Enamel Matrix Derivative Promote Primary Human Pulp Cell Differentiation and Mineralization

Enamel matrix derivative (EMD) has been found to induce reactive dentin formation; however the molecular mechanisms involved are unclear. The effect of EMD (5–50 μg/mL) on primary human pulp cells were compared to untreated cells and cells incubated with 10⁻⁸ M dexamethasone (DEX) for 1, 2, 3, 7, and 14 days in culture. Expression analysis using Affymetrix microchips demonstrated that 10 μg/mL EMD regulated several hundred genes and stimulated the gene expression of proteins involved in mesenchymal proliferation and differentiation. Both EMD and DEX enhanced the expression of amelogenin (amel), and the dentinogenic markers dentin sialophosphoprotein (DSSP) and dentin matrix acidic phosphoprotein 1 (DMP1), as well as the osteogenic markers osteocalcin (OC, BGLAP) and collagen type 1 (COL1A1). Whereas, only EMD had effect on alkaline phosphatase (ALP) mRNA expression, the stimulatory effect were verified by enhanced secretion of OC and COL1A from EMD treated cells, and increased ALP activity in cell culture medium after EMD treatment. Increased levels of interleukin-6 (IL-6), interleukin-8 (IL-8), and monocyte chemoattractant proteins (MCP-1) in the cell culture medium were also found. Consequently, the suggested effect of EMD is to promote differentiation of pulp cells and increases the potential for pulpal mineralization to favor reactive dentine formation.     

Small Structural Differences between Two Ferrocenyl Diphenols Determine Large Discrepancies of Reactivity and Biological Effects

The ferrocenyl diphenol complexes 1,1-bis(4′-hydroxyphenyl)-2-ferrocenyl-but-1-ene ( 1 ) and 1,2-bis(4′-hydroxyphenyl)-1-ferrocenyl-but-1-ene [(Z)- 2 ], which differ by the relative position of the two phenolic substituents, display dramatically different antiproliferative activities on cancer cells ( 1 is far more cytotoxic than 2 ). In this study, our goal was to discover the origin of this difference by comparing their reactivity and biological behaviour. In terms of common behaviour, we found that 1 and 2 are both efficient inhibitors of thioredoxin reductase (TrxR) in vitro after oxidation by a horseradish peroxidase/H₂O₂ system. However, as 1 is only a moderate inhibitor of TrxR in MDA-MB-231 cells, TrxR is probably not the major target responsible for the cytotoxicity of 1 . In terms of differences, we noted that 1 induced a significant redox imbalance characterised by lipid peroxidation and thiol oxidation, and a moderate decrease of the mitochondrial membrane potential in breast cancer cells, whereas 2 has almost no effect. These results underline the importance of the trans configuration in the ferrocenyl–double bond–phenol motif, which is present in 1 but is cis in (Z)- 2 .     

一种新型可编程芯片的应用研究

现场可编程芯片相对ASIC（Application Specific Integrated Circuit）具有设计简单、节省成本、升级容易等许多无可比拟的优点,因此在现代工业中的应用越来越广泛。通过结合在纺织机械自动络筒机中的应用,详细地介绍了一种新型的可编程芯片PSD（Programmable System Devices）,并且对在实际应用中出现的一些问题进行了讨论。     

The effect of surface energy, adsorbed RGD peptides and fibronectin on the attachment and spreading of cells on multiwalled carbon nanotube papers

We report that hydrophilic oxidized multiwalled carbon nanotube papers (CNPs) were efficient substrates for attachment, spreading, and proliferation of MG-63 cells. Complete spreading occurred in the first 4 h of culture even without complete serum or pre-adsorbed adhesion proteins such as collagen or fibronectin. By contrast, the density of adherent cell on hydrophobic CNPs was low. Spreading did not happen after 24 h of culture in absence of serum proteins and growth factors on such papers. Cell viability concomitantly decreased. We also observed that a short RGD peptide, designed to adsorb on both hydrophobic and hydrophilic CNPs, enhanced adhesion, spreading, and proliferation only on hydrophilic CNPs. By contrast, adsorbed fibronectin triggers cell adhesion and spreading on both types of CNPs. Our results show that the imitation of tissue basal membranes with the nanofibrous structure of CNPs is insufficient to trigger the proliferation and spread of cells. Chemical cues are also needed for cells to spread. CNPs, however, offer a better substrate for adhesion protein absorption than do non-porous polymers.     

