Angioarchitectural form, functional distributive pattern and classification of the fungiform papillae on the crossbred Japanese cat tongue anterodorsal surface in scanning electron microscopic specimens

The purpose of this study was to undertake a three-dimensional comparative observation of the angioarchitectural form, functional distributive pattern, and to classify the fungiform papillae (FuP) found sporadically and geometrically on the oblique lines of the filiform papillae (FiP) on the entire dorsal surface of the crossbred Japanese cat foretongue in microvascular cast specimens (MVCS). By means of the corrosive resin casting technique, the MVCS of the FuP of the cat tongue were prepared and examined in detail under the scanning electron microscope (SEM). With regard to the arrangement of FiPs and FuPs on the frontal half of the antero-dorsal surface of the cat foretongue, FiP types I-V and FuP types I-IV are arranged a A form with the point in the direction of the apex and in an oblique line running from the antero-central portion to both postero-peripheral portions. In the rear half of the antero-dorsal surface of the foretongue, FiP types I-V and types FuP I-IV are arranged in a V form with the point in the direction of the radix and in an oblique line running from both antero-peripheral portions to the postero-median portion or towards the pharynx on the anterior centro-dorsal surface of the cat foretongue. With the FuP arranged in the medial zone (M) and peripheral zone (P) running from the central to the apical parts, both the peripheral parts and the pharyngeal can be classified into four types (FuP types I-IV) according to the shape and size of the main process (MP), the number of the accessory processes (AP) and the regional position of the lozenge arrangement. FuP Types I-III consisted of a MP containing a large half oval, network-like process, and the AP contained a bundle of spine-like processes arranged radially in a circle at the anterior basal margin of the MP. The FuP Type IV was made up of only one MP. In the central zone (C) of a lozenge part arranged in the A and V forms, there was no FuP as a taste organ. It was assumed that in the lozenge arrangement of the A and V forms, except for the C zone, FuPs could be classified into four types (FuP types I-IV) from the frontal portion of the antero-dorsal surface toward the pharynx on the foretongue, and would play an assistant functional role in receiving the sense of taste of foods and liquids.     

316L不锈钢微动过程缝隙腐蚀倾向研究

采用球-平面接触微动磨损设备,对轧制固溶316L不锈钢在NaCl溶液微动过程缝隙腐蚀行为进行了研究。通过静、动态电化学测试及材料微动磨蚀形貌观察。揭示了316L不锈钢在NaCl溶液中的微动腐蚀机理。316L不锈钢微动过程具有显缝隙腐蚀倾向,而溶液腐蚀特性与材料缝隙腐蚀的发生、发展有密切关系。     

口腔环境中钛及钛合金腐蚀研究现状

本文介绍了腐蚀学的定义变迁、分类及研究医用金属腐蚀的方法。对钛材料腐蚀原因及口腔介质环境服役中出现腐蚀现象进行了分析 ,得出钛材在口腔服役环境中发生腐蚀与口腔环境介质变化、咀嚼活动参与密切相关。     

Comparative angioarchitectural formation seen in microvascular cast specimens of the fungiform papillae in the weaning period and adult rat tongue

The purpose of this study was an attempt to identify the functional and comparative angioarchitectural differences between the sexes, and the developmental processes seen in microvascular cast specimens (MVCS) of the formation of the fungiform papillae (FuP) geometrically and regularly distributed on the anterodorsal surface in the weaning period and in the adult rat tongue. The basic microvascular structure seen in the MVCS of FuP of both the weaning and adult rat tongue consisted of several ascending (As. b) and descending branches (Ds. b) and a loop structure (L. st), and the cylindrical network structure of the L. st made up of the open-hole formation of the C form of the upper and lower microvascular structures. In the lateral view, the MVCS of FuP has a bamboo basket-like shape, and by means of the three-dimensional expansion of the surface area, effectively plays an assistant functional role in receiving the taste of foods and liquids. There were obviously no sex and morphological differences in the developmental process as to shape, but there was some difference between the weaning period and the adult rat in size in the MVCS of FuP.     

