Steviol effect, a glycoside of Stevia rebaudiana, on glucose clearances in rats

Stevia rebaudiana, a South American plant normally used as a natural herbal sweetener, has been suggested as exerting beneficial effects on human health, including as an antihypertensive and antihyperglycemic. The present experiment was undertaken to evaluate the renal excretion of steviol, the aglycone of several natural products extracted from the leaves of S. rebaudiana, and to clarify the actual participation of this compound on the renal excretion of glucose in rats, which has been previously suggested as the preferential action of steviol on the Na+-glucose renal tubular transport system. Steviol was obtained by enzymatic hydrolysis of stevioside with pectinase. Thirty normal male Wistar rats weighing 345 g were used. After a control period, steviol was infused iv at three doses (0.5, 1.0 and 3.0 mg.kg-1/h), according to classical clearance techniques. During all the experiments no significant changes in inulin clearance (Cin) and p-aminohipuric acid clearance (C PAH) were observed. Administration of steviol resulted in a statistically significant increase in the fractional sodium excretion (FeNa+), fractional potassium excretion (FeK+), urinary flow as percent of glomerular filtration rate (V/GFR) and glucose clearance (C G) when compared to controls, but these effects were absent with the dose of 0.5 mg.kg-1/h. The steviol clearance (C S) was higher than the Cin and lower than the C PAH at all the doses employed in this study. The data suggest that steviol is secreted by renal tubular epithelium, causing diuresis, natriuresis, kaliuresis and a fall in renal tubular reabsorption of glucose.

Moral e ��tica: uma leitura psicol��gica

Ap��s um s��culo de reflex��es e investiga����es, como era de se esperar, a Psicologia Moral apresenta sinais de esgotamento de seus referenciais te��ricos cl��ssicos. Consequentemente, novas perspectivas se abrem, entre elas a abordagem te��rica que leva o nome de 'personalidade ��tica', cuja tese ��: para compreendermos os comportamentos morais (deveres) dos indiv��duos, precisamos conhecer a perspectiva ��tica (vida boa) adotadas por eles. Entre os invariantes psicol��gicos de realiza����o de uma 'vida boa', est�� a necessidade de 'expans��o de si pr��prio'. Como tal expans��o implica ter 'representa����es de si' de valor positivo, entre elas poder��o estar aquelas relacionadas �� moral. Se estiverem, o sujeito experimentar�� o sentimento de dever, do contr��rio, a motiva����o para a a����o moral ser�� inexistente ou fraca.

Algumas considera����es sobre o uso da empatia em casos e situa����es limite

Este artigo visa contribuir para a constru����o, por meio do conceito axial de empatia, de uma abordagem te��rica e pr��tica que oriente o manejo cl��nico de casos e situa����es limite, refrat��rios ao m��todo psicanal��tico cl��ssico. O exame da no����o de empatia ser�� realizado a partir de tr��s perspectivas: como modalidade de escuta, como forma de comunica����o e como fator terap��utico. Nossa proposta �� a de dar sustenta����o �� ado����o da empatia como ferramenta cl��nica capaz de ampliar o horizonte de interven����o, incluindo possibilidades de a����o que o m��todo interpretativo n��o comporta.

Learning processes and the neural analysis of conditioning

Classical and operant conditioning principles, such as the behavioral discrepancy-derived assumption that reinforcement always selects antecedent stimulus and response relations, have been studied at the neural level, mainly by observing the strengthening of neuronal responses or synaptic connections. A review of the literature on the neural basis of behavior provided extensive scientific data that indicate a synthesis between the two conditioning processes based mainly on stimulus control in learning tasks. The resulting analysis revealed the following aspects. Dopamine acts as a behavioral discrepancy signal in the midbrain pathway of positive reinforcement, leading toward the nucleus accumbens. Dopamine modulates both types of conditioning in the Aplysia mollusk and in mammals. In vivo and in vitro mollusk preparations show convergence of both types of conditioning in the same motor neuron. Frontal cortical neurons are involved in behavioral discrimination in reversal and extinction procedures, and these neurons preferentially deliver glutamate through conditioned stimulus or discriminative stimulus pathways. Discriminative neural responses can reliably precede operant movements and can also be common to stimuli that share complex symbolic relations. The present article discusses convergent and divergent points between conditioning paradigms at the neural level of analysis to advance our knowledge on reinforcement.

