40,032 research outputs found
Erratum to: Effect of moderate red wine intake on cardiac prognosis after recent acute myocardial infarction of subjects with Type 2 diabetes mellitus (Diabetic Medicine, (2006), 23, 9, (974-981), 10.1111/j.1464-5491.2006.01886.x)
No full textIn an article by Marfella et al, the author name C. Saron is incorrect and should be listed as C. Sardu. Therefore the correct author list is: R. Marfella, F. Cacciapuoti, M. Siniscalchi, F. C. Sasso, F. Marchese, F. Cinone, E. Musacchio, M. A. Marfella, L. Ruggiero, G. Chiorazzo, D. Liberti, G. Chiorazzo, G. F. Nicoletti, C. Sardu, F. D'Andrea, C. Ammendola, M. Verza and L. Coppola.In an article by Marfella et al, the author name C. Saron is incorrect and should be listed as C. Sardu. Therefore the correct author list is: R. Marfella, F. Cacciapuoti, M. Siniscalchi, F. C. Sasso, F. Marchese, F. Cinone, E. Musacchio, M. A. Marfella, L. Ruggiero, G. Chiorazzo, D. Liberti, G. Chiorazzo, G. F. Nicoletti, C. Sardu, F. D'Andrea, C. Ammendola, M. Verza and L. Coppola
Centrifuge and numerical modelling of twin-propped retaining walls.
No full textPhDA series of tests on flexible model diaphragm walls embedded in an
overconsolidated clay was carried out at the London Geotechnical Centrifuge
Centre. The walls were propped at the crest and, following the simulation of
excavation, were propped at formation level. Although a retained height of 10m
was modelled in all tests, the depth of embedment below dredge level varied
between Sm, 10m and 15m. A 'softer' propping sequence was also investigated
with excavation to 5m below the retained surface prior to the installation of the
crest level prop then, following further excavation to dredge level, the bottom
prop was installed. The pre-excavation lateral earth pressure was also
investigated.
The background and use of twin-propped retaining walls is discussed together
'with the design of the centrifuge model and modelling procedure. The results of
the tests are presented and the effects of embedment depth, construction sequence
and pre-excavation lateral earth pressure coefficient is discussed.
A series of finite element analyses using the critical state soils program CRISP
was undertaken in which it was attempted to model the centrifuge models.
Generally, results were in reasonable agreement, although it was discovered that
the calculated wall movements and prop loads were sensitive to the slope of the
Hvorslev surface required for the Schofield soil model used in the analyses.
The prop loads from the centrifuge tests and finite element analyses were
compared with prop loads calculated using popular empirical methods and with
prop loads observed on site. Generally, prop loads were underpredicted using the
empirical methods which are unable to account for construction sequence effects
and probably overestimate the degree of lateral stress reduction that takes place
during excavation.TR
Elaboration on Kwapien's theorem: Representing bounded mean zero functions f as coboundary f = g ◦ T − g
No full textIn [8] Kwapien proved that every mean zero function f ∈ L∞[0, 1] we can write as f = g ◦ T − g for some g ∈ L∞[0, 1] and some measure preserving transformation T of [0, 1]. However, as was discovered in [4] there is a gap in the proof for the case that f is not continuous. The aim of this bachelor thesis is filling in that gap in the proof. We first extend Kwapien’s proof for continuous functions to certain other measure spaces. Thereafter, we use the method of proof suggested by Kwapien, to proof the theorem for mean zero function f ∈ L∞[0, 1] for which λ(f−1({x})) = 0 for all x ∈ R. Using this result we then proof that every mean zero function f ∈ L∞[0, 1] can be written as a sum f =(g1 ◦ T1 − g1) + (g2 ◦ T2 − g2) where g1, g2 ∈ L∞[0, 1] and where T1, T2 are measure preserving transformations of [0, 1]. We finish this thesis with an application of Kwapien’s theorem in the study to singular traces Applied Mathematic
The inhibition of mast cell activation by neutrophil lactoferrin: uptake by mast cells and interaction with tryptase, chymase and cathepsin G
No full textInhibitors of mast cell tryptase and chymase can be effective as mast cell stabilising compounds. Lactoferrin has been reported to inhibit tryptase activity, but its actions on other serine proteases of mast cells and its potential to alter mast cell function are not known. We have examined the ability of lactoferrin to inhibit mast cell tryptase, chymase and cathepsin G, and investigated its potential to modulate the activation of human mast cells. Enzymatically dispersed cells from human skin, lung and tonsil were challenged with anti-IgE or calcium ionophore A23187, following incubation with recombinant human lactoferrin, and histamine release determined. IgE-dependent histamine release from skin mast cells