We study numerically a one-dimensional mixture of spin-1 2 fermions and scalar bosons in the hard... more We study numerically a one-dimensional mixture of spin-1 2 fermions and scalar bosons in the hardcore limit. Considering repulsive fermion-fermion and boson-fermion interactions, we find superfluid and insulator states whose phase diagram is calculated. We determine that given a fermionic density ρF , the insulator states are located at the bosonic densities ρB = 1 − ρF and ρB = 1 − 1 2 ρF , and emerge even in the absence of fermion-fermion coupling. In addition, the boson-fermion repulsion drives quantum phase transitions inside the insulator lobes with ρB = 1/2. Our predictions could be observed in current cold-atom experimental platforms.
The aim of this study is to compare spironolactone versus clonidine as the fourth drug in patient... more The aim of this study is to compare spironolactone versus clonidine as the fourth drug in patients with resistant hypertension in a multicenter, randomized trial. Medical therapy adherence was checked by pill counting. Patients with resistant hypertension (no office and ambulatory blood pressure [BP] monitoring control, despite treatment with 3 drugs, including a diuretic, for 12 weeks) were randomized to an additional 12-week treatment with spironolactone (12.5-50 mg QD) or clonidine (0.1-0.3 mg BID). The primary end point was BP control during office (<140/90 mm Hg) and 24-h ambulatory (<130/80 mm Hg) BP monitoring. Secondary end points included BP control from each method and absolute BP reduction. From 1597 patients recruited, 11.7% (187 patients) fulfilled the resistant hypertension criteria. Compared with the spironolactone group (n=95), the clonidine group (n=92) presented similar rates of achieving the primary end point (20.5% versus 20.8%, respectively; relative risk,...
We study the ground-state phase diagram of boson chains on a 2-period superlattice using the dens... more We study the ground-state phase diagram of boson chains on a 2-period superlattice using the density matrix renormalization group method. New insulators for commensurate densities were found, differentiated by the arrangement of the particles in the unit cell, which was corroborated by analysis of the density versus the potential strength. Also, phase transitions between insulators for ρ ≥ 1 were seen, and a maximum in the behavior of the von Neumann entropy in the critical region was revealed, which suggests a superfluid phase between the insulators.
Objectives: To compare the blood pressure (BP)-lowering efficacy of a chlorthalidone/amiloride co... more Objectives: To compare the blood pressure (BP)-lowering efficacy of a chlorthalidone/amiloride combination pill with losartan, during initial management of stage I hypertension. Methods: In a randomized, double-blind, controlled trial, 655 participants were followed for 18 months in 21 Brazilian academic centers. Trial participants were adult volunteers aged 30-70 years with stage I hypertension (BP 140-159 or 90-99 mmHg) following 3 months of a lifestyle intervention. Participants were randomized to 12.5/2.5 mg of chlorthalidone/amiloride (N ¼ 333) or 50 mg of losartan (N ¼ 322). If BP remained uncontrolled after 3 months, study medication dose was doubled, and if uncontrolled after 6 months, amlodipine (5 and 10 mg) and propranolol (40 and 80 mg twice daily) were added as open-label drugs in a progressive fashion. At the end of follow-up, 609 (93%) participants were evaluated. Results: The difference in SBP during 18 months of follow-up was 2.3 (95% confidence interval: 1.2 to 3.3) mmHg favoring chlorthalidone/amiloride. Compared with those randomized to diuretic, more participants allocated to losartan had their initial dose doubled and more of them used add-on antihypertensive medication. Levels of blood glucose, glycosilated hemoglobin, and incidence of diabetes were no different between the two treatment groups. Serum potassium was lower and serum cholesterol was higher in the diuretic arm. Microalbuminuria tended to be higher in patients with diabetes allocated to losartan (28.5 AE 40.4 versus 16.2 AE 26.7 mg, P ¼ 0.09). Conclusion: Treatment with a combination of chlorthalidone and amiloride compared with losartan yielded a greater reduction in BP. Clinical trials registration number: NCT00971165.
