Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 50
Filtrar
Mais filtros

Base de dados
Tipo de documento
Intervalo de ano de publicação
1.
Qual Life Res ; 27(10): 2609-2618, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-29881894

RESUMO

PURPOSE: Health-related quality of life (HRQoL) is a well-known construct that refers to a state of complete physical, mental, and social well-being. Its relationship with multiple forms of violence, including bullying, has been widely explored, but this is not the case for cyberbullying. The main objective is to analyze how HRQoL varies depending on the role played in cyberbullying, its temporal stability, and gender and age differences. METHOD: An analytical and longitudinal study was conducted at two temporal moments. At Time 1 (December 2015), 920 Spanish students aged between 11 and 18 years participated (Mage = 13.36, SD = 1.83: 48.9% boys and 51.1% girls). At Time 2 (April 2016), there were 313 participants (Mage 12.81 years, SD = 1.59: 53.4% boys and 46.6% girls). We used the Cyberbullying Test (technological scale) and the Spanish version of the KIDSCREEN-52. RESULTS: Cybervictims and cyberbully-victims present worse scores in all dimensions of the KIDSCREEN-52 (p < .001), compared to cyberbystanders or uninvolved individuals. There are gender differences only in cyberaggression and cyberbystanding. There are significant inverse correlations between all the dimensions of the KIDSCREEN-52 and cybervictimization, with Bullying (r = - .603, p < .001), Mood (r = - .329, p < .001), and School environment (r = - .327, p < .001) being particularly relevant. There were statistically significant differences between T1 and T2 for cyberbystanding (lower scores at T2). CONCLUSION: Cybervictims and cyberbully-victims have worse quality of life in all the dimensions than uninvolved individuals, especially in Psychological well-being, School environment, and Bullying.


Assuntos
Vítimas de Crime/psicologia , Cyberbullying/psicologia , Qualidade de Vida/psicologia , Adolescente , Comportamento do Adolescente/psicologia , Criança , Feminino , Humanos , Internet , Estudos Longitudinais , Masculino , Psicometria/métodos , Estudantes/psicologia , Inquéritos e Questionários
2.
Bioorg Chem ; 73: 37-42, 2017 08.
Artigo em Inglês | MEDLINE | ID: mdl-28599132

RESUMO

Quorum sensing (QS) is a cell-to-cell signaling communication system that controls the virulence behavior of a broad spectrum of bacterial pathogens, participating also in the development of biofilms, responsible of the antibiotic ineffectiveness in many infections. Therefore, QS system is an attractive target for antimicrobial therapy. In this study, we compare the effect of seven structurally related coumarins against bacterial growth, biofilm formation and elastase activity of Pseudomonas aeruginosa. In addition, the anti-pathogenic capacity of the seven coumarins was evaluated on the wild type and the biosensor strain of Chromobacterium violaceum. The comparative study of coumarins showed that molecules with hydroxyl groups on the aromatic ring displayed higher activity on the inhibition of biofilm formation of P. aeruginosa over coumarins with substituents in positions 3 and 4 or without the double 3,4-bond. These 3 or 4-hydroxylated positions caused a decrease in the anti-biofilm activity obtained for coumarin. However, the hydroxyl group in position 3 of the pyrone ring was important for the inhibition of C. violaceum QS and elastolytic activity of P. aeruginosa. The effects observed were active independently of any effect on growth. According to our results, coumarin and its hydroxylated derivatives represent an interesting group of compounds to use as anti-virulence agents against the human pathogen P. aeruginosa.


Assuntos
Antibacterianos/farmacologia , Chromobacterium/efeitos dos fármacos , Cumarínicos/farmacologia , Pseudomonas aeruginosa/efeitos dos fármacos , Percepção de Quorum/efeitos dos fármacos , Antibacterianos/síntese química , Antibacterianos/química , Chromobacterium/química , Cumarínicos/síntese química , Cumarínicos/química , Relação Dose-Resposta a Droga , Indóis/antagonistas & inibidores , Indóis/metabolismo , Testes de Sensibilidade Microbiana , Estrutura Molecular , Relação Estrutura-Atividade
3.
Phys Rev Lett ; 114(1): 015301, 2015 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-25615476

