel. Currently, the basic theory on surrounding rock pressure of double-arch tunnels is insufficient for properly making the design and calculations. Generally, simplified calculations based on experience are used, such as the calculation method of Protodyakonov\u27s theory, the building code method and others. Considering the fact that the surrounding rock pressure of double-arch tunnels has skewed distribution characteristics, a computational model of a double-arch tunnel was built using data from an actual excavation of a highway tunnel. Taking some factors into consideration, such as different stress states, different construction methods and different sizes of double-arch tunnels, the pressure evolution of the surrounding rock was analyzed during step-by-step excavation of the double-arch tunnel. The results showed that in each condition the surrounding rock pressure of the double-arch tunnel displayed skewed distribution characteristics. The skewed distribution of the surrounding rock pressure varied with changes in stress state, construction sequence and excavation size. The skewed pressure of the double-arch tunnel was converted to equivalent load. The conversion method and distribution characteristics of the equivalent load are specified. They have important theoretical significance and practical value for similar engineering practices

Identification and characterization of genes associated with tapping panel dryness from Hevea brasiliensis latex using suppression subtractive hybridization

<p>Abstract</p> <p>Background</p> <p>Tapping panel dryness (TPD) is one of the most serious threats to natural rubber production. Although a great deal of effort has been made to study TPD in rubber tree, the molecular mechanisms underlying TPD remain poorly understood. Identification and systematical analyses of the genes associated with TPD are the prerequisites for elucidating the molecular mechanisms involved in TPD. The present study is undertaken to generate information about the genes related to TPD in rubber tree.</p> <p>Results</p> <p>To identify the genes related to TPD in rubber tree, forward and reverse cDNA libraries from the latex of healthy and TPD trees were constructed using suppression subtractive hybridization (SSH) method. Among the 1106 clones obtained from the two cDNA libraries, 822 clones showed differential expression in two libraries by reverse Northern blot analyses. Sequence analyses indicated that the 822 clones represented 237 unique genes; and most of them have not been reported to be associated with TPD in rubber tree. The expression patterns of 20 differentially expressed genes were further investigated to validate the SSH data by reverse transcription PCR (RT-PCR) and real-time PCR analysis. According to the Gene Ontology convention, 237 unique genes were classified into 10 functional groups, such as stress/defense response, protein metabolism, transcription and post-transcription, rubber biosynthesis, etc. Among the genes with known function, the genes preferentially expressed were associated with stress/defense response in the reverse library, whereas metabolism and energy in the forward one.</p> <p>Conclusions</p> <p>The genes associated with TPD were identified by SSH method in this research. Systematic analyses of the genes related to TPD suggest that the production and scavenging of reactive oxygen species (ROS), ubiquitin proteasome pathway, programmed cell death and rubber biosynthesis might play important roles in TPD. Therefore, our results not only enrich information about the genes related to TPD, but also provide new insights into understanding the TPD process in rubber tree.</p

Excisanin A suppresses proliferation by inhibiting hypoxiainducible factor-1α expression in human hepatocellular carcinoma cells

Purpose: To investigate the effect of excisanin A on human hepatocellular carcinoma cells as well as to elucidate its mechanism of action. Methods: Molecular docking was used to determine the binding characteristics of excisanin A to HIF-1α protein. The transcriptional activation and viability of excisanin A were assessed using Luciferase reporter and MTT assay. The HIF-1α protein in the nucleus was assayed using western blot and immunofluorescence. HIF-1α and VEGF mRNA levels were evaluated using reverse-transcription polymerase chain reaction (RT-PCR). Cell proliferation was determined by flow cytometry, as well as by EdU and clonogenic assays. In vivo tumor growth was assessed in a murine xenograft model of SKHep1 cells. Results: Excisanin A inhibited HIF-1α transcriptional activation, as well as HIF-1α protein synthesis (p &lt; 0.001). Excisanin A also reduced VEGF protein and mRNA expressions (p &lt; 0.001). In addition, the compound inhibited the proliferation of hepatocellular carcinoma cells. and tumor growth in the xenograft tumor model. Conclusion: Excisanin A is a potent HIF-1α inhibitor, supporting its potential development for human hepatoma therapy. Keywords: Excisanin A, HIF-1α, Protein synthesis, Hepatoma therap

Association of perceived stress and sleep quality among medical students: the mediating role of anxiety and depression symptoms during COVID-19

COVID-19 has intensified the influence on medical students by changing the lifestyle, online study and clinical practice which bring out series of stress, sleep disturbance and mental health problems. This cross-sectional study aim to explore the association between perceived stress and sleep quality among medical students and investigated whether anxiety and depression mediated this association during pandemic. A total of 1,021 medical students in two universities who were from Guangdong Province, China participated this study and from January to September 2020 through the online question are, with 28.80% reporting sleep disturbances. The medical students were finished various self-reported questionnaires, including the Perceived Stress Scale-10, Pittsburgh Sleep Quality Index, Generalized Anxiety Disorder-7 Scale, and Patient Health Questionnaire-9, the study found positive correlations among sleep quality, perceived stress, anxiety, and depression. The data was analyzed with The Amos 26.0 system. Result demonstrated that perceived stress was associated with poor sleep quality. Anxiety and depression partially mediated the association between perceived stress and poor sleep quality, explaining 73.08% of the association. This study’s structural equation model offers a useful framework for assessing mechanisms mediating associations between perceived stress and sleep quality. The findings emphases the importance of addressing psychological factors in high-pressure situations, which can exacerbate sleep disturbances among medical students. It is important to screen the level of stress, mental health problems and investigate the risk factors of sleep quality among medical students during emergency public health events