Dynamics of a molecular glass former: Energy landscapes for diffusion in ortho-terphenyl.

Relaxation times and transport processes of many glass-forming supercooled liquids exhibit a super-Arrhenius temperature dependence. We examine this phenomenon by computer simulation of the Lewis-Wahnström model for ortho-terphenyl. We propose a microscopic definition for a single-molecule cage-breaking transition and show that, when correlation behaviour is taken into account, these rearrangements are sufficient to reproduce the correct translational diffusion constants over an intermediate temperature range in the supercooled regime. We show that super-Arrhenius behaviour can be attributed to increasing negative correlation in particle movement at lower temperatures and relate this to the cage-breaking description. Finally, we sample the potential energy landscape of the model and show that it displays hierarchical ordering. Substructures in the landscape, which may correspond to metabasins, have boundaries defined by cage-breaking transitions. The cage-breaking formulation provides a direct link between the potential energy landscape and macroscopic diffusion behaviour.This work was supported by the University of Cambridge through a CHSS studentship to S.P.N., and by the European Research Council.This is the author accepted manuscript. The final version is available at http://dx.doi.org/10.1063/1.4954324

Effects of random pinning on the potential energy landscape of a supercooled liquid.

We use energy landscape methods to investigate the response of a supercooled liquid to random pinning. We classify the structural similarity of different energy minima using a measure of overlap. This analysis reveals a correspondence between distinct particle packings (which are characterised via the overlap) and funnels on the energy landscape (which are characterised via disconnectivity graphs). As the number of pinned particles is increased, we find a crossover from glassy behavior at low pinning to a structure-seeking landscape at high pinning, in which all thermally accessible minima are structurally similar. We discuss the consequences of these results for theories of randomly pinned liquids. We also investigate how the energy landscape depends on the fraction of pinned particles, including the degree of frustration and the evolution of distinct packings as the number of pinned particles is reduced.epsr

Shotgun Mass Spectrometry Workflow Combining IEF and LC-MALDI-TOF/TOF

We present a high throughput shotgun mass spectrometry workflow using a bidimensional peptide fractionation procedure consisting of isoelectric focusing and RP-HPLC prior to mass spectrometric analysis, with the aim of optimizing peptide separation and protein identification. As part of the workflow we used the ‘Isotope-Coded Protein Labeling’ (ICPL) method for accurate relative quantitation of protein expression. Such workflow was successfully applied to a comparative proteome analysis of schizophrenia versus healthy control brain tissues and can be an alternative to proteome researches

On the origin of the marine zinc–silicon correlation

The close linear correlation between the distributions of dissolved zinc (Zn) and silicon (Si) in seawater has puzzled chemical oceanographers since its discovery almost forty years ago, due to the apparent lack of a mechanism for coupling these two nutrient elements. Recent research has shown that such a correlation can be produced in an ocean model without any explicit coupling between Zn and Si, via the export of Zn-rich biogenic particles in the Southern Ocean, consistent with the observation of elevated Zn quotas in Southern Ocean diatoms. Here, we investigate the physical and biological mechanisms by which Southern Ocean uptake and export control the large-scale marine Zn distribution, using suites of sensitivity simulations in an ocean general circulation model (OGCM) and a box-model ensemble. These simulations focus on the sensitivity of the Zn distribution to the stoichiometry of Zn uptake relative to phosphate (PO4), drawing directly on observations in culture. Our analysis reveals that OGCM model variants that produce a well-defined step between relatively constant, high Zn:PO4 uptake ratios in the Southern Ocean and low Zn:PO4 ratios at lower latitudes fare best in reproducing the marine Zn–Si correlation at both the global and the regional Southern Ocean scale, suggesting the presence of distinct Zn-biogeochemical regimes in the high- and low-latitude oceans that may relate to differences in physiology, ecology or (micro-)nutrient status. Furthermore, a study of the systematics of both the box model and the OGCM reveals that regional Southern Ocean Zn uptake exerts control over the global Zn distribution via its modulation of the biogeochemical characteristics of the surface Southern Ocean. Specifically, model variants with elevated Southern Ocean Zn:PO4 uptake ratios produce near-complete Zn depletion in the Si-poor surface Subantarctic Zone, where upper-ocean water masses with key roles in the global oceanic circulation are formed. By setting the main preformed covariation trend within the ocean interior, the subduction of these Zn- and Si-poor water masses produces a close correlation between the Zn and Si distributions that is barely altered by their differential remineralisation during low-latitude cycling. We speculate that analogous processes in the high-latitude oceans may operate for other trace metal micronutrients as well, splitting the ocean into two fundamentally different biogeochemical, and thus biogeographic, regimes

E AGORA, BRECHT?

