A coupled isotropic elasto-plastic damage model based on incremental minimization principles

In the present paper, a variational formulation of an isotropic elasto-plastic damage model is proposed. As prototypemodel, a coupled formulation originally introduced by LEMAITRE isconsidered. It is governed b ynon-linear and non-associative evolution equations. The variational approach advocated within the present paper allows to compute all state variables by means of energy minimization. The performance of the proposed framework is illustrated by a comparison between the novel variational method and a standard return-mapping scheme

Determination of nutrient salts by automatic methods both in seawater and brackish water: the phosphate blank

9 páginas, 2 tablas, 2 figurasThe main inconvenience in determining nutrients in seawater by automatic methods is simply solved: the preparation of a suitable blank which corrects the effect of the refractive index change on the recorded signal. Two procedures are proposed, one physical (a simple equation to estimate the effect) and the other chemical (removal of the dissolved phosphorus with ferric hydroxide).Support for this work came from CICYT (MAR88-0245 project) and Conselleria de Pesca de la Xunta de GaliciaPeer reviewe

Toxicology of chemically modified graphene-based materials for medical application.

This review article aims to provide an overview of chemically modified graphene, and graphene oxide (GO), and their impact on toxicology when present in biological systems. Graphene is one of the most promising nanomaterials due to unique physicochemical properties including enhanced optical, thermal, and electrically conductive behavior in addition to mechanical strength and high surface-to-volume ratio. Graphene-based nanomaterials have received much attention over the last 5 years in the biomedical field ranging from their use as polymeric conduits for nerve regeneration, carriers for targeted drug delivery and in the treatment of cancer via photo-thermal therapy. Both in vitro and in vivo biological studies of graphene-based nanomaterials help understand their relative toxicity and biocompatibility when used for biomedical applications. Several studies investigating important material properties such as surface charge, concentration, shape, size, structural defects, and chemical functional groups relate to their safety profile and influence cyto- and geno-toxicology. In this review, we highlight the most recent studies of graphene-based nanomaterials and outline their unique properties, which determine their interactions under a range of environmental conditions. The advent of graphene technology has led to many promising new opportunities for future applications in the field of electronics, biotechnology, and nanomedicine to aid in the diagnosis and treatment of a variety of debilitating diseases

Synthesis of model compounds for the structure elucidation of a ladder polymer from benzo[1,2-c:4,5-c']difuran and a diquinone derivative

Kintzel O, Münch W, Schlüter A-D, Godt A. Synthesis of model compounds for the structure elucidation of a ladder polymer from benzo[1,2-c:4,5-c']difuran and a diquinone derivative. The Journal of Organic Chemistry. 1996;61(21):7304-7308

Reduced Time for Urinary Alkalinization Before High-Dose Methotrexate with Preadmission Oral Bicarbonate

Purpose: Hydration and urinary alkalinization are essential for reducing renal dysfunction with high dose methotrexate (HDMTX). This report presents an analysis of institutional methods used to achieve adequate urinary alkalinization and output for patients receiving single agent HDMTX. Renal and metabolic parameters of tolerance were examined. Methods: Medical records of adult patients receiving HDMTX during the calendar years of 2008–2009 were retrospectively reviewed to determine the time to achieve urine pH\u3e7. Number of hospital days, bicarbonate dose, ordered hydration rate, urine output, and urine pH were assessed. A survival analysis model was run for time to urine pH\u3e7 using preadmission oral bicarbonate as a predictor variable and including a frailty term. Observational statistics were performed for other parameters. Results: The analysis included 79 encounters for ten patients. Urine pH\u3e7 was achieved more rapidly in patients receiving preadmission oral bicarbonate (P¼0.012). The number of patients receiving HDMTX on the same day as admission was greater for those receiving preadmission oral bicarbonate (47%) in comparison to those who did not (2%), and they spent less time in the hospital. A standard regimen for hydration and urinary alkalinization based on this project is reported. The nature and frequency of adverse events were as expected for this treatment. Conclusion: At our institution, the time to achieve urinary alkalinization was reduced for patients receiving preadmission oral bicarbonate which facilitated chemotherapy infusion on the same day as admission and decreased the number of calendar days that patients stayed in the hospital