Dynamics of driven three-dimensional thin films: from hdrophilic to superhydrophobic substrates

We study the forced displacement of a thin film of fluid in contact with vertical and inclined substrates of different wetting properties, that range from hydrophilic to hydrophobic, using the lattice-Boltzmann method. We study the stability and pattern formation of the contact line in the hydrophilic and superhydrophobic regimes, which correspond to wedge-shaped and nose-shaped fronts, respectively. We find that contact lines are considerably more stable for hydrophilic substrates and small inclination angles. The qualitative behavior of the front in the linear regime remains independent of the wetting properties of the substrate as a single dispersion relation describes the stability of both wedges and noses. Nonlinear patterns show a clear dependence on wetting properties and substrate inclination angle. The effect is quantified in terms of the pattern growth rate, which vanishes for the sawtooth pattern and is finite for the finger pattern. Sawtooth shaped patterns are observed for hydrophilic substrates and low inclination angles, while finger-shaped patterns arise for hydrophobic substrates and large inclination angles. Finger dynamics show a transient in which neighboring fingers interact, followed by a steady state where each finger grows independently.

Understanding and modulating the competitive surface-adsorption of proteins through coarse-grained molecular dynamics simulations

It is now well accepted that cellular responses to materials in a biological medium reflect greatly the adsorbed biomolecular layer, rather than the material itself. Here, we study by molecular dynamics simulations the competitive protein adsorption on a surface (Vroman effect), i.e. the non-monotonic behavior of the amount of protein adsorbed on a surface in contact with plasma as functions of contact time and plasma concentration. We find a complex behavior, with regimes during which small and large proteins are not necessarily competing between them, but are both competing with others in solution ("cooperative" adsorption). We show how the Vroman effect can be understood, controlled and inverted.

Multiplex PCR of sonication fluid accurately differentiates between prosthetic joint infection and aseptic failure.

OBJECTIVE: Cultures have limited sensitivity in the diagnosis of prosthetic joint infection (PJI), especially in low-grade infections. We assessed the value of multiplex PCR in differentiating PJI from aseptic failure (AF). METHODS: Included were patients in whom the joint prosthesis was removed and submitted for sonication. The resulting sonication fluid was cultured and investigated by multiplex PCR, and compared with periprosthetic tissue culture. RESULTS: Among 86 explanted prostheses (56 knee, 25 hip, 3 elbow and 2 shoulder prostheses), AF was diagnosed in 62 cases (72%) and PJI in 24 cases (28%). PJI was more common detected by multiplex PCR (n=23, 96%) than by periprosthetic tissue (n=17, 71%, p=0.031) or sonication fluid culture (n=16, 67%, p=0.016). Among 12 patients with PJI who previously received antibiotics, periprosthetic tissue cultures were positive in 8 cases (67%), sonication fluid cultures in 6 cases (50%) and multiplex PCR in 11 cases (92%). In AF cases, periprosthetic tissue grew organisms in 11% and sonication fluid in 10%, whereas multiplex PCR detected no organisms. CONCLUSIONS: Multiplex PCR of sonication fluid demonstrated high sensitivity (96%) and specificity (100%) for diagnosing PJI, providing good discriminative power towards AF, especially in patients previously receiving antibiotics.

Video-assisted thoracic surgery diagnosis of thoracic spinal tuberculosis.

Tuberculous spondylitis is rare in economically well-developed countries. MRI is the most sensitive radiologic method of diagnosis. CT-guided fine needle aspiration can be an appropriate method for obtaining samples for culture, with positive cultures in 25 to 89% of cases. However, it can take >6 weeks for specimens to grow, and it is essential to have adequate culture and sensitivity studies for the diagnosis and treatment of mycobacterial diseases. We propose a minimally invasive diagnostic approach that ensures that adequate surgical specimens are obtained prior to initiating treatment.

Back Warning Sensors for Tow Plows, RB07-012, 2013

Backup warning system devices were evaluated to determine if they would alert winter maintenance snow plow drivers to obstacles directly behind the trailer and out of view of the driver when a unit is backed up. When the sensors on the back of the tow plow were covered with snow during plowing operations, the sensor would go off in the cab and continue going off, which would result in drivers turning the volume of the unit way down. One shop stated that the wireless transmitted signal would be hit or miss depending on the winter weather that they were operating in. The sensors on the back of the tow plow trailer would come in contact with salt brine and in this situation one of the sensors did go bad. The weatherproof box that was designed to keep the system waterproof did not fully keep the moisture out. It was found that the system did alert drivers of items behind the unit and there were no backup accidents reported during the research period.

Antibacterial burst-release from minimal Ag-containing plasma polymer coatings.

