Putative Circulating MicroRNAs Are Able to Identify Patients with Mitral Valve Prolapse and Severe Regurgitation

Mitral valve prolapse (MVP) associated with severe mitral regurgitation is a debilitating disease with no pharmacological therapies available. MicroRNAs (miRNA) represent an emerging class of circulating biomarkers that have never been evaluated in MVP human plasma. Our aim was to identify a possible miRNA signature that is able to discriminate MVP patients from healthy subjects (CTRL) and to shed light on the putative altered molecular pathways in MVP. We evaluated a plasma miRNA profile using Human MicroRNA Card A followed by real-time PCR validations. In addition, to assess the discriminative power of selected miRNAs, we implemented a machine learning analysis. MiRNA profiling and validations revealed that miR-140-3p, 150-5p, 210-3p, 451a, and 487a-3p were significantly upregulated in MVP, while miR-223-3p, 323a-3p, 340-5p, and 361-5p were significantly downregulated in MVP compared to CTRL (p ≤ 0.01). Functional analysis identified several biological processes possible linked to MVP. In addition, machine learning analysis correctly classified MVP patients from CTRL with high accuracy (0.93) and an area under the receiving operator characteristic curve (AUC) of 0.97. To the best of our knowledge, this is the first study performed on human plasma, showing a strong association between miRNAs and MVP. Thus, a circulating molecular signature could be used as a first-line, fast, and cheap screening tool for MVP identification.     

Optimisation of the spark plasma sintering process for high volume fraction SiCp/Al composites by orthogonal experimental design

Based on orthogonal experimental design (OED), the effects of the sintering pressure, sintering temperature and holding time on the mechanical properties of 50 vol% silicon carbide particle (SiCp)/2024Al composites prepared by spark plasma sintering (SPS) were investigated. The sintering pressure had the greatest effect on the density and bending strength of the material among these three factors, followed by sintering temperature and holding time. The optimised process conditions for producing the 50 vol% SiCp/2024Al were sintering at 550 °C for 5 min under 40 MPa, which resulted in a composite material with a density of 99.7% and good interface bonding with a comparatively high bending strength of 766.65 MPa. This work provides a promising method to produce high volume fraction composites that can meet high strength requirements.     

Turbulent boundary layer control with a spanwise array of DBD plasma actuators

The turbulent boundary layer control on NACA 0012 airfoil with Mach number ranging from 0.3 to 0.5 by a spanwise array of dielectric barrier discharge(DBD)plasma actuators by hot-film sensor technology is investigated.Due to temperature change mainly caused through heat produced along with plasma will lead to measurement error of shear stress measured by hot-film sensor,the correction method that takes account of the change measured by another sensor is used and works well.In order to achieve the value of shear stress change,we combine computational fluid dynamics computation with experiment to calibrate the hot-film sensor.To test the stability of the hot-film sensor,seven repeated measurements of shear stress at Ma = 0.3 are conducted and show that confidence interval of hot-film sensor measurement is from-0.18 to 0.18 Pa and the root mean square is 0.11 Pa giving a relative error 0.5％over all Mach numbers in this experiment.The research on the turbulent boundary layer control with DBD plasma actuators demonstrates that the control makes shear stress increase by about 6％over the three Mach numbers,which is thought to be reliable through comparing it with the relative error 0.5％,and the value is hardly affected by burst frequency and excitation voltage.     

Modification of exposure conditions by the magnetic field configuration in helicon antenna-excited helium plasma

Modification of exposure conditions downstream in the diffusion chamber has been performed in helicon antenna-excited helium plasma by adjusting the magnetic field(intensity and geometry).In the inductively coupled mode(H mode), a reduction in ion and heat fluxes is found with increasing magnetic field intensity, which is further explained by the more highly magnetized ions off-axis around the last magnetic field lines(LMFL). However, in helicon wave mode(W mode), the increase in magnetic field intensity can dramatically increase the ion and heat fluxes.Moreover, the effect of LMFL geometry on exposure conditions is investigated. In H mode with contracting LMFL, off-axis peaks of both plasma density and electron temperature profiles shift radially inwards, bringing about a beam with better radial uniformity and higher ion and heat fluxes. In W mode, although higher ion and heat fluxes can be achieved with suppressed plasma cross-field diffusion under converging LMFL, the poor radial uniformity and a small beam diameter will limit the size of samples suitable for plasma irradiation experiments.     

Spark plasma sintering of B4C and B4C-TiB2 composites: Deformation and failure mechanisms under quasistatic and dynamic loading

Spark plasma sintering (SPS) was employed to consolidate powder specimens consisting of B₄C and various B₄C-TiB₂ compositions. SPS allowed for consolidation of pure B₄C, B₄C-13 vol.%TiB₂, and B₄C-23 vol.%TiB₂ composites achieving ≥99 % theoretical density without sintering additives, residual phases (e.g., graphite), and excessive grain growth due to long sintering times. Electron and x-ray microscopies determined homogeneous microstructures along with excellent distribution of TiB₂ phase in both small and larger-scaled composites. An optimized B₄C-23 vol.%TiB₂ composite with a targeted low density of ～3.0 g/cm³ exhibited 30–35 % increased hardness, fracture toughness, and flexural bend strength compared to several commercial armor-grade ceramics, with the flexural strength being strain rate insensitive under quasistatic and dynamic loading. Mechanistic studies determined that the improvements are a result of a) no residual graphitic carbon in the composites, b) interfacial microcrack toughening due to thermal expansion coefficient differences placing the B₄C matrix in compression and TiB₂ phase in tension, and c) TiB₂ phase aids in crack deflection thereby increasing the amount of intergranular fracture. Collectively, the addition of TiB₂ serves as a toughening and strengthening phase, and scaling of SPS samples show promise for the manufacture of ceramic composites for body armor.     

