405 research outputs found
Hydra tropomyosin TROP1 is expressed in head-specific epithelial cells and is a major component of the cytoskeletal structure that anchors nematocytes
A cDNA clone encoding a 253 amino acid tropomyosin was
isolated from
Hydra in a differential screen for headspecific
genes. The Hydra tropomyosin gene, designated
trop1, is a single copy gene, lacks introns and is strongly
expressed in tentacle-specific epithelial cells. Analysis of
protein synthesis in head and gastric tissue indicated a high
rate of tropomyosin synthesis in head tissue. Immunolocalization
of tropomyosin in tentacle tissue revealed a
cushion-like tropomyosin-containing structure within
battery cells at the base of nematocytes. The structure
appears to form part of the cytoskeletal anchor for nematocytes.
Tropomyosin cushions were also observed in
epithelial cells along the body column, which contain
mounted stenotele nematocytes
Optimal management of the Jucar River and Turia River basins under uncertain drought conditions
This paper presents a methodology to assess the best behavior achievable for a water resources system, and we apply it to the joint system of the Jucar River and Turia River basins in Spain. The resources of the two rivers are used jointly to meet the different water uses within the region, especially urban demands and environmental requirements. The climate change effects in this area are predicted to be particularly severe in this area with great variability in drought patterns. The results are particularly suitable for evaluating the best performance of the system under uncertain conditions
Assessing future drought risks and wheat yield losses in England
Acknowledgement: The authors acknowledge the Class Stiftung Foundation their financial support, Cambridge NIAB for solar radiation data, Cranfield Soil and Agrifood Institute for the soil characteristics data, AHDB for access to their Recommended List Trial yield data. We are grateful for access to the UK Meteorological Office MIDAS Land Surface Stations data (1853-current) from the British Atmospheric Data Centre (http://badc.nerc.ac.uk/data/ukmo-midas). Rothamsted Research receives grant-aided support from the Biotechnology and Biological Sciences Research Council through Designing Future Wheat [BB/P016855/1] and Achieving Sustainable Agricultural Systems [NE/N018125/1].Peer reviewedPublisher PD
Aprenentatge 2.0
[p.4] Escola 2.0[p.8] Aprenentatge digital: oportunitats i conflictes[p.14] La cara oculta de la tecnologia[p.16] La Fortuna dels Commons[p.22] "El Coneixement us farà lliures"[p.28] Salvant la Terra amb el teclat[p.34] De l’educació a l’aprenentatgePeer Reviewe
Interacciones montaña-llanura frente al cambio global: desafíos y oportunidades en la gestión del territorio y de los recursos hídricos en Riegos del Alto Aragón
The transformation of rainfed agriculture lands into irrigated lands in the central sector of the Ebro Depression has represented a spectacular change in the cultivation conditions of a semi-arid territory affected by scarce and irregular precipitation. However, the new irrigation systems faced serious structural problems from the beginning due to the peculiar design of the irrigation system, the limitations of its objectives, the slow pace with which the infrastructures were built (reservoirs, canals and secondary ditches) and the conditioning of cultivated fields. This work focuses on the study of the limitations faced by Riegos del Alto Aragón due to the trend shown by water resources and their seasonal distribution as a result of the evolution of temperature and precipitation, the expansion of woody vegetation in mountain areas and the progressive silting up of the reservoirs. For this, the information available on Global Change in the Pyrenees has been reviewed and climatic and hydrological models have been applied. The necessary modernization has improved the irrigation systems and water use efficiency, and has allowed the expansion of much more productive and profitable crops. Paradoxically, modernization has also increased the water demand, and has made necessary to increase the system’s internal reserves through the construction of small reservoirs and ponds. This greater water demand coincides with a decreasing trend in water resources availability, due not only to the increase in average temperature, but also to changes in snowpack accumulation and melting dynamics in the Pyrenean headwaters and to forest expansion in old abandoned fields in the Pyrenean valleys, which reduces runoff generation and streamflow. It is foreseeable that most of these processes will continue or even accentuate in the medium- to long-term due to climate change. In addition, the progressive silting up of the reservoirs reduces the water storage capacity year after year. These processes, which highlight the interactions between mountain areas and the lowlands, will force in the medium term to reorganize the management of resources and irrigation procedures, as well as the progressive incorporation of crops with increasing added value that offset the rise in production costs linked to a stronger dependence of irrigation with respect to energy.La transformación del secano en regadío en el sector central de la Depresión del Ebro ha representado un cambio espectacular en las condiciones de cultivo de un territorio de características semiáridas y precipitaciones muy irregulares. Sin embargo, los nuevos regadíos se enfrentaron desde un principio