Termogravimetria: um novo enfoque para a cl��ssica determina����o de c��lcio em cascas de ovos

The use of thermoanalytical data in sample preparation is described as a tool to catch the students' attention to some details that can simplify both the analysis and the analytical procedure. In this case, the thermal decomposition of eggshells was first investigated by thermogravimetry (TGA). Although the classical procedures suggest long exposure to high temperatures, the TGA data showed that the decomposition of organic matter takes place immediately when the sample is heated up to 800 ��C under air atmosphere. After decomposition, the calcium content was determined by flame atomic emission photometry and compared with the results obtained using classical volumetric titration with EDTA.

Design, construction and evaluation of a simple pressurized solvent extraction system

This work describes the construction and testing of a simple pressurized solvent extraction (PSE) system. A mixture of acetone:water (80:20), 80 ��C and 103.5 bar, was used to extract two herbicides (Diuron and Bromacil) from a sample of polluted soil, followed by identification and quantification by high-performance liquid chromatography coupled with diode array detector (HPLC-DAD). The system was also used to extract soybean oil (70 ��C and 69 bar) using pentane. The extracted oil was weighed and characterized through the fatty acid methyl ester analysis (myristic (< 0.3%), palmitic (16.3%), stearic (2.8%), oleic (24.5%), linoleic (46.3%), linolenic (9.6%), araquidic (0.3%), gadoleic (< 0.3%), and behenic (0.3%) acids) using high-resolution gas chromatography with flame ionization detection (HRGC-FID). PSE results were compared with those obtained using classical procedures: Soxhlet extraction for the soybean oil and solid-liquid extraction followed by solid-phase extraction (SLE-SPE) for the herbicides. The results showed: 21.25 �� 0.36% (m/m) of oil in the soybeans using the PSE system and 21.55 �� 0.65% (m/m) using the soxhlet extraction system; extraction efficiency (recovery) of herbicides Diuron and Bromacil of 88.7 �� 4.5% and 106.6 �� 8.1%, respectively, using the PSE system, and 96.8 �� 1.0% and 94.2 �� 3.9%, respectively, with the SLP-SPE system; limit of detection (LOD) and limit of quantification (LOQ) for Diuron of 0.012 mg kg-1 and 0.040 mg kg-1, respectively; LOD and LOQ for Bromacil of 0.025 mg kg-1 and 0.083 mg kg-1, respectively. The linearity used ranged from 0.04 to 1.50 mg L-1 for Diuron and from 0.08 to 1.50 mg L-1 for Bromacil. In conclusion, using the PSE system, due to high pressure and temperature, it is possible to make efficient, fast extractions with reduced solvent consumption in an inert atmosphere, which prevents sample and analyte decomposition.

Estudo das condi����es reacionais da rea����o de clivagem oxidativa de &#946;-hidr��xi ��teres bic��clicos promovida por tetr��xido de rut��nio

A systematic study of the reaction of &#946;-hydroxy ethers with ruthenium tetraoxide (RuO4), generated in situ from ruthenium trichloride and sodium periodate, is presented, leading to nine-membered ring keto-lactones in moderate yields. Three different solvent systems - AcOEt/MeCN/H2O, MeCN/H2O and DMC/H2O - were studied leading to the desired products in lower yields than those obtained with the classical mixture of CCl4/MeCN/H2O, commonly used in reactions promoted by this oxidant. However, it is noteworthy that these new solvent systems represent greener alternatives to the chlorinated solvents used in the oxidative cleavage of &#946;-hydroxy ethers by RuO4.

