Mercury(II) Extraction Using a Poly(3,4-Ethylenedioxythiophene) Modified Electrode

Poly(3,4-ethylenedioxythiophene), PEDOT, electro-obtention has been widely studied because of its variety of applications. One of its most relevant electrochemical characteristics is its ability of p- and n-doping (an almost unexplored property thus far), consequently in the present survey its potential use for mercury(II) extraction, based on n-doping process, was studied. To this end EDOT was potentiostatically electro-polymerized on steel (AISI 316, 6 cm²) as substrate employing lithium perchlorate as supporting electrolyte and CH3CN as solvent. Each extraction cycle consisted of immersing the PEDOT modified electrode into a solution made of 1 mM Hg(II) and phosphate buffer at physiological pH (PBS). The n-doping potential was then applied for 5 min to incorporate the cation into the polymer matrix. Subsequently, to remove the cation, n-undoping potential was applied for 5 min to the electrode immersed into another cell containing only PBS. In the current survey, the extraction process required 25 successive cycles to achieve 100% yield. XPS spectra confirmed that the metal was always in its +2 oxidation state, confirming that the extraction occurs only through a n-doping/undoping process. Thus, it was verified for the first time that this property of conductive polymers can be utilized to separate (extract or remove) cations (in this case Hg(II)), using a cheap and simple method that, among others, may have great utility in areas of environmental and/or toxicological interest

Plasma Vitamin C and Cancer Mortality in Kidney Transplant Recipients

There is a changing trend in mortality causes in kidney transplant recipients (KTR), with a decline in deaths due to cardiovascular causes along with a relative increase in cancer mortality rates. Vitamin C, a well-known antioxidant with anti-inflammatory and immune system enhancement properties, could offer protection against cancer. We aimed to investigate the association of plasma vitamin C with long-term cancer mortality in a cohort of stable outpatient KTR without history of malignancies other than cured skin cancer. Primary and secondary endpoints were cancer and cardiovascular mortality, respectively. We included 598 KTR (mean age 51 +/- 12 years old, 55% male). Mean (SD) plasma vitamin C was 44 +/- 20 mu mol/L. At a median follow-up of 7.0 (IQR, 6.2-7.5) years, 131 patients died, of which 24% deaths were due to cancer. In Cox proportional hazards regression analyses, vitamin C was inversely associated with cancer mortality (HR 0.50; 95%CI 0.34-0.74; p <0.001), independent of potential confounders, including age, smoking status and immunosuppressive therapy. In secondary analyses, vitamin C was not associated with cardiovascular mortality (HR 1.16; 95%CI 0.83-1.62; p = 0.40). In conclusion, plasma vitamin C is inversely associated with cancer mortality risk in KTR. These findings underscore that relatively low circulating plasma vitamin C may be a meaningful as yet overlooked modifiable risk factor of cancer mortality in KTR

She\u27s So Bubbly

We introduce the Automatic Learning for the Rapid Classification of Events (ALeRCE) broker, an astronomical alert broker designed to provide a rapid and self-consistent classification of large etendue telescope alert streams, such as that provided by the Zwicky Transient Facility (ZTF) and, in the future, the Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST). ALeRCE is a Chilean-led broker run by an interdisciplinary team of astronomers and engineers working to become intermediaries between survey and follow-up facilities. ALeRCE uses a pipeline that includes the real-time ingestion, aggregation, cross-matching, machine-learning (ML) classification, and visualization of the ZTF alert stream. We use two classifiers: a stamp-based classifier, designed for rapid classification, and a light curve–based classifier, which uses the multiband flux evolution to achieve a more refined classification. We describe in detail our pipeline, data products, tools, and services, which are made public for the community (see https://alerce.science). Since we began operating our real-time ML classification of the ZTF alert stream in early 2019, we have grown a large community of active users around the globe. We describe our results to date, including the real-time processing of 1.5 × 10⁸ alerts, the stamp classification of 3.4 × 10⁷ objects, the light-curve classification of 1.1 × 10⁶ objects, the report of 6162 supernova candidates, and different experiments using LSST-like alert streams. Finally, we discuss the challenges ahead in going from a single stream of alerts such as ZTF to a multistream ecosystem dominated by LSST

