852 resultados para RCE-PD (resonant-cavity-enhanced photodiode)
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We report on advanced dual-wavelength digital holographic microscopy (DHM) methods, enabling single-acquisition real-time micron-range measurements while maintaining single-wavelength interferometric resolution in the nanometer regime. In top of the unique real-time capability of our technique, it is shown that axial resolution can be further increased compared to single-wavelength operation thanks to the uncorrelated nature of both recorded wavefronts. It is experimentally demonstrated that DHM topographic investigation within 3 decades measurement range can be achieved with our arrangement, opening new applications possibilities for this interferometric technique. ©2008 COPYRIGHT SPIE
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Deltamethrin and other pyrethroids have been extensively used in Argentina since 1980, for the chemical control of Triatoma infestans Klug (Hemiptera: Reduviidae). Recently, resistance to deltamethrin was detected in field populations by the survival of bugs exposed by topical application to the diagnostic dose estimated on the CIPEIN susceptible strain. Results of the current study showed low resistant ratios (RRs) to deltamethrin for the resistant populations (RR ranged from 2.0 for San Luis colony to 7.9 for Salta colony). Biochemical studies were made on the most resistant colony (Salta) and the susceptible strain (CIPEIN), in order to establish the importance of degradative mechanisms as a cause of the detected resistance. Esterase activity was measured on 3 days old first instars through phenylthioacetate and a-naphtyl acetate activities. The results showed a significant difference in no cholinesterase esterase activity from susceptible (7.6 ± 0,7 µM S./i.min.) and Salta resistant colony (9.5 ± 0.8 µM S./i.min.). Cytochrome P450 mono-oxygenase (P450) activity was measured on individual insects through ethoxycoumarine deethylase (ECOD) activity using a fluorescence micro plate reader. The dependence of ECOD activity on age and body region of the nymphs, and pH and time of incubation were studied in order to optimize the measurement. As a result, comparative studies were performed on abdomens of 2 days old first instars at pH 7.2 and 4 h incubation time. ECOD activity of first nymphs was significantly lower in the susceptible colony (61.3 ± 9.08 pg ECOD/ insect) than in the resistant one (108.1± 5.7 pg ECOD/ insect). These results suggest that degradative esterases (no-cholinesterase) and mono-oxygenases cytochrome P450, play an important role in the resistance to deltamethrin in Salta colony from Argentina.
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Physical activity is beneficial for healthy ageing. It may also help maintain good cognitive function in older age. Aerobic activity improves cardiovascular fitness, but it is not known whether this sort of fitness is necessary for improved cognitive function.��Eleven studies of aerobic physical activity programmes for healthy people over the age of 55 years have been included in this review. Eight of these 11 studies reported that aerobic exercise interventions resulted in increased fitness of the trained group and an improvement in at least one aspect of cognitive function. The largest effects were on cognitive speed, auditory and visual attention. However, the cognitive functions which improved were not the same in each study and the majority of comparisons yielded no significant results.��The data are insufficient to show that the improvements in cognitive function which can be attributed to physical exercise are due to improvements in cardiovascular fitness.
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Purpose: To report the magnetic resonance imaging (MRI) findings in athletic injuries of the extensor carpi ulnaris (ECU) subsheath, assessing the utility of gadolinium-enhanced (Gd) fat-saturated (FS) T1-weighted sequences with wrist pronation and supination. Methods and Materials: Sixteen patients (13 males, 3 females; mean age 30.3 years) with athletic injuries of the ECU subsheath sustained between January 2003 and June 2009 were included in this retrospective study. Initial and follow‑up 1.5-T wrist MRIs were performed with transverse T1-weighted and STIR sequences in pronation, and Gd FS T1-weighted sequences with wrist pronation and supination. Two radiologists assessed the type of injury (A to C), ECU tendon stability, associated lesions and rated pulse sequences using a three-point scale: 1 = poor, 2 = good and 3 = excellent. Results: Gd-enhanced FS T1-weighted transverse sequences in supination (2.63) and pronation (2.56) were most valuable, compared with STIR (2.19) and T1 weighted (1.94). Nine type A, one type B and six type C injuries were found. There were trends towards diminution in size, signal intensity and enhancement of associated pouches on follow‑up MRI and tendon stabilisation within the ulnar groove. Conclusion: Gd-enhanced FS T1-weighted sequences with wrist pronation and supination are most valuable in assessing and follow‑up athletic injuries of the ECU subsheath on 1.5-T MRI.
