Matrilin-3-Primed Adipose-Derived Mesenchymal Stromal Cell Spheroids Prevent Mesenchymal Stromal-Cell-Derived Chondrocyte Hypertrophy

Adipose-derived mesenchymal stromal cells (Ad-MSCs) are a promising tool for articular cartilage repair and regeneration. However, the terminal hypertrophic differentiation of Ad-MSC-derived cartilage is a critical barrier during hyaline cartilage regeneration. In this study, we investigated the role of matrilin-3 in preventing Ad-MSC-derived chondrocyte hypertrophy in vitro and in an osteoarthritis (OA) destabilization of the medial meniscus (DMM) model. Methacrylated hyaluron (MAHA) (1%) was used to encapsulate and make scaffolds containing Ad-MSCs and matrilin-3. Subsequently, the encapsulated cells in the scaffolds were differentiated in chondrogenic medium (TGF-β, 1–14 days) and thyroid hormone hypertrophic medium (T3, 15–28 days). The presence of matrilin-3 with Ad-MSCs in the MAHA scaffold significantly increased the chondrogenic marker and decreased the hypertrophy marker mRNA and protein expression. Furthermore, matrilin-3 significantly modified the expression of TGF-β2, BMP-2, and BMP-4. Next, we prepared the OA model and transplanted Ad-MSCs primed with matrilin-3, either as a single-cell suspension or in spheroid form. Safranin-O staining and the OA score suggested that the regenerated cartilage morphology in the matrilin-3-primed Ad-MSC spheroids was similar to the positive control. Furthermore, matrilin-3-primed Ad-MSC spheroids prevented subchondral bone sclerosis in the mouse model. Here, we show that matrilin-3 plays a major role in modulating Ad-MSCs’ therapeutic effect on cartilage regeneration and hypertrophy suppression.     

Highly ordered microstructures of poly(styrene-b-isoprene) block copolymers induced by solution meniscus

Microstructures of hundreds of micron thick poly(styrene-block-isoprene) copolymer films solution-cast in a cylindrical tube with the solvent evaporation controlled were investigated by transmission electron microscope (TEM), small angle X-ray scattering (SAXS) and optical microscope (OM). In a block copolymer with cylindrical polyisoprene microdomains, the orientation of the cylinders was varied along radial direction of the cylindrical tube. Highly aligned hexagonal arrays of in-plane polyisoprene cylinders were formed with their cylindrical axis parallel to the circumference of the tube in the regimes close to the wall edge. In contrast randomly ordered microdomains were observed at the center of the tube. We have also found that the orientation depends on the solvent evaporation rate and an intermediate rate (∼2.3 nL/s) provides the best orientation. In the case of a block copolymer with a bicontinuous double gyroid structure, we obtained a globally ordered microstructure where [111] crystallographic direction was parallel to the circumference of the tube. For both block copolymers, the area of highly ordered arrays of nanoscopic domains is over 1 mm². Development of the orientation was explained by coupling two orthogonal fields: (1) The flow of a solution induced by strong capillary force at a meniscus between the cylindrical tube wall and the block copolymer solution and (2) the solvent evaporation.     

On-line mass spectrometry system for measurements at single-crystal electrodes in hanging meniscus configuration

We present the construction and some first applications of an On-line electrochemical mass spectrometry system for detecting volatile products formed during electrochemical reactions at a single-crystal electrode in hanging meniscus configuration. The system is based on a small inlet tip made of porous Teflon and a Peek holder, which is brought in close proximity (ca. 10–20 μm) to the electrode surface. The tip is connected to the mass spectrometer by glass and metal tubing. Because of the small amount of gas entering the mass spectrometer, no differential pumping is needed during the measurement. The tip construction and preparation introduced here leads to reproducible voltammetry with very good cleanliness characteristics. The presence of the tip has no significant influence on the blank voltammetry of a Pt(111) in sulfuric acid, and on voltammetric responses for CO adlayer oxidation, methanol oxidation, and hydroxylamine electrochemistry on Pt(111). The formation of gaseous products in these reactions can be followed accurately and is in good agreement with earlier results obtained by other mass spectrometric or spectroscopic techniques. The time response and tailing of the setup is on the order of seconds and mainly determined by the distance between the tip and the electrode.     

连铸结晶器振动下弯月面处温度波动的模拟实验

设计了连铸结晶器弯月面处传热模拟实验，测量了在结晶器振动情况下弯月面处的温度，发现该处的温度随着结晶器的振动而产生周期性的变化，实验结果表明，结晶器振动频率越大，振动幅值，结晶器冷却强度以及结晶器与铸坏间的接触压力越小，因结晶器振动而产生的弯月面温度波动亦越小，据此认为，连铸弯月面温度波动是导致铸坯表面缺陷产生的一个重要原因，基于此“温度波动”现象，分析了包括高频小振幅振动，软接触结晶器电磁连铸，热顶结晶器等诸多技术改善坯表面质量的机理。     

电磁场作用下板坯连铸结晶器内的弯月面行为

用Pb-Sn-Bi低熔点合金进行了热模拟实验.从液面波动人手,研究了在单条形电磁场作用下板坯连铸结晶器内的弯月面行为.实验结果表明可应用磁场控制结晶器内金属液面的波动.当水口角度为向下30°时,磁场对表面波动的抑制作用有一最佳值,即磁感应强度为0.5 T时液面平均波动最小,液面较稳定.施加磁场使弯月面处温度明显提高,使水口出流的向下冲击深度受到抑制,这有利于夹杂物的上浮分离,达到提高板坯内部质量的目的.     