Biomaterials releasing silver (Ag) are of interest because of their ability to inhibit pathogenic bacteria including antibiotic-resistant strains. In order to investigate the potential of nanometre-thick Ag polymer (Ag/amino-hydrocarbon) nanocomposite plasma coatings, we studied a comprehensive range of factors such as the plasma deposition process and Ag cation release as well as the antibacterial and cytocompatible properties. The nanocomposite coatings released most bound Ag within the first day of immersion in water yielding an antibacterial burst. The release kinetics correlated with the inhibitory effects on the pathogens Pseudomonas aeruginosa or Staphylococcus aureus and on animal cells that were in contact with these coatings. We identified a unique range of Ag content that provided an effective antibacterial peak release, followed by cytocompatible conditions soon thereafter. The control of the in situ growth conditions for Ag nanoparticles in the polymer matrix offers the possibility to produce customized coatings that initially release sufficient quantities of Ag ions to produce a strong adjacent antibacterial effect, and at the same time exhibit a rapidly decaying Ag content to provide surface cytocompatibility within hours/days. This approach seems to be favourable with respect to implant surfaces and possible Ag-resistance/tolerance built-up.

L’educació intercultural. Un repte a l’aula de P4 d’una escola de la comarca de la Garrotxa

Des de l’educació intercultural es pretén aconseguir una societat més justa i igualitària capaç de respectar la diversitat cultural sense prejudicis, fomentant el diàleg i la convivència com una possibilitat per apropar les diferents cultures, on la participació dels diferents agents educatius és fonamental. Aquest treball mostra la investigació realitzada en una aula, d’infants de quatre anys d’una escola de la comarca de la Garrotxa, per valorar si la seva pràctica educativa segueix una línia intercultural. S’ha fet ús d’una metodologia qualitativa per mitjà de l’observació, l’entrevista i l’anàlisi de documents que ha posat de manifest la importància del professorat en tenir una actitud positiva cap a la comprensió i interacció entre diferents cultures per tal de caminar cap a la interculturalitat.

Experiències poètiques de qualitat a la infància

La poesia és un gènere literari, massa sovint, oblidat a les escoles. No obstant, està demostrat que es pot treballar amb persones de totes les edats, des d’infants ben petits, fins a persones adultes, sempre i quan, les metodologies i les tècniques utilitzades siguin adequades als receptors. Aquest gènere no implica només comprensió del vocabulari i del missatge final, sinó també comporta gaudir del joc de les paraules, dels sons, de la melodia, del ritme... Es pot dir, doncs, que poesia i música, són dues arts que estan estretament relacionades. Quins elements provoquen que una experiència de poesia tingui qualitat? En primer lloc, el “què”, quin tipus de poesia oferim als infants. Així doncs, els podem proporcionar poesia escrita per a infants, però també poesia , en un inici, pensada per a adults. I és que el poema que és bo per a nens/es també ho és per a gent més gran, i a l’inrevés. A més a més, la poesia ha de ser rítmica, melòdica i que busqui constantment el joc sonor de les paraules. En segon lloc, el “qui”, és a dir, quines condicions ha de tenir la persona que escriu i recita poesia, per fer-ho amb la màxima qualitat possible. L’escriptor ha de ser una persona culta, amb un profund lligam artístic. No tothom serveix per a ser un bon escriptor, ja que comporta una gran tasca . Pel que fa a l’art de recitar, és una habilitat que tothom pot adquirir, amb pràctica, voluntat i constància. En tercer i últim lloc, el “com”, la metodologia adequada per presentar la poesia als infants. Aquest gènere literari s’ha de presentar de forma vivencial. El primer que han de fer els infants és estar en contacte amb la llengua i viure la poesia. Només així aprendran a estimar aquest gènere i a creure en ell i en les seves possibilitats.

Estratègies i metodologies per a la inclusió de l'alumnat nouvingut a les aules de parvulari

El propòsit d’aquesta recerca és analitzar i descriure les estratègies metodològiques que es porten als centres educatius de Catalunya per promoure la inclusió de l’alumnat nouvingut a les aules d’educació infantil. Durant els últims anys hi ha hagut un augment considerable de matriculacions dins i fora de termini d’alumnat procedent d’altres països. En conseqüència, les escoles han hagut d’assumir, amb més força que mai, el repte de la diversitat lingüística, cultural i social. Per analitzar aquesta qüestió en la present recerca, s’ha partit de la realitat de dues escoles catalanes amb alumnat de característiques molt diverses. Una escola amb un percentatge baix de nouvinguts, i l’altra, amb un percentatge molt elevat. Aquesta anàlisi de les experiències a les dues escoles catalanes s’ha centrat en l’observació i analitzar les estratègies metodològiques que s’emprenen a l’escola. Tot i que el present treball té com a centre l’educació infantil, donat que estic cursant aquest grau de mestre/a, la incorporació de l’alumnat nouvingut no pot deslligar-se dels plantejaments globals de centre. Per tant, la recerca no s’ha cenyit exclusivament a l’educació infantil sinó que també ha tingut en compte el conjunt d’accions també de l’educació primària i, molt especialment, una de les estratègies centrals en l’acollida d’infants nouvinguts com són les aules d’acollida. Aquestes vetllen per la inclusió de l’alumnat a l’aula ordinària, la cohesió social de tot l’alumnat i la igualtat d’oportunitats en el camí cap a l’educació intercultural basada en el respecte i coneixement de les diverses cultures presents a l’aula.

