Electroactive biofilms: new means for electrochemistry

This work demonstrates that electrochemical reactions can be catalysed by the natural biofilms that form on electrode surfaces dipping into drinking water or compost. In drinking water, oxygen reduction was monitored with stainless steel ultra-microelectrodes under constant potential electrolysis at )0.30 V/SCE for 13 days. 16 independent experiments were conducted in drinking water, either pure or with the addition of acetate or dextrose. In most cases, the current increased and reached 1.5–9.5 times the initial current. The current increase was attributed to biofilm forming on the electrode in a similar way to that has been observed in seawater. Epifluorescence microscopy showed that the bacteria size and the biofilm morphology depended on the nutrients added, but no quantitative correlation between biofilm morphology and current was established. In compost, the oxidation process was investigated using a titanium based electrode under constant polarisation in the range 0.10–0.70 V/SCE. It was demonstrated that the indigenous micro-organisms were responsible for the current increase observed after a few days, up to 60 mA m)2. Adding 10 mM acetate to the compost amplified the current density to 145 mA m)2 at 0.50 V/SCE. The study suggests that many natural environments, other than marine sediments, waste waters and seawaters that have been predominantly investigated until now, may be able to produce electrochemically active biofilm

REMOVED: Optimization of VMD Process as Draw Solution Recovery Unit in FO Process

This article has been removed: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy).This article has been removed at the request of the Executive Publisher.This article has been removed because it was published without the permission of the author(s)

Systems Level Modeling of the Cell Cycle Using Budding Yeast

Proteins involved in the regulation of the cell cycle are highly conserved across all eukaryotes, and so a relatively simple eukaryote such as yeast can provide insight into a variety of cell cycle perturbations including those that occur in human cancer. To date, the budding yeast Saccharomyces cerevisiae has provided the largest amount of experimental and modeling data on the progression of the cell cycle, making it a logical choice for in-depth studies of this process. Moreover, the advent of methods for collection of high-throughput genome, transcriptome, and proteome data has provided a means to collect and precisely quantify simultaneous cell cycle gene transcript and protein levels, permitting modeling of the cell cycle on the systems level. With the appropriate mathematical framework and sufficient and accurate data on cell cycle components, it should be possible to create a model of the cell cycle that not only effectively describes its operation, but can also predict responses to perturbations such as variation in protein levels and responses to external stimuli including targeted inhibition by drugs. In this review, we summarize existing data on the yeast cell cycle, proteomics technologies for quantifying cell cycle proteins, and the mathematical frameworks that can integrate this data into representative and effective models. Systems level modeling of the cell cycle will require the integration of high-quality data with the appropriate mathematical framework, which can currently be attained through the combination of dynamic modeling based on proteomics data and using yeast as a model organism

Upregulation and function of GADD45γ in unilateral ureteral obstruction

We performed differential display analysis to determine transcriptional activity in the rat kidney, following unilateral ureteral obstruction and found a 12-fold increase in the expression of Growth Arrest and DNA Damage-45γ (GADD45γ), a stress-responsive molecule that interacts with cell-cycle proteins. GADD45γ was strongly expressed in as little as 6 h following ureteric obstruction in the renal tubules, and was also found in kidney tissue of patients with chronic glomerulonephritis. Adenovirus-mediated expression of GADD45γ in cultured renal tubular cells activated p38 along with a significant upregulation of C–C and C–X3–C chemokine ligands and fibrosis-related factors such as several matrix metalloproteinases, transforming growth factor-β1, decorin, and bone morphogenetic protein 2. Silencing of GADD45γ expression significantly blunted the upregulation of these inflammatory and fibrogenic mediators and monocyte infiltration in the ureteral obstructed rat kidney. Our study shows that GADD45γ is quickly upregulated in the kidney with an obstructed ureter, enhancing the production of factors regulating the pathogenesis of kidney disease

Controlled Growth, Patterning and Placement of Carbon Nanotube Thin Films

Controlled growth, patterning and placement of carbon nanotube (CNT) thin films for electronic applications are demonstrated. The density of CNT films is controlled by optimizing the feed gas composition as well as the concentration of growth catalyst in a chemical vapor deposition process. Densities of CNTs ranging from 0.02 CNTs/{\mu}m^2 to 1.29 CNTs/{\mu}m^2 are obtained. The resulting pristine CNT thin films are then successfully patterned using either pre-growth or post-growth techniques. By developing a layered photoresist process that is compatible with ferric nitrate catalyst, significant improvements over popular pre-growth patterning methods are obtained. Limitations of traditional post-growth patterning methods are circumvented by selective transfer printing of CNTs with either thermoplastic or metallic stamps. Resulting as-grown patterns of CNT thin films have edge roughness (< 1 {\mu}m) and resolution (< 5 {\mu}m) comparable to standard photolithography. Bottom gate CNT thin film devices are fabricated with field-effect mobilities up to 20 cm^2/Vs and on/off ratios of the order of 10^3. The patterning and transfer printing methods discussed here have a potential to be generalized to include other nanomaterials in new device configurations