Effects of hydrogen plasma treatment on the physical and chemical properties of tin oxide thin films for ambipolar thin-film transistor applications

In this study, we investigated the physical and chemical properties of H₂ plasma-treated tin oxide (SnO_X) thin films, followed by their applications in ambipolar thin-film transistors (TFTs). Finely controlled H₂ implantation was carried out using a reactive-ion-etching system at a radio frequency power of 30 W and under various exposure times. H₂ plasma treatments induced changes in the chemical structures and surface morphologies of the SnO_X thin films, including a partial phase transformation of Sn and SnO to SnO₂. The defects originating from oxygen vacancies (O_Vacs) in the SnO_X thin films were passivated by H via the formation of Sn–H bonds, which decreased the density of subgap states in the SnO_X thin films. The H₂ plasma-treated SnO_X TFTs showed considerably improved ambipolarity and electrical performance. Complementary metal–oxide–semiconductor (CMOS) logic inverters comprising H₂-plasma-treated ambipolar SnO_X TFTs exhibited a maximum gain of 34.5 V/V at a supply voltage of 10 V. The results of this study present the meaningful investigation of H₂ plasma-treated ambipolar SnO_X TFTs that can be used to fabricate CMOS circuits for various applications.     

Microstructure and mechanical properties of α/β-Si3N4 composite ceramics with novel ternary additives prepared via spark plasma sintering

In this study, α/β-Si₃N₄ composite ceramics with high hardness and toughness were fabricated by adopting two different novel ternary additives, ZrN–AlN–Al₂O₃/Y₂O₃, and spark plasma sintering at 1550 °C under 40 MPa. The phase composition, microstructure, grain distribution, crack propagation process and mechanical properties of sintered bulk were investigated. Results demonstrated that the sintered α/β-Si₃N₄ composite ceramics with ZrN–AlN–Al₂O₃ contained the most α phase, which resulted in a maximum Vickers hardness of 18.41 ± 0.31 GPa. In the α/β-Si₃N₄ composite ceramics with ZrN–AlN–Y₂O₃ additives, Zr₃AlN MAX-phase and ZrO phase were found and their formation mechanisms were explained. The fracture appearance presented coarser elongated β-Si₃N₄ grains and denser microstructure when 20 wt% TiC particles were mixed into Si₃N₄ matrix, meanwhile, exhibited maximum mean grain diameter of 0.98 ± 0.24 μm. As a result, the compact α/β-Si₃N₄ composite ceramics containing ZrN–AlN–Y₂O₃ additives and TiC particles displayed the optimal bending strength and fracture toughness of 822.63 ± 28.75 MPa and 8.53 ± 0.21 MPa?m^1/2, respectively. Moreover, the synergistic toughening of rod-like β-Si₃N₄ grains and TiC reinforced particles revealed the beneficial effect on the enhanced fracture toughness of Si₃N₄ ceramic matrix.     

Effects of feed composition,protein denaturation and storage of milk serum protein/lactose powders on lactosylation

During whey powder production, the feed is subjected to several heat treatments which can cause lactosylation of proteins. In this study, lactosylation of whey proteins was evaluated in spray-dried powders before and after storage by varying the native protein fraction as well as the serum protein/lactose ratio in the powders. The lactosylation of native α-lactalbumin and β-lactoglobulin in the powders before storage was not affected to a large extent by the protein denaturation or if the feed had been heat treated in a high or low lactose environment. After storage (relative humidity of 23.5%, 30 °C, 25 days), the kinetic of lactosylation tended to increase with increasing native protein fraction and bulk protein content in the powders. An explanation could be that proteins dissolved in the lactose glassy structure might have a lower reactivity, while proteins present in the protein glassy structure with dissolved lactose may display higher lactosylation reactivity.     

Employing one-step coupling cold plasma and thermal polymerization approach to construct nitrogen defect-rich carbon nitrides toward efficient visible-light-driven hydrogen generation

Construction of structural defects in photocatalysts is a powerful tool for regulating their photocatalytic performance. In this work, we develop a facile one-step coupling cold plasma and thermal polymerization approach to synthesize a series of nitrogen defect-rich graphitic carbon nitrides (C₃N_4-x), which are used for visible-light-driven hydrogen generation from water. The nitrogen defect-induced band structure regulation of C₃N_4-x catalysts can be carried out through controlling the bombardment time and excitation power of generator during the plasma modification process. The defective C₃N_4-x catalysts have the extended visible light absorption and improved separation efficiency of photogenerated charge carriers, which results in the boosted hydrogen generation activity. Particularly, the optimal C₃N_4-x possesses a hydrogen generation rate of 2.46 mmol h^?1 g^?1, which is about 4.5 times higher than the pristine C₃N₄ synthesized by the single thermal polymerization of urea. The cold plasma modification-based one-step synthesis approach guides us for rationally designing defective nanomaterials with excellent catalytic performance.