Photocatalytic fixation of NOx in soils.

Nitrogen oxides (NOx = NO + NO2) are important atmospheric pollutants that are directly harmful to human health. Recently in urban and industrial areas, synthetic materials have been developed and deployed to photocatalytically oxidize NOx to nitrate (NO3-) in order to improve air quality. We show that the natural presence of small amounts (≤5%) of titanium oxides, such as anatase and rutile, can also drive NOx oxidation to nitrate in soils under UV-visible irradiation. The NO uptake coefficients ranged between 0.1 × 10-6 for sandy soils to 6.4 × 10-5 in the case of tropical clay soils; the latter comparable in efficiency to current industrial man-made catalysts. This photocatalytic N-fixation mechanism offers a new strategy for NOx mitigation from the atmosphere by transforming it into nitrate, and simultaneously provides an energy efficient source of essential fertilizer to agriculture.

Cobalt containing glass fibres and their synergistic effect on the HIF-1 pathway for wound healing applications.

Introduction and Methods: Chronic wounds are a major healthcare problem, but their healing may be improved by developing biomaterials which can stimulate angiogenesis, e.g. by activating the Hypoxia Inducible Factor (HIF) pathway. Here, novel glass fibres were produced by laser spinning. The hypothesis was that silicate glass fibres that deliver cobalt ions will activate the HIF pathway and promote the expression of angiogenic genes. The glass composition was designed to biodegrade and release ions, but not form a hydroxyapatite layer in body fluid. Results and Discussion: Dissolution studies demonstrated that hydroxyapatite did not form. When keratinocyte cells were exposed to conditioned media from the cobalt-containing glass fibres, significantly higher amounts of HIF-1α and Vascular Endothelial Growth Factor (VEGF) were measured compared to when the cells were exposed to media with equivalent amounts of cobalt chloride. This was attributed to a synergistic effect of the combination of cobalt and other therapeutic ions released from the glass. The effect was also much greater than the sum of HIF-1α and VEGF expression when the cells were cultured with cobalt ions and with dissolution products from the Co-free glass, and was proven to not be due to a rise in pH. The ability of the glass fibres to activate the HIF-1 pathway and promote VEGF expression shows the potential for their use in chronic wound dressings.

Resilience of ecosystem service delivery in grasslands in response to single and compound extreme weather events.

Extreme weather events are increasing in frequency and magnitude with profound effects on ecosystem functioning. Further, there is now a greater likelihood that multiple extreme events are occurring within a single year. Here we investigated the effect of a single drought, flood or compound (flood + drought) extreme event on temperate grassland ecosystem processes in a field experiment. To assess system resistance and resilience, we studied changes in a wide range of above- and below-ground indicators (plant diversity and productivity, greenhouse gas emissions, soil chemical, physical and biological metrics) during the 8 week stress events and then for 2 years post-stress. We hypothesized that agricultural grasslands would have different degrees of resistance and resilience to flood and drought stress. We also investigated two alternative hypotheses that the combined flood + drought treatment would either, (A) promote ecosystem resilience through more rapid recovery of soil moisture conditions or (B) exacerbate the impact of the single flood or drought event. Our results showed that flooding had a much greater effect than drought on ecosystem processes and that the grassland was more resistant and resilient to drought than to flood. The immediate impact of flooding on all indicators was negative, especially for those related to production, and climate and water regulation. Flooding stress caused pronounced and persistent shifts in soil microbial and plant communities with large implications for nutrient cycling and long-term ecosystem function. The compound flood + drought treatment failed to show a more severe impact than the single extreme events. Rather, there was an indication of quicker recovery of soil and microbial parameters suggesting greater resilience in line with hypothesis (A). This study clearly reveals that contrasting extreme weather events differentially affect grassland ecosystem function but that concurrent events of a contrasting nature may promote ecosystem resilience to future stress.

Photochemical emission and fixation of NOX gases in soils.

Gaseous nitrogen oxides (NOx), which result from the combustion of fossil fuels, volcanic eruptions, forest fires, and biological reactions in soils, not only affect air quality and the atmospheric concentration of ozone, but also contribute to global warming and acid rain. Soil NOx emissions have been largely ascribed to soil microbiological processes; but there is no proof of abiotic catalytic activity affecting soil NO emissions. We provide evidence of gas exchange in soils involving emissions of NOx by photochemical reactions, and their counterpart fixation through photocatalytic reactions under UV-visible irradiation. The catalytic activity promoting NOx capture as nitrate varied widely amongst different soil types, from low in quartzitic sandy soils to high in iron oxide and TiO2 rich soils. Clay soils with significant amounts of smectite also exhibited high rates of NOx sequestration and fixed amounts of N comparable to that of NO (nitric oxide) losses through biotic reactions. In these soils, a flux of 100 µg NNO m-2 h-1, as usually found in most ecosystems, could be reduced by these photochemical reactions by more than 60%. This mechanism of N fixation provides new insight into the nitrogen cycle and may inspire alternative strategies to reduce NO emissions from soils.

OPTIMAL ENTERPRISE RESULTS IN THE CLINICAL RESEARCH ENVIRONMENT.

