Lime mortars with ceramic wastes: characterization of components and their influence on the mechanical behaviour

Considering the fundamental importance of preserving the built heritage and of ensuring the good performance achieved by incorporating ceramic particles in lime mortars in ancient times, it is important to study solutions that use materials the available today, in order to produce mortars intended to repair and replace the old ones. Solutions incorporating industrial ceramic waste might be profitable for several reasons, namely for economic, environmental and technical aspects. In this paper, seven ceramic waste products collected from ceramics factories are characterized. Their mineralogy, dimensional features and pozzolanicity were determined. Three of these products, with different particle size fractions (obtained directly from milling, dust only and fragment fractions only), were selected, incorporated into air lime mortars, and their mechanical strength was determined. In the present work, evidence of mechanical efficiency, when common sand or air lime were partially replaced by ceramic wastes, was made clear, drawing attention to the sustainability of this type of mortars, hence, encouraging further research.

In-line rheo-optical microstructural characterization of complex polymer systems

Tese de Doutoramento em Ciência e Engenharia de Polímeros e Compósitos.

Técnicas Experimentales para Caracterizar Flujos Complejos. Experimental techniques for complex flows characterization.

En ambientes fluviales, la interacción del flujo con la geometría del cauce y con los sedimentos del lecho define una dinámica turbulenta compleja en permanente evolución. El nivel de complejidad del flujo aumenta ante la presencia de estructuras hidráulicas (pilas de puentes, protecciones contra erosión, etc.). La mayoría de los ríos, o canales naturales, presentan confluencias y bifurcaciones, en donde se genera una convergencia (o divergencia) del flujo con el resultado de un ambiente hidrodinámico complejo en la cercanía de las uniones (Kenworthy y Rhoads 1995). Bajo estas condiciones no es posible extrapolar las soluciones tradicionales básicas de las ecuaciones de gobierno desarrolladas para canales rectos y uniformes. Algunas investigaciones experimentales realizadas en estos sistemas son las de Best (1988), Rhoads y Sukhodolov (2001), Richardson et al. (1996); Richardson y Thorne (1998, 2001); Parsons et al. (2004); Szupiany et al. (2005).Por otro lado, la zona costera en ambientes marítimos se caracteriza por la existencia de diversos procesos dinámicos, entre los que se destacan la acción de olas, corrientes, interacción olas-corrientes, transporte de sedimentos y cambios batimétricos. Estos se manifiestan en una alteración morfodinámica de la playa generando superficies potenciales de erosión. Así, el diseño de las protecciones costeras (ya sean continuas, como escolleras o muros verticales; o discontinuas como espigones o diques externos) sometidas al clima marítimo bajo distintas condiciones de olas y mareas, alteran los patrones de circulación y de transporte afectando la morfodinámica en su zona de influencia y plantean, por ejemplo, la necesidad de ajustes de los coeficientes de estabilidad y pesos de los bloques de roca de las escolleras. Los problemas generados, son especialmente complejos ya que deben considerarse para su estudio, los niveles de turbulencia, la transmisión del oleaje sobre o a través de la estructura, difracción alrededor de la misma, refracción y shoaling sobre un fondo dinámico, reflexión en la estructura, etc. (Alsina et al., 2007) Revisiones bibliográficas previas muestran que, en ambos ambientes (fluvial y marítimo), es necesario optimizar las técnicas experimentales existentes para que ellas permitan caracterizar con precisión los flujos turbulentos complejos presentes. El objetivo general propuesto en esta investigación es contribuir a mejorar el conocimiento de los procesos hidrodinámicos de flujos turbulentos naturales con y sin la presencia de estructuras hidráulicas que den lugar a formaciones complejas (3D). Para alcanzar este objetivo se propone realizar una recopilación de antecedentes y un análisis crítico detallado de los equipos de ultima generación para mediciones de flujo con alta frecuencia y resolución disponibles en el Laboratorio de Hidráulica (LH) de la Universidad Nacional de Córdoba (UNC): ADV 3D (Acoustic Doppler Velocimeter de Sontek) y laser PIV 2D (Particle Image Velocimeter de Dantec). A estos equipamientos se le agrega un moderno equipo de generación bidimensional de oleaje con absorción dinámica (adquiridos a HR Ltd. en 2007 por el CAI 085 del FONTAR). Finalmente se prevé utilizar este equipamiento durante el desarrollo de experimentos y mediciones los cuales se realizarán sobre modelos físicos fluviales y costeros diseñados y construidos con y sin estructuras que interactúen con flujo turbulentos complejos. Los resultados obtenidos en este proyecto permitirá alcanzar una mejor comprensión de los procesos hidrodinámicos de los flujos turbulentos complejos, lo cual es necesario y de gran utilidad para realizar un manejo apropiado de los ambientes fluviales y marítimos, teniendo como campo directo de aplicación el correcto diseño de estructuras hidráulicas, asistiendo a la toma de medidas correctivas en sistemas naturales sometidos a procesos erosivos o de sedimentación, y contribuyendo de esta forma al manejo ambientalmente sustentable de los recursos.

