bluuebunny/crossref_metadata_2025 huggingface dataset:
Timing and Expression Level of Protein Kinase Cε Regulate the Megakaryocytic Differentiation of Human CD34 Cells
Authors: Gobbi Giuliana , Mirandola Prisco , Sponzilli Ivonne , Micheloni Cristina , Malinverno Chiara , Cocco Lucio , Vitale Marco
Published: June 2007

Protein kinase C (PKC)-mediated intracellular signaling participates in several key steps of hematopoietic cell differentiation. The ε isoform of PKC has been associated with erythroid differentiation as well as with the early phases of megakaryocytic (MK) lineage commitment. Here, we worked on the hypothesis that PKCε expression levels might be modulated during MK differentiation, with a specific role in the early as well as in the late phases of thrombopoiesis. We demonstrate that—at variance with the erythroid lineage development—PKCε is completely downmodulated in TPO-induced CD34 cells from day 6 onward. The forced expression of PKCε in the late phases of MK differentiation delays the phenotypic differentiation of progenitors likely via Bcl-xL upregulation. Moreover, tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), known as a negative regulator of early erythroid expansion, is not apoptogenic for thrombopoietin-induced CD34 cells, but rather accelerates their maturation. However, PKCε levels negatively interfere also with the effects of TRAIL in MK differentiation. PKCε can therefore be considered a signaling intermediate whose expression levels are finely tuned, with a virtually opposite kinetic, in erythroid versus megakaryocytic lineages, to adequately respond to the signaling requirements of the specific hematopoietic lineage.

Disclosure of potential conflicts of interest is found at the end of this article.
Novel Extracellular Matrix Structures in the Neural Stem Cell Niche Capture the Neurogenic Factor Fibroblast Growth Factor 2 from the Extracellular Milieu
Authors: Kerever Aurelien , Schnack Jason , Vellinga Dirk , Ichikawa Naoki , Moon Chris , Arikawa-Hirasawa Eri , Efird Jimmy T. , Mercier Frederic
Published: June 2007

The novel extracellular matrix structures called fractones are found in the lateral ventricle walls, the principal adult brain stem cell niche. By electron microscopy, fractones were shown to contact neural stem and progenitor cells (NSPC), suggesting a role in neurogenesis. Here, we investigated spatial relationships between proliferating NSPC and fractones and identified basic components and the first function of fractones. Using bromodeoxyuridine (BrdU) for birth-dating cells in the adult mouse lateral ventricle wall, we found most mitotic cells next to fractones, although some cells emerged next to capillaries. Like capillary basement membranes, fractones were immunoreactive for laminin β1 and γ1, collagen IV, nidogen, and perlecan, but not laminin-α1, in the adult rat, mouse, and human. Intriguingly, N-sulfate heparan sulfate proteoglycan (HSPG) immunoreactivity was restricted to fractone subpopulations and infrequent subependymal capillaries. Double immunolabel for BrdU and N-sulfate HSPG revealed preferential mitosis next to N-sulfate HSPG immunoreactive fractones. To determine whether N sulfate HSPG immunoreactivity within fractones reflects a potential for binding neurogenic growth factors, we identified biotinylated fibroblast growth factor 2 (FGF-2) binding sites in situ on frozen sections, and in vivo after intracerebroventricular injection of biotinylated FGF-2 in the adult rat or mouse. Both binding assays revealed biotinylated FGF-2 on fractone subpopulations and on infrequent subependymal capillaries. The binding of biotinylated FGF-2 was specific and dependent upon HSPG, as demonstrated in vitro and in vivo by inhibition with heparatinase and by the concomitant disappearance of N-sulfate HSPG immunoreactivity. These results strongly suggest that fractones promote growth factor activity in the neural stem cell niche.

Disclosure of potential conflicts of interest is found at the end of this article.
Expression of the p16INK4A Gene Is Associated Closely with Senescence of Human Mesenchymal Stem Cells and Is Potentially Silenced by DNA Methylation During In Vitro Expansion
Authors: Shibata Kotaro R. , Aoyama Tomoki , Shima Yasuko , Fukiage Kenichi , Otsuka Seiji , Furu Moritoshi , Kohno Yoshiki , Ito Kinya , Fujibayashi Shunsuke , Neo Masashi , Nakayama Tomitaka , Nakamura Takashi , Toguchida Junya
Published: June 2007

The precise biological characteristics of human mesenchymal stem cells (hMSCs), including growth regulatory mechanisms, have not yet been defined. Using 29 strains of hMSCs isolated from bone marrow, we have performed extensive analyses of the growth profiles of hMSCs in vitro. All 29 strains stopped proliferating with a mean population doubling (PD) of 28, although there was a considerable difference among strains. The mean telomere restriction fragment length of the cells passaged twice correlated well with the final number of PDs in each strain, suggesting the value of this measurement to be predictive of the growth potential of hMSCs. The expression level of the p16INK4A gene was associated closely with the PD number of each strain (p = .00000001). Most of the p16INK4A-positive cells were Ki67-negative and senescence associated β-galactosidase-positive, and the suppression of p16INK4A gene expression by small interfering RNA in senescent hMSCs reduced the number of senescent cells and endowed them with the ability to proliferate. Twenty-five of the 29 strains showed a steady gradual increase in the expression of p16INK4A. The remaining four strains (13.8%) showed different profiles, in which DNA methylation in the promoter region occurred in vitro. One of the four strains continued to proliferate for much longer than the others and showed chromosomal aberrations in the later stages. These results indicated p16INK4A to be a key factor in the regulation of hMSC growth, and, most importantly, careful monitoring of DNA methylation should be considered during the culture of hMSCs, particularly when a prolonged and extended propagation is required.

