982 resultados para Nanometric ranges
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The diversity and community structures of symbiotic dinoflagellates are described from reef invertebrates in southern and central provinces of the Great Barrier Reef (GBR), Australia, and Zamami Island, Okinawa, Japan. The symbiont assemblages from region to region were dominated by Clade C Symbiodinium spp. and consisted of numerous host-specific and/or rare types (specialists), and several types common to many hosts (generalists). Prevalence in the host community among certain host-generalist symbionts differed between inshore and offshore environments, across latitudinal (central versus southern GBR) gradients, and over wide geographic ranges (GBR versus Okinawa). One particular symbiont (C3h) from the GBR had a dramatic shift in dominance. Its prevalence ranged from being extremely rare, or absent on high-latitude reefs to dominating the scleractinian diversity on a mid-latitude inshore reef. These changes occurred among coral fauna whose larvae must acquire symbionts from environmental sources (horizontal symbiont acquisition). Such differences did not occur among 'vertical transmitters' such as Porites spp., Montipora spp. and pocilloporids (corals that directly transmit symbionts to their offspring) or among those hosts displaying 'horizontal acquisition', but that associate with specific symbionts. Most host-specialized types were found to be characteristic of a particular geographic region (i.e. Okinawa versus Central GBR versus Southern GBR). The mode of symbiont acquisition may play an important role in how symbiont composition may shift in west Pacific host communities in response to climate change. There is no indication that recent episodes of mass bleaching have provoked changes in host-symbiont combinations from the central GBR.
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Analytical and bioanalytical methods of high-performance liquid chromatography with fluorescence detection (HPLC-FLD) were developed and validated for the determination of chloroaluminum phthalocyanine in different formulations of polymeric nanocapsules, plasma and livers of mice. Plasma and homogenized liver samples were extracted with ethyl acetate, and zinc phthalocyanine was used as internal standard. The results indicated that the methods were linear and selective for all matrices studied. Analysis of accuracy and precision showed adequate values, with variations lower than 10% in biological samples and lower than 2% in analytical samples. The recoveries were as high as 96% and 99% in the plasma and livers, respectively. The quantification limit of the analytical method was 1.12 ng/ml, and the limits of quantification of the bioanalytical method were 15 ng/ml and 75 ng/g for plasma and liver samples, respectively. The bioanalytical method developed was sensitive in the ranges of 15-100 ng/ml in plasma and 75-500 ng/g in liver samples and was applied to studies of biodistribution and pharmacokinetics of AlClPc. (C) 2011 Elsevier B.V. All rights reserved.
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The trans-[RUCl(2)(L)(4)], trans-[Ru(NO)Cl (L)(4)](PF(6))(2) (L = isonicotinamide and 4-acetylpyridine) and trans-[Ru(NO)(OH)(py)(4)]Cl(2) (py = pyridine) complexes have been prepared and characterized by elemental analysis, UV-visible, infrared, and (1)H NMR spectroscopies, and cyclic voltammetry. The MLCT band energies of trans-[RUCl(2)(L)(4) increase in the order 4-acpy < isn < py. The reduction potentials of trans-[RuCl(2)(L)(4)] and trans-[Ru(NO)Cl(L)(4)](2+) increase in the order py < isn < 4-acpy. The stretching band frequency. v(NO), of the nitrosyl complexes ranges from 1913 to 1852 cm(-1) indicating a nitrosonium character for the NO ligand. Due to the large pi-acceptor ability of the equatorial ligands, the coordinated water is much more acidic in the water soluble trans-[Ru(NO)(H(2)O)(py)(4)](3+) than in trans-[Ru(NO)(H(2)O)(NH(3))(4)](3+) (C) 2009 Elsevier B.V. All rights reserved.
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This paper reports a parametric investigation and development of grinding technologies for micro aspherical mould inserts using parallel grinding method. The parametric investigation revealed that at nanometric scale the undeformed chip thickness has little influence on the surface finish of ground inserts. The grinding trace spacing has a slightly larger influence on the surface finish. A new technique was developed to true and dress the resin bonded micro wheels with mesh size of #3000, which produced a satisfactory wheel form accuracy and relatively high grain packing density. A form error compensation technique was also developed, with which mould inserts of submicron form accuracy were consistently produced. Using the developed technologies, micro aspherical inserts of diameters ranging from 200 mu m to 1000 mu m with surface finish of around 10 nm and form error of similar to 0.2-0.4 mu m were successfully fabricated. (c) 2005 Elsevier Inc. All rights reserved.
