994 resultados para Effective focal length


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The objective of this work was to evaluate 210 Bacillus thuringiensis strains against Aedes aegypti and Culex quinquefasciatus larvae to select the most effective. These strains were isolated from different regions of Brazil and are stored in a Bacillus spp. collection at Embrapa Recursos Genéticos e Biotecnologia, Brasília, Brazil. The selected strains were characterized by morphological (microscopy), biochemical (SDS-PAGE 10%) and molecular (PCR) methods. Six B. thuringiensis strains were identified as mosquito-toxic after the selective bioassays. None of the strains produced the expected PCR products for detection of cry4, cry11 and cyt1A genes. These results indicate that the activity of mosquitocidal Brazilian strains are not related with Cry4, Cry11 or Cyt proteins, so they could be used as an alternative bioinsecticide against mosquitoes.

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Evolution of the neurochemical profile consisting of 19 metabolites after 30 mins of middle cerebral artery occlusion was longitudinally assessed at 3, 8 and 24 h in 6 to 8 microL volumes in the striatum using localized 1H-magnetic resonance spectroscopy at 14.1 T. Profound changes were detected as early as 3 h after ischemia, which include elevated lactate levels in the presence of significant glucose concentrations, decreases in glutamate and a transient twofold glutamine increase, likely to be linked to the excitotoxic release of glutamate and conversion into glial glutamine. Interestingly, decreases in N-acetyl-aspartate (NAA), as well as in taurine, exceeded those in neuronal glutamate, suggesting that the putative neuronal marker NAA is rather a sensitive marker of neuronal viability. With further ischemia evolution, additional, more profound concentration decreases were detected, reflecting a disruption of cellular functions. We conclude that early changes in markers of energy metabolism, glutamate excitotoxicity and neuronal viability can be detected with high precision non-invasively in mice after stroke. Such investigations should lead to a better understanding and insight into the sequential early changes in the brain parenchyma after ischemia, which could be used for identifying new targets for neuroprotection.

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The relation between the low-energy constants appearing in the effective field theory description of the Lambda N -> NN transition potential and the parameters of the one-meson-exchange model previously developed is obtained. We extract the relative importance of the different exchange mechanisms included in the meson picture by means of a comparison to the corresponding operational structures appearing in the effective approach. The ability of this procedure to obtain the weak baryon-baryon-meson couplings for a possible scalar exchange is also discussed.

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The relation between the low-energy constants appearing in the effective field theory description of the Lambda N -> NN transition potential and the parameters of the one-meson-exchange model previously developed is obtained. We extract the relative importance of the different exchange mechanisms included in the meson picture by means of a comparison to the corresponding operational structures appearing in the effective approach. The ability of this procedure to obtain the weak baryon-baryon-meson couplings for a possible scalar exchange is also discussed.

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BACKGROUND: Dermatophytes are the main cause of onychomycoses, but various nondermatophyte filamentous fungi are often isolated from abnormal nails. The correct identification of the aetiological agent of nail infections is necessary in order to recommend appropriate treatment. OBJECTIVE: To evaluate a rapid polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay based on 28S rDNA for fungal identification in nails on a large number of samples in comparison with cultures. METHODS: Infectious fungi were analysed using PCR-RFLP in 410 nail samples in which fungal elements were observed in situ by direct mycological examination (positive samples). The results were compared with those previously obtained by culture of fungi on Sabouraud agar from the same nail samples. RESULTS: PCR-RFLP identification of fungi in nails allowed validation of the results obtained in culture when Trichophyton spp. grew from infected samples. In addition, nondermatophyte filamentous fungi could be identified with certainty as the infectious agents in onychomycosis, and discriminated from dermatophytes as well as from transient contaminants. The specificity of the culture results relative to PCR-RFLP appeared to be 81%, 71%, 52% and 63% when Fusarium spp., Scopulariopsis brevicaulis, Aspergillus spp. and Candida spp., respectively, grew on Sabouraud agar. It was also possible to identify the infectious agent when direct nail mycological examination showed fungal elements, but negative results were obtained from fungal culture. CONCLUSIONS: Improved sensitivity for the detection of fungi in nails was obtained using the PCR-RFLP assay. Rapid and reliable molecular identification of the infectious fungus can be used routinely and presents several important advantages compared with culture in expediting the choice of appropriate antifungal therapy.