Disclosure of potential conflicts of interest is found at the end of this article.
Disruption of Apical-Basal Polarity of Human Embryonic Stem Cells Enhances Hematoendothelial Differentiation
Authors: Krtolica Ana , Genbacev Olga , Escobedo Carmen , Zdravkovic Tamara , Nordstrom Adam , Vabuena Diana , Nath Aneel , Simon Carlos , Mostov Keith , Fisher Susan J.
Published: June 2007

During murine development, the formation of tight junctions and acquisition of polarity are associated with allocation of the blastomeres on the outer surface of the embryo to the trophoblast lineage, whereas the absence of polarization directs cells to the inner cell mass. Here, we report the results of ultrastructural analyses that suggest a similar link between polarization and cell fate in human embryos. In contrast, the five human embryonic stem cell (hESC) lines displayed apical-basal, epithelial-type polarity with electron-dense tight junctions, apical microvilli, and asymmetric distribution of organelles. Consistent with these findings, molecules that are components of tight junctions or play regulatory roles in polarization localized to the apical regions of the hESCs at sites of cell-cell contact. The tight junctions were functional, as shown by the ability of hESC colonies to exclude the pericellular passage of a biotin compound. Depolarization of hESCs produced multilayered aggregates of rapidly proliferating cells that continued to express transcription factors that are required for pluripotency at the same level as control cells. However, during embryoid body formation, depolarized cells differentiated predominantly along mesenchymal lineage and spontaneously produced hematoendothelial precursors more efficiently than control ESC. Our findings have numerous implications with regard to strategies for deriving, propagating, and differentiating hESC.

Disclosure of potential conflicts of interest is found at the end of this article.
Adaptive Multiscale Finite-Volume Framework for Reservoir Simulation
Authors: Tchelepi H. A. , Jenny P. , Lee S. H. , Wolfsteiner C.
Published: June 2007

A multiscale finite-volume (MSFV) framework for reservoir simulation is described. This adaptive MSFV formulation is locally conservative and yields accurate results of both flow and transport in large-scale highly heterogeneous reservoir models. IMPES and sequential implicit formulations are described. The algorithms are sensitive to the specific characteristics of flow (i.e., pressure and total velocity) and transport (i.e., saturation). To compute the fine-scale flow field, two sets of basis functions - dual and primal - are constructed. The dual basis functions, which are associated with the dual coarse grid, are used to calculate the coarse scale transmissi-bilities. The fine-scale pressure field is computed from the coarse grid pressure via superposition of the dual basis functions. Having a locally conservative fine scale velocity field is essential for accurate solution of the saturation equations (i.e., transport). The primal basis functions, which are associated with the primal coarse grid, are constructed for that purpose. The dual basis functions serve as boundary conditions to the primal basis functions. To resolve the fine scale flow field in and around wells, a special well basis function is devised. As with the other basis functions, we ensure that the support for the well basis is local.

Our MSFV framework is designed for adaptive computation of both flow and transport in the course of a simulation run. Adaptive computation of the flow field is based on the time change of the total mobility field, which triggers the selective updating of basis functions. The key to achieving scalable (efficient for large problems) adaptive computation of flow and transport is the use of high fidelity basis functions with local support. We demonstrate the robustness and computational efficiency of the MSFV simulator using a variety of large heterogeneous reservoir models, including the SPE 10 comparative solution problem.
Fast Estimation of Connectivity in Fractured Reservoirs Using Percolation Theory
Authors: Masihi M. , King P. R. , Nurafza P.
Published: June 2007

Investigating the impact of geological uncertainty (i.e., spatial distribution of fractures) on reservoir performance may aid management decisions. The conventional approach to address this is to build a number of possible reservoir models, upscale them, and then run flow simulations. The problem with this approach is that it is computationally very expensive. In this study, we use another approach based on the permeability contrasts that control the flow, called percolation approach. This assumes that the permeability disorder of a rock can be simplified to either permeable or impermeable. The advantage is that by using some universal laws from percolation theory, the effect of the complex geometry which influences the global properties (e.g., connectivity or conductivity) can be easily estimated in a fraction of a second on a spreadsheet.

