Uma revisão bibliográfica sobre a utilização do termo paradigma em publicações científicas da área da saúde

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Comparing Near-infrared Conventional Diffuse Reflectance Spectroscopy And Hyperspectral Imaging For Determination Of The Bulk Properties Of Solid Samples By Multivariate Regression: Determination Of Mooney Viscosity And Plasticity Indices Of Natural Rubber.

Conventional reflectance spectroscopy (NIRS) and hyperspectral imaging (HI) in the near-infrared region (1000-2500 nm) are evaluated and compared, using, as the case study, the determination of relevant properties related to the quality of natural rubber. Mooney viscosity (MV) and plasticity indices (PI) (PI0 - original plasticity, PI30 - plasticity after accelerated aging, and PRI - the plasticity retention index after accelerated aging) of rubber were determined using multivariate regression models. Two hundred and eighty six samples of rubber were measured using conventional and hyperspectral near-infrared imaging reflectance instruments in the range of 1000-2500 nm. The sample set was split into regression (n = 191) and external validation (n = 95) sub-sets. Three instruments were employed for data acquisition: a line scanning hyperspectral camera and two conventional FT-NIR spectrometers. Sample heterogeneity was evaluated using hyperspectral images obtained with a resolution of 150 × 150 μm and principal component analysis. The probed sample area (5 cm(2); 24,000 pixels) to achieve representativeness was found to be equivalent to the average of 6 spectra for a 1 cm diameter probing circular window of one FT-NIR instrument. The other spectrophotometer can probe the whole sample in only one measurement. The results show that the rubber properties can be determined with very similar accuracy and precision by Partial Least Square (PLS) regression models regardless of whether HI-NIR or conventional FT-NIR produce the spectral datasets. The best Root Mean Square Errors of Prediction (RMSEPs) of external validation for MV, PI0, PI30, and PRI were 4.3, 1.8, 3.4, and 5.3%, respectively. Though the quantitative results provided by the three instruments can be considered equivalent, the hyperspectral imaging instrument presents a number of advantages, being about 6 times faster than conventional bulk spectrometers, producing robust spectral data by ensuring sample representativeness, and minimizing the effect of the presence of contaminants.

Upper limit on the diffuse flux of ultrahigh energy tau neutrinos from the Pierre Auger Observatory

The surface detector array of the Pierre Auger Observatory is sensitive to Earth-skimming tau neutrinos that interact in Earth's crust. Tau leptons from nu(tau) charged-current interactions can emerge and decay in the atmosphere to produce a nearly horizontal shower with a significant electromagnetic component. The data collected between 1 January 2004 and 31 August 2007 are used to place an upper limit on the diffuse flux of nu(tau) at EeV energies. Assuming an E(nu)(-2) differential energy spectrum the limit set at 90% C. L. is E(nu)(2)dN(nu tau)/dE(nu) < 1: 3 x 10(-7) GeV cm(-2) s(-1) sr(-1) in the energy range 2 x 10(17) eV< E(nu) < 2 x 10(19) eV.

Limit on the diffuse flux of ultrahigh energy tau neutrinos with the surface detector of the Pierre Auger Observatory

Data collected at the Pierre Auger Observatory are used to establish an upper limit on the diffuse flux of tau neutrinos in the cosmic radiation. Earth-skimming nu(tau) may interact in the Earth's crust and produce a tau lepton by means of charged-current interactions. The tau lepton may emerge from the Earth and decay in the atmosphere to produce a nearly horizontal shower with a typical signature, a persistent electromagnetic component even at very large atmospheric depths. The search procedure to select events induced by tau decays against the background of normal showers induced by cosmic rays is described. The method used to compute the exposure for a detector continuously growing with time is detailed. Systematic uncertainties in the exposure from the detector, the analysis, and the involved physics are discussed. No tau neutrino candidates have been found. For neutrinos in the energy range 2x10(17) eV < E(nu)< 2x10(19) eV, assuming a diffuse spectrum of the form E(nu)(-2), data collected between 1 January 2004 and 30 April 2008 yield a 90% confidence-level upper limit of E(nu)(2)dN(nu tau)/dE(nu)< 9x10(-8) GeV cm(-2) s(-1) sr(-1).

