Lateral phase separation of confined membranes

We consider membranes interacting via short, intermediate and long stickers. The effects of the intermediate stickers on the lateral phase separation of the membranes are studied via mean-field approximation. The critical potential depth of the stickers increases in the presence of the intermediate sticker. The lateral phase separation of the membrane thus suppressed by the intermediate stickers. Considering membranes interacting with short and long stickers, the effect of confinement on the phase behavior of the membranes is also investigated analytically

Adhesion-induced lateral phase separation of multi-component membranes: the effect of repellers and confinement

We present a theoretical study for adhesion-induced lateral phase separation for a membrane with short stickers, long stickers and repellers confined between two hard walls. The effects of confinement and repellers on lateral phase separation are investigated. We find that the critical potential depth of the stickers for lateral phase separation increases as the distance between the hard walls decreases. This suggests confinement-induced or force-induced mixing of stickers. We also find that stiff repellers tend to enhance, while soft repellers tend to suppress adhesion-induced lateral phase separation

Miocene faunal remains from the Burji-Soyama area, Amaro Horst, southern sector of the main Ethiopian Rift

The Palaeoanthropological Inventory of Ethiopia is dedicated to the discovery and documentation of palaeoanthropologically significant study areas in the Main Ethiopian Rift and Afar Depression. Fieldwork in the area at the southern end of the Amaro Horst during the 1989 field season was focused on a fossiliferous sedimentary succession with intercalated volcanic horizons. Potassium-argon dating sets a minimum age of 11.1 my for sediments bearing vertebrate remains. The partial skeleton of a fossil proboscidean recovered at Burji is described, illustrated and assessed comparatively. The remains are those of a primitive species of choerolophodont mastodon. Biochronological considerations place this specimen in the time range of 15-17 my. The presence of fossiliferous sediments in the Burji area suggest that a rift-related basin had developed in this part of Ethiopia by Middle or Early Miocene times.National Geographic Society 4134-89; National Science Foundation Anthropology Program: BSN 88-19735; Centre for Research and Conservation of the Cultural Heritage, Ethiopian Ministry of Culture and Sports Affair

Segregation of receptor-ligand complexes in cell adhesion zones: Phase diagrams and role of thermal membrane roughness

The adhesion zone of immune cells, the 'immunological synapse', exhibits characteristic domains of receptor-ligand complexes. The domain formation is likely caused by a length difference of the receptor-ligand complexes, and has been investigated in experiments in which T cells adhere to supported membranes with anchored ligands. For supported membranes with two types of anchored ligands, MHCp and ICAM1, that bind to the receptors TCR and LFA1 in the cell membrane, the coexistence of domains of TCR-MHCp and LFA1-ICAM1 complexes in the cell adhesion zone has been observed for a wide range of ligand concentrations and affinities. For supported membranes with long and short ligands that bind to the same cell receptor CD2, in contrast, domain coexistence has been observed for a rather narrow ratio of ligand concentrations. In this article, we determine detailed phase diagrams for cells adhering to supported membranes with a statistical-physical model of cell adhesion. We find a characteristic difference between the adhesion scenarios in which two types of ligands in a supported membrane bind (i) to the same cell receptor or (ii) to two different cell receptors, which helps to explain the experimental observations. Our phase diagrams fully include thermal shape fluctuations of the cell membranes on nanometer scales, which lead to a critical point for the domain formation and to a cooperative binding of the receptors and ligands.Comment: 23 pages, 6 figure

Work extremum principle: Structure and function of quantum heat engines

We consider a class of quantum heat engines consisting of two subsystems interacting via a unitary transformation and coupled to two separate baths at different temperatures $T_h > T_c$. The purpose of the engine is to extract work due to the temperature difference. Its dynamics is not restricted to the near equilibrium regime. The engine structure is determined by maximizing the extracted work under various constraints. When this maximization is carried out at finite power, the engine dynamics is described by well-defined temperatures and satisfies the local version of the second law. In addition, its efficiency is bounded from below by the Curzon-Ahlborn value $1-\sqrt{T_c/T_h}$ and from above by the Carnot value $1-(T_c/T_h)$. The latter is reached|at finite power|for a macroscopic engine, while the former is achieved in the equilibrium limit $T_h\to T_c$. When the work is maximized at a zero power, even a small (few-level) engine extracts work right at the Carnot efficiency.Comment: 16 pages, 5 figure

Onsager coefficients of a Brownian Carnot cycle

We study a Brownian Carnot cycle introduced by T. Schmiedl and U. Seifert [Europhys. Lett. \textbf{81}, 20003 (2008)] from a viewpoint of the linear irreversible thermodynamics. By considering the entropy production rate of this cycle, we can determine thermodynamic forces and fluxes of the cycle and calculate the Onsager coefficients for general protocols, that is, arbitrary schedules to change the potential confining the Brownian particle. We show that these Onsager coefficients contain the information of the protocol shape and they satisfy the tight-coupling condition irrespective of whatever protocol shape we choose. These properties may give an explanation why the Curzon-Ahlborn efficiency often appears in the finite-time heat engines

Seroprevalence of contagious caprine pleuropneumonia in Borana and Guji lowlands, Southern Ethiopia

A multistage cross sectional serological study and questionnaire survey were conducted on contagious caprine pleuropneumonia in selected districts of Borana and Guji lowlands, Southern Ethiopia, to determine the prevalence of the disease and identify risk factors associated with the occurrence of the disease. A total of 900 sera samples were collected and tested using Complement Fixation Test (CFT). Questionnaire surveys were conducted with 69 randomly selected households. Out of the 900 goat sera samples tested, 119 (13.2%) were seropositive for CCPP, giving an overall seroprevalence of 13.2 % (95% CI=11.0%-15.4%) in the study areas. A seroprevalence of 18.3% (95% CI=14.3%-22.7%), 11.7% (95% CI=8%-15.2%) and 9.7% (95% CI=6.3%-12.6%) were recorded in Liban, Teltale and Moyale districts respectively. The seroprevalence recorded in Liban district was significantly different from that of Moyale district (

Direct observation of active material concentration gradients and crystallinity breakdown in LiFePO4 electrodes during charge/discharge cycling of lithium batteries

The phase changes that occur during discharge of an electrode comprised of LiFePO4, carbon, and PTFE binder have been studied in lithium half cells by using X-ray diffraction measurements in reflection geometry. Differences in the state of charge between the front and the back of LiFePO4 electrodes have been visualized. By modifying the X-ray incident angle the depth of penetration of the X-ray beam into the electrode was altered, allowing for the examination of any concentration gradients that were present within the electrode. At high rates of discharge the electrode side facing the current collector underwent limited lithium insertion while the electrode as a whole underwent greater than 50% of discharge. This behavior is consistent with depletion at high rate of the lithium content of the electrolyte contained in the electrode pores. Increases in the diffraction peak widths indicated a breakdown of crystallinity within the active material during cycling even during the relatively short duration of these experiments, which can also be linked to cycling at high rate

Climate Change, Foodborne Pathogens, and Illness in Higher Income Countries

Purpose of review: We present a review of the likely consequences of climate change for foodborne pathogens and associated human illness in higher income countries. Recent findings: The relationships between climate and food are complex and hence the impacts of climate change uncertain. This makes it difficult to know which foodborne pathogens will be most affected, what the specific effects will be, and on what timescales changes might occur. Hence, a focus upon current capacity and adaptation potential against foodborne pathogens is essential. We highlight a number of developments that may enhance preparedness for climate change. These include: • Adoption of novel surveillance methods, such as syndromic methods, to speed up detection and increase the fidelity of intervention in foodborne outbreaks • Genotype based approaches to surveillance of food pathogens to enhance spatio-temporal resolution in tracing and tracking of illness • Ever increasing integration of plant, animal and human surveillance systems, one-health, to maximize potential for identifying threats • Increased commitment to cross-border (global) information initiatives (including big data) • Improved clarity regarding the governance of complex societal issues such as the conflict between food safety and food waste • Strong user centric (social) communications strategies to engage diverse stakeholder groups Summary: The impact of climate change upon foodborne pathogens and associated illness is uncertain. This emphasises the need to enhance current capacity and adaptation potential against foodborne illness. A range of developments are explored in this paper to enhance preparedness

Survival of hospitalised COVID-19 patients in Hawassa, Ethiopia: a cohort study

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