O objetivo deste artigo é analisar a intertextualidade entre a poesia de Bertold Brecht e Carlos Drummond de Andrade, sob a perspectiva da Segunda Guerra Mundial. A poesia alemã de Bertold Brecht ainda é pouco traduzida no Brasil. O autor tem vasta obra e inúmeros poemas reunidos no livro Die Gedichte von Bertold Brecht, onde retrata a dor, o sofrimento e o inconformismo declaradamente esquerdista perante o crescente nazismo na Alemanha no entre guerras. Já Drummond tem sua obra amplamente lida e apreciada. Os poemas que escolhi para esta análise são do livro A Rosa do Povo – publicado em 1945 – e considerado pela crítica como um dos mais poéticos e políticos. Busquei fundamentar a minha pesquisa em Hannah Arendt, John Willett, Erich Hobsbawm, Alfredo Bosi e Affonso Romano de Sant’Anna, entre outros.PALAVRAS CHAVE: Bertold Brecht. Carlos Drummond de Andrade. Segunda Guerra Mundial. Utopia. Abstract O objetivo deste artigo é analisar a intertextualidade entre a poesia de Bertold Brecht e Carlos Drummond de Andrade, sob a perspectiva da Segunda Guerra Mundial. A poesia alemã de Bertold Brecht ainda é pouco traduzida no Brasil. O autor tem vasta obra e inúmeros poemas reunidos no livro Die Gedichte von Bertold Brecht, onde retrata a dor, o sofrimento e o inconformismo declaradamente esquerdista perante o crescente nazismo na Alemanha no entre guerras. Já Drummond tem sua obra amplamente lida e apreciada. Os poemas que escolhi para esta análise são do livro A Rosa do Povo – publicado em 1945 – e considerado pela crítica como um dos mais poéticos e políticos. Busquei fundamentar a minha pesquisa em Hannah Arendt, John Willett, Erich Hobsbawm, Alfredo Bosi e Affonso Romano de Sant’Anna, entre outros.KEYWORDS: Bertold Brecht. Carlos Drummond de Andrade. Second World War. Utopia DOI: https://doi.org/10.47295/mren.v2i1.396

Diabetic ketoacidosis complicated by the use of ecstasy: a case report

<p>Abstract</p> <p>Introduction</p> <p>Ecstasy (3,4-methylenedioxymethamphetamin), a hallucinogenic amphetamine, is often used by young people, especially at 'raves'. This illicit drug can cause many metabolic changes and its use, when associated with prolonged exercise, may exacerbate ketoacidosis in type 1 diabetic patients.</p> <p>Case presentation</p> <p>This is a case of ketoacidosis complicated by the use of ecstasy in a 19-year-old insulin-dependent diabetic Caucasian woman.</p> <p>Conclusion</p> <p>The use of ecstasy may trigger diabetic ketoacidosis in patients with a preexisting metabolic disorder</p

Defining and quantifying frustration in the energy landscape: Applications to atomic and molecular clusters, biomolecules, jammed and glassy systems

The emergence of observable properties from the organisation of the underlying potential energy landscape is analysed, spanning a full range of complexity from self-organising to glassy and jammed systems. The examples include atomic and molecular clusters, a β-barrel protein, the GNNQQNY peptide dimer, and models of condensed matter that exhibit structural glass formation and jamming. We have considered measures based on several different properties, namely, the Shannon entropy, an equilibrium thermodynamic measure that uses a sample of local minima, and indices that require additional information about the connections between local minima in the form of transition states. A frustration index is defined that correlates directly with key properties that distinguish relaxation behaviour within this diverse set. The index uses the ratio of the energy barrier to the energy difference with reference to the global minimum. The contributions for each local minimum are weighted by the equilibrium occupation probabilities. Hence we obtain fundamental insight into the connections and distinctions between systems that cover the continuum from efficient structure-seekers to landscapes that exhibit broken ergodicity and rare event dynamics.We acknowledge the Engineering and Physical Sciences Research Council, UK (EPSRC) for funding under Programme Grant No. EP/I001352/1 and the European Research Council (ERC)

