Characterization of water-soluble organic compounds in ambient aerosol using ultrahigh-resolution elctrospray ionization fourier transform ion cyclotron resonance mass spectrometry.

Atmospheric aerosol water-soluble organic compounds (WSOC) exist in a complex mixture of thousands of organic compounds which may have a significant influence on the climate-relevant properties of the atmospheric aerosol. To understand the potential influences, the ambient aerosol was collected at a nonurban mountainous site near Steamboat Springs, CO. The WSOC fraction was analyzed using positive and negative electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry. Approximately 2400 and 4000 molecular formulas were identified from the detected positive and negative ions, respectively. The formulas contained carbon (C), hydrogen (H), oxygen (O), nitrogen (N), and sulfur (S) atoms over the mass range of 100-800 Da in both ionization modes. The number range of double bond equivalents (DBE), the mean O:C, H:C, and oxidation state of carbon for the positive ions were 0 – 18, 0.25 ± 0.15, 1.39 ± 0.29, and -0.89 ± 0.23, respectively. Comparatively, the negative ion values were 0 – 14, 0.53 ± 0.20, 1.48 ± 0.30, and -0.41 ± 0.45, respectively. Overall, the positive ion molecular formulas were less oxygenated than negative ions as seen with the lower O:C and OSc values. Molecular formulas of the positive ions classified as aliphatic, olefinic, and aromatic compound classes based on the aromaticity index values. Aliphatic compounds were the CHNO and CHO formulas that had mean DBE values of about 5 and 3, respectively. However, a majority of the CHOS, CHNOS, and CHS formulas were defined as olefinic compounds and had mean DBE values of about 12, 13, and 10, respectively. Overall, more than half of the assigned molecular formulas contained sulfur and were olefinic to aromatic compounds with a DBE range of 7-18. Source of the unsaturated sulfur containing compounds is currently unknown. Several nitrogen containing compounds were in common with the field and laboratory studies of the biomass burning aerosol and aged secondary organic aerosol products of the limonene ozonolysis.

DYNAMICS AND CONTROL OF REACTIVE DISTILLATION PROCESS FOR MONOMER SYNTHESIS OF POLYCARBONATE PLANTS

Polycarbonate (PC) is an important engineering thermoplastic that is currently produced in large industrial scale using bisphenol A and monomers such as phosgene. Since phosgene is highly toxic, a non-phosgene approach using diphenyl carbonate (DPC) as an alternative monomer, as developed by Asahi Corporation of Japan, is a significantly more environmentally friendly alternative. Other advantages include the use of CO2 instead of CO as raw material and the elimination of major waste water production. However, for the production of DPC to be economically viable, reactive-distillation units are needed to obtain the necessary yields by shifting the reaction-equilibrium to the desired products and separating the products at the point where the equilibrium reaction occurs. In the field of chemical reaction engineering, there are many reactions that are suffering from the low equilibrium constant. The main goal of this research is to determine the optimal process needed to shift the reactions by using appropriate control strategies of the reactive distillation system. An extensive dynamic mathematical model has been developed to help us investigate different control and processing strategies of the reactive distillation units to increase the production of DPC. The high-fidelity dynamic models include extensive thermodynamic and reaction-kinetics models while incorporating the necessary mass and energy balance of the various stages of the reactive distillation units. The study presented in this document shows the possibility of producing DPC via one reactive distillation instead of the conventional two-column, with a production rate of 16.75 tons/h corresponding to start reactants materials of 74.69 tons/h of Phenol and 35.75 tons/h of Dimethyl Carbonate. This represents a threefold increase over the projected production rate given in the literature based on a two-column configuration. In addition, the purity of the DPC produced could reach levels as high as 99.5% with the effective use of controls. These studies are based on simulation done using high-fidelity dynamic models.