Performance of Poly-Carb, Inc. Flexogrid Bridge Overlay System, MLR-86-04, 2001

Intrusion of deicing materials and surface water into concrete bridge decks is a main contributor in deck reinforcing steel corrosion and concrete delamination. Salt, spread on bridge decks to melt ice, dissolves in water and permeates voids in the concrete deck. When the chloride content of the concrete in contact with reinforcing steel reaches a high enough concentration, the steel oxidizes. In Iowa, the method used to reduce bridge deck chloride penetration is the application of a low slump dense concrete overlay after the completion of all Class A and Class B floor repairs. A possible alternative to the use of dense concrete overlays, developed by Poly-Carb, Inc., is the MARK-163 FLEXOGRID Overlay System. FLEXOGRID is a two component system of epoxy and urethane which is applied on a bridge deck to a minimum thickness of ¼ inch. An aggregate mixture of silica quartz and aluminum oxide is broadcast onto the epoxy at a prescribed rate to provide deck protection and superior friction properties. The material is mixed on site and applied to the deck in a series of lifts (usually two) until the desired overlay thickness has been attained.

Laboratory Investigation of Concrete Beam-End Treatments, RB08-013, 2015

The ends of prestressed concrete beams under expansion joints are often exposed to moisture and chlorides. Left unprotected, the moisture and chlorides come in contact with the ends of the prestressing strands and/or the mild reinforcing, resulting in corrosion. Once deterioration begins, it progresses unless some process is employed to address it. Deterioration can lead to loss of bearing area and therefore a reduction in bridge capacity. Previous research has looked into the use of concrete coatings (silanes, epoxies, fiber-reinforced polymers, etc.) for protecting prestressed concrete beam ends but found that little to no laboratory research has been done related to the performance of these coatings in this specific type of application. The Iowa Department of Transportation (DOT) currently specifies coating the ends of exposed prestressed concrete beams with Sikagard 62 (a high-build, protective, solvent-free, epoxy coating) at the precast plant prior to installation on the bridge. However, no physical testing of Sikagard 62 in this application has been completed. In addition, the Iowa DOT continues to see deterioration in the prestressed concrete beam ends, even those treated with Sikagard 62. The goals of this project were to evaluate the performance of the Iowa DOT-specified beam-end coating as well as other concrete coating alternatives based on the American Association of State Highway and Transportation Officials (AASHTO) T259-80 chloride ion penetration test and to test their performance on in-service bridges throughout the duration of the project. In addition, alternative beam-end forming details were developed and evaluated for their potential to mitigate and/or eliminate the deterioration caused by corrosion of the prestressing strands on prestressed concrete beam ends used in bridges with expansion joints. The alternative beam-end details consisted of individual strand blockouts, an individual blockout for a cluster of strands, dual blockouts for two clusters of strands, and drilling out the strands after they are flush cut. The goal of all of the forming alternatives was to offset the ends of the prestressing strands from the end face of the beam and then cover them with a grout/concrete layer, thereby limiting or eliminating their exposure to moisture and chlorides.

De Novo Production of Metabolites by Fungal Co-culture of Trichophyton rubrum and Bionectria ochroleuca.

The co-cultivation of fungi has recently been described as a promising strategy to induce the production of novel metabolites through possible gene activation. A large screening of fungal co-cultures in solid media has identified an unusual long-distance growth inhibition between Trichophyton rubrum and Bionectria ochroleuca. To study metabolite induction in this particular fungal interaction, differential LC-MS-based metabolomics was performed on pure strain cultures and on their co-cultures. The comparison of the resulting fingerprints highlighted five de novo induced compounds, which were purified using software-oriented semipreparative HPLC-MS. One metabolite was successfully identified as 4″-hydroxysulfoxy-2,2″-dimethylthielavin P (a substituted trimer of 3,5-dimethylorsellinic acid). The nonsulfated form, as well as three other related compounds, were found in the pure strain culture of B. ochroleuca.