Functional Characterization of a n NTPase Activity of the Hepatitis C Virus Nonstructural Protein 4B

Background: Nonstructural p rotein 4 B (NS4B) i s the m asterorganizer of hepatitis C virus (HCV) replication complexformation. It is a multispanning membrane protein that has beenreported to p ossess NTPase activity. This enzymatic functionhas been poorly studied so far and its role in the HCV life cycleis u nknown. T he present w ork-in-progress a ims at validatingand functionally c haracterizing this a ctivity a nd its r ole in t heviral life cycle.Methods: B ioinformatic analyses were performed to i dentifykey residues for site-directed mutagenesis, both in t he contextof s ubgenomic r eplicons a s well as recombinant v iruses.Mutants were investigated with respect to R NA replication andinfectious particle p roduction. In p arallel, expression andpurification of recombinant wild-type and mutant NS4B proteinsare being pursued to characterize enzymatic activity in vitro.Results: B ioinformatic a nalyses revealed t hat p redictedNTPase features are conserved only in H CV NS4B b ut n ot i nNS4B from other Flaviviridae f amily m embers. A laninesubstitutions were designed to target predicted key Walker A, Band C motifs. These substitutions affected RNA replication andinfectious virus production to v arying degrees. Optimization ofrecombinant protein production is i n progress both in b acterialas well as mammalian expression systems.Conclusions: These studies should yield new insights into thefunctions of this hitherto poorly characterized viral nonstructuralprotein and may reveal novel targets for antiviral intervention inthe future.

Manufacturing and characterization of a recombinant adeno-associated virus type 8 reference standard material.

Gene therapy approaches using recombinant adeno-associated virus serotype 2 (rAAV2) and serotype 8 (rAAV8) have achieved significant clinical benefits. The generation of rAAV Reference Standard Materials (RSM) is key to providing points of reference for particle titer, vector genome titer, and infectious titer for gene transfer vectors. Following the example of the rAAV2RSM, here we have generated and characterized a novel RSM based on rAAV serotype 8. The rAAV8RSM was produced using transient transfection, and the purification was based on density gradient ultracentrifugation. The rAAV8RSM was distributed for characterization along with standard assay protocols to 16 laboratories worldwide. Mean titers and 95% confidence intervals were determined for capsid particles (mean, 5.50×10(11) pt/ml; CI, 4.26×10(11) to 6.75×10(11) pt/ml), vector genomes (mean, 5.75×10(11) vg/ml; CI, 3.05×10(11) to 1.09×10(12) vg/ml), and infectious units (mean, 1.26×10(9) IU/ml; CI, 6.46×10(8) to 2.51×10(9) IU/ml). Notably, there was a significant degree of variation between institutions for each assay despite the relatively tight correlation of assay results within an institution. This outcome emphasizes the need to use RSMs to calibrate the titers of rAAV vectors in preclinical and clinical studies at a time when the field is maturing rapidly. The rAAV8RSM has been deposited at the American Type Culture Collection (VR-1816) and is available to the scientific community.