Induction of apoptosis in leukemia cell lines by new copper(II) complexes containing naphthyl gro... more Induction of apoptosis in leukemia cell lines by new copper(II) complexes containing naphthyl groups via interaction with death receptors
We report the results of a theoretical study of structural, electronic, and pressure-induced phas... more We report the results of a theoretical study of structural, electronic, and pressure-induced phase transition properties in ZnTe. Total energies of several high-pressure polymorphs are calculated using the density functional theory ͑DFT͒ formalism under the nonlocal approximation. Thermal effects are included by means of a nonempirical Debye-like model. In agreement with optical absorption data, the lowest direct gap of the zinc blende polymorph is found to follow a nonlinear pressure dependence that turns into linear behavior when expressed in terms of the decrease in the lattice parameter. The pressure stability ranges of cubic ͑zinc blende and rocksalt͒, trigonal ͑cinnabar͒, and orthorhombic ͑Cmcm͒ polymorphs are computed at static and room temperature conditions. Our calculations agree with the experimental and theoretical reported zinc blende →cinnabar→Cmcm pressure-induced phase sequence. Linear and bulk compressibilities are evaluated for the four polymorphs and reveal an anisotropic behavior of the cinnabar structure, which contrasts with the cubiclike compression of its shortest Zn-Te bonds. The qualitative trend shows a crystal that becomes relatively less compressible in the high-pressure phases.
Resistant hypertension (RH) is characterized by blood pressure above 140 × 90 mm Hg, despite the ... more Resistant hypertension (RH) is characterized by blood pressure above 140 × 90 mm Hg, despite the use, in appropriate doses, of three antihypertensive drug classes, including a diuretic, or the need of four classes to control blood pressure. Resistant hypertension patients are under a greater risk of presenting secondary causes of hypertension and may be benefited by therapeutical approach for this diagnosis. However, the RH is currently little studied, and more knowledge of this clinical condition is necessary. In addition, few studies had evaluated this issue in emergent countries. Therefore, we proposed the analysis of specific causes of RH by using a standardized protocol in Brazilian patients diagnosed in a center for the evaluation and treatment of hypertension. The management of these patients was conducted with the application of a preformulated protocol which aimed at the identification of the causes of resistant hypertension in each patient through management standardizatio...
The equations of state and phase diagrams of the cubic spinel and two high-pressure polymorphs of... more The equations of state and phase diagrams of the cubic spinel and two high-pressure polymorphs of MgAl 2 O 4 have been investigated up to 65 GPa using density functional theory, the space-filling polyhedral partition of the unit cell, and the static approximation. Energy-volume curves have been obtained for the spinel phase, the recently observed calcium ferrite-type and calcium titanite-type phases, and the MgOϩ␣-Al 2 O 3 mixture. Zero-pressure unit lengths and compressibilities are well described by the theoretical model, that predicts static bulk moduli about 215 GPa for all the high-pressure forms. Computed equations of state are also in good agreement with the most recent experimental data for all compounds and polymorphs considered. We do not find a continuous pressure-induced phase sequence but the static simulations predict that the oxide mixture, the ferrite phase, and the titanite phase become more stable than the spinel form at 15, 35, and 62 GPa, respectively. A microscopic analysis in terms of polyhedral and bond compressibilities leads to identify the ionic displacements accompanying the phase transformations and to an appealing interpretation of the spinel response to compression.
Visible and Infrared Optical Absorption and Electron Paramagnetic Resonance (EPR) techniques have... more Visible and Infrared Optical Absorption and Electron Paramagnetic Resonance (EPR) techniques have been used to characterize the intrinsic defects in sillenite type crystals: nominally pure Bi12TiO20 (BTO) and doped with vanadium (BTO:V). Optical quality crystals, with the composition Bi12.04±0.08Ti0.76±0.07V0.16±0.02O20, have been grown. Results obtained by these different techniques have shown unambiguously the 5+ valence state of the vanadium ion in BTO:V crystals. In pure BTO samples, the EPR and optical spectra show strong evidence of the presence of the intrinsic defect BiM 3+ + ho + , which consists of a hole h + , mainly located on the oxygen neighbors of the tetrahedrally coordinated Bi 3+ ion. After doping with vanadium, results have shown that the characteristic bands, associated to this hole defect center, disappear, suggesting its transformation in single Bi 3+. Anisotropy of the EPR spectra , at 20 K, is related to Fe 3+ impurities.