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Portland cement concrete is an outstanding structural material but stresses and cracks often occur in large structures due to drying shrinkage. The objective of this research was to determine the change in length due to loss of moisture from placement through complete drying of portland cement concrete. The drying shrinkage was determined for four different combinations of Iowa DOT structural concrete mix proportions and materials. The two mix proportions used were an Iowa DOT D57 (bridge deck mix proportions) and a water reduced modified C4 mix. Three 4"x 4"x 18" beams were made for each mix. After moist curing for three days, all beams were maintained in laboratory dry air and the length and weight were measured at 73°F ± 3°F. The temperature was cycled on alternate days from 73°F to 90°F through four months. From four months through six months, the temperature was cycled one day at 73°F and six days at 130°F. It took approximately six months for the concrete to reach a dry condition with these temperatures. The total drying shrinkage for the four mixes varied from .0106 in. to .0133 in. with an average of .0120 in. The rate of shrinkage was approximately .014% shrinkage per 1% moisture loss for all four mixes. The rate and total shrinkage for all four mixes was very similar and did not seem to depend on the type of coarse aggregate or the use of a retarder.

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Two portable Radio Frequency IDentification (RFID) systems (made by Texas Instruments and HiTAG) were developed and tested for bridge scour monitoring by the Department of Civil and Environmental Engineering at the University of Iowa (UI). Both systems consist of three similar components: 1) a passive cylindrical transponder of 2.2 cm in length (derived from transmitter/responder); 2) a low frequency reader (~134.2 kHz frequency); and 3) an antenna (of rectangular or hexagonal loop). The Texas Instruments system can only read one smart particle per time, while the HiTAG system was successfully modified here at UI by adding the anti-collision feature. The HiTAG system was equipped with four antennas and could simultaneously detect 1,000s of smart particles located in a close proximity. A computer code was written in C++ at the UI for the HiTAG system to allow simultaneous, multiple readouts of smart particles under different flow conditions. The code is written for the Windows XP operational system which has a user-friendly windows interface that provides detailed information regarding the smart particle that includes: identification number, location (orientation in x,y,z), and the instance the particle was detected.. These systems were examined within the context of this innovative research in order to identify the best suited RFID system for performing autonomous bridge scour monitoring. A comprehensive laboratory study that included 142 experimental runs and limited field testing was performed to test the code and determine the performance of each system in terms of transponder orientation, transponder housing material, maximum antenna-transponder detection distance, minimum inter-particle distance and antenna sweep angle. The two RFID systems capabilities to predict scour depth were also examined using pier models. The findings can be summarized as follows: 1) The first system (Texas Instruments) read one smart particle per time, and its effective read range was about 3ft (~1m). The second system (HiTAG) had similar detection ranges but permitted the addition of an anti-collision system to facilitate the simultaneous identification of multiple smart particles (transponders placed into marbles). Therefore, it was sought that the HiTAG system, with the anti-collision feature (or a system with similar features), would be preferable when compared to a single-read-out system for bridge scour monitoring, as the former could provide repetitive readings at multiple locations, which could help in predicting the scour-hole bathymetry along with maximum scour depth. 2) The HiTAG system provided reliable measures of the scour depth (z-direction) and the locations of the smart particles on the x-y plane within a distance of about 3ft (~1m) from the 4 antennas. A Multiplexer HTM4-I allowed the simultaneous use of four antennas for the HiTAG system. The four Hexagonal Loop antennas permitted the complete identification of the smart particles in an x, y, z orthogonal system as function of time. The HiTAG system can be also used to measure the rate of sediment movement (in kg/s or tones/hr). 3) The maximum detection distance of the antenna did not change significantly for the buried particles compared to the particles tested in the air. Thus, the low frequency RFID systems (~134.2 kHz) are appropriate for monitoring bridge scour because their waves can penetrate water and sand bodies without significant loss of their signal strength. 4) The pier model experiments in a flume with first RFID system showed that the system was able to successfully predict the maximum scour depth when the system was used with a single particle in the vicinity of pier model where scour-hole was expected. The pier model experiments with the second RFID system, performed in a sandbox, showed that system was able to successfully predict the maximum scour depth when two scour balls were used in the vicinity of the pier model where scour-hole was developed. 5) The preliminary field experiments with the second RFID system, at the Raccoon River, IA near the Railroad Bridge (located upstream of 360th street Bridge, near Booneville), showed that the RFID technology is transferable to the field. A practical method would be developed for facilitating the placement of the smart particles within the river bed. This method needs to be straightforward for the Department of Transportation (DOT) and county road working crews so it can be easily implemented at different locations. 6) Since the inception of this project, further research showed that there is significant progress in RFID technology. This includes the availability of waterproof RFID systems with passive or active transponders of detection ranges up to 60 ft (~20 m) within the water–sediment column. These systems do have anti-collision and can facilitate up to 8 powerful antennas which can significantly increase the detection range. Such systems need to be further considered and modified for performing automatic bridge scour monitoring. The knowledge gained from the two systems, including the software, needs to be adapted to the new systems.