The aim of this contribution is to establish the percolation framework to examine the connectivity of fracture systems at a given finite observation scale in 2D and 3D. In particular, we use numerical simulation to show how the scaling laws of the connectivity derived originally for constant-length isotropic systems can be expanded to cover more realistic cases including fracture systems with anisotropy and fracture-length distribution. Finally, the outcrop data of mineralized fractures exposed on the southern margin of the Bristol Channel Basin was used to show that the predictions from the percolation approach are in agreement with the results calculated from field data but can be obtained very quickly. As a result, this may be used for practical engineering purposes for decision making.
Streamline Tracing on General Triangular or Quadrilateral Grids
Authors: Matringe Sébastien F. , Juanes Ruben , Tchelepi Hamdi A.
Published: June 2007

Streamline methods have received renewed interest over the past decade as an attractive alternative to traditional finite-difference (FD) simulation. They have been applied successfully to a wide range of problems including production optimization, history matching, and upscaling. Streamline methods are also being extended to provide an efficient and accurate tool for compositional reservoir simulation. One of the key components in a streamline method is the streamline tracing algorithm. Traditionally, stream-lines have been traced on regular Cartesian grids using Pollock's method. Several extensions to distorted or unstructured rectangular, triangular, and polygonal grids have been proposed. All of these formulations are, however, low-order schemes.

Here, we propose a unified formulation for high-order stream-line tracing on unstructured quadrilateral and triangular grids, based on the use of the stream function. Starting from the theory of mixed finite-element methods (FEMs), we identify several classes of velocity spaces that induce a stream function and are therefore suitable for streamline tracing. In doing so, we provide a theoretical justification for the low-order methods currently in use, and we show how to extend them to achieve high-order accuracy. Consequently, our streamline tracing algorithm is semi-analytical: within each gridblock, the streamline is traced exactly. We give a detailed description of the implementation of the algorithm, and we provide a comparison of low- and high-order tracing methods by means of representative numerical simulations on 2D heterogeneous media.
Carbon Dioxide Foam Rheology in Porous Media: A CT Scan Study
Authors: Du Dongxing , Zitha Pacelli L. J. , Uijttenhout Matthijs G. H.
Published: June 2007

Carbon dioxide (CO2) foam has been widely studied in connection with its application in enhanced oil recovery (EOR). This paper reports an experimental study concerning CO2 foam propagation in a surfactant-saturated Bentheim sandstone core and the subsequent liquid injection with the aid of X-ray computed tomography (CT). The experiments were carried out under various system backpressures. It is found that CO2 foam flows in a characteristic front-like manner in the transient stage and that the water saturation keeps at relatively high level at the outlet of the porous media because of CO2 solubility and capillary end effect. The subsequent surfactant solution injection shows a significant fingering behavior, accompanied by a low flow resistance over the core. It is also found that CO2 foam flow shows higher liquid saturation near the outlet and lower pressure drops under higher system backpressures. This can be attributed to the solubility of CO2 in the liquid phase. The results indicate the advantage of using foam in EOR processes such as water alternating foam (WAF), in which foam flow has higher sweep efficiency and stronger mobility control ability compared, for instance, to water alternating gas (WAG). Nevertheless, care should be taken during the water-injection stage in order not to favor the fingering.
Oxidation and mineralisation of substituted phenols by Fenton's reagent and catalytic wet oxidation
Authors: Santos A. , Rodriguez S. , Garcia-Ochoa F. , Yustos P.
Published: June 2007

Catalytic abatement of solutions of 1,000 mg/L in phenol, ortho and para nitrophenol and ortho and para cresols was acomplished by using two catalytic systems. Fenton's reagent was used at 50 °C by adding 10 mg/L of ferrous cation and different dosages of H2O2. The mixture was reacting isothermically in a batch way during 3 hours. Catalytic wet oxidation (CWO) was carried out by using a commercial Activated Carbon, Industrial React FE01606A, CWO runs were carried out in a fixed bed reactor (FBR) with concurrent upflow. Temperature and oxygen pressure of the reactor were set to 160 °C and 16 bar, respectively. While phenols are quicky oxidised by the Fenton reagent higher mineralisation was obtained in the CWO process.
Review of fundamentals and specific aspects of oxidation technologies in marine waters
Authors: Kornmueller A.
Published: June 2007

This review is based on the existing literature and on our experiences in the application of different oxidation processes in brackish water and seawater. The oxidation reactions of advanced oxidation processes (AOPs) and the formation of disinfection byproducts (DBPs) are considerably different in marine waters from well-known drinking, process and wastewater applications. In contrast, the major secondary oxidants are bromine species in marine waters, which might form the DBPs of concern bromate and bromoform. An efficient AOP application needs knowledge of the source water constitutions and the oxidant demand. Besides changes in the oxidants chemistry compared to fresh water, the great and seasonal variation of marine waters has to be considered in the process design. The complexity of oxidant reactions and formation of byproducts are only partially researched and known as yet. Hence, it is advisable to determine the characteristic and variation of the water source as well as its influence on each AOP in experiments prior to the process design.
The basics of oxidants in water treatment. Part B: ozone reactions
Authors: von Gunten U.
Published: June 2007

