The influence of charge on the multiple thermal transitions observed in xanthan

Helix-coil transitions in xanthans occur at lower temperatures when the pyruvate group is charged, destabilising the polymer chains. Increasing salt content increases the transition temperature by reducing the effective charge on the pyruvate. A simple equivalent mass action model predicts how transition temperatures change as a function of salt concentration. The functional form of the change in transition temperature (1/T) versus natural log (salt concentration) is approximately linear and similar to more traditional polyelectrolyte theories. Transition temperatures in xanthans containing nominally homogeneous pyruvate contents show biphasic transitions, this is because the phases contain different pyruvate levels, however the transitions approach one another in temperature and eventually merge as salt content is increased. It is proposed that pyruvate groups, despite being present at a lower concentration relative to glucuronic acid, dominate the charge interactions due to their location on the outside of the helices

Performance of Timber, Masonry and Earth houses in the Christchurch earthquakes New Zealand September 2010 and February 2011

Two earthquakes struck close to Christchurch city in New Zealand generating high level ground excitations that caused severe geotechnical effects and widespread structural damage. This paper focuses on damage to timber and masonry that resulted from the geotechnical effects experienced including liquefaction, lateral spreading, rock fall, horizontal and vertical ground accelerations. Light timber framed construction performed well for life safety but there were a large number seriously damaged, heavy masonry caused significant problems when inadequately reinforced. Changes to the construction standards are needed to improve foundation requirements and lateral wall bracing. Earth building damage to modern houses is discussed in reference to the New Zealand Earth Building Standards, and particularly the non-specific design clauses which specify a consistent reinforcing approach. Double skin pressed earth brick and earth brick veneers performed badly and will be excluded in a future revision. Historic unreinforced earth buildings suffered serious damage that was typical for the level of shakin

Recent progress in biohydrometallurgy and microbial characterisation

Since the discovery of microbiological metal dissolution, numerous biohydrometallurgical approaches have been developed to use microbially assisted aqueous extractive metallurgy for the recovery of metals from ores, concentrates, and recycled or residual materials. Biohydrometallurgy has helped to alleviate the challenges related to continually declining ore grades by transforming uneconomic ore resources to reserves. Engineering techniques used for biohydrometallurgy span from above ground reactor, vat, pond, heap and dump leaching to underground in situ leaching. Traditionally biohydrometallurgy has been applied to the bioleaching of base metals and uranium from sulfides and biooxidation of sulfidic refractory gold ores and concentrates before cyanidation. More recently the interest in using bioleaching for oxide ore and waste processing, as well as extracting other commodities such as rare earth elements has been growing. Bioprospecting, adaptation, engineering and storing of microorganisms has increased the availability of suitable biocatalysts for biohydrometallurgical applications. Moreover, the advancement of microbial characterisation methods has increased the understanding of microbial communities and their capabilities in the processes. This paper reviews recent progress in biohydrometallurgy and microbial characterisatio

Scale-dependent metric and causal structures in Quantum Einstein Gravity

Within the asymptotic safety scenario for gravity various conceptual issues related to the scale dependence of the metric are analyzed. The running effective field equations implied by the effective average action of Quantum Einstein Gravity (QEG) and the resulting families of resolution dependent metrics are discussed. The status of scale dependent vs. scale independent diffeomorphisms is clarified, and the difference between isometries implemented by scale dependent and independent Killing vectors is explained. A concept of scale dependent causality is proposed and illustrated by various simple examples. The possibility of assigning an "intrinsic length" to objects in a QEG spacetime is also discussed.Comment: 52 page

(n+1)(n+1)-Dimensional Lorentzian Wormholes in an Expanding Cosmological Background

We discuss $(n+1)$-dimensional dynamical wormholes in an evolving cosmological background with a throat expanding with time. These solutions are examined in the general relativity framework. A linear relation between diagonal elements of an anisotropic energy-momentum tensor is used to obtain the solutions. The energy-momentum tensor elements approach the vacuum case when we are far from the central object for one class of solutions. Finally, we discuss the energy-momentum tensor which supports this geometry, taking into account the energy conditions .Comment: 12 pages, 14 figures, references added, to appear in Astophysics and Space Scienc

New Lump-like Structures in Scalar-field Models

In this work we investigate lump-like solutions in models described by a single real scalar field. We start considering non-topological solutions with the usual lump-like form, and then we study other models, where the bell-shape profile may have varying amplitude and width, or develop a flat plateau at its top, or even induce a lump on top of another lump. We suggest possible applications where these exotic solutions might be used in several distinct branches of physics.Comment: REvTex4, twocolumn, 10 pages, 9 figures; new reference added, to appear in EPJ

Entrapment of a Network of Domain Walls

We explore the idea of a network of defects to live inside a domain wall in models of three real scalar fields, engendering the Z_2 x Z_3 symmetry. The field that governs the Z_2 symmetry generates a domain wall, and entraps the hexagonal network formed by the three-junctions of the model of two scalar fields that describes the remaining Z_3 symmetry. If the host domain wall bends to the spherical form, in the thin wall approximation there may appear non-topological structures hosting networks that accept diverse patterns. If Z_3 is also broken, the model may generate a buckyball containing sixty junctions, a fullerene-like structure. Applications to cosmology are outlined.Comment: Revtex, 4 pages, 2 ps figures; version to appear in Phys. Rev. D, Rapid Communicatio

Discarded livers tested by normothermic machine perfusion in the VITTAL trial:Secondary end points and 5-year outcomes

Normothermic machine perfusion (NMP) enables pretransplant assessment of high-risk donor livers. The VITTAL trial demonstrated that 71% of the currently discarded organs could be transplanted with 100% 90-day patient and graft survivals. Here, we report secondary end points and 5-year outcomes of this prospective, open-label, phase 2 adaptive single-arm study. The patient and graft survivals at 60 months were 82% and 72%, respectively. Four patients lost their graft due to nonanastomotic biliary strictures, one caused by hepatic artery thrombosis in a liver donated following brain death, and 3 in elderly livers donated after circulatory death (DCD), which all clinically manifested within 6 months after transplantation. There were no late graft losses for other reasons. All the 4 patients who died during the study follow-up had functioning grafts. Nonanastomotic biliary strictures developed in donated after circulatory death livers that failed to produce bile with pH &gt;7.65 and bicarbonate levels &gt;25 mmol/L. Histological assessment in these livers revealed high bile duct injury scores characterized by arterial medial necrosis. The quality of life at 6 months significantly improved in all but 4 patients suffering from nonanastomotic biliary strictures. This first report of long-term outcomes of high-risk livers assessed by normothermic machine perfusion demonstrated excellent 5-year survival without adverse effects in all organs functioning beyond 1 year (ClinicalTrials.gov number NCT02740608).</p

Manual / Issue 13 / Storage

Manual, a journal about art and its making. Storage. Manual 13 opens with an introduction by Fred Wilson, who confides, “You can look at all the opulence on display in a museum and begin to understand that something nefarious might be behind it. Storage, for me, is where the action is.” Museums usually make choices for viewers, their curators presenting what they think most important within a category. They can be so good at doing this that visitors sometimes don’t realize there’s anything else to see: they don’t realize the nature of the decisions behind an exhibition, and they accept that the elites have made a judgment about which shoe is the shoe to see. Visitors can learn about what’s great, but they don’t necessarily consider the process of discernment. –– Fred Wilson The RISD Museum’s thirteenth issue of Manual unpacks the idea and reality of storage—objects museums don’t put on view, works made as containers of various sorts, and more metaphorical considerations about how meanings and narratives are stored. This issue serves as a companion to the Raid the Icebox Now series of exhibitions on view at the RISD Museum through November 2020, in which nine contemporary artists and design collectives use the museum and its collections as a site for critical creative production and presentation. Raid the Icebox Now marks the 50th anniversary of Raid the Icebox 1 with Andy Warhol, held in 1970 at the RISD Museum. Softcover, 120 pages. Published Fall/Winter 2019 by the RISD Museum. Manual 13 (Storage) contributors include: Christina Alderman, Issac M. Alderman, A.H. Jerriod Avant, Hannah Carlson, Wai Yee Chiong, John Dunnigan, Maria Morris Hambourg, David Hartt, Elaine Tyler May, Claire McCardell, Denise Murrell, Ingrid Schaffner, Holly Shaffer, Tanya Sheehan, John W. Smith, Mimi Smith, Sassan Tabatabai, Allen Wexler, and Fred Wilson.https://digitalcommons.risd.edu/risdmuseum_journals/1039/thumbnail.jp