Gelation of Cellulose Derivatives: Searching for ionic liquid paper

Cellulose is the world’s most abundant, biocompatible, non-toxic, biodegradable polymer obtained from renewable sources. However its dissolution problems hampers a more generalized application. ILs are generally defined as organic/inorganic salts with a melting point lower than 100 C which present a good solubility for polar and non-polar compounds such as organic, inorganic or polymeric materials like cellulose. Cellulose solvents are scarce and, as such, the modification of its properties is a challenge. In this dissertation the main goal was to combine some of the unique IL’s properties with the intrinsic cellulose features. Thus, our strategy was to synthesize cellulose derivatives that enable the dissolution process in order to, later on, obtain a polymer gel. In the first stage we obtained ionic liquid grafted cellulose derivatives. Afterwards, we performed an extensive solubilization study to select the appropriate conditions to obtain the gel state. To further understand the solvents’ dynamics and their relevance in the gelation process, these conditions were followed by NMR and Rheology. The obtained results allowed the proposal of a gelation model for these cellulosic polymers. The proposed strategy could be a starting point to design and produce Ionic Liquid Paper (ILP), a material that could have potential for electrochemical applications

Tensile and hydraulic properties of geosynthetics after mechanical damage and abrasion laboratory tests

Installation damage of geosynthetics occurs during their handling, positioning on the ground and the placing and compacting of fill material. Abrasion is a common damage mechanism where there is cyclic relative motion (friction) between a geosynthetic and contact soil. This paper presents the laboratory test results of mechanical damage and abrasion performed on six geosynthetics. The in isolation and combined effects on mechanical, hydraulic and physical properties of the geosynthetics were assessed. Results show that the effects of induced mechanical and abrasion damage essentially depend on the geosynthetic structure. For the most affected materials, strength losses after abrasion (in isolation and combined with mechanical damage) are higher than after the induced mechanical damage. Therefore, for most geosynthetics studied, abrasion is the conditioning mechanism which most affects their tensile strength. An increase of the characteristic opening size of the geosynthetics was observed, while their permittivity did not increase. This may be caused by differences in the test set-ups

Infinite-dimensional representations of the rotation group and Dirac's monopole problem

Within the context of infinite-dimensional representations of the rotation group the Dirac monopole problem is studied in details. Irreducible infinite-dimensional representations, being realized in the indefinite metric Hilbert space, are given by linear unbounded operators in infinite-dimensional topological spaces, supplied with a weak topology and associated weak convergence. We argue that an arbitrary magnetic charge is allowed, and the Dirac quantization condition can be replaced by a generalized quantization rule yielding a new quantum number, the so-called topological spin, which is related to the weight of the Dirac string.Comment: JHEP style. Extended version of hep-th/0403146. Revised version, title and some notations are changed. References and Appendix B are adde

Current advances of nitric oxide in cancer and anticancer therapeutics

Nitric oxide (NO) is a short-lived, ubiquitous signaling molecule that affects numerous critical functions in the body. There are markedly conflicting findings in the literature regarding the bimodal effects of NO in carcinogenesis and tumor progression, which has important consequences for treatment. Several preclinical and clinical studies have suggested that both pro- and antitumorigenic effects of NO depend on multiple aspects, including, but not limited to, tissue of generation, the level of production, the oxidative/reductive (redox) environment in which this radical is generated, the presence or absence of NO transduction elements, and the tumor microenvironment. Generally, there are four major categories of NO-based anticancer therapies: NO donors, phosphodiesterase inhibitors (PDE-i), soluble guanylyl cyclase (sGC) activators, and immunomodulators. Of these, NO donors are well studied, well characterized, and also the most promising. In this study, we review the current knowledge in this area, with an emphasis placed on the role of NO as an anticancer therapy and dysregulated molecular interactions during the evolution of cancer, highlighting the strategies that may aid in the targeting of cancer

Acremonium phylogenetic overview and revision of Gliomastix, Sarocladium, and Trichothecium

AbstractOver 200 new sequences are generated for members of the genus Acremonium and related taxa including ribosomal small subunit sequences (SSU) for phylogenetic analysis and large subunit (LSU) sequences for phylogeny and DNA-based identification. Phylogenetic analysis reveals that within the Hypocreales, there are two major clusters containing multiple Acremonium species. One clade contains Acremonium sclerotigenum, the genus Emericellopsis, and the genus Geosmithia as prominent elements. The second clade contains the genera Gliomastix sensu stricto and Bionectria. In addition, there are numerous smaller clades plus two multi-species clades, one containing Acremonium strictum and the type species of the genus Sarocladium, and, as seen in the combined SSU/LSU analysis, one associated subclade containing Acremonium breve and related species plus Acremonium curvulum and related species. This sequence information allows the revision of three genera. Gliomastix is revived for five species, G. murorum, G. polychroma, G. tumulicola, G. roseogrisea, and G. masseei. Sarocladium is extended to include all members of the phylogenetically distinct A. strictum clade including the medically important A. kiliense and the protective maize endophyte A. zeae. Also included in Sarocladium are members of the phylogenetically delimited Acremonium bacillisporum clade, closely linked to the A. strictum clade. The genus Trichothecium is revised following the principles of unitary nomenclature based on the oldest valid anamorph or teleomorph name, and new combinations are made in Trichothecium for the tightly interrelated Acremonium crotocinigenum, Spicellum roseum, and teleomorph Leucosphaerina indica. Outside the Hypocreales, numerous Acremonium-like species fall into the Plectosphaerellaceae, and A. atrogriseum falls into the Cephalothecaceae

The Monocarboxylate Transporter Inhibitor α-Cyano-4-Hydroxycinnamic Acid Disrupts Rat Lung Branching

