5,756 research outputs found

    Bronchoalveolar lavage, sputum and exhaled clinically relevant inflammatory markers: values in healthy adults.

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    11noBronchoalveolar lavage (BAL), induced sputum and exhaled breath markers (exhaled nitric oxide and exhaled breath condensate) can each provide biological insights into the pathogenesis of respiratory disorders. Some of their biomarkers are also employed in the clinical management of patients with various respiratory diseases. In the clinical context, however, defining normal values and cut-off points is crucial. The aim of the present review is to investigate to what extent the issue of defining normal values in healthy adults has been pursued for the biomarkers with clinical value. The current authors reviewed data from literature that specifically addressed the issue of normal values from healthy adults for the four methodologies. Most studies have been performed for BAL (n = 9), sputum (n = 3) and nitric oxide (n = 3). There are no published studies for breath condensate, none of whose markers yet has clinical value. In healthy adult nonsmokers the cut-off points (mean+2sd) for biomarkers with clinical value were as follows. BAL: 16.7% lymphocytes, 2.3% neutrophils and 1.9% eosinophils; sputum: 7.7 x 10(6).mL(-1) total cell count and 2.2% eosinophils; nitric oxide: 20.2 ppb. The methodologies differ concerning the quantity and characteristics of available reference data. Studies focusing on obtaining reference values from healthy individuals are still required, more evidently for the new, noninvasive methodologies.nonemixedBALBI B; PIGNATTI P; CORRADI M; BAIARDI P; BIANCHI L; BRUNETTI G; RADAELI A; MOSCATO G; MUTTI A; SPANEVELLO A; MALERBA MBalbi, B; Pignatti, P; Corradi, M; Baiardi, P; Bianchi, L; Brunetti, G; Radaeli, A; Moscato, G; Mutti, A; Spanevello, Antonio; Malerba, M

    Use of natural resins in repairing damaged timber beams – An experimental investigation

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    Different techniques including the application of steel elements, composite materials and polymeric resins have been used in the past to repair damaged timber beams. However, there is a growing need to replace these materials with those with minimal environmental impact. In addition, stringent requirements of conservation authorities on the compatibility between repair and parent materials have also necessitated search for innovative repair materials for timber beams. Therefore, an increasing shift of focus towards the use of materials derived from natural sources in repairing and reinforcing timber structures is currently experienced. This paper presents the results of an exploratory study on the use of natural resins (rosin and bone glue) in repairing oak timber beams. 15 oak timber beams with cross section dimensions of 67 x 67 mm and 1100 mm in length were tested in four-point bending to failure. Undamaged, damaged (unrepaired) and damaged but repaired timber beams (with rosin and bone glue) were tested. The effectiveness of the repair material and technique was analysed based on the bending capacity and mid span deflection at failure. The initial results show negligible effectiveness of rosin in repairing timber beams. In fact, about 16% reduction (average) in load carrying capacity with a corresponding 5% decrease (average) in maximum displacement was recorded. Relatively higher level of effectiveness was recorded with the use of bone glue (about 10 % average increase in load carrying capacity). However, over 30% corresponding average increase in the maximum displacement was also recorded. Further work investigating different repair techniques and other natural resins is presently underway

    Calibration of a visual method for the analysis of the mechanical properties of historic masonry

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    The conservation and preservation of historic buildings affords many challenges to those who aim to retain our building heritage. In this area, the knowledge of the mechanical characteristics of the masonry material is fundamental. However, mechanical destructive testing is always expensive and time-consuming, especially when applied to masonry historic structures. In order to overcome such kind of problems, the authors of this article, proposed in 2014 a visual method for the estimation of some critical mechanical parameters of the masonry material. Based on the fact that the mechanical behavior of masonry material depends on many factors, such as compressive or shear strength of components (mortar and masonry units), unit shape, volumetric ratio between components and stone arrangement, that is the result of applying a series of construction solutions which form the "rule of art". Taking into account the complexity of the problem due to the great number of variables, and being on-site testing a not-always viable solution, a visual estimate of the mechanical parameters of the walls can be made on the basis of a qualitative criteria evaluation. A revision of this visual method is proposed in this paper. The draft version of new Italian Building Code have been used to re-calibrate this visual method and more tests results have been also considered for a better estimation of the mechanical properties of masonry

    Masonry wall panels retrofitted with thermal-insulating GFRP-reinforced jacketing

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    Today there is a need to provide thermally efficient walls, while at the same time to increase the mechanical properties of old unreinforced masonry walls that will not require large amounts of energy in the retrofitting or deconstruction processes. To address this problem, this paper gives the results of shear tests carried out on masonry panels made of solid bricks retrofitted with a new technique based on the use of glass fiber-reinforced polymers (GFRP) grids inserted into a thermal insulating jacketing. This was made of different low-strength lime-based mortars. Tests were carried out in laboratory and results were used for the determination of the shear modulus and strength of the wall panels before and after the application of the GFRP reinforcement. Retrofitted panels exhibited a significant enhancement in the lateral capacity when compared to the control panels. The thermal performance of the proposed mortars was also investigated both with and without GFRP. Low values of thermal conductivity were found, especially for the samples with GFRP; a reduction of the thermal transmittance value in the 34–45 % range was also obtained by applying 45 mm layer of coating in conventional masonry walls