was inhibited by up to 50% following incubation with lactoferrin (50 or 500 nM). Tonsil mast cells were also stabilised by lactoferrin, but not those from lung. Calcium ionophore A23187-induced histamine release was not altered by lactoferrin. A double-labelling immunocytochemical procedure revealed the presence of lactoferrin in 4–6% of mast cells, and this proportion increased to 40% following incubation with lactoferrin. Lactoferrin did not inhibit cleavage of synthetic substrates by tryptase and chymase directly, though it was able to diminish the ability of heparin to stabilise tryptase. Cathepsin G activity was inhibited by lactoferrin. The ability of lactoferrin to inhibit IgE-dependent activation of human mast cells and modulate protease activity suggests that the release of this neutrophil product may have a role in the downregulation of allergic inflammation. <br/
Behaviour of masonry walls strengthened with fibre-reinforced cementitious materials
No full textAssessment of the mechanical properties of masonry materials is a key issue for evaluating the strength capacity of masonry walls. Two types of test are usually adopted for experimentally evaluating the shear capacity of masonry walls: diagonal-compression and shear-compression. Different approaches are available in the literature for their interpretation. This paper reports on an investigation into the behaviour of both unstrengthened and in-plane-strengthened masonry walls with fibre-reinforced cementitious matrix materials under the two tests by means of a bi-dimensional not-linear-finite-element model. The model was firstly calibrated on the basis of comparisons with experimental results of diagonal compression tests available in the literature. It was then used for comparing the numerical results obtained for the two tests in terms of local stress distributions for both unstrengthened and strengthened walls. The differences in the stress distributions in the tests, and the role of the reinforcement both on the distribution of stresses and on the global behaviour of the masonry walls, was highlighted
Experimental estimation of energy dissipation in rocking masonry walls restrained by an innovative seismic dissipator (LICORD)
No full textThis paper presents an innovative anti-seismic device for controlling the out-of-plane rocking motion of masonry walls with traditional tie-rods, called LInear COntrolled Rocking Device (LICORD). LICORD is a low-impact box connected to the extremity of the traditional tie-rod designed to mitigate rocking for medium–high intensity earthquakes. Additionally, the paper widens the knowledge about the dynamic behavior of rocking walls through the interpretation of the results of an extensive experimental campaign performed on masonry specimens composed by clay brick and cementitious mortar. Firstly, the LICORD’s single components are tested to identify their stiffness and damping properties. Secondly, free vibration tests provide actual values of coefficients of restitution on free-standing walls and walls restrained by LICORD, where the walls vary for the height to thickness ratio. For the stockier wall, the ratio of experimental/analytical coefficient of restitution varies from 88 to 98%, whereas for the slender wall, the results are less scattered, with a minimum value of 95% and a maximum value of 96%. The restrained walls are characterized by coefficients of restitution from 5 to 25% less than the values found for unrestrained walls, depending on the equivalent viscous coefficient of the shock absorbers. Moreover, LICORD demonstrated to properly absorb and damp the oscillations of the wall and control its rocking motion, strongly reducing the number of impacts and the rotation amplitudes up to 70%. Considerations about the effect of one-sided motion on the assessment of coefficient of restitution are also given. The equivalent viscous damping coefficients are observed to be on the range 4% (unrestrained wall) and 7–20% for walls restrained by LICORD
Diagonal compression of masonry walls strengthened with composite reinforced mortar
No full textThe use of inorganic matrix composites to strengthen and retrofit existing masonry and
concrete structures has been gaining increasing interest in the last years. Among them, composite
reinforced mortar (CRM) systems are a promising solution to increase the shear and flexural
capacity of masonry panels. CRMs are comprised of a relatively thin inorganic matrix layer
reinforced with a bi-dimensional grid made with high-strength fibers impregnated with an organic
matrix. They are compatible with the substrate due to the use of inorganic matrix, have good
durability and high-strength-to weight ratio due to the use of reinforcing composite materials. CRM
systems are still in their infancy and limited research is available in the literature.
