6 research outputs found
Optimization of the single use bioreactor for growth and bead-to-bead transfer of Vero cells cultured on microcarriers
Scale up and vaccine production processes of adherent cells, such as Vero cells face many challenges. The fundamental steps of equipment selection and chosen operating parameters have a significant impact upon the detachment and reattachment of cells through the scale up process. Microcarriers greatly increase the surface area for adherent cells and offer flexibility for expansion to bioreactors, but scale-up methods require optimization of the mixing within the vessel and also optimization of how the cells are transferred from bead to bead at each step in the seed train. In this study we take a process previously shown to a work in spinner flasks (\u3c1L)1 and demonstrate how the 50L Thermo Scientificâ„¢ HyPerformaâ„¢ Single-Use Bioreactors (S.U.B.) can be optimized for growing and scaling adherent cells on microcarriers, methods for bead-to-bead transfer of the cells at each scaling step, and final cell isolation using the Harvestainer single use bead capture bag.
References Hachmann A, Campbell A, Gorfien S. Scale-up Optimization of Vero Cells Cultured on Microcarriers in Serum-Free Medium for Vaccine Production. Poster presented at: Vaccine Technology VI; 2016 June 12-17; Albufeira, Portugal
Production of Lightning NO(x) and its Vertical Distribution Calculated from 3-D Cloud-scale Chemical Transport Model Simulations
A 3-D cloud scale chemical transport model that includes a parameterized source of lightning NO(x), based on observed flash rates has been used to simulate six midlatitude and subtropical thunderstorms observed during four field projects. Production per intracloud (P(sub IC) and cloud-to-ground (P(sub CG)) flash is estimated by assuming various values of P(sub IC) and P(sub CG) for each storm and determining which production scenario yields NO(x) mixing ratios that compare most favorably with in-cloud aircraft observations. We obtain a mean P(sub CG) value of 500 moles NO (7 kg N) per flash. The results of this analysis also suggest that on average, P(sub IC) may be nearly equal to P(sub CG), which is contrary to the common assumption that intracloud flashes are significantly less productive of NO than are cloud-to-ground flashes. This study also presents vertical profiles of the mass of lightning NO(x), after convection based on 3-D cloud-scale model simulations. The results suggest that following convection, a large percentage of lightning NO(x), remains in the middle and upper troposphere where it originated, while only a small percentage is found near the surface. The results of this work differ from profiles calculated from 2-D cloud-scale model simulations with a simpler lightning parameterization that were peaked near the surface and in the upper troposphere (referred to as a "C-shaped" profile). The new model results (a backward C-shaped profile) suggest that chemical transport models that assume a C-shaped vertical profile of lightning NO(x) mass may place too much mass neat the surface and too little in the middle troposphere
Multi-fractal analysis of nocturnal boundary layer time series from the Boulder Atmospheric Observatory.
Time series from a nocturnal boundary layer are analyzed using fractal
techniques. The behavior of the self-affine fractal dimension, D A , is
found to drop during a gravity wave train and rise with turbulence. D A is
proposed as a time series conditional sampling criterion for
distinguishing waves from turbulence. Only weak correlations are found
between DA and bulk turbulence measures such as Brunt-Vaisala frequency,
Richardson number, and buoyancy length. The advantages of DA analysis over
turbulent kinetic energy (TKE), its component variances, FFT spectra, and
self-similar fractals are also discussed in terms of local versus global
basis functions, dimensional suitability, noise, algorithmic complexity,
and other factors. DA was found to be the only measure capable of reliably
distinguishing the wave from turbulence.http://archive.org/details/multifractalanal00decaLieutenant, United States NavyApproved for public release; distribution is unlimited
A self-affine multi-fractal wave turbulence discrimination method using data from single point fast response sensors in a nocturnal atmospheric boundary layer
We present DA, a self-affine, multi-fractal which may become the first routine wave/turbulence discriminant for time series data. Using nocturnal atmospheric data, we show the advantages of D A over self-similar fractals and standard turbulence measures such as FFTs, Richardson number, Brunt-Vaisala frequency, buoyancy length scale, variances, turbulent kinetic energy, and phase averaging. DA also shows promise in resolving "wave-break" events. Since it uses local basis functions, DA may be an ideal tool to detect intermittent turbulence, coherent structures, and discrete wave trains in general. DA may also be a measure of chaos in general.U.S. Air Force, Space Division, Los Angeles, CAhttp://archive.org/details/selfaffinemultif00kamaMPIR FY76169100412NAApproved for public release; distribution is unlimited