COORDINATION CHEMISTRY OF BIS(BENZYL)PHOSPHINATE

The work presented in this dissertation deals with the coordination chemistry of the bis(benzyl)phosphinate ligand with vanadium, tungsten and cobalt. The long term goal of this project was to produce and physically characterize high oxidation state transition metal oxide phosphinate compounds with potential catalytic applications. The reaction of bis(benzyl)phosphinic acid with VO(acac)2 in the presence of water or pyridine leads to the synthesis of trimeric vanadium(IV) clusters (V3(µ3-O)O2)(µ2-O2P(CH2C6H5)2)6(H2O) and (V3(µ3-O)O2)(µ2-O2P(CH2C6H5)2)6(py). In contrast, when diphenylphosphinic acid or 2-hydroxyisophosphindoline-2-oxide were reacted with VO(acac)2, insoluble polymeric compounds were produced. The trimeric clusters were characterized using FTIR, elemental analysis, single crystal diffraction, room temperature magnetic susceptibility, thermogravimetric analysis and differential scanning calorimetry. The variable-temperature, solid-state magnetic susceptibility was measured on (V3(µ3-O)O2)(µ2-O2P(CH2C6H5)2)6(py). The polymeric compounds were characterized using FTIR, powder diffraction and elemental analysis. Two different cubane clusters made of tungsten(V) and vanadium(V) were stabilized using bis(benzyl)phosphinate. The oxidation of (V3(µ3-O)O2)(µ2-O2P(CH2C6H5)2)6(H2O) with tBuOOH led to the formation of V4(µ3-O)4(µ2-O2P(Bn)2)4(O4). W4(µ3-O)4(µ2-O2P(Bn)2)4(O4) was produced by heating W(CO)6 in a 1:1 mixture of EtOH/THF at 120 ˚C. Both compounds were characterized using single crystal diffraction, FTIR, 31P-NMR, 1H-NMR and elemental analysis. W4(µ3-O)4(µ2-O2P(Bn)2)4(O4) was also characterized using UV-vis. Cobalt(II) reacted with bis(benzyl)phosphinate to produce three different dinuclear complexes. [(py)3Co(µ2-O2P(Bn)2)3Co(py)][ClO4], (py)3Co(µ2-O2P(Bn)2)3Co(Cl) and (py)(µ2-NO3)Co(µ2-O2P(Bn)2)3Co(py) were all characterized using single crystal diffraction, elemental analysis and FTIR. Room temperature magnetic susceptibility measurements were performed on [(py)3Co(µ2-O2P(Bn)2)3Co(py)][ClO4] and (py)3Co(µ2-O2P(Bn)2)3Co(Cl). The variable-temperature, solid-state magnetic susceptibility was also measured on [(py)3Co(µ2-O2P(Bn)2)3Co(py)][ClO4].

REMEDIATION OF TETRACYCLINE FROM WATER SOURCES USING VETIVER GRASS (Chrysopogon zizanioides L. Nash) AND TETRACYCLINE-TOLERANT ROOT-ASSOCIATED BACTERIA

Antibiotics are emerging contaminants worldwide. Due to insufficient policy regulations, public awareness, and the constant exposure of the environment to antibiotic sources has created a major environmental concern. Wastewater treatment plants (WWTP) are not equipped to filter-out these compounds before the discharge of the disinfected effluent into water sources (e.g., lakes and streams) and current available technologies are not equipped to remediate these compounds from environmental sources. Hence, the challenge remains to establish a biological system to remove these antibiotics from wastewater. An invitro hydroponic remediation system was developed using vetiver grass (Chrysopogon zizanioides L. Nash) to remediate tetracycline (TC) from water. Comparative metabolomics studies were conducted to investigate the metabolites/pathways associated with tetracycline metabolism in plants and TC-degrading bacteria. The results show that vetiver plants effectively uptake tetracycline from water sources. Vetiver root-associated bacteria recovered during the hydroponic remediation trial were highly tolerant to TC (as high as 600 ppm) and could use TC as a sole carbon and energy source. Growth conditions (pH, temperature, and oxygen requirement) for TC-tolerant bacteria were optimized for higher TC remediation capability from water sources. The plant (roots and shoots) and bacterial species were further characterized for the metabolites produced during the TC degradation process using GC-MS to identify the possible biochemical mechanism involved. Also, the plant root zone was screened for metabolites/enzymes that were secreted during antibiotic degradation and could potentially enhance the degradation process. The root zone was selected for this analysis because this region of the plant has shown a greater capacity for antibiotic degradation compared to the shoot zone. The role of antioxidant enzymes in TC degradation process revealed glutathione-S-transferase (GSTs) as an important group of enzymes in both plant and bacteria potentially involved in TC degradation process. Metabolomics results also suggest potential GST activity in the TC remediation/ transformation process used by plants. This information could be useful in gaining insights for the application of biological remediation systems for the mitigation of antibiotics from waste-water.