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Introduction: Quantitative computed tomography (qCT)-based assessment of total lung weight (M(lung)) has the potential to differentiate atelectasis from consolidation and could thus provide valuable information for managing trauma patients fulfilling commonly used criteria for acute lung injury (ALI). We hypothesized that qCT would identify atelectasis as a frequent mimic of early posttraumatic ALI. Methods: In this prospective observational study, M(lung) was calculated by qCT in 78 mechanically ventilated trauma patients fulfilling the ALI criteria at admission. A reference interval for M(lung) was derived from 74 trauma patients with morphologically and functionally normal lungs (reference). Results are given as medians with interquartile ranges. Results: The ratio of arterial partial pressure of oxygen to the fraction of inspired oxygen was 560 (506 to 616) mmHg in reference patients and 169 (95 to 240) mmHg in ALI patients. The median reference M(lung) value was 885 (771 to 973) g, and the reference interval for M(lung) was 584 to 1164 g, which matched that of previous reports. Despite the significantly greater median M(lung) value (1088 (862 to 1,342) g) in the ALI group, 46 (59%) ALI patients had M(lung) values within the reference interval and thus most likely had atelectasis. In only 17 patients (22%), Mlung was increased to the range previously reported for ALI patients and compatible with lung consolidation. Statistically significant differences between atelectasis and consolidation patients were found for age, Lung Injury Score, Glasgow Coma Scale score, total lung volume, mass of the nonaerated lung compartment, ventilator-free days and intensive care unit-free days. Conclusions: Atelectasis is a frequent cause of early posttraumatic lung dysfunction. Differentiation between atelectasis and consolidation from other causes of lung damage by using qCT may help to identify patients who could benefit from management strategies such as damage control surgery and lung-protective mechanical ventilation that focus on the prevention of pulmonary complications.
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Background: Extrahepatic portal vein thrombosis (EHPVT) is an important cause of portal hypertension in children. Rex shunt has been used successfully to treat these patients. Methods: We report our experience in 19 infants and children (5 months to 14 years) with HPVT eligible for a mesenteric-portal surgical shunt with left internal jugular vein autograft. Eight children had idiopathic EHPVT, nine had post-umbilical catheterization EHPVT, one had portal vein agenesis, and one had posttransplant EHPVT. Results: It was possible to perform the Rex shunt in all patients except for 8 of 9 cases in the post-umbilical catheterization EHPVT group. A Warren procedure was performed in 4 of those patients and a proximal splenorenal shunt in 1. Current follow-up ranges from 3 to 26 months. Shunt thrombosis occurred in one patient with portal vein agenesis and associated cardiac anomaly. Portal hypertension has significantly improved after surgery. None of our patients have experienced new bleeding episodes until now. Conclusions: The Rex shunt should be considered in the treatment of children with idiopathic EHPVT experiencing repeated gastrointestinal bleeding episodes refractory to endoscopic treatment. Nevertheless, the role of this operation for children with post-umbilical catheterization EHPVT is yet to be clearly evaluated. (C) 2011 Elsevier Inc. All rights reserved.
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The steady-state resonance fluorescence spectrum of a two-level atom driven by a bichromatic field in a broadband squeezed vacuum is studied. When the carrier frequency of the squeezed vacuum is tuned to the frequency of the central spectral line, anomalous spectral features, such as hole burning and dispersive profiles, can occur at the central line. We show that these features appear for wider, and experimentally more convenient, ranges of the parameters than in the case of monochromatic excitation. ?he absence of a coherent spectral component at the central line makes any experimental attempt to observe these features much easier. We also discuss the general features of the spectrum. When the carrier frequency of the squeezed vacuum is tuned to the first odd or even sidebands, the spectrum is asymmetric and only the sidebands an sensitive to phase. For appropriate choices of the phase the linewidths or only the odd or even sidebands can be reduced. A dressed-stale interpretation is provided.
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The popular Newmark algorithm, used for implicit direct integration of structural dynamics, is extended by means of a nodal partition to permit use of different timesteps in different regions of a structural model. The algorithm developed has as a special case an explicit-explicit subcycling algorithm previously reported by Belytschko, Yen and Mullen. That algorithm has been shown, in the absence of damping or other energy dissipation, to exhibit instability over narrow timestep ranges that become narrower as the number of degrees of freedom increases, making them unlikely to be encountered in practice. The present algorithm avoids such instabilities in the case of a one to two timestep ratio (two subcycles), achieving unconditional stability in an exponential sense for a linear problem. However, with three or more subcycles, the trapezoidal rule exhibits stability that becomes conditional, falling towards that of the central difference method as the number of subcycles increases. Instabilities over narrow timestep ranges, that become narrower as the model size increases, also appear with three or more subcycles. However by moving the partition between timesteps one row of elements into the region suitable for integration with the larger timestep these the unstable timestep ranges become extremely narrow, even in simple systems with a few degrees of freedom. As well, accuracy is improved. Use of a version of the Newmark algorithm that dissipates high frequencies minimises or eliminates these narrow bands of instability. Viscous damping is also shown to remove these instabilities, at the expense of having more effect on the low frequency response.
