Medium dependence of multiplicity distributions in MLLA

We study the modification of the multiplicity distributions in MLLA due to the presence of a QCD medium. The medium is introduced though a multiplicative constant ($f_{med}$) in the soft infrared parts of the kernels of QCD evolution equations. Using the asymptotic ansatz for quark and gluons mean multiplicities $=e^{\gamma y}$ and $=r^{-1}e^{\gamma y}$ respectively, we study two cases: fixed $\gamma$ as previously considered in the literature, and fixed $\alpha_s$. We find opposite behaviors of the dispersion of the multiplicity distributions with increasing $f_{med}$ in both cases. For fixed $\gamma$ the dispersion decreases, while for fixed $\alpha_s$ it increases.Comment: LaTeX, 9 pages, 4 eps figures; proceedings of the 3rd International Conference on Hard and Electromagnetic Probes in High-Energy Nuclear Collisions - Hard Probes 2008 (Illa de A Toxa, Spain, June 8th-14th 2008

Obtención de un polímero de tipo Elastina modificado con secuencias Bioactivas y Biodegradables, para su aplicación en ingeniería

La matriz extracelular es uno de los principales elementos reguladores de la actividad celular. Los diferentes módulos de las macromoléculas que la componen son capaces de desencadenar señales que activan diferentes rutas intracelulares que organizan las funciones vitales de las células. La ingeniería de tejidos se dedica a desarrollar sistemas capaces de imitar, temporalmente, el comportamiento de la matriz extracelular con objeto de promover la regeneración o el reemplazo de tejidos y órganos dañados, actuando como un soporte atractivo para las células que deben adherirse y crecer sobre ella, hasta reemplazarla por tejido sano. En este trabajo se describe el proceso de diseño y producción de un polímero de tipo elastina que se ha funcionalizado con secuencias bioactivas que añaden actividades específicas al andamio o soporte celular que constituye la elastina. Así,algunos dominios elastoméricos se modificaron con el aminoácido lisina para poder entrecruzar las moléculas de polímero y conseguir matrices. También se incluyó la secuencia REDV, presente el dominio CS5 de la fibronectina humana, como motivo de adhesión celular. Por último, el polímero se funcionalizó con secuencias diana de enzimas proteolíticas para mejorar su bioprocesabilidad.Extracellular matrix (ECM) is a major component for the regulation of cell activity. The different modules of the proteins which constitute the extracellular matrix macromolecules represent for the cells which enter in contact with them, new signals capable of activating several intracellular signaling pathways, resulting in the modulation of numerous cell functions. Tissue engineering tries to develop new materials based on these components as scaffolds for cells to promote their adhesion and growth. In this work, genetic engineering techniques were used to design and biosynthesize an extracellular matrix analogue based in the elastin component. The structural base of our scaffold is an elastin –derived sequence which confers an adequate mechanical behavior. In addition, several domains were included, for adding new bioactivities to this elastin-like polymer (ELP). Some of these elastic domains were modified to contain lysine for cross linking purposes. The polymer also contained periodically spaced fibronectin CS5 domain enclosing the well known cell attachment sequence REDV. Finally, the polymer had target sequences for proteolitic action.Peer ReviewedAward-winnin

Reliability of low-cost near-infrared spectroscopy in the determination of muscular oxygen saturation and hemoglobin concentration during rest, isometric and dynamic strength activity

Indexación ScopusBackground: The objective of this study was to establish the reliability of the Humon Hex near-infrared reflectance spectroscopy (NIRS) in determining muscle oxygen saturation (SmO2) and hemoglobin concentration (Hgb) at rest and during isometric and dynamic strength exercises using a functional electromechanical dynamometer (FEMD). Methods: The SmO2 and Hgb values of sixteen healthy adults (mean ± standard deviation (SD): Age = 36.1 ± 6.4 years) were recorded at rest and during isometry (8 s), dynamic strength I (initial load of 40% of the average isometric load, with 2 kg increments until muscle failure) and dynamic strength II (same as I, but with an initial load of 40% of the maximum isometric load) activity. To evaluate the reliability in the determination of SmO2 and Hgb of this device, intraclass correlation coefficient (ICC), standard error of measurement (SEM) and coefficient of variation (CV) were obtained. Results: The main results obtained are SmO2 at rest (CV = 5.76%, SEM = 3.81, ICC = 0.90), isometric strength (CV = 3.03%, SEM = 2.08, ICC = 0.92), dynamic strength I (CV = 10.6, SEM = 7.17, ICC = 0.22) and dynamic strength II (CV = 9.69, SEM = 6.75, ICC = 0.32); Hgb at rest (CV = 1.97%, SEM = 0.24, ICC = 0.65), isometric strength (CV = 0.98%, SEM = 0.12, ICC = 0.96), dynamic strength I (CV = 3.25, SEM = 0.40, ICC = 0.54) and dynamic strength II (CV = 2.74, SEM = 0.34, ICC = 0.65). Conclusions: The study shows that Humon Hex is a reliable device to obtain SmO2 and Hgb data in healthy adult subjects at rest and during isometric strength, providing precision for measurements made with this device. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.https://www.mdpi.com/1660-4601/17/23/882