The effect of demand, tank parameters, and pumping stations on energy use in municipal drinking water distribution systems

Two of the indicators of the UN Millennium Development Goals ensuring environmental sustainability are energy use and per capita carbon dioxide emissions. The increasing urbanization and increasing world population may require increased energy use in order to transport enough safe drinking water to communities. In addition, the increase in water use would result in increased energy consumption, thereby resulting in increased green-house gas emissions that promote global climate change. The study of multiple Municipal Drinking Water Distribution Systems (MDWDSs) that relates various MDWDS aspects--system components and properties--to energy use is strongly desirable. The understanding of the relationship between system aspects and energy use aids in energy-efficient design. In this study, components of a MDWDS, and/or the characteristics associated with the component are termed as MDWDS aspects (hereafter--system aspects). There are many aspects of MDWDSs that affect the energy usage. Three system aspects (1) system-wide water demand, (2) storage tank parameters, and (3) pumping stations were analyzed in this study. The study involved seven MDWDSs to understand the relationship between the above-mentioned system aspects in relation with energy use. A MDWDSs model, EPANET 2.0, was utilized to analyze the seven systems. Six of the systems were real and one was a hypothetical system. The study presented here is unique in its statistical approach using seven municipal water distribution systems. The first system aspect studied was system-wide water demand. The analysis involved analyzing seven systems for the variation of water demand and its impact on energy use. To quantify the effects of water use reduction on energy use in a municipal water distribution system, the seven systems were modeled and the energy usage quantified for various amounts of water conservation. It was found that the effect of water conservation on energy use was linear for all seven systems and that all the average values of all the systems' energy use plotted on the same line with a high R 2 value. From this relationship, it can be ascertained that a 20% reduction in water demand results in approximately a 13% savings in energy use for all seven systems analyzed. This figure might hold true for many similar systems that are dominated by pumping and not gravity driven. The second system aspect analyzed was storage tank(s) parameters. Various tank parameters: (1) tank maximum water levels, (2) tank elevation, and (3) tank diameter were considered in this part of the study. MDWDSs use a significant amount of electrical energy for the pumping of water from low elevations (usually a source) to higher ones (usually storage tanks). The use of electrical energy has an effect on pollution emissions and, therefore, potential global climate change as well. Various values of these tank parameters were modeled on seven MDWDSs of various sizes using a network solver and the energy usage recorded. It was found that when averaged over all seven analyzed systems (1) the reduction of maximum tank water level by 50% results in a 2% energy reduction, (2) energy use for a change in tank elevation is system specific, and (2) a reduction of tank diameter of 50% results in approximately a 7% energy savings. The third system aspect analyzed in this study was pumping station parameters. A pumping station consists of one or more pumps. The seven systems were analyzed to understand the effect of the variation of pump horsepower and the number of booster stations on energy use. It was found that adding booster stations could save energy depending upon the system characteristics. For systems with flat topography, a single main pumping station was found to use less energy. In systems with a higher-elevation neighborhood, however, one or more booster pumps with a reduced main pumping station capacity used less energy. The energy savings for the seven systems was dependent on the number of boosters and ranged from 5% to 66% for the analyzed five systems with higher elevation neighborhoods (S3, S4, S5, S6, and S7). No energy savings was realized for the remaining two flat topography systems, S1, and S2. The present study analyzed and established the relationship between various system aspects and energy use in seven MDWDSs. This aids in estimating the amount of energy savings in MDWDSs. This energy savings would ultimately help reduce Greenhouse gases (GHGs) emissions including per capita CO 2 emissions thereby potentially lowering the global climate change effect. This will in turn contribute to meeting the MDG of ensuring environmental sustainability.

