Freely dissolved pore water concentrations and sorption coefficients of PAHs in spiked, aged, and field-contaminated soils

Freely dissolved aqueous concentrations in the soil pore water represent an important aspect of bioavailability and risk assessment of contaminated soils. In this study, a negligible depletive partitioning based sampling technique was validated and applied to measure free concentrations of polycyclic aromatic hydrocarbons (PAHs) in spiked, aged and field-contaminated soils. Detailed kinetic studies were performed to select appropriate equilibration times. Freely dissolved aqueous concentrations in the pore water were compared to total concentrations, and sorption coefficients were calculated. Results show that equilibrium partition models can predict sorption coefficients of freshly spiked and lab-aged soils rather accurately. However, freely dissolved pore water concentrations of field-contaminated soils are orders of magnitude lower than model predictions. Consequently, environmental risks can be highly overestimated with these models. The simple and sensitive partitioning-based sampling technique used in this study, could, therefore, be applicable to improve site-specific risk assessment of field-contaminated soils.     

Solid-phase microextraction to predict bioavailability and accumulation of organic micropollutants in terrestrial organisms after exposure to a field-contaminated soil

The risk posed by soil contaminants strongly depends on their bioavailability. In this study, a partition-based sampling method was applied as a tool to estimate bioavailability in soil. The accumulation of organic micropollutants was measured in two earthworm species (Eisenia andrei and Aporrectodea caliginosa) and in 30-microm poly(dimethylsiloxane) (PDMS)-coated solid-phase micro extraction (SPME) fibers after exposure to two field-contaminated soils. Within 10 days, steady state in earthworms was reached, and within 20 days in the SPME fibers. Steady-state concentrations in both earthworm species were linearly related to concentrations in fibers over a 10,000-fold range of concentrations. Measured concentrations in earthworms were compared to levels calculated via equilibrium partitioning theory and total concentrations of contaminants in soil. In addition, freely dissolved concentrations of contaminants in pore water, derived from SPME measurements, were used to calculate concentrations in earthworms. Measured concentrations in earthworms were close to estimated concentrations from the SPME fiber measurements. Freely dissolved concentrations of contaminants in pore water, derived from SPME measurements, were used to calculate bioconcentration factors (BCF) in earthworms. A plot of log BCFs against the octanol-water partition coefficient (log Kow) was linear up to a log Kow of 8. These results show that measuring concentrations of hydrophobic chemicals in a PDMS-coated fiber represents a simple tool to estimate internal concentrations of chemicals in biota exposed to soil.     

Influence of the uterine environment on the development of in vitro-produced equine embryos

The necessity for early interaction between the embryo and the oviductal and/or uterine environment in the horse is reflected by several striking differences between equine embryos that develop in vivo and those produced in vitro. Better understanding of the salient interactions may help to improve the efficiency of in vitro equine embryo production. In an initial experiment, cleavage-stage in vitro-produced (IVP) equine embryos were transferred into the uterus of recipient mares that had ovulated recently to determine whether premature placement in this in vivo environment would improve subsequent development. In a second experiment, an important element of the uterine environment was mimicked by adding uterocalin, a major component of the endometrial secretions during early pregnancy, to the culture medium. Intrauterine transfer of cleavage-stage IVP equine embryos yielded neither ultrasonographically detectable pregnancies nor day 7 blastocysts, indicating that the uterus is not a suitable environment for pre-compact morula stage horse embryos. By contrast, exposure to uterocalin during IVP improved capsule formation, although it did not measurably affect the development or expression of a panel of genes known to differ between in vivo and in vitro embryos. Further studies are required to evaluate whether uterocalin serves purely as a carrier protein or more directly promotes improved capsule development.     

Dendritic Cell-Based Immunotherapy in Multiple Myeloma: Challenges,Opportunities, and Future Directions

Immunotherapeutic approaches, including adoptive cell therapy, revolutionized treatment in multiple myeloma (MM). As dendritic cells (DCs) are professional antigen-presenting cells and key initiators of tumor-specific immune responses, DC-based immunotherapy represents an attractive therapeutic approach in cancer. The past years, various DC-based approaches, using particularly ex-vivo-generated monocyte-derived DCs, have been tested in preclinical and clinical MM studies. However, long-term and durable responses in MM patients were limited, potentially attributed to the source of monocyte-derived DCs and the immunosuppressive bone marrow microenvironment. In this review, we briefly summarize the DC development in the bone marrow niche and the phenotypical and functional characteristics of the major DC subsets. We address the known DC deficiencies in MM and give an overview of the DC-based vaccination protocols that were tested in MM patients. Lastly, we also provide strategies to improve the efficacy of DC vaccines using new, improved DC-based approaches and combination therapies for MM patients.     