The oxidation of organic and inorganic compounds during ozonation can occur via ozone or OH radicals or a combination thereof. Ozone is an electrophile with a high selectivity. The reactions of ozone with inorganic compounds are typically fast and occur by an oxygen atom transfer reaction. Organic micropollutants are oxidised with ozone selectively. Ozone reacts mainly with double bonds, activated aromatic systems and non-protonated amines. The kinetics of direct ozone reactions depend strongly on the speciation (acid-base, metal complexation). The reaction of OH radicals with the majority of inorganic and organic compounds is nearly diffusion-controlled. The degree of oxidation by ozone and OH radicals is given by the corresponding kinetics and the ratio of the concentration of the two oxidants. Product formation from the ozonation of organic micropollutants has only been established for a few compounds. Numerous organic and inorganic ozonation disinfection/oxidation byproducts have been identified. The byproduct of main concern is bromate, which is formed in bromide-containing waters. A low drinking water standard of 10 μgL−1 has been set for bromate. In certain cases (bromide >∼50 μgL−1), it may be necessary to use control measures to lower bromate formation (lowering of pH, ammonia addition, chlorination-ammonia process).
The basics of oxidants in water treatment. Part A: OH radical reactions
Authors: von Sonntag C.
Published: June 2007

The Advanced Oxidation Processes (AOPs) are based on the reactions of the highly reactive •OH radicals. The formation of •OH by the various AOPs and their ensuing reactions are reviewed.
Coupled photochemical-biological system to treat biorecalcitrant wastewater
Authors: Bacardit J. , García-Molina V. , Bayarri B. , Giménez J. , Chamarro E. , Sans C. , Esplugas S.
Published: June 2007

The aim of the present work is to study a coupled system to treat biorecalcitrant wastewaters. The combination consists of an advanced oxidation process (AOP) named photo-Fenton (Ph-F), which is a photochemical treatment and a sequencing batch biofilter reactor (SBBR). The synthetic wastewater used to optimise this process is a solution of 200 ppm of 4-chlorophenol (4-CP). The first part of the work is the study of the biodegradability enhancement achieved by the photochemical process, measured as the ratio between the biochemical oxygen demand (BOD5) and the chemical oxygen demand (COD). The second step is the start-up and optimisation of the biological process. The results showed that it is necessary to severely treat the toxic solution (with 500 ppm of [H2O2]0) in order to achieve more than 90% of TOC removal in the whole process. The photochemical and biological treatments lasted 50 minutes and 24 hours, respectively.
Catalytic action of goethite in the oxidation of 2-chlorophenols with hydrogen peroxide
Authors: Lin Y.-T. , Lu M.-C.
Published: June 2007

The use of goethite and hydrogen peroxide was recently found to effectively oxidise organic compounds. This research was to investigate the effect of adsorption, pH, Fe2 +  and Fe3 +  on 2-CP oxidation. Results indicated that 2-CP can be decomposed with hydrogen peroxide catalysed by goethite and the oxidation rate increased with decreasing goethite particle size. The optimum oxidation rate was observed at the pH below 3.0.Addition of Fe2 +  and Fe3 +  can enhance the catalytic oxidation rate of 2-CP very efficiently. The main mechanism of goethite catalysing hydrogen peroxide to oxidise 2-CP may be due to the catalysis of ferrous ions and goethite surface.
Catalytic wet peroxidation of phenol in a fixed bed reactor
Authors: Martínez F. , Pariente M.I. , Melero J.A. , Botas J.A. , Gómez E.
Published: June 2007

Iron-containing mesostructured materials (Fe-SBA-15) are suitable for continuous treatment of phenolic aqueous solutions by means of catalytic wet peroxide oxidation (CWPO) in a packed-bed reactor. These materials were successfully extruded, crushed and sieved with a particle size ranging from 1 to 1.6 mm using mineral clay and methyl cellulose as binders. Non-significant changes have been found in the textural and structural properties of the extruded material in comparison to the parent powder Fe-SBA-15 material. Activity of extruded catalyst in terms of phenol degradation and TOC reduction has been monitored in a continuous mode. The increase of residence time enhances significantly the TOC degradation. The catalyst stability, taking into account the loss of iron species from the catalyst into the aqueous solution, has also been examined. The catalytic results of Fe-SBA-15 material in comparison to a homogeneous catalytic test prove the relevant role of the solid catalyst in the oxidation process.
A modified advanced Fenton process for industrial wastewater treatment
Authors: Chakinala A.G. , Bremner D.H. , Burgess A.E. , Namkung K.C.
Published: June 2007

For the first time hydrodynamic cavitation induced by a liquid whistle reactor (LWR) has been used in conjunction with the advanced Fenton process (AFP) for the treatment of industrial wastewater. Semi-batch experiments in the LWR were designed to investigate the performance of the process by optimising various parameters such as pressure, pH, H2O2 concentration and the concentration of industrial wastewater samples on the mineralisation of the total organic carbon (TOC). It was found that higher pressures are more favourable for a rapid TOC mineralisation.
Degradation of polyethylene glycol by Fenton reaction: a comparative study
Authors: Haseneder R. , Fdez-Navamuel B. , Härtel G.
Published: June 2007