WATER ACCESS AND MAINTENANCE IN KARONGA, MALAWI

This report is a case study of how Mwangalala community accesses water and how that access is maintained. Mwangalala community is located in the northern tip of Karonga district in Malawi, Africa. The case study evaluates how close the community is to meeting target 10 of the Millennium Development Goals, sustainable access to safe drinking water, and evaluates the current water system through Human Centered Design’s criteria of desirability, feasibility, and viability. It also makes recommendations to improve water security in Mwangalala community. Data was collected through two years of immersive observation, interviews with 30 families, and observing two wells on three separate occasions. The 30 interviews provided a sample size of over 10% of the community’s population. Participants were initially self-selected and then invited to participate in the research. I walked along community pathways and accepted invitations to join casual conversations in family compounds. After conversing I asked the family members if they would be willing to participate in my research by talking with me about water. Data collected from the interviews and the observations of two wells were compared and analyzed for common themes. Shallow wells or open wells represented the primary water source for 93% of interview participants. Boreholes were also present in the community, but produced unpalatable water due to high concentrations of dissolved iron and were not used as primary water sources. During observations 75% of community members who used the shallow well, primarily used for consumptive uses like cooking or dinking, were females. Boreholes were primarily used for non-consumptive uses such as watering crops or bathing and 77% of the users were male. Shallow wells could remain in disrepair for two months because the repairman was a volunteer, who was not compensated for the skilled labor required to repair the wells. Community members thought the maintenance fee went towards his salary, so did not compensate the repairman when he performed work. This miscommunication provided no incentive for the repairman to make well repairs a priority, and left community members frustrated with untimely repairs. Shallow wells with functional pumps failed to provide water when the water table levels drop during dry season, forcing community members to seek secondary or tertiary water sources. Open wells, converted from shallow wells after community members did not pay for repairs to the pump, represented 44% of the wells originally installed with Mark V hand pumps. These wells whose pumps were not repaired were located in fields and one beside a church. The functional wells were all located on school grounds or in family compounds, where responsibility for the well’s maintenance is clearly defined. Mwangalala community fails to meet Millennium Development goals because the wells used by the community do not provide sustainable access to safe drinking water. Open wells, used by half the participants in the study, lack a top covering to prevent contamination from debris and wildlife. Shallow well repair times are unsustainable, taking longer than two weeks to be repaired, primarily because the repair persons are expected to provide skilled labor to repair the wells without compensation. Improving water security for Mwangalala can be achieved by improving repair times on shallow wells and making water from boreholes palatable. There are no incentives for a volunteer repair person to fix wells in a timely manner. Repair times can be improved by reducing the number of wells a repair person is responsible for and compensating the person for the skilled labor provided. Water security would be further improved by removing iron particulates from borehole water, thus rendering it palatable. This is possible through point of use filtration utilizing ceramic candles; this would make pumped water available year-round.

Electrospun Quaternized Chitosan Fibers for Virus Removal from Drinking Water

Membrane filtration has become an accepted technology for the removal of pathogens from drinking water. Viruses, known to contaminate water supplies, are too small to be removed by a size-exclusion mechanism without a large energy penalty. Thus, functionalized electrospun membranes that can adsorb viruses have drawn our interest. We chose a quaternized chitosan derivative (HTCC) which carries a positively-charged quaternary amine, known to bind negatively-charged virus particles, as a functionalized membrane material. The technique of electrospinning was utilized to produce nanofiber mats with large pore diameters to increase water flux and decrease membrane fouling. In this study, stable, functionalized, electrospun HTCC-PVA nanofibers that can remove 3.6 logs (99.97%) of a model virus, porcine parvovirus (PPV), from water by adsorption and filtration have been successfully produced. This technology has the potential to purify drinking water in undeveloped countries and reduce the number of deaths due to lack of sanitation.