Quest��es contempor��neas sobre natureza e cultura: notas sobre a Sa��de Coletiva e a sociologia no Brasil

O presente artigo discute alguns aspectos da rela����o entre biol��gico e social, tomando por objeto o campo da Sa��de Coletiva no Brasil e o campo das Ci��ncias Sociais, mais especificamente a sociologia. Parte-se do pressuposto de que o conceito que norteia o campo da Sa��de Coletiva, o da determina����o social (formulado em meados dos anos 1970 e 1980), foi profundamente marcado por certa leitura do social, impregnada dos marcos te��ricos cl��ssicos das ci��ncias sociais e marcada pelo cen��rio pol��tico-institucional em que os campos - da Sa��de Coletiva e das Ci��ncias Sociais - encontravam-se historicamente. O objetivo �� discutir o esgotamento dessa formula����o te��rica tendo em vista o cen��rio das profundas mudan��as ocorridas nas sociedades contempor��neas em sua etapa industrial tardia, p��s-industrial ou tardo-moderna. Acredita-se que a discuss��o sobre os marcos te��ricos constitutivos do campo da Sa��de Coletiva contribuir�� para um enfrentamento das quest��es de sa��de mais consoante com as mudan��as sociais ocorridas.

Evaluation of a recombinant p24 antigen for the detection of Feline Immunodeficiency Virus-specific antibodies

Feline Immunodeficiency Virus is a worldwide infection and is considered a significant pathogen. The diagnosis of FIV infections is mainly based on commercially available rapid tests that are highly expensive in Brazil, hence it is rarely performed in the country. Furthermore, lentiviruses grow slowly and poorly in tissue cultures, making the production of viral antigen by classic means and thus the establishment of FIV immunodiagnosis impracticable. In order to deal with this, recombinant DNA techniques were adopted to produce the protein p24, a viral capsid antigen. The protein's reactivity evaluation analyzed by Western blot indicated that this recombinant antigen can be a useful tool for the immunodiagnostic of FIV infections.

Trabalho e imigra����o: uma compara����o Brasil-Argentina

O artigo busca discutir um novo padr��o migrat��rio da Bol��via para o Brasil e para a Argentina, especialmente vinculado �� precariza����o do trabalho e �� inser����o desses imigrantes em formas de trabalho prec��rio. Esse padr��o & aparentemente novo em rela����o �� integra����o dos contingentes migrantes ao longo do s��culo XX & vem produzindo consequ��ncias que ainda est��o por ser mapeadas. Uma delas �� a presen��a de um contingente de bolivianos confinado ao setor de costura, trabalhando e vivendo em oficinas clandestinas, com pouca visibilidade p��blica, como face de uma precariza����o mundializada, resultante do assim chamado ���custo chin��s���. Resultante de um balan��o bibliogr��fico e de uma incurs��o explorat��ria na pesquisa de campo tanto em S��o Paulo como em Buenos Aires, o artigo pretende apontar para aspectos espec��ficos do fen��meno, combinando olhares e perspectivas que cruzam as dimens��es migrat��rias, geracionais e de g��nero.

Menopausal status: a possible predictive factor for recurrence in women with cancer of the uterine cervix without pelvic lymph node metastasis

Abstract Objectives to evaluate risk factors for recurrence of carcinoma of the uterine cervix among women who had undergone radical hysterectomy without pelvic lymph node metastasis, while taking into consideration not only the classical histopathological factors but also sociodemographic, clinical and treatment-related factors. Study desin This was an exploratory analysis on 233 women with carcinoma of the uterine cervix (stages IB and IIA) who were treated by means of radical hysterectomy and pelvic lymphadenectomy, with free surgical margins and without lymph node metastases on conventional histopathological examination. Women with histologically normal lymph nodes but with micrometastases in the immunohistochemical analysis (AE1/AE3) were excluded. Disease-free survival for sociodemographic, clinical and histopathological variables was calculated using the Kaplan-Meier method. The Cox proportional hazards model was used to identify the independent risk factors for recurrence. Twenty-seven recurrences were recorded (11.6%), of which 18 were pelvic, four were distant, four were pelvic + distant and one was of unknown location. The five-year disease-free survival rate among the study population was 88.4%. The independent risk factors for recurrence in the multivariate analysis were: postmenopausal status (HR 14.1; 95% CI: 3.7-53.6; P < 0.001), absence of or slight inflammatory reaction (HR 7.9; 95% CI: 1.7-36.5; P = 0.008) and invasion of the deepest third of the cervix (HR 6.1; 95% CI: 1.3-29.1; P = 0.021). Postoperative radiotherapy was identified as a protective factor against recurrence (HR 0.02; 95% CI: 0.001-0.25; P = 0.003). (To continue) Postmenopausal status is a possible independent risk factor for recurrence even when adjusted for classical prognostic factors (such as tumour size, depth of tumour invasion, capillary embolisation) and treatment-related factors (period of treatment and postoperative radiotherapy status)

