928 resultados para NSO enhancement
Resumo:
Dentro del campo de la ciudad como lugar se analiza el concepto de planificación territorial y planeamiento espacial. Flooding is one of the main risks associated to many urban settlements in Spain and, indeed, elsewhere. The location of cities has traditionally ignored this type of risk as other locational criteria prevailed (communications, crop yields, etc.). Defence engineering has been the customary way to offset the risk but, nowadays, the opportunity costs of engineering works in urban areas has highlighted the interest of “soft measures” based on prevention. Early warning systems plus development planning controls rank among the most favoured ones. This paper reflects the results of a recent EU-financed research project on alternative measures geared to the enhancement of urban resilience against flooding. A city study in Spain is used as example of those measures.
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Laser shock processing (LSP) is increasingly applied as an effective technology for the improvement of metallic materials mechanical properties in different types of components as a means of enhancement of their fatigue life behavior. As reported in previous contributions by the authors, a main effect resulting from the application of the LSP technique consists on the generation of relatively deep compression residual stresses fields into metallic components allowing an improved mechanical behaviour, explicitly the life improvement of the treated specimens against wear, crack growth and stress corrosion cracking. Additional results accomplished by the authors in the line of practical development of the LSP technique at an experimental level (aiming its integral assessment from an interrelated theoretical and experimental point of view)are presented in this paper. Concretely, experimental results on the residual stress profiles and associated mechanical properties modification successfully reached in typical materials under different LSP irradiation conditions are presented. In this case, the specific behavior of a widely used material in high reliability components (especially in nuclear and biomedical applications) as AISI 316L is analyzed, the effect of possible “in-service” thermal conditions on the relaxation of the LSP effects being specifically characterized.
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Nowadays, a lot of applications use digital images. For example in face recognition to detect and tag persons in photograph, for security control, and a lot of applications that can be found in smart cities, as speed control in roads or highways and cameras in traffic lights to detect drivers ignoring red light. Also in medicine digital images are used, such as x-ray, scanners, etc. These applications depend on the quality of the image obtained. A good camera is expensive, and the image obtained depends also on external factor as light. To make these applications work properly, image enhancement is as important as, for example, a good face detection algorithm. Image enhancement also can be used in normal photograph, for pictures done in bad light conditions, or just to improve the contrast of an image. There are some applications for smartphones that allow users apply filters or change the bright, colour or contrast on the pictures. This project compares four different techniques to use in image enhancement. After applying one of these techniques to an image, it will use better the whole available dynamic range. Some of the algorithms are designed for grey scale images and others for colour images. It is used Matlab software to develop and present the final results. These algorithms are Successive Means Quantization Transform (SMQT), Histogram Equalization, using Matlab function and own implemented function, and V transform. Finally, as conclusions, we can prove that Histogram equalization algorithm is the simplest of all, it has a wide variability of grey levels and it is not suitable for colour images. V transform algorithm is a good option for colour images. The algorithm is linear and requires low computational power. SMQT algorithm is non-linear, insensitive to gain and bias and it can extract structure of the data. RESUMEN. Hoy en día incontable número de aplicaciones usan imágenes digitales. Por ejemplo, para el control de la seguridad se usa el reconocimiento de rostros para detectar y etiquetar personas en fotografías o vídeos, para distintos usos de las ciudades inteligentes, como control de velocidad en carreteras o autopistas, cámaras en los semáforos para detectar a conductores haciendo caso omiso de un semáforo en rojo, etc. También en la medicina se utilizan imágenes digitales, como por ejemplo, rayos X, escáneres, etc. Todas estas aplicaciones dependen de la calidad de la imagen obtenida. Una buena cámara es cara, y la imagen obtenida depende también de factores externos como la luz. Para hacer que estas aplicaciones funciones correctamente, el tratamiento de imagen es tan importante como, por ejemplo, un buen algoritmo de detección de rostros. La mejora de la imagen también se puede utilizar en la fotografía no profesional o de consumo, para las fotos realizadas en malas condiciones de luz, o simplemente para mejorar el contraste de una imagen. Existen aplicaciones para teléfonos móviles que permiten a los usuarios aplicar filtros y cambiar el brillo, el color o el contraste en las imágenes. Este proyecto compara cuatro técnicas diferentes para utilizar el tratamiento de imagen. Se utiliza la herramienta de software matemático Matlab para desarrollar y presentar los resultados finales. Estos algoritmos son Successive Means Quantization Transform (SMQT), Ecualización del histograma, usando la propia función de Matlab y una nueva función que se desarrolla en este proyecto y, por último, una función de transformada V. Finalmente, como conclusión, podemos comprobar que el algoritmo de Ecualización del histograma es el más simple de todos, tiene una amplia variabilidad de niveles de gris y no es adecuado para imágenes en color. El algoritmo de transformada V es una buena opción para imágenes en color, es lineal y requiere baja potencia de cálculo. El algoritmo SMQT no es lineal, insensible a la ganancia y polarización y, gracias a él, se puede extraer la estructura de los datos.
