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The preceding chapters describe the various efforts, initiatives and policy attempts to realise transformation in the South African higher education system from 1994 up to 2000. Chapter 12 (New South African Realities) is to some extent a summary assessment of the findings and discussions of chapters 4 to 11. As these chapters show, and as we will argue here, transformation in higher education was seen by politicians and laymen, policy specialists and ordinary people as an indissoluble part of moving away from apartheid as a state form to a more open, inclusive, equitable and democratic society. This book describes how the transformation project was launched, with great acclaim, consensus and fanfare – through a series of founding documents such as the National Education Policy Initiative (NEPI, 1993), the ANC Policy Document (Centre for Education Policy Development, 1994), the report of the National Commission on Higher Education (NCHE, 1996), and even the first Higher Education White Paper of 1997 – only to seem to veer off track. A loss of course was detected in at least three areas. First, it seemed as if, after 1997, the policy process gradually became less participatory and democratic, and it even seemed to some that we were returning to something of a top-down style of policy imposition reminiscent of an earlier era. Secondly, it seemed as if the state was forsaking the values of equity and social justice in favour of the values of efficiency, effectiveness and responsiveness. Thirdly, even where policy had been implemented as intended (in the National Student Financial Aid Scheme [NSFAS], for example), it was producing effects different from the ones expected and desired. What was producing these contrary effects? Why had the transformation project in higher education come to be so widely seen as an unpleasant surprise and distasteful disappointment?

Caching, one of the oldest ideas in computer science, often improves performance and sometimes improves availability [1, 3]. Previous uses of caching have focused on data content. It is the presence of a local copy of data that reduces access latency and masks server or network failures. This position paper puts forth the idea that it can sometimes be useful to merely cache knowledge sufficient to recognize valid data. In other words, we do not have a local copy of a data item, but possess a substitute that allows us to verify the content of that item if it is offered to us by an untrusted source. We refer to this concept as caching trust.Mobile computing is a champion application domain for this concept. Wearable and handheld computers are constantly under pressure to be smaller and lighter. However, the potential volume of data that is accessible to such devices over a wireless network keeps growing. Something has to give. In this case, it is the assumption that all data of potential interest can be hoarded on the mobile client [1, 2, 6]. In other words, such clients have to be prepared to cope with cache misses during normal use. If they are able to cache trust, then any untrusted site in the fixed infrastructure can be used to stage data for servicing cache misses --- one does not have to go back to a distant server, nor does one have to compromise security. The following scenario explores this in more detail.

Many have written about the challenges that industrial research organizations face in trying to transfer the technology they create to other organizations. Research pursues a long and winding road from the proof of concept of a technology in the lab to the adoption of that technology by others and its use for corporate benefit. To follow the road to its end requires persistence, determination, flexibility, and (when, as is often the case, the road ends short of the destination) good humor. In this short paper, I offer a personal recollection of a part of one such journey — one in which the destination reached wasn’t the one originally sought. The Road

The purpose of this short paper is to remind the European star formation community, and more specifically the European young star clusters community, of the great potential of the VLT and to encourage the young European astronomers to make more and better use of it. Three classical examples of very young star clusters at 500 pc, 6.5 kpc, and 55 kpc (the Orion Nebula Cluster, NGC 3603 in the Carina arm, and R136 in the LMC) are chosen to illustrate the resolving power of the VLT in direct imaging mode, adaptive optics mode, and interferometric mode. The VLT with its high spatial resolution modes can be used as an astronomical microscope, as it were, with a zoom factor of 10 to 100.

The grinding system of paper machine rolls is studied. The MDOF model with double time delays is used to describe the dynamical behavior of the system. By analyzing the simplified linear and non-linear models the stability characteristics of the system has been investigated by different stability methods. Numerical simulation results are used to illustrate stability behaviors of the models.

