Synthesis of Redox Polymer Nanoparticles Based on Poly(vinylcatechols) and Their Electroactivity

Organic materials are being investigated as an alternative to inorganic cathodes in lithium batteries with the promise of higher sustainability as well as increased theoretical capacity. Among organic materials, redox polymers based on poly(vinyl catechol) presenting the catechol/o-benzoquinone redox pair show high energy storage potential. Our main motivation in this work was to prepare polymer nanoparticles of different sizes and study their redox properties. As linear polymers are usually soluble/mechanically unstable, we prepared cross-linked polymers to maintain the size of the nanoparticles in different electrolytes. (Mini)emulsion polymerization of two dimethoxy monomers was used to synthesize spherical polymer nanoparticles cross-linked with divinylbenzene (DVB) where the size was controlled by changing the concentration of the surfactant. Deprotection yielded poly(4-vinyl catechol) and poly(3-vinyl catechol) redox active nanoparticles (RPNs) of sizes ranging between 40 and 330 nm as characterized by scanning electron microscopy. The electrochemical properties of the RPN were tested in aqueous- and acetonitrile-based electrolytes using cyclic voltammetry. First the effect of the nanoparticle size and the cross-linker content in the electrochemical properties was investigated. Particle size did not have a crucial effect on the electrochemistry and only the biggest 330 nm RPN showed slightly diminished electrochemical properties. The cross-linker had a negative effect on the maximum reduction current (iC) but improved cycling stability. Based on these results we decided to use the smallest 40 nm nanoparticles with the lowest (1% DVB) cross-linker content for further electrochemical testing. Both RPN isomers showed reversible behavior in aqueous acidic-, neutral-, as well as in acetonitrile-based electrolyte. Poly(4-vinyl catechol)-based RPN had slightly higher reduction potential at 0.45 V versus Ag/AgCl (0.1 M HClO4) compared to another isomer with 0.40 V versus Ag/AgCl. When switching from an acidic aqueous electrolyte to neutral, the redox potential was shifted 440-475 mV to lower values. Because of their high reduction potential and theoretical capacity at 394 mA h/g these synthetic RPNs show promising properties to be used as cathodes in a variety of batteries. However, exact capacity determination, long term cycling, testing in nonaqueous electrolytes, and redox flow batteries needs to be performed in the future.This work was financially supported by the European Research Council by Starting Grant Innovative Polymers for Energy Storage (iPes) 30625 and Slovenian research agency (ARRS): research project J2-8167 and public call MS-ERC-FS/2017-002. N.B. acknowledges the financial support obtained through the Post-Doctoral fellowship Juan de la Cierva-Incorporacion (IJCI-2016-28442), from the Ministry of Economy and Competitiveness of Spain. L.P. has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement no 797295

Unknown primary nasopharyngeal melanoma presenting as severe recurrent epistaxis and hearing loss following treatment and remission of metastatic disease: A case report and literature review

Introduction: Primary nasopharyngeal melanoma is an exceedingly rare pathology with unclear etiology and oftentimes obscure clinical presentation. Despite improved diagnostic capabilities, these lesions are often diagnosed at an advanced stage and associated prognosis is poor, partly due to high rates of recurrences and metastasis. Presentation of case: A 74-year-old woman was diagnosed with metastatic melanoma to the liver, of unknown primary. Just prior to the time of diagnosis, she experienced several episodes of severe epistaxis which she managed conservatively. Her symptoms eventually subsided without further medical evaluation. The patient was initially treated with interleukin-2 (IL-2) for her advanced disease, but her cancer progressed. She was then enrolled in a protocol for percutaneous hepatic perfusion (PHP) with melphalan and had complete radiographic resolution of disease, yet her nosebleeds recurred and persisted despite conservative measures. Six years after her initial diagnosis, a nasopharyngoscopy demonstrated a pigmented lesion in the posterior nasopharynx. Surgical resection was performed (pathology consistent with mucosal melanoma) followed by radiation therapy. She has since had complete resolution of bleeding and shows no evidence of cancer. Discussion: To our knowledge, this is the first report of a diagnosis of primary nasopharyngeal melanoma 6-years following complete remission of metastatic disease. Surgery remains the primary treatment for disease and symptom control in this setting. Conclusion: Timely diagnosis of nasopharyngeal melanomas remains challenging. Thorough clinical evaluations should be performed in such patients, and attention should be paid to recurrent and persistent symptoms, such as epistaxis and hearing loss. This may allow for earlier detection of primary disease

Electronic lab notebooks: can they replace paper?

Despite the increasingly digital nature of society there are some areas of research thatremain firmly rooted in the past; in this case the laboratory notebook, the last remaining paper component of an experiment. Countless Electronic Laboratory Notebooks (ELNs) have been created in an attempt to digitise record keeping processes in the lab, but none of them have become a 'key player' in the ELN market, due to the many adoption barriers that have been identified in previous research and further explored in the user studies presented here. The main issues identified are the cost of the current available ELNs, their ease of use (or lack of it) and their accessibility issues across different devices and operating systems. Evidence suggests that whilst scientists willingly make use of generic notebooking software, spreadsheets and other general office & scientific tools to aid their work, current ELNs are lacking in the required functionality to meet the needs of the researchers. In this paper we present our extensive research and user study results to propose an ELN built upon a pre-existing cloud notebook platform that makes use of accessible popular scientific software and Semantic web technologies to help overcome the identified barriers to adoption

MOESM1 of Electronic lab notebooks: can they replace paper?

Additional file 1. A file describing how to access the focus groups and lab observations transcripts from Study D—University of Southampton Lab Practice Study (Focus Groups & Lab Observations)

Diabetes-induced oxidative stress in the vitreous humor

Purpose: Diabetes is accompanied by fundamental rearrangements in redox homeostasis. Hyperglycemia triggers the production of reactive oxygen and nitrogen species which contributes to tissue damage in various target organs. Proliferative diabetic retinopathy (PDR) is a common manifestation of diabetic complications but information on the possible role of reactive intermediates in this condition with special regard to the involvement of the vitreous in PDR-associated redox alterations is scarce. The aim of the study was to determine key parameters of redox homeostasis [advanced glycation endproducts (AGE); protein carbonyl and glutathione (GSH)] content in the vitreous in PDR patients. Methods: The study population involved 10 diabetic patients undergoing surgery for complications of proliferative diabetic retinopathy and 8 control (non-diabetic) patients who were undergoing surgery for epiretinal membranes. Vitreal fluids were assayed for the above biochemical parameters. Results: We found elevated levels of AGE in the vitreous of PDR patients (812.10 vs 491.69 ng AGE/mg protein). Extent of protein carbonylation was also higher in the samples of diabetic patients (2.08 vs 0.67 A/100 μg protein). The GSH content also increased in the vitreous of PDR patients as compared to the control group (4.54 vs 2.35 μmol/μg protein), respectively. Conclusion: The study demonstrates that diabetes-associated redox alterations also reach the vitreous with the most prominent changes being increased protein carbonylation and increased antioxidant levels