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to test the ability of frequency-doubling technology (FDT) perimetry to detect dysthyroid optic neuropathy (DON). Fifteen eyes of 15 patients with DON and 15 healthy control eyes were studied. Eligible eyes had a diagnosis of DON based on visual field abnormalities on standard automated perimetry and had visual acuity better than 20/30. FDT testing was performed using both the C-20-5 screening test and the C-20 full-threshold test. Normal and DON eyes were compared with regard to FDT mean sensitivity. Sensitivity ranges were 40.0%-86.7% for the screening test, and 53.3%-100.0% (total deviation) and 20.0-93.3 (pattern deviation) for the C-20 threshold test. The corresponding specificity ranges were 86.7-100.0, 33.3-93.3, and 26.7-100.0, respectively. The best sensitivity/specificity ratios were for one abnormal point depressed < 5% in the screening test (86.7%/86.7%), one point depressed < 1% in the total deviation analysis (80.0%/86.7%), and one point depressed < 2% in the pattern deviation analysis (80.0%/86.7%). DON eyes presented significantly lower than normal average sensitivity in the central, pericentral, and peripheral areas. FDT perimetry is a useful screening tool for DON in eyes with normal or only slightly reduced visual acuity.
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Osteonecrosis of the jaw (ONJ), previously an entity associated with radiation therapy to the head and neck, has been observed in patients treated with bisphosphonates. Patients with metastatic breast cancer and myelomatous bone disease, commonly treated with high-potency nitrogen-containing bisphosphonates for a prolonged period of time, have the greatest risk of ONJ development. The reported frequency of ONJ ranges from 0.6% to 6.2% in breast cancer and from 1.7% to 15% in patients with multiple myeloma. Osteonecrosis of the jaw has also been observed in patients with other cancers such as prostate cancer and in benign bone disorders such as osteoporosis and Paget`s disease in which the incidence is low. Risk factors associated with the development of ONJ include dental extractions, length of bisphosphonate treatment, and the type of bisphosphonate used. In this review, we summarize the reported incidence and risk factors associated with ONJ.
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Tuberculous meningitis (TBM) is a severe infection of the central nervous system, particularly in developing countries. Prompt diagnosis and treatment are necessary to decrease the high rates of disability and death associated with TBM. The diagnosis is often time and labour intensive; thus, a simple, accurate and rapid diagnostic test is needed. The adenosine deaminase (ADA) activity test is a rapid test that has been used for the diagnosis of the pleural, peritoneal and pericardial forms of tuberculosis. However, the usefulness of ADA in TBM is uncertain. The aim of this study was to evaluate ADA as a diagnostic test for TBM in a systematic review. A systematic search was performed of the medical literature (MEDLINE, LILACS, Web of Science and EMBASE). The ADA values from TBM cases and controls (diagnosed with other types of meningitis) were necessary to calculate the sensitivity and specificity. Out of a total of 522 studies, 13 were included in the meta-analysis (380 patients with TBM). The sensitivity, specificity and diagnostic odds ratios (DOR) were calculated based on arbitrary ADA cut-off values from 1 to 10 U/l. ADA values from 1 to 4 U/l (sensitivity > 93% and specificity < 80%) helped to exclude TBM; values between 4 and 8 U/l were insufficient to confirm or exclude the diagnosis of TBM (p = 0.07), and values > 8 U/l (sensitivity < 59% and specificity > 96%) improved the diagnosis of TBM (p < 0.001). None of the cut-off values could be used to discriminate between TBM and bacterial meningitis. In conclusion, ADA cannot distinguish between bacterial meningitis and TBM, but using ranges of ADA values could be important to improve TBM diagnosis, particularly after bacterial meningitis has been ruled out. The different methods used to measure ADA and the heterogeneity of data do not allow standardization of this test as a routine.
