5,893 research outputs found

    Potential application of Saccharomyces cerevisiae strains for the fermentation of banana pulp

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    This paper aimed at evaluating the fermentation behavior of selected Saccharomyces cerevisiae strains in banana pulp and they were compared with commercial yeast (baker’s yeast) for subsequent production of distilled spirits. Five types of microorganisms were used: Four yeast strains obtained from accredited microbiology laboratories were isolated from domestic cachaça distilleries (UNICAMPV1, UFMG-A905, UFMG-A1007 and UFMG-A1240) and commercial pressed yeast (COMMERCIAL-yeast). The fermentation parameters of the studied S. cerevisiae strains were significantly different. COMMERCIAL-yeast and UNICAMP-V1 strain presented higher ethanol yield and better yeast efficiency in converting total reducing sugars (TRS) into alcohol, with ethanol yields of 83.07 and 94.06%, and yeast efficiency of 90.75 and 96.41%, respectively for UNICAMP V1 and COMMERCIAL-yeast. The higher alcohol contents of 82.26 and 78.05 mg/100 ml anhydrous alcohol were obtained by the UNICAMP-V1 and COMMERCIAL-yeast, respectively. No significant differences in fermentative parameters were observed between COMMERCIAL-yeast and UNICAMP-V1 strain. The UFMG-A1240 strain showed the lowest ethanol yield and therefore not suitable for the production of distilled spirits made of bananas, despite being useful for the production of cachaça. Methanol contents did not significantly vary among the five strains tested, except for UFMG-A1007, which produced significantly higher quantities of 0.19 ml/100 ml anhydrous alcohol. However, higher alcohols contents varied significantly between the five strains tests, with the UFMG-A1007 and UFMG-A1240 strains producing the lowest quantities of higher alcohols (30.04 and 48.69 mg/100 ml anhydrous alcohol, respectively). In conclusion, the S. cerevisiae strains UNICAMP-V1 and the COMMERCIAL-yeast showed better fermentation behavior, did not produce high methanol and higher alcohols amounts, and therefore were recommended for the production of distilled spirits made of banana in pilot-scale plants.Key words: Yeast, Saccharomyces cerevisiae, alcoholic fermentation, banana spirits

    The dynamics of apparent horizons in Robinson-Trautman spacetimes

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    We present an alternative scheme of finding apparent horizons based on spectral methods applied to Robinson-Trautman spacetimes. We have considered distinct initial data such as representing the spheroids of matter and the head-on collision of two non-rotating black holes. The evolution of the apparent horizon is presented. We have obtained in some cases a mass gap between the final Bondi and apparent horizon masses, whose implications were briefly commented in the light of the thermodynamics of black holes.Comment: 9 pages, 7 figure

    Pseudoboehmite as a drug delivery system for acyclovir

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    Herpes simplex virus is among the most prevalent sexually transmitted infections. Acyclovir is a potent, selective inhibitor of herpes viruses and it is indicated for the treatment and management of recurrent cold sores on the lips and face, genital herpes, among other diseases. The problem of the oral bioavailability of acyclovir is limited because of the low permeability across the gastrointestinal membrane. The use of nanoparticles of pseudoboehmite as a drug delivery system in vitro assays is a promising approach to further the permeability of acyclovir release. Here we report the synthesis of high purity pseudoboehmite from aluminium nitrate and ammonium hydroxide containing nanoparticles, using the sol–gel method, as a drug delivery system to improve the systemic bioavailability of acyclovir. The presence of pseudoboehmite nanoparticles were verified by infrared spectroscopy, transmission electron microscopy, and X-ray diffraction techniques. In vivo tests were performed with Wistar rats to compare the release of acyclovir, with and without the addition of pseudoboehmite. The administration of acyclovir with the addition of pseudoboehmite increased the drug content by 4.6 times in the plasma of Wistar rats after 4 h administration. We determined that the toxicity of pseudoboehmite is low up to 10 mg/mL, in gel and the dried pseudoboehmite nanoparticles.The authors thank the Mackenzie Presbyterian University, Texas Tech University, Mack Pesquisa, Coordenação de Aperfeiçoamento de Pessoal de Nível Superior—Brasil (CAPES), Cnpq, and FAPESP (grant 2010/19157-9 and grant 2017/22396-4) for the sponsorship to this project

    Computational Complexity of interacting electrons and fundamental limitations of Density Functional Theory

