The N- and C-terminal domains of parathyroid hormone-related protein affect differently the osteogenic and adipogenic potential of human mesenchymal stem cells

Parathyroid hormone-related protein (PTHrP) is synthesized by diverse tissues, and its processing produces several fragments, each with apparently distinct autocrine and paracrine bioactivities. In bone, PTHrP appears to modulate bone formation in part through promoting osteoblast differentiation. The putative effect of PTH-like and PTH-unrelated fragments of PTHrP on human mesenchymal stem cell (MSCs) is not well known. Human MSCs were treated with PTHrP (1-36) or PTHrP (107-139) or both (each at 10 nM) in osteogenic or adipogenic medium, from the start or after 6 days of exposure to the corresponding medium, and the expression of several osteoblastogenic and adipogenic markers was analyzed. PTHrP (1-36) inhibited adipogenesis in MSCs and favoured the expression of osteogenic early markers. The opposite was observed with treatment of MSCs with PTHrP (107-139). Moreover, inhibition of the adipogenic differentiation by PTHrP (1-36) prevailed in the presence of PTHrP (107-139). The PTH/PTHrP type 1 receptor (PTH1R) gene expression was maximum in the earlier and later stages of osteogenesis and adipogenesis, respectively. While PTHrP (107-139) did not modify the PTH1R overexpression during adipogenesis, PTHrP (1-36) did inhibit it; an effect which was partially affected by PTHrP (7-34), a PTH1R antagonist, at 1 µM. These findings demonstrate that both PTHrP domains can exert varying effects on human MSCs differentiation. PTHrP (107-139) showed a tendency to favor adipogenesis, while PTHrP (1-36) induced a mild osteogenic effect in these cells, and inhibited their adipocytic commitment. This further supports the potential anabolic action of the latter peptide in humans.     

草地早熟禾在成都市的栽培与应用

根据成都市的气候特点及草地早熟禾的生物特性，介绍它在成都市的栽培管理技术及应用范围．     

裸燕麦永红492栽培种(Avena nuda cv.yong hong 492)的体细胞胚胎发生

以裸燕麦永红492栽培种的三个发育时期的茎尖为外植体,研究发育时期、基本培养基组成(MS,B5,N6)、激素、肌醇、含氮化合物及渗透势对体细胞胚胎发生及小植株分化的影响。发现营养生长锥时期是体细胞胚胎发生最好的实验材料;2,4-D是诱导愈伤组织必不可少的因素,6—BA对体细胞胚胎发生没什么影响;往培养基中加入适量的肌醇和含氮化合物以及适当地降低培养基的渗透势均有利于体细胞胚胎发生及小植株形成。在液体培养中,发现培养基中古有2,4-D比无2,4-D更有利于胚状体发生     

近半个世纪以来中国季风区气温与降水变化及其时空差异

利用中国东部季风区20个测站1960-2012年气温和降水量的月值数据,采用线性趋势分析、Mann-Kendall突变检验、Morlet小波分析等方法,分析了季风区各区域年平均气温和年降水量的变化趋势、突变现象和周期特征.结果表明1960-2012年季风区各区域均有增温趋势,在20世纪90年代发生突变,东北地区发生突变要早于其他地区,北方地区的增温幅度大于南方,存在4年左右周期,8～16年的准周期,气温的高频变化周期在内陆地区表现更为明显;年降水量在53年里处于波动状态,四川盆地、华北地区和季风区西北部地区降水有减少趋势,长江流域下游降水有增加趋势,其他地区没有明显变化趋势,存在2～4年周期、8～16年左右准周期,降水的低频变化周期在近海地区表现更为明显.     

Numerical simulation of Mach reflections

In this paper, the “FLIC” difference method with triangular mesh is adopted to numerically simulate the regular and Mach reflections that occur when a shock wave pass around a wedge. The compuational result is compared with the shock tube experimental results of G. Ben-Dor and I. I. Glass. The comparison shows that the position, shape of shock wave and height of Mach stem all show a good agreement. Consequently, the “FLIC” difference method with triangular mesh is quite satisfactory in numerical simulation of the regular and Mach reflections.     