In this paper, electron paramagnetic resonance, photoluminescence ͑PL͒ emission, and quantum mech... more In this paper, electron paramagnetic resonance, photoluminescence ͑PL͒ emission, and quantum mechanical calculations were used to observe and understand the structural order-disorder of CaTiO 3 , paying special attention to the role of oxygen vacancy. The PL phenomenon at room temperature of CaTiO 3 is directly influenced by the presence of oxygen vacancies that yield structural order-disorder. These oxygen vacancies bonded at Ti and/or Ca induce new electronic states inside the band gap. Ordered and disordered CaTiO 3 was obtained by the polymeric precursor method.
These experiments assessed the hemodynamic and aquaretic effects of an arginine vasopressin (AVP)... more These experiments assessed the hemodynamic and aquaretic effects of an arginine vasopressin (AVP) antagonist with dual V1V2-receptor inhibiting properties in rats with congestive heart failure resulting from ischemic cardiomyopathy. The compound d(CH2)5-D-Tyr(Et)VAVP was used in these studies. Rats with limited or extensive myocardial infarcts (i.e., with less than 50% or greater than 66% necrosis of the left ventricular wall, respectively, induced by left coronary ligation) and sham-operated controls received the AVP antagonist (100 micrograms/kg i.v.) 4 weeks later. This agent produced an 18% increase in cardiac output (p less than 0.05) and 13% decrease in systemic vascular resistance in the severely damaged rats, both changes being significantly different from those seen in the normal controls or the rats with limited infarcts. All animals exhibited increases in urinary output of 4-10-fold over baseline. We conclude that the hemodynamic and renal effects of this agent are benefi...
Crystalline and quasi-amorphous PZT and PZT:X (X = Ca, Sr and Ba) powders were obtained by the po... more Crystalline and quasi-amorphous PZT and PZT:X (X = Ca, Sr and Ba) powders were obtained by the polymeric precursor method. Electron paramagnetic resonance (EPR) and photoluminescence (PL) data suggest that the presence of order-disorder within the lattice network, i.e., the appearance of symmetrybreaking processes that give rise to non-ideal octahedra and networks of dodecahedral clusters, is an essential factor for the occurrence of PL. Measurements of PL indicate that the shallow defects in the band gap enhance blue light emission.
Background: The activity of the renin-angiotensin-aldosterone system (RAAS) is directly related t... more Background: The activity of the renin-angiotensin-aldosterone system (RAAS) is directly related to overweight and sedentary lifestyles, both of which are associated with hypertension. Aerobic exercise helps control blood pressure (BP) by acting on mechanisms of blood pressure regulation, such as plasma renin activity (PRA). Objective: To assess the effect of aerobic exercise on plasma renin activity in overweight hypertensive patients. Methods: Blood pressure, serum biochemistry and anthropometric parameters of twenty subjects were measured before and after a 16-week exercise training program, three days a week, at 60-80% of maximal heart rate. Data were expressed as mean ± standard deviation or median and interquartile range and analyzed using the student's t-test, Mann-Whitney test, and ANOVA (p < 0.05). Results: Mean age of the study population was 57 ± 7.0, and mean body mass index was 30 ± 3.5 kg/m 2. The aerobic training decreased body fat (35 ± 7.8 to 30 ± 5.6 %), heart rate (HR) (80 ± 10.4 to 77 ± 8.5 bpm), and pulse pressure (PP) (50 ± 11.8 to 46 ± 10.0 mmHg) (p < 0.05), but not plasma renin activity, which ranged from 0.8 (0.45-2.0) to 1.45 (0.8-2.15) ηg/ml/h (p = 0.055). The group that achieved a reduction in waist circumference (WC) (n = 8) experienced also a reduction in systolic BP and PP (p < 0.05). In the group without reduction in WC, none of the BP variables changed. Plasma renin activity (PRA) was not associated with any variable studied. Aerobic training was associated with a decrease in PP in the study group as a whole and with a decrease in systolic BP in the subgroup who experienced a decrease in waist circumference. Conclusion: The aerobic exercise training failed to reduce plasma renin activity in overweight hypertensive patients.
