Environmental pollution promotes selection of microbial degradation pathways

Astonishing as it may seem, one organism's waste is often ideal food for another. Many waste products generated by human activities are routinely degraded by microorganisms under controlled conditions during waste-water treatment. Toxic pollutants resulting from inadvertent releases, such as oil spills, are also consumed by bacteria, the simplest organisms on Earth. Biodegradation of toxic or particularly persistent compounds, however, remains problematic. What has escaped the attention of many is that bacteria exposed to pollutants can adapt to them by mutating or acquiring degradative genes. These bacteria can proliferate in the environment as a result of the selection pressures created by pollutants. The positive outcome of selection pressure is that harmful compounds may eventually be broken down completely through biodegradation. The downside is that biodegradation may require extremely long periods of time. Although the adaptation process has been shown to be reproducible, it remains very difficult to predict.

Tratamiento de las úlceras neuropáticas con descargas

Las úlceras neuropáticas es una de las complicaciones que con más frecuencia presenta el paciente diabético. El principal objetivo en el tratamiento de las úlceras neuropáticas es potenciar los mecanismos fisiológicos de cicatrización, para ello es necesario actuar sobre los factores que retrasan este proceso. Uno de los principales factores que actúan como desencadenante y agravante en la aparición de una úlcera neuropática es el aumento de la presión plantar, condicionada por una alteración en el apoyo ya sea por causa estructural o biomecánica, al mismo tiempo esta hiperpresión continuada actúa retrasando los mecanismos de cicatrización. El método que ha demostrado mayor efectividad es el tratamiento de las úlceras neuropáticas plantares es el tratamiento con descargas. Vamos a exponer en este trabajo las diferentes técnicas de descarga que se pueden utilizar para tratar una ulcera neuropática a nivel ambulatorio.

Volcanic arcs fed by rapid pulsed fluid flow through subducting slabs

At subduction zones, oceanic lithosphere that has interacted with sea water is returned to the mantle, heats up during descent and releases fluids by devolatilization of hydrous minerals. Models for the formation of magmas feeding volcanoes above subduction zones require largescale transport of these fluids into overlying mantle wedges(1-3). Fluid flow also seems to be linked to seismicity in subducting slabs. However, the spatial and temporal scales of this fluid flow remain largely unknown, with suggested timescales ranging from tens to tens of thousands of years(3-5). Here we use the Li-Ca-Sr isotope systems to consider fluid sources and quantitatively constrain the duration of subduction-zone fluid release at similar to 70 km depth within subducting oceanic lithosphere, now exhumed in the Chinese Tianshan Mountains. Using lithium-diffusion modelling, we find that the wall-rock porosity adjacent to the flowpath of the fluids increased ten times above the background level. We show that fluids released by devolatilization travelled through the slab along major conduits in pulses with durations of about similar to 200 years. Thus, although the overall slab dehydration process is continuous over millions of years and over a wide range of pressures and temperatures, we conclude that the fluids produced by dehydration in subducting slabs are mobilized in short-lived, channelized fluid-flow events.