RESUMO

We observe that the diffusive spin current in a strongly interacting degenerate Fermi gas of (40)K precesses about the local magnetization. As predicted by Leggett and Rice, precession is observed both in the Ramsey phase of a spin-echo sequence, and in the nonlinearity of the magnetization decay. At unitarity, we measure a Leggett-Rice parameter γ=1.08(9) and a bare transverse spin diffusivity D(0)(⊥)=2.3(4)ℏ/m for a normal-state gas initialized with full polarization and at one-fifth of the Fermi temperature, where m is the atomic mass. One might expect γ=0 at unitarity, where two-body scattering is purely dissipative. We observe γ→0 as temperature is increased towards the Fermi temperature, consistent with calculations that show the degenerate Fermi sea restores a nonzero γ. Tuning the scattering length a, we find that a sign change in γ occurs in the range 0<(k(F)a)(-1)≲1.3, where k(F) is the Fermi momentum. We discuss how γ reveals the effective interaction strength of the gas, such that the sign change in γ indicates a switching of branch between a repulsive and an attractive Fermi gas.

4.
Anaesthesia ; 70(10): 1171-9, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26179167

RESUMO

Novel devices for small-lumen ventilation may enable effective inspiration and expiratory ventilation assistance despite airway obstruction. In this study, we investigated a porcine model of complete upper airway obstruction. After ethical approval, we randomly assigned 13 anaesthetised pigs either to small-lumen ventilation following airway obstruction (n = 8) for 30 min, or to volume-controlled ventilation (sham setting, n = 5). Small-lumen ventilation enabled adequate gas exchange over 30 min. One animal died as a result of a tension pneumothorax in this setting. Redistribution of ventilation from dorsal to central compartments and significant impairment of the distribution of ventilation/perfusion occurred. Histopathology demonstrated considerable lung injury, predominantly through differences in the dorsal dependent lung regions. Small-lumen ventilation maintained adequate gas exchange in a porcine airway obstruction model. The use of this technique for 30 min by inexperienced clinicians was associated with considerable end-expiratory collapse leading to lung injury, and may also carry the risk of severe injury.


Assuntos
Obstrução das Vias Respiratórias/terapia , Respiração Artificial/métodos , Lesão Pulmonar Aguda/etiologia , Obstrução das Vias Respiratórias/sangue , Obstrução das Vias Respiratórias/fisiopatologia , Animais , Modelos Animais de Doenças , Hemodinâmica/fisiologia , Masculino , Oxigênio/sangue , Pressão Parcial , Troca Gasosa Pulmonar/fisiologia , Respiração Artificial/efeitos adversos , Sus scrofa , Volume de Ventilação Pulmonar/fisiologia , Traqueotomia/métodos
5.
Phys Rev Lett ; 106(2): 025302, 2011 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-21405237

RESUMO

We study the population dynamics of a Bose-Einstein condensate in a double-well potential throughout the crossover from Josephson dynamics to hydrodynamics. At barriers higher than the chemical potential, we observe slow oscillations well described by a Josephson model. In the limit of low barriers, the fundamental frequency agrees with a simple hydrodynamic model, but we also observe a second, higher frequency. A full numerical simulation of the Gross-Pitaevskii equation giving the frequencies and amplitudes of the observed modes between these two limits is compared to the data and is used to understand the origin of the higher mode. Implications for trapped matter-wave interferometers are discussed.

6.
Artigo em Inglês | MEDLINE | ID: mdl-29132023

RESUMO

The determination of regional blood flow via the accumulation of fluorescent microspheres is a concept regularly used in medical research. Typically, the microbeads get extracted from the tissue of interest and are then quantified by measuring the absorption or fluorescence of the incorporated dyes without further separation from the medium. However, in that case the absorption spectra of different dyes can overlap when used simultaneously, leading to an overestimation of the concentration. Additionally, background absorption from the medium can be problematic. Therefore, a high performance liquid chromatography method for the simultaneous detection of four dyes (orange, crimson, yellow-green and red) incorporated in different microbeads in samples from biological media such as organ tissue (brain, heart and kidneys) was developed. Since for biological samples often a large sample size is required for sufficient statistics, the method was optimized to yield very short run times. With this method it was possible to detect very low concentrations of only one microsphere per gram of organ tissue. By applying this sensitive quantification technique, it was demonstrated that the application of microbeads for perfusion measurements might not be reliable due to different organ distributions in each animal.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Corantes Fluorescentes/análise , Animais , Encéfalo/metabolismo , Corantes Fluorescentes/farmacocinética , Rim/metabolismo , Limite de Detecção , Modelos Lineares , Masculino , Microesferas , Miocárdio/metabolismo , Fluxo Sanguíneo Regional , Suínos , Distribuição Tecidual
7.
Neurocirugia (Astur) ; 17(6): 544-9, 2006 Dec.
Artigo em Espanhol | MEDLINE | ID: mdl-17242844
8.
Biochim Biophys Acta ; 438(2): 461-73, 1976 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-8107