Diffusion of HTO, Br-, I-, Cs+, Sr-85(2+) and Co-60(2+) in a clay formation: Results and modelling from an in situ experiment in Opalinus Clay

The migration of radioactive and chemical contaminants in clay materials and argillaceous host rocks is characterised by diffusion and retention processes. Valuable information on such processes can be gained by combining diffusion studies at laboratory scale with field migration tests. In this work, the outcome of a multi-tracer in situ migration test performed in the Opalinus Clay formation in the Mont Terri underground rock laboratory (Switzerland) is presented. Thus, 1.16 x 10(5) Bq/L of HTO, 3.96 x 10(3) Bq/L of Sr-85, 6.29 x 10(2) Bq/L of Co-60, 2.01 x 10(-3) mol/L Cs, 9.10 x 10(-4) mol/L I and 1.04 x 10(-3) mol/L Br were injected into the borehole. The decrease of the radioisotope concentrations in the borehole was monitored using in situ gamma-spectrometry. The other tracers were analyzed with state-of-the-art laboratory procedures after sampling of small water aliquots from the reservoir. The diffusion experiment was carried out over a period of one year after which the interval section was overcored and analyzed. Based on the experimental data from the tracer evolution in the borehole and the tracer profiles in the rock, the diffusion of tracers was modelled with the numerical code CRUNCH. The results obtained for HTO (H-3), I- and Br- confirm previous lab and in situ diffusion data. Anionic fluxes into the formation were smaller compared to HTO because of anion exclusion effects. The migration of the cations Sr-85(2+), Cs+ and Co-60(2+) was found to be governed by both diffusion and sorption processes. For Sr-85(2+), the slightly higher diffusivity relative to HTO and the low sorption value are consistent with laboratory diffusion measurements on small-scale samples. In the case of Cs+, the numerically deduced high diffusivity and the Freundlich-type sorption behaviour is also supported by ongoing laboratory data. For Co, no laboratory diffusion data were yet available for comparison; however, the modelled data suggests that Co-60(2+) sorption was weaker than would be expected from available batch sorption data. Overall, the results demonstrate the feasibility of the experimental setup for obtaining high-quality diffusion data for conservative and sorbing tracers. (C) 2007 Elsevier Ltd. All rights reserved.

Central European hardwood trees in a high-CO 2 future: synthesis of an 8-year forest canopy CO 2 enrichment project

Rapidly increasing atmospheric CO2 is not only changing the climate system but may also affect the biosphere directly through stimulation of plant growth and ecosystem carbon and nutrient cycling. Although forest ecosystems play a critical role in the global carbon cycle, experimental information on forest responses to rising CO2 is scarce, due to the sheer size of trees. Here, we present a synthesis of the only study world-wide where a diverse set of mature broadleaved trees growing in a natural forest has been exposed to future atmospheric CO2 levels (c. 550ppm) by free-air CO2 enrichment (FACE). We show that litter production, leaf traits and radial growth across the studied hardwood species remained unaffected by elevated CO2 over 8years. CO2 enrichment reduced tree water consumption resulting in detectable soil moisture savings. Soil air CO2 and dissolved inorganic carbon both increased suggesting enhanced below-ground activity. Carbon release to the rhizosphere and/or higher soil moisture primed nitrification and nitrate leaching under elevated CO2; however, the export of dissolved organic carbon remained unaltered.Synthesis. Our findings provide no evidence for carbon-limitation in five central European hardwood trees at current ambient CO2 concentrations. The results of this long-term study challenge the idea of a universal CO2 fertilization effect on forests, as commonly assumed in climate-carbon cycle models.