Fever induction pathways: evidence from responses to systemic or local cytokine formation

Abstract The immune and central nervous systems are functionally connected and interacting. The concept that the immune signaling to the brain which induces fever during infection and inflammation is mediated by circulating cytokines has been traditionally accepted. Administration of bacterial lipopolysaccharide (LPS) induces the appearance of a sotermed cytokine cascade in the circulation more or less concomitantly to the developing febrile response. Also, LPS-like fever can be induced by systemic administration of key cytokines (IL-1ß, TNF-a, and others). However, anti-cytokine strategies against IL-1ß or TNFa along with systemic injections of LPS frequently lead to attenuation of the later stages of the febrile response but not of the initial phase of fever, indicating that cytokines are rather involved in the maintenance than in the early induction of fever. Within the last years experimental evidence has accumulated indicating the existence of neural transport pathways of immune signals to the brain. Because subdiaphragmatic vagotomy prevents or attenuates fever in response to intraperitoneal or intravenous injections of LPS, a role for vagal afferent nerve fibers in fever induction has been proposed. Also other sensory nerves may participate in the manifestation of febrile responses under certain experimental conditions. Thus, injection of a small dose of LPS into an artificial subcutaneous chamber results in fever and formation of cytokines within the inflamed tissue around the site of injection. This febrile response can be blocked in part by injection of a local anesthetic into the subcutaneous chamber, indicating a participation of cutaneous afferent nerve signals in the manifestation of fever in this model. In conclusion, humoral signals and an inflammatory stimulation of afferent sensory nerves can participate in the generation and maintenance of a febrile response. Key words Humoral signals and fever: the relation between circulating cytokines and the febrile response After a challenge with an infectious or inflammatory stimulus somewhere at the periphery of the body a number of responses are generated within the CNS. These brainmediated signs of illness include changes in neuroendocrine activities including activation of the hypothalamic-pituitary-adrenal (HPA) axis, anorexia and adipsia, changes i

CETACEAN RECORDS ALONG SAO PAULO STATE COAST, SOUTHEASTERN BRAZIL

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)The Sao Paulo state (SP) coast (23 degrees 18'S, 44 degrees 42'W; 25 degrees 14'S, 48 degrees 01'W) is of approximately 600 km in length, bordering the Western Atlantic Ocean, in southeastern Brazil. Cetacean sightings and strandings have long been observed throughout this area. Scattered data from scientific publications, skeletal remains in museums, photographs and articles from newspaper files, universities and aquaria have been organised and updated since 1993. Field investigations on strandings and sightings have also been conducted. A total of 29 cetacean species have been recorded, including 7 baleen whales (Mysticeti) and 22 toothed whales (Odontoceti), as follows: Balaenoptera physalus, B. borealis, B. edeni, B. acutorostrata, B. bonaerensis, Megaptera novaeangliae, Eubalaena australis, Physeter macrocephalus, Kogia breviceps, K. sima, Berardius arnuxii, Mesoplodon europaeus, M. mirus, Ziphius cavirostris, Orcinus orca, Feresa attenuata, Globicephala melas, G. macrorhynchus, Pseudorca crassidens, Delphinus capensis, Lagenodelphis hosei, Steno bredanensis, Tursiops truncatus, Stenella frontalis, S. longirostris, S. coeruleoalba, Lissodelphis peronii, Sotalia guianensis and Pontoporia blainvillei. Several species have been observed only once and include strays from their areas of common distribution, as well as species with known preferences for offshore distribution. Others, such as P. blainvillei and S. guianensis, are common coastal dwellers year-round. Z. cavirostris, P. crassidens and L. hosei are reported for the first time on the SP coast.582123142Cetacean International SocietyWhale & Dolphin Conservation SocietyWWF-Fundo Mundial para a NaturezaEarthwatch InstitutePetrobrasCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq