Tubespins as a suitable scale-down model of 2L high cell density bioreactors for CHO cell culture

High cell-density culture of Chinese Hamster Ovary (CHO) cells significantly increases cell growth, viability and volumetric productivity of recombinant therapeutic proteins. These improvements can reduce size or number of manufacturing cell culture vessels, decrease plant footprint and ultimately, the cost of goods. Process development is typically performed in instrumented lab-scale bioreactors, which, while effective, require time and labor for set-up and operation. Is it attractive to develop alternate systems that provide representative results but without the effort of bioreactor operation. To this effect, we evaluated 50 mL Tubespins as a model to mimic high cell density cultures. We tested 13 different CHO cell lines expressing recombinant proteins for 12 - 15 days concurrently in both 2L bioreactors and satellite 50 mL Tubespins. In general, Tubespins exhibited comparable cell viability and specific productivity to 2L bioreactors and with generally comparable high peak cell densities. Finally, product quality attributes such as galactosylation, afucosylation, and protein aggregation in Tubespins were similar to those in 2L bioreactors. Some differences were seen in protein charge heterogeneity and these could be attributed to the residence time differences between the systems. In summary, Tubespins can be used as an effective tool for CHO high cell density process development with 150-fold lower medium usage, no time-consuming or labor-intensive bioreactor preparation, and providing valuable and representative results of cell line growth, metabolism, productivity and product quality

Effects of a radially varying electrical conductivity on 3D numerical dynamos

The transition from liquid metal to silicate rock in the cores of the terrestrial planets is likely to be accompanied by a gradient in the composition of the outer core liquid. The electrical conductivity of a volatile enriched liquid alloy can be substantially lower than a light-element-depleted fluid found close to the inner core boundary. In this paper, we investigate the effect of radially variable electrical conductivity on planetary dynamo action using an electrical conductivity that decreases exponentially as a function of radius. We find that numerical solutions with continuous, radially outward decreasing electrical conductivity profiles result in strongly modified flow and magnetic field dynamics, compared to solutions with homogeneous electrical conductivity. The force balances at the top of the simulated fluid determine the overall character of the flow. The relationship between Coriolis and Lorentz forces near the outer boundary controls the flow and magnetic field intensity and morphology of the system. Our results imply that a low conductivity layer near the top of Mercury's liquid outer core is consistent with its weak magnetic field.Comment: 30 pages, 11 figures, 2 tables. To be published in Physics of Earth and Planetary Interiors (PEPI)

GENDER VIOLENCE IN THE PRESS: A CRITICAL ANALYSIS OF THREE ARGENTINEAN NEWSPAPERS

Gender violence appears to have entered the Argentinean media spotlight, as demonstrated by the increasing amount of press coverage dealing with different types of male aggression on women. In my work, I study the representation that three national newspapers in Argentina, i.e. Página 12, La Nación and Crítica de la Argentina, make on cases of physical violence against women by men. I draw on critical discourse analysis and critical gender studies to move from the linguistic form into the ideological content of the texts. In particular, I follow an analytical heuristic that focuses on the 'naming', 'voicing' and 'agency' devices employed by the journalists in order to arrive at the gender ideologies that support the language surface. Five out of six ideologies correspond to a patriarchal discourse which (1) deems poor women more prone to the violence, (2) holds women silent and passive in the face of male abuse, (3) blames women for the violence they suffer from, (4) views women as disposable objects, and (5) punishes women for breaching the public/private divide. A sixth ideology was also revealed in some of the articles. Ideology (6) challenges the patriarchy-based ideologies by establishing that women are not inferior to men, and consequently, women's emancipation from violent men must be fostered. The driving force behind my study of press representations of gender violence in Argentina springs from the conception of language as social action. Overall, this thesis stands as a work which demonstrates the value of media literacy, a movement that falls within the realm of "educommunication", which promotes a critical stance before the media messages around us

Promoting Solar electricity exports from Southern to Central and Northern European countries: Extremadura case study

In the light of the EU Energy and Climate framework, exporting solar electricity from South to Central and Northern Europe can contribute to various EU strategic objectives. However, as of today, some challenges prevent its materialization. To address some of these obstacles and as part of the Smart Specialization Platform on Energy activities, this policy report provides answers to two key questions: (i) what is the value proposition of solar electricity exports in Europe? (ii) How can these projects be feasible?JRC.C.6-Economics of Climate Change, Energy and Transpor

Low and high frequency approximations to eigenvibrations of string with double contrasts

We study eigenvibrations for inhomogeneous string consisting of two parts with strongly contrasting stiffness and mass density. In this work we treat a critical case for the high frequency approximations, namely the case when the order of mass density inhomogeneity is the same as the order of stiffness inhomogeneity, with heavier part being softer. The limit problem for high frequency approximations depends nonlinearly on the spectral parameter. The quantization of the spectral semiaxies is applied in order to get a close approximations of eigenvalues as well as eigenfunctions for the prime problem under perturbation.Comment: 13 pages, 6 plots; submitted for publication; typos added

Offshore drilling blowout risk model : an integration of basic causes, safety barriers, risk influencing factors and operational performance indicators

We would like to thank Witt O’Brien’s Brasil and Pemex Exploration and Production for partially sponsoring this work, and most of all: Adriano Ranieri, Greg Fenton, Flavio Andrade, Dr. Faustino Fuentes Nucamendi and Eduardo Zavala Nacer. Thanks also to Mr. Thiago Molina for providing his expertise on latest generation Deepwater MODU's, which enabled to add current and practical aspects to the academic research on kick detection and well control issues.Peer reviewedPostprin

AVIFAUNA DE LOS BOSQUES RIBEREÑOS DE LAS SELVAS PEDEMONTANAS DEL NOROESTE ARGENTINO

RESUMEN Los bosques de ribera usualmente hacen referencia a un cuerpo de agua y su bosque asociado, y representan una zona de transición entre el ambiente acuático y el entorno. Estos bosques, constituyen hábitats particulares que proveen sitios de alimentación y reproducción, y rutas de paso para numerosas especies. En general, albergan una rica y abundante fauna en comparación con los ambientes no ribereños circundantes. Las aves constituyen un grupo conspicuo en los bosques de ribera, tanto en regiones templadas como tropicales y frecuentemente los ensambles son diferentes y de mayor riqueza específica que los de áreas vecinas. En este estudio examinamos en detalle la diversidad de los ensambles de aves en seis bosques de ribera de la selva pedemontana del noroeste de la Argentina (Yungas Australes) y comparamos la riqueza y abundancia de las aves entre la temporada seca y húmeda. Encontramos un total de 207 especies de aves. Las especies migratorias latitudinales y altitudinales representaron el 15% y 9% de las especies de aves, respectivamente. Los ensambles de aves entre las temporadas seca y húmeda fueron significativamente diferentes (ANOSIM: R = 0,32, p = 0,02) si bien estas diferencias fueron moderadas. El 30% de las 56 especies que más contribuyeron a esta diferenciación fueron aves migratorias. El gremio trófico más representativo fue el de las aves insectívoras, seguido de las granívoras. Los bosques de ribera estuvieron dominados por especies de aves que típicamente habitan bosques maduros de las Yungas Australes. Registramos una especie clasificada globalmente como “Casi Amenazada” y cuatro especies consideradas Amenazadas a escala nacional. Este trabajo resalta la importancia de los bosques de ribera en su rol como refugio tanto para las especies de aves migratorias como residentes, contribuyendo a la diversidad regional. ABSTRACT ∙ Bird assemblages of riparian forests of premontane forests in northwestern ArgentinaRiparian forests usually refer to a water‐body and its associated forest, and represent a transitional zone between the aquatic environment and the surrounding area. These forests are singular habitats that provide feeding and breeding sites as well as migration routes for many species. Usually, the fauna found in riparian forests is more diverse and abundant than in surrounding, non‐riparian habitats. Birds are a conspicuous group in riparian forests, both in temperate and tropical regions, and they often form very distinctive assemblages compared to neighboring areas. In this study, we examined in detail the diversity of bird assemblages at six riparian forests within the piedmont of a subtropical montane forest from NW Argentina (Southern Yungas), assessing their richness and abundance in the wet and dry seasons. We found a total of 207 bird species. Latitudinal and altitudinal migrants represented 15% and 9% of species, respectively. Birds assemblages in the wet and dry seasons were significantly different (ANOSIM: R = 0.32, p = 0.02) although differences were relatively small. Thirty percent of the 56 species that contribute most to this difference were migratory birds. Insectivorous birds, followed by granivorous birds, were the best represented trophic guilds. Riparian forests were dominated by bird species that typically occur in undisturbed, mature forests of the Southern Yungas. We recorded one species classified as “Near Threatened” at a global scale, and four species considered “Threatened” at a national scale. This study points out the importance of riparian forests as refuges for migratory as well as resident bird species, which can be crucial for the maintenance of the regional bird diversity

Evaluation of cell culture with a simulated continuous manufacturing (sCM) process in 50mL tubespins for clone selection

Continuous Manufacturing (CM) is a process where perfusion cell culture for \u3e30 days is performed with a pre-defined constant biomass set point achieved by bleeding extra cells from the bioreactor (BR). Requirements for cell lines cultured in CM include: (1) good growth to achieve biomass set-point and maintain viability \u3e90%; (2) constant cell-specific productivity as function of culture time (and consequently, volumetric productivity); and (3) constant product quality as function of culture time. In comparison to traditional batch or fed-batch cultures, early screening of numerous clones for a CM process may need to include further evaluation of these three additional attributes to better choose the top performing clones in a CM-like culture. With this purpose, we evaluated a small-scale simulated CM process (sCM) in 50mL Tubespins to screen up to 20 different clones simultaneously. This sCM small-scale model mimics a BR CM process with a simulated perfusion via daily medium exchange. Additionally, sCM can match the cell-specific perfusion rate (CSPR) in the CM BR and includes a discrete daily manual bleed to maintain a target cell density. We performed two sets of experiments to determine sCM performance including (1) evaluation of 16 cell lines expressing a model molecule and cultured in both sCM and small-scale fed-batch process, and (2) evaluation of 5 clones in both sCM and 2L CM BR. Our results indicate clone ranking accordingly to product quality is comparable between small-scale fed-batch and sCM, but ranking accordingly to viability and growth could differ between the two formats. Comparing to BR CM results, sCM predicts well daily volumetric productivity and overall growth performance, but final viability is lower in sCM for some clones. Overall product quality trends as function of culture time were similar between BR CM and sCM. In summary, we established a small-scale Tubespin model for CM that could be used as an additional tool during clone screening

Novel periodic alternating tangential filtration harvest approach provides incresed volumetric productivity

Perfusion cell culture processes provide opportunities to increase product yield through improved cell growth, increased productivity and extended process duration. Most commonly, perfusion cell culture also leads to a continuous harvest operation and collection of harvested cell culture fluid to be processed downstream. As an alternative to continuous harvest, we evaluated instead a periodic harvest approach applied to a non-steady state perfusion cell culture process using alternative tangential flow (ATF). In this ATF perfusion process, product is first accumulated in the bioreactor using ultrafiltration for 15 days with the product then being harvested by microfiltration at end of the process. To further extend the culture time beyond 15 days and maximize productivity, we investigated a sequence of five periodic harvests from a single upstream bioreactor run. The periodic harvests were achieved using an ATF configuration in which ultrafiltration and microfiltration hollow fiber filters were stacked in series (Figure 1). The ultrafiltration hollow fiber retains the product while the microfiltration filter allows product to be collected in the permeate. Permeate was only drawn from the microfiltration filter during the periodic harvest cycles while the permeate was drawn from the ultrafiltration filter during the none harvest cycle periods. This allowed for the accumulation of product in the bioreactor between the periodic harvests. Five harvest cycles were conducted over a 24-day perfusion process. Each harvest cycle was collected for a day with the first harvest cycle starting on day 11. Please click Additional Files below to see the full abstract

Integrated AlGaAs source of highly indistinguishable and energy-time entangled photons

The generation of nonclassical states of light in miniature chips is a crucial step towards practical implementations of future quantum technologies. Semiconductor materials are ideal to achieve extremely compact and massively parallel systems and several platforms are currently under development. In this context, spontaneous parametric down conversion in AlGaAs devices combines the advantages of room temperature operation, possibility of electrical injection and emission in the telecom band. Here we report on a chip-based AlGaAs source, producing indistinguishable and energy-time entangled photons with a brightness of $7.2\times10^6$ pairs/s and a signal-to-noise ratio of $141\pm12$. Indistinguishability between the photons is demonstrated via a Hong-Ou-Mandel experiment with a visibility of $89\pm3\%$, while energy-time entanglement is tested via a Franson interferometer leading to a value for the Bell parameter $S=2.70\pm0.10$