This short paper surveys methods for planar shape smoothing and processing and planar shape recognition invariant under viewing distortions and even partial occlusions. It is argued that all the results available in the literature on these problems implicitly follow from successfully addressing two basic problems: invariant location of points with respect to a given shape (a given set of points in the plane) and invariant displacement of points with regard to the given shape.

The aim of the KCM (Knowledge Crunching Machine) project was to study how to speed-up Prolog, and more generally Logic Programming, through hardware support at the processor level. An experimental approach was taken, which resulted in the design and implementation of a real system, hardware and software. This short paper outlines the key features of the system as well as the main conclusions which can be drawn from the project.

The paper deals with the factors affecting the processes of nitrification and denitrification in wastewater treatment plants. The factors are e.g. sludge age, sludge load, retention period, temperature, pH, etc. The differences in efficiency of the nitrification and denitrification processes and energy demand are compared for a variety of types of wastewater treatment plant.

Aims The diagnostic value of natriuretic peptides in asymptomatic patients at risk for diastolic or systolic HF is controversial. We tested (1) the prevalence of preclinical LV dysfunction in an at-risk cohort; (2) the diagnostic accuracy of natriuretic peptides alone or in combination with clinical parameters for predicting asymptomatic left ventricular systolic or diastolic dysfunction. Methods 542 primary care patients (mean age 63 ± 11 years, 42% female) without prediagnosed HF, but with risk factors for left ventricular dysfunction, underwent thorough cardiological workup, including echocardiography and analysis of natriuretic peptides. Results 23 patients (4%) showed reduced systolic function (EF

In contrast to extracellular plaque and intracellular tangle pathology, the presence and relevance of intraneuronal Aβ in Alzheimer’s disease (AD) is still a matter of debate. Human brain tissue offers technical challenges such as post-mortem delay and uneven or prolonged tissue fixation that might affect immunohistochemical staining. In addition, previous studies on intracellular Aβ accumulation in human brain often used antibodies targeting the C-terminus of Aβ and differed strongly in the pretreatments used. To overcome these inconsistencies, we performed extensive parametrical testing using a highly specific N-terminal Aβ antibody detecting the aspartate at position 1, before developing an optimal staining protocol for intraneuronal Aβ detection in paraffin-embedded sections from AD patients. To rule out that this antibody also detects the β-cleaved APP C-terminal fragment (β-CTF, C99) bearing the same epitope, paraffin-sections of transgenic mice overexpressing the C99-fragment were stained without any evidence for cross-reactivity in our staining protocol. The staining intensity of intraneuronal Aβ in cortex and hippocampal tissue of 10 controls and 20 sporadic AD cases was then correlated to patient data including sex, Braak stage, plaque load, and apolipoprotein E (ApoE) genotype. In particular, the presence of one or two ApoE4 alleles strongly correlated with an increased accumulation of intraneuronal Aβ peptides. Given that ApoE4 is a major genetic risk factor for AD and is involved in neuronal cholesterol transport, it is tempting to speculate that perturbed intracellular trafficking is involved in the increased intraneuronal Aβ aggregation in AD. Electronic supplementary material The online version of this article (doi:10.1007/s00401-010-0666-1) contains supplementary material, which is available to authorized users.

Off-label drug use in paediatrics is associated with an increased risk of adverse drug reactions. Any risk–benefit analysis has to be based on value judgments that should include parents' views. However, nothing is known so far about the parents' perspective on this critical issue. Therefore, a quantitative survey with parents of healthy and chronically ill children was carried out (n = 94). Knowledge about the practise of off-label use is generally poor in both groups. Surprisingly, this is also true for the parents of children with chronic disease. Nine percent of the parents of chronically ill children and 20% of the parents of healthy children would refuse treatment with an off-label drug. Parents who have poor knowledge about the practise of off-label use tend to refuse to volunteer their child for study participation. Therefore, the information of parents on the off-label use of drugs is important to meet ethical standards and to increase the parents' acceptance of medical studies with children. peerReviewed

