Linfomas Double-Hit em casuística de Linfomas Não-Hodgkin B de alto grau: estudo clínico, morfológico, imunoistoquímico e citogenético

Pós-graduação em Patologia - FMB

Chaos control and sensitivity analysis of a double pendulum arm excited by an RLC circuit based nonlinear shaker

In this paper the dynamical interactions of a double pendulum arm and an electromechanical shaker is investigated. The double pendulum is a three degree of freedom system coupled to an RLC circuit based nonlinear shaker through a magnetic field, and the capacitor voltage is a nonlinear function of the instantaneous electric charge. Numerical simulations show the existence of chaotic behavior for some regions in the parameter space and this behaviour is characterized by power spectral density and Lyapunov exponents. The bifurcation diagram is constructed to explore the qualitative behaviour of the system. This kind of electromechanical system is frequently found in robotic systems, and in order to suppress the chaotic motion, the State-Dependent Riccati Equation (SDRE) control and the Nonlinear Saturation control (NSC) techniques are analyzed. The robustness of these two controllers is tested by a sensitivity analysis to parametric uncertainties.

Double-Observer Line Transect Methods: Levels of Independence

Double-observer line transect methods are becoming increasingly widespread, especially for the estimation of marine mammal abundance from aerial and shipboard surveys when detection of animals on the line is uncertain. The resulting data supplement conventional distance sampling data with two-sample mark–recapture data. Like conventional mark–recapture data, these have inherent problems for estimating abundance in the presence of heterogeneity. Unlike conventional mark–recapture methods, line transect methods use knowledge of the distribution of a covariate, which affects detection probability (namely, distance from the transect line) in inference. This knowledge can be used to diagnose unmodeled heterogeneity in the mark–recapture component of the data. By modeling the covariance in detection probabilities with distance, we show how the estimation problem can be formulated in terms of different levels of independence. At one extreme, full independence is assumed, as in the Petersen estimator (which does not use distance data); at the other extreme, independence only occurs in the limit as detection probability tends to one. Between the two extremes, there is a range of models, including those currently in common use, which have intermediate levels of independence. We show how this framework can be used to provide more reliable analysis of double-observer line transect data. We test the methods by simulation, and by analysis of a dataset for which true abundance is known. We illustrate the approach through analysis of minke whale sightings data from the North Sea and adjacent waters.

Perturbative analysis of the triply differential cross section and circular dichroism in photo-double-ionization of He

We extend application of our lowest-order perturbative approach (in electron-electron correlation) for analysis of photo-double-ionization (PDI) of He [A.Y. Istomin et al., J. Phys. B 35, L543 (2002)] to excess energies up to 450 eV and to analysis of circular dichroism. We find that account of electron correlation in the final state to first order provides predictions for the triply differential cross section and circular dichroism that are in reasonable agreement with absolute data for excess energies up to 80 eV. For an excess energy of 450 eV, account of electron correlation in both initial and final states is necessary and the predicted triply differential cross sections are in agreement with absolute data only for large mutual ejection angles. We find that at excess energies of a few tens of eV, the PDI is dominated by the "virtual" knock-out mechanism, while the "direct" (on-shell) knock-out process gives only small contributions for large mutual ejection angles. As a result, we conclude that the circular dichroism effect at these energies originates from the nonzero electron Coulomb phase shifts.

Prefrontal cortex modulation using transcranial DC stimulation reduces alcohol craving: A double-blind, sham-controlled study

Background: Functional neuroimaging studies have shown that specific brain areas are associated with alcohol craving including the dorsolateral prefrontal cortex (DLPFC). We tested whether modulation of DLPFC using transcranial direct current stimulation (tDCS) could alter alcohol craving in patients with alcohol dependence while being exposed to alcohol cues. Methods: We performed a randomized sham-controlled study in which 13 subjects received sham and active bilateral tDCS delivered to DLPFC (anodal left/cathodal right and anodal right/cathodal left). For sham stimulation, the electrodes were placed at the same positions as in active stimulation; however, the stimulator was turned off after 30 s of stimulation. Subjects were presented videos depicting alcohol consumption to increase alcohol craving. Results: Our results showed that both anodal left/cathodal right and anodal right/cathodal left significantly decreased alcohol craving compared to sham stimulation (p < 0.0001). In addition, we found that following treatment, craving could not be further increased by alcohol cues. Conclusions: Our findings showed that tDCS treatment to DLPFC can reduce alcohol craving. These findings extend the results of previous studies using noninvasive brain stimulation to reduce craving in humans. Given the relatively rapid suppressive effect of tDCS and the highly fluctuating nature of alcohol craving, this technique may prove to be a valuable treatment strategy within the clinical setting. (C) 2007 Elsevier Ireland Ltd. All rights reserved.