The Role of Magnesium in Concrete Deterioration, HR-355, 1994

Concretes with service lives of less than 15 years and those with lives greater than 40 years were studied with petrographic microscope, scanning electron microscope, and electron microprobe to determine why these two groups of concrete exhibit such different degrees of durability under highway conditions. Coarse aggregate used in both types of concrete were from dolomite rock, but investigation revealed that dolomite aggregate in the two groups of concretes were much different in several respects. The poorly-performing aggregate is fine-grained, has numerous euhedral and subhedral dolomite rhombohedra, and has relatively high porosity. Aggregate from durable concrete is coarse-grained, with tightly interlocked crystal fabric, anhedral dolomite boundaries, and low porosity. Aggregate in short service life concrete was found to have undergone pervasive chemical reactions with the cement which produced reaction rims on the boundaries of coarse aggregate particles and in the cement region adjacent to aggregate boundaries. Textural and porosity differences are believed to be chiefly responsible for different service lives of the two groups of concrete. The basic reaction that has occurred in the short service life concretes between coarse aggregate and cement is an alkali-dolomite reaction. In the reaction dolomite from the aggregate reacts with hydroxide ions from the cement to free magnesium ions and carbonate ions, and the magnesium ions precipitate as brucite, Mg(OH)2. Simultaneously with this reaction, a second reaction occurs in which product carbonate ions react with portlandite from the cement to form calcite and hydroxide ions. Crystal growth pressures of newly formed brucite and calcite together with other processes, e.g. hydration state changes of magnesium chloride hydrates, lead to expansion of the concretes with resultant rapid deterioration. According to this model, magnesium from any source, either from reacting dolomite or from magnesium road deicers, has a major role in highway concrete deterioration. Consequently, magnesium deicers should be used with caution, and long-term testing of the effects of magnesium deicers on highway concrete should be implemented to determine their effects on durability.

Alternativas del moldeado en alteraciones del antepié

El molde en carga controlada sobre espumas de poliuretano es la técnica de moldeado que mejores resultados nos está ofreciendo en la actualidad, ya que permite la obtención del molde en posición más fisiológica, con el paciente en bipedestación en ángulo y base de marcha, permitiendo la distensión de tejidos blandos evitando riesgo de hipercorrecciones, además de poder realizarlo sobre un banco de marcha informatizado permitiendo visualizar a través del monitor la huella plantar simultáneamente a la confección de dicho molde. La importancia de la realización de tratamientos ortopodológicos individualizados o personalizados en función de cada patología, nos ha conducido a realizar también el molde de forma personalizada en función del diagnóstico obtenido. Para ello hemos descrito una técnica modificada del molde en carga controlada aplicando el sistema diagnóstico "Functional block test" en su confección. El sistema diagnóstico "block test", descrito por el Doctor Whitney de la Temple University de Philadelphia, es de gran utilidad en laexploración clínica diaria. Se basa en el diseño de diferentes cuñas o elementos compensadores de cada patología existente en el pie en cada uno de los tres planos corporales. La aplicación del elemento correspondiente a la patología situado bajo el pie con el paciente en blpedestación conduce a la articulación subastragalina hacia su neutralidad y por tanto ayuda a confirmar el diagnóstico obtenido. La aplicación de dichos elementos en la confección del molde en carga permite un mejor control de la posición neutra del pie y un óptimo reflejo de dicha patología en el molde confeccionado, permitiendo posteriormente su correcta compensación en el tratamiento ortopodológico..

Efecto de las ortesis plantares en los cambios de presión del antepié

El uso de soportes plantares ante la presenda de sobrecargas metatarsales se ha mostrado como un tratamiento muy efectivo ante la sintomatología dolorosa asociada a esta problemática del antepié, secundariaprincipalmente a problemas biomecánicos. Este estudio trata de demostrar la justificación del efecto de estos tratamientos, mediante el análisis de los cambios de presión que suceden en el antepié con el uso de un soporte plantar prefabricado y otro confeccionado a medida. Los resultados ofrecen cambios significativos con el uso de los tratamientos ortopodológicos, principalmente con los individualizados, es decir, los confeccionados a medida sobre un molde del pie.

Tratamiento combinado en un pie cavo varo bilateral

Paciente femenina de 34 años de edad, acude a la consulta con dolor agudo selectivo en la zona plantar del antepie a nivel de las cabezas del 1er y 2º metatarsiano. Realizada la anamnesis descartamos cualquier posibilidad de traumatismo o neuralgia. A lo largo de este trabajo expondremos las características principales de la paciente observadas durante la exploración tanto en estática como en dinámica, diseño del plan de tratamiento con los objetivos que pretendemos alcanzar, metodología de aplicación y conclusiones.