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    One of the central problems in quantum mechanics is to determine the ground state properties of a system of electrons interacting via the Coulomb potential. Since its introduction by Hohenberg, Kohn, and Sham, Density Functional Theory (DFT) has become the most widely used and successful method for simulating systems of interacting electrons, making their original work one of the most cited in physics. In this letter, we show that the field of computational complexity imposes fundamental limitations on DFT, as an efficient description of the associated universal functional would allow to solve any problem in the class QMA (the quantum version of NP) and thus particularly any problem in NP in polynomial time. This follows from the fact that finding the ground state energy of the Hubbard model in an external magnetic field is a hard problem even for a quantum computer, while given the universal functional it can be computed efficiently using DFT. This provides a clear illustration how the field of quantum computing is useful even if quantum computers would never be built.Comment: 8 pages, 3 figures. v2: Version accepted at Nature Physics; differs significantly from v1 (including new title). Includes an extra appendix (not contained in the journal version) on the NP-completeness of Hartree-Fock, which is taken from v

    El recien nacido con dolor: el papel del equipo de enfermeria

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    It's a quantitative, descriptive and cross study conducted with the nurse team working in the field of neonatology at the three hospitals, Alfenas-MG. Aimed to describe the forms of pain assessment of the newborn used by nurse team and analyze the practice of nursing as pain management of neonates. Data were collected through a semi-structured formulary, from August to September 2008, of 42 nurses working. The analyze was performed using SPSS software using descriptive statistics and correlation test. It was observed that the respondents recognize that the newborn is capable of feeling pain and evaluated by physiological and behavioral changes and that there isn't pain assessment scales standardized in the institutions. For the management, carry out pharmacological and nonpharmacological interventions. There is need to train professionals contributing to the assessment and management of pain, promoting of holistic care of the neonate.Estudio cuantitativo, descriptivo y transversal realizado con profesionales de Enfermería que actúan en el área de Neonatología en los tres hospitales de Alfenas, Minas Gerais. Se objetivó describir las formas de evaluación del dolor del recién nacido utilizados por el personal de enfermería y analizar la práctica de la enfermería como el manejo del dolor del neonato. La recolección de datos fue hecha por medio de un formulario semiestructurado, entre agosto y septiembre de 2008, con 42 profesionales. El análisis fue hecho con el software SPSS, utilizando la estadística descriptiva y la prueba de correlación. Los entrevistados reconocen que el neonato es capaz de sentir dolor y esto se evalúa a través de alteraciones fisiológicas y de comportamiento, no hay utilización de escalas de evaluación del dolor estandarizadas en las instituciones. Para el manejo, realizan intervenciones farmacológicas y no farmacológicas. Hay necesidad de capacitar profesionales contribuyendo para la evaluación y manejo del dolor, para la promoción del cuidado integral al neonato.Estudo quantitativo, descritivo e transversal realizado com profissionais de enfermagem que atuam em neonatologia nos três hospitais de Alfenas-MG. Objetivou descrever as formas de avaliação de dor do recém-nascido utilizadas pela equipe de enfermagem e analisar a prática da enfermagem quanto ao manejo da dor do neonato. A coleta de dados foi feita por meio de formulário semiestruturado, de agosto a setembro de 2008, com 42 profissionais. A análise foi feita pelo software SPSS utilizando estatística descritiva e teste de correlação. Os entrevistados acreditam que o recém-nascido é capaz de sentir dor e a avaliam por meio de alterações fisiológicas e comportamentais, e que não há utilização de escalas de avaliação álgica padronizadas nas instituições. Para o manejo, realizam intervenções farmacológicas e não farmacológicas. Há necessidade de capacitar os profissionais, contribuindo para a avaliação e o manejo da dor, e promovendo o cuidado integral ao neonato.Universidade de São Paulo Escola de Enfermagem de Ribeirao Preto Departamento de Enfermagem Materno-infantil e Saude PublicaUniversidade Federal de São Paulo (UNIFESP) Departamento de Enfermagem Pediatrica Escola Paulista de EnfermagemUniversidade Federal de Alfenas Escola de Enfermagem Programa de Pos-graduacao em EnfermagemUniversidade de São Paulo Escola de Enfermagem de Ribeirao Preto Departamento de Enfermagem Geral e EspecializadaUniversidade Federal de Alfenas Escola de EnfermagemPrograma de Pos-graduacao em Enfermagem Programa de Pos-graduacao em EnfermagemEscola de Enfermagem Escola de EnfermagemUniversidade de São PauloUNIFESP, Depto. de Enfermagem Pediatrica Escola Paulista de Enfermagem (EPE)SciEL