Freeze-Drying of Mononuclear Cells Derived from Umbilical Cord Blood Followed by Colony Formation

BACKGROUND: We recently showed that freeze-dried cells stored for 3 years at room temperature can direct embryonic development following cloning. However, viability, as evaluated by membrane integrity of the cells after freeze-drying, was very low; and it was mainly the DNA integrity that was preserved. In the present study, we improved the cells' viability and functionality after freeze-drying. METHODOLOGY/PRINCIPAL FINDINGS: We optimized the conditions of directional freezing, i.e. interface velocity and cell concentration, and we added the antioxidant EGCG to the freezing solution. The study was performed on mononuclear cells (MNCs) derived from human umbilical cord blood. After freeze-drying, we tested the viability, number of CD34(+)-presenting cells and ability of the rehydrated hematopoietic stem cells to differentiate into different blood cells in culture. The viability of the MNCs after freeze-drying and rehydration with pure water was 88%-91%. The total number of CD34(+)-presenting cells and the number of colonies did not change significantly when evaluated before freezing, after freeze-thawing, and after freeze-drying (5.4 x 10(4)+/-4.7, 3.49 x 10(4)+/-6 and 6.31 x 10(4)+/-12.27 cells, respectively, and 31+/-25.15, 47+/-45.8 and 23.44+/-13.3 colonies, respectively). CONCLUSIONS: This is the first report of nucleated cells which have been dried and then rehydrated with double-distilled water remaining viable, and of hematopoietic stem cells retaining their ability to differentiate into different blood cells

Metaheuristics for Transmission Network Expansion Planning

This chapter presents the characteristics of the metaheuristic algorithms used to solve the transmission network expansion planning (TNEP) problem. The algorithms used to handle single or multiple objectives are discussed on the basis of selected literature contributions. Besides the main objective given by the costs of the transmission system infrastructure, various other objectives are taken into account, representing generation, demand, reliability and environmental aspects. In the single-objective case, many metaheuristics have been proposed, in general without making strong comparisons with other solution methods and without providing superior results with respect to classical mathematical programming. In the multi-objective case, there is a better convenience of using metaheuristics able to handle conflicting objectives, in particular with a Pareto front-based approach. In all cases, improvements are still expected in the definition of benchmark functions, benchmark networks and robust comparison criteria

Concept mapping as a means of requirements tracing

Requirements documents often describe the system on different abstraction levels. This results in the fact that the same issues may be described in different documents and with different vocabulary. For analysts who are new to the application domain, this poses a major orientation problem, as they cannot link different concepts or documents with each other. In the presented paper, we propose an approach to map concepts extracted from different documents to each other. This, in turn, allows us to find related passages in different documents, even though the documents represent different levels of abstraction. Practical applicability of the approach was proven in a case study with real-world requirements documents

Making tacit requirements explicit

The importance of tacit knowledge in Requirements Engineering (RE) is widely acknowledged. While valuable work has developed techniques to expose sources of tacit knowledge during requirements elicitation, such techniques are not universally applied and tacit knowledge, continues to negatively affect the quality of the requirements. In this position paper we present a brief review and interpretation of the literature on tacit knowledge that, we believe, is useful for RE. We describe a number of techniques that offer analysts the means to reason about the effect of tacit knowledge and improve the quality of requirements and their management

Making Tacit Requirements Explicit

The importance of tacit knowledge in Requirements Engineering (RE) is widely acknowledged. While valuable work has developed techniques to expose sources of tacit knowledge during requirements elicitation, such techniques are not universally applied and tacit knowledge, continues to negatively affect the quality of the requirements. In this position paper we present a brief review and interpretation of the literature on tacit knowledge that, we believe, is useful for RE. We describe a number of techniques that offer analysts the means to reason about the effect of tacit knowledge and improve the quality of requirements and their management