a graves problemas estructurales debido al peculiar diseño del sistema de regadío, las limitaciones de sus objetivos, la lentitud con que se fueron construyendo las infraestructuras necesarias (embalses, canales y acequias secundarias) y el acondicionamiento de los campos de cultivo. Este trabajo se centra en el estudio de las limitaciones a que se enfrentan los regadíos de Riegos del Alto Aragón (R.A.A.) debido a la tendencia que muestran los recursos hídricos y su distribución estacional como consecuencia de la evolución de temperaturas y precipitaciones, la expansión de la superficie forestal y de matorrales en áreas de montaña y el progresivo aterramiento a que se enfrentan los embalses. Para ello se ha revisado la información disponible sobre el Cambio Global en el Pirineo y se han aplicado diversos modelos climáticos e hidrológicos. La necesaria modernización ha mejorado los sistemas de riego, ha incrementado la eficiencia en el uso de los recursos hídricos, y ha permitido la introducción de nuevos cultivos mucho más productivos y rentables. Paradójicamente, la modernización también ha conllevado un aumento del consumo de agua y ha obligado a incrementar las reservas internas del sistema mediante la construcción de pequeños embalses y balsas. Esta mayor demanda de agua coincide con una progresiva reducción en la disponibilidad de recursos hídricos, debida no solo al incremento de la temperatura media sino también a los cambios en la dinámica de la acumulación y fusión de nieve en alta montaña y a la expansión de bosques y matorrales en antiguos campos de cultivo abandonados en los valles pirenaicos, lo que reduce la capacidad de generación de escorrentía y los caudales fluviales. Se prevé que estas tendencias se acentúen en el medio y largo plazo como consecuencia del cambio climático. Además, el progresivo aterramiento de los embalses reduce año tras año la capacidad de almacenamiento de agua. Estos procesos, que ponen de manifiesto la importancia de las interacciones entre las áreas de montaña y las regiones de piedemonte, obligarán a medio plazo a reorganizar la gestión de los recursos y de los procedimientos de regadío, así como la progresiva incorporación de cultivos de mayor valor añadido que compensen el incremento de los costes de producción ligados a una mayor dependencia de los regadíos respecto de la energía
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A phase II study of temsirolimus and liposomal doxorubicin for patients with recurrent and refractory bone and soft tissue sarcomas
Background
Relapsed and refractory sarcomas continue to have poor survival rates. The cancer stem cell (CSC) theory provides a tractable explanation for the observation that recurrences occur despite dramatic responses to upfront chemotherapy. Preclinical studies demonstrated that inhibition of the mechanistic target of rapamycin (mTOR) sensitizes the CSC population to chemotherapy.
Methods
Here we present the results of the Phase II portion of a Phase I/II clinical trial that aimed to overcome the chemoresistance of sarcoma CSC by combining the mTOR inhibitor temsirolimus (20 mg/m2 weekly) with the chemotherapeutic agent liposomal doxorubicin (30 mg/m2 monthly).
Results
Fifteen patients with relapsed/refractory sarcoma were evaluable at this recommended Phase 2 dose level. The median progression free survival was 315 days (range 27–799). Response rate, defined as stable disease or better for 60 days, was 53%. Nine of the patients had been previously treated with doxorubicin. Therapy was well tolerated. In a small number of patients, pre- and post- treatment tumor biopsies were available for assessment of ALDH expression as a marker of CSCs and showed a correlation between response and decreased ALDH expression. We also found a correlation between biopsy-proven inhibition of mTOR and response.
Conclusions
Our study adds to the literature supporting the addition of mTOR inhibition to chemotherapy agents for the treatment of sarcomas, and proposes that a mechanism by which mTOR inhibition enhances the efficacy of chemotherapy may be through sensitizing the chemoresistant CSC population. Further study, ideally with pre- and post-therapy assessment of ALDH expression in tumor cells, is warranted.
Trial registration The trial was registered on clinicaltrials.gov (NCT00949325) on 30 July 2009. http://www.editorialmanager.com/csrj/default.asp
Effect of an early neurocognitive rehabilitation on autonomic nervous system in critically ill patients
Introduction
Recent clinical and electrophysiological studies reveal a high incidence of autonomic nervous system (ANS) dys- function in patients treated in ICU [1]. ANS disturbances may produce diverse and unexpected consequences. For instance, critically ill patients are at risk of neurocognitive impairments that may persist after hospital discharge. Among various pathophysiological mechanisms proposed, ANS dysfunction leading cholinergic deficiency seems one of the most viable to explain the development of long-term sequelae. Heart rate variability (HRV) has been related to the activity of the prefrontal cortex [2] hence, prefrontal activation could help to strengthen the auto- nomic nervous system integrity. We are interested in assessing the improvement of the ANS dysfunction through neural circuits’ activation. Thus, we propose a novel therapy that could allow the reinforcing of ANS through an early neurocognitive intervention targeted to improve prefrontal activation.
