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1.
通过实验及热力学分析得出,轧制10B21钢结疤形成主要原因为钢中平均N含量为127×10-6,导致铸坯角部冷却过程中在奥氏体晶界析出细小的BN和AlN夹杂,增加了铸坯的裂纹敏感性,形成铸坯裂纹。通过提高铁水比≥920 kg/t、转炉终点C-T-P(碳-温度-磷)命中率≥85%、出钢口圆流出钢以及LF加热次数≤3次,时间≤25 min等措施可将钢中的氮含量稳定控制在≤50×10-6,有效避免10B21钢轧后盘条结疤,提高成材率,降低成本。  相似文献   
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Bio-ethanol production from algae is a promising way to help solve the energy problem. Alginate is a major component of algae, but it cannot be utilized by existing ethanol fermentation microorganisms. In order to improve the utilization rate of brown algae, high alginate fermentation strains should be obtained. In this research, strains for algae fermentation were got from several experiments. The ethanol yield of strain A was the highest, which was 0.095 g/g (ethanol to alginate). The identification of strain A was carried out and it was 99% identical to Pantoea sp. F16-PCAi-T3P21. Fermentation experiments with different substrates were carried out, such as laminaran, mannitol, L. japonica and acid hydrolysate of L. japonica, and the ethanol yield rate of L. japonica acid hydrolysate was the highest, which reached 0.17 g/g ethanol to L. japonica. It showed that strain A can converse alginate to ethanol in a relatively high yield rate, and might be a promising strain with L. japonica as the substrate, we believe more research should be carried out on this strain.  相似文献   
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目的 探究急性心肌梗死(AMI)患者经皮冠状动脉介入术(PCI)后血清成纤维细胞生长因子21(FGF-21)、髓过氧化物酶(MPO)水平与预后的关系。方法 选择2016年1月至2018年12月在我院接受PCI术治疗的108例AMI患者作为研究对象。根据随访过程中是否发生主要不良心血管事件(MACE),病人分为预后不良组(25例)和预后良好组(83例)。采用酶联免疫吸附法检测受试者血清FGF-21水平,采用胶体金免疫层析法检测受试者血清MPO水平。分析FGF-21、MPO与AMI患者PCI术后MACE发生的关系及诊断MACE发生的效能。结果 预后不良组血清FGF-21、MPO水平均高于预后良好组,差异均有统计学意义(P<0.05)。FGF-21+MPO诊断AMI患者PCI术后MACE发生的ROC曲线下面积(AUC)为0.860,高于FGF-21、MPO单独诊断AMI患者PCI术后MACE发生的AUC。FGF-21>140.41 ng/L和FGF-21≤140.41 ng/L的患者,MACE发生率分别为39.58%和10.00%,差异有统计学意义(P<0.001)。MPO>419.42 μg/L和MPO≤419.42 μg/L的患者,MACE发生率分别为35.00%和8.33%,差异有统计学意义(P=0.001)。Cox单因素及Cox多因素分析显示FGF-21、MPO与AMI患者PCI术后MACE发生密切相关(均P<0.05)。结论 AMI患者PCI术后血清FGF-21、MPO水平与预后有关。高水平的FGF-21、MPO与MACE发生密切相关。  相似文献   
5.
The mammalian cell cycle is important in controlling normal cell proliferation and the development of various diseases. Cell cycle checkpoints are well regulated by both activators and inhibitors to avoid cell growth disorder and cancerogenesis. Cyclin dependent kinase 20 (CDK20) and p21Cip1/Waf1 are widely recognized as key regulators of cell cycle checkpoints controlling cell proliferation/growth and involving in developing multiple cancers. Emerging evidence demonstrates that these two cell cycle regulators also play an essential role in promoting cell survival independent of the cell cycle, particularly in those cells with a limited capability of proliferation, such as cardiomyocytes. These findings bring new insights into understanding cytoprotection in these tissues. Here, we summarize the new progress of the studies on these two molecules in regulating cell cycle/growth, and their new roles in cell survival by inhibiting various cell death mechanisms. We also outline their potential implications in cancerogenesis and protection in heart diseases. This information renews the knowledge in molecular natures and cellular functions of these regulators, leading to a better understanding of the pathogenesis of the associated diseases and the discovery of new therapeutic strategies.  相似文献   
6.
Cassava (Manihot esculanta Crantz) is an important tropical root crop for food security and national economies in Africa. In Ghana, it is the most important staple food also used in breweries, bakery and confectionery industries. Several high-yielding and disease resistant improved cassava varieties (ICVs) have been released and are being promoted through diverse dissemination channels. Past studies investigate the role of information in the adoption of agricultural technologies without accounting for the diversity in the dissemination strategies. The paper explores the diversity of dissemination strategies in examining the adoption of improved cassava varieties using a sequential mixed-method approach which combines exploratory interviews and focus group discussions with a questionnaire-based quantitative survey and the Cragg's two-part model. The paper uses data collected from 608 farmers randomly selected from major cassava producing communities in the Ashanti and Brong-Ahafo regions in Ghana, West Africa. The results show statistically significant and identical impact of information through demonstrations, distribution of planting materials, farmer-to-farmer and media on the probability of ICV adoption. Other drivers of adoption are the membership of farmers based organizations (FBO), planting of two or more varieties and having large livestock size. However, ICV adoption and intensity was hampered by household size, distances to the nearest tarred road and market, and grey-skin color. These attributes need to be integral of dissemination campaigns for cassava variety adoption.  相似文献   
7.