In this paper, masonry walls constructed with historical bricks typical of the north of Italy were
strengthened with a CRM system including a glass composite grid and a lime-based mortar and
were subjected to diagonal compression. Three walls were strengthened with the CRM and one was
used as a control specimen. The results obtained showed that the CRM system significantly
increased the shear strength of the masonry panels subjected to diagonal compression
TWO-PHOTON SPECTROSCOPY OF THE AND STATES OF
No full text Research supported by AFOSR K. Hoshiba et al. J. Phys. B 18, 1.875 (1985). T. Sakai et al., J. Phys. B. 21, 229 (1988).Author Institution: Molecular Physics Laboratory, SRI InternationalThe and states of are excited from the ground by two photons near 207 nm and detected by vuv fluorescence or by ionization by a third photon. The laser source for these measurements is an excimer-pumped dye laser operating with PBBO dye at 415 nm. This light is doubled in a crystal and focused into a cell containing a mixture of in He. The uv wavelengths were calibrated against the (3.0) band in NO, which was calibrated against in the visible. Vibrational levels were observed in the state and in the state, based on the previous electron-impact , and partially resolved rotationally (the effective excitation linewidth is ). These assignments are supported by simulations of the two-photon excitation spectra. Although the fluorescence has not yet been spectrally resolved, we believe that it arises predominantly from the triplet state even when the singlet is initially excited. In the latter case, the fluorescence is temporally delayed, and increases in intensity as the He density is increased. The two-phonon excitation scheme we have developed should be useful in investigating the kinetics of the 158 nm laser, which is believed to arise from a transition from the outer well of the state to a weakly bound state correlating to ground state atoms.$^{2}
Probing the molecular architecture of Arabidopsis thaliana secondary cell walls using two- and three-dimensional 13C solid state nuclear magnetic resonance spectroscopy
No full textThe plant secondary cell wall is a thickened polysaccharide and phenolic structure, providing mechanical strength to cells, particularly in woody tissues. It is the main feedstock for the developing bioenergy and green chemistry industries. Despite the role that molecular architecture (the arrangement of biopolymers relative to each other, and their conformations) plays in dictating biomass properties, such as recalcitrance to breakdown, it is poorly understood. Here, unprocessed dry 13C-labeled stems from the model plant Arabidopsis thaliana were analyzed by a variety of 13C solid state magic angle spinning nuclear magnetic resonance methods, such as one-dimensional cross-polarization and direct polarization, two-dimensional refocused INADEQUATE, RFDR, PDSD, and three-dimensional DARR, demonstrating their viability for the study of native polymer arrangements in intact secondary cell walls. All carbon sites of the two main glucose environments in cellulose (previously assigned to microfibril surface and interior residues) are clearly resolved, as are carbon sites of the other major components of the secondary cell wall: xylan and lignin. The xylan carbon 4 chemical shift is markedly different from that reported previously for solution or primary cell wall xylan, indicating significant changes in the helical conformation in these dried stems. Furthermore, the shift span indicates that xylan adopts a wide range of conformations in this material, with very little in the 31 conformation typical of xylan in solution. Additionally, spatial connections of noncarbohydrate species were observed with both cellulose peaks conventionally assigned as “surface” and as “interior” cellulose environments, raising questions about the origin of these two cellulose signals. In woody plant tissues, a secondary cell wall is laid down on the interior of the thin, extensible, and biochemically and functionally distinct primary cell wall during cellular differentiation. The secondary wall is crucial to many aspects of plant physiology, including mechanical strength. It also comprises the vast majority of the material of mature plant tissues and lignocellulosic biomass and is therefore an invaluable resource for renewable materials and for bioenergy feedstocks.1,2 The polysaccharide components of the cell wall, which constitute more than 60% of its dry weight, are commonly categorized into three constituent types: cellulose, hemicellulose, and pectin.3,4 Cellulose is thought to be the main load-bearing structure of the cell wall and is the most abundant polymer in both primary and secondary walls.5 Cellulose chains are composed of β-(1→4)-D-glucosyl residues (Figure 1) that are partly assembled into layers in a microfibril by inter- and intrachain hydrogen bonding and hydrophobic interactions. Within crystalline regions of cellulose microfibrils (known as crystallites), glucan chains are found in a 2-fold (21) helical conformation
Free product subgroups between Chevalley groups G(Φ,F) and G(Φ,F[t])
No full textAbstractWe investigate subgroups of a Chevalley group G=G(Φ,A) over a ring A, containing its elementary subgroup E=E(Φ,F) over a subring F⊆A. Assume that the root system Φ is simply laced and A=F[t] is a polynomial ring. We show that if G is of adjoint type, then there exists an element g∈E(Φ,A) such that 〈g,E(Φ,F)〉=〈g〉*E(Φ,F), where 〈X〉 denotes the subgroup, generated by a set X, and * stands for the free product.It follows that under the above assumptions the lattice L=L(E,G) is not standard. Moreover, combining the above result with theorems of Nuzhin and the author one obtains a necessary and sufficient condition for L to be standard provided that A and F are fields of characteristic not 2 and Φ≠G2
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