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.     

非洲爪蟾卵提取物中200nm膜泡与环形片层及核被膜上核孔复合体形成的关系

将ＬａｍｂｄａＤＮＡ引入活化的非洲爪蟾卵提取物中，在由磷酸肌酸与磷酸肌酸激酶构成的ＡＴＰ再生系统的参与下，在这种非细胞体系中能够围绕由ＬａｍｂｄａＤＮＡ诱导形成的染色质重建核被膜结构，同时在染色质外出现类似核被膜结构的环形片层。在这两种膜结构中核孔复合体的形成都与直径２００ｎｍ左右的单层圆形小膜泡密切相关，这些小膜泡可以附着在染色质表面或独立于染色质之外相互融合成扁平囊状的双层膜片层，双层膜进一步融合形成核孔，与此同时，核孔复合体在核孔上完成装配。     

Chemistry and Physics of Alkali Metals on MoS2 Surfaces

The interaction of alkali metal with surfaces has been of great interest to the community of catalysis since alkali metal can play an important role as a promoter. On alkali-doped MoS₂, such a promotion effect of alkali metal has been exemplified in the direct synthesis of linear alcohols from CO and H₂, where the alkali-doping switches the catalyst selectivity from methanation to alcohol synthesis. This paper reviews recent high-resolution X-ray photoelectron spectroscopy experiments that have provided direct observation of electron transfer from alkali metals to a model single crystal MoS₂ and the capture of the supra-valence electrons in the subsequent oxidation reactions.     

Fluctuating NMDA Receptor Subunit Levels in Perirhinal Cortex Relate to Their Dynamic Roles in Object Memory Destabilization and Reconsolidation

Reminder cues can destabilize consolidated memories, rendering them modifiable before they return to a stable state through the process of reconsolidation. Older and stronger memories resist this process and require the presentation of reminders along with salient novel information in order to destabilize. Previously, we demonstrated in rats that novelty-induced object memory destabilization requires acetylcholine (ACh) activity at M₁ muscarinic receptors. Other research predominantly has focused on glutamate, which modulates fear memory destabilization and reconsolidation through GluN2B- and GluN2A-containing NMDARs, respectively. In the current study, we demonstrate the same dissociable roles of GluN2B- and N2A-containing NMDARs in perirhinal cortex (PRh) for object memory destabilization and reconsolidation when boundary conditions are absent. However, neither GluN2 receptor subtype was required for novelty-induced destabilization of remote, resistant memories. Furthermore, GluN2B and GluN2A subunit proteins were upregulated selectively in PRh 24 h after learning, but returned to baseline by 48 h, suggesting that NMDARs, unlike muscarinic receptors, have only a temporary role in object memory destabilization. Indeed, activation of M₁ receptors in PRh at the time of reactivation effectively destabilized remote memories despite inhibition of GluN2B-containing NMDARs. These findings suggest that cholinergic activity at M₁ receptors overrides boundary conditions to destabilize resistant memories when other established mechanisms are insufficient.     

Stochastic defect diffusion model for relaxation effects in crystalline polyethylene

It is suggested that some relaxation processes observed in crystalline polyethylene are consequences of the diffusive motion of a particular defect called a point dislocation or twist dispiration loop along the polyethylene stems in lamellar crystals. The motion of the defect, characterized by a diffusion coefficient and a mobility, is described by solutions of the Smoluchowski diffusion equation with boundary conditions that constrain the defect to move along routes that produce experimentally observable results. The fact that passage of the defect causes both a 180° rotation of the chain and moves an extra CH₂ group in the direction of the chain axis is important to the interpretation of the data according to this model. The diffusion coefficient for a defect is estimated to be around 2 × 10^?9 cm² s^?1 at 70°C. This value is shown to be reasonable both from the viewpoint of detailed computer modelling of defect motion and contemporary ideas about scaling.     

共晶形貌选择及界面失稳的多相场模拟

采用KKSM多相场模型，研究了低速下定向凝固CBr4-C2Cl6薄试样的层片共晶界面失稳及形貌选择．多相场模拟结果真实再现了3种共晶层片界面失稳模式及其形貌选择的演化过程，随着初始层片间距的不断增加，其形貌选择变化依次为：层片湮没→稳态生长→1λO不稳定性→2λO不稳定性→层片分叉与形核．模拟结果不仅与理论计算的形貌选择图相符，而且与实验结果定性一致．     

内高压成形工艺的应力应变及工艺失稳分析

以研究内高压成形工艺的成形机理为目的,利用塑性力学方法分析了内高压成形过程中坯料的应力特点以及其在成形不同阶段的应力状态区别和变化规律.根据增量理论给出了成形过程中的应变增量形式及相应公式,指出了厚向应变是内高压成形工艺顺利实施的关键,并从应力应变的角度给出了工艺中不同失稳形式的应力应变特征.     

车轮断裂韧性与组织和性能的关系

研究了车轮断裂韧性与组织性能的关系。结果表明，所分析的三个车轮中(分别编为D1，D2和E1)，D1和D2车轮的KQ值分别比E1车轮的KQ值高30．0％和低14．5％。裂纹尖端延伸区宽度和铁素体百分含量与KQ值之间存在正相关关系，铬、Ceq和晶粒尺寸与KQ值之间存在负相关关系，珠光体片间距约为0．6μm时断裂韧性最高。     

Mg3Cd: A model alloy for studying the destabilization of magnesium hydride

We prepared an ordered Mg₃Cd alloy by high energy ball milling of elemental powders. The synthesized alloy exhibited good hydrogenation kinetics and reversibly absorbed about 2.8 wt. % of hydrogen. The temperature dependence of hydrogenation kinetics of the alloy measured in the range of temperatures covering the order-disorder phase transformations in the Mg₃Cd and MgCd phases did not exhibit any anomalies and could be fitted with a single Arrhenius line. The measured apparent activation energy (69 ± 2 kJ/mol) hinted that hydrogenation process was controlled by diffusion of Cd in metallic phase. The pressure-composition isotherms exhibited negligible pressure hysteresis and sloping pressure plateau. Based on microstructural evidence obtained with the aid of X-ray diffraction and scanning electron microscopy, we built a thermodynamic model predicting the plateau hydrogen pressure for partially hydrogenated alloy. The predictions of the model were in a good agreement with the experimental data. Finally, we discussed the origins and the growth mechanisms of Cd whiskers observed in the alloys after full hydrogenation cycle.     

提高工业锅炉热效率的途径

详细分析论述了降低q4热损失，提高链条炉热效率的途径，主要包括炉前燃煤的处理和燃烧设备的改造。