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Focal therapy is a novel treatment strategy in prostate cancer aiming to treat only the area of the gland harbouring clinically significant disease. The overall objective is to maintain the oncological benefit of active treatment while minimising treatment-related morbidity. Leading centres are currently evaluating various minimally invasive technologies in a rigorous manner. Oncological and functional results in mid-term are encouraging with low rate of urinary incontinence and erectile dysfunction. However, the oncological outcome needs to be evaluated in the long-term in the light of the prolonged natural history of the disease.

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In mammals, transcriptional autorepression by Period (PER) and Cryptochrome (CRY) protein complexes is essential for the generation of circadian rhythms. We have identified CAVIN-3 as a new, cytoplasmic PER2-interacting protein influencing circadian clock properties. Thus, CAVIN-3 loss- and gain-of-function shortened and lengthened, respectively, the circadian period in fibroblasts and affected PER:CRY protein abundance and interaction. While depletion of protein kinase Cδ (PKCδ), a known partner of CAVIN-3, had little effect on circadian gene expression, CAVIN-3 required the PKCδ-binding site to exert its effect on period length. This suggests the involvement of yet uncharacterized protein kinases. Finally, CAVIN-3 activity in circadian gene expression was independent of caveolae.

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Viruses have developed strategies to counteract signalling through Toll-like receptors (TLRs) that are involved in the detection of viruses and induction of proinflammatory cytokines and IFNs. Vaccinia virus (VACV) encodes A46 protein which disrupts TLR signalling by interfering with TLR: adaptor interactions. Since the innate immune response to viruses is critical to induce protective immunity, we studied whether deletion of A46R gene in a NYVAC vector expressing HIV-1 Env, Gag, Pol and Nef antigens (NYVAC-C) improves immune responses against HIV-1 antigens. This question was examined in human macrophages and in mice infected with a single A46R deletion mutant of the vaccine candidate NYVAC-C (NYVAC-C-ΔA46R). The viral gene A46R is not required for virus replication in primary chicken embryo fibroblast (CEF) cells and its deletion in NYVAC-C markedly increases TNF, IL-6 and IL-8 secretion by human macrophages. Analysis of the immune responses elicited in BALB/c mice after DNA prime/NYVAC boost immunization shows that deletion of A46R improves the magnitude of the HIV-1-specific CD4 and CD8 T cell immune responses during adaptive and memory phases, maintains the functional profile observed with the parental NYVAC-C and enhances anti-gp120 humoral response during the memory phase. These findings establish the immunological role of VACV A46R on innate immune responses of macrophages in vitro and antigen-specific T and B cell immune responses in vivo and suggest that deletion of viral inhibitors of TLR signalling is a useful approach for the improvement of poxvirus-based vaccine candidates.