空间网架螺栓节点球的加工设备研制

本文针对网架螺栓节点球的加工问题，详细阐述了虚拟球心基准加工的思路和数控二坐标回转分度及夹紧的方法，同时介绍了节点球加工中心的总体框架及工作循环，为网架螺栓节点球的加工提供了一种新的工艺方法和高效、高精度的设备。     

高掺量粉煤灰混凝土的性能及其应用

本文介绍高掺量粉煤灰混凝土的性能及其在路面工程中试验性施工 ,试验结果表明 ,常态高掺量粉煤灰混凝土其各项性能指标均接近甚至高于普通混凝土 ,可以在路面工程及其它工程中广泛推广使用     

气动技术在扁平输送带纠偏装置中的应用

本文分析了扁平输送带跑偏的主要原因，介绍了利用气动技术进行扁平输送带纠偏的原理、控制方法及气动纠偏的主要优点。     

板坯连铸机辊子寿命影响因素的分析

本文根据宝钢一炼钢连铸辊的使用维护数据库和生产工艺数据库分析了连铸设备的维护和生产操作对连铸辊使用寿命的影响规律 ,并提出了改进的建议     

Some physico-chemical properties of nine commercial or semi-commercial whey protein concentrates, isolates and fractions

Summary The physico-chemical properties are reported for a group of whey protein powders prepared on a commercial or semi-commercial scale by three companies and chemically characterized as described elsewhere (Holt et al ., 1999). The dependence of the apparent β-lactoglobulin % on the recovered % showed that the nine samples could be placed in three distinct groups with β-lactoglobulin weight % of 70.9 ± 1.1 (Group 1), 62.0 ± 3.4 (Group 2) and 39.5 ± 4.9 (Group 3). Measurements by ¹H-NMR spectroscopy, on 3 of the samples confirmed that the native fold still predominated in the β-lactoglobulin. β-lactoglobulin could be crystallized from all the powders and the normal space group and cell dimensions were determined for the 8 samples that gave crystals of good enough quality for X-ray studies. Differential scanning microcalorimetry of samples dispersed in a phosphate buffer showed a clear difference between Goups 1 and 2 with a more prominent peak due to α-lactalbumin in the Group 2 samples. Light scattering and size exclusion chromatography showed that two types of aggregates were present to a variable extent in all the samples and after a heat treatment, the larger aggregates tended to predominate in Group 2. The rheology measurements, also made in the phosphate buffer, showed a difference of gel stiffness during heat treatment between the Group 1 and Group 2 samples with the exception of the BORCwpc+ sample. Within each group, gel stiffness increased with the degree of lactoslylation of the β-lactoglobulin. Interfacial measurements on samples dispersed in water presented a more complex pattern of behaviour although surface tension measurements at the air water interface of the Group 2 samples showed a two-step pattern of surface tension decrease with time, compared to a single step pattern in the Group 1 samples.     

Binaphthol‐Based Diphosphite Ligands in Asymmetric Nickel‐Catalyzed Hydrocyanation of Styrene and 1,3‐Cyclohexadiene: Influence of Steric Properties

A series of chiral (R)‐binaphthol‐based diphosphite ligands with different substituents was prepared and applied in the asymmetric nickel‐catalyzed hydrocyanation of styrene and 1,3‐cyclohexadiene to investigate the influence of their steric properties. The optimum steric properties for the hydrocyanation reaction lie within a narrow window. With the optimized ligand, hydrocyanation of styrene gave full conversion (Subs/Ni=100) with 49 % ee, the TON was determined to be 600. Hydrocyanation of 1,3‐cyclohexadiene gave 50 % conversion (Subs/Ni=500) with an excellent ee of 86 %. This demonstrates that high ees are not only accessible for vinylarenes but also for conjugated dienes in the asymmetric nickel‐catalyzed hydrocyanation.