Involvement of endothelial progenitor cells in the formation of plexiform lesions in broiler chickens: possible role of local immune/inflammatory response

Plexiform lesions (PLs), which are often accompanied by perivascular infiltrates of mononuclear cells, represent the hallmark lesions of pulmonary arteries in humans suffering from severe pulmonary arterial hypertension (PAH). Endothelial progenitor cells (EPCs) have been recently implicated in the formation of PLs in human patients. PLs rarely develop in rodent animal models of PAH but can develop spontaneously in broiler chickens. The aim of the present study was to confirm the presence of EPCs in the PLs in broilers. The immune mechanisms involved in EPC dysfunction were also evaluated. Lungs were collected from commercial broilers at 1 to 4 weeks of age. The right/total ventricle ratios indicated normal pulmonary arterial pressures for all sampled birds. Immunohistochemistry was performed to determine the expressions of EPC markers (CD133 and VEGFR-2) and proangiogenic molecule hepatocyte growth factor (HGF) in the lung samples. An EPC/lymphocyte co-culture system was used to investigate the functional changes of EPCs under the challenge of immune cells. PLs with different cellular composition were detected in the lungs of broilers regardless of age, and they were commonly surrounded by moderate to dense perivascular mononuclear cell infiltrates. Immunohistochemical analyses revealed the presence of CD133⁺ and VEGFR-2⁺ cells in PLs. These structures also exhibited a strong expression of HGF. Lymphocyte co-culture enhanced EPC apoptosis and completely blocked HGF-stimulated EPC survival and in vitro tube formation. Taken together, this work provides evidence for the involvement of EPCs in the development of PLs in broilers. It is suggested that the local immune cell infiltrate might serve as a contributor to EPC dysfunction by inducing EPC death and limiting their response to angiogenic stimuli. Broiler chickens may be valuable for investigating reversibility of plexogenic arteriopathy using genemodified inflammation-resistant EPCs.     

The Role of School Climate in Explaining Changes in Social Trust Over Time

School is often ranked highly among social agents that are central to the development of various citizenship values and norms in younger members of society. In this paper, we examined the impact of two dimensions of school climate on changes in social trust among adolescents over time, namely relationships and safety. Using a series of latent change models on 3-wave panel data concerning roughly 850 Swedish adolescents aged 16 to 18 years, we found that experiences of victimization in school mattered most in predicting changes in social trust across 3 time points, when relevant demographic factors and other aspects of the school climate were controlled. In particular, social trust declined most among adolescents who experienced more victimization at school.     

定量分析能源效率以及温室气体减排项目和政策中的协同效益方面的国际经验

提高能效和燃料转换效率是温室气体减排战略的一部分。过去二十年,很多研究显示这两方面带来气候变化以外的好处,多半介于这些政策方案实施成本的30%到超过100%。国际上,政策制定者对于分析能效政策和燃料转换效率政策同时纳入对温室气体和非温室气体两方面影响的探讨愈来愈感兴趣。欧盟、美国与日本已开发出一套相当成熟的方法。通常,协同效益的定量工作可分为三类:(1)协同效益模型;(2)事前的政策评估方法;(3)由学者建立的框架,意在改善这方面的研究,并将协同效益应用到更多的地区和政策方案上。 表ES-1将协同效益定量方面的几个重点模型、指南和框架做了摘要。     

Extraction of DNA suitable for PCR applications from mature leaves of Mangifera indica L.

Good quality deoxyribonucleic acid (DNA) is the pre-requisite for its downstream applications. The presence of high concentrations of polysaccharides, polyphenols, proteins, and other secondary me- tabolites in mango leaves poses problem in getting good quality DNA fit for polymerase chain reaction (PCR) applications. The problem is exacerbated when DNA is extracted from mature mango leaves. A reliable and modified protocol based on the cetyl- trimethylammonium bromide (CTAB) method for DNA extraction from mature mango leaves is described here. High concentrations of inert salt were used to remove polysaccharides; Polyvinylpyrrolidone (PVP) and β-mercaptoethanol were employed to manage phenolic compounds. Extended chloroform-isoamyl alcohol treatment followed by RNase treatment yielded 950?1050 μg of good quality DNA, free of protein and RNA. The problems of DNA degradation,contamination, and low yield due to irreversible binding of phenolic compounds and coprecipitation of polysaccharides with DNA were avoided by this method. The DNA isolated by the modified method showed good PCR amplification using simple se- quence repeat (SSR) primers. This modified protocol can also be used to extract DNA from other woody plants having similar problems.     

Integrating technology in English language teaching through a community of practice in the Sultanate of Oman: implications for policy implementation

Educational Research for Policy and Practice - Much has been written, published, and presented about the important role and uses of technology in English language teaching (ELT) today and the...     

The effects of perceived parental math support on middle school students’ math engagement: the serial multiple mediation of math self-efficacy and math enjoyment

The present study explored the direct and indirect (serial multiple mediation of math self-efficacy and math enjoyment) effects of perceived parental math support on middle school students’ math engagement. A total of 374 middle school students ranging the age of 11 to 15 years completed a set of questionnaires assessing perceived parental math support, math self-efficacy, math enjoyment, and math engagement. In the analysis of structural model, a multiple-step multiple mediation analysis was employed. The findings indicated that perceived parental math support was directly and positively associated with math engagement. Additionally, math self-efficacy and math enjoyment sequentially mediated the relationship between parental math support and math engagement. The limitations and implications of the results are discussed and suggestions for future research are proposed.