Second-Harmonic Generation and Spectrum Modulation by Active Nonlinear Metamaterial

The nonlinear properties of a metamaterial sample composed of double-layer metallic patterns and voltage controllable diodes are experimentally investigated. Second harmonics and spectrum modulations are clearly observed in a wide band of microwave frequencies, showing that this kind of metamaterial is not only tunable by low DC bias voltage, but also behaves strong nonlinear property under a small power incidence. These properties are difficult to be found in normal, naturally occurring materials.Comment: 14 pages, 4 figure

Mechanisms and Application for Hydraulic Pulsed Cavitating Jet Generator

To improve the rate of penetration (ROP) further, based on analysis of the jet modulating mechanism, a new drilling tool is designed which couples the advantages of both pulsed jet and cavitating jet. When drilling fluid flows through the tool in drilling process, the fluid is modulated to pulsed and cavitating jet by impellers and in self-resonant chamber. Thus, pulsed cavitating jet is formed at the outlet of the bit nozzle. Because of jet pulsation, cavitating erosion and local negative pressure effect, bottom cuttings cleaning efficiency is enhanced and the ROP is improved. The hydraulic pulsed cavitating jet generator has been applied in 8 oil fields and more than 100 wells in China. The results indicated that the maximum density of test drilling fluid was 1.70 g/cm3, the maximum test well depth was 6,162 m. The generator could work over 230 h, and the maximum operation time was above 520 h. As the result, the average ROP had been increased by 10.1% to 104.4%. The generator has the characteristics of simple structure and long operation time, and has a well adaptability to the existing drilling equipments, technological parameters, which provides a safe and efficient new drilling technology for deep well

PALMD regulates aortic valve calcification via altered glycolysis and NF-κB-mediated inflammation

Recent genome-wide association and transcriptome-wide association studies have identified an association between the PALMD locus, encoding palmdelphin, a protein involved in myoblast differentiation, and calcific aortic valve disease (CAVD). Nevertheless, the function and underlying mechanisms of PALMD in CAVD remain unclear. We herein investigated whether and how PALMD affects the pathogenesis of CAVD using clinical samples from CAVD patients and a human valve interstitial cell (hVIC) in vitro calcification model. We showed that PALMD was upregulated in calcified regions of human aortic valves and calcified hVICs. Furthermore, silencing of PALMD reduced hVIC in vitro calcification, osteogenic differentiation, and apoptosis, whereas overexpression of PALMD had the opposite effect. RNA-Seq of PALMD-depleted hVICs revealed that silencing of PALMD reduced glycolysis and nuclear factor-κB (NF-κB)–mediated inflammation in hVICs and attenuated tumor necrosis factor α–induced monocyte adhesion to hVICs. Having established the role of PALMD in hVIC glycolysis, we examined whether glycolysis itself could regulate hVIC osteogenic differentiation and inflammation. Intriguingly, the inhibition of PFKFB3-mediated glycolysis significantly attenuated osteogenic differentiation and inflammation of hVICs. However, silencing of PFKFB3 inhibited PALMD-induced hVIC inflammation, but not osteogenic differentiation. Finally, we showed that the overexpression of PALMD enhanced hVIC osteogenic differentiation and inflammation, as opposed to glycolysis, through the activation of NF-κB. The present study demonstrates that the genome-wide association– and transcriptome-wide association–identified CAVD risk gene PALMD may promote CAVD development through regulation of glycolysis and NF-κB–mediated inflammation. We propose that targeting PALMD-mediated glycolysis may represent a novel therapeutic strategy for treating CAVD

PFKFB3-driven vascular smooth muscle cell glycolysis promotes vascular calcification via the altered FoxO3 and lactate production

A link between increased glycolysis and vascular calcification has recently been reported, but it remains unclear how increased glycolysis contributes to vascular calcification. We therefore investigated the role of PFKFB3, a critical enzyme of glycolysis, in vascular calcification. We found that PFKFB3 expression was upregulated in calcified mouse VSMCs and arteries. We showed that expression of miR-26a-5p and miR-26b-5p in calcified mouse arteries was significantly decreased, and a negative correlation between Pfkfb3 mRNA expression and miR-26a-5p or miR-26b-5p was seen in these samples. Overexpression of miR-26a/b-5p significantly inhibited PFKFB3 expression in VSMCs. Intriguingly, pharmacological inhibition of PFKFB3 using PFK15 or knockdown of PFKFB3 ameliorated vascular calcification in vD3 -overloaded mice in vivo or attenuated high phosphate (Pi)-induced VSMC calcification in vitro. Consistently, knockdown of PFKFB3 significantly reduced glycolysis and osteogenic transdifferentiation of VSMCs, whereas overexpression of PFKFB3 in VSMCs induced the opposite effects. RNA-seq analysis and subsequent experiments revealed that silencing of PFKFB3 inhibited FoxO3 expression in VSMCs. Silencing of FoxO3 phenocopied the effects of PFKFB3 depletion on Ocn and Opg expression but not Alpl in VSMCs. Pyruvate or lactate supplementation, the product of glycolysis, reversed the PFKFB3 depletion-mediated effects on ALP activity and OPG protein expression in VSMCs. Our results reveal that blockade of PFKFB3-mediated glycolysis inhibits vascular calcification in vitro and in vivo. Mechanistically, we show that FoxO3 and lactate production are involved in PFKFB3-driven osteogenic transdifferentiation of VSMCs. PFKFB3 may be a promising therapeutic target for the treatment of vascular calcification.</p

Hypercapsule is the cornerstone of Klebsiella pneumoniae in inducing pyogenic liver abscess