Wetting forces and meniscus pinning at geometrical edges

It is shown that complications in currently used optical measurements for wetting and flow resistance over edges can be circumvented by surface tension force measurements. These forces are measured by employing a modified Wilhelmy plate testing technique in which a plate with rectangular holes is immersed. The forces measured during immersion and emersion are subdivided into mass, buoyancy, and surface tension related parts, where the flow resistance when the meniscus passes horizontal faces and edges of the plate receives particular attention. Combining this experimental method with wetting theory, we show that we can predict and measure the full force curve for meniscus shape transitions over edge geometries under quasi‐static conditions. Moreover, wetting effects directly linked to surface defects can be detected qualitatively. We also point to the speed‐dependent rupture of metastable films formed during emersion. The measurement method designed is most relevant in cases where optical methods cannot be used. © 2016 The Authors AIChE Journal published by Wiley Periodicals, Inc. on behalf of American Institute of Chemical Engineers AIChE J, 62: 4453–4465, 2016     

Thermal Analysis of Nanofluids on the Thin Film Evaporation of Meniscus

A mathematical model for predicting evaporation in the thin film region was developed and its analytical solutions were obtained for thin‐film thickness, the heat transport per unit length and the total heat flux transport in the thin‐film region. These analytical solutions show that the higher heat flux through the thin film region occurs due to the higher superheat. The maximum evaporative rate occurs when the effects of the increase in the temperature difference and in the thin film thickness on the heat flux q stay equal. A nanofluid, which is a colloidal mixture of nanoparticles (1 nm to 100 nm) and a base liquid (nanoparticle fluid suspensions), is employed as the working fluid. In a certain range, increasing the volume fraction of nanoparticles in the base fluid leads to decreasing the kinematic viscosity of the nanofluid and increasing the thermal conductivity, which influences the evaporation in the thin film region. The heat transfer rate per unit length and the total heat flux in the thin film region display various characteristics among the different type of nanofluids due to the differences of the kinematic viscosity and the thermal conductivity.     

中间切缝圆坯连铸结晶器内弯月面行为的试验研究

采用Sn-Pb-Bi低熔点合金模拟钢液对高频电磁场作用下中间切缝圆坯连铸结晶器内的弯月面行为进行研究,从弯月面形状、高度和三相点位置等方面入手分析,讨论了电源功率、感应线圈位置和磁场频率对弯月面行为的影响,并以钢液为试验材料进行模型试验,验证了采用Sn-Pb-Bi低熔点合金进行研究的可靠性。结果表明,电功率对弯月面行为影响较明显;感应线圈的最佳安装位置位于结晶器切缝区域中心;在20～30kHz范围内增加磁场频率可以有效提高弯月面高度,但当磁场频率超过30kHz后,弯月面高度增加幅度不明显;在相似的试验条件下,钢液弯月面轮廓线接近于合金熔液的弯月面,这表明采用Sn-Pb-Bi低熔点合金熔液可以准确地模拟钢液的弯月面行为。     

米级弯月面化学薄膜涂覆装备的研制

弯月面化学涂膜技术因其具有大面积、低成本以及高效率等优势成为继旋涂、喷涂等传统涂膜工艺后极具发展潜力的新型化学薄膜涂覆技术。本文针对国家某重大项目对米级光学元件表面的化学薄膜涂覆需求,对基于弯月面涂胶的技术原理进行了系统研究,分析了涂胶压强、基片和狭缝间距以及材料亲疏水性与涂胶面形态的关系,实现了对弯月液面的精密调控并研制出基于弯月面化学薄膜涂覆技术的装备,在1 400mm×420mm尺寸玻璃基片上实现了光刻胶的均匀涂覆,使整体胶膜厚度误差4%,满足了米级元件表面精密化学薄膜的涂覆需求。     

Study on high performance evaporator with micro‐grooves (Measurement of capillary force in a single groove and modeling of heat and mass transfer)

A micro‐grooved evaporator is composed of µm‐wide grooves on a heat transfer plate in which the inter‐line regions at the liquid–vapor meniscus of coolant become identifiable. The high‐heat performance of the evaporator is realized by this inter‐line region (ILR) where the liquid thin film reduces the thermal resistance on the heat transfer surface. In this report, we propose a numerical simulation model of heat and mass transfer in a single groove to predict its capillary force and heat flux. The capillary force performance (capillary‐rise length in a groove) of a single groove was measured for samples of varying width, superheat, and inclination. The performance was found to be a maximum at a specific groove width of 200–400 µm, which is in good agreement with the predicted results calculated by the proposed model. For a better prediction of capillary‐rise length, the effective capillary force and the effective flow resistance were considered. © 2009 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.20257