Linkage disequilibrium was investigated in canola quality winter rapeseed to analyze (1) the prospects for whole-genome association analyses and (2) the impact of the recent breeding history of rapeseed on linkage disequilibrium. A total of 845 mapped AFLP markers with allele frequencies ≥0.1 were used for the analysis of linkage disequilibrium in a population of 85 canola quality winter rapeseed genotypes. A low overall level of linkage disequilibrium was found with a mean r2 of only 0.027 over all 356,590 possible marker pairs. At a significance threshold of P = 2.8 × 10−7, which was derived by a Bonferroni correction from a global α-level of 0.1, only 0.78% of the marker pairs were in significant linkage disequilibrium. Among physically linked marker pairs, the level of linkage disequilibrium was about five times higher with more than 10% of marker pairs in significant linkage disequilibrium. Linkage disequilibrium decayed rapidly with distance between linked markers with high levels of linkage disequilibrium extending only for about 2 cM. Owing to the rapid decay of linkage disequilibrium with distance association analyses in canola quality rapeseed will have a significantly higher resolution than QTL analyses in segregating populations by interval mapping, but much larger number of markers will be necessary to cover the whole genome. A major impact of the recent breeding history of rapeseed on linkage disequilibrium could not be observed. Electronic supplementary material The online version of this article (doi:10.1007/s00122-009-1221-0) contains supplementary material, which is available to authorized users.

To determine if NMDA receptor alterations are present in the cerebellum in schizophrenia, we measured NMDA receptor binding and gene expression of the NMDA receptor subunits in a post-mortem study of elderly patients with schizophrenia and non-affected subjects. Furthermore, we assessed influence of genetic variation in the candidate gene neuregulin-1 (NRG1) on the expression of the NMDA receptor in an exploratory study. Post-mortem samples from the cerebellar cortex of ten schizophrenic patients were compared with nine normal subjects. We investigated NMDA receptor binding by receptor autoradiography and gene expression of the NMDA receptor subunits NR1, NR2A, NR2B, NR2C and NR2D by in situ hybridization. For the genetic study, we genotyped the NRG1 polymorphism rs35753505 (SNP8NRG221533). Additionally, we treated rats with the antipsychotics haloperidol or clozapine and assessed cerebellar NMDA receptor binding and gene expression of subunits to examine the effects of antipsychotic treatment. Gene expression of the NR2D subunit was increased in the right cerebellum of schizophrenic patients compared to controls. Individuals carrying at least one C allele of rs35753505 (SNP8NRG221533) showed decreased expression of the NR2C subunit in the right cerebellum, compared to individuals homozygous for the T allele. Correlation with medication parameters and the animal model revealed no treatment effects. In conclusion, increased NR2D expression results in a hyperexcitable NMDA receptor suggesting an adaptive effect due to receptor hypofunction. The decreased NR2C expression in NRG1 risk variant may cause a deficit in NMDA receptor function. This supports the hypothesis of an abnormal glutamatergic neurotransmission in the right cerebellum in the pathophysiology of schizophrenia. peerReviewed

Purpose To evaluate toxicity of radiochemotherapy schedule using daily-low-dose-cisplatin in radiochemotherapy of locally-advanced head-and-neck-cancer (HNSCC). Methods and patients From October 2003 to October 2006, 50 patients with HNSCC (stage III/IVA/IVB) were treated. In 32 patients, surgery and adjuvant radiotherapy(64 Gy), in 18 patients definitive radiotherapy(70 Gy) was performed. Low-dose-cisplatin was applied concomitantly (6 mg/m2/every radiotherapy-day). Results Acute toxicity ≥grade 3 was observed in 22 patients (11 patients mucositis/dysphagia, 7 hematologic toxicity, 4 mucositis/dysphagia/hematologic toxicity). 90% of our patients received >80% of the planned cumulative chemotherapy dose, 94% the intended dose of radiotherapy. After median follow-up of 24.2 months, 3-year overall survival and loco-regional control rates were 67.1 and 78%. During follow-up, chronic toxicity ≥grade 3 (xerostomia, subcutaneous fibrosis, or lymphedema) was observed in nine patients. Conclusion We found chemoradiation with daily-low-dose-cisplatin to be feasible with advantage of low acute and chronic toxicity. Therefore, use of low-dose-cisplatin should be evaluated in future clinical trials. peerReviewed

