Publications by authors named "Sergio Santos"

A method to monitor variations in the conservative and dissipative forces in dynamic atomic force microscopy is proposed in order to investigate the effects of exposing a surface to different sets of environmental conditions for prolonged periods of time. The variations are quantified by proposing and defining two metrics, one for conservative and another for dissipative interactions. Mica and graphite are chosen as model samples because they are atomically flat and easy to cleave.

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Corrole macrocycles are very appealing dyes for incorporation into light harvesting devices. This work shows the sensorial ability of 5,10,15-tris(pentafluorophenyl)corrole 1 and its monoanionic species toward Na(+), Ca(2+), Cu(2+), Cd(2+), Pb(2+), Hg(2+), Ag(+), and Al(3+) metal ions in toluene and acetonitrile. The photophysical studies toward metal ions were carried out by absorption and emission spectroscopy.

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The scope of this study was to evaluate the effects of a public program of application of botulinum toxin type A (BoNT-A) in terms of muscle spasticity, range of motion, quality of gait, functional independence and quality of life of children and adolescents with cerebral palsy (CP). A quasi-experimental study was conducted with 14 children with CP to evaluate the effects of three applications of BoNT-A, at intervals of three months. Children were assessed using the Modified Ashworth Rating Scale, the Manual Goniometer, the Physician Rating Scale, the Pediatric Evaluation of Disability Inventory (PEDI) and the Caregiver Questionnaire (CQ).

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A method to synthesize meso-tetraphenylbenzoporphyrin-2(2),2(3)-dicarboxylic anhydride is reported. This compound reacts with alkylamines and arylamines to afford the corresponding "phthalimides" in moderate to excellent yields. The reaction of the title compound with benzene-1,4-diamine or with benzene-1,3-diamine yields the corresponding N,N'-(phenylene)bisphthalimides, whereas with benzene-1,2-diamine or naphthalene-1,8-diamine it affords heterocyclic-fused porphyrins.

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Angiotensin (Ang)-(1-7) has been described as an important tool on treating and preventing metabolic disorders. In this study, we aimed to evaluate the effect of an oral formulation of Ang-(1-7) included in hydroxypropylβ-cyclodextrin (HPβCD/Ang-[1-7]) on hepatic function, steatosis, and on liver inflammatory markers expression in mice treated with a high-fat diet. Male FVB/N mice were divided into 4 groups and fed for 60 days, with each group receiving 1 of the following diets: standard diet+HPβCD, standard diet+Ang-(1-7)/HPβCD, high-fat diet+HPβCD, or high-fat diet+Ang-[1-7]/HPβCD.

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Obesity is characterized by a pro-inflammatory state commonly associated with type 2 diabetes and fat-liver disease. In the last few years, different studies pointed out the role of Angiotensin (Ang)-(1-7) in the metabolic regulation. The aim of the present study was to evaluate the effect of oral-administration of Ang-(1-7) in metabolism and inflammatory state of high-fat feed rats.

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Sirtuins (SIRTs) are a family of regulatory proteins of genetic information with a high degree of conservation among species. The SIRTs are heavily involved in several physiological functions including control of gene expression, metabolism, and aging. SIRT1 has been the most studied sirtuin and plays important role in the prevention and progression of neurodegenerative diseases acting in different pathways of proteins involved in brain function.

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Rationale: Glycophthalocyanines have a great promising potential in many scientific areas. However, their structural characterization is not an easy task. To overcome this drawback, it is urgent to develop simple and efficient methodologies to characterize this type of compounds.

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The β-adrenergic blockers and antagonists of the renin-angiotensin system (RAS) are among the drugs that present better results in the control of cardio-metabolic diseases. The aim of the present study was to evaluate the effect of the association of the β-blocker, atenolol, and an oral formulation of Ang-(1-7) on lipid metabolism in spontaneously hypertensive rats (SHR). The main results showed that SHR treated with oral formulation of Ang-(1-7) in combination to atenolol have an improvement of lipid metabolism with a reduction of total plasma cholesterol, improvement of oral fat load tolerance and an increase in the lipolytic response stimulated by the β-adrenergic agonist, isoproterenol, without modification of resting glucose or insulin sensitivity in adipocytes.

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This study was aimed at understanding, from the nurses' perspective, the experience of going through the Systematization of nursing care (SNC) in an obstetric service unit. We used grounded theory as the theoretical and methodological framework. The subjects of this study consisted of thirteen nurses from a public hospital in the city of João Pessoa, in the state of Paraíba.

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Here, processes through which the energy stored in an atomic force microscope cantilever dissipates in the tip-sample interaction are first decoupled qualitatively. A formalism is then presented and shown to allow quantification of fundamental aspects of nanoscale dissipation such as deformation, viscosity, and surface energy hysteresis. Accurate quantification of energy dissipation requires precise calibration of the conversion of the oscillation amplitude from volts to nanometers.

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The Renin-Angiotensin System (RAS) is recognized as the main biological system involved in cardiovascular and hydroelectrolyte homeostasis. It is well established in literature that RAS blockers retard the progression of renal failure in type 1 [angiotensin converting enzyme (ACE) inhibitors] and in type 2 [angiotensin type 1 receptor (AT1) antagonists] diabetes mellitus and in non-diabetic chronic kidney diseases. More recently, it was shown that newer therapeutic agents, the renin inhibitors, also exert renoprotective actions.

