1,924 research outputs found

    Development and Evaluation of Praziquantel Solid Dispersions in Sodium Starch Glycolate

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    Purpose: To develop and characterize solid dispersions of praziquantel (PZQ) with sodium starch glycolate (SSG) for enhanced drug solubility.Methods: PZQ solid dispersion (SD) was prepared using co-precipitation method by solvent evaporation. The ratios of PZQ to SSG were 2:1, 1:1, 1:2, 1:3 (w/w). PZQ solubility was evaluated in purified water, and PZQ dissolution test was carried out in 0.1N HCl. Structural characterization of the dispersions was accomplished by x-ray diffraction (XRD) and infrared spe ctroscopy (FTIR) while the external morphology of the SDs, SSG and PZQ were studied by scanning electron microscopy (SEM). Mucoadhesion properties of the SD (1:3) and SSG, on mucin disks were examined using texture profile analysis.Results: The highest solubility was obtained with 1:3 solid dispersion, with PZQ solubility of 97.31 %, which is 3.65-fold greater than the solubility of pure PZQ and physical misture (PM, 1:3). XRD results indicate a reduction in PZQ crystallinity while infrared spectra showed that the functional groups of PZQ and SSG were preserved. SEM showed that the physical structure of PZQ was modified from crystalline to amorphous. The amount of PZQ in PM and SD (1:3) that dissolved in 60 min was 70 and 88 %, respectively, and these values increased to 76 and 96 %, respectively. The solid dispersion reduced the mucoadhesive property of the glycolate.Conclusion: Solid dispersion formulation using SSG is a good alternative approach for increasing the dissolution rate of PZQ.Keywords: Praziquantel, Drug bioavailability, Schistosomiasis, Solid dispersion, Co-precipitation, Sodium starch glycolat

    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

    Advertisement call of Scinax littoralis and S. angrensis (Amphibia: Anura: Hylidae), with notes on the reproductive activity of S. littoralis

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    Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Scinax littoralis and S. angrensis are poorly known Atlantic forest endemic species from the Scinax catharinae group, which is known from southern and southeastern Brazil. Herein, we describe the advertisement calls of these two species and compare them to other species within the S. catharinae group. Additionally, we provide information on breeding sites, and calling activity in S. littoralis. Advertisement calls of S. angrensis and S. littoralis are composed of multi-pulsed notes with multiple frequency bands and frequency modulation. Scinax littoralis has a higher minimum and maximum frequency, and lower dominant frequency than S. angrensis, while Scinax littoralis has a longer call. Scinax littoralis appears to be a habitat generalist, occurring from secondary to mature forests, and breeding both in temporary and in permanent ponds. Male S. littoralis were usually observed calling perched on shrub stems, and displayed satellite behavior when the male density was high.72297308Fundacao Grupo O Boticario de Protecao a Natureza [FBPN-UFPR 623]Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundacao Grupo O Boticario de Protecao a Natureza [FBPN-UFPR 623]FAPESP [2008/50575-1, UNESP/PROPe (edital 05/2012)

    Perspectives on the Trypanosoma cruzi-host cell receptor interaction

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    Chagas disease is caused by the parasite Trypanosoma cruzi. The critical initial event is the interaction of the trypomastigote form of the parasite with host receptors. This review highlights recent observations concerning these interactions. Some of the key receptors considered are those for thromboxane, bradykinin, and for the nerve growth factor TrKA. Other important receptors such as galectin-3, thrombospondin, and laminin are also discussed. Investigation into the molecular biology and cell biology of host receptors for T. cruzi may provide novel therapeutic targets