    Independent Information of Nonspecific Biomarkers in Exhaled Breath Condensate

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    Background: Exhaled breath condensate (EBC) has been used for diagnosing and monitoring respiratory disorders. For clinical purposes the assessment of easy-to-obtain nonspecific markers seems particularly interesting. Objectives: As these measures are related to each other, our objective was to extract the independent information in global EBC markers across a range of respiratory disorders. Methods: EBC was collected from patients with asthma (n = 18), chronic obstructive pulmonary disease (n = 17), and cystic fibrosis (n = 46), as well as from lung transplant (LTX) recipients (n = 14) and healthy controls (n = 26). Samples were assessed for electrical conductivity, ammonia, pH, and nitrite/nitrate. pH was measured after both deaeration with argon and CO(2) standardization. Additionally, the fraction of exhaled nitric oxide (FE(NO)) was assessed. Factor analysis was applied to identify major factors concerning these measures. Results: Three independent factors were detected; the first comprised conductivity, ammonia, and pH, especially when standardized using CO(2), the second nitrite/nitrate, and the third FE(NO). Conductivity and ammonia were highly correlated (r = 0.968; p < 0.001). FE(NO) provided independent information mainly in asthma. The nonspecific EBC markers showed considerable overlap between patient groups and healthy subjects. However, conductivity, ammonia, pH standardized for CO(2) and nitrite/nitrate were increased in LTX recipients compared to healthy controls (p < 0.05 each). Conclusions: A panel of nonspecific easy-to-obtain exhaled breath markers could be reduced to 3 independent factors. The information content of conductivity, ammonia, and pH after CO(2) equilibration appeared to be similar, while FE(NO) was independent. The increased levels of these biomarkers in LTX might indicate a potential for their use in these patients. Copyright (C) 2010 S. Karger AG, Base

    Out‐of‐plane reinforcement of masonry walls using joint-embedded steel cables

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    The out-of-plane mechanism (rocking) of walls often causes fatalities and collapses of historic buildings during earthquakes. This paper addresses the problem of assessing the seismic resistance of walls subjected to out-of-plane bending, before and after reinforcement. A new retrofitting method, consisting in the use of high-strength steel cables fully embedded in the mortar bed joints was studied. An experimental investigation using full-scale brickwork specimens was therefore conducted in an attempt to assess the walls’ structural response when these are subject to out-of-plane loads. Test results demonstrated that it is possible to increase the out-of-plane capacity with the proposed method. A simplified macro-element procedure is also presented along with recommendations for the calculation of the walls’ capacity before and after the application of the steel cable reinforcement. Predictions of the magnitude of horizontal force required to cause out-of-plane failure using the proposed procedure and quasi-static analysis procedures are compared with the results of laboratory experiments

    Reinforcement of wood with natural fibers

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    This paper describes an experimental programme which examines the reinforcement in flexure of timber beams with composite materials based on natural fibers in the form of fabrics made from hemp, flax, basalt and bamboo fibers. The industrial use of natural fibers has been continuously increasing since 1990s due to their advantages in terms of production costs, pollution emissions and energy consumption for production and disposal. The technique allows the reinforcement of the intrados of beams, avoiding the dismantling of the overlying part of the structure with significant savings in terms of costs and work time. The test program consists of three phases incorporating 45 beams. The bending tests on the wooden elements made it possible to measure the increase in capacity and stiffness resulting from the composite reinforcement. This was applied to beams, creating different arrangements and using different quantities (number of layers). Despite the diversity of the various tests carried out, the results obtained in some cases showed significant increases in terms of load-carrying capacity and in deflection ductility

    Acute and Chronic Effects of Smoking on Inflammation Markers in Exhaled Breath Condensate in Current Smokers

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    Background: Long-term cigarette smoking is associated with pulmonary inflammation, but the acute effects of smoking have been less well studied. Analysis of the exhaled breath condensate (EBC) can provide noninvasive markers that might be indicative of inflammation. Objectives: The aim of the study was to determine whether the pH, electrical conductivity and the levels of ammonium and interleukin 8 (IL-8) of EBC were altered in smokers and whether they changed after smoking a single cigarette. Methods: We included 19 healthy nonsmokers (controls), 29 asymptomatic smokers, 10 patients with stable chronic obstructive pulmonary disease (COPD) {[}Global Initiative for Chronic Obstructive Lung Disease stages (GOLD) stages II-III], and 10 patients with exacerbated COPD. In 13 smokers, EBC was also analyzed before and after smoking. EBC was obtained during 10 min tidal breathing with a cooled RTube (TM). pH was determined after deaeration with argon. Results: Acute smoking did not alter the pH or ammonium and IL-8 levels, but raised conductivity. As in COPD patients, the pH was significantly decreased in chronic smokers with a history of at least 10 pack-years compared to controls. Conclusions: EBC can be used to detect the acute and chronic effects of smoking. The increased conductivity of EBC after smoking suggests acute inflammatory effects. The reduced pH in chronic smokers shows cigarette-induced inflammation. Copyright (C) 2009 S. Karger AG, Base

    Experimental evaluation of shear and compression strength of masonry wall before and after reinforcement: Deep repointing

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    Masonry presents some inadequacies due to its almost total lack of tensile strength. Typical damage to multiple leaf walls during earthquakes is the loss of bond between the leaves with consequent collapse of the external leaf. Retrofitting or repair of this damage is a very difficult task. In many cases grout injection or wall jacketing fail due to incompatibility with the construction technique of the walls. A complementary technique to the grouting has been proposed by the authors. Experimental results and applications of the technique on site have shown positive characteristics and the results of tests carried out on site show, in some cases, increases in shear strength and stiffness of the masonry walls

    Integrating evidence for managing asthma in patients who smoke

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