Since the first discovery of the presence of acrylamide in a variety of food products in April 2002, numerous methods have been developed to determine the acrylamide monomer in heat-treated carbohydrate-rich food. These detection methods are mainly MS-based, coupled with a chromatographic step using LC or GC. The Food Chemistry Institute (LCI) of the Association of the German Confectionery Industry (BDSI) therefore established a detection method by means of aqueous extraction plus a cleaning step and LC-MS/MS detection, making great efforts to ensure internal and external validation. Citing potato crisps as an example, we will in the following show how the German manufacturing companies have gone to great pains to reduce acrylamide levels in their products.

An integrated approach is described with respect to acrylamide minimization in heated foodstuffs. All relevant variables have to be considered and the main focus is on maintaining the expected product quality. The role of the processes at the interface between product and heating medium during processing is characterized for the case of frying operations. Examples of parameters influencing these processes with respect to minimizing acrylamide and maintaining product quality (e.g. brown color) are described. First, the local distribution of acrylamide in a French fries type model food was investigated. Lowering water activity at the surface of French fries before frying contributes to a reduction of acrylamide without lowering product quality. Both pre-drying of the potato sticks before frying and an increasing of salt concentration at the product surface by coating with a salt solution showed positive effects. Additionally, it was demonstrated by simulation that combined effects of these measurements may enable a reduction of up to 80% in the acrylamide content.

In vitro culture is a semi-closed system that aseptically provides oxygen, water, organic carbon source (and/or CO2 and light), nutrients, and plant growth regulators (PGR), at a controlled temperature. A traditional view of plant tissue culture involves placing a small piece of tissue on the gelled-media surface, in a jar, plate or tube, and allows exponential growth unfettered by lack of resource in a uniform microenvironment. Many reports summarized in this volume show increased productivity (per plant, unit area or time) were achieved with larger vessels of liquid medium yielding greater numbers and / or larger plants. Liquid systems that improve distribution of dissolved nutrients, water and oxygen, in the vessel stimulate growth of plant tissues. Simplicity, cost and ergonomic factors are human constraints imposed on designs intended for commercial use. This chapter describes a hybrid micropropagation process that invokes features of semi-solid gel and bioreactor technology. The agitated, thin-film system (or rocker) uses large, rigid rectangular vessels in a slow pitching motion to intermittently wet and aerate plantlets [1] (see Figure 1). Economy of scale was optimized for the twodimensional growth surface area in the vessel. Gentle oxygenation of liquid media was similar to wave machines Eibl and Eibl describe for cell and tissue culture in Part 2 of this volume. Shoot surfaces, intermittently wet or dry in a large headspace, accumulate large quantities of solutes from media resulting in high shoot quality similar to temporary immersion systems. Vessel and culture room designs differ from conventional micropropagation, or the bioreactors discussed in other chapters of Part 2. The first section of this chapter discusses nutrients and heterotrophic growth in agar and liquid;the secondsectioncomparesefficiencyof agitated,thin-film processwith agar-based media system; and third one lists designconsiderations for the vessel and culture shelves in the growth room during scale-up. Comparisons will be drawn to agar-gelled media in small round jars, typical of many micropropagation protocols using semi-solid media.