Envisioning sustainable water futures in a transdisciplinary learning process: combining normative, explorative, and participatory scenario approaches

Competing water demands for household consumption as well as the production of food, energy, and other uses pose challenges for water supply and sustainable development in many parts of the world. Designing creative strategies and learning processes for sustainable water governance is thus of prime importance. While this need is uncontested, suitable approaches still have to be found. In this article we present and evaluate a conceptual approach to scenario building aimed at transdisciplinary learning for sustainable water governance. The approach combines normative, explorative, and participatory scenario elements. This combination allows for adequate consideration of stakeholders’ and scientists’ systems, target, and transformation knowledge. Application of the approach in the MontanAqua project in the Swiss Alps confirmed its high potential for co-producing new knowledge and establishing a meaningful and deliberative dialogue between all actors involved. The iterative and combined approach ensured that stakeholders’ knowledge was adequately captured, fed into scientific analysis, and brought back to stakeholders in several cycles, thereby facilitating learning and co-production of new knowledge relevant for both stakeholders and scientists. However, the approach also revealed a number of constraints, including the enormous flexibility required of stakeholders and scientists in order for them to truly engage in the co-production of new knowledge. Overall, the study showed that shifts from strategic to communicative action are possible in an environment of mutual trust. This ultimately depends on creating conditions of interaction that place scientists’ and stakeholders’ knowledge on an equal footing.

A COMPARISON OF TWO METHODS FOR THE DETECTION OF FECAL POLLUTION IN DRINKING WATER (HYDROGEN SULFIDE, INDICATOR, MODIFICATION)

A new technique for the detection of microbiological fecal pollution in drinking and in raw surface water has been modified and tested against the standard multiple-tube fermentation technique (most-probable-number, MPN). The performance of the new test in detecting fecal pollution in drinking water has been tested at different incubation temperatures. The basis for the new test was the detection of hydrogen sulfide produced by the hydrogen sulfide producing bacteria which are usually associated with the coliform group. The positive results are indicated by the appearance of a brown to black color in the contents of the fermentation tube within 18 to 24 hours of incubation at 35 (+OR-) .5(DEGREES)C. For this study 158 water samples of different sources have been used. The results were analyzed statistically with the paired t-test and the one-way analysis of variance. No statistically significant difference was noticed between the two methods, when tested 35 (+OR-) .5(DEGREES)C, in detecting fecal pollution in drinking water. The new test showed more positive results with raw surface water, which could be due to the presence of hydrogen sulfide producing bacteria of non-fecal origin like Desulfovibrio and Desulfomaculum. The survival of the hydrogen sulfide producing bacteria and the coliforms was also tested over a 7-day period, and the results showed no significant difference. The two methods showed no significant difference when used to detect fecal pollution at a very low coliform density. The results showed that the new test is mostly effective, in detecting fecal pollution in drinking water, when used at 35 (+OR-) .5(DEGREES)C. The new test is effective, simple, and less expensive when used to detect fecal pollution in drinking water and raw surface water at 35 (+OR-) .5(DEGREES)C. The method can be used for qualitative and/or quantitative analysis of water in the field and in the laboratory. ^

Influence of Equatorial Diatom Processes on Si Deposition and Atmospheric CO(2) Cycles at Glacial/Interglacial Timescales

The causes of the glacial cycle remain unknown, although the primary driver is changes in atmospheric CO(2), likely controlled by the biological pump and biogeochemical cycles. The two most important regions of the ocean for exchange of CO(2) with the atmosphere are the equatorial Pacific and the Southern Ocean ( SO), the former a net source and the latter a net sink under present conditions. The equatorial Pacific has been shown to be a Si(OH)(4)-limited ecosystem, a consequence of the low source Si(OH)(4) concentrations in upwelled water that has its origin in the SO. This teleconnection for nutrients between the two regions suggests an oscillatory relationship that may influence or control glacial cycles. Opal mass accumulation rate (MAR) data and delta(15)N measurements in equatorial cores are interpreted with predictions from a one- dimensional Si(OH)(4)-limited ecosystem model (CoSINE) for the equatorial Pacific. The results suggest that equatorial Pacific surface CO(2) processes are in opposite phase to that of the global atmosphere, providing a negative feedback to the glacial cycle. This negative feedback is implemented through the effect of the SO on the equatorial Si(OH)(4) supply. An alternative hypothesis, that the whole ocean becomes Si(OH)(4) poor during cooling periods, is suggested by low opal MAR in cores from both equatorial and Antarctic regions, perhaps as a result of low river input. terminations in this scenario would result from blooms of coccolithophorids triggered by low Si(OH)(4) concentrations.