RESUMO

Purified acid-thermostable ribonuclease (Ribonucleate 3'-pyrimidino-oligonucleotidohydrolase, EC 3.1.4.22) from human pancreas degrades double-stranded RNA at 2% the rate for single-stranded RNA. The activities against single-stranded RNA and double-stranded RNA were shown to be due to a single enzyme with properties similar to bovine pancreatic RNAase A. For purposes of comparison the activities against double-stranded RNA of crystalline ribonucleases of the whale, rat and cow were assayed and found to be 0.4%, 0.03% and 0.003%, respectively, of their activities against single-stranded RNA. Both human serum and urine contain RNAse components of pancreatic origin which hydrolyze double-stranded RNA at 2% and 0.4%, respectively, of the rates against single-stranded RNA. By contrast, purified acid-thermostable RNAases from human spleen and liver hydrlyze double-stranded RNA at least 20-fold more slowly than human pancreatic RNAase, relative to the corresponding rates against single-stranded RNA. The human pancreatic and serum enzymes exhibit appreciable activity against the poly(C) component of the double-stranded poly(I)-poly(C); they also attack poly(C) itself at approximately 25 times the rate for poly(U) and at more than 50 times the rate for single-stranded RNA.


Assuntos
Pâncreas/enzimologia , Ribonucleases/metabolismo , Animais , Estabilidade de Medicamentos , Humanos , Concentração de Íons de Hidrogênio , Especificidade de Órgãos , Poli I-C , Especificidade da Espécie , Relação Estrutura-Atividade , Temperatura
9.
Phytomedicine ; 22(1): 77-85, 2015 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-25636875

RESUMO

Five dammarane-type triterpenoids, five pentacyclic triterpenoids (three of them carrying a carboxylic acid group), and two aromadendrane-type sesquiterpenoids were isolated from an Argentinian collection of the liverwort Lepidozia chordulifera. Compounds were characterized by comparison of their spectral data with those previously reported and tested in their ability to control bacterial growth, biofilm formation, bacterial Quorum Sensing process (QS), and elastase activity of Pseudomonas aeruginosa, as well as bacterial growth and biofilm formation of Staphylococcus aureus. The key role played by biofilm and elastase activity in bacterial virulence make them a potential target for the development of antibacterial agents. The aromadendrane-type sesquiterpenoid viridiflorol was the most potent biofilm formation inhibitor, producing 60% inhibition in P. aeruginosa and 40% in S. aureus at 50µg/ml. Ursolic and betulinic acids (two of the pentacyclic triterpenoids isolated) were able to reduce 96 and 92% the elastase activity of P. aeruginosa at 50µg/ml, respectively. Among the analyzed triterpenoids, those that carry a dammarane skeleton were the most potent inhibitors of the P. aeruginosa biofilm formation and were active against both P. aeruginosa and S. aureus. Subsequently, a computer-assisted study of the triterpenoid compounds was carried out for a better understanding of the structure-activity relationships.


Assuntos
Biofilmes/efeitos dos fármacos , Hepatófitas/química , Sesquiterpenos/farmacologia , Terpenos/farmacologia , Triterpenos/farmacologia , Inibidores Enzimáticos/farmacologia , Estrutura Molecular , Elastase Pancreática/antagonistas & inibidores , Triterpenos Pentacíclicos , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/enzimologia , Percepção de Quorum/efeitos dos fármacos , Sesquiterpenos/isolamento & purificação , Staphylococcus aureus/efeitos dos fármacos , Relação Estrutura-Atividade , Triterpenos/isolamento & purificação , Ácido Betulínico , Ácido Ursólico
10.
Phytochemistry ; 57(1): 125-30, 2001 May.
Artigo em Inglês | MEDLINE | ID: mdl-11336253

RESUMO

The investigation of an Argentine collection of Enydra anagallis afforded sesquiterpene lactones of the melampolide type two of which were previously known. Their structures were elucidated by spectroscopic methods.