According to the results of the investigations, the following conditions are recommended for the clonal propagation of S. albida by cutting. 1. Good permeability of water is required for the cutting bed. 2. The cutting bed should be sealed with a clear plastic film to keep high relative humidity inside. 3. Washed large-grain river sand is suitable as a culture medium, due to its good porosity and permeability for developing a sound root system. 4. Irrigation frequency should be kept to a minimum, due to the sensitivity of S. albida against excessive water. 5. Cutting stems should be prepared by cutting between nodes. 6. Although the most suitable light intensity has not yet been found for rooted cuttings, the inside of the nursery house should have a bright-light intensity. 7. The effect of rooting hormones is clear in the case of insufficient conditions for rooting, such as incomplete sealing and/or insufficient light intensity etc.

The preceding chapters of this book discuss scientific research results on natural and managed oak forests growing in the highlands of the American Tropics. Chapter authors highlight evolutionary, ecological and socioeconomic aspects of specific oak forests and identify existing gaps in our understanding. Their work and studies published elsewhere forms the basis for this chapter’s overview of the current state of knowledge on ecological patterns and processes which determine the structure and functioning of these magnificent forests. The increasingly important human use and much needed conservation of these biodiverse and threatened habitats are dealt with as well. Cross-cutting trends and issues are discussed and conclusions drawn. Neotropical montane oak forests are a special type of tropical montane forests (Kappelle 2004), in which tall oak trees (Quercus) dominate a 30to 60-m-high forest canopy, often in pure stands or mixed with pines (Pinus) or other predominant trees. Though Neotropical oak forest history, structure, species diversity, species interactions, ecosystem functioning, post-disturbance recovery, and human use may vary considerably over short geographical ranges, regional trends are now becoming evident. Research presented in this book clearly illustrates these large-scale trends. The following sections in this chapter synthesize our knowledge for each of these trends and themes.

The different silvicultural techniques for establishing big-leaf mahogany plantations have been well documented, but these methods frequently take little account of the long-term development of stands or subsequent rotations and cannot properly be called silvicultural systems. As existing plantations begin to mature, the need to consider establishing the next rotation grows, and, therefore, the need to adopt a suitable silvicultural system. Where plantations of big-leaf mahogany have begun to regenerate naturally, the traditional system of clear-cutting and replanting may not be appropriate. Natural regeneration has the advantages of reducing nursery and establishment costs and possibly the extent of damage by shoot borer (Hypsipyla sp.). Early attempts to apply a single tree selection system to big-leaf mahogany plantations were unsuccessful, but recent plans to adopt a modified uniform shelterwood system in Sri Lanka and a group selection system in St. Lucia have been more carefully developed. The proposed systems are described in detail. Successful long-term management of big-leaf mahogany plantations depends on choosing a system that accommodates both the light requirements of the species and key local constraints under which plantation managers are operating. Local constraints should be carefully considered before a silvicultural system is adopted.

A typical batch process may be subdivided into: a) continuous sterilization of culture medium b) aeration and agitation in bioreactor vessel c) ancillary operations and equipment.

This chapter describes Environment Canada’s method entitled Biological Test Method: Test for Measuring the Inhibition of Growth Using the Freshwater Macrophyte, Lemna minor (EC, 1999). Research has lead to minor changes in the methodology that are described where appropriate. Applications of the method are also described herein. The L. minor growth inhibition test is a toxicity test carried out in replicate test vessels containing 100 mL of test solution and two 3-frond L. minor plants, at the end of which the effects of contaminants on Lemna growth are determined. It can be used alone or as part of a test battery to determine and monitor the toxic effects of discrete substances or complex mixtures that could be harmful to aquatic life in freshwater ecosystems. Results of these toxicity tests can be used as part of a weight-of-evidence approach, to determine the need for control of discharges and to set effluent standards (EC, 1999). The L. minor growth inhibition test measures: (a) increased number of fronds; and (b) dry weight (as an indication of growth) at the end of the test. Various sample types can be evaluated using this method, including: (1) freshwater industrial or urban effluents, elutriates, or leachates; (2) single chemicals, commercial products, or known mixtures of chemicals; and (3) freshwater surface or receiving waters. The small size, structural simplicity and rapid growth of L. minor are some of the characteristics that make them advantageous for use in laboratory toxicity tests. In addition, the cultures are easily maintained in the laboratory, test results are reproducible, and the method is cost effective.

