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排序方式: 共有173条查询结果,搜索用时 12 毫秒
1.
Peer-assisted learning interventions with elementary school students: A meta-analytic review. 总被引:1,自引:0,他引:1
Rohrbeck Cynthia A.; Ginsburg-Block Marika D.; Fantuzzo John W.; Miller Traci R. 《Canadian Metallurgical Quarterly》2003,95(2):240
A meta-analytic review of group comparison design studies evaluating peer-assisted learning (PAL) interventions with elementary school students produced positive effect sizes (ESs) indicating increases in achievement (unweighted mean ES = 0.59, SD = 0.90; weighted ES, d = 0.33, p 相似文献
2.
Marika Lüders Asbjørn Følstad Espen Waldal 《Journal of Computer-Mediated Communication》2014,19(3):446-462
Social media are often argued to change political communication, decreasing the distance between politicians and citizens, and increasing citizens' influence on policymaking. This paper presents findings from a study of how the Norwegian Labour Party uses social media, focusing on the community platform MyLabourParty. Interviews with politicians and a survey with citizens as respondents were conducted to examine the experiences of online political discussions. Findings show that citizens and politicians expect MyLabourParty to strengthen citizen participation. Yet, citizens still experience communication asymmetry and politicians may find it challenging to participate to the extent citizens expect. Means for bridging the gap between expectations and experiences are called for, in particular redefinition of the offering, changes of user‐practices, and system improvements. 相似文献
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Benedetta Mattorre Silvana Caristi Simona Donato Emilia Volpe Marika Faiella Alessandro Paiardini Rosa Sorrentino Fabiana Paladini 《International journal of molecular sciences》2022,23(9)
The M1 zinc metalloproteases ERAP1, ERAP2, and IRAP play a role in HLA-I antigen presentation by refining the peptidome either in the ER (ERAP1 and ERAP2) or in the endosomes (IRAP). They have also been entrusted with other, although less defined, functions such as the regulation of the angiotensin system and blood pressure. In humans, ERAP1 and IRAP are commonly expressed. ERAP2 instead has evolved under balancing selection that maintains two haplotypes, one of which undergoing RNA splicing leading to nonsense-mediated decay and loss of protein. Hence, likewise in rodents, wherein the ERAP2 gene is missing, about a quarter of the human population does not express ERAP2. We report here that macrophages, but not monocytes or other mononuclear blood cells, express and secrete an ERAP2 shorter form independent of the haplotype. The generation of this “short” ERAP2 is due to an autocatalytic cleavage within a distinctive structural motif and requires an acidic micro-environment. Remarkably, ERAP2 “short” binds IRAP and the two molecules are co-expressed in the endosomes as well as in the cell membrane. Of note, the same phenomenon could be observed in some cancer cells. These data prompt us to reconsider the role of ERAP2, which might have been maintained in humans due to fulfilling a relevant function in its “short” form. 相似文献
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Marika Lanza Alessia Filippone Giovanna Casili Letterio Giuffr Sarah Adriana Scuderi Irene Paterniti Michela Campolo Salvatore Cuzzocrea Emanuela Esposito 《International journal of molecular sciences》2022,23(9)
Migraine is a common brain-disorder that affects 15% of the population. Converging evidence shows that migraine is associated with gastrointestinal disorders. However, the mechanisms underlying the interaction between the gut and brain in patients with migraine are not clear. In this study, we evaluated the role of the short-chain fatty acids (SCFAs) as sodium propionate (SP) and sodium butyrate (SB) on microbiota profile and intestinal permeability in a mouse model of migraine induced by nitroglycerine (NTG). The mice were orally administered SB and SP at the dose of 10, 30 and 100 mg/kg, 5 min after NTG intraperitoneal injections. Behavioral tests were used to evaluate migraine-like pain. Histological and molecular analyses were performed on the intestine. The composition of the intestinal microbiota was extracted from frozen fecal samples and sequenced with an Illumina MiSeq System. Our results demonstrated that the SP and SB treatments attenuated hyperalgesia and pain following NTG injection. Moreover, SP and SB reduced histological damage in the intestine and restored intestinal permeability and the intestinal microbiota profile. These results provide corroborating evidence that SB and SP exert a protective effect on central sensitization induced by NTG through a modulation of intestinal microbiota, suggesting the potential application of SCFAs as novel supportive therapies for intestinal disfunction associated with migraine. 相似文献
6.