Do synergies improve accuracy? A study of speed-accuracy trade-offs during finger force production

We explored possible effects of negative covariation among finger forces in multifinger accurate force production tasks on the classical Fitts's speed-accuracy trade-off. Healthy subjects performed cyclic force changes between pairs of targets ""as quickly and accurately as possible."" Tasks with two force amplitudes and six ratics of force amplitude to target size were performed by each of the four fingers of the right hand and four finger combinations. There was a close to linear relation between movement time and the log-transformed ratio of target amplitude to target size across all finger combinations. There was a close to linear relation between standard deviation of force amplitude and movement time. There were no differences between the performance of either of the two ""radial"" fingers (index and middle) and the multifinger tasks. The ""ulnar"" fingers (little and ring) showed higher indices of variability and longer movement times as compared with both ""radial"" fingers and multifinger combinations. We conclude that potential effects of the negative covariation and also of the task-sharing across a set of fingers are counterbalanced by an increase in individual finger force variability in multifinger tasks as compared with single-finger tasks. The results speak in favor of a feed-forward model of multifinger synergies. They corroborate a hypothesis that multifinger synergies are created not to improve overall accuracy, but to allow the system larger flexibility, for example to deal with unexpected perturbations and concomitant tasks.

Two dimensional analysis of inflatable structures by the positional FEM

This paper presents a, simple two dimensional frame formulation to deal with structures undergoing large motions due to dynamic actions including very thin inflatable structures, balloons. The proposed methodology is based on the minimum potential energy theorem written regarding nodal positions. Velocity, acceleration and strain are achieved directly from positions, not. displacements, characterizing the novelty of the proposed technique. A non-dimensional space is created and the deformation function (change of configuration) is written following two independent mappings from which the strain energy function is written. The classical New-mark equations are used to integrate time. Dumping and non-conservative forces are introduced into the mechanical system by a rheonomic energy function. The final formulation has the advantage of being simple and easy to teach, when compared to classical Counterparts. The behavior of a bench-mark problem (spin-up maneuver) is solved to prove the formulation regarding high circumferential speed applications. Other examples are dedicated to inflatable and very thin structures, in order to test the formulation for further analysis of three dimensional balloons.

An Extension of the Invariance Principle for a Class of Differential Equations with Finite Delay

An extension of the uniform invariance principle for ordinary differential equations with finite delay is developed. The uniform invariance principle allows the derivative of the auxiliary scalar function V to be positive in some bounded sets of the state space while the classical invariance principle assumes that. V <= 0. As a consequence, the uniform invariance principle can deal with a larger class of problems. The main difficulty to prove an invariance principle for functional differential equations is the fact that flows are defined on an infinite dimensional space and, in such spaces, bounded solutions may not be precompact. This difficulty is overcome by imposing the vector field taking bounded sets into bounded sets.

A new constitutive theory extending Hypoplasticity

The purpose of the present theory is to improve Hypoplasticity, especially in relation to reloading processes. This is done by means of two hypoplastic equations (a classical equation along with a new one containing a so-called mnemonic tensor), a cone in stress space and a criterion defining loading, unloading and reloading. (C) 2010 Elsevier Ltd. All rights reserved.