BACKGROUND/AIMS: The human embryo develops in a hypoxic environment. In this way, cells have to rely on the glycolytic pathway for energy supply, leading to an intracellular accumulation of monocarboxylates such as lactate and pyruvate. These acids have an important role in cell metabolism and their rapid transport across the plasma membrane is crucial for the maintenance of intracellular pH homeostasis. This transport is mediated by a family of transporters, designated by monocarboxylate transporters (MCTs), namely isoforms 1 and 4. MCT1/4 expression is regulated by the ancillary protein CD147.The general aim of this study was to characterize the expression pattern of MCT1/4, CD147 and the glucose transporter GLUT1 during human fetal lung development and elucidate the role of MCTs in lung development. METHODS: The expression pattern of MCT1/4 and GLUT1 was characterized by immunohistochemistry and fetal lung viability and branching were evaluated by exposing rat fetal lung explants to CHC, an inhibitor of MCT activity. RESULTS: Our findings show that all the biomarkers are differently expressed during fetal lung development and that CHC appears to have an inhibitory effect on lung branching and viability, in a dose dependent way. CONCLUSION: We provide evidence for the role of MCTs in embryo lung development, however to prove the dependence of MCT activity further studies are waranted.This work was supported by the Life and Health Sciences Research Institute, University of Minho, Portugal, and Fundacao para a Ciencia e Tecnologia (SFRH/BD/33503/2010 to S.G., SFRH/BD/87139/2012 to F.M.S. and SFRH/BD/51997/2012 to V.M.G.

Melanoma do intestino delgado: primário ou metastático? um caso clínico

Malignant melanoma often originated from melanocytes can occur wherever these cells are present. Most common locations are the skin, retina, anus and under the nail. Although rare, primary gastrointestinal tract melanoma has been reported, mostly from the oesophagus and anorectal region. In the small bowel represents 5% of primary neoplasms. We report a case of a 70 year old man, who presented with abdominal pain, weigh loss and anaemia. Based on the findings of CT, endoscopy and entheroscopy a preoperative diagnosis of a small bowel tumour was established. Was submitted to a multiple segmental enterectomy, the histopathological examination revealed a malignant melanoma. A thorough postoperative investigation did not reveal a primary lesion in the skin, oculus or any other location. Brain and pulmonary metastasis where diagnosed afterwards and he died three months after surgery. In a patient without any obvious primary tumour, with a gastrointestinal melanoma and without extraintestinal lesions we should rule out primary gastrointestinal melanoma. Keywords: Malignant melanoma, small bowel, gastrointestinal tract. O melanoma tem geralmente a sua origem em células da linha melanocítica, podendo ocorrer em todos os locais onde estas células estão presentes. Localiza-se mais frequentemente na pele, retina, ânus, leito ungueal e plexos coroideus. Embora muito raro, foi documentado melanoma primitivo do tracto gastrointestinal, sobretudo no esófago e região ano-rectal. No intestino delgado representa cerca de 5% das neoplasias primárias. Expõe-se o caso de um homem de 70 anos, que se apresentou com dor abdominal, emagrecimento e anemia. Com base na TAC, endoscopia e enteroscopia por cápsula estabeleceu-se o diagnóstico clínico pré-operatório de neoformação do intestino delgado. Foi submetido a enterectomia segmentar múltipla, o exame anatomo-patológico da peça excisada revelou tratar-se de melanoma. Perante este diagnóstico, o doente foi exaustivamente estudado, no sentido de excluir lesões prévias, ou não, na pele ou em outras localizações que justificassem a hipótese de metastização de melanoma no tracto gastrointestinal mas nada foi encontrado. Posteriormente foram-lhe diagnosticadas duas lesões expansivas cerebrais e múltiplas lesões pulmonares, vindo a falecer três meses após a cirurgia. Num doente sem tumor primário óbvio e com melanoma gastrointestinal, sem evidência de lesões extra-intestinais, coloca-se a hipótese diagnóstica de melanoma primário do tracto gastrointestinal. Palavras-chave: Melanoma, intestino delgado, tracto gastro-intestinal.

Damage evaluation during installation of geosynthetics used in asphalt pavements

Geosynthetics are commonly used as anti-reflective cracking systems in asphalt pavements. The rehabilitation design methods use the characteristics of as-received geosynthetics as inputs. However, these materials undergo physical damage during their installation due to mechanical and thermal loads which currently are not taken into account in the design processes. These loads can produce a reduction in geosynthetic strength and therefore, it is necessary to know the secant modulus after installation in order to improve the pavement design incorporating these materials. The secant modulus of a material indicates its initial stiffness. This paper describes an experimental study of damage due to installation of five different geosynthetics using three different procedures: (i) mechanical damage induced in the laboratory considering the action of aggregates, (ii) in situ mechanical and thermal damage due to actual installation in a test section, and (iii) a new mechanical and thermal damage experimental test developed with the aim of reproducing the real installation conditions. The main results of the study indicate that the obtained secant modulus of the tested geosynthetics reduced after applying the three damage procedures, and the loss of properties differed depending on the type and constitutive material and on the applied damage procedure.This investigation was supported by the research Project ‘Rehabilitation of roads and highways (REHABCAR)’ file number IPT-370000–2010–029, led by DRAGADOS (ACS Group), in collaboration with GEOCISA and ASFALTOS AUGUSTA among others. The project has been funded by the Ministry of Economy and Competitiveness (MINECO) within the National Plan for Scientific Research, Development and Innovation 2008–2011 (INNPACTO 2010) and the European Union under ERDF Funds (European Regional Development Fund)