Batch

Progress on plasmid-based (pDNA) vaccines requires simpler and efficient cultivation techniques for their production. A prevalent problem in the cultivation of Escherichia coli (the main host for pDNA vaccines production) is the aerobic production of acetate. In this work, a metabolically engineered Escherichia coli strain with strongly reduced acetate formation was tested for the production of a plasmid vaccine at

This paper presents a batch classifier that splits a dataset into tree branches depending on the category type. It has been improved from the earlier version and fixed a mistake in the earlier paper. Two important changes have been made. The first is to represent each category with a separate classifier. Each classifier then classifies its own subset of data rows, using batch input values to create the centroid and also represent the category itself. If the classifier contains data from more than one category however, it needs to create new classifiers for the incorrect data. The second change therefore is to allow the classifier to branch to new layers when there is a split in the data, and create new classifiers there for the data rows that are incorrectly classified. Each layer can therefore branch like a tree - not for distinguishing features, but for distinguishing categories. The paper then suggests a further innovation, which is to represent some data columns with fixed value ranges, or bands. When considering features, it is shown that some of the data can be classified directly through fixed value ranges, while the rest must be classified using a classifier technique and the idea allows the paper to discuss a biological analogy with neurons and neuron links. Tests show that the method can successfully classify a diverse set of benchmark datasets to better than the state-of-the-art.

A new discretization for simultaneous aggregation, breakage, growth and nucleation is presented. The new discretization is an extension of the cell average technique developed by the authors [J. Kumar, M. Peglow, G. Warnecke, S. Heinrich, and L. Mörl. Improved accuracy and convergence of discretized population balance for aggregation: The cell average technique. Chemical Engineering Science 61 (2006) 3327–3342.]. It is shown that the cell average scheme enjoys the major advantage of simplicity for solving combined problems over other existing schemes. This is done by a special coupling of the different processes that treats all processes in a similar fashion as it handles the individual process. It is demonstrated that the new coupling makes the technique more useful by being not only more accurate but also computationally less expensive. At first, the coupling is performed for combined aggregation and breakage problems. Furthermore, a new idea that considers the growth process as aggregation of existing particle with new small nuclei is presented. In that way the resulting discretization of the growth process becomes very simple and consistent with first two moments. Additionally, it becomes easy to combine the growth discretization with other processes. The new discretization of pure growth is a little diffusive but it predicts the first two moments exactly without any computational difficulties like appearance of negative values or instability etc. The numerical scheme proposed in this work is consistent only with the first two moments but it can easily be extended to the consistency with any two or more than two moments. Finally, the discretization of pure and coupled problems is tasted on several analytically solvable problems.A numerical scheme for solving a general one-dimensional population balance equation is developed. It is shown that the scheme is simple to use and produces very accurate results of number density as well as its moments.

Most of systems using a large DBMS have been
using disk-based storages consisting of hard disk
drives. Recently, flash memory storages have
appeared, which have great advantages like low
access latency, low power consumption, light
weight and shock resistance. These flash memory
storages have gradually been successes as an
alternative storage of traditional hard disk drives.
However, because it is still a big price gap between
the hard disk and flash memory device, they’re still
using hard disk-based storages. Also systems to
perform online transactions and batch jobs at the
same time have performed batch jobs on a small
online transaction time because of poor
performance. Therefore, if we use flash memory
devices and hard disk drivers with, it will be very
efficient in terms of price, performance and
reliability. In addition, it is possible to shorten the
recovery time of DBMS. This paper proposes to
move the REDO logs and ARCHIVE logs on flash
memory storage device appropriately depending on
the operating and working environments. By
utilizing a small amount of flash memory devices,
the performance of batch jobs has been increased to
40-80%, DBMS recovery time was reduced to 5-
8%.

The multivessel batch column consists of a reboiler, several column sections, intermediate vessels and a condenser vessel. This configuration provides a generalization of previously proposed batch-distillation schemes, including the inverted column and the middle-vessel column. The total reflux operation of the multivessel batch-distillation column was presented recently, and the main contribution of this article is to propose a simple feedback control strategy for its operation. We propose to adjust the vessel holdups indirectly by manipulating the reflux flow out of each vessel to control the temperature at some location in the column section below. The feasibility of this strategy is demonstrated by simulations.