Assuntos
Asteraceae/química , Lactonas/isolamento & purificação , Sesquiterpenos/isolamento & purificação , Lactonas/química , Sesquiterpenos/química , Análise Espectral
11.
Clin Chim Acta ; 101(1): 17-24, 1980 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-7357736

RESUMO

Alkaline acid- and thermo-stable ribonuclease was isolated from human saliva of healthy subjects, children with cystic fibrosis, and from parents of the latter. The enzyme was purified about 180-200 times, and its ionic requirements, and specificity towards various substrates, characterized and compared with those for human pancreatic ribonuclease. The level of acid- and thermo-stable ribonuclease activity was five times higher in terms of enzyme level per ml saliva, and three times higher in terms of salivary protein, for 62% of children with cystic fibrosis, and for 73% of carrier subjects, relative to co-nrol groups. Assay of the level of this ribonuclease activity appears to be a promising diagnostic tool for detection of heterozygote carriers.


Assuntos
Fibrose Cística/enzimologia , Ribonucleases/análise , Saliva/enzimologia , Adulto , Criança , Pré-Escolar , Fibrose Cística/genética , Triagem de Portadores Genéticos , Heterozigoto , Homozigoto , Temperatura Alta , Humanos , Concentração de Íons de Hidrogênio , Pessoa de Meia-Idade , Ribonucleases/antagonistas & inibidores , Ribonucleases/isolamento & purificação , Especificidade por Substrato
12.
Clin Chim Acta ; 133(3): 311-6, 1983 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-6627689

RESUMO

The biochemical composition of saliva secreted by healthy persons and by heterozygotes and homozygotes of cystic fibrosis at rest and by healthy persons subjected to aerobic or anaerobic effort were compared. In the saliva from cystic fibrosis homozygotes at rest substantial increases of the activity of ribonuclease (p less than 0.001) and of the concentrations of protein (p less than 0.001), lactate (p less than 0.001), sodium (p less than 0.001), potassium (p less than 0.01) and calcium (p less than 0.05) were found in comparison with saliva from healthy persons at rest. In the saliva from cystic fibrosis heterozygotes at rest similar but less pronounced changes were seen. After anaerobic exercise these biochemical parameters were increased in the saliva of healthy persons and mimicked the values of cystic fibrosis saliva. However, after aerobic effort no changes other than a slightly increased ribonuclease activity were seen in the saliva of healthy persons. This indicates that salivary glands of cystic fibrosis patients, at rest, are in the same state of lactate acidosis and energy depletion as these glands are in healthy persons after anaerobic work.


Assuntos
Fibrose Cística/metabolismo , Esforço Físico , Saliva/metabolismo , Adolescente , Adulto , Aerobiose , Anaerobiose , Cálcio/metabolismo , Criança , Pré-Escolar , Fibrose Cística/sangue , Heterozigoto , Homozigoto , Humanos , Lactente , Lactatos/metabolismo , Ácido Láctico , Pessoa de Meia-Idade , Potássio/metabolismo , Proteínas/metabolismo , Ribonucleases/metabolismo , Sódio/metabolismo
13.
Clin Chim Acta ; 67(3): 231-43, 1976 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-4243

RESUMO

Acid-thermostable ribonucleases were isolated from human pancreas, duodenal contents, liver, spleen, serum and urine, and purified 15--1000-fold. The pH optima, ionic requirements, and some of the specificity requirements, of these enzymes were investigated. The isolated enzymes formed two distinct groups: (a) The ribonucleases of the pancreas, duodenal contents and fraction A of serum and urine exhibit a pH optimum of 8.5, are inhibited by An2+ and Cu2+, and relatively rapidly hydrolyze the synthetic substrate uridine 3'-(alpha-naphthylphosphate); (b) the ribonucleases of the liver and spleen, and of fractions B of the serum and urine, with a pH optimum of 7, are less sensitive to An2+ and Cu2+, and exhibit negligible activity versus uridine 3'-(alpha-naphthylphosphate). Determination of the serum level of pancreatic-type ribonuclease activity, with the use of uridine 3'-(alpha-naphthylphosphate) or RNA as substrates, appears to be a valid diagnostic tool for pancreatic fibrosis in children.