Prostate cancer (PCa) is a reproductive system cancer in elderly men. We investigated the effects of betel nut arecoline on the growth of normal and cancerous prostate cells. Normal RWPE-1 prostate epithelial cells, androgen-independent PC-3 PCa cells, and androgen-dependent LNCaP PCa cells were used. Arecoline inhibited their growth in dose- and time-dependent manners. Arecoline caused RWPE-1 and PC-3 cell cycle arrest in the G2/M phase and LNCaP cell arrest in the G0/G1 phase. In RWPE-1 cells, arecoline increased the expression of cyclin-dependent kinase (CDK)-1, p21, and cyclins B1 and D3, decreased the expression of CDK2, and had no effects on CDK4 and cyclin D1 expression. In PC-3 cells, arecoline decreased CDK1, CDK2, CDK4, p21, p27, and cyclin D1 and D3 protein expression and increased cyclin B1 protein expression. In LNCaP cells, arecoline decreased CDK2, CDK4, and cyclin D1 expression; increased p21, p27, and cyclin D3 expression; had no effects on CDK1 and cyclin B1 expression. The antioxidant N-acetylcysteine blocked the arecoline-induced increase in reactive oxygen species production, decreased cell viability, altered the cell cycle, and changed the cell cycle regulatory protein levels. Thus, arecoline oxidant exerts differential effects on the cell cycle through modulations of regulatory proteins.  相似文献   
8.
为研究车21井区人工裂缝在地层中与天然裂缝沟通情况及裂缝真实展布形态,实现车21井区石炭系裂缝性油藏的经济有效开发,基于地质工程一体化研究思路,在建立储层真三维空间模型基础上,考虑油藏在纵向上岩性的展布和平面属性分布的非均质性,在真三维岩石力学储层中进行压裂裂缝模拟,形成了从地质建模到裂缝模拟的一体化研究流程。结果表明:真三维地质力学模型可真实表征储层岩石力学性质,CHHW2101、CHHW2102井的平均最小水平主应力分别为22.0 MPa和26.0 MPa,与2口井的井底停泵压力23.0 MPa与27.0 MPa相吻合。真三维裂缝模拟技术可更高效、更精准、更直接地对裂缝模拟效果进行评价,判断与天然裂缝连通情况。研究结果可为车21井区后续压裂井提供理论和技术支撑,填补中国国内一体化压裂的空白。  相似文献   
9.
This systematic review study synthesizes research findings pertaining to the use of augmented reality (AR) in language learning. Published research from 2014 to 2019 has been explored and specific inclusion and exclusion criteria have been applied resulting in 54 relevant publications. Our findings determined: (a) devices and software employed for mastering AR; languages and contexts in which AR had been applied; theoretical perspectives adopted for guiding the use of AR; the number of participants in AR activities and benefits from using AR as an educational tool in the language classroom; (b) alignment of the affordances of Augmented Reality with the KSAVE (Knowledge, Skills, Attitudes, Values, Ethics) 21st-century skills framework; (c) future directions in AR research and practice. The main findings from this review demonstrate the popularity of mobile-based AR for supporting vocabulary (23.9%), reading (12.7%), speaking (9.9%) writing (8.5%) or generic language skills (9.9%). Our findings also uncovered areas that merit future attention in the application of AR in language learning – for instance learning theories were not often considered in the implementation of AR. The study concludes with suggestions for future research especially in the areas of instructional design and user experience.  相似文献   
10.
Neurofibromatosis type 1 (NF1) is an autosomal dominant disease caused by mutations in the NF1 tumor suppressor gene, which affect approximately 1 out of 3000 individuals. Patients with NF1 suffer from a range of malignant and nonmalignant manifestations such as plexiform neurofibromas and skeletal abnormalities. We previously demonstrated that Nf1 haploinsufficiency in mesenchymal stem/progenitor cells (MSPCs) results in impaired osteoblastic differentiation, which may be associated with the skeletal manifestations in NF1 patients. Here we sought to further ascertain the role of Nf1 in modulating the migration and adhesion of MSPCs of the Nf1 haploinsufficient (Nf1+/−) mice. Nf1+/− MSPCs demonstrated increased nuclear-cytoplasmic ratio, increased migration, and increased actin polymerization as compared to wild-type (WT) MSPCs. Additionally, Nf1+/− MSPCs were noted to have significantly enhanced cell adhesion to fibronectin with selective affinity for CH271 with an overexpression of its complimentary receptor, CD49e. Nf1+/− MSPCs also showed hyperactivation of phosphoinositide 3-kinase (PI3-K) and mitogen activated protein kinase (MAPK) signaling pathways when compared to WT MSPCs, which were both significantly reduced in the presence of their pharmacologic inhibitors, LY294002 and PD0325901, respectively. Collectively, our study suggests that both PI3-K and MAPK signaling pathways play a significant role in enhanced migration and adhesion of Nf1 haploinsufficient MSPCs.  相似文献   
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