Bridging the Disconnect

New York City is facing a youth unemployment crisis, but the city's youth workforce development programs reach only a fraction of those in need of help and are too often misaligned to the developmental needs of young New Yorkers

Moment-based analysis of biochemical networks in a heterogeneous population of communicating cells

Cells can utilize chemical communication to exchange information and coordinate their behavior in the presence of noise. Communication can reduce noise to shape a collective response, or amplify noise to generate distinct phenotypic subpopulations. Here we discuss a moment-based approach to study how cell-cell communication affects noise in biochemical networks that arises from both intrinsic and extrinsic sources. We derive a system of approximate differential equations that captures lower-order moments of a population of cells, which communicate by secreting and sensing a diffusing molecule. Since the number of obtained equations grows combinatorially with number of considered cells, we employ a previously proposed model reduction technique, which exploits symmetries in the underlying moment dynamics. Importantly, the number of equations obtained in this way is independent of the number of considered cells such that the method scales to arbitrary population sizes. Based on this approach, we study how cell-cell communication affects population variability in several biochemical networks. Moreover, we analyze the accuracy and computational efficiency of the moment-based approximation by comparing it with moments obtained from stochastic simulations.Comment: 6 pages, 5 Figure

The evolution of ideas in biomimicry

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2011.Cataloged from PDF version of thesis.Includes bibliographical references (p. 28-30).The aim of this paper is to perform a review of Biomimicry as a science today in environmental, engineering, and manufacturing fields, as well as to educate readers on the history of Biomimicry as a whole and how it is studied. As more evidence surfaces about the effect of our presence on the Earth, the scientific community is faced with the challenge of solving these problems. After introducing these concepts, an in-depth review of two of the most studied topics in biomimicry is conducted: how the lotus remains clean in a dirty swamp and how the gecko can stick to any surface. These two topics are taken from the classical beliefs on how they work and leads them through into today's world, focusing on how the mechanisms behind them were discovered. Both sections end with a review of current applications of the technologies that have been developed by studying these living organisms. Everything is wrapped up with a discussion of why we must continue to study biomimicry and apply its principles to our engineering and production practices.by Phillip David Gonzales.S.B