Em sintonia com a tendência científica mundial e a orientação da Associação Médica Brasileira, as... more Em sintonia com a tendência científica mundial e a orientação da Associação Médica Brasileira, as IV Diretrizes Brasileiras de Hipertensão fundamentam suas orientações segundo Graus de Recomendação baseados em níveis de evidência dos estudos clínicos de referência: Grau A-grandes ensaios clínicos aleatorizados e metanálises. Grau B-estudos clínicos e observacionais bem desenhados. Grau C-relatos e séries de casos. Grau D-publicações baseadas em consensos e opiniões de especialistas.
vacancies were identified in disordered SrTiO 3 powders prepared by the polymeric precursor metho... more vacancies were identified in disordered SrTiO 3 powders prepared by the polymeric precursor method, based on experimental measurements by x-ray absorption near edge structure spectroscopy. The paramagnetic complex states of ͓TiO 5 • V O • ͔ and ͓SrO 11 • V O • ͔ with unpaired electrons were confirmed by electron paramagnetic resonance spectroscopy. The disordered powders showed strong photoluminescence at room temperature. Structural defects of disordered powders, in terms of band diagram, density of states, and electronic charges, were interpreted using high-level quantum mechanical calculations in the density functional framework. The four periodic models used here were consistent with the experimental data and explained the presence of photoluminescence.
We discuss how positions of critical points of the three-dimensional Bose-Hubbard model can be ac... more We discuss how positions of critical points of the three-dimensional Bose-Hubbard model can be accurately obtained from variance of the on-site atom number operator, which can be experimentally measured. the idea that we explore is that the derivative of the variance, with respect to the parameter driving the transition, has a pronounced maximum close to critical points. We show that Quantum Monte Carlo studies of this maximum lead to precise determination of critical points for the superfluid-Mott insulator transition in systems with mean number of atoms per lattice site equal to one, two, and three. We also extract from such data the correlation-length critical exponent through the finite-size scaling analysis and discuss how the derivative of the variance can be reliably computed from numerical data for the variance. the same conclusions apply to the derivative of the nearest-neighbor correlation function, which can be obtained from routinely measured time-of-flight images.
Estudiamos el transporte electronico a traves de un hilo cuantico (QW), descrito por medio de una... more Estudiamos el transporte electronico a traves de un hilo cuantico (QW), descrito por medio de una cadena tight-binding, con un punto cuantico (QD) inmerso. Obtenemos la conductancia con una fuerte resonancia Fano; la densidad de estados muestra que este comportamiento esta asociado con una renormalizacion del nivel de energia del QD �Ef , debida a una interaccion de muchos cuerpos, entorno al extremo de la banda de conduccion (CB), fuertemente hibridizada con los picos de Van Hove en la densidad de estados de la cadena unidimensional. Obtenemos que esta resonancia Fano es termicamente activada, arriba de la temperatura de Kondo; esto es debido a un proceso de interferencia cuantica entre la CB y un canal termicamente activado, originado por el QD resonante entorno a un extremo de la CB. Nuestros resultados estan en acuerdo cualitativo con un reporte experimental para un T-coupled QD.
In this work we present a generalization of our previous work of the X−boson approach to the peri... more In this work we present a generalization of our previous work of the X−boson approach to the periodic Anderson model (PAM), adequate to study a novel class of intermetallic 4f and 5f orbitals materials: the topological Kondo insulators, whose paradigmatic material is the compound SmB6. For simplicity, we consider a version of the PAM on a 2D square lattice, adequate to describe Ce−based compounds in two dimensions. The starting point of the model is the 4f − Ce ions orbitals, with J = 5/2 multiplet, in the presence of spin-orbit coupling. Our technique works well for all of the parameters of the model and avoids the unwanted phase transitions of the slave boson mean field theory. We present a critical comparison of our results with those of the usual slave boson method, that has been intensively used to describe this class of materials. We also obtain a new valence first order transition which we attribute to the k dependence of the hybridization.