Radiation use efficiency increases when the diffuse component of incident radiation is enhanced under shade

Theoretical analyses have shown the radiation use efficiency of maize, soybean, and peanut to increase with a decrease in the level of incident radiation and an increase in the proportion of diffuse radiation. This study compared the growth and radiation use efficiency of Panicum maximum cv. Petrie (green panic) and Bothriochloa insculpta cv. Bisset (creeping bluegrass) beneath shading treatments (birdguard and solarweave shadecloths) with that in full sunlight. A level of incident radiation reduced by 25% under birdguard shadecloth decreased final yield and final leaf area index, but increased canopy leaf nitrogen concentration and radiation use efficiency (19-14%) (compared with the full sun treatment). A similar level of reduced incident radiation under solarweave shadecloth (which provided an increased proportion of diffuse radiation), increased final yield and radiation use efficiency (46-50%). An understanding of the effects of composition of incident radiation on radiation use efficiency of tropical grasses enables more accurate estimation of potential pasture growth in shaded environments. It also has impact upon crop production in glasshouses and greenhouses.

Magnetic resonance imaging (MRI) and diseases of the liver and biliary tract. Part 1. Basic principles, MRI in the assessment of diffuse and focal hepatic disease

Magnetic resonance imaging (MRI) relies on the physical properties of unpaired protons in tissues to generate images. Unpaired protons behave like tiny bar magnets and will align themselves in a magnetic field. Radiofrequency pulses will excite these aligned protons to higher energy states. As they return to their original state, they will release this energy as radio waves. The frequency of the radio waves depends on the local magnetic field and by varying this over a subject, it is possible to build the images we are familiar with. In general, MRI has not been sufficiently sensitive or specific in the assessment of diffuse liver disease for clinical use. However, because of the specific characteristics of fat and iron, it may be useful in the assessment of hepatic steatosis and iron overload. Magnetic resonance imaging is useful in the assessment of focal liver disease, particularly in conjunction with contrast agents. Haemangiomas have a characteristic bright appearance on T-2 weighted images because of the slow flowing blood in dilated sinusoids. Focal nodular hyperplasia (FNH) has a homogenous appearance, and enhances early in the arterial phase after gadolinium injection, while the central scar typically enhances late. Hepatic adenomas have a more heterogenous appearance and also enhance in the arterial phase, but less briskly than FNH. Hepatocellular carcinoma is similar to an adenoma, but typically occurs in a cirrhotic liver and has earlier washout of contrast. The appearance of metastases depends on the underlying primary malignancy. Overall, MRI appears more sensitive and specific than computed tomography with contrast for the detection and evaluation of malignant lesions. (C) 2000 Blackwell Science Asia Pty Ltd.

Diffuse systemic sclerosis and autoimmune hepatitis: a unique association

Autoimmune hepatitis (AIH) is a chronic hepatitis of unknown etiology characterized by continuing hepatocellular necrosis and inflammation that afflicts 100,000 to 200,000 persons in the United States. It is a rare manifestation of systemic sclerosis. Only about nine reports of this association have been previously reported in the literature. Importantly, all cases had the limited clinical form of systemic. The authors describe herein the first report of a patient with diffuse systemic sclerosis who was diagnosed with AIH with positive antimitochondrial antibody and had an excellent response to immunosuppressive drugs. We also briefly review the literature regarding this issue.

Prognostic impact of diffuse large B-cell lymphoma subgroups in patients undergoing autologous SCT

A total of 53 patients aged 18-60 years with highintermediate or high-risk diffuse large B-cell lymphoma (DLBCL) were evaluated to analyze the impact of the cell of origin. Of 53 patients, 16 underwent autologous SCT (ASCT) in first remission and the rest received conventional chemotherapy. Immunohistochemistry was evaluated in 47 cases 17 were of germinal center (GC) origin and 30 were of non-GC origin. There was no survival difference between the two groups. Overall survival (OS) and disease-free survival (DFS) at 3 years were 93 and 83%, respectively, for the 14 patients who underwent ASCT. Their DFS was significantly better than that of patients who achieved CR but did not undergo ASCT. We conclude that ASCT is safe and improves the DFS of high-intermediate and high-risk DLBCL, regardless of the cell of origin. This observation should be confirmed in a larger study.