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During their synthesis, multi-walled carbon nanotubes can be aligned and impregnated in a polymer matrix to form an electrically conductive and flexible nanocomposite with high backing density. The material exhibits the highest reported electrical conductivity of CNT-epoxy composites (350 S/m). Here, we show how conductive atomic force microscopy can be used to study the electrical transport mechanism in order to explain the enhanced electrical properties of the composite.

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This chapter reviews amplitude modulation (AM) AFM in air and its applications to high-resolution imaging and interpretation of macromolecular complexes. We discuss single DNA molecular imaging and DNA-protein interactions, such as those with topoisomerases and RNA polymerase. We show how relative humidity can have a major influence on resolution and contrast and how it can also affect conformational switching of supercoiled DNA.

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The renin-angiotensin system (RAS) is involved in the cardiac and vascular remodeling associated with cardiovascular diseases. Angiotensin (Ang) II/AT(1) axis is known to promote cardiac hypertrophy and collagen deposition. In contrast, Ang-(1-7)/Mas axis opposes Ang II effects in the heart producing anti-trophic and anti-fibrotic effects.

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The renin-angiotensin (Ang) system (RAS) plays an important role in the control of glucose metabolism and glycemia. Several studies demonstrated that the effects of angiotensin-(1-7) are mainly opposite to the actions of biological angiotensin II. Recent studies have demonstrated that rats with increased circulating angiotensin-(1-7), acting through the G protein coupled receptor Mas, have enhanced glucose tolerance and insulin sensitivity, presenting improved metabolic parameters.

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Multifrequency atomic force microscopy holds promise as a method to provide qualitative and quantitative information about samples with high spatial resolution. Here, we provide experimental evidence of the excitation of subharmonics in ambient conditions in the regions where capillary interactions are predicted to be the mechanism of excitation. We also experimentally decouple a second mechanism for subharmonic excitation that is highly independent of environmental conditions such as relative humidity.

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Ambient amplitude modulation atomic force microscopy (AM AFM) is one of the most broadly used techniques as it is versatile and can provide measurements of single nanostructures routinely. Nevertheless, the technique typically measures an apparent height of nanostructures that does not coincide with the true height. Here, we carry out an exhaustive study of the several possibilities that arise in the presence and in the absence of adsorbed water layers when measuring the height of nanostructures.

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Introduction: The aim of the present study was to evaluate the effect of a transgenic-induced chronic increase of Ang-(1-7) on the expression of inflammatory markers in adipose tissue and the metabolic profile in rats treated with high-fat diet.

Research Design And Methods: Transgenic rats expressing an Ang-(1-7)-producing fusion protein (TGR L-3292) and Sprague Dawley (SD) control rats 4 weeks old were treated for 8 weeks with a high-fat diet. Food intake and body weight were measured once a week.

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We present a complete set of experimental approaches for the NMR assignment of powdered tripeptide glutathione at natural isotopic abundance, based on J-coupling and dipolar NMR techniques combined with (1)H CRAMPS decoupling. To fully assign the spectra, two-dimensional (2D) high-resolution methods, such as (1)H-(13)C INEPT-HSQC/PRESTO heteronuclear correlations (HETCOR), (1)H-(1)H double-quantum (DQ), and (1)H-(14)N D-HMQC correlation experiments, have been used. To support the interpretation of the experimental data, periodic density functional theory calculations together with the GIPAW approach have been used to calculate the (1)H and (13)C chemical shifts.

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We evaluated the hypothesis that activation of endogenous angiotensin-converting enzyme (ACE) 2 would improve cardiac dysfunction induced by diabetes. Ten days after diabetes induction (streptozotocin, 50 mg/kg, i.v.

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Variations in intradialytic blood pressure (BP) are a common and predictable occurrence in ESRD patients. These are caused by a decrease in blood volume provoked by ultrafiltration, lack of normal compensatory responses to fluid removal, underlying cardiac disease, and electrolyte changes that may adversely affect cardiovascular function. Intradialytic hypotension is the most frequent complication of the hemodialysis (HD) procedure and is fundamentally a consequence of an ultrafiltration rate that surpasses mechanisms activated to avert a decline in BP.

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We provide a method to characterize the tip radius of an atomic force microscopy in situ by monitoring the dynamics of the cantilever in ambient conditions. The key concept is that the value of free amplitude for which transitions from the attractive to repulsive force regimes are observed, strongly depends on the curvature of the tip. In practice, the smaller the value of free amplitude required to observe a transition, the sharper the tip.

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Instantaneous and average energy dissipation distributions in the nanoscale due to short and long range interactions are described. We employ both a purely continuous and a semi-discrete approach to analyze the consequences of this distribution in terms of rate of heat generation, thermal flux, adhesion hysteresis, viscoelasticity and atomic dissipative processes. The effects of peak values are also discussed in terms of the validity of the use of average values of power and energy dissipation.

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This is a qualitative descriptive exploratory study, conducted in Higher Education Institutions (HEI) which offers Nursing course, in Joao Pessoa-PB. The study aimed to understand the concept of managers about the need for organizational changes to attend customers with special needs. Four managers participated in the study.

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