We study numerically a one-dimensional mixture of spin-1 2 fermions and scalar bosons in the hard... more We study numerically a one-dimensional mixture of spin-1 2 fermions and scalar bosons in the hardcore limit. Considering repulsive fermion-fermion and boson-fermion interactions, we find superfluid and insulator states whose phase diagram is calculated. We determine that given a fermionic density ρF , the insulator states are located at the bosonic densities ρB = 1 − ρF and ρB = 1 − 1 2 ρF , and emerge even in the absence of fermion-fermion coupling. In addition, the boson-fermion repulsion drives quantum phase transitions inside the insulator lobes with ρB = 1/2. Our predictions could be observed in current cold-atom experimental platforms.
The aim of this study is to compare spironolactone versus clonidine as the fourth drug in patient... more The aim of this study is to compare spironolactone versus clonidine as the fourth drug in patients with resistant hypertension in a multicenter, randomized trial. Medical therapy adherence was checked by pill counting. Patients with resistant hypertension (no office and ambulatory blood pressure [BP] monitoring control, despite treatment with 3 drugs, including a diuretic, for 12 weeks) were randomized to an additional 12-week treatment with spironolactone (12.5-50 mg QD) or clonidine (0.1-0.3 mg BID). The primary end point was BP control during office (<140/90 mm Hg) and 24-h ambulatory (<130/80 mm Hg) BP monitoring. Secondary end points included BP control from each method and absolute BP reduction. From 1597 patients recruited, 11.7% (187 patients) fulfilled the resistant hypertension criteria. Compared with the spironolactone group (n=95), the clonidine group (n=92) presented similar rates of achieving the primary end point (20.5% versus 20.8%, respectively; relative risk,...
We study the ground-state phase diagram of boson chains on a 2-period superlattice using the dens... more We study the ground-state phase diagram of boson chains on a 2-period superlattice using the density matrix renormalization group method. New insulators for commensurate densities were found, differentiated by the arrangement of the particles in the unit cell, which was corroborated by analysis of the density versus the potential strength. Also, phase transitions between insulators for ρ ≥ 1 were seen, and a maximum in the behavior of the von Neumann entropy in the critical region was revealed, which suggests a superfluid phase between the insulators.
Objectives: To compare the blood pressure (BP)-lowering efficacy of a chlorthalidone/amiloride co... more Objectives: To compare the blood pressure (BP)-lowering efficacy of a chlorthalidone/amiloride combination pill with losartan, during initial management of stage I hypertension. Methods: In a randomized, double-blind, controlled trial, 655 participants were followed for 18 months in 21 Brazilian academic centers. Trial participants were adult volunteers aged 30-70 years with stage I hypertension (BP 140-159 or 90-99 mmHg) following 3 months of a lifestyle intervention. Participants were randomized to 12.5/2.5 mg of chlorthalidone/amiloride (N ¼ 333) or 50 mg of losartan (N ¼ 322). If BP remained uncontrolled after 3 months, study medication dose was doubled, and if uncontrolled after 6 months, amlodipine (5 and 10 mg) and propranolol (40 and 80 mg twice daily) were added as open-label drugs in a progressive fashion. At the end of follow-up, 609 (93%) participants were evaluated. Results: The difference in SBP during 18 months of follow-up was 2.3 (95% confidence interval: 1.2 to 3.3) mmHg favoring chlorthalidone/amiloride. Compared with those randomized to diuretic, more participants allocated to losartan had their initial dose doubled and more of them used add-on antihypertensive medication. Levels of blood glucose, glycosilated hemoglobin, and incidence of diabetes were no different between the two treatment groups. Serum potassium was lower and serum cholesterol was higher in the diuretic arm. Microalbuminuria tended to be higher in patients with diabetes allocated to losartan (28.5 AE 40.4 versus 16.2 AE 26.7 mg, P ¼ 0.09). Conclusion: Treatment with a combination of chlorthalidone and amiloride compared with losartan yielded a greater reduction in BP. Clinical trials registration number: NCT00971165.