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Tamoxifen (tam) is a widely used endocrine therapy in the treatment of early and advanced stage breast cancer in women and men. It is a pro-drug having weak affinity with the estrogen receptor and needs to be converted to its main metabolite, endoxifen (endox), to have full anticancer activity. Cytochrome 2D6 (CYP2D6) plays a major role in the metabolism of tamoxifen to endoxifen. It is genetically highly polymorphic and its activity influences profoundly the synthesis of endoxifen and potentially the efficacy of tamoxifen treatment. Genotyping is currently the most widely used approach in studies and also in clinical practice to categorize patients as poor- (PM), intermediate- (IM), extensive- (EM) and ultra rapid-metabolizers (UM). Some clinicians already use genotyping in order to tailor the endocrine therapy of their patients. Owing to the large inter-individual variations in concentrations of the active moitey due to genetic and non-genetic influences renders the predictive value of the test uncertain for an individual patient. A significant number of patients classified as EM or IM by genotyping have indeed relatively low endoxifen levels similar to PMs1. This suggests that genotyping is probably not the opti ma l meth o d f or predi cti ng end oxif en l evels.
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This article presents preliminary findings from a research study conducted by the Institute for the Study of Knowledge Management in Education on the role of open educational resources (OER) in transforming pedagogy. Based on a study of art and humanities teachers participating in an OER training network, the study reveals how exposure to OER resources and tools support collaboration among teachers, as well as new conversations about teaching practices. These findings have implications for engaging teachers in adopting new OER use practices, and for how OER can be integrated as a model for innovation in teaching and in resource development.
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We report two cases of extranodal NK/T-cell lymphoma, nasal type, in immunocompetent patients without nasal cavity involvement. In the two cases, the initial presumptive diagnosis was tuberculosis and there was a rapid dissemination of the tumor with short survival after the hospital admittance. An autopsy was performed showing infiltration in several organs including lymph nodes and mesenteric and retroperitoneal fat. Histological sections showed an angiocentric and angiodestructive growth pattern and the immunophenotype was CD45+, CD3+ (cytoplasmic), as well as Granzyme B+ and EBV+. However, CD56 expression was only positive in a case in which the molecular study showed T-cell gene rearrangement with monoclonal appearance and associated with hemophagocytic syndrome. These cases represent rare examples of NK/T-cell lymphoma disseminated outside the nasal cavity highly aggressive that lead to the rapid death of the patients.
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Objective. Mandibular osteoradionecrosis (ORN) is a serious complication of radiotherapy (RT) in head and neck cancer patients. The aim of this study was to analyze the incidence of and risk factors for mandibular ORN in squamous cell carcinoma (SCC) of the oral cavity and oropharynx.Study Design. Case series with chart review.Setting. University tertiary care center for head and neck oncology.Subjects and Methods. Seventy-three patients treated for stage I to IV SCC of the oral cavity and oropharynx between 2000 and 2007, with a minimum follow-up of 2 years, were included in the study. Treatment modalities included both RT with curative intent and adjuvant RT following tumor surgery. The log-rank test and Cox model were used for univariate and multivariate analyses.Results. The incidence of mandibular ORN was 40% at 5 years. Using univariate analysis, the following risk factors were identified: oral cavity tumors (P < .01), bone invasion (P < .02), any surgery prior to RT (P < .04), and bone surgery (P < .0001). By multivariate analysis, mandibular surgery proved to be the most important risk factor and the only one reaching statistical significance (P < .0002).Conclusion. Mandibular ORN is a frequent long-term complication of RT for oral cavity and oropharynx cancers. Mandibular surgery before irradiation is the only independent risk factor. These aspects must be considered when planning treatment for these tumors.
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In this study, the vaporization behaviour of solid Pd-rich phases in the Pd-Pb, Pd-In and Pd-Sn systems was investigated by Knudsen-effusion-cell coupled with mass-spectrometry. The Pb, Pd, In vapor pressures [no Sn(g) has been detected in the vapor of Pd-Sn system] were evaluated in the temperatures range 1190-1563 K from the ion intensities measured over two-phases regions. Thermodynamic quantities were derived from vapor pressure data. In particular, for the Pd-Sn binary, the intermediate phase Pd7Sn2, the existence of which has been recently proposed, has been studied here for the first time. Furthermore, preliminary thermochemical data are presented for the diatomic intermetallic molecules PdSn and PdPb, which have been for the first time identified in the vapors in equilibrium over liquid solutions of appropriate composition at higher temperatures (1935-2025 K). (C) 2000 Elsevier Science Ltd. All rights reserved.
