Fabrication of surface plasmon resonators by nanoskiving single-crystalline gold microplates

This paper demonstrates the sectioning of chemically synthesized, single-crystalline microplates of gold with an ultramicrotome (nanoskiving) to produce single-crystalline nanowires; these nanowires act as low-loss surface plasmon resonators. This method produces collinearly aligned nanostructures with small, regular changes in dimension with each consecutive cross-section: a single microplate thus can produce a number of "quasi-copies" (delicately modulated variations) of a nanowire. The diamond knife cuts cleanly through microplates 35 mum in diameter and 100 nm thick without bending the resulting nanowire and cuts through the sharp edges of a crystal without deformation to generate nanoscale tips. This paper compares the influence of sharp tips and blunt tips on the resonator modes in these nanowires.     

Critical study of existing solutions for a penny-shaped interface crack, comparing with a new boundary element solution allowing for frictionless contact

A numerical study of the fundamental problem of a pressurized penny-shaped crack at the interface of two dissimilar half spaces is carried out allowing for the possibility of frictionless contact between crack faces. A new, highly accurate axi-symmetric formulation of the boundary element method (BEM) for the solution of elastic contact problems is employed. The correctness and accuracy of available predictions of different kinds for several key characteristics of the solution of this problem are checked. First, comparison of the BEM results for the near-tip contact length shows a very good agreement with some existing predictions. Second, the global solution obtained by BEM is compared with existing asymptotic solutions, obtained with both the open and the frictionless contact models. BEM results show that at the closest neighborhood to the crack tip the global solution of the problem is governed by the first term of the asymptotic solution of the frictionless contact model (up to a distance of the order of a fraction of the near-tip contact length). After a small transition region, in an adjacent surrounding zone whose extent is almost independent of the near-tip contact length, the global solution of the problem is governed by the first term of the asymptotic solution of the open model. As a result of the comparison presented, the regions in which the classical fracture parameters, stress intensity factor (SIF) and energy release rate, can be accurately obtained from the global numerical solution of a crack of this kind have been determined. Third, BEM results and previous estimations show certain discrepancies with a recently published closed form solution of the near-tip contact length and the mode II SIF of the frictionless contact model. A new closed form expression of this mode II SIF, derived from the asymptotic solution of the open model, is proposed in this paper.     

Biomarkers for Ehlers-Danlos Syndromes: There Is a Role?

Ehlers-Danlos syndromes (EDS) are an inherited heterogeneous group of connective tissue disorders characterized by an abnormal collagen synthesis affecting skin, ligaments, joints, blood vessels, and other organs. It is one of the oldest known causes of bruising and bleeding, and it was described first by Hippocrates in 400 BC. In the last years, multiple gene variants involved in the pathogenesis of specific EDS subtypes have been identified; moreover, new clinical diagnostic criteria have been established. New classification models have also been studied in order to differentiate overlapping conditions. Moreover, EDS shares many characteristics with other similar disorders. Although distinguishing between these seemingly identical conditions is difficult, it is essential in ensuring proper patient care. Currently, there are many genetic and molecular studies underway to clarify the etiology of some variants of EDS. However, the genetic basis of the hypermobile type of EDS (hEDS) is still unknown. In this review, we focused on the study of two of the most common forms of EDS—classic and hypermobile—by trying to identify possible biomarkers that could be of great help to confirm patients’ diagnosis and their follow up.     

Waste glass as a supplementary cementitious material in concrete – Critical review of treatment methods

Concrete is the most widely used construction material and, for the most part, is produced using non-renewable natural resources and energy intensive processes which emit greenhouse gasses. There exists an opportunity to improve the sustainability of this industry by further exploring the use of alternative materials. As an aggregate, glass bottle waste has faced specific challenges including bond, ASR gel production, and strength degradation of the concrete. This paper reviews the literature pertaining to incorporating waste glass into concrete as a supplementary cementing material. Pozzolanic properties of waste glass as an SCM and ASR are related to particle size and percent addition. Lithium additives control ASR expansion; however, the mechanism of this control has yet to be defined.     

