Microfluidic model of monocyte extravasation reveals the role of hemodynamics and subendothelial matrix mechanics in regulating endothelial integrity     

Sandra Prez-Rodríguez  Stephanie A. Huang  Carlos Borau  Jos Manuel García-Aznar  William J. Polacheck 《Biomicrofluidics》2021,15(5)

Extravasation of circulating cells is an essential process that governs tissue inflammation and the body''s response to pathogenic infection. To initiate anti-inflammatory and phagocytic functions within tissues, immune cells must cross the vascular endothelial barrier from the vessel lumen to the subluminal extracellular matrix. In this work, we present a microfluidic approach that enables the recreation of a three-dimensional, perfused endothelial vessel formed by human endothelial cells embedded within a collagen-rich matrix. Monocytes are introduced into the vessel perfusate, and we investigate the role of luminal flow and collagen concentration on extravasation. In vessels conditioned with the flow, increased monocyte adhesion to the vascular wall was observed, though fewer monocytes extravasated to the collagen hydrogel. Our results suggest that the lower rates of extravasation are due to the increased vessel integrity and reduced permeability of the endothelial monolayer. We further demonstrate that vascular permeability is a function of collagen hydrogel mass concentration, with increased collagen concentrations leading to elevated vascular permeability and increased extravasation. Collectively, our results demonstrate that extravasation of monocytes is highly regulated by the structural integrity of the endothelial monolayer. The microfluidic approach developed here allows for the dissection of the relative contributions of these cues to further understand the key governing processes that regulate circulating cell extravasation and inflammation.  相似文献   

Robust observer design by sign-stability for the monitoring of population systems     

Inmaculada López  María Luz Puertas  Carmelo Rodríguez  Manuel Gámez  Zoltán Varga 《Journal of The Franklin Institute》2019,356(4):2240-2257

Monitoring problem in population ecology can be formalized as observer design for the population system in question: Supposing that we observe only certain species considered indicators, we want to recover or estimate the whole state process of the population system, where the state vector is usually composed from the biomasses of the single populations. In the present paper, for stably coexisting population systems, a new approach to the design of the corresponding observer system is proposed which, from the knowledge of the observed indicator(s), estimates the state process with exponential convergence. In the usual observer design, an auxiliary matrix, the so-called gain matrix must be found that guarantees the mentioned exponential convergence. The novelty is in that due to the required sign-stability (or qualitative stability) of the interaction pattern, the designed observer system (i.e. the gain matrix) is robust against quantitative changes in the inter- and intra-specific interactions. (Here the interaction pattern is described by a matrix having the signs as entries, indicating the quality of the interactions within and between the considered species.) In other words, under sign-stability conditions, in the observer design the same gain matrix can be used even if, due to environmental changes, the intensities of certain interactions suffer a quantitative change in the meanwhile. The requirement of sign-stability of the interaction pattern can be considered rather natural, since in a stably coexisting population system, it means for example that a predator–prey relation does not change into a prey–predator interaction, and interactions neither appear nor disappear within the system. Our approach to robust observer design is illustrated on model population systems, such as trophic chains of type resource-producer-primary consumer-secondary consumer and Lotka–Volterra system with vertical structure. For the latter system a Lyapunov function is also constructed that guarantees the global asymptotic stability of the positive equilibrium of the considered model.  相似文献   

Still life with rhetoric: A new materialist approach for visual rhetorics. L. E. Gries. Boulder,CO: University Press of Colorado, 2015, 324 pages,including index. US$27.95 (paperback).     

Manuel Pina 《Technical Communication Quarterly》2018,27(2):198-200

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Market size and innovation: The intermediary role of technology licensing     

Manuel Hermosilla  Yufei Wu 《Research Policy》2018,47(5):980-991

Previous literature finds that larger downstream markets fuel the innovation of new technologies by incentivizing firms to spend more on R&D. Our evidence shows that larger markets also increase the extent of licensing-based cooperation between upstream innovators and downstream commercializers. This cooperation is valuable because it pools firms’ complementary capabilities. Thus, downstream market expansions could positively impact innovative outcomes even holding R&D expenditures constant. Evidence is drawn from the drug candidate licensing market, exploiting the quasi-experimental variation introduced by the enactment of the Medicare Part D program in 2003. A model for the determination of equilibrium commercialization strategies in Markets for Technology rationalizes our finding. In this framework, cooperation gains are proportional to market size but transaction costs are not. Thus, larger downstream markets foster cooperation by reducing the relative importance of the latter. To better match the empirical context, the model extends the canonical “one technology–one application” framework of related work, to the more general case of “composite technologies,” which may have more than one end-user application.  相似文献   

Developmental Trends in Flexibility and Automaticity of Social Cognition          下载免费PDF全文

Elizabeth O. Hayward  Bruce D. Homer  Manuel Sprung 《Child development》2018,89(3):914-928

Age‐related changes in flexibility and automaticity of reasoning about social situations were investigated. Children (N = 101; age range = 7;8–17;7) were presented with the flexibility and automaticity of social cognition (FASC), a new measure of social cognition in which cartoon vignettes of social situations are presented and participants explain what is happening and why. Scenarios vary on whether the scenario is socially ambiguous and whether or not language is used. Flexibility is determined by the number of unique, plausible explanations, and automaticity is indicated by speed of response. Overall, both flexibility and automaticity increased significantly with age. Language and social ambiguity influenced performance. Future work should investigate differences in FASC in older populations and clinical groups.  相似文献   

Attitudes to innovation in peripheral economic regions     

Daniel Coronado  Manuel Acosta  Ana Fernndez 《Research Policy》2008,37(6-7):1009-1021

The objective of this study is to shed light on the identification of the internal and external factors that affect the attitudes towards innovation of companies located in regions situated on the periphery of economic centres. The main research questions are as follows: (1) What are the internal factors that predispose companies to seek access to innovation? (2) To what extent do external factors such as location and technological opportunities condition or stimulate favourable attitudes towards innovation? To test the hypotheses put forward to answer these questions, we formulate and estimate econometric specifications, taking a sample of more than 2000 companies situated in Andalusia (one of the less-favoured regions in Spain). Our results show that the cost of innovation and the level of indebtedness of a company have a statistically significant and negative effect on attitudes to innovation, whereas the technical qualifications of the employees, the propensity to export, and the company size (measured by the number of employees) have a significant and positive effect on a company's attitude towards innovation. Furthermore, technological opportunities and location exert positive effects on attitudes towards innovation.  相似文献   

Modeling educational choices. A binomial logit model applied to the demand for Higher Education   总被引：2，自引：0，他引：2  

Juan de Dios Jiménez  Manuel Salas-Velasco 《Higher Education》2000,40(3):293-311

This paper presents a microeconomic analysis of the choice of universitydegree course that individuals make on finishing their Secondary studies(four-year university degree or three-year university degree), andcontains the theoretical framework as well as empirical results. Themodel selected for our analysis is a binomial logit model. This model,which can be seen as a special case of a general model of utilitymaximization, deals with those aspects of the economics of educationalchoice that are regarded as important in the literature of this subject:academic aptitude, the social background in which the students havegrown up, family income, employment prospects, etc. By using survey dataon educational choices of Spanish High School graduates (cross-sectionaldata), we investigate to what extent the theoretical determinants areconfirmed in practice. The results of the estimation by maximumlikelihood of the logit model, and which allow us to analyze theinfluence of the explanatory variables on the probability of choosing afour-year university degree, show how social background, family earningsand scholastic ability explain, mainly, the educational choice ofstudents. The students from higher socioeconomic status as well as thosewith the best High School curricula are more likely to follow auniversity degree of greater duration.  相似文献   

Identification of drug-resistantMycobacterium tuberculosis by single strand conformation polymorphism and cleavase fragment length polymorphism     

Manju Sharma  Manuel Altamirano 《Indian journal of clinical biochemistry : IJCB》2000,15(2):88-93

