Plasmin Plays an Essential Role in Amplification of Psoriasiform Skin Inflammation in Mice

BACKGROUND: Although increased levels of plasminogen activators have been found in psoriatic lesions, the role of plasmin converted from plasminogen by plasminogen activators in pathogenesis of psoriasis has not been investigated. METHODOLOGY/PRINCIPAL FINDINGS: Here we examined the contribution of plasmin to amplification of inflammation in patients with psoriasis. We found that plasminogen was diminished, but that the amount and activity of its converted product plasmin were markedly increased in psoriasis. Moreover, annexin II, a receptor for plasmin was dramatically increased in both dermis and epidermis in psoriasis. Plasmin at sites of inflammation was pro-inflammatory, eliciting production of inflammatory factors, including CC chemokine ligand 20 (CCL20) and interleukin-23 (IL-23), that was mediated by the nuclear factor-kappaB (NF-κB) signaling pathway and that had an essential role in the recruitment and activation of pathogenic C-C chemokine receptor type 6 (CCR6)+ T cells. Moreover, intradermal injection of plasmin or plasmin together with recombinant monocyte/macrophage chemotactic protein-1 (MCP-1) resulted in induction of psoriasiform skin inflammation around the injection sites with several aspects of human psoriasis in mice. CONCLUSIONS/SIGNIFICANCE: Plasmin converted from plasminogen by plasminogen activators plays an essential role in amplification of psoriasiform skin inflammation in mice, and targeting plasmin receptor--annexin II--may harbor therapeutic potential for the treatment of human psoriasis

Optimisation on the microwave drying of ammonium polyvanadate (APV):based on a kinetic study

Abstract Vanadium pentoxide (V₂O₅) is one of the fundamental materials applied in the productions of batteries, vanadium-aluminium alloys, biomedicine, catalysis, etc. High purity V₂O₅ can be prepared from an intermediate product, namely ammonium polyvanadate (APV), using roasting after a drying process. In this paper, microwave heating was used as an alternative drying option for APV, which has advantages including selective heating, high heating efficiency, energy-saving, and environmental protection. The authors investigated the microwave heating characteristics of APV and discussed the effects of microwave power, the mass of APV, and initial water content on the efficiency of microwave drying. The dynamic analysis of the APV microwave drying process was also carried out. Four groups of thin-layer drying dynamic models, namely Modified-Page model, Verma model, Sickmplified-Fick’s-diffusion model, and Two-term-exponential model, were fitted with the experimental data. Through comparison, the Modified Page model could better describe the microwave drying process of APV

Drying kinetics and microstructure evolution of nano-zirconia under microwave pretreatment

Abstract The effects of microwave power and sample quality on microwave drying kinetics and characteristics of zirconia were studied. It is found that by increasing the microwave power and decreasing the sample mass, the surface diffusion coefficient (Deff) appears to an upward tendency. The corresponding value Deff at a sample mass of 10, 20, 30, and 40g are 1.849E-14, 2.443E-14, 3.210E-14, and 3.278E-14 m²/s, respectively. The corresponding value Deff at a microwave power of 300, 400, 500, 600, and 700W are 1.270E-14, 1.784E-14, 2.619E-14, 3.392E-14, and 4.497E-14 m²/s, respectively. Besides, the materials were characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transforms infrared spectroscopy (FT-IR) to evaluate the changes of materials before and after drying. The results show that microwave accelerates the drying of zirconia and increases its dispersibility. The heat conduction direction of microwave drying is the same as that of moisture diffusion, which avoids being affected by heat inertia and heat transfer loss. The drying process is fast and efficient, and the microwave directly penetrates the product, avoiding the disadvantage of slow evaporation caused by the temperature gradient

Highly efficient oxidation of Panzhihua titanium slag for manufacturing welding grade rutile titanium dioxide

Abstract Because of the shortage of natural rutile, synthetic rutile is a widely used substitute welding materials for natural rutile owing to its excellent mechanical and thermal properties. In this work, rutile TiO2 was prepared from oxidation roasting titanium slag, which can be used as special welding materials. The phase microstructure characteristics of the raw materials and the roasted samples were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier-transform infrared (FT-IR) spectroscopic analysis. Results indicated that the contents of sulfur (S) and carbon (C) in titanium slag decreased during oxidation roasting process, and the decreases of sulfur and carbon contents were mainly ascribed to the formation of corresponding oxides. XRD and FT-IR results revealed the formation of rutile TiO₂ phase after titanium slag through oxidization roasting; additionally, observed from SEM patterns, the rutile TiO₂ phase with a complex short rod-like crystal appeared in the products. Since the contents of sulfur (S), phosphorus (P) and carbon (C) element were all below 0.030% in the prepared rutile TiO₂ with the recommended roasting approach (roasted at 1100 °C for 120 min), the present work highlights that Panzhihua titanium slag is a potential resource of titanium for the manufacture of high-quality rutile TiO₂ applicable for special welding materials industry

Crystal structure and thermomechanical properties of CaO-PSZ ceramics synthesised from fused ZrO₂