Induction of apoptosis in leukemia cell lines by new copper(II) complexes containing naphthyl gro... more Induction of apoptosis in leukemia cell lines by new copper(II) complexes containing naphthyl groups via interaction with death receptors
We report the results of a theoretical study of structural, electronic, and pressure-induced phas... more We report the results of a theoretical study of structural, electronic, and pressure-induced phase transition properties in ZnTe. Total energies of several high-pressure polymorphs are calculated using the density functional theory ͑DFT͒ formalism under the nonlocal approximation. Thermal effects are included by means of a nonempirical Debye-like model. In agreement with optical absorption data, the lowest direct gap of the zinc blende polymorph is found to follow a nonlinear pressure dependence that turns into linear behavior when expressed in terms of the decrease in the lattice parameter. The pressure stability ranges of cubic ͑zinc blende and rocksalt͒, trigonal ͑cinnabar͒, and orthorhombic ͑Cmcm͒ polymorphs are computed at static and room temperature conditions. Our calculations agree with the experimental and theoretical reported zinc blende →cinnabar→Cmcm pressure-induced phase sequence. Linear and bulk compressibilities are evaluated for the four polymorphs and reveal an anisotropic behavior of the cinnabar structure, which contrasts with the cubiclike compression of its shortest Zn-Te bonds. The qualitative trend shows a crystal that becomes relatively less compressible in the high-pressure phases.
Resistant hypertension (RH) is characterized by blood pressure above 140 × 90 mm Hg, despite the ... more Resistant hypertension (RH) is characterized by blood pressure above 140 × 90 mm Hg, despite the use, in appropriate doses, of three antihypertensive drug classes, including a diuretic, or the need of four classes to control blood pressure. Resistant hypertension patients are under a greater risk of presenting secondary causes of hypertension and may be benefited by therapeutical approach for this diagnosis. However, the RH is currently little studied, and more knowledge of this clinical condition is necessary. In addition, few studies had evaluated this issue in emergent countries. Therefore, we proposed the analysis of specific causes of RH by using a standardized protocol in Brazilian patients diagnosed in a center for the evaluation and treatment of hypertension. The management of these patients was conducted with the application of a preformulated protocol which aimed at the identification of the causes of resistant hypertension in each patient through management standardizatio...
The equations of state and phase diagrams of the cubic spinel and two high-pressure polymorphs of... more The equations of state and phase diagrams of the cubic spinel and two high-pressure polymorphs of MgAl 2 O 4 have been investigated up to 65 GPa using density functional theory, the space-filling polyhedral partition of the unit cell, and the static approximation. Energy-volume curves have been obtained for the spinel phase, the recently observed calcium ferrite-type and calcium titanite-type phases, and the MgOϩ␣-Al 2 O 3 mixture. Zero-pressure unit lengths and compressibilities are well described by the theoretical model, that predicts static bulk moduli about 215 GPa for all the high-pressure forms. Computed equations of state are also in good agreement with the most recent experimental data for all compounds and polymorphs considered. We do not find a continuous pressure-induced phase sequence but the static simulations predict that the oxide mixture, the ferrite phase, and the titanite phase become more stable than the spinel form at 15, 35, and 62 GPa, respectively. A microscopic analysis in terms of polyhedral and bond compressibilities leads to identify the ionic displacements accompanying the phase transformations and to an appealing interpretation of the spinel response to compression.
Visible and Infrared Optical Absorption and Electron Paramagnetic Resonance (EPR) techniques have... more Visible and Infrared Optical Absorption and Electron Paramagnetic Resonance (EPR) techniques have been used to characterize the intrinsic defects in sillenite type crystals: nominally pure Bi12TiO20 (BTO) and doped with vanadium (BTO:V). Optical quality crystals, with the composition Bi12.04±0.08Ti0.76±0.07V0.16±0.02O20, have been grown. Results obtained by these different techniques have shown unambiguously the 5+ valence state of the vanadium ion in BTO:V crystals. In pure BTO samples, the EPR and optical spectra show strong evidence of the presence of the intrinsic defect BiM 3+ + ho + , which consists of a hole h + , mainly located on the oxygen neighbors of the tetrahedrally coordinated Bi 3+ ion. After doping with vanadium, results have shown that the characteristic bands, associated to this hole defect center, disappear, suggesting its transformation in single Bi 3+. Anisotropy of the EPR spectra , at 20 K, is related to Fe 3+ impurities.