Establishment and cryptic transmission of Zika virus in Brazil and the Americas

Transmission of Zika virus (ZIKV) in the Americas was first confirmed in May 2015 in northeast Brazil1. Brazil has had the highest number of reported ZIKV cases worldwide (more than 200,000 by 24 December 20162) and the most cases associated with microcephaly and other birth defects (2,366 confirmed by 31 December 20162). Since the initial detection of ZIKV in Brazil, more than 45 countries in the Americas have reported local ZIKV transmission, with 24 of these reporting severe ZIKV-associated disease3. However, the origin and epidemic history of ZIKV in Brazil and the Americas remain poorly understood, despite the value of this information for interpreting observed trends in reported microcephaly. Here we address this issue by generating 54 complete or partial ZIKV genomes, mostly from Brazil, and reporting data generated by a mobile genomics laboratory that travelled across northeast Brazil in 2016. One sequence represents the earliest confirmed ZIKV infection in Brazil. Analyses of viral genomes with ecological and epidemiological data yield an estimate that ZIKV was present in northeast Brazil by February 2014 and is likely to have disseminated from there, nationally and internationally, before the first detection of ZIKV in the Americas. Estimated dates for the international spread of ZIKV from Brazil indicate the duration of pre-detection cryptic transmission in recipient regions. The role of northeast Brazil in the establishment of ZIKV in the Americas is further supported by geographic analysis of ZIKV transmission potential and by estimates of the basic reproduction number of the virus

The Effectiveness of a Novel Cartridge-Based Bioreactor Design in Supporting Liver Cells

There are a number of applications—ranging from temporary strategies for organ failure to pharmaceutical testing—that rely on effective bioreactor designs. The significance of these devices is that they provide an environment for maintaining cells in a way that allows them to perform key cellular and tissue functions. In the current study, a novel cartridge-based bioreactor was developed and evaluated. Its unique features include its capacity for cell support and the adaptable design of its cellular space. Specifically, it is able to accommodate functional and reasonably sized tissue (>2.0 × 108 cells), and can be easily modified to support a range of anchorage-dependent cells. To evaluate its efficacy, it was applied to liver support in the current study. This involved evaluating the performance of rat primary hepatocytes within the unique cartridges in culture—sans bioreactor—and after being loaded within the novel bioreactor. Compared to collagen sandwich culture functional controls, hepatocytes within the unique cartridge design demonstrated significantly higher albumin production and urea secretion rates when cultured under dynamic flow conditions—reaching peak values of 170 ± 22 μg/106 cells/day and 195 ± 18 μg/106 cells/day, respectively. The bioreactor's effectiveness in supporting live and functioning primary hepatocytes is also presented. Cell viability at the end of 15 days of culture in the new bioreactor was 84 ± 18%, suggesting that the new design is effective in maintaining primary hepatocytes for at least 2 weeks in culture. Liver-specific functions of urea secretion, albumin synthesis, and cytochrome P450 activity were also assessed. The results indicate that hepatocytes are able to achieve good functional performance when cultured within the novel bioreactor. This is especially true in the case of cytochrome P450 activity, where by day 15 of culture, hepatocytes within the bioreactor reached values that were 56.6% higher than achieved by the collagen sandwich functional control cultures. The success of the novel cartridge-based bioreactor in supporting hepatocytes with good viability and functional performance suggests that it is an effective design for supporting anchorage-dependent cells

The Design of In Vitro Liver Sinusoid Mimics Using Chitosan–Hyaluronic Acid Polyelectrolyte Multilayers

Interactions between hepatocytes and liver sinusoidal endothelial cells (LSECs) are essential for the development and maintenance of hepatic phenotypic functions. We report the assembly of three-dimensional liver sinusoidal mimics comprised of primary rat hepatocytes, LSECs, and an intermediate chitosan–hyaluronic acid polyelectrolyte multilayer (PEM). The height of the PEMs ranged from 30 to 55 nm and exhibited a shear modulus of ∼100 kPa. Hepatocyte–PEM cellular constructs exhibited stable urea and albumin production over a 7-day period, and these values were either higher or similar to cells cultured in a collagen sandwich. This is of significance because the thickness of a collagen gel is ∼1000-fold higher than the height of the chitosan–hyaluronic acid PEM. In the hepatocyte–PEM–LSEC liver-mimetic cellular constructs, LSEC phenotype was maintained, and these cultures exhibited stable urea and albumin production. CYP1A1/2 activity measured over a 7-day period was significantly higher in the hepatocyte–PEM–LSEC constructs than in collagen sandwich cultures. A 16-fold increase in CYP1A1/2 activity was observed for hepatocyte–PEM–10,000 LSEC samples, thereby suggesting that interactions between hepatocytes and LSECs are critical in enhancing the detoxification capability in hepatic cultures in vitro