Co-culture of Notochordal Cells with Nucleus pulposus and Annulus fibrosus cells under normoxia and hypoxia

Introduction Notochordal cells (NC) are shifted back into focus due to their apparent action of activating other disc cells via indirect release of yet unknown factors into the medium (conditioned medium = CM).1,2 Recent evidence confirms the results from the late 1990s.3,4 Here, we test porcine (p) NC cultured in 3D and the influence of adding serum or using serum-free medium onto the culture on NC cells and its stimulating effects for subsequent coculture with primary bovine (b) nucleus pulposus (bNPC) and annulus fibrous cells (bAFC). Materials and Methods Primary pNC, bNPC, and bAFC were isolated from porcine tails (< 6-12 months age) or bovine tails (∼1 year age), which were obtained from the food chain (N = 4 repeats) within 4 hours postmortem. All cells were seeded into 1.2% alginate, each with a density of 4 × 106/mL. NC were then either cultured for 7 days in serum free medium (SFM = Dulbecco modified eagle medium [DMEM] supplied with ITS+, 50 µg/mL vitamin C and nonessential amino acids) or DMEM + 10% fetal calf serum (FCS). CM was produced from NC collecting 4 mL SFM and keeping approximately 30 beads for 7 days. Then, a coculture was set up in SFM for 14 days using indirect cell-cell contact (culture insert, high density pore, 0.4 µm) using a 50:50% ratio5 of pNC:bNP or bAF, or by addition of CM, respectively. The cell activity, glycosaminoglycan per DNA (GAG/DNA) ratio, and real-time RT-PCR of IVD relevant genes were monitored. Mass spectrometry was performed on the SFM and the cocultured medium as well as the CM of the pNC to identify possible key cytokines to the stimulatory effects. Results The results for cell activity confirmed that pNC are highly responsive on the nutritional condition in the culture (K-W test, p = 0.048) after 7 days of coculture. bNPC and bAFC did not respond significantly different to coculture or addition of CM with respect to cell activity. However, GAG/DNA ratio of pNC was significantly upregulated if they were initially pre-exposed to FCS and in coculture with bNPC after 14 days, for both normoxia and hypoxia (K-W, p = 0.03). The bNPC were stimulated by both, 1:1 coculture with pNC but also by addition of CM only, which resulted in approximately 200% increased GAG/DNA values relative to the day 0 state. However, this doubling of the GAG/DNA ratio was nonsignificant after 14 days. The aggrecan/collagen type 2 ratio as quantified from real-time RT-PCR pointed to a beneficial state of the bNPC if cultured either in indirect coculture with pNC or by the addition of CM (Fig. 1). The mass spectrometric analysis of the CM revealed that there was connecting tissue growth factor present (CTGF) among the cytokine CLC11, a cytokine that has been found to be expressed in skeletal tissues including bone marrow and chondrocytes among other factors that might have immunoregulatory and cell proliferative functions.

Exploring sustainability through stakeholders' perspectives and hybrid water in the Swiss alps

Can the concept of water as a socio-natural hybrid and the analysis of different users’ perceptions of water advance the study of water sustainability? In this article, I explore this question by empirically studying sustainability values and challenges, as well as distinct types of water as identified by members of five water user groups in a case study region in the Swiss Alps. Linking the concept of water as a socio-natural hybrid with the different water users’ perspectives provided valuable insights into the complex relations between material, cultural, and discursive practices. In particular, it provided a clearer picture of existing water sustainability challenges and the factors and processes that hinder more sustainable outcomes. However, by focusing on relational processes and individual stakeholder perspectives, only a limited knowledge could be created regarding a) what a more sustainable water future would look like and b) how current unsustainable practices can be effectively transformed into more sustainable ones. I conclude by arguing that the concept of water as a socio-natural hybrid provides an interesting analytical tool for investigating sustainability questions; however, if it is to contribute to water sustainability, it needs to be integrated into a broader transdisciplinary research perspective that understands science as part of a deliberative and reflective process of knowledge co-production and social learning between all actor groups involved.