In this paper, electron paramagnetic resonance, photoluminescence ͑PL͒ emission, and quantum mech... more In this paper, electron paramagnetic resonance, photoluminescence ͑PL͒ emission, and quantum mechanical calculations were used to observe and understand the structural order-disorder of CaTiO 3 , paying special attention to the role of oxygen vacancy. The PL phenomenon at room temperature of CaTiO 3 is directly influenced by the presence of oxygen vacancies that yield structural order-disorder. These oxygen vacancies bonded at Ti and/or Ca induce new electronic states inside the band gap. Ordered and disordered CaTiO 3 was obtained by the polymeric precursor method.
These experiments assessed the hemodynamic and aquaretic effects of an arginine vasopressin (AVP)... more These experiments assessed the hemodynamic and aquaretic effects of an arginine vasopressin (AVP) antagonist with dual V1V2-receptor inhibiting properties in rats with congestive heart failure resulting from ischemic cardiomyopathy. The compound d(CH2)5-D-Tyr(Et)VAVP was used in these studies. Rats with limited or extensive myocardial infarcts (i.e., with less than 50% or greater than 66% necrosis of the left ventricular wall, respectively, induced by left coronary ligation) and sham-operated controls received the AVP antagonist (100 micrograms/kg i.v.) 4 weeks later. This agent produced an 18% increase in cardiac output (p less than 0.05) and 13% decrease in systemic vascular resistance in the severely damaged rats, both changes being significantly different from those seen in the normal controls or the rats with limited infarcts. All animals exhibited increases in urinary output of 4-10-fold over baseline. We conclude that the hemodynamic and renal effects of this agent are benefi...
Crystalline and quasi-amorphous PZT and PZT:X (X = Ca, Sr and Ba) powders were obtained by the po... more Crystalline and quasi-amorphous PZT and PZT:X (X = Ca, Sr and Ba) powders were obtained by the polymeric precursor method. Electron paramagnetic resonance (EPR) and photoluminescence (PL) data suggest that the presence of order-disorder within the lattice network, i.e., the appearance of symmetrybreaking processes that give rise to non-ideal octahedra and networks of dodecahedral clusters, is an essential factor for the occurrence of PL. Measurements of PL indicate that the shallow defects in the band gap enhance blue light emission.
Background: The activity of the renin-angiotensin-aldosterone system (RAAS) is directly related t... more Background: The activity of the renin-angiotensin-aldosterone system (RAAS) is directly related to overweight and sedentary lifestyles, both of which are associated with hypertension. Aerobic exercise helps control blood pressure (BP) by acting on mechanisms of blood pressure regulation, such as plasma renin activity (PRA). Objective: To assess the effect of aerobic exercise on plasma renin activity in overweight hypertensive patients. Methods: Blood pressure, serum biochemistry and anthropometric parameters of twenty subjects were measured before and after a 16-week exercise training program, three days a week, at 60-80% of maximal heart rate. Data were expressed as mean ± standard deviation or median and interquartile range and analyzed using the student's t-test, Mann-Whitney test, and ANOVA (p < 0.05). Results: Mean age of the study population was 57 ± 7.0, and mean body mass index was 30 ± 3.5 kg/m 2. The aerobic training decreased body fat (35 ± 7.8 to 30 ± 5.6 %), heart rate (HR) (80 ± 10.4 to 77 ± 8.5 bpm), and pulse pressure (PP) (50 ± 11.8 to 46 ± 10.0 mmHg) (p < 0.05), but not plasma renin activity, which ranged from 0.8 (0.45-2.0) to 1.45 (0.8-2.15) ηg/ml/h (p = 0.055). The group that achieved a reduction in waist circumference (WC) (n = 8) experienced also a reduction in systolic BP and PP (p < 0.05). In the group without reduction in WC, none of the BP variables changed. Plasma renin activity (PRA) was not associated with any variable studied. Aerobic training was associated with a decrease in PP in the study group as a whole and with a decrease in systolic BP in the subgroup who experienced a decrease in waist circumference. Conclusion: The aerobic exercise training failed to reduce plasma renin activity in overweight hypertensive patients.
