隐匿性房室旁道心电图定位的临床价值评价

目的探讨隐匿性房室旁道心电It定位的临床价值。方法以我院2010年-2013年诊断收治的隐匿性房室旁道患者48例为研究对象。结果右侧旁道13例,在V1倒置12例,平坦3例,P-R间期均〉R—P-间期,左侧旁道35例,其中21例左前区域旁道,在I、aVLP-波倒置,在III、aVFP-波直立,P-R间期均〈R—P-间期;14例左后区域旁道,12例P-波在I、aVL直立、浅倒置、平坦,各种变化较大,P-R间期〉R—P-间期,2例左后间隔旁道在III、aVFP。波深倒置。结论隐匿性房室旁道诊断中采用体表心电图通过对P-波形态以及RP间期长短的观察能形成较为准确的定位。     

Phase Transformation after Heat Treatment of Cr-Ni Stainless Steel Powder for 3D Printing

Today, Ni-Cr steel is used for advanced applications in the high-temperature and electrical industries, medical equipment, food industry, agriculture and is applied in food and beverage packaging and kitchenware, automotive or mesh. A study of input steel powder from various stages of the recycling process intended for 3D printing was conducted. In addition to the precise evaluation of the morphology, particle size and composition of the powders used for laser 3D printing, special testing and evaluation of the heat-treated powders were carried out. Heat treatment up to 950 °C in an air atmosphere revealed the properties of powders that can appear during laser sintering. The powders in the oxidizing atmosphere change the phase composition and the original FeNiCr stainless steel changes to a two-phase system of Fe₃Ni and Cr₂O₃, as evaluated by X-ray diffraction analysis. Observation of the morphology showed the separation of the oxidic phase in the sense of a brittle shell. The inner part of the powder particle is a porous compact core. The particle size is generally reduced due to the peeling of the oxide shell. This effect can be critical to 3D printing processing, causing defects on the printed parts, as well as reducing the usability of the precursor powder and can also change the properties of the printed part.     

Changes in antioxidant,inflammatory and metabolic markers during 1 week cultivation of human skin explants

Human skin explant (HSE) seems to be a useful model for dermatological/cosmetic testing. HSE prepared from donor superfluous skin from plastic surgery operations is cheap and easily obtainable compared to reconstructed models. The HSE use, however, may be limited by the degeneration processes during cultivation. The aim was to monitor changes in metabolic activity and selected apoptotic, inflammatory and antioxidant parameters during 7 day cultivation. The significant changes were found in the superoxide dismutase‐2 level from day 5, glutathione S‐reductase level from day 6, metabolic activity and fibulin‐5 level from day 4, cyclooxygenase‐2, interleukin‐6 and interleukin‐10 from day 1 to 2. Other selected markers (lipid peroxidation products and glutathione level, glutathione S‐transferase, catalase, superoxide dismutase and glutathione S‐reductase activity, glutathione peroxidase and glutathione S‐reductase levels) were not modified significantly due to high inter‐individual variability of skin donors. The HSE microstructure as well as cytokeratin‐10 and proliferation marker Ki67 expression was also only minimally affected during cultivation. Collectively, the results demonstrate that HSE represents a good model for short‐term studies focused on the physical and chemical agent toxicity, protective potential of compounds or metabolic biotransformation. However, reduced metabolic activity, increased inflammation and the high inter‐individual variability and sensitivity of donors have to be taken into consideration.