    Simulations of extensional flow in microrheometric devices

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    We present a detailed numerical study of the flow of a Newtonian fluid through microrheometric devices featuring a sudden contraction–expansion. This flow configuration is typically used to generate extensional deformations and high strain rates. The excess pressure drop resulting from the converging and diverging flow is an important dynamic measure to quantify if the device is intended to be used as a microfluidic extensional rheometer. To explore this idea, we examine the effect of the contraction length, aspect ratio and Reynolds number on the flow kinematics and resulting pressure field. Analysis of the computed velocity and pressure fields show that, for typical experimental conditions used in microfluidic devices, the steady flow is highly three-dimensional with open spiraling vortical structures in the stagnant corner regions. The numerical simulations of the local kinematics and global pressure drop are in good agreement with experimental results. The device aspect ratio is shown to have a strong impact on the flow and consequently on the excess pressure drop, which is quantified in terms of the dimensionless Couette and Bagley correction factors. We suggest an approach for calculating the Bagley correction which may be especially appropriate for planar microchannels

    Tidal Forces in Reissner-Nordström Spacetimes

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    We analyze the tidal forces produced in the spacetime of Reissner-Nordstr\"om black holes. We point out that the radial component of the tidal force changes sign just outside the event horizon if the charge-to-mass ratio is close to 11 unlike in Schwarzschild spacetime of uncharged black holes, and that the angular component changes sign between the outer and inner horizons. We solve the geodesic deviation equations for radially falling bodies towards the charged black hole. We find, for example, that the radial component of the geodesic deviation vector starts decreasing inside the event horizon unlike in the Schwarzschild case

    Studies of Copaifera luetzelburgii Harms in reproductive pharmacology: In vivo and in vitro approaches

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    The objective of this study was to evaluate the estrogenic and anti-estrogenic actions, as well as the reproductive and foetal toxicity, of the ethanol extract from Copaifera luetzelburgii (EEtOH-Cl). In the experiment of (anti) estrogenicity, nulliparous Wistar rats were treated for 3 days with EEtOH-Cl (125, 250 and 500 mg/kg); estradiol (E, 5 μg/kg); E + EEtOH-Cl; tamoxifen (T, 4mg/kg). This extract presented estrogenic activity by increasing the relative weight (%) of the uterus of rats treated at doses of 125, 250 and 500 mg/kg (0.267 ± 0.016*, 0.231 ± 0.014*, 0.242 ± 0.015*), and it showed anti-estrogenic activity when associated with estradiol (0.116 ± 0.006*, 0.103 ± 0.06*, 0.098 ± 0.05*), respectively. For assessment of toxicity in pregnancy, the animals were divided into two groups and treated daily with EEtOH-Cl. In the first group, the effect of the extract on the development of pregnancy from first to seventh day was observed, and in the second group, from 8 to 21 days, there was no change of these parameters or the viability of the progeny when the study assessed reproductive and foetal toxicity; however, there was shortening of pregnancy (125 mg/kg) without affecting the progeny. In the in vitro study, uterine strips of pregnant (P) and non-pregnant (NP) females were used. In both groups, half received EEtOH-Cl (vo) for 13 days (treated females - T), and the other half received EEtOH-Cl directly to the isolated organ bath system (untreated - NT). In vitro study on the uterus of pregnant animals pretreated with doses of 250 and 500 mg/kg showed that there was inhibition of KCl 80-induced phasic contractions (0.490 ± 0.110, 0.540 ± 0.092), respectively. Also, the contractions induced by oxytocin were inhibited at a dose of 500 mg/kg (0.380 ± 0.109). In non-pregnant, non-treated females, the extract at a concentration of 125 μg/mL (0.180 ± 0.062) also inhibited the contractions induced by oxytocin. Thus, EEtOH-Cl demonstrated estrogenic activity, but when combined with estradiol, it demonstrated anti-estrogenic activity. It did not induce toxicity in the progenitors or in the progeny, and it inhibited isometric contractions induced by oxytocin and KCl 80 mM in pregnant and non-pregnant rats.Keywords: Copaifera luetzelburgii, (anti-)estrogenicity, reproductive toxicity, phasic contractionsAfrican Journal of Biotechnology Vol. 12(24), pp. 3864-387
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