Percolated non-Newtonian flow for silicone obtained from exfoliated bioinorganic layered double hydroxide intercalated with amino acid

A simple and scalable procedure was used to obtain thin, stable, homogeneous, and easy-to-handle films composed of silicone derived from dimethicones containing dispersed hydrotalcite-type materials previously organo-modified with amino acids. The absence of the typical X-ray pattern of the bioinorganic LDH filler suggested an exfoliation process that was further indirectly evidenced by a drastic change in the rheological behavior, which turned from a quasi-Newtonian behavior for the silicone free of LDH filler to an extensive developed gel-like structure for the nanocomposite derivatives. Visualized by the shear-thinning exponent of the complex viscosity in the low-frequency range, the percolation threshold was evident for filler loading as low as <5 w/W%, suggesting the presence of a largely developed interface between the filler and the polymer. The increase of more than one order of magnitude in viscosity was explained by the rather strong attrition phenomenon between the tethered amino acid anions and the silicone chains. UVB radiation absorption profiles make such bioinorganic polymer nanocomposites potentially applicable in skin protection. Thermo-gravimetric analysis revealed significant improvement in the thermal stability, especially in the final step of the polymer combustion, thus underlining the role of the hybrid material as a thermal retardant agent. (C) 2011 Elsevier B.V. All rights reserved.

Double-Stranded RNA-Activated Protein Kinase Is a Key Modulator of Insulin Sensitivity in Physiological Conditions and in Obesity in Mice

The molecular integration of nutrient-and pathogen-sensing pathways has become of great interest in understanding the mechanisms of insulin resistance in obesity. The double-stranded RNA-dependent protein kinase (PKR) is one candidate molecule that may provide cross talk between inflammatory and metabolic signaling. The present study was performed to determine, first, the role of PKR in modulating insulin action and glucose metabolism in physiological situations, and second, the role of PKR in insulin resistance in obese mice. We used Pkr(-/-) and Pkr(+/+) mice to investigate the role of PKR in modulating insulin sensitivity, glucose metabolism, and insulin signaling in liver, muscle, and adipose tissue in response to a high-fat diet. Our data show that in lean Pkr(-/-) mice, there is an improvement in insulin sensitivity, and in glucose tolerance, and a reduction in fasting blood glucose, probably related to a decrease in protein phosphatase 2A activity and a parallel increase in insulin-induced thymoma viral oncogene-1 (Akt) phosphorylation. PKR is activated in tissues of obese mice and can induce insulin resistance by directly binding to and inducing insulin receptor substrate (IRS)-1 serine307 phosphorylation or indirectly through modulation of c-Jun N-terminal kinase and inhibitor of kappa B kinase beta. Pkr(-/-) mice were protected from high-fat diet-induced insulin resistance and glucose intolerance and showed improved insulin signaling associated with a reduction in c-Jun N-terminal kinase and inhibitor of kappa B kinase beta phosphorylation in insulin-sensitive tissues. PKR may have a role in insulin sensitivity under normal physiological conditions, probably by modulating protein phosphatase 2A activity and serine-threonine kinase phosphorylation, and certainly, this kinase may represent a central mechanism for the integration of pathogen response and innate immunity with insulin action and metabolic pathways that are critical in obesity. (Endocrinology 153:5261-5274, 2012)

Minocycline benefits negative symptoms in early schizophrenia: a randomised double-blind placebo-controlled clinical trial in patients on standard treatment

The onset and early course of schizophrenia is associated with subtle loss of grey matter which may be responsible for the evolution and persistence of symptoms such as apathy, emotional blunting, and social withdrawal. Such 'negative' symptoms are unaffected by current antipsychotic therapies. There is evidence that the antibiotic minocycline has neuroprotective properties. We investigated whether the addition of minocycline to treatment as usual (TAU) for 1 year in early psychosis would reduce negative symptoms compared with placebo. In total, 144 participants within 5 years of first onset in Brazil and Pakistan were randomised to receive TAU plus placebo or minocycline. The primary outcome measures were the negative and positive syndrome ratings using the Positive and Negative Syndrome Scale. Some 94 patients completed the trial. The mean improvement in negative symptoms for the minocycline group was 9.2 and in the placebo group 4.7, an adjusted difference of 3.53 (s.e. 1.01) 95% CI: 1.55, 5.51; p < 0.001 in the intention-to-treat population. The effect was present in both countries. The addition of minocycline to TAU early in the course of schizophrenia predominantly improves negative symptoms. Whether this is mediated by neuroprotective, anti-inflammatory or others actions is under investigation.