The test method described below can be employed on its own, or as part of a battery of tests approach, to estimate the phytotoxicity potential of diverse types of liquid samples. Because it is conducted in a 96-well microplate format, the technique is simple and offers other advantages which include cost-effectiveness and spacesaving features. It is theoretically applicable to any liquid. Testing can be undertaken, for example, with samples representing the following media: (1) domestic and industrial wastewaters, treated or untreated; (2) surface, groundwater or leachates; (3) sediment interstitial waters; (4) any chemical that is soluble in water; (5) any water-insoluble chemical that can be rendered soluble by means of an organic solvent or other techniques (e.g., sonication or emulsification).

Due to the frequent use of domestic sewage sludges as organic additives to soils with low humus content, the chemical characteristics of the extractable polymers from composted and uncomposted sludges were described.

Metabolic activities of some anaerobic Clostridia strains result in the production of solvents, acetone, butanol, ethanol, iso-propanol etc., and hydrogen gas, all of interest to industry. Hexose sugars are readily utilized for this purpose, so are hexose- and pentose-based polysaccharides. Pentoses can also be utilized, however, the production rates observed are somewhat lower. Revived interest in the process is currently gaining momentum and new techniques of genetic manipulation of microorganisms coupled together with novel bioprocess technology, solvent recovery techniques, and minicomputer process control/optimization, offer a promise of resulting in an efficient and competitive process modification. Wood, agricultural residues and waste liquors constitute a cheap source of renewable raw materials for industrial solvent production.

The presented material concerns the theoretical basis for obtaining high-quality active dry biopreparations. It deals with the present understanding of anabiosis, contains data on yeast resistance against dehydration and the limits for preserving the viability of microorganisms in anabiosis. The process of water transport in yeast biomass during dehydration is discussed.

Resource and technological aspects of ethanol production are considered. Conversion of lignocellulosic substrates to ethanol via thermophilic bacteria is then addressed, with particular emphasis on evaluation from an engineering perspective.

The diminishing one-way resources must be replaced by renewable, plentiful organic materials such as cellulose. Enzymatic hydrolysis of cellulose has been intensively studied in recent years, since acid hydrolysis has not proved to be economically feasible. In spite of the abundance of cellulose, it is not very easy to find suitable cellulosic materials that could be collected from a limited area and would be cheap enough, taking into account collecting, transport, handling, and storage costs. The correct choice of material depends on local conditions. For example, sugarcane bagasse would be useful in certain areas.

The phenomenon aggregation of anaerobic bacteria gives an opportunity to speed up the digestion rate during methanogenesis. The aggregates are mainly composed of methanogenic bacteria which convert acetate and H2/CO2 into methane. Other bacteria are also included in the aggregates but their concentration is rather small. The aggregates may also be formed during acetogenesis or even hydrolysis but such aggregates are not stable and disrupt quickly when not fed. A two stage process seems to be suitable when high concentrated solid waste must be treated.

Cellulose was undoubtedly man's first fuel, being the major component of wood for his fires. Therefore, when we consider cellulose as a “novel” energy source we have more indirect use in mind, such as its conversion to synthetic fuels (Huge, 1968) and to food (Meller, 1969).

Production of ethanol from sugar (hexoses) and starchis carried out by a well developed technology. Production of ethanol from lignocellulosic materials is more difficult, requires several process steps, and is as yet in the development stage.