Building synthetic multicellular systems from the bottom-up

Biological cell populations, such as in tissues or microbial communities, are constantly subject to different sources of noise and variability. Despite this, multicellular systems are still able to function properly because cells coordinate with each other by communication. Using biological model systems to study this multiscalar process can be challenging because of their innate complexity. In this thesis, we address this challenge by building a synthetic multicellular system using bottom-up in vitro assembly approaches. Using this platform, we aim to study the effect of cell-to-cell communication to population variability in a minimal and simplified context. To achieve this, we require a synthetic cell population with (i) quantifiable gene expression dynamics, (ii) customizable population variability, and (iii) intercellular communication. Having these characteristics will allow us to test different initial configurations of population variability and monitor population gene expression dynamics with and without cell-to-cell communication. To generate these synthetic cell populations, reconstituted cell-free expression systems (CFES) are encapsulated into monodisperse-sized liposomes using double-emulsion microfluidics. Both transcription and translation levels are simultaneously monitored and quantified to develop models of cell-free gene expression dynamics and differentiate between bulk and encapsulated formats. Population variability was then incorporated by combining different batches of cells to create distinct subpopulations or by using a two-inlet double-emulsion microfluidic device to generate single populations with a large dispersion of encapsulated DNA template. Lastly, genetic circuits based on the quorum sensing system of Vibrio fischeri are used to implement diffusion-mediated intercellular signalling. Quorum sensing gene circuits in Escherichia coli extract-based CFES were tested in bulk and phase transfer-generated synthetic cells. Together with these experimental systems, corresponding models of synthetic cell populations that can account for population variability and secrete-and-sensing communication are developed using mixed-effects models and moment dynamics. Overall, this work leverages CFES and microfluidic technologies to reproducibly generate a simplified in vitro model of multicellular systems that can be easily monitored spatiotemporally to study multi-scalar processes.:Preface Chapter 1 Bottom-up multicellular systems Chapter 2 Building blocks: cell-free expression and liposomes Chapter 3 Gene expression dynamics in synthetic cell populations Chapter 4 Variability and communication in synthetic cell populations Chapter 5 Modeling variability & communication in synthetic cell populations Summary and outlook Appendices BibliographyBiologische Zellpopulationen, z.B. in Geweben oder mikrobiellen Gemeinschaften, sind ständig verschiedenen Quellen von Rauschen und Variabilität ausgesetzt. Trotzdem sind multizelluläre Systeme in der Lage, ordnungsgemäß zu funktionieren, weil sich die Zellen durch Kommunikation miteinander abstimmen. Die Verwendung biologischer Modellsysteme zur Untersuchung dieses multiskalaren Prozesses kann aufgrund ihrer angeborenen Komplexität eine Herausforderung darstellen. In dieser Arbeit gehen wir diese Herausforderung an, indem wir ein synthetisches multizelluläres System mit Hilfe von Bottom-up-in vitro-Assembly-Ansätzen aufbauen. Mit Hilfe dieser Plattform wollen wir die Auswirkungen der Kommunikation von Zelle zu Zelle auf die Populationsvariabilität in einem minimalen und vereinfachten Kontext untersuchen. Um dies zu erreichen, benötigen wir eine synthetische Zellpopulation mit (i) quantifizierbarer Genexpressionsdynamik, (ii) anpassbarer Populationsvariabilität und (iii) interzellulärer Kommunikation. Mit diesen Eigenschaften können wir verschiedene Ausgangskonfigurationen der Populationsvariabilität testen und die Genexpressionsdynamik der Population mit und ohne Zell-zu-Zell-Kommunikation beobachten. Um diese synthetischen Zellpopulationen zu erzeugen, werden rekonstituierte zellfreie Expressionssysteme (CFES) mit Hilfe der Doppelemulsions-Mikrofluidik in monodisperse Liposomen eingekapselt. Sowohl die Transkriptions- als auch die Translationsraten werden gleichzeitig überwacht und quantifiziert, um Modelle für die Dynamik der zellfreien Genexpression zu entwickeln und zwischen Bulk- und verkapselten Formaten zu unterscheiden. Die Variabilität der Populationen wurde dann durch die Kombination verschiedener Zellchargen zur Bildung unterschiedlicher Subpopulationen oder durch die Verwendung einer mikrofluidischen Doppelemulsionsvorrichtung mit zwei Einlässen zur Erzeugung einzelner Populationen mit einer großen Streuung der eingekapselten DNA-Vorlage einbezogen. Schließlich werden genetische Schaltkreise auf der Grundlage des Quorum-Sensing-Systems von Vibrio fischeri verwendet, um diffusionsvermittelte interzelluläre Signalübertragung zu implementieren. Quorum-Sensing-Genkreisläufe in CFES auf der Basis von Escherichia coli-Extrakten wurden in synthetischen Zellen getestet, die durch Bulk- und Phasentransfer erzeugt wurden. Zusammen mit diesen experimentellen Systemen wurden entsprechende Modelle synthetischer Zellpopulationen entwickelt, die die Populationsvariabilität und die Sekretions- und Sensing-Kommunikation mit Hilfe von Mixed-Effects-Modellen und Momentendynamik berücksichtigen können. Insgesamt nutzt diese Arbeit CFES- und Mikrofluidik-Technologien, um reproduzierbar ein vereinfachtes in vitro-Modell multizellulärer Systeme zu erzeugen, das leicht raum-zeitlich überwacht werden kann, um multiskalare Prozesse zu untersuchen.:Preface Chapter 1 Bottom-up multicellular systems Chapter 2 Building blocks: cell-free expression and liposomes Chapter 3 Gene expression dynamics in synthetic cell populations Chapter 4 Variability and communication in synthetic cell populations Chapter 5 Modeling variability & communication in synthetic cell populations Summary and outlook Appendices Bibliograph

