Dual Band Electrodes in Generator-Collector Mode: Simultaneous Measurement of Two Species

A computational model for the simulation of a double band collector-generator experiment is applied to the situation where two electrochemical reactions occur concurrently. It is shown that chronoamperometric measurements can be used to take advantage of differences in diffusion coefficients to measure the concentrations of both electroactive species simultaneously, by measuring the time at which the collection efficiency reaches a specific value. The separation of the electrodes is shown to not affect the sensitivity of the method (in terms of percentage changes in the measured time to reach the specified collection efficiency), but wider gaps can provide a greater range of (larger) absolute values of this characteristic time. It is also shown that measuring the time taken to reach smaller collection efficiencies can allow for the detection of smaller amounts of whichever species diffuses faster. The case of a system containing both ascorbic acid and opamine in water is used to exemplify the method, and it is shown that mole fractions of ascorbic acid between 0.055 and 0.96 can, in principle, be accurately measured.Comment: 34 pages, 8 figure

Endothelial barrier disruption by VEGF-mediated Src activity potentiates tumor cell extravasation and metastasis

VEGF is unique among angiogenic growth factors because it disrupts endothelial barrier function. Therefore, we considered whether this property of VEGF might contribute to tumor cell extravasation and metastasis. To test this, mice lacking the Src family kinases Src or Yes, which maintain endothelial barrier function in the presence of VEGF, were injected intravenously with VEGF-expressing tumor cells. We found a dramatic reduction in tumor cell extravasation in lungs or livers of mice lacking Src or Yes. At the molecular level, VEGF compromises the endothelial barrier by disrupting a VE-cadherin–β-catenin complex in lung endothelium from wild-type, but not Yes-deficient, mice. Disrupting the endothelial barrier directly with anti–VE-cadherin both amplifies metastasis in normal mice and overcomes the genetic resistance in Yes-deficient mice. Pharmacological blockade of VEGF, VEGFR-2, or Src stabilizes endothelial barrier function and suppresses tumor cell extravasation in vivo. Therefore, disrupting Src signaling preserves host endothelial barrier function providing a novel host-targeted approach to control metastatic disease

The acceleration of urban sustainability transitions: a comparison of Brighton, Budapest, Dresden, Genk, and Stockholm

City-regions as sites of sustainability transitions have remained under-explored so far. With our comparative analysis of five diverse European city-regions, we offer new insights on contemporary sustainability transitions at the urban level. In a similar vein, the pre-development and the take-off phase of sustainability transitions have been studied in depth while the acceleration phase remains a research gap. We address this research gap by exploring how transitions can move beyond the seeding of alternative experiments and the activation of civil society initiatives. This raises the question of what commonalities and differences can be found between urban sustainability transitions. In our explorative study, we employ a newly developed framework of the acceleration mechanisms of sustainability transitions. We offer new insights on the multi-phase model of sustainability transitions. Our findings illustrate that there are no clear demarcations between the phases of transitions. From the perspective of city-regions, we rather found dynamics of acceleration, deceleration, and stagnation to unfold in parallel. We observed several transitions—transitions towards both sustainability and un-sustainability—to co-evolve. This suggests that the politics of persistence—the inertia and path dependencies of un-sustainability—should be considered in the study of urban sustainability transition

ExpiSf™: A chemically-defined baculovirus-based expression system for enhanced Protein production in Sf9 cells

The Baculovirus Expression Vector System (BEVS) is one of the major platforms for recombinant protein production and the last decade has become a preferred platform for vaccine development. Unlike mammalian expression systems that have long since transitioned to serum-free, chemically-defined culture media, relatively little innovation has taken place in insect expression systems, with insect cells continuing to rely on undefined, yeastolate-containing culture media that can exhibit significant lot-to-lot variability in terms of both cell growth and protein expression. Here, we present the development of a novel Sf9-based Baculovirus expression system based on a high-density, chemically-defined culture medium, a high-expressing Sf9 cell line, improved transfection reagent to faster generation of baculoviruses and expression enhancer that allow for consistent production of recombinant proteins with two-fold or greater improvements in protein titers compared to traditional BEVS workflows

Developing Core Sets for Persons With Traumatic Brain Injury Based on the International Classification of Functioning, Disability, and Health

The authors outline the process for developing the International Classification of Functioning, Disability, and Health (ICF) Core Sets for traumatic brain injury (TBI). ICF Core Sets are selections of categories of the ICF that identify relevant categories of patients affected by specific diseases. Comprehensive and brief ICF Core Sets for TBI should become useful for clinical practice and for research. The final definition of the ICF Core Sets for TBI will be determined at an ICF Core Sets Consensus Conference, which will integrate evidence from preliminary studies. The development of ICF Core Sets is an inclusive and open process and rehabilitation professionals are invited to participate

Functional Modeling Identifies Paralogous Solanesyl-diphosphate Synthases That Assemble the Side Chain of Plastoquinone-9 in Plastids

Background: Plastid isoforms of solanesyl-diphosphate synthase catalyze the elongation of the prenyl side chain of plastoquinone-9. Results: Corresponding mutants display lower levels of plastoquinone-9 and plastochromanol-8 and display intact levels of vitamin E. Conclusion: Plastochromanol-8 originates from a subfraction of non-photoactive plastoquinol-9 and is not essential for seed longevity. Significance: Viable plastoquinone-9 mutants are invaluable tools for understanding plastid metabolism

An asteroidal origin for water in the Moon

The Apollo-derived tenet of an anhydrous Moon has been contested following measurement of water in several lunar samples that require water to be present in the lunar interior. However, significant uncertainties exist regarding the flux, sources and timing of water delivery to the Moon. Here we address those fundamental issues by constraining the mass of water accreted to the Moon and modelling the relative proportions of asteroidal and cometary sources for water that are consistent with measured isotopic compositions of lunar samples. We determine that a combination of carbonaceous chondrite-type materials were responsible for the majority of water (and nitrogen) delivered to the Earth–Moon system. Crucially, we conclude that comets containing water enriched in deuterium contributed significantly <20% of the water in the Moon. Therefore, our work places important constraints on the types of objects impacting the Moon ~4.5–4.3 billion years ago and on the origin of water in the inner Solar System