    TEORIAS DE ENFERMAGEM: IMPORTÂNCIA DA CORRETA APLICAÇÃO DOS CONCEITOS

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    Theoretical-reflexive research, whose aim is to analyze the clarity of concept stimulus in the Roy Model, for best comprehension in nursing practice. It was developed in three phases: 1- Search of studies that utilized the Roy Model; 2- Conducted reading for comprehension of the concept stimulus and 3- Analysis of clarity of the concept. The three studies were conducted at master level. The analysis of the studies shows deficiency in the clarity of the concept stimulus, being predominant the ambiguity in the classification and differentiation of the focal and contextual stimuli, without the existence of consistency and uniformity. The need arises to deepen the theories of nursing for adequate application in the areas of research: nursing education and practice, optimizing and improving its use, as well as, enabling the comprehension of determined concepts that are not sufficiently clear. The worries that arise among the nurses will provide a more profound approach to the study, enabling the advance of theories, as well as new findings, leading to necessary changes.  Investigación teórico-reflexiva cuyo objetivo fue analizar la claridad del concepto estímulo según el  modelo de Roy, para mayor comprensión en la práctica de enfermería. Desarrollada en tres etapas: 1ª- Levantamiento de estudios que utilizaron el Modelo de Roy; 2ª - Lectura dirigida hacia la comprensión del concepto estímulo y 3ª - Análisis de la claridad del concepto. Fueron utilizados tres estudios, a  nivel de maestrado. El análisis de los estudios demuestra deficiencia en la claridad del concepto estímulo, predominando ambigüedad en la clasificación y diferenciación de los estímulos focales y contextuales, sin consistencia y uniformidad. Se evidencia la necesidad de profundizar en las teorías de enfermería, para su aplicación adecuada en las áreas de investigación, enseñanza y práctica, optimizando y mejorando su uso, además de posibilitar la comprensión de determinados conceptos no suficientemente claros. Las inquietudes surgidas entre los enfermeros podrán motivar un abordaje más profundo de los estudios, posibilitando el avance de las teorías, así  como nuevos descubrimientos, dirigiendo los cambios necesariosPesquisa teórico-reflexiva, objetivando analisar a clareza do conceito estímulo no modelo de Roy, para maior compreensão na prática de enfermagem. Desenvolvido em três etapas: 1ª- Levantamento de estudos que utilizaram o Modelo de Roy; 2ª - Leitura dirigida para a compreensão do conceito estímulo e 3ª - Análise da clareza do conceito. Foram utilizados três estudos, em nível de mestrado. A análise dos estudos demonstra deficiência na clareza do conceito estímulo, predominando ambigüidade na classificação e diferenciação dos estímulos focais e contextuais, não existindo consistência e uniformidade. Evidencia-se a necessidade do aprofundamento nas teorias de enfermagem, para a aplicação adequada nas áreas de pesquisa, ensino e prática, otimizando e aprimorando seu uso, além de possibilitar a compreensão de determinados conceitos, não suficientemente claros. As inquietações surgidas entre os enfermeiros poderão proporcionar o aprofundamento nos estudos, possibilitando o avanço das teorias, assim como novos achados, direcionando as mudanças necessárias

    Crude Heparin Preparations Unveil the Presence of Structurally Diverse Oversulfated Contaminants

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    Nowadays, pharmaceutical heparin is purified from porcine and bovine intestinal mucosa. In the past decade there has been an ongoing concern about the safety of heparin, since in 2008, adverse effects associated with the presence of an oversulfated chondroitin sulfate (OSCS) were observed in preparations of pharmaceutical porcine heparin, which led to the death of patients, causing a global public health crisis. However, it has not been clarified whether OSCS has been added to the purified heparin preparation, or whether it has already been introduced during the production of the raw heparin. Using a combination of different analytical methods, we investigate both crude and final heparin products and we are able to demonstrate that the sulfated contaminants are intentionally introduced in the initial steps of heparin preparation. Furthermore, the results show that the oversulfated compounds are not structurally homogeneous. In addition, we show that these contaminants are able to bind to cells in using well known heparin binding sites. Together, the data highlights the importance of heparin quality control even at the initial stages of its production

    Quantum Acoustics with Surface Acoustic Waves

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    It has recently been demonstrated that surface acoustic waves (SAWs) can interact with superconducting qubits at the quantum level. SAW resonators in the GHz frequency range have also been found to have low loss at temperatures compatible with superconducting quantum circuits. These advances open up new possibilities to use the phonon degree of freedom to carry quantum information. In this paper, we give a description of the basic SAW components needed to develop quantum circuits, where propagating or localized SAW-phonons are used both to study basic physics and to manipulate quantum information. Using phonons instead of photons offers new possibilities which make these quantum acoustic circuits very interesting. We discuss general considerations for SAW experiments at the quantum level and describe experiments both with SAW resonators and with interaction between SAWs and a qubit. We also discuss several potential future developments.Comment: 14 pages, 12 figure

    Widespread forest vertebrate extinctions induced by a mega hydroelectric dam in lowland Amazonia

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    Mega hydropower projects in tropical forests pose a major emergent threat to terrestrial and freshwater biodiversity worldwide. Despite the unprecedented number of existing, underconstruction and planned hydroelectric dams in lowland tropical forests, long-term effects on biodiversity have yet to be evaluated. We examine how medium and large-bodied assemblages of terrestrial and arboreal vertebrates (including 35 mammal, bird and tortoise species) responded to the drastic 26-year post-isolation history of archipelagic alteration in landscape structure and habitat quality in a major hydroelectric reservoir of Central Amazonia. The Balbina Hydroelectric Dam inundated 3,129 km2 of primary forests, simultaneously isolating 3,546 land-bridge islands. We conducted intensive biodiversity surveys at 37 of those islands and three adjacent continuous forests using a combination of four survey techniques, and detected strong forest habitat area effects in explaining patterns of vertebrate extinction. Beyond clear area effects, edge-mediated surface fire disturbance was the most important additional driver of species loss, particularly in islands smaller than 10 ha. Based on species-area models, we predict that only 0.7% of all islands now harbor a species-rich vertebrate assemblage consisting of ≥80% of all species. We highlight the colossal erosion in vertebrate diversity driven by a man-made dam and show that the biodiversity impacts of mega dams in lowland tropical forest regions have been severely overlooked. The geopolitical strategy to deploy many more large hydropower infrastructure projects in regions like lowland Amazonia should be urgently reassessed, and we strongly advise that long-term biodiversity impacts should be explicitly included in pre-approval environmental impact assessments
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