Penrose Limits of Orbifolds and Orientifolds

We study the Penrose limit of various AdS_p X S^q orbifolds. The limiting spaces are waves with parallel rays and singular wave fronts. In particular, we consider the orbifolds AdS_3 X S^3/\Gamma, AdS_5 X S^5/\Gamma and AdS_{4,7} X S^{7,4}/\Gamma where \Gamma acts on the sphere and/or the AdS factor. In the pp-wave limit, the wave fronts are the orbifolds C^2/\Gamma, C^4/\Gamma and R XC^4/\Gamma, respectively. When desingularization is possible, we get asymptotically locally pp-wave backgrounds (ALpp). The Penrose limit of orientifolds are also discussed. In the AdS_5 X RP^5 case, the limiting singularity can be resolved by an Eguchi-Hanson gravitational instanton. The pp-wave limit of D3-branes near singularities in F-theory is also presented. Finally, we give the embedding of D-dimensional pp-waves in flat M^{2,D} space.Comment: 20 pages, references adde

Scaling determination of the nonlinear I-V characteristics for 2D superconducting networks

It is shown from computer simulations that the current-voltage ($I$-$V$) characteristics for the two-dimensional XY model with resistively-shunted Josephson junction dynamics and Monte Carlo dynamics obeys a finite-size scaling form from which the nonlinear $I$-$V$ exponent $a$ can be determined to good precision. This determination supports the conclusion $a=z+1$, where $z$ is the dynamic critical exponent. The results are discussed in the light of the contrary conclusion reached by Tang and Chen [Phys. Rev. B {\bf 67}, 024508 (2003)] and the possibility of a breakdown of scaling suggested by Bormann [Phys. Rev. Lett. {\bf 78}, 4324 (1997)].Comment: 6 pages, to appear in PR

A Comparison of the Quick Sequential (Sepsis-Related) Organ Failure Assessment Score and the National Early Warning Score in Non-ICU Patients With/Without Infection.

OBJECTIVES: The Sepsis-3 task force recommended the quick Sequential (Sepsis-Related) Organ Failure Assessment score for identifying patients with suspected infection who are at greater risk of poor outcomes, but many hospitals already use the National Early Warning Score to identify high-risk patients, irrespective of diagnosis. We sought to compare the performance of quick Sequential (Sepsis-Related) Organ Failure Assessment and National Early Warning Score in hospitalized, non-ICU patients with and without an infection. DESIGN: Retrospective cohort study. SETTING: Large U.K. General Hospital. PATIENTS: Adults hospitalized between January 1, 2010, and February 1, 2016. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: We applied the quick Sequential (Sepsis-Related) Organ Failure Assessment score and National Early Warning Score to 5,435,344 vital signs sets (241,996 hospital admissions). Patients were categorized as having no infection, primary infection, or secondary infection using International Classification of Diseases, 10th Edition codes. National Early Warning Score was significantly better at discriminating in-hospital mortality, irrespective of infection status (no infection, National Early Warning Score 0.831 [0.825-0.838] vs quick Sequential [Sepsis-Related] Organ Failure Assessment 0.688 [0.680-0.695]; primary infection, National Early Warning Score 0.805 [0.799-0.812] vs quick Sequential [Sepsis-Related] Organ Failure Assessment 0.677 [0.670-0.685]). Similarly, National Early Warning Score performed significantly better in all patient groups (all admissions, emergency medicine admissions, and emergency surgery admissions) for all outcomes studied. Overall, quick Sequential (Sepsis-Related) Organ Failure Assessment performed no better, and often worse, in admissions with infection than without. CONCLUSIONS: The National Early Warning Score outperforms the quick Sequential (Sepsis-Related) Organ Failure Assessment score, irrespective of infection status. These findings suggest that quick Sequential (Sepsis-Related) Organ Failure Assessment should be reevaluated as the system of choice for identifying non-ICU patients with suspected infection who are at greater risk of poor outcome