Assuntos
Fibrose Cística/diagnóstico , Ribonucleases/metabolismo , Criança , Cobre/farmacologia , Fibrose Cística/enzimologia , Duodeno/enzimologia , Humanos , Concentração de Íons de Hidrogênio , Cinética , Fígado/enzimologia , Especificidade de Órgãos , Pâncreas/enzimologia , Ribonucleases/sangue , Ribonucleases/isolamento & purificação , Baço/enzimologia , Zinco/farmacologia
14.
Biochem Syst Ecol ; 29(6): 633-647, 2001 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-11336812

RESUMO

Flowers and leaves of Disynaphia multicrenulata from Argentina afforded a large number of known germacradienolides and heliangolides, a new germacradienolide, a known melampolide, a new parthenolide derivative, one known and seven new cronquistiolides, a new 4Z-melampolide, three known and five new eudesmanolides, a new elemadienolide, a known grazielolide, an isoguaiagrazielolide, two diepoxygermacran-8,12-olides, three common kauranoic acids, pinoresinol, jaceosidin and the sesquiterpene oplopanone. Structures were elucidated by high-field 1H NMR spectrometry. The relationship to the known chemistry of other members of the Disynaphiinae is discussed.

15.
An Sist Sanit Navar ; 27 Suppl 3: 9-16, 2004.
Artigo em Espanhol | MEDLINE | ID: mdl-15723101

RESUMO

Oncology patients do not form a large proportion within the overall figures of an emergency service, but their clinical characteristics mean that attending to them is often complex. The elaboration of a complete clinical history, specifying the characteristics and stage of the tumoural disease, is a basic weapon for taking decisions when an emergency arises. According to the data from our centre, oncology patients account for 5% of the total of emergency cases. The most frequent type of tumour that we deal with is pulmonary, followed by breast and colon. It is often the case that these patients come to the emergency department several times in the same month and pain is the most frequent reason for consultation, although it is normal for them to mention several causes on each occasion. In a high percentage of cases the reason for the consultation is related to the disease itself, but on as many as 35% of occasions it is an intercurrent pathology. The index of admissions is high (around 50%), especially if the patient has come for a reason related to the disease. In global terms, they account for 14% of total admissions from emergencies.


Assuntos
Neoplasias/epidemiologia , Emergências , Humanos , Espanha/epidemiologia
16.
Science ; 344(6185): 722-4, 2014 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-24833387

RESUMO

Understanding the quantum dynamics of strongly interacting fermions is a problem relevant to diverse forms of matter, including high-temperature superconductors, neutron stars, and quark-gluon plasma. An appealing benchmark is offered by cold atomic gases in the unitary limit of strong interactions. Here, we study the dynamics of a transversely magnetized unitary Fermi gas in an inhomogeneous magnetic field. We observe the demagnetization of the gas, caused by diffusive spin transport. At low temperatures, the diffusion constant saturates to the conjectured quantum-mechanical lower bound ≃ h/m, where m is the particle mass. The development of pair correlations, indicating the transformation of the initially noninteracting gas toward a unitary spin mixture, is observed by measuring Tan's contact parameter.

17.
Neotrop Entomol ; 41(5): 414-9, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23950093

RESUMO

Porella, the largest genus of the family Porellaceae (Hepaticae) is widespread in the tropical and subtropical regions of South America. Most Porella species are rich sources of sesqui- and diterpenoids, many of which show interesting biological activities. Secondary metabolites produced by plants can interact with insects and act as antifeedants and growth regulators affecting hormone and nervous systems as well as stomach and muscle tissues. A previous chemical investigation of a Patagonian collection of Porella chilensis yielded sesqui- and diterpenoids that were now evaluated for their effects against Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), a serious pest affecting corn crops mainly in the Americas. Four pinguisanes (1-4), three fusicoccanes (5-7), and one aromadendrane (8) from P. chilensis displayed larvicidal activity against S. frugiperda when incorporated to the larval diet at 100 and 200 µg/g of diet with a significant decrease in the larval growing rate. The observed effects were in part produced by severe alterations of the epithelial cells of the midgut as indicated by our histological studies.


Assuntos
Agentes de Controle Biológico , Diterpenos/toxicidade , Hepatófitas , Sesquiterpenos/toxicidade , Spodoptera/efeitos dos fármacos , Spodoptera/fisiologia , Zea mays/parasitologia , Animais , Larva/efeitos dos fármacos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA