Increase of load‐carrying capacity of masonry with textile reinforced rendering / Erhöhung der Tragfähigkeit von Mauerwerk mit textilbewehrtem Putz

Contemporary externally bonded structural upgrading schemes for masonry structures employ Fiber Reinforced Polymer (FRP) systems (a technique that was extended from concrete to masonry structures) and technical textiles (structural fiber grids) embedded in inorganic matrices. The latter account for a multitude of systems depending on the type of grid – fiber material, bundle treatment (dry, coated or even impregnated), grid geometry, manufacturing method etc. – and matrix – binder (e.g. cement or lime), rheology etc. – resulting in the derivation of many different acronyms (FRCM, TRM, CMG, IMG or other – see for definitions below). The mechanical behavior of such systems and their interaction with different substrates may vary significantly (e.g. dry vs. impregnated fiber grids embedded in mortars). This paper aims to summarize all reported efforts to increase the load‐carrying and/or deformation capacity of unreinforced masonry walls against in‐plane loading and second‐order phenomena (eccentric compressive loading).     

Integrated biological and chemical analysis of organochlorine compound pollution and of its biological effects in a riverine system downstream the discharge point

Pollution in riverine systems, along with its biological effects, may propagate downstream even at considerable distances. We analyzed the organochlorine compound (OC) pollution in a section of the low Ebro River (Northeast Spain) downstream a long-operating chlor-alkali plant. Maximal levels of OCs and of their associated dioxin-like biological activity occurred in residue samples from the plant, and persisted in river sediments some 40 km downstream (Xerta site). Biological analysis at multiple organization levels in local carp (Cyprinus carpio, EROD, Cyp1A mRNA expression in the liver, hepatosomatic index, condition factor, and micronuclei index in peripheral blood) showed a similar pattern, with a maximal impact in Ascó, few kilometers downstream the plant, and a clear reduction at Xerta. This combination of chemical, molecular, cellular and physiological data allowed the precise assessment of the negative impact of the chlor-alkali plant on the quality of river sediments and on fish, and suggests that sediments may be a reservoir for toxic substances even in dynamic environments like rivers.     

High Resolution Membrane Structures within Hybrid Lipid-Polymer Vesicles Revealed by Combining X-Ray Scattering and Electron Microscopy

Hybrid vesicles consisting of phospholipids and block-copolymers are increasingly finding applications in science and technology. Herein, small angle X-ray scattering (SAXS) and cryo-electron tomography (cryo-ET) are used to obtain detailed structural information about hybrid vesicles with different ratios of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and poly(1,2-butadiene-block-ethylene oxide) (PBd₂₂-PEO₁₄, M_s = 1800 g mol⁻¹). Using single particle analysis (SPA) the authors are able to further interpret the information gained from SAXS and cryo-ET experiments, showing that increasing PBd₂₂-PEO₁₄ mole fraction increases the membrane thickness from 52 Å for a pure lipid system to 97 Å for pure PBd₂₂-PEO₁₄ vesicles. Two vesicle populations with different membrane thicknesses in hybrid vesicle samples are found. As these lipids and polymers are reported to homogeneously mix, bistability is inferred between weak and strong interdigitation regimes of PBd₂₂-PEO₁₄ within the hybrid membranes. It is hypothesized that membranes of intermediate structure are not energetically favorable. Therefore, each vesicle exists in one of these two membrane structures, which are assumed to have comparable free energies. The authors conclude that, by combining biophysical methods, accurate determination of the influence of composition on the structural properties of hybrid membranes is achieved, revealing that two distinct membranes structures can coexist in homogeneously mixed lipid-polymer hybrid vesicles.     

Micropallet arrays for the separation of single, adherent cells

The selection and collection of single cells from within a heterogeneous population is required to produce genetically engineered cell lines, to develop new stem cell lines, and for single-cell studies. We describe a new platform for the positive selection of single live mammalian cells while the cells remain adherent to their growth surface. Cells were grown on arrays of microfabricated, releasable elements composed of SU-8 polymer termed "cell pallets". The presence of air between the elements restricted the cells to the top surfaces of the pallets. Single pallets situated within large arrays of pallets were released on demand using a single, focused, laser pulse. The laser pulses were low in energy (2-5 muJ) and did not detach nearby, nontargeted pallets. Since the SU-8 pallets and the underlying glass substrate were optically transparent, the cells on the pallets could be visualized by microscopy before and after release. Over 90% of cells remained attached to the pallet during laser-based release. The feasibility of growing the cells from the released pallets into clonal colonies was demonstrated. The pallet array system permits adherent cells to be inspected using conventional microscopy and selected cells released for further analysis. The ability to assess cells while they remain adherent to a surface will broaden the number of attributes that can be utilized for cell separation, for example, cell shape, cytoskeletal properties, and other attributes.     

Computer Vision System Applied to Classification of “Manila” Mangoes During Ripening Process

Mango is an important crop that is marketed on a large scale around the world. The degree of ripeness of mangoes is an important quality attribute that has traditionally been evaluated manually through their physicochemical properties and color parameters, but recent non-destructive technologies such as computer vision systems (CVS) are emerging to replace these destructive, slow, and costly methods by others that are faster and more reliable. In the present work, physicochemical properties and color parameters obtained using a CVS at laboratory level were linked to establish the ripening stages of mango cv. “Manila.” Classification process involving multivariate analysis was applied with the aim of using only color parameters to estimate levels of ripeness. A set of 117 mangoes was used to estimate the ripening index (RPI) from the physicochemical properties, and another set of 39 mangoes was used to validate the classification process in mangoes harvest in a different season. The RPI was useful for establishing three phases of maturation, namely: pre-climacteric, climacteric, and senescence. These showed correspondences with the color changes evaluated in two color spaces (CIELAB and HSB). Principal component analysis was efficient in selecting the most significant variables and separating the mangoes into the three ripening stages. Multivariate discriminant analysis made it possible to obtain classification rates of 90 % by using only a*, b*, H and S color coordinates, the CIELAB system being, in general, more efficient at classification than HSB. The results obtained showed that CVS developed for the study can be used as a useful non-invasive, efficient method for the evaluation of the ripeness of mangoes.     

Morin functionalized Merrifield’s resin: A new material for enrichment and sensing heavy metals

In this paper, we report the synthesis of morin covalently attached to Merrifield’s resin to be used in metal sorption and recognition. The potential in sensing and sorbent properties of these materials for Cu(II), Pb(II), Zn(II) and Cd(II) in batch and using a flow-through optosensing approach is outlined. The sorption capacity was evaluated in a batch approach using atomic absorption spectroscopy. It was observed that morin modified Merrifield’s resin retained all the studied metals with high efficiency (90-95%). The influence of pH on the ion binding capacity of the resin was investigated by batch method as a function of their fluorescence quenching/enhancement efficiency. The sensing properties of the morin modified beads were also evaluated by packing the resins into a flow-through cell in a FIA (flow injection analysis) format. Results demonstrated that fluorescence emission increased upon Zn²⁺ and Cd²⁺ interaction with a higher sensitivity for Zn²⁺. In contrast, fluorescence quenching was observed when Cu²⁺ and Pb²⁺ were injected and reacted with the resin. The potential applicability of the sensing approach for the selective determination of Cu²⁺ and Zn²⁺ ions is discussed.     

STEM-HAADF electron microscopy analysis of the central dark line defect of human tooth enamel crystallites

When human tooth enamel is observed with the Transmission Electron Microscope (TEM), a structural defect is registered in the central region of their nanometric grains or crystallites. This defect has been named as Central Dark Line (CDL) and its structure and function in the enamel structure have been unknown yet. In this work we present the TEM analysis to these crystallites using the High Angle Annular Dark Field (HAADF) technique. Our results suggest that the CDL region is the calcium richest part of the human tooth enamel crystallites.     

Identification of gadoid fish species using DNA-based techniques

The polymerase chain reaction (PCR) technique was employed to obtain a 464 bp amplicon from the mitochondrial cytochrome b gene from gadoid species to study its ability to differentiate them. The sequences of this fragment from 16 species were analysed using a genetic distance method, and polymorphic sites were determined. The fragment was shown to be moderately polymorphic (151 sites), and this permitted the differentiation of most of the species. A phylogenetic tree construction using Tamura-Nei distances was employed to allow the identification of Gadidae species, each species resulted in a well-differentiated clade, with the exception of Gadus ogac and Gadus macrocephalus, which could not be differentiated. Based on the sequences obtained, three restriction enzymes, Dde I, Hinc II and Nla III, were selected to provide specific restriction profiles, which allowed the differentiation of 15 species of gadoids in a faster and less expensive way than sequencing. The PCR-restriction fragment length polymorphism methodology was also tested using commercial samples.