El escafoides accesorio y su relación con el pie valgo-plano

Se estudia la patología dolorosa, que en ocasiones, puede producir la existencia de un escafoides accesorio del tarso. Este hueso accesorio generalmente se une al escafoides con la maduración ósea, hacia la adolescencia, mediante un centro secundario de osificación, En ocasiones se vuelve doloroso cuando, en esta edad, existe un exceso de tracción del tendón del tibial posterior, el cual se inserta en este centro secundario de sificación; esto puede ser producido por la presencia de un pie valgo-plano o por la realización de una fuerte actividad física. También, aquellos accesorios que son muy prominentes, pueden volverse sintomáticos con el roce con el calzado. Inicialmente el tratamiento será conservador, evitando el exceso de tracción del tendón del tibial posterior mediante reposo, y con la utilización de un soporte plantar que disminuya la pronación del pie. Esperando la osificación de ambos huesos, en la gran mayoría de las veces desaparecen los síntomas. Solamente en algunos casos es necesaria la intervención quirúrgica, la cual consiste en la simple exéresis del accesorio. En éste artículo se desmiente, de forma argumentada, la hipótesis de que el escafoides accesorio produce un pie valgo-plano. No obstante, si se constata la importante asociación que hay entre su existencia cuando es sintomático y el aplanamiento del pie; la explicación que se da a esto es que, cuando hay un pie plano, el exceso de pronación que este ocasiona provocará un exceso de tracción del tendón del tibial posterior sobre el accesorio,convirtiéndolo en doloroso; éstos son los pies que vienen a la consulta, y no los asintomáticos, dando la falsa impresión de que el escafoides accesorio provoca un pie valgo-plano.

Parálisis cerebral. Tratamiento ortopodológico

Después de varios años de experiencia en la aplicación de las férulas estabilizadoras del sistema aquileocalcáneo plantar FESAP) en pacientes con parálisis cerebral, creemos que deberían ser el tratamiento ortopodológico de elección del pie equino en niños con miopatías y lesiones neurológlcas de la unidad motora, del sistema piramidal o extrapiramidal, tanto por su perfecta adaptación a la morfología de la extremidad inferior como por sus caracteristicas funcionales y sus acciones fisio1ógicas y terapéuticas.

Structure and kinematics of the Jungfrau syncline, Faflertal (Valais, Alps), and its regional significance

The formation and structural evolution of the jungrau syncline is described, based on excellent outcrops occurring in the lotschental, in the central alps of switzerland. the quality of the outcrops allows us to demonstrate that the external massifs of the swiss alps have developed due to internal folding. The jungfrau suncline, which separates the autochtonous gastern dome from the aar massif basement gneiss folds, is composed of slivers of basement rocks with their mesozoic sedimentary cover. in the inner faflertal, a side valley of the lotschental, the 200 m thick syncline cp, roses fpir imots, the gastern massif with a reduced mesozoic sedimentary cover in a normal stratigraphic succession, two units of overturned basement rocks with their mesozoic sedimentary cover, and the overturned lower limn of the tschingelhorn gneiss fold of the aar massif with lenses of its sedimentary cover. stratigraphy shows that the lower units, related to the gastern massis, are condensed and that the upper units, deposited farther away from a gastern paleo-high, form a more complete sequence, linked to the doldenhorn meso-cneozoic basin fill. the integration of these local observations with published regional data leads to the following model. on the northern margin of the doldenhorn hbasin, at the northern fringe of the alpine tethuys, the pre-triassic crystalline basement and its mesozoic sedimentary cover were folded by ductile deformation at temperatures above 300 degrees C and in the presence of high fluid pressures, as the helveti c and penninic nappes were overthrusted towards the northwest during the main alpine deformation phase, the visosity contrast between the basement gneisses and the sediments caused the formation of large basement anticlines and tight sedimentary sunclines (mullion-type structures). The edges of basement blocks bounded buy pre-cursor se-dipping normal faults at the northwestern border of the doldenhorn basin were deformed bu simple shear, creating overturned slices of crystalline rocks with their sedimentary cover in what now forms the hungfrau syncline. the localisation of ductile deformation in the vicinity of pre-existing se-dipping faults is thought to have been helped by the circulation of fluids along the faults; these fluids would have been released from the mesozoic sediments by metamorphic dehydration reactions accompanied by creep and dynamic recrystallisation of quartz at temperatures above 300 degrees C. Quantification of the deformation suggests an strain ellipsoid with a ratio (1 + e(1)/+ e(3)) of approximately 1000. The jungfrau suncline was deformed bu more brittle nw-directed shear creating well-developed shear band cleavages at a late stage, after cooling by uplift and erosion. It is suggested that the external massifs of the apls are basement gneiss folds created at temperatures of 300 degrees C by detachment through ductile deformation of the upper crust of the european plate as it was underthrusted below the adriatic plate.