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We have found that ectopic expression of cyclin A increases hormone-dependent and hormone-independent transcriptional activation by the estrogen receptor in vivo in a number of cell lines, including HeLa cells, U-2 OS osteosarcoma cells and Hs 578Bst breast epithelial cells. This effect can be further enhanced in HeLa cells by the concurrent expression of the cyclin-dependent kinase activator, cyclin H, and cdk7, and abolished by expression of the cdk inhibitor, p27KIP1, or by the expression of a dominant negative catalytically inactive cdk2 mutant. ER is phosphorylated between amino acids 82 and 121 in vitro by the cyclin A/cdk2 complex and incorporation of phosphate into ER is stimulated by ectopic expression of cyclin A in vivo. Together, these results strongly suggest a direct role for the cyclin A/cdk2 complex in phosphorylating ER and regulating its transcriptional activity.
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The stimulation by Flk2-ligand (FL) of blast colony formation by murine bone marrow cells was selectively potentiated by the addition of regulators sharing in common the gp130 signaling receptor–leukemia inhibitory factor (LIF), oncostatin M, interleukin 11, or interleukin 6. Recloning of blast colony cells indicated that the majority were progenitor cells committed exclusively to macrophage formation and responding selectively to proliferative stimulation by macrophage colony-stimulating factor. Reculture of blast colony cells initiated by FL plus LIF in cultures containing granulocyte/macrophage colony-stimulating factor plus tumor necrosis factor α indicated that at least some of the cells were capable of maturation to dendritic cells. The cells forming blast colonies in response to FL plus LIF were unrelated to those forming blast colonies in response to stimulation by stem cell factor and appear to be a distinct subset of mature hematopoietic stem cells.
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While chemical synapses are very plastic and modifiable by defined activity patterns, gap junctions, which mediate electrical transmission, have been classically perceived as passive intercellular channels. Excitatory transmission between auditory afferents and the goldfish Mauthner cell is mediated by coexisting gap junctions and glutamatergic synapses. Although an increased intracellular Ca2+ concentration is expected to reduce gap junctional conductance, both components of the synaptic response were instead enhanced by postsynaptic increases in Ca2+ concentration, produced by patterned synaptic activity or intradendritic Ca2+ injections. The synaptically induced potentiations were blocked by intradendritic injection of KN-93, a Ca2+/calmodulin-dependent kinase (CaM-K) inhibitor, or CaM-KIINtide, a potent and specific peptide inhibitor of CaM-KII, whereas the responses were potentiated by injection of an activated form of CaM-KII. The striking similarities of the mechanisms reported here with those proposed for long-term potentiation of mammalian glutamatergic synapses suggest that gap junctions are also similarly regulated and indicate a primary role for CaM-KII in shaping and regulating interneuronal communication, regardless of its modality.
Resumo:
Secretion of neurotransmitters is initiated by voltage-gated calcium influx through presynaptic, voltage-gated N-type calcium channels. These channels interact with the SNARE proteins, which are core components of the exocytosis process, via the synaptic protein interaction (synprint) site in the intracellular loop connecting domains II and III of their α1B subunit. Interruption of this interaction by competing synprint peptides inhibits fast, synchronous transmitter release. Here we identify a voltage-dependent, but calcium-independent, enhancement of transmitter release that is elicited by trains of action potentials in the presence of a hyperosmotic extracellular concentration of sucrose. This enhancement of transmitter release requires interaction of SNARE proteins with the synprint site. Our results provide evidence for a voltage-dependent signal that is transmitted by protein–protein interactions from the N-type calcium channel to the SNARE proteins and enhances neurotransmitter release by altering SNARE protein function.