Em sintonia com a tendência científica mundial e a orientação da Associação Médica Brasileira, as... more Em sintonia com a tendência científica mundial e a orientação da Associação Médica Brasileira, as IV Diretrizes Brasileiras de Hipertensão fundamentam suas orientações segundo Graus de Recomendação baseados em níveis de evidência dos estudos clínicos de referência: Grau A-grandes ensaios clínicos aleatorizados e metanálises. Grau B-estudos clínicos e observacionais bem desenhados. Grau C-relatos e séries de casos. Grau D-publicações baseadas em consensos e opiniões de especialistas.
vacancies were identified in disordered SrTiO 3 powders prepared by the polymeric precursor metho... more vacancies were identified in disordered SrTiO 3 powders prepared by the polymeric precursor method, based on experimental measurements by x-ray absorption near edge structure spectroscopy. The paramagnetic complex states of ͓TiO 5 • V O • ͔ and ͓SrO 11 • V O • ͔ with unpaired electrons were confirmed by electron paramagnetic resonance spectroscopy. The disordered powders showed strong photoluminescence at room temperature. Structural defects of disordered powders, in terms of band diagram, density of states, and electronic charges, were interpreted using high-level quantum mechanical calculations in the density functional framework. The four periodic models used here were consistent with the experimental data and explained the presence of photoluminescence.
We discuss how positions of critical points of the three-dimensional Bose-Hubbard model can be ac... more We discuss how positions of critical points of the three-dimensional Bose-Hubbard model can be accurately obtained from variance of the on-site atom number operator, which can be experimentally measured. the idea that we explore is that the derivative of the variance, with respect to the parameter driving the transition, has a pronounced maximum close to critical points. We show that Quantum Monte Carlo studies of this maximum lead to precise determination of critical points for the superfluid-Mott insulator transition in systems with mean number of atoms per lattice site equal to one, two, and three. We also extract from such data the correlation-length critical exponent through the finite-size scaling analysis and discuss how the derivative of the variance can be reliably computed from numerical data for the variance. the same conclusions apply to the derivative of the nearest-neighbor correlation function, which can be obtained from routinely measured time-of-flight images.
Estudiamos el transporte electronico a traves de un hilo cuantico (QW), descrito por medio de una... more Estudiamos el transporte electronico a traves de un hilo cuantico (QW), descrito por medio de una cadena tight-binding, con un punto cuantico (QD) inmerso. Obtenemos la conductancia con una fuerte resonancia Fano; la densidad de estados muestra que este comportamiento esta asociado con una renormalizacion del nivel de energia del QD �Ef , debida a una interaccion de muchos cuerpos, entorno al extremo de la banda de conduccion (CB), fuertemente hibridizada con los picos de Van Hove en la densidad de estados de la cadena unidimensional. Obtenemos que esta resonancia Fano es termicamente activada, arriba de la temperatura de Kondo; esto es debido a un proceso de interferencia cuantica entre la CB y un canal termicamente activado, originado por el QD resonante entorno a un extremo de la CB. Nuestros resultados estan en acuerdo cualitativo con un reporte experimental para un T-coupled QD.
In this work we present a generalization of our previous work of the X−boson approach to the peri... more In this work we present a generalization of our previous work of the X−boson approach to the periodic Anderson model (PAM), adequate to study a novel class of intermetallic 4f and 5f orbitals materials: the topological Kondo insulators, whose paradigmatic material is the compound SmB6. For simplicity, we consider a version of the PAM on a 2D square lattice, adequate to describe Ce−based compounds in two dimensions. The starting point of the model is the 4f − Ce ions orbitals, with J = 5/2 multiplet, in the presence of spin-orbit coupling. Our technique works well for all of the parameters of the model and avoids the unwanted phase transitions of the slave boson mean field theory. We present a critical comparison of our results with those of the usual slave boson method, that has been intensively used to describe this class of materials. We also obtain a new valence first order transition which we attribute to the k dependence of the hybridization.
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Papers by roberto franco