Search

Background: Three-dimensional (3D) chromatin architecture frequently altered in cancer. However, its changes during the pathogenesis of hepatocellular carcinoma (HCC) remained elusive. Methods: Hi-C and RNA-seq were applied to study the 3D chromatin landscapes and gene expression of HCC and ANHT. Hi-C Pro was used to generate genome-wide raw interaction matrices, which were normalized via iterative correction (ICE). Moreover, the chromosomes were divided into different compartments according to the first principal component (E1). Furthermore, topologically associated domains (TADs) were visualized via WashU Epigenome Browser. Furthermore, differential expression analysis of ANHT and HCC was performed using the DESeq2 R package. Additionally, dysregulated genes associated with 3D genome architecture altered were confirmed using TCGA, qRT-PCR, immunohistochemistry (IHC), etc. Results: First, the intrachromosomal interactions of chr1, chr2, chr5, and chr11 were significantly different, and the interchromosomal interactions of chr4–chr10, chr13–chr21, chr15–chr22, and chr16–chr19 are remarkably different between ANHT and HCC, which resulted in the up-regulation of TP53I3 and ZNF738 and the down-regulation of APOC3 and APOA5 in HCC. Second, 49 compartment regions on 18 chromosomes have significantly switched (A–B or B–A) during HCC tumorigenesis, contributing to up-regulation of RAP2A. Finally, a tumor-specific TAD boundary located on chr5: 6271000–6478000 and enhancer hijacking were identified in HCC tissues, potentially associated with the elevated expression of MED10, whose expression were associated with poor prognosis of HCC patients. Conclusion: This study demonstrates the crucial role of chromosomal structure variation in HCC oncogenesis and potential novel biomarkers of HCC, laying a foundation for cancer precision medicine development. [ABSTRACT FROM AUTHOR]

Objective To isolate, sequence, and identify biological characterization and complete genome sequencing of a virulent Staphylococcus aureus (S. aureus) bacteriophage vB_SauH_IME522. Methods A phage was isolated from sewage of PLA Chinese General Hospital using a clinically isolated S. aureus strain as host bacteria. The double-layer agar plate was used to determine the optimal multiplicity of infection (optimal MOI) and one-step growth curve. Phage morphology was observed by transmission electron microscopy after purification using sucrose gradient separation. Phage DNA was sequenced using the Illumina Miseq sequencing platform. The complete genome sequence was annotated, then comparative genomics and evolutionary analyses were performed. Results A lytic phage of S. aureus was isolated from hospital sewage and named as vB_SauH_IME522. The optimal MOI of the phage was 0.01. One step growth curve showed that its latent period and burst period were 20 and 200 min, respectively. The burst size was about 89 PFU/cell. Electron microscopy displayed the phage having an icosahedral head (70±1) nm and a long contractile tail (135±2) nm. Genome sequencing results showed that the total length of the phage genome was 140 246 bp and the G+C content accounted for 30.2%. The genomic annotation revealed that the phage contained 223 genes coding proteins, 164 putative promoters, 66 terminators, 4 tRNAs, and 7 resistance-related regions. Phylogenetic analysis suggested that the phage was a member of the genus Kayvirus within the subfamily Twortvirinae. Conclusion A lytic phage of S. aureus vB_SauH_IME522 is identified as a new member of the Twortvirinae subfamily, with strong lytic ability and short latent period.

The flow characteristics in reciprocating pump-pipe system are inevitably subject to the interaction effects between pump and pipeline. In this paper, a parametric interaction model of flow characteristics in reciprocating pump-pipe system is presented by considering the coupling effect and leakage characteristics. The analytical solutions of the proposed interaction equations are deduced with the aid of the harmonic balance method. A testing platform of a simplex plunger reciprocating pump-pipe system is employed for validating the proposed model. The experimental tests under different operating conditions are used to compare the pressure pulsations and discharge flow rates from analytical solutions. It is observed that the analytical solutions are in good agreement with the test data and numerical results, and the prediction error is within 13%, thus validating the presented interaction model and analytical solutions. The interaction effects as well as the flow characteristics in reciprocating pump-pipe system are analyzed and discussed using the proposed model. It is found that the opening of flow control valve has remarkable influence on the relationship between flow rate and operating speed of reciprocating pump. The pressure pulsation within a pipe is closely related to and significantly affected by the plunger-to-cylinder clearance and the plunger stroke. [ABSTRACT FROM AUTHOR]

Functionally graded material (FGM) has an important application prospect in aircraft engineering, especially in smart aircraft. The dynamic behavior of FGM has been widely investigated so far but more work is needed for the porous FGM pipes conveying fluid. In this paper, a sensible pore distribution function related with the volume fraction of metal and ceramic is proposed for the dynamic modeling of porous FGM pipes conveying fluid. The maximum porosity and its corresponding position are taken into account in the present mechanical model. The material properties of the porous pipes are temperature dependent and can be affected by pore distribution. The governing equation of the porous FGM pipe is derived and then the exact solution of post buckling is obtained. The nonlinear primary resonance is determined by the multiple scale method. It is shown that the effect of the pore distribution is very significant on the post buckling behavior and nonlinear primary resonance of the porous FGM pipes. The current work is very helpful in understanding the influence of pore distribution on static and dynamic behavior of pores FGM structures in engineering practice. [ABSTRACT FROM AUTHOR]

In this paper, a pendulum-type metamaterial (PTM) is designed with a pendulum bob hinged at the primary mass. Considering the effect of geometric nonlinearity, the nonlinear dynamic equations of PTM unit cell are presented with the aid of the Bloch theorem. The analytical formula of dispersion equation is deduced to discuss the nonlinear internal resonance bandgap using the harmonic balance method. The obtained bandgap of the metamaterial is in good agreement with the numerical simulation result. The nonlinear geometric influence of pendulum on PTM bandwidth is significant. The bandgaps under different internal resonances are substantially different from each other due to the nonlinear effects. The upper boundaries of the frequency bandgap under 1:1/2 and 1:1/3 internal resonance rise nonlinearly to higher than those under linear and 1:1 internal resonance conditions. It shows that the impact of 1:1/2 and 1:1/3 internal resonance on the bandgap could be more obvious as the strong nonlinearity is taken into consideration. [ABSTRACT FROM AUTHOR]

Active vibration control of a smart FG (functionally graded) cylindrical shell conveying fluid in thermal environment is studied theoretically by using a laminated piezoelectric actuator. Velocity feedback control law is implemented to activate the piezoelectric actuator. Considering the electric-thermo-fluid-structure interaction effect, a nonlinear dynamic model of the smart fluid-conveying FG cylindrical shell is developed based on Hamilton’s principle and von-Karman type geometrical nonlinear relationship. The inviscid, incompressible, isentropic and irrotational fluid is coupled into governing equations using the linearized potential theory. The Galerkin’s method is used to obtain the nonlinear governing equations of motion of the coupled system. The multiple time scales approach is applied to solve the resulting governing equations for analysing the nonlinear dynamic characteristics of the coupled system. The influence of fluid flow velocity, feedback control gains of piezoelectric voltage, external excitation and material properties of FGM on the frequency-response curves of system are investigated. The results indicate that the piezoelectric voltage is an effective controlling parameter for vibration control of the system, and the flow velocity can effect significantly the vibration amplitude and nonlinearity of the coupled system.