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Enhancers are defined by their ability to stimulate gene activity from remote sites and their requirement for promoter-proximal upstream activators to activate transcription. Here we demonstrate that recruitment of the p300/CBP-associated factor PCAF to a reporter gene is sufficient to stimulate promoter activity. The PCAF-mediated stimulation of transcription from either a distant or promoter-proximal position depends on the presence of an upstream activator (Sp1). These data suggest that acetyltransferase activity may be a primary component of enhancer function, and that recruitment of polymerase and enhancement of transcription are separable. Transcriptional activation by PCAF requires both its acetyltransferase activity and an additional activity within its N terminus. We also show that the simian virus 40 enhancer and PCAF itself are sufficient to counteract Mad-mediated repression. These results are compatible with recent models in which gene activity is regulated by the competition between deacetylase-mediated repression and enhancer-mediated recruitment of acetyltransferases.
Resumo:
Superoxide anion (O2−) plays a key role in the endogenous suppression of endothelium-derived nitric oxide (NO) bioactivity and has been implicated in the development of hypertension. In previous studies, we found that O2− is produced predominantly in the adventitia of isolated rabbit aorta and acts as a barrier to NO. In the present studies, we characterize the enzyme responsible for O2− production in the adventitia and show that this enzyme is a constitutively active NADPH oxidase with similar composition as the phagocyte NADPH oxidase. Constitutive O2−-generating activity was localized to aortic adventitial fibroblasts and was enhanced by the potent vasoconstrictor angiotensin II. Immunohistochemistry of aortic sections demonstrated the presence of p22phox, gp91phox, p47phox, and p67phox localized exclusively in rabbit aortic adventitia, coincident with the site of staining for O2− production. Furthermore, immunodepletion of p67phox from adventitial fibroblast particulates resulted in the loss of NADPH oxidase activity, which could be restored by the addition of recombinant p67phox. Further study into the regulation of this adventitial source of O2− is important in elucidating the mechanisms regulating the bioactivity of NO and may contribute to our understanding of the pathogenesis of hypertension.
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The increased expression of epidermal growth factor receptor induced by tumor necrosis factor α renders pancreatic cancer cells more susceptible to antibody-dependent cellular cytotoxicity by a mAb specific for this receptor. Laboratory studies with athymic mice bearing xenografts of human pancreatic cancer cells demonstrated a cytokine-induced ability of the mAb to cause significant tumor regression. In a phase I/II clinical trial, 26 patients with unresectable pancreatic cancer were enrolled into three cohorts receiving variable amounts of the antibody together with a constant amount of tumor necrosis factor α. With increasing doses of antibody, the growth of the primary tumor was significantly inhibited. This was reflected by a longer median survival, with one complete remission lasting for 3 years obtained with the highest dose of antibody employed. Thus, a combination of the cytokine, tumor necrosis factor α, with a mAb to the epidermal growth factor receptor offers a potentially useful approach for the treatment of pancreatic cancer.
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Thymidine dinucleotide (pTpT) stimulates melanogenesis in mammalian pigment cells and intact skin, mimicking the effects of UV irradiation and UV-mimetic DNA damage. Here it is shown that, in addition to tanning, pTpT induces a second photoprotective response, enhanced repair of UV-induced DNA damage. This enhanced repair results in a 2-fold increase in expression of a UV-damaged chloramphenicol acetyltransferase expression vector transfected into pTpT-treated skin fibroblasts and keratinocytes, compared with diluent-treated cells. Direct measurement of thymine dimers and (6–4) photoproducts by immunoassay demonstrates faster repair of both of these UV-induced photoproducts in pTpT-treated fibroblasts. This enhanced repair capacity also improves cell survival and colony-forming ability after irradiation. These effects of pTpT are accomplished, at least in part, by the up-regulation of a set of genes involved in DNA repair (ERCC3 and GADD45) and cell cycle inhibition (SDI1). At least two of these genes (GADD45 and SDI1) are known to be transcriptionally regulated by the p53 tumor suppressor protein. Here we show that pTpT activates p53, leading to nuclear accumulation of this protein, and also increases the specific binding of this transcription factor to its DNA consensus sequence.
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Most cases of autosomal-dominant familial Alzheimer's disease are linked to mutations in the presenilin genes (PS1 and PS2). In addition to modulating β-amyloid production, presenilin mutations also produce highly specific and selective alterations in intracellular calcium signaling. Although the molecular mechanisms underlying these changes are not known, one candidate molecular mediator is calsenilin, a recently identified calcium-binding protein that associates with the C terminus of both PS1 and PS2. In this study, we investigated the effects of calsenilin on calcium signaling in Xenopus oocytes expressing either wild-type or mutant PS1. In this system, mutant PS1 potentiated the amplitude of calcium signals evoked by inositol 1,4,5-trisphosphate and also accelerated their rates of decay. We report that calsenilin coexpression reverses both of these potentially pathogenic effects. Notably, expression of calsenilin alone had no discernable effects on calcium signaling, suggesting that calsenilin modulates these signals by a mechanism independent of simple calcium buffering. Our findings further suggest that the effects of presenilin mutations on calcium signaling are likely mediated through the C-terminal domain, a region that has also been implicated in the modulation of β-amyloid production and cell death.