广西白蜡生产失败原因剖析

广西白蜡生产失败的主要原因是，首先，年降雨量超过１５５２ｍｍ，间接或直接地引起大批白蜡虫死亡；其次，对白蜡虫具有毁灭性的白蜡虫寄生蜂不采取任何防治措施，致使种虫寄生率高达９２．９％。因此，白蜡生产遭受失败。广西气候多种多样，年降雨量、在１５５２ｍｍ以下有２２个县，发展白蜡生产是有潜力的，可逐步恢复和发展白蜡生产。     

企业设备年检档案的收集与管理

论述了设备大检修档案在企业生产改、扩建中所起到的作用,介绍了设备大检修档案的收集范围,探讨了管理年度设备大检修档案的对策。     

High‐Throughput,Label‐Free Isolation of Cancer Stem Cells on the Basis of Cell Adhesion Capacity

Herein we report a microfluidics method that enriches cancer stem cells (CSCs) or tumor‐initiating cells on the basis of cell adhesion properties. In our on‐chip enrichment system, cancer cells were driven by hydrodynamic forces to flow through microchannels coated with basement membrane extract. Highly adhesive cells were captured by the functionalized microchannels, and less adhesive cells were collected from the outlets. Two heterogeneous breast cancer cell lines (SUM‐149 and SUM‐159) were successfully separated into enriched subpopulations according to their adhesive capacity, and the enrichment of the cancer stem cells was confirmed by flow cytometry biomarker analysis and tumor‐formation assays. Our findings show that the less adhesive phenotype is associated with a higher percentage of CSCs, higher cancer‐cell motility, and higher resistance to chemotherapeutic drugs.     

Strand displacement amplification for ultrasensitive detection of human pluripotent stem cells

Human pluripotent stem cells (hPSCs), such as embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs), provide a powerful model system for studies of cellular identity and early mammalian development, which hold great promise for regenerative medicine. It is necessary to develop a convenient method to discriminate hPSCs from other cells in clinics and basic research. Herein, a simple and reliable biosensor for stem cell detection was established. In this biosensor system, stage-specific embryonic antigen-3 (SSEA-3) and stage-specific embryonic antigen-4 (SSEA-4) were used to mark human pluripotent stem cells (hPSCs). Antibody specific for SSEA-3 was coated onto magnetic beads for hPSCs enrichment, and antibody specific for SSEA-4 was conjugated with carboxyl-modified tDNA sequence which was used as template for strand displacement amplification (SDA). The amplified single strand DNA (ssDNA) was detected with a lateral flow biosensor (LFB). This biosensor is capable of detecting a minimum of 19 human embryonic stem cells by a strip reader and 100 human embryonic stem cells by the naked eye within 80 min. This approach has also shown excellent specificity to distinguish hPSCs from other types of cells, showing that it is promising for specific and handy detection of human pluripotent stem cells.     

Aligned Poly(ε‐caprolactone) Nanofibers Guide the Orientation and Migration of Human Pluripotent Stem Cell‐Derived Neurons,Astrocytes, and Oligodendrocyte Precursor Cells In Vitro

Stem cell transplantations for spinal cord injury (SCI) have been studied extensively for the past decade in order to replace the damaged tissue with human pluripotent stem cell (hPSC)‐derived neural cells. Transplanted cells may, however, benefit from supporting and guiding structures or scaffolds in order to remain viable and integrate into the host tissue. Biomaterials can be used as supporting scaffolds, as they mimic the characteristics of the natural cellular environment. In this study, hPSC‐derived neurons, astrocytes, and oligodendrocyte precursor cells (OPCs) are cultured on aligned poly(ε‐caprolactone) nanofiber platforms, which guide cell orientation to resemble that of spinal cord in vivo. All cell types are shown to efficiently spread over the nanofiber platform and orient according to the fiber alignment. Human neurons and astrocytes require extracellular matrix molecule coating for the nanofibers, but OPCs grow on nanofibers without additional treatment. Furthermore, the nanofiber platform is combined with a 3D hydrogel scaffold with controlled thickness, and nanofiber‐mediated orientation of hPSC‐derived neurons is also demonstrated in a 3D environment. In this work, clinically relevant materials and substrates for nanofibers, fiber coatings, and hydrogel scaffolds are used and combined with cells suitable for developing functional cell grafts for SCI repair.