Abstract Partially stabilised zirconia (PSZ) ceramics have attracted much interest because of their outstanding properties. In this study, fused ZrO₂ was treated as a raw resource for the synthesis of CaO-PSZ ceramic materials through a facile sintering process. The crystal structure and thermomechanical properties of the synthesised CaO-PSZ ceramic samples were determined using XRD and SEM. The results revealed that various process parameters had different effects on the zirconia stability rate, including the temperature changing rate during the heating and cooling stages and the temperature and isothermal time during the quenching treatment; this was primarily a result of the thermodynamic characteristics of the martensitic conversion of ZrO₂ ceramics. Secondly, the martensitic conversion process was revealed by XRD patterns, expressed as the partial conversion of c-ZrO₂ to m-ZrO₂. Meanwhile, SEM-EDAX analysis highlighted the precipitation behaviour of the CaO stabiliser and the successful preparation of CaO-PSZ ceramics by sintering, represented by the gathering phenomenon of the acicular grains and particles, as the findings matched the stability rate analysis. This study can supply a sound reference for the synthesis of CaO-PSZ ceramics from fused ZrO₂

Phase stability and microstructure morphology of microwave-sintered magnesia-partially stabilised zirconia

Abstract In this work, microwave heating approach was introduced into the preparation process of zirconia materials to overcome the tricky technical defects during the traditional electric arc furnace method. Magnesia-partially stabilised zirconia (MgO-PSZ) with enhanced stability and a uniform microstructure was prepared via microwave heating of a ZrO₂ sample manufactured by the electric arc furnace method. The effects of microwave heating on the phase stability properties, microstructure, and surface morphology of the prepared MgO-PSZ sample were evaluated via X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, and Scanning electron microscopy, and the obtained results suggested that the stability rate of the MgO-PSZ sample improved from the initial value of 81.19%–94.82% after microwave heating at 1300 °C for 1 h. As a result of the martensitic conversion of ZrO₂ material, the m-ZrO₂ diffraction peaks were suppressed at the same time. Additionally, a similar changing trend was noticed in the XRD pattern, Raman spectrum, and FT-IR spectrum, indicating a decrease in the m-ZrO₂ phase content in the microwave treated products. Furthermore, the microstructure on the surface of the microwave-sintered MgO-PSZ sample was improved in contrast to the raw MgO-PSZ sample, and became relatively more uniform and smooth. This study determined the optimal microwave heating conditions for the preparation of MgO-PSZ material with enhanced performance, and can provided as a good foundation for developing the further related research on zirconia materials preparing by microwave heating technology

Phase microstructure and morphology evolution of MgO-PSZ ceramics during the microwave sintering process

Abstract In the present study, controllable microwave sintering was applied to prepare partially stabilised zirconia ceramics with enhanced phase composition and a more uniform structure. To reveal the phase interface properties and structural changes of PSZ ceramics during the microwave sintering process, XRD, FT-IR, Raman, and SEM characterisations were utilised. XRD analysis and Raman analysis demonstrated that the increase of sintering temperature promoted the martensite conversion. However, prolonging duration time was unconducive to the retention of the stable phase. Additionally, the FT-IR characteristic peak movement caused by the reversible phase martensite transformation was observed. Furthermore, SEM analysis found that microwave treatment improved the grain size and structure distribution of the as-received MgO-PSZ sample. This work constructed a controllable technical prototype of preparing PSZ ceramics via microwave sintering, which can provide a theoretical basis and experimental basis for further industrial production

Research on microwave drying technology in the procedure of preparation of V₂O₅ from ammonium polyvanadate (APV)

Abstract High-quality vanadium pentoxide powder is an important product of the vanadium industry and was usually prepared from ammonium polyvanadate (APV) using a roasting process combined with a drying pretreatment. Conventional hot air drying is usually used for the drying of APV, the heat transfer of which is from outside to inside thus limited the efficiency of the drying pretreatment. In the present paper, microwave heating was applied as an alternative heating method for the drying of APV because of its advantages including selective heating, high heating efficiency, low energy consumption, and green environmental protection. An experimental comparison between hot air drying and microwave drying is provided, and the results show that microwave drying is more energy-saving and faster. The drying characteristics of APV under the irradiation of microwave energy were investigated. The influences of factors including microwave power, material quality, and initial moisture content on microwave drying were studied. The results show that the microwave power, initial moisture content, and initial mass are positively proportional to the microwave drying efficiency of APV. Additionally, the Page model was robust in describing the kinetics of microwave drying and hot air drying of APV. This study provides fundamental knowledge on the microwave drying process and provides the trial for the industrial applications of microwave heating on the preparation of V₂O₅

Optimisation on the stability of CaO-doped partially stabilised zirconia by microwave heating

Abstract Partially stabilised zirconia has advantages for the applications in the metallurgical processes which have special requirements in corrosion resistance and high-temperature performance. In the present work, controllable microwave heating was used for the uniform thermal field and consequent microstructure improvement to further improve the stability of partially stabilised zirconia, which was 88.14% prepared by electric arc melting. Analyses including X-ray diffraction (XRD), Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy (Raman) were used to study the effect of temperature change on the phase composition and structure of the samples. After heating at temperatures of 900 °C, 1000 °C, 1100 °C, 1200 °C and 1300 °C for 1h, the stabilities of the heated product were 88.51%, 95.02%, 95.17%, 96.31% and 97.64%, respectively. From the phase transformations based on the experimental results, the discussion indicates that the martensitic transformation temperature of zirconia from m-ZrO₂ to t-ZrO₂ during the heating stage was reduced under the radiation of microwave energy