25 research outputs found
Th2 cells are essential for modulation of vascular repair by allogeneic endothelial cells
Get PDFAuthor Manuscript 2011 April 1.Background:
Endothelial cells (ECs) embedded within 3-dimensional matrices (MEEC) control lumenal inflammation and intimal hyperplasia when placed in the vascular adventitia. Matrix embedding alters endothelial immunogenicity in vitro. T-helper (Th) cell-driven host immunity is an impediment of allogeneic grafts. We aimed to identify if modulation of Th balance would affect immune compatibility and endothelial regulation of vascular repair in vivo.
Methods:
Pigs (n = 4/group) underwent carotid artery balloon injury and were left untreated (Group 1) or received perivascular porcine MEEC implants (Group 2), 12 days of cyclosporine A (CsA; Group 3), or MEEC and CsA (Group 4). Host immune reactivity was analyzed after 28 and 90 days.
Results:
MEEC treatment induced formation of EC-specific immunoglobulin (Ig) G1 antibodies (41 ± 6 mean fluorescence intensity [MFI]) and differentiation of host splenocytes into Th2, but not Th1, cytokine-producing cells (interleukin [IL]-4, 242 ± 102; IL-10, 273 ± 114 number of spots). Concomitant CsA therapy reduced IgG1 antibody frequency (25 ± 2 MFI; p < 0.02) and Th2-cytokine producing splenocytes upon MEEC treatment (IL-4, 157 ± 19; IL-10, 124 ± 26 number of spots; p < 0.05). MEECs inhibited luminal occlusion 28 and 90 days after balloon injury (12 ± 7%) vs untreated controls (68 ± 14%; p < 0.001) but to a lesser extent with concomitant CsA treatment (34 ± 13%; p < 0.02 vs Group 2).
Conclusions:
MEECs do not induce a significant Th1-driven immune response but do enhance differentiation of splenocytes into cells producing Th2 cytokine. Reduction in this Th2 response reduces the vasoregulatory effects of allogeneic ECs after injury
The influence of technology and demand factors on firm size and industrial structure in the DRAM market -- 1973-1988
Get PDFThe focus of this research is on the impact of the diffusion of innovations in integrated circuit technology on the market structure of that industry and the implications of firm strategy for both further innovation and market structure change. The study examines the effects of sustained product innovation over a fifteen-year-period in the DRAM segment of the integrated circuit industry. Assessments are made on first mover advantages, shape of the diffusion curve, and resource needs in a market characterized by an increasingly complex technology. Comparisons are made along the dimensions of number of firms in the market, continuity of the firms and market concentration.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/30210/1/0000600.pd
The influence of technology and demand factors on firm size and industrial structure in the DRAM market -- 1973-1988
No full textTechnological Innovations and Consumer Needs: An Analysis of Mobile Communications Market
No full textThis study combines insights from market diffusion and consumer research to provide an inte-grated framework of mobile communications market in Japan. We base our analysis on data from company interview, focus group discussion and industry reports. Our findings indicate that technology push dominates in the early introduction and consumer needs pull in the maturing stage. Three implications for the marketing area are; first, user needs for mobile communications have evolved from basic mobility and functionality to include aesthetic and experiential benefits, second, innovations of product capabilities co-evolve with user needs, and lead to increases in mobile usage and product-user attachments, and third, in a saturated market, mobile consumption is premised on the utilitarian and hedonic values as perceived by the users. As mobile phone is a universal product, analysis of a saturated market such as Japan provides a deeper understanding of the evolution of technology and consumer in other markets
Technological Innovations and Consumer Needs: An Analysis of Mobile Communications Market
Get PDFTechnology, consumer needs, mobile communication, Japa
Market- and committee-based mechanisms in the creation and diffusion of global industry standards: the case of mobile communication
No full text
The grand coalition versus competing coalitions: trade-offs in how to standardize
Get PDFThe standardization landscape in the Information and Communication technology industries is fragmented in many different standardization bodies, industry consortia, and alliances. Some of these coalitions cooperate with each other, while others compete. The existence of competing standardization coalitions may prevent coordination on a common standard. There is a lot of debate among practitioners and analysts about whether this fragmentation creates a coordination failure. This paper takes a middle ground in this debate. Competition between standardization coalitions may indeed harm compatibility, but it also helps to mitigate coordination failures within standardization bodies and coalitions. The negotiation process in a coalition can cause coordination failures of its own. An important failure is lack of timeliness, due to delaying tactics by company delegates in the coalition. Introducing competition between coalitions can speed up negotiations within them, and thus help to overcome this intracommittee coordination failure. A game theoretic model explores the effect of competition between coalitions on the speed of decision-making and standardization.Economics ;
Technological Innovations and Consumer Needs: An Analysis of Mobile Communications Market
No full textThis study combines insights from market diffusion and consumer research to provide an inte-grated framework of mobile communications market in Japan. We base our analysis on data from company interview, focus group discussion and industry reports. Our findings indicate that technology push dominates in the early introduction and consumer needs pull in the maturing stage. Three implications for the marketing area are; first, user needs for mobile communications have evolved from basic mobility and functionality to include aesthetic and experiential benefits, second, innovations of product capabilities co-evolve with user needs, and lead to increases in mobile usage and product-user attachments, and third, in a saturated market, mobile consumption is premised on the utilitarian and hedonic values as perceived by the users. As mobile phone is a universal product, analysis of a saturated market such as Japan provides a deeper understanding of the evolution of technology and consumer in other markets.Keywords: Technology, consumer needs, mobile communication, Japa
Removing noise from pyrosequenced amplicons
Get PDF<b>Background</b><p></p>
In many environmental genomics applications a homologous region of DNA from a diverse sample is first amplified by PCR and then sequenced. The next generation sequencing technology, 454 pyrosequencing, has allowed much larger read numbers from PCR amplicons than ever before. This has revolutionised the study of microbial diversity as it is now possible to sequence a substantial fraction of the 16S rRNA genes in a community. However, there is a growing realisation that because of the large read numbers and the lack of consensus sequences it is vital to distinguish noise from true sequence diversity in this data. Otherwise this leads to inflated estimates of the number of types or operational taxonomic units (OTUs) present. Three sources of error are important: sequencing error, PCR single base substitutions and PCR chimeras. We present AmpliconNoise, a development of the PyroNoise algorithm that is capable of separately removing 454 sequencing errors and PCR single base errors. We also introduce a novel chimera removal program, Perseus, that exploits the sequence abundances associated with pyrosequencing data. We use data sets where samples of known diversity have been amplified and sequenced to quantify the effect of each of the sources of error on OTU inflation and to validate these algorithms. <p></p>
<b>Results</b><p></p>
AmpliconNoise outperforms alternative algorithms substantially reducing per base error rates for both the GS FLX and latest Titanium protocol. All three sources of error lead to inflation of diversity estimates. In particular, chimera formation has a hitherto unrealised importance which varies according to amplification protocol. We show that AmpliconNoise allows accurate estimates of OTU number. Just as importantly AmpliconNoise generates the right OTUs even at low sequence differences. We demonstrate that Perseus has very high sensitivity, able to find 99% of chimeras, which is critical when these are present at high frequencies. <p></p>
<b>Conclusions</b><p></p>
AmpliconNoise followed by Perseus is a very effective pipeline for the removal of noise. In addition the principles behind the algorithms, the inference of true sequences using Expectation-Maximization (EM), and the treatment of chimera detection as a classification or 'supervised learning' problem, will be equally applicable to new sequencing technologies as they appear.<p></p>