Marika Jestoi Talvikki Järvinen Eila Järvenpää Heli Tapanainen Suvi Virtanen Kimmo Peltonen 《Food chemistry》2009
A method applying solid-phase microextraction followed by gas chromatography–mass spectrometric determination was in-house validated and used to study furan concentrations in baby-food samples purchased from the Finnish markets. The validation parameters showed that the method was well applicable for the reliable analysis of furan. Furan was analysed in 21 different baby-food samples as three independent replicates. The mean levels of furan varied between 4.7 and 90.3 μg kg−1 being well in accordance with the levels reported in other studies. The mean concentrations of similar product formulas based on their ingredients were 9.2, 37.0 and 49.6 μg kg−1 for fruit-, vegetables- and meat-containing baby-foods, respectively. According to the statistical analyses, fruit-based baby-food samples had significantly lower concentrations of furan as compared to other formulas. Based on our exercise, it seems that a low margin of safety exists between the extreme worst case infant exposures and the deduced NOAEL of furan on experimental animals, particularly for a clear rodent carcinogen. 相似文献
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Jestoi M Somma MC Kouva M Veijalainen P Rizzo A Ritieni A Peltonen K 《Molecular nutrition & food research》2004,48(4):299-307
The contamination levels of 16 different Fusarium- and Aspergillus-mycotoxins were chemically determined from randomly selected organic and conventional grain-based products purchased from Finnish and Italian markets. The cytotoxicity of the samples was analyzed with an in vitro test using feline fetal lung cells. Overall, the concentrations of the mycotoxins studied were low in all of the samples. Enniatins B and B1 as well as deoxynivalenol were the most predominant mycotoxins in the samples, being present in 97%, 97%, and 90% of the samples, respectively. The geographical origin or the agricultural practice had no influence on the mycotoxin concentrations of the samples. The babyfoods included in the samples had significantly lower concentrations of mycotoxins than the other products with a mean total mycotoxin content of 47 microg/kg compared with 99 microg/kg for the other kinds of food. All the samples evoked toxicity in the in vitro test, but no correlation between cytotoxicity and the mycotoxin concentrations was observed. 相似文献
9.
The influence of silver loading on the lean NOx reduction activity using methanol as reductant has been studied for alumina supported silver catalysts. In general, increasing the silver loading (0–3 wt%), in Ag–Al2O3, shifts or extends the activity window, for lean NOx reduction towards lower temperatures. In particular Ag–Al2O3 with 3 wt% silver is active for NOx reduction under methanol-SCR conditions in a broad temperature interval (200–500 °C), with high activity in the low temperature range (maximum around 300 °C) typical for exhaust gases from diesel and other lean burn engines. Furthermore, increasing the C/N molar ratio enhances the reduction of NOx. However, too high C/N ratios results in poor selectivity to N2. 相似文献
10.
Maria Jonstrup Marika Murto Bo Mattiasson 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2013,88(3):388-394
BACKGROUND: Phanerochaete chrysosporium, Trametes versicolor and Bjerkandera sp BOL13 were compared for decolorization of azo dyes supplied individually or as a mixture. The dye decolorization was also evaluated during continuous treatment under non‐sterile conditions using a lignocellulosic growth substrate. RESULTS: Bjerkandera sp BOL13 showed the highest dye decolorization potential. This fungus was also found to support high decolorization of Remazol Red RR at an initial pH of 4‐6 and when using straw as co‐substrate. The fungus was evaluated for Remazol Red RR decolorization in a continuously fed packed‐bed bioreactor operated under non‐sterile conditions with 3 days of hydraulic retention time. When glucose was supplied as growth‐substrate, decolorization efficiencies of 65‐90% were maintained for 12 days in a bioreactor packed with wooden material. The decolorization efficiency was lower when glucose was not fed to the fungus or when a plastic material was used as packing. Higher manganese peroxidase and laccase activities were also recorded when the wood packing was used. Contamination caused a drop in decolorization efficiency after 17‐19 days operation. CONCLUSIONS: The potential of Bjerkandera sp BOL13 for decolorization of azo dyes under non‐sterile conditions using lignocellulosic growth substrates was demonstrated. Research is needed to reduce contamination under non‐sterile conditions. © 2012 Society of Chemical Industry 相似文献