Characterization of modern and fossil mineral dust transported to high altitude in the Western Alps: Saharan sources and transport patterns

Mineral dust aerosols recently collected at the high-altitude Jungfraujoch research station (46 degrees 33'51 `' N, 7 degrees 59'06 `' E; 3580 m a.s.l.) were compared to mineral dust deposited at the Colle Gnifetti glacier (45 degrees 52'50 `' N, 7 degrees 52'33 `' E; 4455 m a.s.l.) over the last millennium. Radiogenic isotope signatures and backward trajectories analyses indicate that major dust sources are situated in the north-central to north-western part of the Saharan desert. Less radiogenic Sr isotopic compositions of PM10 aerosols and of mineral particles deposited during periods of low dust transfer likely result from the enhancement of the background chemically-weathered Saharan source. Saharan dust mobilization and transport were relatively reduced during the second part of the Little Ice Age (ca. 1690-1870) except within the greatest Saharan dust event deposited around 1770. After ca. 1870, sustained dust deposition suggests that increased mineral dust transport over the Alps during the last century could be due to stronger spring/summer North Atlantic southwesterlies and drier winters in North Africa. On the other hand, increasing carbonaceous particle emissions from fossil fuel combustion combined to a higher lead enrichment factor point to concomitant anthropogenic sources of particulate pollutants reaching high-altitude European glaciers during the last century.

Physicochemical and biological characterization of single-walled and double-walled carbon nanotubes in biological media

To study the toxicity of nanoparticles under relevant conditions, it is important to reproducibly disperse nanoparticles in biological media in in vitro and in vivo studies. Here, single-walled nanotubes (SWNTs) and double-walled nanotubes (DWNTs) were physicochemically and biologically characterized when dispersed in phosphate-buffered saline (PBS) and bovine serum albumin (BSA). BSA-SWNT/DWNT interaction resulted in a reduction of aggregation and an increase in particle stabilization. Based on the protein sequence coverage and protein binding results, DWNTs exhibited higher protein binding than SWNTs. SWNT and DWNT suspensions in the presence of BSA increased interleukin-6 (IL-6) levels and reduced tumor necrosis factor-alpha (TNF-α) levels in A549 cells as compared to corresponding samples in the absence of BSA. We next determined the effects of SWNTs and DWNTs on pulmonary protein modification using bronchoalveolar lavage fluid (BALF) as a surrogate collected form BALB/c mice. The BALF proteins bound to SWNTs (13 proteins) and DWNTs (11 proteins), suggesting that these proteins were associated with blood coagulation pathways. Lastly, we demonstrated the importance of physicochemical and biological alterations of SWNTs and DWNTs when dispersed in biological media, since protein binding may result in the misinterpretation of in vitro results and the activation of protein-regulated biological responses.

Properties of debris flow deposits and source materials compared: implications for debris flow characterization

In the Alps, debris flow deposits generally contain < 5% clay-size particles, and the role of the surface-charged < 2 mu m particles is often neglected, although these particles may have a significant impact on the rheological properties of the interstitial fluid. The objective of this study was to compare debris flow deposits and parent materials from two neighbouring catchments of the Swiss Alps, with special emphasis on the colloidal constituents. The catchments are small in area (4 km(2)), 2.5 km long, similar in morphology, but different in geology. The average slopes are 35-40%. The catchments were monitored for debris flow events and mapped for surface aspect and erosion activity. Debris flow deposits and parent materials were sampled, the clay and silt fractions extracted and the bulk density, < 2 mm fraction bulk density, particle size distribution, chemical composition, cation exchange capacity (CEC) and mineralogy analysed. The results show that the deposits are similar to the parent screes in terms of chemical composition, but differ in terms of: (i) particle size distribution; and (ii) mineralogy, reactivity and density of the < 2 mm fraction. In this fraction, compared with the parent materials the deposits show dense materials enriched in coarse monocrystalline particles, of which the smallest and more reactive particles were leached. The results suggest that deposit samples should not be considered as representative of source or flow materials, particularly with respect to their physical properties.