直丝弓矫治器矫治完成病例牙 模型牙位的分析

目的评价采用国产Roth直丝弓矫治器矫治完成后的病人是否具有理想的关系及准确的牙齿位置。方法测量分析30付牙模型右侧磨牙关系距离、磨牙补偿角(offsetofmolar)、各个牙齿唇舌向及颊舌向倾斜度(Torque)、牙齿近远中倾斜度(Tip)、旋转度、牙间间隙、Spee氏曲线和牙冠凸度。结果(1)30付牙模型中未有一付完全达到Andrews的六项标准、其中第一恒磨牙关系、牙间隙、Spee氏曲线三项符合率较高、而转矩角、轴倾角旋转度三项则符合率较低。(2)上下前牙轴倾角均大于中国人正常正常值、上下尖牙尤其明显。(3)第一恒磨牙的冠凸度及补偿角明显小于中国人正常值。结论为了更适合中国人,应对国产Roth直丝弓矫治器设计数据进行一些改进。此外,在矫治完成阶段,正畸医生应对弓丝进行必要的艺术及技巧上的处理以达到理想的牙齿位置,但其调整量则远远少于方丝弓矫治器。     

Synthesis of Novel Nano-Sulfonamide Metal-Based Corrosion Inhibitor Surfactants

The synthesis of novel corrosion inhibitors and biocide metal complex nanoparticle surfactants was achieved through the reaction of sulfonamide with selenious acid to produce a quaternary ammonium salt. Platinum and cobalt surfactants were then formed by complexing the first products with platinum (II) or cobalt (II) ions. The surface properties of these surfactants were then investigated, and the free energy of form micelles (ΔG_omic) and adsorption (ΔG_oads) was determined. The obtained cationic compounds were evaluated as corrosion inhibitors for carbon steel dissolution in 1N HCl medium. The results of gravimetric and electrochemical measurements showed that the obtained inhibitors were excellent corrosion inhibitors. The anti-sulfate-reducing bacteria activity known to cause corrosion of oil pipes was obtained by the inhibition zone diameter method for the prepared compounds, which were measured against sulfate-reducing bacteria. FTIR spectra, elemental analysis, H1 NMR spectrum, and 13C labeling were performed to ensure the purity of the prepared compounds.     

Compositional Tailoring of Mg–2Zn–1Ca Alloy Using Manganese to Enhance Compression Response and In-Vitro Degradation

The present study investigates Mg–2Zn–1Ca/XMn alloys as biodegradable implants for orthopedic fracture fixation applications. The effect of the presence and progressive addition of manganese (X = 0.3, 0.5, and 0.7 wt.%) on the degradation, and post-corrosion compressive response were investigated. Results suggest that the addition of manganese at 0.5 wt.% improved the corrosion resistance of Mg–2Zn–1Ca alloys. The pH values stabilized for the 0.5Mn-containing alloy and displayed a lower corrosion rate when compared to other Mg–2Zn–1Ca/Mn alloys. Mg–2Zn–1Ca showed a progressive reduction in the compressive strength properties at the end of day 21 whereas Mg–2Zn–1Ca/0.3Mn and Mg–2Zn–1Ca/0.5Mn samples showed a decrease until day 14 and stabilized around the same strength range after day 21. The ability of Mg–2Zn–1Ca/0.5Mn alloy to develop a network of protective hydroxide and phosphate layers has resulted in the corrosion control of the alloy. Mg–2Zn–1Ca/0.7Mn displays segregation of Mn particles at the grain boundaries resulting in decreased corrosion protection. The mechanism behind the corrosion protection of Mg–2Zn–1Ca alloys was discussed.     