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This book recognizes the importance of cooperative learning, in contrast to the traditional classroom, as an effective approach to learning. Its coverage of the subject ranges across the educational spectrum, from pre-school years to university, and offers a fresh perspective on a topic that has gained increasing interest worldwide. With contributions from an international panel of leading experts in the field, this engaging text succeeds in providing key insights, linking the theories that underpin the study of group dynamics to their practical application in the classroom. It presents a comprehensive overview of this alternative educative approach, illustrating how cooperative learning experiences can promote socialisation and friendships, and facilitate learning. The editors assemble a range of well-researched essays, covering such aspects as: * The importance of teacher and student interaction * Small group, virtual and non-virtual teaching environments * Assessment practices for measuring the outcomes of individual and group progress * The effect of cooperative learning on relationships amongst students with diverse cultural, social and learning needs. Illustrated with practical examples throughout, this book will be a crucial read for teacher educators, educational psychologists, student teachers, academics and researchers who want to realize the significant potential of cooperative learning in all educational settings.
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BACKGROUND Spontaneously hypertensive rats (SHRs) show increased cardiac sympathetic activity, which could stimulate cardiomyocyte hypertrophy, cardiac damage, and apoptosis. Norepinephrine (NE)induced cardiac oxidative stress seems to be involved in SHR cardiac hypertrophy development. Because exercise training (ET) decreases sympathetic activation and oxidative stress, it may alter cardiac hypertrophy in SHR. The aim of this study was to determine, in vivo, whether ET alters cardiac sympathetic modulation on cardiovascular system and whether a correlation exists between cardiac oxidative stress and hypertrophy. METHODS Male SHRs (15-weeks old) were divided into sedentary hypertensive (SHR, n = 7) and exercise-trained hypertensive rats (SHR-T, n = 7). Moderate ET was performed on a treadmill (5 days/week, 60 min, 10 weeks). After ET, cardiopulmonary reflex responses were assessed by bolus injections of 5-HT. Autoregressive spectral estimation was performed for systolic arterial pressure (SAP) with oscillatory components quantified as low (LF: 0.2-0.75 Hz) and high (HF:0.75-4.0 Hz) frequency ranges. Cardiac NE concentration, lipid peroxidation, antioxidant enzymes activities, and total nitrates/nitrites were determined. RESULTS ET reduced mean arterial pressure, SAP variability (SAP var), LIF of SAP, and cardiac hypertrophy and increased cardiopulmonary reflex responses. Cardiac lipid peroxidation was decreased in trained SHRs and positively correlated with NE concentrations (r= 0.89, P < 0.01) and heart weight/body weight ratio (r= 0.72, P < 0.01), and inversely correlated with total nitrates/nitrites (r= -0.79, P < 0.01). Moreover, in trained SHR, cardiac total nitrates/nitrites were inversely correlated with NE concentrations (r= -0.82, P < 0.01). CONCLUSIONS ET attenuates cardiac sympathetic modulation and cardiac hypertrophy, which were associated with reduced oxidative stress and increased nitric oxide (NO) bioavailability. Am J Hypertens 2008;21:1138-1193 (C) 2008 American Journal of Hypertension, Ltd.
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Selection criteria for lung donation were based on initial experiences with lung transplantation without further studies to improve them, thereby guaranting the best use of donated organs. A definition of an extended criteria donor is therefore required to obtain more lungs to meet the demands of patients awaiting transplantation. Studies have been reviewed for the impact on survival and morbidity of age ranges, oxygen fraction, cause of death, smoking habits, x-ray findings, infection, hepatitis serology and non-heart-beating status, seeking to support physicians to make decisions regarding the use of marginal organs.
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In this study, the photodynamic action of liposomes (LP) and nanocapsules (NC) containing Chloroaluminum phthalocyanine (CIAIPc), on the human melanoma cell (WM 1552C), was assessed. The light source was setup at 672 nm, which corresponds to the maximum absorption wavelength of the CIAIPc. Both colloidal carriers presented size in nanometric scale as well as negative zeta potential. The cellular damage was light dose dependent ranging from 30% of cell death at 70 mJ.cm(-2) to 90% of death at 700 mJ.cm(-2). However, the photocytotoxic effect of LP at 70 mJ.cm(-2) was slightly more efficient to induce cellular death than NC formulation. At 140 mJ.cm(-2), and 700 mJ.cm(-2) both nanocarriers were equally efficient to induce cellular damage. Therefore, in the present work, the maximum phototoxic effect was obtained with 700 mJ.cm(-2) of light dose, in combination with 0.29 mu g.mL(-1) of CIAIPc encapsulated into LP and NC. The cells were also positive to annexin V, after the PDT treatment with LP and NC, showing that one of the mechanisms of cellular death involved is apoptosis. In summary, the potential of LP and NC as a drug delivery system, in Photodynamic Therapy (PDT) against melanoma, has been confirmed using a lower concentration of the photosensitizer and lower light doses than that applied in current protocols. This is an innovative proposal to treat melanoma cell lines that until now have not received the benefit of the PDT protocol for treatment.