Even the best scientific minds cannot repeatedly produce desired results when working in sub-optimal systems. Complex enterprises are difficult to understand and manage. Cause-and-effect relationships are often separated in time and space, making real improvements challenging. To understand how complex systems work it is essential that we employ tools that accurately map and quantify the dynamics that drive results. Computer modeling and simulation (CMAS) is a valuable design, planning, management, and overall analytical decision-support tool to achieve effective and efficient results. CMAS could become a ubiquitous tool in the lengthy and complex environment of the clinical research (CR) enterprise. Without the comprehensive understanding gained when applying CMAS, organizations may continue to be overwhelmed by problems such as unnecessary bottlenecks, high costs, low productivity, and the inability of retaining critical staff. The approach explained here may complement or even replace traditional methods when organizations pursue greater enterprise capability.

Crop residues exacerbate the negative effects of extreme flooding on soil quality.

Extreme flood events are predicted to have a negative impact on soil quality. Currently, there is a lack of information about the effect of agricultural practices on soil functioning and microbial processes under these events. We hypothesized that the impact of flooding on soil quality will be exacerbated when crop residues are present in the soil as they will induce more extreme anaerobicity. A spring extreme flood event (10 °C, 9 weeks) was simulated in mesocosms containing an arable sandy-loam soil low in nutrients. The main treatments were (1) with and without flooding and (2) with and without maize residue addition (8 Mg ha-1). We monitored changes in soil chemical quality indicators (e.g. pH, salinity, Fe3+, P, C, NH4 +, NO3 - and organic N), greenhouse gas (GHG) emissions (CO2, CH4, N2O) and soil microbial community composition (PLFAs) during a prolonged flood period (9 weeks) and an 8-week "recovery" period after flooding. In comparison to the other treatments, flooding in the presence of crop residues resulted in a dramatic drop in soil redox potential. This was associated with the enhanced release of Fe and C into solution and an increase in CH4 emissions. In contrast, maize residues reduced potential nitrate losses and N2O emissions, possibly due to complete denitrification and microbial N immobilization. Both flooding and maize residues stimulated microbial growth and promoted a shift in microbial community composition. Following floodwater removal, most of the soil quality indicators returned to the levels of the control treatment within 5 weeks. After this short recovery phase, no major impact of flooding could be observed on plant growth (maize pot-grown). Overall, we conclude that both extreme flooding and management regime negatively impact upon a range of soil quality indicators (e.g. redox, GHG emissions); however, the soil showed high resilience and recovered quickly after floodwater removal. Further work is required to investigate the impact of repeated extreme flood events on soil quality and function over longer timescales.

Tumor de células gigantes. Presentación de un caso / Giant-cell tumor. Case Report

El Tumor de Células Gigantes, es una patología poco frecuente, actualmente es considerado como una Neoplasia Benigna, con potencial maligno, localmente agresiva y con tendencia a la recidiva. Aparece generaralmente en la tercera o cuarta décadas de la vida, teniendo predilección por la epífisis de los huesos largos en especial por el tercio distal del fémur, proximal de la tibia y distal del radio . En este informe se trata de un paciente que acude a Nuestro Hospital presentando molestias en rodilla izquierda, discreta limitación a la movilidad y dolor que ha ido incrementándose; por lo que es ingresado y luego de realizársele exámenes de Laboratorio y Radiología, se diagnostica un Tumor de Células Gigantes, el cual es intervenido quirúrgicamente, practicándose Reseccion en Bloque de la Masa Tumoral con Curetaje Óseo y Auto injerto Óseo de Cresta Iliaca. (AU)

Tumor de células gigantes: presentación de un caso / Giant-cell tumor: case report

El Tumor de Células Gigantes, es una patología poco frecuente, actualmente es considerado como una Neoplasia Benigna, con potencial maligno, localmente agresiva y con tendencia a la recidiva. Aparece generaralmente en la tercera o cuarta décadas de la vida, teniendo predilección por la epífisis de los huesos largos en especial por el tercio distal del fémur, proximal de la tibia y distal del radio . En este informe se trata de un paciente que acude a Nuestro Hospital presentando molestias en rodilla izquierda, discreta limitación a la movilidad y dolor que ha ido incrementándose; por lo que es ingresado y luego de realizársele exámenes de Laboratorio y Radiología, se diagnostica un Tumor de Células Gigantes, el cual es intervenido quirúrgicamente, practicándose Reseccion en Bloque de la Masa Tumoral con Curetaje Óseo y Auto injerto Óseo de Cresta Iliaca.

Giant-cell tumor is an uncommon pathology, currently considered as a benign neoplasm with highly malignant potential, locally agressive and tending to relapse. It may fenerally develop diuring the third or fourth decades of life. It occurs at the epiphysis of long bones esp. distal to the femur, proximal to the tibia and distal to the radius. This is the report of a patients who comes to our Hospital for injury in his left knee, some limitation as to mobility and increasing pain. He was admitted to hospital and had some lab test done as well as radiologic imagin. A giant-cell tumor is diagnosed, which is surgically removed. Recection in bloque was the surgical procedure used to remove the mass with osseous curettage and osseous graft of the Iliac crest.