Characterization of surface functional groups present on laboratory-generated and ambient aerosol particles by means of heterogeneous titration reactions

A Knudsen flow reactor has been used to quantify surface functional groups on aerosols collected in the field. This technique is based on a heterogeneous titration reaction between a probe gas and a specific functional group on the particle surface. In the first part of this work, the reactivity of different probe gases on laboratory-generated aerosols (limonene SOA, Pb(NO3)2, Cd(NO3)2) and diesel reference soot (SRM 2975) has been studied. Five probe gases have been selected for the quantitative determination of important functional groups: N(CH3)3 (for the titration of acidic sites), NH2OH (for carbonyl functions), CF3COOH and HCl (for basic sites of different strength), and O3 (for oxidizable groups). The second part describes a field campaign that has been undertaken in several bus depots in Switzerland, where ambient fine and ultrafine particles were collected on suitable filters and quantitatively investigated using the Knudsen flow reactor. Results point to important differences in the surface reactivity of ambient particles, depending on the sampling site and season. The particle surface appears to be multi-functional, with the simultaneous presence of antagonistic functional groups which do not undergo internal chemical reactions, such as acid-base neutralization. Results also indicate that the surface of ambient particles was characterized by a high density of carbonyl functions (reactivity towards NH2OH probe in the range 0.26-6 formal molecular monolayers) and a low density of acidic sites (reactivity towards N(CH3)3 probe in the range 0.01-0.20 formal molecular monolayer). Kinetic parameters point to fast redox reactions (uptake coefficient ?0>10-3 for O3 probe) and slow acid-base reactions (?0<10-4 for N(CH3)3 probe) on the particle surface. [Authors]

Characterization of Tomato yellow spot virus, a novel tomato-infecting begomovirus in Brazil

The objective of this work was the biological and molecular characterization of a begomovirus detected in São Joaquim de Bicas, Minas Gerais, Brazil, named TGV-[Bi2], by determining its host range, complete nucleotide sequence and phylogenetic relationships with other begomoviruses. Biological characterization consisted of a host range study using either sap inoculation or particle bombardment as inoculation methods. The yellow spot virus can infect plants in Solanaceae and Amaranthaceae, including economically importat crops as sweet pepper, and weeds as Datura stramonium and Nicotiana silvestris. For the molecular characterization, the full-length genome (DNA-A and DNA-B) was amplified, cloned and completely sequenced. Sequence comparisons and phylogenetic analyses indicated that TGV-[Bi2] constitutes a novel begomovirus species named Tomato yellow spot virus (ToYSV), closely related to Sida mottle virus (SiMoV).

Characterization of membrane vesicles circulating in the serum of patients with common acute lymphoblastic leukemia.

Common acute lymphoblastic leukemia antigen detected by radioimmunoassay in the serum of patients with common acute lymphoblastic leukemia was found to be exclusively associated with the pellet of the serum samples obtained by ultracentrifugation at 100,000 X g. The pellets were shown to contain membrane vesicles or fragments which were characterized by electron microscopy and determination of enzymatic activity. The pelleted fragments had an apparent diameter ranging between 60 and 260 nm and showed a trilaminar membrane structure. On freeze-fracture preparations, the fragments with concave profile, corresponding to the external fracture face of plasma membrane, displayed an intramembrane particle density (ranging from 0 to 750 particles per micron2) which is similar to that recorded on the corresponding fracture face of intact cells from the common lymphoblastic leukemia antigen positive leukemic cell line (Nalm-1) or of vesicles shed in the culture medium by Nalm-1 cells. Furthermore, analysis of the membrane enzyme marker 5'-nucleotidase in the pellet of patient's sera, showed that the presence of this enzyme correlated with that of common lymphoblastic leukemia antigen, but the quantitative relationship between the two surface constituents was not linear. The results suggest that the two markers are located on the same membrane fragments, but that their individual distribution on the shed fragments is heterogeneous.