p63 Protein expression in high risk diffuse large B-cell lymphoma

Background: p63 gene is a p53 homologue that encodes proteins with transactivation, DNA-binding and tetramerisation domains. The isoforms TAp63 and TAp73 transactivate p53 target genes and induce apoptosis, whereas the isoforms Delta Np63 and Delta Np73 lack transactivation and might have dominant-negative effects in p53 family members. p63 is expressed in germinal centre lymphocytes and can be related to the development of the lymphoma, but the prognostic significance of its expression in the survival of patients with diffuse large B-cell lymphoma (DLBCL) remains unclear. Aims: To determine whether quantitative immunohistochemical (IHC) analysis of p63 protein expression correlates with CD10 antigen, Bcl-6 antigen and IRF4 antigen expression and to determine whether p63 is a surrogate predictor of overall survival in high-intermediate and high risk DLBCL populations. Methods: CD10, Bcl-6 and IRF4 expression were retrospectively evaluated by IHC in 73 samples of high intermediate and high risk DLBCL and were used to divide the lymphomas into subgroups of germinal centre B-celllike (GCB) and activate B-cell-like (ABC) DLBCL. Similarly, p63 expression was evaluated by IHC and the results were compared with subgroups of DLBCL origin and with the survival rates for these patients. Results: p63 was expressed in more than 50% of malignant cells in 11 patients and did not show correlation with subgroups of GCB-like DLBCL or ABC-like DLBCL, but p63(+) patients had better disease-free survival (DFS) than those who were negative (p = 0.01). Conclusions: p63(+) high-intermediate and high risk DLBCL patients have a better DFS than negative cases.

A prognostic score for AIDS-related diffuse large B-cell lymphoma in Brazil

The aim of this study was to evaluate a prognostic score for aids-related lymphoma (ARL). A retrospective study of 104 patients with ARL treated between January 1999 and December 2007 was conducted. Diffuse large B-cell lymphoma (DLBC) was the most observed histological type (79.8%). The median CD4 lymphocyte count at lymphoma diagnosis was 125 cells per microliter. Treatment response could be evaluated in 83 (79.8%) patients, and 38 (45.8%) reached complete remission (CR); overall response rate was 51.8% (95 CI = 38.5-65.1%). After a median follow-up of 48 months, the 4-year overall survival (OS) rate among all patients was 35.8%, with a median survival time of 9.7 months (95% CI = 5.5-13.9 months). The survival risk factors observed in multivariate analysis (previous AIDS and high-intermediate/high international prognostic index (IPI)) were combined to construct a risk score, which divided the whole patient population in three distinct groups as low, intermediate, and high risk. When this score was applied to DLBC patients, a clear distinction in response rates and in OS could be demonstrated. Median disease-free survival (DFS) for patients that achieved CR was not reached, and DFS in 4 years was 83.0%. Our results show that the reduced OS observed could be explained by poor immune status with advanced stage of disease seen in our population of HIV-positive patients. Further studies will be needed to clarify the role of different treatment approaches for ARL in the setting of marked immunosuppression and to identify a group of patients to whom intensive therapy could be performed with a curative intent.

Early Increase in Myocardial Perfusion After Stem Cell Therapy in Patients Undergoing Incomplete Coronary Artery Bypass Surgery

Incomplete revascularization is associated with worse long-term outcomes. Autologous bone marrow cells (BMC) have recently been tested in patients with severe coronary artery disease. We tested the hypothesis that intramyocardial injection of autologous BMC increases myocardial perfusion in patients undergoing incomplete coronary artery bypass grafting (CABG). Twenty-one patients (19 men), 59 +/- 7 years old, with limiting angina and multivessel coronary artery disease (CAD), not amenable to complete CABG were enrolled. BMC were obtained prior to surgery, and the lymphomonocytic fraction separated by density gradient centrifugation. During surgery, 5 mL containing 2.1 +/- 1.3 x 10(8) BMC (CD34+ = 0.8 +/- 0.3%) were injected in the ischemic non-revascularized myocardium. Myocardial perfusion was assessed by magnetic resonance imaging (MRI) at baseline and 1 month after surgery. The increase in myocardial perfusion was compared between patients with < 50% (group A, n = 11) with that of patients with > 50% (group B, n = 10) of target vessels (stenosis a parts per thousand yenaEuro parts per thousand 70%) successfully bypassed. Injected myocardial segments included the inferior (n = 12), anterior (n = 7), and lateral (n = 2) walls. The number of treated vessels (2.3 +/- 0.8) was significantly smaller than the number of target vessels (4.2 +/- 1.0; P < 0.0001). One month after surgery, cardiac MRI showed a similar reduction (%) in the ischemic score of patients in group A (72.5 +/- 3.2), compared to patients in group B (78.1 +/- 3.2; P = .80). Intramyocardial injection of autologous BMC may help increase myocardial perfusion in patients undergoing incomplete CABG, even in those with fewer target vessels successfully treated. This strategy may be an adjunctive therapy for patients suffering from a more advanced (diffuse) CAD not amenable for complete direct revascularization.