Methyl bromide is both a naturally produced chemical and a man-made chemical. Methyl bromide is naturally produced by oceans, biomass burning, and plants. Anthropogenic methyl bromide is produced intentionally by man as a fumigant and unintentionally by combustion processes involving leaded gasoline and human-caused biomass burning. Approximately 70% of man-made methyl bromide is used as a fumigant; of that, about 75% is used is for pre-plant soil treatments, 21% for commodity treatments, and 3% for structural treatments. Because of international government restrictions on production and consumption, the use of methyl bromide is currently limited to 1991 levels. Because a percentage of methyl bromide is degraded during use, emissions do not equal consumption. It is estimated that approximately 63,418 metric tons of methyl bromide are emitted per year from all anthropogenic sources.

The main sources of drinking water are often polluted by industrial and municipal chemicals. Water treatment plants reduce the concentrations of harmful chemicals in water to a safe level and mandatory disinfection renders water non-hazardous from a bacteriological standpoint. However, conventional water treatment technologies using chlorine result in formation of disinfectant by-products. They have been proved to be strongly carcinogenic. Additionally, water quality deteriorates through the distribution networks. This is due to reproduction and decay of different microorganisms inside the water mains. Thus, at the endpoints of water networks, the concentrations of trihalomethanes, surface-active substances, iron compounds, etc., may exceed the maximum permissible concentration (MPC) by several times, and those of heterotrophs — up to hundred times.

Novel biofilm reactor systems, a parallel trickling biofilter (TBF) system and a two-stage continuous stirred tank reactor (CSTR)/trickling biofilter system, were developed and operated for long-term continuous treatment of gas-phase trichloroethylene (TCE) by the bacterium Burkholderia cepacia G4. The effects of trichloroethylene concentrations on reactor performances were analyzed. The critical trichloroethylene elimination capacities were determined to be 8.6 and 25.3 mg trichloroethylene l−1 d−1, respectively.

High product yield, product quality and stable reactor culture conditions are a key to economically viable pharmaceutical bioprocesses. Two types of culture methods for production of recombinant anti-HIV-antibody were applied within this study. The tested cell line was a DHFR- recombinant CHO cell line expressing anti-HIV antibodies (CHO-4E10; Polymun Scientific, Vienna, Austria).Cells were cultured in a perfused lab-scale fluidized bed Cytopilot Mini™ reactor (Amersham Biosciences, Uppsala, Sweden) attached to macroporous Cytoline 1™ (Amersham Biosciences, Uppsala, Sweden) microcarriers and as suspension cells in a pilot scale stirred tank bioreactor fed-batch process. Both processes were performed using protein-free media. The systems were compared in terms of cell growth, product yield and product quality. Both systems were equally well suited for production of the recombinant protein in terms of product yield and product quality, however demonstrating an economic advantage of the fluidized bed process.

Principles of oxygen consumption, oxygen transport, suspension, and mixing are discussed in the context of propagating aggregates of plant tissue in liquid suspension bioreactors. Although micropropagated plants have a relatively low biological oxygen demand (BOD), the relatively large tissue size and localization of BOD in meristematic regions will typically result in oxygen mass transfer limitations in liquid culture. In contrast to the typical focus of bioreactor design on gas–liquid mass transfer, it is shown that media-solid mass transfer limitations limit oxygen available for aerobic plant tissue respiration. Approaches to improve oxygen availability through gas supplementation and bioreactor pressurization are discussed. The influence of media components on oxygen availability are also quantified for plant culture media. Experimental studies of polystyrene beads in suspension in a 30-l air-lift and stirred bioreactors are used to illustrate design principles for circulation and mixing. Potential limitations to the use of liquid suspension culture due to plant physiological requirements are acknowledged.

The operative cycle in a pasta production plant is divided in four phases: a) receipt and storing of the raw material (floor), b) control and mixing of the raw material (floor), c) hvdratation and kneading of dough, extrusion and drying of the pasta, d) packing, palletization and final storing.

Reference GR-CEL-ARTICLE-2004-003doi:10.1007/s00128-004-0497-7View record in Web of Science Record created on 2005-07-15, modified on 2016-08-08