Twenty isolates ofMycobacterium tuberculosis resistant to rifampicin(RIF), isoniazid(INH) and streptomycin(STR) were analysed by Polymerase Chain Reaction (PCR) amplification of rpoB, katG and rrs genes to evaluate comparative diagnostic significance of genetic assays. Mutations were identified by single strand conformation polymorphism (SSCP) and cleavase fragment length polymorphism (CFLP) and were confirmed by DNA sequencing. SSCP of 4 RIF resistant and 14 INH resistant isolates showed an extra peak at the level of 75-bp and 85-bp respectively, while 2 STR resistant isolates showed 2 peaks with 9 bases difference. CFLP showed a different pattern among RIF, INH and STR sensitive and resistant isolates Thus SSCP and CFLP can be used as alternative diagnostic methods for identification of mutations in RIF, INH and STR resistant strains of M.tuberculosis.  相似文献   

Colorimetric Evaluation of Pictorial Coatings in Conservation of Plasterworks from the Islamic Tradition     

Francisco José Collado-Montero  Ana Isabel Calero-Castillo  Manuel Melgosa  Víctor Jesús Medina 《文物保护研究》2013,58(2):90-100

ABSTRACT

The main aim of our current investigation is the colorimetric evaluation of protective treatments (consolidants) applied to traditional Islamic plasterworks, under natural ageing conditions. From analyses of the original pictorial plaster remains in the Courtyard of the Maidens of the Real Alcázar in Seville, Spain (a World Heritage Site) we prepared test specimens, using materials and techniques similar to the original ones. We analysed 56 test specimens painted with four pigments (yellow, green, blue, and red), using two different binders (animal glue and gum arabic), onto which five representative consolidants were applied: barium hydroxide, acrylic copolymer, polyvinyl butyral, ethyl silicate, and bacterial carbonatogenesis. The test specimens were subjected to natural ageing for one year (indoors and outdoors), enabling a colorimetric assessment to be made of the changes of the polychrome surfaces. The colorimetric heterogeneity of the 56 specimens after ageing registered an average value of 2.7 CIELAB units, assessed using the mean colour difference with respect to the mean. In the aged specimens, the addition of consolidants resulted in average colour differences (mainly lightness differences) of 10.7 and 6.7 CIELAB units, considering as a reference the specimens without consolidants aged indoors and outdoors, respectively. These colour differences were very similar for both binders but not for the four pigments, higher values being found for the blue and red pigments. Considering as reference the samples without consolidants aged outdoors, we found no statistically significant colour differences, either among the five consolidants (p?=?.094) nor the two binders (p?=?.674) used. In addition to the magnitude of colour differences, the choice of the most appropriate consolidants must also consider aspects related to performance and effectiveness. Overall, for the type of paints tested, the polyvinyl butyral consolidant appeared to perform the best, followed by the ethyl silicate.  相似文献   

Effects of mat characteristics on plantar pressure patterns and perceived mat properties during landing in gymnastics     

Pérez-Soriano P  Llana-Belloch S  Morey-Klapsing G  Perez-Turpin JA  Cortell-Tormo JM  van den Tillaar R 《Sports biomechanics / International Society of Biomechanics in Sports》2010,9(4):245-257

Shock absorption and stability during landings is provided by both, gymnast ability and mat properties. The aims of this study were to determine the influence of different mat constructions on their energy absorption and stability capabilities, and to analyse how these properties affect gymnast's plantar pressures as well as subjective mat perception during landing. Six mats were tested using a standard mechanical drop test. In addition, plantar pressures and subjective perception during landing were obtained from 15 expert gymnasts. The different mats influenced plantar pressures and gymnasts' subjective perception during landing of gymnasts. Significant correlations between plantar pressures at the medial metatarsal and lateral metatarsal zones of the gymnasts' feet with the different shock absorption characteristics of the mats were found. However, subjective perception tests were not able to discriminate mat functionality between the six mats as no significant correlations between the mechanical mat properties with the subjective perception of these properties were found. This study demonstrated that plantar pressures are a useful tool for discriminating different landing mats. Using similar approaches, ideally including kinematics as well, could help us in our understanding about the influences of different mats upon gymnast-mat interaction.  相似文献