Influence of Argon on the Phase Behavior and Vibrational Properties of Solid Nitrogen at High Pressure

The mixed solid N ₂–Ar has been studied at high pressure at the nitrogen–rich side of the phase diagram by Raman spectroscopy. The argon atoms dissolve into some of the nitrogen structures. Within the *–phase the Ar–-atoms are mainly located at the sphere–like disordered sites in agreement with computer simulations. The second order transition of pure N ₂ is still present in the mixed solid at 25 mole% Ar. The * – * and *–fluid transitions in the mixed solid are shifted compared to the pure system. The phase diagram of the mixture for x[N ₂]0.75 has been studied.     

Thrombolytic therapy does not change the release ratios of enzymatic and non-enzymatic myocardial marker proteins

Measurements of cardiac marker proteins in plasma from patients with acute myocardial infarction (AMI) have become important in the evaluation of recanalization therapy. The validity of this approach has however been questioned, because it was claimed that coronary reperfusion may increase the recovery in plasma of cardiac enzymes, such as creatine kinase (CK). In the present study, possible effects of thrombolytic therapy on the release of enzymatic and nonenzymatic marker proteins were investigated. Activities of CK and lactate dehydrogenase (LDH), and concentrations of myoglobin (Mb) and fatty acid-binding protein (FABP) were determined in serial plasma samples obtained from 50 patients with confirmed AMI, of whom 36 received thrombolytic therapy, and 14 did not. Treatment delay was 2.8+/-1.6 (mean+/-SD) h, and hospital delay in untreated patients was 2.7+/-1.8 h. Average infarct size, expressed in gram-equivalents of heart muscle per litre of plasma (g-eq/l), varied between 5.5 and 7.2 g-eq/l for the four marker proteins in patients treated with thrombolytic therapy, and between 4.6 and 6.4 g-eq/l in untreated patients, with a tendency to larger infarct sizes for Mb and FABP than for CK and LDH. Thrombolytic therapy, although significantly accelerating protein release rates, did not influence the release ratios. These results indicate that thrombolytic therapy has no significant effects on the recovery of cardiac marker proteins in plasma.     

Knowledge Exchange in Strategic Alliances: Learning in Tension

The proliferation of corporate strategic alliances is explained by the opportunities this provides for the exchange of knowledge and more rapid learning than any other factor. Exploiting complementarities among products and services, strategic alliances enable value creation by capturing the benefits from leveraging knowledge, and discovering complementarities among technologies, and among the activities of the participants. This paper explores the relevance of factors, which may influence the relationship involving the imbalances of internal tensions and alliance instabilities. It is assumed that the objective in a strategic alliance partnership is to maintain the collaborative relationship and to prevent unplanned alliance dissolution. Factors such as availability of resources, bargaining power, alliance type, alliances with specific goals and stages of industry life cycles, and changing market conditions can influence internal tensions and therefore alliance stability. This article argues that alliance partners should balance the conflicting forces to maintain the collaborative knowledge creating and learning relationship.     

Conceptual process design of extractive distillation processes for ethylbenzene/styrene separation

In the current styrene production process the distillation of the close-boiling ethylbenzene/styrene mixture to obtain an ethylbenzene impurity level of 100 ppm in styrene accounts for 75–80% of the energy requirements. The future target is to reach a level of 1–10 ppm, which will increase the energy requirements for the distillation even further. Extractive distillation is a well-known technology to separate close-boiling mixtures up to high purities. The objective of this study was to investigate whether extractive distillation using ionic liquids (ILs) is a promising alternative to obtain high purity styrene. Three ILs were studied: [3-mebupy][B(CN)₄], [4-mebupy][BF₄], and [EMIM][SCN]. Extractive distillation with sulfolane and the current conventional distillation process were used as benchmark processes. The IL [4-mebupy][BF₄] is expected to outperform the other two ILs with up to 11.5% lower energy requirements. The operational expenditures of the [4-mebupy][BF₄] process are found to be 43.2% lower than the current distillation process and 5% lower than extractive distillation with sulfolane extractive distillations. However, the capital expenditures for the sulfolane process will be about 23% lower than those for the [4-mebupy][BF₄] process. Finally, the conclusion can be drawn from the total annual costs that all studied extractive distillation processes outperform the current distillation process to obtain high purity styrene, but that the ILs evaluated will not perform better than sulfolane.