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This paper focuses on QoS routing with protection in an MPLS network over an optical layer. In this multi-layer scenario each layer deploys its own fault management methods. A partially protected optical layer is proposed and the rest of the network is protected at the MPLS layer. New protection schemes that avoid protection duplications are proposed. Moreover, this paper also introduces a new traffic classification based on the level of reliability. The failure impact is evaluated in terms of recovery time depending on the traffic class. The proposed schemes also include a novel variation of minimum interference routing and shared segment backup computation. A complete set of experiments proves that the proposed schemes are more efficient as compared to the previous ones, in terms of resources used to protect the network, failure impact and the request rejection ratio
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Molar heat capacities at constant pressure of six solid solutions and 11 intermediate phases in the Pd-Pb, Pd-Sn and Pd-In systems were determined each 10 K by differential scanning calorimetry from 310 to 1000 K, The experimental values have been fitted by polynomials C-p = a + bT + cT(2) + d/T-2. Results are given, discussed and compared with available literature data. (C) 2001 Elsevier Science B.V, AII rights reserved.
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The biocontrol strain CHA0 of Pseudomonas fluorescens produces small amounts of indole-3-acetic acid via the tryptophan side chain oxidase and the tryptophan transaminase pathways. A recombinant plasmid (pME3468) expressing the tryptophan monooxygenase pathway was introduced into strain CHA0; this resulted in elevated synthesis of indole-3-acetic acid in vitro, especially after addition of -tryptophan. In natural soil, strain CHA0/pME3468 increased fresh root weight of cucumber by 17-36%, compared to the effect of strain CHA0; root colonization was about 106 cells per g of root. However, both strains gave similar protection of cucumber against Pythium ultimum. In autoclaved soil, at 6×107 cells per g of root, strain CHA0 stimulated growth of roots and shoots, whereas strain CHA0/pME3468 caused root stunting and strong reduction of plant weight. These results are in agreement with the known effects of exogenous indole-3-acetic acid on plant roots and suggest that in the system examined, indole-3-acetic acid does not contribute to the biocontrol properties of strain CHA0.
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Purpose/Objective: Protective CD8+ T cell responses rely on TCRdependent recognition of immunogenic peptides presented by MHC I. Cytolytic T lymphocytes directed against self/tumor antigens express TCRs of lower affinity/avidity than pathogen-derived T lymphocytes and elicit less protective immune responses due to mechanisms of central and peripheral tolerance. Anti-tumor T cell reactivity can be improved by increasing the TCR-pMHC affinity within physiological limits, while intriguingly further increase in the supraphysiological range (KD < 1 lM) leads to drastic functional declines. We aim at identifying the molecular mechanisms underlying the loss of T cell responsiveness associated with supraphysiological TCRpMHC affinities in order to improve effectiveness of TCR-engineered T cells used in adoptive cell transfer (ACT) cancer immunotherapy. Materials and methods: Using a panel of human CD8+ T cells engineered with TCRs of incremental affinity for the HLA-A2-resticted tumor cancer testis antigen NY-ESO-1, we performed comparative gene expression microarray and TCR-mediated signaling analysis together with membrane receptors level analysis. Results: As compared to cells expressing TCR affinities generating optimal function (KD from 5to 1 lM), those with supraphysiological affinity (KD from 1 lM to 15 nM) had an overall reduced expression of genes implied in signaling, cell activation and proliferation, and showed impaired proximal and distal TCR signaling capacity. This correlated with a decline in surface expression of CD8b, CD28 and activatory TNFR superfamily members. Importantly, expression of inhibitory receptor PD-1 and SHP-1 phosphatase was upregulated in a TCR affinity-dependent manner. Consequently, PD-L1 and SHP-1 blockade restored the function of T cells with high TCRs affinity. Moreover, SHP-1 inhibition also augmented functional efficacy of T cells with TCRs of optimal affinity. Conclusions: Our findings indicate that TCR affinity-associated regulatory mechanisms control T cells responsiveness at various levels to limit potential auto-reactive cytotoxic effects. They also support the development of ACT therapies combined with blockade of inhibitory molecules such as SHP-1 to enhance effectiveness of T cell immunotherapy.
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During recovery from a maximal or submaximal aerobic exercise, augmentation of central (aortic) systolic pressure by reflected pressure waves is blunted in healthy humans. However, the extent to which reflected pressure waves modify the central pulse in diastole in these conditions remains unknown. We evaluated systolic and diastolic central reflected waves in 11 endurance-trained athletes on recovery from a maximal running test on a treadmill (treadmill-max) and a 4000 m run in field conditions. On both occasions in each subject, the radial pulse was recorded with applanation tonometry in the resting preexercise state and then 5, 15, 25, 35, and 45 min after exercise termination. From the central waveform, as reconstructed by application of a generalized transfer function, we computed a systolic (AIx) and a diastolic index (AId) of pressure augmentation by reflections. At 5 min, both indices were below preexercise. At further time-points, AIx remained low, while AId progressively increased, to overshoot above preexercise at 45 min. The same behavior was observed with both exercise types. Beyond the first few minutes of recovery following either maximal or submaximal aerobic exercise, reflected waves selectively augment the central pressure pulse in diastole, at least in endurance-trained athletes.