Quantitative and reliable in vitro method combining scanning electron microscopy and image analysis for the screening of osteotropic modulators

The increased generation and up-regulated activity of bone resorbing cells (osteoclasts) play a part in the impairment of bone remodeling in many bone diseases. Numerous drugs (bisphosphonates, calcitonin, selective estrogen receptor modulators) have been proposed to inhibit this increased osteoclastic activity. In this report, we describe a pit resorption assay quantified by scanning electron microscopy coupled with image analysis. Total rabbit bone cells with large numbers of osteoclasts were cultured on dentin slices. The whole surface of the dentin slice was scanned and both the number of resorption pits and the total resorbed surface area were measured. Resorption pits appeared at 48 h and increased gradually up to 96 h. Despite the observation of a strong correlation between the total resorption area and the number of pits, we suggest that area measurement is the most relevant marker for osteoclastic activity. Osteotropic factors stimulating or inhibiting osteoclastic activity were used to test the variations in resorption activity as measured with our method. This reproducible and sensitive quantitative method is a valuable tool for screening for osteoclastic inhibitors and, more generally, for investigating bone modulators.     

同步发电机中不可直接测量量的左逆软测量方法

研究了同步发电机中一些不可直接测量量（功角、 dq轴暂态电势、dq轴电流分量等）的动态软测量问题。首先,建立了适合于软测量分析的同步发电机模型,该模型充分包含了同步发电机中的一些可直接测量量（如有功功率、无功功率、电流幅值等）,且是一类特殊的非线性微分 — 代数子系统。接着,针对所建立模型的特殊性,给出了适合此模型的推广的左逆软测量算法。然后,具体针对同步发电机的4阶实用模型设计了软仪表,实现了模型中所有不可直接测量量的软测量。最后,基于MATLAB/SimPowerSystems软件进行了数值仿真,用6阶次暂态模型模拟真实的同步发电机,验证了所提出的方法的有效性。     

Nd~(3 )、Dy~(3 )、Yb~(3 )与L-酪氨酸甘氨酸三元固态配合物的合成与表征

在乙醇溶液中合成了三种稀土与Ｌ－酪氨酸、甘氨酸的三元固态配合物ＲＥ（Ｔｙｒ）１．５（Ｇｌｙ）４（ＣｌＯ４）３（ＲＥ＝Ｎｄ３＋、Ｄｙ３＋、Ｙｂ３＋）。并通过摩尔电导、红外光谱、热谱等进行了表征。     

A preclinical study of the effect of the animal polysaccharide chonsurid on reparative osteogenesis of the jaws

Experimental studies making use of morphological and x-ray methods demonstrated that in comparison with control (filling of mandibular bone defects with blood clots) chonsuride, an animal polysaccharide, promoted earlier filling of postoperative bone cavities with connective tissue replacement of this tissue with coarse-fiber bone tissue. Secondary restructuring and mineralization of bone regenerate were enhanced as well.     

Characterization of multilayer anti-fog coatings

Fog formation on transparent substrates constitutes a major challenge in several optical applications requiring excellent light transmission characteristics. Anti-fog coatings are hydrophilic, enabling water to spread uniformly on the surface rather than form dispersed droplets. Despite the development of several anti-fog coating strategies, the long-term stability, adherence to the underlying substrate, and resistance to cleaning procedures are not yet optimal. We report on a polymer-based anti-fog coating covalently grafted onto glass surfaces by means of a multistep process. Glass substrates were first activated by plasma functionalization to provide amino groups on the surface, resulting in the subsequent covalent bonding of the polymeric layers. The anti-fog coating was then created by the successive spin coating of (poly(ethylene-maleic anhydride) (PEMA) and poly(vinyl alcohol) (PVA) layers. PEMA acted as an interface by covalently reacting with both the glass surface amino functionalities and the PVA hydroxyl groups, while PVA added the necessary surface hydrophilicity to provide anti-fog properties. Each step of the procedure was monitored by XPS, which confirmed the successful grafting of the coating. Coating thickness was evaluated by profilometry, nanoindentation, and UV visible light transmission. The hydrophilic nature of the anti-fog coating was assessed by water contact angle (CA), and its anti-fog efficiency was determined visually and tested quantitatively for the first time using an ASTM standard protocol. Results show that the PEMA/PVA coating not only delayed the initial period required for fog formation but also decreased the rate of light transmission decay. Finally, following a 24 hour immersion in water, these PEMA/PVA coatings remained stable and preserved their anti-fog properties.     

金属针布钢丝的球化退火工艺

介绍纺织行业金属针布的现状及针布钢丝生产的工艺流程。详细分析金属针布钢丝球化退火的目的、种类、机制及其影响因素,介绍国内外球化退火的设备,并对球化退火钢丝的质量进行评价,对针布钢丝的生产提出几点建议。     

Correlation between structural and electrical properties in highly porous (Y,Sr)(Ti,Nb)O3−δ SOFC anodes

In order to find a relationship between structural and electrical properties, niobium and yttrium doped SrTiO₃ ceramics were prepared via solid-state reaction. The samples were sintered in hydrogen and air conditions. The samples were also fabricated with a pore-former to obtain highly porous specimens. The electrical properties of Nb-doped SrTiO₃ samples and yttrium and niobium co-doped SrTiO₃ were compared. The comparable electrical properties were observed and discussed according to previous literature reports. It was noticed that the synthesis in a reducing hydrogen atmosphere can increase the solubility of dopants. Moreover, the samples sintered in air presented lower conductivity level and worse structural properties than the samples sintered in hydrogen. The explanation of obtained results was also suggested and discussed.     

Centrifuge modeling of the geotextile reinforced slope subject to drawdown

Geotextile is an effective reinforcement approach of slopes that experiences various loads such as drawdown. The geotextile reinforcement mechanism is essential to effectively evaluate the safety of geotextile-reinforced slopes under drawdown conditions. A series of drawdown centrifuge model tests were performed to investigate the deformation and failure behaviors of slopes reinforced with different geotextile layouts. The deformation and failure of unreinforced and reinforced slopes were compared and the geotextile reinforcement was indicated to significantly increase the safety limit and the ductility, reduce the displacement, and change the failure feature of slopes under drawdown conditions. The slopes exhibited remarkable progressive failure, downward from the slope top, under drawdown conditions. The progressive failure was induced by coupling of deformation localization and local failure based on full-field measurements of displacement of slopes subjected to drawdown. The geotextile reinforced the slope by decreasing and uniformizing the slope deformation by the soil-geotextile interaction. Through geotextile displacement analysis, the geotextile-reinforced slope was divided into the anchoring zone and the restricting zone by a boundary that was independent of the decrease of water level. The geotextile restrained the soil in the anchoring zone and the soil restrained the geotextile in the restricting zone. The reinforcement effect was distinct only when the geotextile was long enough to cross the slip surface of the unreinforced slope under drawdown conditions.