Objectives
The aim of this study was to explore if the integrity of the ANS, via cardiac vagal tone, measured by the HRV can be modified after early neurocognitive rehabilitation in ICU patients.
Methods
A total of 17 critically ill patients received a 20-minute Early Neurocognitive Rehabilitation (ENR) session in their own bed in the ICU. HRV was derived from the recorded ECG signal during pre-session, session and post-session. Power in the specific frequency bands related to sympathetic and parasympathetic systems was computed (PLF and PHF for low and high frequency bands, respectively). PLF was computed within the clas- sic band, while PHF was computed within a band cen- tered at respiratory rate. Changes in the HRV parameters from pre-session to session, and from pre- session to post-session were studied using Wilcoxon signed-rank test.
Results
Clinical data of the sample are summarized in table 1. Comparing with baseline values, 9 patients (53%) showed a decreased PLF in post-session, while 8 patients (47%) presented a higher PLF (p = .759). In 12 patients (71%), PHF increased after the ENR session, suggesting an increase of parasympathetic activity (p = .836).
Conclusions
Diagnosis, severity of illness or medication could explain the differential effect in the evolution of the HRV para- meters among different patients. Despite differences, an early neurocognitive rehabilitation seems to increase parasympathetic activity after the session in the majority of the patients. Clinical characteristics of the critical ill patients should be further studied to determinate which patients could be the best candidates for early neurocog- nitive intervention
Aspergillus Niger QH27 in the Removal of Toxic Dyes: Biosorption of Eriochrome Black T Under Various Experimental Conditions
Water pollution by toxic dyes such as Eriochrome Black T (EBT) is an increasing environmental issue, and the use of biosorbents represents a sustainable alternative for their treatment. In this study, the ability of Aspergillus niger QH27 fungal biomass in removing EBT under various experimental conditions was investigated. The main objective was to evaluate biosorption efficiency and determine the optimal conditions for dye removal. The methodology consisted of performing experiments by varying pH (5, 7 and 9) and agitation speed (100, 150 and 200 rpm), and analysing dye removal efficiency and adsorption capacity. Results showed that EBT removal was most effective at low pH values and higher agitation speeds. At a pH of 5 and agitation of 200 rpm, the maximum removal efficiency (99.17 %) and adsorption capacity (1.24 mg/g) were achieved. Fourier transform infrared spectroscopy (FTIR) analyses were carried out to examine the changes in functional groups of fungal biomass before and after EBT biosorption. FTIR results suggested the active involvement of these groups in the dye removal process. In conclusion, Aspergillus niger QH27 biomass proved to be an efficient biosorbent for the removal of EBT dye in aqueous solutions. This study provides valuable information for the development of sustainable and low-cost strategies in treating wastewater contaminated with dyes and expands the knowledge of dye biosorption using fungal biomass
On Field Theory Thermalization from Gravitational Collapse
Motivated by its field theory interpretation, we study gravitational collapse
of a minimally coupled massless scalar field in Einstein gravity with a
negative cosmological constant. After demonstrating the accuracy of the
numerical algorithm for the questions we are interested in, we investigate
various aspects of the apparent horizon formation. In particular, we study the
time and radius of the apparent horizon formed as functions of the initial
Gaussian profile for the scalar field. We comment on several aspects of the
dual field theory picture.Comment: 31 pages, 17 figures; V2 Some figures corrected, minor revision.
arXiv admin note: substantial text overlap with arXiv:1106.233
Thermodynamics and Instabilities of a Strongly Coupled Anisotropic Plasma
We extend our analysis of a IIB supergravity solution dual to a spatially
anisotropic finite-temperature N=4 super Yang-Mills plasma. The solution is
static, possesses an anisotropic horizon, and is completely regular. The full
geometry can be viewed as a renormalization group flow from an AdS geometry in
the ultraviolet to a Lifshitz-like geometry in the infrared. The anisotropy can
be equivalently understood as resulting from a position-dependent theta-term or
from a non-zero number density of dissolved D7-branes. The holographic stress
tensor is conserved and anisotropic. The presence of a conformal anomaly plays
an important role in the thermodynamics. The phase diagram exhibits homogeneous
and inhomogeneous (i.e. mixed) phases. In some regions the homogeneous phase
displays instabilities reminiscent of those of weakly coupled plasmas. We
comment on similarities with QCD at finite baryon density and with the
phenomenon of cavitation.Comment: 62 pages, 13 figures; v2: typos fixed, added reference
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