Photochemical advanced oxidation processes (AOPs) utilising different Fenton systems were investigated in laboratory-scale experiments for the degradation of polyethylene glycol (PEG). The results of the study showed that the degradation rate of PEG was strongly accelerated by the homogeneous system, and this proved to be advantageous in comparison to the heterogeneous system. Between Fenton and photo-Fenton heterogeneous systems, the photo-Fenton process reached the highest removal rate of the organic compound, due to the enhanced reduction efficiency of Fe(III) to Fe(II) under UV-irradiation. The oxidation rate in the heterogeneous system was investigated using varying different parameters, such as the pH value, the concentration of hydrogen peroxide and the amount of Fe(OH)3 as the catalyst. For the homogeneous Fenton system the rate of degradation is significantly higher. At the same time of operation the elimination rates can be found to be 30% over the rates of the heterogeneous system. Optimising the typical influence parameters mentioned before, a degradation of about 93% of PEG can be achieved by using the homogeneous Fenton system.
Approach to TiO2–light interaction in heterogeneous photocatalysis
Authors: Bayarri B. , Illana E. , Curcó D. , Giménez J. , Esplugas S.
Published: June 2007

Photocatalysis can be a useful tool in the treatment of some recalcitrant and toxic pollutants. In fact, it is being applied today in several industrial processes. However some problems arise in the modelling of photocatalytic systems, most of them related to the radiation field. In this work, some methods are presented which can be powerful tools in the evaluation of the radiation absorbed by the photocatalyst, which is the energy really useful in promoting the photocatalytic process. All these methods are based on actinometric procedures carried out in different experimental conditions and using different photoreactors.
The adsorption and photodegradation of oxalic acid at the TiO2 surface
Authors: Mendive Cecilia B. , Blesa Miguel A. , Bahnemann Detlef
Published: June 2007

ATR–FTIR measurements in combination with quantum chemical calculations were performed to study chemical reactions taking place at the surface of a thin TiO2 layer immersed in an aqueous oxalic acid solution under UV(A) illumination. It was found that the adsorption of oxalic acid on TiO2 in the dark can be explained in terms of two surface complexes for the anatase phase. Under UV(A) illumination, one of the adsorbed species on the anatase phase preferably undergoes photo-degradation and at the same time more molecules of oxalic acid are adsorbed at the TiO2 surface which is thus enriched in the second complexation mode. The spectral changes observed under UV(A) illumination are explained in the light of different theories: photo-desorption of water molecules as a thermal mechanism induced by the absorption of photons, surface reconstruction, and newly exposed surface area provided by the de-aggregation of the TiO2 particles.
The use of catalyst to enhance the wet oxidation process
Authors: Maugans C. , Kumfer B.
Published: June 2007

Wet oxidation tests were performed on two pure compound streams: acetic acid and ammonia; and on two wastewater streams: acrylic acid wastewater and sulphide laden spent caustic. Test results showed that Mn/Ce and Pt/TiO2 were effective catalysts that greatly enhanced acetic acid, ammonia and acrylic acid wastewater destruction. However, the Mn/Ce catalyst performance appears to be inhibited by concentrated salts dissolved in solution. This could limit the applicability of this catalyst for the treatment of brackish wastewaters. Zr, Ce and Ce nanoparticles were also shown to exhibit some catalytic activity, however not to the extent of the Mn/Ce and the Pt/TiO2.
Ultrasound as a pre-oxidation for biological landfill leachate treatment
Authors: Neczaj E. , Kacprzak M.
Published: June 2007

In this study, the effects of low energy ultrasound irradiation on landfill leachate treatment by means of sequencing bath reactor were investigated. The aim of this work was to estimate the influence of leachate irradiation time on aerobic treatment efficiency. The sonification of the leachate was carried out in static conditions using the disintegrator UD-20. The field frequency of 22 kHz (the power output equals to 180 W) and amplitude of 12 μm was applied. The sonification time was changed in the range of 30–140 s. It was found that ultrasonic pretreatment enhances the subsequent aerobic digestion resulting in a better degradation of landfill leachate. The sonification of raw leachate leads to enhancement of COD and ammonia removal as compare to experiment without ultrasound.
Potential of activated sludge ozonation
Authors: Boehler M. , Siegrist H.
Published: June 2007

The disposal of sewage sludge and the agricultural use of stabilised sludge are decreasing due to more stringent regulations in Europe. An increasing fraction of sewage sludge must therefore be dewatered, dried, incinerated and the ashes disposed of in landfills. These processes are cost-intensive and also lead to the loss of the valuable phosphate resources incorporated in the sludge ash. The implementation of processes that could reduce excess sludge production and recycle phosphate is therefore recommended. Partial ozonation of the return sludge of an activated sludge system significantly reduces excess sludge production, improves the settling properties of the sludge and reduces bulking and scumming. The solubilised COD will also improve denitrification if the treated sludge is recycled to the anoxic zone. However, ozonation partly kills nitrifiers and could therefore lead to a decrease of the effective solid retention time of the nitrifier, thus reducing the safety of the nitrification. This paper discusses the effect of ozonation on sludge reduction, the operating stability of nitrification, the improvement of denitrification and also presents an energy and cost evaluation.
Applications of AOPs in wastewater treatment
Authors: Vogelpohl A.
Published: June 2007

As Advanced Oxidation Processes (AOPs) are based on radical reactions that are very fast, non-selective and can completely oxidise substances, they have great potential for the removal of non-biodegradable pollutants from municipal and industrial wastewater. However, although there has been much progress in understanding AOPs, most work has been limited to laboratory or pilot-plant scale; there are few reports on industrial applications of AOP for wastewater treatment and hardly any disclose costs. Publication of such studies is needed if AOPs are to gain wide application as an alternative to more conventional treatment methods.
Recalcitrant COD degradation by an integrated system of ozonation and membrane bioreactor
Authors: Gommers K. , De Wever H. , Brauns E. , Peys K.
Published: June 2007