Resumo:
The plant-signaling molecules salicylic acid (SA) and jasmonic acid (JA) play an important role in induced disease resistance pathways. Cross-talk between SA- and JA-dependent pathways can result in inhibition of JA-mediated defense responses. We investigated possible antagonistic interactions between the SA-dependent systemic acquired resistance (SAR) pathway, which is induced upon pathogen infection, and the JA-dependent induced systemic resistance (ISR) pathway, which is triggered by nonpathogenic Pseudomonas rhizobacteria. In Arabidopsis thaliana, SAR and ISR are effective against a broad spectrum of pathogens, including the foliar pathogen Pseudomonas syringae pv. tomato (Pst). Simultaneous activation of SAR and ISR resulted in an additive effect on the level of induced protection against Pst. In Arabidopsis genotypes that are blocked in either SAR or ISR, this additive effect was not evident. Moreover, induction of ISR did not affect the expression of the SAR marker gene PR-1 in plants expressing SAR. Together, these observations demonstrate that the SAR and the ISR pathway are compatible and that there is no significant cross-talk between these pathways. SAR and ISR both require the key regulatory protein NPR1. Plants expressing both types of induced resistance did not show elevated Npr1 transcript levels, indicating that the constitutive level of NPR1 is sufficient to facilitate simultaneous expression of SAR and ISR. These results suggest that the enhanced level of protection is established through parallel activation of complementary, NPR1-dependent defense responses that are both active against Pst. Therefore, combining SAR and ISR provides an attractive tool for the improvement of disease control.
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Evidence indicates that the modulatory effects of the adrenergic stress hormone epinephrine as well as several other neuromodulatory systems on memory storage are mediated by activation of β-adrenergic mechanisms in the amygdala. In view of our recent findings indicating that the amygdala is involved in mediating the effects of glucocorticoids on memory storage, the present study examined whether the glucocorticoid-induced effects on memory storage depend on β-adrenergic activation within the amygdala. Microinfusions (0.5 μg in 0.2 μl) of either propranolol (a nonspecific β-adrenergic antagonist), atenolol (a β1-adrenergic antagonist), or zinterol (a β2-adrenergic antagonist) administered bilaterally into the basolateral nucleus of the amygdala (BLA) of male Sprague–Dawley rats 10 min before training blocked the enhancing effect of posttraining systemic injections of dexamethasone (0.3 mg/kg) on 48-h memory for inhibitory avoidance training. Infusions of these β-adrenergic antagonists into the central nucleus of the amygdala did not block the dexamethasone-induced memory enhancement. Furthermore, atenolol (0.5 μg) blocked the memory-enhancing effects of the specific glucocorticoid receptor (GR or type II) agonist RU 28362 infused concurrently into the BLA immediately posttraining. These results strongly suggest that β-adrenergic activation is an essential step in mediating glucocorticoid effects on memory storage and that the BLA is a locus of interaction for these two systems.
Resumo:
Recent measurements of sedimentation equilibrium and sedimentation velocity have shown that the bacterial cell division protein FtsZ self-associates to form indefinitely long rod-like linear aggregates in the presence of GDP and Mg2+. In the present study, the newly developed technique of non-ideal tracer sedimentation equilibrium was used to measure the effect of high concentrations—up to 150 g/liter—of each of two inert “crowder” proteins, cyanmethemoglobin or BSA, on the thermodynamic activity and state of association of dilute FtsZ under conditions inhibiting (−Mg2+) and promoting (+Mg2+) FtsZ self-association. Analysis of equilibrium gradients of both FtsZ and crowder proteins indicates that, under the conditions of the present experiment, FtsZ interacts with each of the two crowder proteins essentially entirely via steric repulsion, which may be accounted for quantitatively by a simple model in which hemoglobin, albumin, and monomeric FtsZ are modeled as effective spherical hard particles, and each oligomeric species of FtsZ is modeled as an effective hard spherocylinder. The functional dependence of the sedimentation of FtsZ on the concentrations of FtsZ and either crowder indicates that, in the presence of high concentrations of crowder, both the weight-average degree of FtsZ self-association and the range of FtsZ oligomer sizes present in significant abundance are increased substantially.