The role of weathering on fly ash charge distribution during triboelectrostatic beneficiation

Triboelectrostatic beneficiation of coal combustion fly ashes with high-unburned carbon contents can produce low-carbon ash products having value as mineral admixtures and meeting technical requirements for replacing cement in concrete. This capability is a result of establishing bipolar charge on mineral ash versus carbon particles where, typically, unburned carbon attains positive surface charge and ash attains negative surface charge under the tribocharging conditions employed in triboelectrostatic technologies. However, long-term exposure of fly ash to weathering conditions, such as moisture or high humidity, before beneficiation is known to dramatically diminish carbon-ash separation efficiencies. Although experimentation has shown that water soluble surface species can be redistributed on fly ash particles after exposure to moisture, which could affect the extent of charging and polarities, measurement of the actual amount of charge and polarity on particles after weathering exposure versus after removal of surface moisture has not been accomplished. Hence, a new experimental methodology was developed and applied to measure charge distributions on tribocharged ash and carbon particles in a fly ash that had been exposed to weathering conditions for 6 months before and after removal of the surface moisture. Weathered ash particles were found to have an average zero charge, whereas carbon particles attained an average negative charge, opposite of the normal polarity for carbon. Although the extent of uncharged particles decreased and ash particles attained an average negative charge after drying, carbon particles attained only an average zero charge. These changes were reflected in very small increases in carbon-ash separation efficiency, in contrast to previous beneficiation tests in which fly ash drying led to significant increases in carbon-ash separation efficiency. It is suggested that removal of surface moisture in the absence of other processes like surface ion redistribution would beneficially impact carbon-ash triboelectrostatic beneficiation.     

Application of calorimetric measurements for biokinetic characterisation of nitrifying population in activated sludge

A preliminary investigation is described on the application of calorimetry as a sensitive technique to evaluate nitrifying activity in activated sludge. Calorimetric profiles (thermograms) related to heat dissipation due to biological nitrification reactions (ammonia or nitrite consumption) have been interpreted. Correlations between calorimetric data and the main process variables, i.e. ammonia and nitrite concentration and oxygen uptake, have been verified, and confirm the potential of calorimetry to investigate, monitor and control even weakly exothermic biological processes like autotrophic nitrification. Heat yields (Y(Q/i)) for ammonia, nitrite, and oxygen, defined as the heat released per unit amount of converted reactant, have been separately evaluated. Moreover, calorimetric experiments on activated sludge from a full-scale nitrogen removal wastewater treatment plant have been carried out and kinetic parameters for both ammonia and nitrite oxidising bacteria have been estimated.     

5′‐Trityl‐Substituted Thymidine Derivatives as a Novel Class of Antileishmanial Agents: Leishmania infantum EndoG as a Potential Target

Two series of 5′‐triphenylmethyl (trityl)‐substituted thymidine derivatives were synthesized and tested against Leishmania infantum axenic promastigotes and amastigotes. Several of these compounds show significant antileishmanial activity, with IC₅₀ values in the low micromolar range. Among these, 3′‐O‐(isoleucylisoleucyl)‐5′‐O‐(3,3,3‐triphenylpropanoyl)thymidine displays particularly good activity against intracellular amastigotes. Assays performed to characterize the nature of parasite cell death in the presence of the tritylthymidines indicated significant alterations in mitochondrial transmembrane potential, an increase in superoxide concentrations, and also significant decreases in DNA degradation during the cell death process. Results point to the mitochondrial nuclease LiEndoG as a target for the action of this family of compounds.     

Novel Glass‐Ceramic Composition as Sealant for SOFCs

This work deals with the design, the characterization, and testing of a novel glass‐ceramic to be used as sealant for planar solid oxide fuel cells and its compatibility with Mn_1.5Co_1.5O₄‐coated Crofer22APU. Thermal, sintering, and crystallization behavior and thermo mechanical properties of the sealant are reviewed and discussed, indicating therefore that these compositions can be deposited at 850°C and provide an excellent compatibility with both the Mn_1.5Co_1.5O₄‐coated Crofer22APU and the anode‐supported electrolyte. In particular, Mn_1.5Co_1.5O₄‐coated Crofer22APU/sealant/anode‐supported‐electrolyte joined samples have been submitted to thermal tests (in air atmosphere) from RT to 800°C (SOFC operating temperature) up to 500 h. No interactions, cracks formation, or failure were observed at the Mn_1.5Co_1.5O₄‐coated Crofer22APU/sealant interface and between the glass‐ceramic and the anode‐supported‐electrolyte after 500 h of thermal tests in air atmosphere.