In order to treat wastewater to a low residual COD-concentration such as 125 mg/L, classical biological treatment is not sufficient for many types of industry. This research focused on the integrated treatment of the wastewater of the paper industry, with a membrane bioreactor (MBR) and an oxidation step. The optimal configuration was examined. Screening tests with different types of oxidation showed that ozonation after biological treatment could reduce the COD with 40% with an ozone dose of 0.4–0.8 g O3/g COD. BOD/COD ratio could be increased up to 0.19. Neither combination of ozone with UV and/or hydrogen peroxide nor the process H2O2/UV or (photo-)Fenton reagents gave any improvement in COD reduction or BOD increase, unless the doses were very high. Based on these results, an integrated system MBR–ozonation was designed, with recirculation of MBR effluent over ozonation. This test showed that reduction of COD up to 125 mg/L immediately behind the MBR required a lot of ozone. A technically feasible solution was to discharge the water after an extra ozonation step, which resulted in a high total ozone dosage. The alternative, the consecutive treatment activated sludge–ozonation–activated sludge, did not give a better COD-removal with the same ozone dose as the integrated concept. The economic evaluation proves that the integrated chemical and biological treatment is expensive for the paper industry if a low discharge limit of COD has to be complied with.
Phenol wastewater remediation: advanced oxidation processes coupled to a biological treatment
Authors: Rubalcaba A. , Suárez-Ojeda M.E. , Stüber F. , Fortuny A. , Bengoa C. , Metcalfe I. , Font J. , Carrera J. , Fabregat A.
Published: June 2007

Nowadays, there are increasingly stringent regulations requiring more and more treatment of industrial effluents to generate product waters which could be easily reused or disposed of to the environment without any harmful effects. Therefore, different advanced oxidation processes were investigated as suitable precursors for the biological treatment of industrial effluents containing phenol. Wet air oxidation and Fenton process were tested batch wise, while catalytic wet air oxidation and H2O2-promoted catalytic wet air oxidation processes were studied in a trickle bed reactor, the last two using over activated carbon as catalyst. Effluent characterisation was made by means of substrate conversion (using high liquid performance chromatography), chemical oxygen demand and total organic carbon. Biodegradation parameters (i.e. maximum oxygen uptake rate and oxygen consumption) were obtained from respirometric tests using activated sludge from an urban biological wastewater treatment plant (WWTP). The main goal was to find the proper conditions in terms of biodegradability enhancement, so that these phenolic effluents could be successfully treated in an urban biological WWTP. Results show promising research ways for the development of efficient coupled processes for the treatment of wastewater containing toxic or biologically non-degradable compounds.
An overview of the integration of ozone systems in biological treatment steps
Authors: Ried A. , Mielcke J. , Wieland A. , Schaefer S. , Sievers M.
Published: June 2007

Despite the well-known potential and performance of combined biological and ozonation processes for wastewater treatment, only few full-scale applications are published. Beside the synergistic effects of such process combination, which lead to oxidation of recalcitrant and inhibitory compounds or intermediates by enhancement of their biodegradability, the key for raising applicability is the improvement of the ozonation efficiency. An overview about the history and progress of full-scale applications, which deals with combined ozonation and biological treatment is given. Recently more than 40 applications exist, but many of them are not published. Therefore, a couple of selected not yet published applications have been mentioned in this paper. Landfill leachate and industrial wastewater treatment were mostly applicated, while treatment of municial wastewater treatment plant (WWTP) effluents are of increasing interest due to several advantages such as disinfection, decolourisation and removal of persistent dissolved organic carbon (DOC) for water re-use and groundwater recharge.
Ozone catalysed with solids as an advanced oxidation process for landfill leachate treatment
Authors: Tizaoui C. , Mansouri L. , Bousselmi L.
Published: June 2007

Heterogeneous catalytic ozonation (HCO) of wastewater is gaining both research and industrial interests. It is proved to be an advanced oxidation process since it involves hydroxyl radicals as oxidation species. Few studies have been carried out to test HCO in the treatment of landfill leachates. This work has been carried out to test three types of catalysts: activated carbon (AC), expanded perlite (EP) and titanium dioxide (TiO2) combined with ozone at 80 g/m3 gas concentration for the treatment of a leachate generated by Jebel Chakir landfill site near Tunis–capital of Tunisia. The work has shown a reduction in COD of about 45% and an increase in biodegradability (BOD5/COD) from 0.1 to 0.34. A catalyst concentration of 0.7 g/L was found optimal for the treatment of the leachate.
Pilot-plant results of the electro-Fenton treatment of olive mill wastewaters followed by anaerobic digestion
Authors: Khoufi S. , Feki F. , Aloui F. , Sayadi S.
Published: June 2007