Physico-chemical characterization and oxidative reactivity evaluation of aged brake wear particles

Brake wear dust is a significant component of traffic emissions and has been linked to adverse health effects. Previous research found a strong oxidative stress response in cells exposed to freshly generated brake wear dust. We characterized aged dust collected from passenger vehicles, using microscopy and elemental analyses. Reactive oxygen species (ROS) generation was measured with acellular and cellular assays using 2′7-dichlorodihydrofluorescein dye. Microscopy analyses revealed samples to be heterogeneous particle mixtures with few nanoparticles detected. Several metals, primarily iron and copper, were identified. High oxygen concentrations suggested that the elements were oxidized. ROS were detected in the cell-free fluorescent test, while exposed cells were not dramatically activated by the concentrations used. The fact that aged brake wear samples have lower oxidative stress potential than fresh ones may relate to the highly oxidized or aged state of these particles, as well as their larger size and smaller reactive surface area.

Physicochemical characterization of nebulized superparamagnetic iron oxide nanoparticles (SPIONs)

Abstract Background: Aerosol-mediated delivery of nano-based therapeutics to the lung has emerged as a promising alternative for treatment and prevention of lung diseases. Superparamagnetic iron oxide nanoparticles (SPIONs) have attracted significant attention for such applications due to their biocompatibility and magnetic properties. However, information is lacking about the characteristics of nebulized SPIONs for use as a therapeutic aerosol. To address this need, we conducted a physicochemical characterization of nebulized Rienso, a SPION-based formulation for intravenous treatment of anemia. Methods: Four different concentrations of SPION suspensions were nebulized with a one-jet nebulizer. Particle size was measured in suspension by transmission electron microscopy (TEM), photon correlation spectroscopy (PCS), and nanoparticle tracking analysis (NTA), and in the aerosol by a scanning mobility particle sizer (SMPS). Results: The average particle size in suspension as measured by TEM, PCS, and NTA was 9±2 nm, 27±7 nm, and 56±10 nm, respectively. The particle size in suspension remained the same before and after the nebulization process. However, after aerosol collection in an impinger, the suspended particle size increased to 159±46 nm as measured by NTA. The aerosol particle concentration increased linearly with increasing suspension concentration, and the aerodynamic diameter remained relatively stable at around 75 nm as measured by SMPS. Conclusions: We demonstrated that the total number and particle size in the aerosol were modulated as a function of the initial concentration in the nebulizer. The data obtained mark the first known independent characterization of nebulized Rienso and, as such, provide critical information on the behavior of Rienso nanoparticles in an aerosol. The data obtained in this study add new knowledge to the existing body of literature on potential applications of SPION suspensions as inhaled aerosol therapeutics.

Time-series forecasting of pollutant concentration levels using particle swarm optimization and artificial neural networks

This study evaluates the application of an intelligent hybrid system for time-series forecasting of atmospheric pollutant concentration levels. The proposed method consists of an artificial neural network combined with a particle swarm optimization algorithm. The method not only searches relevant time lags for the correct characterization of the time series, but also determines the best neural network architecture. An experimental analysis is performed using four real time series and the results are shown in terms of six performance measures. The experimental results demonstrate that the proposed methodology achieves a fair prediction of the presented pollutant time series by using compact networks.

Inhalable particulate matter characterization in a medium-sized urban region in Brazil (São José dos Campos Town) - Part I: Morphology

In this study, the concentration and morphological characteristics of inhalable particulate material (PM10) were evaluated and associated with climatic conditions. The mean annual concentration was 11.0 µg m−3, varying between 0,647 µg m−3 and 36.8 µg m−3. Wind speed has a higher influence on PM10 dispersion, but direction was associated with particle source. During the wet period, wind speed is the main dispersion factor, while speed and direction both are important during the dry period. Based on the morphological characteristics, it is concluded that biogenic particles prevail during the rainy season and terrigenous particles during the dry period, depending on the wind direction and intensity.