El recurso presupuestal y la eficiencia del programa de complementación alimentaria en la municipalidad magdalena del mar – 2015

La presente investigación tuvo como objetivo determinar la relación entre el recurso presupuestal y la eficiencia del programa de complementación alimentaria en la Municipalidad de Magdalena del Mar, 2015. El presente estudio fue del tipo básico, con un diseño no experimental de corte transversal y de nivel descriptivo correlacional; la población estuvo conformada por 50 supervisores (titulares y suplentes) del Programa de Complementación Alimentaria de la Municipalidad de Magdalena del Mar. La técnica fue encuesta y se emplearon cuestionarios como instrumentos de recolección de datos, que fueron debidamente validados y determinados su confiabilidad mediante el Alfa de Cronbach Se llegó a la siguiente conclusión: Existen evidencias suficientes para afirmar que el recurso presupuestal tiene correlación inversa baja (Rho = -0.312) y significativa (p=0.028 menor que 0.05) con la eficiencia del Programa de Complementación Alimentaria en la Municipalidad de Magdalena del Mar - 2015

Rodent Aβ Modulates the Solubility and Distribution of Amyloid Deposits in Transgenic Mice

The amino acid sequence of amyloid precursor protein (APP) is highly conserved, and age-related Abeta aggregates have been described in a variety of vertebrate animals, with the notable exception of mice and rats. Three amino acid substitutions distinguish mouse and human Abeta that might contribute to their differing properties in vivo. To examine the amyloidogenic potential of mouse Abeta, we studied several lines of transgenic mice overexpressing wild-type mouse amyloid precursor protein (moAPP) either alone or in conjunction with mutant PS1 (PS1dE9). Neither overexpression of moAPP alone nor co-expression with PS1dE9 caused mice to develop Alzheimer-type amyloid pathology by 24 months of age. We further tested whether mouse Abeta could accelerate the deposition of human Abeta by crossing the moAPP transgenic mice to a bigenic line expressing human APPswe with PS1dE9. The triple transgenic animals (moAPP x APPswe/PS1dE9) produced 20% more Abeta but formed amyloid deposits no faster and to no greater extent than APPswe/PS1dE9 siblings. Instead, the additional mouse Abeta increased the detergent solubility of accumulated amyloid and exacerbated amyloid deposition in the vasculature. These findings suggest that, although mouse Abeta does not influence the rate of amyloid formation, the incorporation of Abeta peptides with differing sequences alters the solubility and localization of the resulting aggregates

MODELO DE ANALISIS PARA INCADORES DE LESIONES OSEAS POR ANEMIA EN EL ANTIGUO PERU

Es los trabajos de investigación relacionado a las enfermedades prehispánicas permitió determinar una serie de lesiones óseas en el antiguo Perú, por cuanto se vuelve necesario establecer las condiciones para que los estudios relacionados a la anemia en el pasado puedan ser evaluados bajo un modelo para los indicadores de lesiones. Se determinó tres elementos para conseguir un modelo de análisis de para indicadores de lesiones por anemia, a través de una teorización de los resultados en el tiempo, imágenes relacionadas a lesiones en la cabeza como son Criba Orbitalia (CO) y Hiperostosis porotica (HP) y finalmente la extracción tabla de lesiones en los huesos. Se pudo corroborar que existen investigaciones que reflejan la presencia de lesiones en el cráneo humano provocado por la anemia, pero a la vez no determinan un modelo, así como indicadores óseos por la enfermedad. Por cuanto podemos afirmar que para tener la certeza que nos encontramos ante lesiones de hueso provocado por anemia debemos focalizar esfuerzos analizando en las áreas del frontal mediante la Corteza Prefrontal (CPF) en la superficie orbital, así como en el parietal a través de los forámenes parietales (FP) del cráneo humano