In this work, we investigated an integrated technology for the treatment of the recalcitrant contaminants of olive mill wastewaters (OMW), allowing water recovery and reuse for agricultural purposes. The method involves an electrochemical pre-treatment step of the wastewater using the electro-Fenton reaction followed by an anaerobic bio-treatment. The electro-Fenton pre-treatment process removed 66% of the total polyphenolic compounds and subsequently decreased the OMW toxicity from 100 to 66.9% which resulted in improving the performance of the anaerobic digestion. A continuous lab-scale methanogenic reactor was operated at a loading rate of 10 g COD/L day without any apparent toxicity. Furthermore, in the combined process, a high overall reduction in COD, suspended solids, polyphenols and lipids content was achieved by the two successive stages. Moreover, this combined process which was experimented at a real scale (25 m3 digester), demonstrated its technical feasibility and opens promising perspectives for industrial application in the Mediterranean countries due to its easy conception and its high energy (methane) production.
SUVA as control parameter for the effective ozonation of organic pollutants in secondary effluent
Authors: Bahr C. , Schumacher J. , Ernst M. , Luck F. , Heinzmann B. , Jekel M.
Published: June 2007

Recent research projects have shown a good suitability of the ozonation process to transform trace concentrations of most pharmaceuticals in wastewater treatment plant (WWTP) effluents. The concentrations of carbamazepine and 17α-ethinylestradiol, for instance, were reduced below their detection limits by use of ozone dosages resulting in a specific ozone consumption of 0.5 mg O3/mg DOC0. At the same time a good disinfection performance was achieved. The given hygienic requirements of the EU bathing water directive (e.g. 2,000 N/100 mL faecal coliforms) are fulfilled without the formation of bromate (<10 μg/L). As technical control parameter of the ozonation process usually the residual ozone in the liquid phase or in the off-gas are used. However, at very low specific ozone consumptions, ozone reacts instantaneously with dissolved compounds and cannot be detected. Hence, alternative parameters should be used for effective operation control. The present paper evaluates the relation between UVA decrease and the removal of different compounds (endocrine disrupting compounds, pharmaceuticals, iodinated X-ray contrast media), microbial parameters and bromate formation. The results can be used as a guideline for the control of the oxidation performance at large scale ozonation units.
The occurrence of micopollutants in the aquatic environment: a new challenge for water management
Authors: Ternes T.
Published: June 2007

The occurrence of micropollutants in the aquatic environment has become a crucial topic in the last two decades owing to the innovative development of analytical instrumentation such as LC tandem MS. Using these new techniques it became obvious that pesticides, pharmaceuticals, ingredients of personal care products, biocides, flame retardants, and perfluorinated compounds are entering rivers and streams via treated wastewater. Also contamination of bank filtrates, groundwater and in a few cases even drinking water was identified. Wastewater treatment plants are not designed to remove polar persistent organic pollutants occurring in the sub-mg/L range and hence many of these organic pollutants are passing WWTPs to a high extent. Waterworks with a potential pesticide contamination in their raw water are equipped with advanced techniques such ozonation, activated carbon or nanofiltration enabling the removal of a high variety of other organic compounds. However, waterworks without an expected pesticide contamination are frequently equipped with common treatment processes not enabling the removal of these kinds of organic pollutants. Therefore, comprehensive management activities for protection of aquatic environments and water resources must consider the removal of all micropollutants relevant to water quality and ecology, independent of their usage or origin.
Effects of Video Streaming Technology on Public Speaking Students' Communication Apprehension and Competence
Authors: Dupagne Michel , Stacks Don W. , Giroux Valerie Manno
Published: June 2007

This study examines whether video streaming can reduce trait and state communication apprehension, as well as improve communication competence, in public speaking classes. Video streaming technology has been touted as the next generation of video feedback for public speaking students because it is not limited by time or space and allows Internet users to view video content without prior downloading. Seventy-two public speaking students in two treatment classes and two control classes taught by the same instructor participated in a quasi-experiment to test three hypotheses. Although students who had viewed their speeches online reacted positively to their video streaming experience, results revealed no significant differences in communication apprehension and competence between the treatment and control groups.
The Effects of Personality Type on Web-Based Distance Learning
Authors: Bishop-Clark Cathy , Dietz-Uhler Beth , Fisher Amy
Published: June 2007

Web-based distance learning is a relatively new approach in higher education which is gaining in popularity. Because a Web-based classroom is so different than a traditional face-to-face classroom, the variables that influence success or satisfaction with such a course may be different than those in a face-to-face course. We investigated whether student performance and satisfaction in an asynchronous, Web-based distance learning course differed based on personality factors (as measured by the Myers Briggs Type Indicator). Twenty-nine students taking an introductory psychology course participated in the study. Results indicate that personality preference has little relationship with student performance, but several dimensions of personality did influence satisfaction.
Instructor Based Training versus Computer Based Training—A Comparative Study
Authors: Malmsköld Lennart , Örtengren Roland , Carlson Blair E. , Nylen Per
Published: June 2007

This article describes two studies conducted to compare assembly performance and learning rate between computer based training and traditional training of skilled assembly operators. The studies were performed with pre-series production parts from a car cockpit and they were integrated as part of the overall training activities during a new vehicle product launch. The computer based training tool used was a desktop based commercial VR tool with focus on cognitive interactive procedural learning. Both studies indicate that computer based training can replace instructor based training for this level of assembly complexity and that it has a positive effect in preparing skilled operators.
The Development of a Virtual Dinosaur Museum
Authors: Tarng Wernhuar , Liou Hsin-Hun
Published: June 2007

The objective of this article is to study the network and virtual reality technologies for developing a virtual dinosaur museum, which provides a Web-learning environment for students of all ages and the general public to know more about dinosaurs. We first investigate the method for building the 3D dynamic models of dinosaurs, and then describe the process of designing the virtual scenes as well as the functions provided by the Website, including exhibition of dinosaurs and fossils, breeding dinosaur, treasure hunting, network resources, and discussion area. The virtual dinosaur museum provides 3D visual effect and interactive interface, and thus can be used as a teaching aid in the field of natural science and life technologies. It can be used as an alternative and interesting way to enhance the knowledge about dinosaurs. We have conducted an experiment at primary schools by questionnaires and observing students' reactions after browsing the Website. The results can be used as reference for improving the system in the future.
Untersuchungen zum Einfluss der Holzfeuchtigkeit auf das Bruchverhalten von Fichte bei Zugbelastung in Faserrichtung | The influence of moisture content on the fracture behaviour of Norway spruce when tension is applied in the direction of the grain
Authors: Szalai Jozsef , Niemz Peter , Andor Krisztian , Bariska Mihaly , Howald Martin T.
Published: June 2007

The influence of wood moisture content on the fracture behaviour of Norway spruce was investigated. The tensile strength rose to around 10% in samples with a lower moisture content. After reaching the maximum below the level of fibre saturation, it falls back, almost linearly. Irrespective of the moisture content, a rigid fracture behaviour was observed.
Über Perspektiven zukunftsorientierter Waldwirtschaft - Betriebspolitisches Handeln in gesellschaftlichen Spannungsfeldern | The perspectives for future-oriented forestry management - managerial decisions under social tension
Authors: Oesten Gerhard
Published: June 2007

Forest management in central Europe is in the grip of radical change, which has taken on the character of a crisis. The main reasons for this crisis are a fall in profit and the many social altercations over the use of forest resources. The results of the crisis are manifest in the conflict-laden negotiations on the new formulation of the institutions in the forest sector in society,but also in a polymorphic identity crisis of foresters and managers and their sometimes frustrating search for ways and possibilities of running an enterprise faced with the tensions within society at large. In this paper we introduce a management concept (based on the St. Gallen management method),we diagnose the shortcomings of strategic and especially normative management of forest enterprises, and we advocate a professional management policy.
Bestandesdynamik zentralalpiner Waldföhrenwälder aufgezeigt anhand dendroökologischer Fallstudien aus dem Wallis, Schweiz | Stand dynamics of central alpine Scots pine using dendroecological case studies from Valais, Switzerland
Authors: Rigling Andreas , Weber Pascale , Cherubini Paolo , Dobbertin Matthias
Published: June 2007

The aim of this paper is to demonstrate the use of dendroecological methods to analyse the various processes involved in forest dynamics. Using dendroecological case studies of the Scots pine forests of Valais (Switzerland) as an example we discuss the most relevant processes of forest dynamics and their consequences on stand structures and mortality rates. We focus on the development history of these Scots pine forests under human impact and on the impact of biotic and abiotic factors on tree growth.

Most of today's extended Scots pine forests (< 1500 m a.s.l.)must be interpreted as part of an ongoing natural succession under heavy human influence. In time, without management or natural disturbances, most of these pine forests will develop into broadleaved forests (lower altitudes) or spruce-firforests(higher altitudes).
Jahrringe und Landschaftsentwicklung auf der Alpensüdseite | Tree-rings and landscape development on the southern side of the Alps
Authors: Conedera Marco , Fonti Patrick , Krebs Patrik , Rigling Andreas
Published: June 2007

Tree-ring analysis is one of the most suitable methods for studying processes in landscape dynamics. In southern Switzerland these dynamics are extremely varied and rapid, which makes the use of dendrochronological and dendroecological methods particularly interesting. In 2003 the Sottostazione Sud delle Alpi of the WSL decided to enlarge its field of activities, making dendrochronology one of their core method of research. First studies are underway and possible applications are presented as case studies in this contribution.
Geomorphologie und Jahrringe – Feldmethoden in der Dendrogeomorphologie | Geomorphology and tree rings – field methods in dendrogeomorphology
Authors: Gärtner Holger , Esper Jan , Treydte Kerstin
Published: June 2007

In terms of the spatiotemporal reconstruction of geomorphic processes the application of tree-ring analysis has the highest level of temporal resolution in geomorphology. Dating and the resulting reconstructions can be assigned to exact calendar years, sometimes even to specific seasons. To guarantee this,one has to take into account that there are great differences between methods in the field and other tree-ring related fields of research. Following site selection a detailed relief analysis and process must be carried out in order to determine and select those trees obviously disturbed by these processes. The method of sampling is of the utmost importance. Selection of the samples must be based on the estimated kind of disturbance and therefore corresponds to the specific disturbance of a given species and not to the site being investigated. Furthermore,in order to be able to accurately date the disturbances it is absolutely essential to produce a local reference chronology.