前牙美容修复中IPS Empress 2新型铸瓷系统应用的可行性及安全性

目的:探讨前牙美容修复中IPS Empress 2新型铸瓷系统应用的可行性及安全性。方法:选取2011年5月~2014年5月四川省广安市人民医院口腔科收治的46例(118颗牙)需要接受前牙全瓷冠修复的患者,依据随机数字表法将这些患者分为两组,即观察组23例(59颗)和对照组23例(59颗)。给予对照组患者传统钴铬合金的烤瓷冠修复,给予观察组患者IPS Empress 2新型铸瓷贴面修复。结果:观察组患者对修复体颜色、修复体外形、修复体舒适度的满意度100%(23/23)、100%(23/23)、95.6%(22/23)均明显比对照组78.3%(18/23)、82.6%(19/23)、73.9%(22/23)高(P0.05);治疗后0.5年观察组患者的边缘适合度、牙敏感症状、颜色匹配均明显比对照组好(P0.05),治疗后3年观察组患者的边缘适合度、牙龈健康状况、颜色匹配均明显比对照组好(P0.05)。结论:前牙美容修复中应用IPS Empress 2新型铸瓷系统安全可行。     

Corrosion behaviour and surface analysis of a Co-Cr and two Ni-Cr dental alloys before and after simulated porcelain firing

This study evaluated the corrosion behaviour and surface properties of a commercial cobalt-chromium (Co-Cr) alloy and two nickel-chromium (Ni-Cr) alloys [beryllium (Be)-free and Be-containing] before and after a simulated porcelain-firing process. Before porcelain firing, the microstructure, surface composition and hardness, electrochemical corrosion properties, and metal-ion release of as-cast alloy specimens were examined. After firing, similar alloy specimens were examined for the same properties. In both as-cast and fired conditions, the Co-Cr alloy (Wirobond C) showed significantly more resistance to corrosion than the two Ni-Cr alloys. After firing, the corrosion rate of the Be-free Ni-Cr alloy (Stellite N9) increased significantly, which corresponded to a reduction in the levels of Cr, molybdenum (Mo), and Ni in the surface oxides and to a reduction in the thickness of the surface oxide film. The corrosion properties of the Co-Cr alloy and the Be-containing Ni-Cr alloy (ChangPing) were not significantly affected by the firing process. Porcelain firing also changed the microstructure and microhardness values of the alloys, and there were increases in the release of Co and Ni ions, especially for Ni from the Be-free Ni-Cr alloy. Thus, the corrosion rate of the Be-free Ni-Cr alloy increased significantly after porcelain firing, whereas the firing process had little effect on the corrosion susceptibility of the Co-Cr alloy and the Be-containing Ni-Cr alloy.     

Corrosion Damage to Joints of Lattice Towers Designed from Weathering Steels

The article dealt with the load-bearing capacity and durability of power line lattice towers designed from weathering steel. Attention was paid in particular to the bolted lap joints. The article evaluates the static and corrosion performance of bolted lap joints in long-term operating towers, and also presents and evaluates design measures that can be applied in the design of new lattice towers, or in the reconstruction of already operating structures. Power line lattice towers are the most extensive realization of weathering steel in the Czech Republic. On the basis of the inspections carried out to evaluate the working life of the transmission towers in operation, it can be stated that a sufficiently protective layer of corrosion products generally developed on the bearing elements of the transmission towers. However, the development of crevice corrosion at the bolted joints of the leg members is a significant problem. In this paper, the corrosion damage of bolted joints was evaluated considering two basic aspects: (1) the influence of crevice corrosion on the bearing capacity of the bolted joint was evaluated, using experimental testing and based on analytical and numerical calculations; (2) appropriate design measures applicable to the rehabilitation of developed crevice corrosion of in-service structures, or the elimination of crevice corrosion in newly designed lattice towers, was evaluated. Calculation analyses and destructive tests of bolted joints show that the development of corrosion products in the crevice does not have a significant effect on the bearing capacity of the joint, provided that there is no significant corrosion weakening of the structural elements, and bolts of class 8.8 or 10.9 are used. The results of the long-term experimental programme, and the experience from the rehabilitations carried out, show that, thanks to appropriate structural measures, specified in detail in the paper, the long-term reliable behaviour of the lattice towers structures is ensured.