Combination of bevacizumab and 2-weekly pegylated liposomal doxorubicin as first-line therapy for locally recurrent or metastatic breast cancer. A multicenter, single-arm phase II trial (SAKK 24/06).

BACKGROUND: Pegylated liposomal doxorubicin (PLD) and bevacizumab are active agents in the treatment of metastatic breast cancer (MBC). We carried out a multicenter, single-arm phase II trial to evaluate the toxicity and efficacy of PLD and bevacizumab as first-line treatment in MBC patients. METHODS: Bevacizumab (10 mg/kg) and PLD (20 mg/m(2)) were infused on days 1 and 15 of a 4-week cycle for a maximum of six cycles. Thereafter, bevacizumab monotherapy was continued at the same dose until progression or toxicity. The primary objective was safety and tolerability, and the secondary objective was to evaluate efficacy of the combination. RESULTS: Thirty-nine of 43 patients were assessable for the primary end point. Eighteen of 39 patients (46%, 95% confidence interval 30% to 63%) had a grade 3 toxicity. Sixteen (41%) had grade 3 palmar-plantar erythrodysesthesia, one had grade 3 mucositis, and one severe cardiotoxicity. Secondary end point of overall response rate among 43 assessable patients was 21%. CONCLUSIONS: In this nonrandomized single-arm trial, the combination of bimonthly PLD and bevacizumab in locally recurrent and MBC patients demonstrated higher than anticipated toxicity while exhibiting only modest activity. Based on these results, we would not consider this combination for further investigation in this setting.

Natural selection on fecundity variance in subdivided populations: kin selection meets bet hedging.

In a series of seminal articles in 1974, 1975, and 1977, J. H. Gillespie challenged the notion that the "fittest" individuals are those that produce on average the highest number of offspring. He showed that in small populations, the variance in fecundity can determine fitness as much as mean fecundity. One likely reason why Gillespie's concept of within-generation bet hedging has been largely ignored is the general consensus that natural populations are of large size. As a consequence, essentially no work has investigated the role of the fecundity variance on the evolutionary stable state of life-history strategies. While typically large, natural populations also tend to be subdivided in local demes connected by migration. Here, we integrate Gillespie's measure of selection for within-generation bet hedging into the inclusive fitness and game theoretic measure of selection for structured populations. The resulting framework demonstrates that selection against high variance in offspring number is a potent force in large, but structured populations. More generally, the results highlight that variance in offspring number will directly affect various life-history strategies, especially those involving kin interaction. The selective pressures on three key traits are directly investigated here, namely within-generation bet hedging, helping behaviors, and the evolutionary stable dispersal rate. The evolutionary dynamics of all three traits are markedly affected by variance in offspring number, although to a different extent and under different demographic conditions.

Validation of Design Recommendations for Integral Abutment Piles, HR-292, 1989

Since integral abutment bridges decrease the initial and maintenance costs of bridges, they provide an attractive alternative for bridge designers. The objective of this project is to develop rational and experimentally verified design recommendations for these bridges. Field testing consisted of instrumenting two bridges in Iowa to monitor air and bridge temperatures, bridge displacements, and pile strains. Core samples were also collected to determine coefficients of thermal expansion for the two bridges. Design values for the coefficient of thermal expansion of concrete are recommended, as well as revised temperature ranges for the deck and girders of steel and concrete bridges. A girder extension model is developed to predict the longitudinal bridge displacements caused by changing bridge temperatures. Abutment rotations and passive soil pressures behind the abutment were neglected. The model is subdivided into segments that have uniform temperatures, coefficients of expansion, and moduli of elasticity. Weak axis pile strains were predicted using a fixed-head model. The pile is idealized as an equivalent cantilever with a length determined by the surrounding soil conditions and pile properties. Both the girder extension model and the fixed-head model are conservative for design purposes. A longitudinal frame model is developed to account for abutment rotations. The frame model better predicts both the longitudinal displacement and weak axis pile strains than do the simpler models. A lateral frame model is presented to predict the lateral motion of skewed bridges and the associated strong axis pile strains. Full passive soil pressure is assumed on the abutment face. Two alternatives for the pile design are presented. Alternative One is the more conservative and includes thermally induced stresses. Alternative Two neglects thermally induced stresses but allows for the partial formation of plastic hinges (inelastic redistribution of forces). Ductility criteria are presented for this alternative. Both alternatives are illustrated in a design example.

A Variscan pressure-temperature-time path for the N-E Mont Blanc massif

The northeastern portion of the Mont Blanc massif in western Switzerland is predominantly comprised of the granitic rocks of the Mont Blanc intrusive suit, and the Mont Blanc basement gneisses. Within these metamorphic rocks are a variety of sub-economic Fe skarns. The mineral assemblages and fluid inclusions from these rocks have been used to derive age, pressure, temperature and fluid composition constraints for two Variscan events. Metamorphic hornblendes within the assemblages from the basement amphibolites and iron sk:lms have been dated using Ar-40/Ar-39, and indicate that these metamorphic events have a minimum age of approximately 334 Ma. Garnet-hornblende-plagioclase thermobarometry and stable isotope data obtained from the basement amphibolites are consistent with metamorphic temperatures in the range 515 to 580 degrees C, and pressures ranging from 5 to 8 kbar. Garnet-hornblende-magnetite thermobarometry and fluid inclusion studies indicate that the iron skarns formed at slightly lower temperatures, ranging from 400 to 500 degrees C in the presence of saline fluids at formational pressures similar to those experienced by the basement amphibolites. Late Paleozoic minimum uplift rates and geothermal gradients calculated using these data and the presence of Ladinien ichnofossils are on the order of 0.32 mm/year and 20 degrees C/km respectively. These uplift rates and geothermal gradients differ from those obtained from the neighbouring Aiguilles Rouges massif and indicate that these two massifs experienced different metamorphic conditions during the Carboniferous and Permian periods. During the early to late Carboniferous period the relative depths of the two massifs were reversed with the Aiguilles Rouges being initially unroofed at a much greater rate than the Mont Blanc, but experiencing relatively slower uplift rates near the termination of the Variscan orogeny.

Parallel evolution of facial stripe patterns in the Neolamprologus brichardi/pulcher species complex endemic to Lake Tanganyika.

Colour pattern diversity can be due to random processes or to natural or sexual selection. Consequently, similarities in colour patterns are not always correlated with common ancestry, but may result from convergent evolution under shared selection pressures or drift. Neolamprologus brichardi and Neolamprologus pulcher have been described as two distinct species based on differences in the arrangement of two dark bars on the operculum. Our study uses DNA sequences of the mitochondrial control region to show that relatedness of haplotypes disagrees with species assignment based on head colour pattern. This suggests repeated parallel evolution of particular stripe patterns. The complete lack of shared haplotypes between populations of the same or different phenotypes reflects strong philopatric behaviour, possibly induced by the cooperative breeding mode in which offspring remain in their natal territory and serve as helpers until they disperse to nearby territories or take over a breeding position. Concordant phylogeographic patterns between N. brichardi/N. pulcher populations and other rock-dwelling cichlids suggest that the same colonization routes have been taken by sympatric species and that these routes were affected by lake level fluctuations in the past.