Vero cells were grown adherent to microcarriers (Cytodex 1; 3 g L(-1)) using animal component free media in stirred-tank type bioreactors. Different strategies for media refreshment, daily media replacement (semi-batch), continuous media replacement (perfusion) and recirculation of media, were compared with batch cultivation. Cell densities increased using a feed strategy from 1×10(6) cells mL(-1) during batch cultivation to 1.8, 2.7 and 5.0×10(6) cells mL(-1) during semi-batch, perfusion and recirculation, respectively. The effects of these different cell culture strategies on subsequent poliovirus production were investigated. Increased cell densities allowed up to 3 times higher D-antigen levels when compared with that obtained from batch-wise Vero cell culture. However, the cell specific D-antigen production was lower when cells were infected at higher cell densities. This cell density effect is in good agreement with observations for different cell lines and virus types. From t...

On inflamed endothelium the cell surface protein E-selectin isexpressed which supports the initial process of attachment –capturing and rolling of leukocytes. A recombinant CHO cell linesecreting a soluble E-selectin-IgG chimera was cultivated competitively under serum free conditions in three different bioreactor systems: a 1 l Super-Spinner, a 2 l stirred tank bioreactor equipped with a spinfilter, and a 100 l stirred tankbioreactor. In the smallest system 25.4 mg E-selectin-IgG wereproduced in 62 days using a repeated batch process whileachieving a maximal viable cell density of 3.7 × 106 cells ml-1. Using continuous perfusion mode a total amount of35.2 mg were produced with a maximal viable cell density of1.65 × 107 cells ml-1 in the 2 l bioreactor within 29 days. Large scale cultivation in a 100 l stirred tankbioreactor yielded 105.6 mg in three batches with a maximal viable cell density of 9.7 × 105 cells ml-1 within 15 days. After removal of the cells by continuous centrifugation and a depth filter clearance step, the supernatants were concentrated via ultra filtration. Purificationwas performed by affinity chromatography with rProtein A. Integrity of the E-selectin-IgG protein was checked with SDS PAGE. Its activity was verified in a cellular adhesion assay performed with HL-60 cells and a recombinant CHO cell line expressing membrane-anchored E-selectin constitutively, and E-selectin expressing HUVECs, respectively. Soluble E-selectin-IgG was used to block adhesion to these cell layerscompetitively. A concentation of 18.8 and 37.5 μg ml-1was sufficient to reduce the amount of adhering HL-60 cells to 50% on CHO and HUVEC layers, respectively.

This paper proposes an extension of Batches Petri Nets by a new definition of the batch place called Bi-parts Batch place (BBplace). The flow-density equations that govern the dynamics of controllable batches inside a BB-place is now defined by a triangular relation. To take into account controlled events, the behaviors of batches are discussed according to a variation of speeds and of maximum flows. The switching dynamics of controllable batches is defined on three behaviors: free, congestion and decongestion behaviors. We also propose the computation of the instantaneous firing flow vector associated with continuous and batch transitions thanks to a resolution of a linear programming problem. An example of traffic road illustrates the novel extensions proposed in this paper.

Batch ethanol fermentations from sweet sorghum juice by Saccharomyces cerevisiae NP 01 were carried out in a 500 ml air-locked Erlenmeyer flask under very high gravity (VHG) and static conditions. The maximum ethanol production efficiency was obtained when 9 g l-1 of yeast extract was supplemented to the juice. The ethanol concentration (P), productivity (Qp) and yield (Yp/s) were 120.24 ± 1.35 g l-1, 3.01 ± 0.08 g l-1 h-1 and 0.49 ± 0.01, respectively. Scale up ethanol fermentation in a 5-litre bioreactor at an agitation rate of 100 rev min-1 revealed that P, Qp and Yp/s were 139.51 ± 0.11 g l-1, 3.49 ± 0.00 g l-1 h-1 and 0.49 ± 0.01, respectively, whereas lower P (119.53 ± 0.20 g l-1) and Qp (2.13 ± 0.01 g l-1 h-1) were obtained in a 50-litre bioreactor. In the repeated-batch fermentation in the 5-litre bioreactor with fill and drain volume of 50 % of the working volume, lower P and Qp were observed in the subsequent batches. P in batch 2 to 8 ranged from 103.37 ± 0.28 to 109.53 ±...

This paper reports investigations carried out to determine the optimum culture conditions for the production of hydrogen with a recently isolated strain Clostridium butyricum CWBI1009. The production rates and yields were investigated at 30° C in a 2.3 L bioreactor operated ...