PurposeTo investigate the mechanisms of Klebsiella pneumoniae-induced pyogenic liver abscess (PLA).MethodsForty-three K. pneumoniae strains from PLAs and 436 from non-PLAs were collected. Their differences were compared for virulence genes and factors, sequence types, and serotypes. Virulence genes wzi, wzy-K1, and wzi+wzy-K1 were deleted in K. pneumoniae NTUH-K2044. Various analyses, such as transmission electron microscopy, neutrophil killing tests, and mouse lethality tests, were used to confirm the consequent changes.ResultsDifferences were found between K. pneumoniae strains from PLA and non-PLA samples for virulence genes and factors, including metabolism genes (allS and peg-344), capsular polysaccharide (CPS)-synthesis channel gene (wzy-K1), CPS-regulating genes (p-rmpA, p-rmpA2, and c-rmpA), and siderophore genes (iucA and iroN). When wzy-K1 was positive, the difference between PLA and non-PLA samples was only observed with c-rmpA. Δwzi, Δwzy-K1, and ΔwziΔwzy-K1 strains reverted to hypovirulence. In the Kupffer cell stimulation assay, interleukin (IL)-6, IL-12, IL-10, and transforming growth factor-β secretions were found to be equivalent in NTUH-K2044, Δwzi, Δwzy-K1, and ΔwziΔwzy-K1 groups. Lower IL-1β and higher tumor necrosis factor-α secretions were observed for Δwzi, Δwzy-K1, and ΔwziΔwzy-K1.ConclusionsHypercapsule production is the cornerstone of hypervirulence, regardless of exopolysaccharides. K1 K. pneumoniae-induced PLA may decrease core inflammatory cytokines rather than increase anti-inflammatory cytokines. Exopolysaccharides could also attenuate the inflammatory response to aid in the immune escape of K. pneumoniae

An atlas of DNA methylomes in porcine adipose and muscle tissues

It is evident that epigenetic factors, especially DNA methylation, have essential roles in obesity development. Here, using pig as a model, we investigate the systematic association between DNA methylation and obesity. We sample eight variant adipose and two distinct skeletal muscle tissues from three pig breeds living within comparable environments but displaying distinct fat level. We generate 1,381 Gb of sequence data from 180 methylated DNA immunoprecipitation libraries, and provide a genome-wide DNA methylation map as well as a gene expression map for adipose and muscle studies. The analysis shows global similarity and difference among breeds, sexes and anatomic locations, and identifies the differentially methylated regions. The differentially methylated regions in promoters are highly associated with obesity development via expression repression of both known obesity-related genes and novel genes. This comprehensive map provides a solid basis for exploring epigenetic mechanisms of adipose deposition and muscle growth

Influence of Piezoelectric Performance on Nonlinear Dynamic Characteristics of MFC Shells

Based on the structures of unmanned aerial vehicle (UAV) wings, nonlinear dynamic analysis of macrofiber composite (MFC) laminated shells is presented in this paper. The effects of piezoelectric properties and aerodynamic forces on the dynamic stability of the MFC laminated shell are studied. Firstly, under the flow condition of ideal incompressible fluid, the thin airfoil theory is employed to calculate the effects of the mean camber line to obtain the circulation distribution of the wings in subsonic air flow. The steady aerodynamic lift on UAV wings is derived by using the Kutta–Joukowski lift theory. Then, considering the geometric nonlinearity and piezoelectric properties of the MFC material, the nonlinear dynamic model of the MFC laminated shell is established with Hamilton’s principles and the Galerkin method. Next, the effects of electric field, external excitation force, and nonlinear parameters on the stability of the system are studied under 1 : 1 internal resonance and the effects of material parameters on the natural frequency of the structure are also analyzed. Furthermore, the influence of the aerodynamic forces and electric field on the nonlinear dynamic responses of MFC laminated shells is discussed by numerical simulation. The results indicate that the electric field and external excitation have great influence on the structural dynamic responses

Characterization of the Dynamic Imbibition Displacement Mechanism in Tight Sandstone Reservoirs Using the NMR Technique

An experimental technique is developed to investigate the dynamic imbibition displacement mechanism in tight sandstone formations of the Yanchang group of the Ordos basin. By combining the dynamic imbibition core flooding experiments and NMR technique, the effects of the injection volume and rate on displacement efficiency are investigated. Moreover, the displacement efficiency of dynamic imbibition is compared with that of static imbibition. This study gains insights into the micromechanisms of dynamic imbibition in tight sandstone formations. It is found that the relative displacement efficiency of dynamic imbibition increases with the increase of injection volume. But the increment amplitude decreases with the increase of injection volume. With the same injection volume, the core displacement efficiency of dynamic imbibition with high permeability is obviously improved. However, the core displacement efficiency decreases rapidly with the increase of injection volume. Optimal injection volumes are recommended for tight sandstone formations with different permeabilities. With the increase of the displacement rate, the core displacement efficiency of dynamic imbibition shows a trend of first rising and then declining. There exists an optimal displacement rate in dynamic imbibition displacement, and the optimal displacement rate almost linearly increases with the increase of core permeability. The static imbibition displacement efficiency increases with the increase of soaking time, but the increment amplitude slows down obviously. The displacement efficiency of static imbibition in small pores is higher than that of dynamic imbibition. The displacement efficiency of dynamic imbibition in large pores or microcracks is significantly higher than that of static imbibition. This study provides theoretical support for the optimization and improvement of the waterflooding recovery process in tight sandstone reservoirs.Peer Reviewe