A new Comanthera (Eriocaulaceae) from the Espinha double dagger o Range, Minas Gerais, Brazil

We describe and illustrate the new species Comanthera brunnea (Eriocaulaceae: Paepalanthoideae). This species is endemic to the sandy fields of the campos rupestres of the northeastern Espinha double dagger o range in Minas Gerais, Brazil. We compare it with Comanthera suberosa, the morphologically most similar species, and with C. brasiliana, which also has similar features. The morphological variation, habitat, geographic distribution, and conservation status of this new species are discussed.

The Impact of Tacrolimus as Rescue Therapy in Children Using a Double Immunosuppressive Regimen After Heart Transplantation

Background. Organ transplant recipients with refractory rejection or intolerance to the prescribed immunosuppressant may respond to rescue therapy with tacrolimus. We sought to evaluate the clinical outcomes of children undergoing heart transplantation who required conversion from a cyclosporine-based, steroid-free therapy to a tacrolimus-based regimen. Methods. We performed a prospective, observational, cohort study of 28 children who underwent conversion from cyclosporine-based, steroid-free therapy to a tacrolimus-based therapy for refractory or late rejection or intolerance to cyclosporine. Results. There was complete resolution of refractory rejection episodes and adverse side effects in all patients. The incidence rate (X100) of rejection episodes before and after conversion was 7.98 and 2.11, respectively (P <= .0001). There was a 25% mortality rate in patients using tacrolimus after a mean period of 60 months after conversion. Conclusion. Tacrolimus is effective as rescue therapy for refractory rejection and is a therapeutic option for pediatric patients.

Quantum oscillations of spin polarization in a GaAs/AlGaAs double quantum well

5 We employ the circular-polarization-resolved magnetophotoluminescence technique to probe the spin character of electron and hole states in a GaAs/AlGaAs strongly coupled double-quantum-well system. The photoluminescence (PL) intensities of the lines associated with symmetric and antisymmetric electron states present clear out-of-phase oscillations between integer values of the filling factor. and are caused by magnetic-field-induced changes in the population of occupied Landau levels near to the Fermi level of the system. Moreover, the degree of circular polarization of these emissions also exhibits the oscillatory behavior with increasing magnetic field. Both quantum oscillations observed in the PL intensities and in the degree of polarizations may be understood in terms of a simple single-particle approach model. The k . p method was used to calculate the photoluminescence peak energies and the degree of circular polarizations in the double-quantum-well structure as a function of the magnetic field. These calculations prove that the character of valence band states plays an important role in the determination of the degree of circular polarization and, thus, resulting in a magnetic-field-induced change of the polarization sign.

Nebulized 0.5, 2.5 and 5 ml L-epinephrine for post-extubation stridor in children: a prospective, randomized, double-blind clinical trial

Nebulized l-epinephrine has been recommended for the treatment of viral croup. However, the few studies assessing its effect on post-extubation stridor (PES) have shown conflicting results. We compared the efficacy and safety of nebulized l-epinephrine at three different doses for the treatment of PES. We conducted a prospective, randomized, double-blind trial including all consecutive children with a PES score of a parts per thousand yen4 (Westley score). The primary efficacy outcome was change in PES score at 40 min. A reduction of a parts per thousand yen2 points in stridor score was defined as clinically significant. A total of 96 patients were randomly assigned to receive one of three doses of nebulized l-epinephrine upon achieving a PES score of 4 or more following extubation. Stridor score and vital signs were recorded before treatment, and at 20, 40, 60 and 180 min after nebulization. Baseline characteristics were similar among all study groups. No significant difference was detected among the treatments based on change in Westley score by intent-to-treat analysis. In addition, the difference in the number of patients who clinically improved among the treatment groups was not significant (p = 0.54). Patients receiving 5 ml nebulized epinephrine had a significant increase of systolic and diastolic blood pressure at 40 and 180 min. Nebulized l-epinephrine at doses of 0.5, 2.5 and 5 ml demonstrated a lack of dose response in effect on PES and a modestly clinically significant increase in undesired side effects (heart rate and blood pressure) at higher doses.

A Homonuclear Rotational Echo Double-Resonance Method for Measuring Site-Resolved Distance Distributions in I=1/2 Spin Pairs, Clusters, and Multispin Systems

Deutsche Forschungsgemeinschaft [SFB 858]