864 resultados para urinary sphincter, artificial
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We describe a device made of artificial muscle for the treatment of end-stage heart failure as an alternative to current heart assist devices. The key component is a matrix of nitinol wires and aramidic fibers called Biometal muscle (BM). When heated electrically, it produces a motorless, smooth, and lifelike motion. The BM is connected to a carbon fiber scaffold, tightening the heart and providing simultaneous assistance to the left and right ventricles. A pacemaker-like microprocessor drives the contraction of the BM. We tested the device in a dedicated bench model of diseased heart. It generated a systolic pressure of 75 mm Hg and ejected a maximum of 330 ml/min, with an ejection fraction of 12%. The device required a power supply of 6 V, 250 mA. This could be the beginning of an era in which BMs integrate or replace the mechanical function of natural muscles.
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Uromodulin is expressed exclusively in the thick ascending limb and is the most abundant protein excreted in normal urine. Variants in UMOD, which encodes uromodulin, are associated with renal function, and urinary uromodulin levels may be a biomarker for kidney disease. However, the genetic factors regulating uromodulin excretion are unknown. We conducted a meta-analysis of urinary uromodulin levels to identify associated common genetic variants in the general population. We included 10,884 individuals of European descent from three genetic isolates and three urban cohorts. Each study measured uromodulin indexed to creatinine and conducted linear regression analysis of approximately 2.5 million single nucleotide polymorphisms using an additive model. We also tested whether variants in genes expressed in the thick ascending limb associate with uromodulin levels. rs12917707, located near UMOD and previously associated with renal function and CKD, had the strongest association with urinary uromodulin levels (P<0.001). In all cohorts, carriers of a G allele of this variant had higher uromodulin levels than noncarriers did (geometric means 10.24, 14.05, and 17.67 μg/g creatinine for zero, one, or two copies of the G allele). rs12446492 in the adjacent gene PDILT (protein disulfide isomerase-like, testis expressed) also reached genome-wide significance (P<0.001). Regarding genes expressed in the thick ascending limb, variants in KCNJ1, SORL1, and CAB39 associated with urinary uromodulin levels. These data indicate that common variants in the UMOD promoter region may influence urinary uromodulin levels. They also provide insights into uromodulin biology and the association of UMOD variants with renal function.
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Microbial mats are complex but stable, multi-layered and multi-functional biofilms, which are the most frequent bacterial formations in nature. The functional strategies and physiological versatility of the bacterial populations growing in microbial mats allow bacteria to resist changing conditions within their environment. One of these strategies is the accumulation of carbon- and energy-rich polymers that permit the recovery of metabolic activities when favorable conditions are restored. In the present study, we systematically screened microbial mats for bacteria able to accumulate large amounts of the ester carbon polymers polyhydroxyalkanoates (PHA). Several of these strains were isolated from Ebro Delta microbial mats and their ability to accumulate PHA up to 40-60 % of their dry weight was confirmed. According to two identification approaches (16S rRNA and ropD genes), these strains were identified as Halomonas alkaliphila (MAT-7, -13, -16), H. neptunia (MAT-17), and H. venusta (MAT-28). To determine the mode of growth yielding maximum PHA accumulation, these three different species were cultured in an artificial biofilm in which the cells were immobilized on alginate beads. PHA accumulation by cells that had detached from the biofilm was compared with that of their planktonic counterparts. Experiments in different culture media showed that PHA accumulation, measured as the relative fluorescence intensity after 48 h of incubation at 30 °C, was higher in immobilized than in planktonic cells, with the exception of cells growing in 5 % NaCl, in which PHA accumulation was drastically lower in both. Therefore, for obtaining high PHA concentrations, the use of immobilized cells may be a good alternative to the PHA accumulation by bacteria growing in the classical, planktonic mode. From the ecological point of view, increased PHA accumulation in detached cells from biofilms would be a natural strategy to improve bacterial dispersion capacity and, consequently, to increase survival in stressed environments.
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Introducción: Hay poco conocimiento sobre la similitud de la mecánica entre la lactancia materna y la artificial. Evaluamos la mecánica de la succión en neonatos con lactancia materna exclusiva, lactancia artificial exclusiva y lactancia mixta. Nuestra hipótesis fue que el patrón fisiológico de los movimientos de succión varía según el tipo de alimentación. Según esta hipótesis, los niños con lactancia materna exclusiva realizan unos movimientos al mamar distintos a los de la succión de una tetina, realizados por niños con lactancia artificial. Los niños con lactancia mixta mezclan ambos tipos de movimientos de succión. Métodos: Estudio transversal de neonatos de 21-28 días de edad con lactancia materna o artificial exclusiva (124 parejas madre-hijo), y ensayo de campo, abierto, cruzado y aleatorizado, realizado en neonatos de 21-28 días (110 parejas madre-hijo) y en lactantes de 3-5 meses de edad (125 parejas madre-hijo) con lactancia mixta. Las variables principales fueron los movimientos de succión y las pausas. Resultados: Los neonatos de 21-28 días de edad alimentados con lactancia artificial exclusiva mostraron un menor número de movimientos de succión y el mismo número de pausas, pero de mayor duración, que los neonatos con lactancia materna exclusiva. Entre los niños que recibieron lactancia mixta, el número de movimientos de succión al recibir alimentación con biberón fue similar y las pausas menos numerosas y de menor duración respecto a lo observado al amamantar, tanto a los 21-28 días como a los 3-5 meses de edad. En este grupo de lactancia mixta, la cifra media de tomas de lactancia materna fue de 5,83 ± 1,93 a los 21-28 días de vida y de 4,42 ± 1,67 a los 3-5 meses de edad. En el análisis de equivalencia, realizado sobre los niños que recibieron lactancia mixta, el intervalo de confianza del 95% de la razón de movimientos con lactancia artificial y con lactancia materna se situó fuera del rango de equivalencia, indicó un número de movimientos de succión menor en un 5,9-8,7% al tomar el biberón, así como un menor número de pausas y una duración más breve de ellas en este mismo grupo. Conclusiones: En la lactancia mixta, la comparación entre las tomas de biberón y las de pecho se situó fuera del rango de equivalencia, aunque las diferencias fueron pequeñas. Los niños con lactancia mixta mezclan ambos tipos de movimientos (lactancia materna y lactancia artificial) durante la fase de aprendizaje y adoptan su propio patrón.
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Drug screening is an important issue in clinical and forensic toxicology. Gas chromatography coupled to mass spectrometry (GC-MS) remains the gold standard technique for the screening of unknown compounds in urine samples. However, this technique requires substantial sample preparation, which is time consuming. Moreover, some common drugs such as cannabis cannot be easily detected in urine using general procedures. In this work, a sample preparation protocol for treating 200 μL of urine in less than 30 min is described. The enzymatic hydrolysis of glucuro-conjugates was performed in 5 min thanks to the use of microwaves. The use of a deconvolution software allowed reducing the GC-MS run to 10 min, without impairing the quality of the compound identifications. Comparing the results from 139 authentic urine samples to those obtained using the current routine analysis indicated this method performed well. Moreover, additional 5-min GC-MS/MS programs are described, enabling a very sensitive target screening of 54 drugs, including THC-COOH or buprenorphine, without further sample preparation. These methods appeared as an interesting alternative to immuno-assays based screening. The analytical strategy presented in this article proved to be a promising approach for systematic toxicological analysis (STA) of drugs in urine.
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O teste de envelhecimento artificial, recomendado para avaliar o vigor de lotes de sementes, apresenta variabilidade em seus resultados; a ação dos fungos é considerada uma das causas dessa variabilidade. Este trabalho objetivou verificar os efeitos de diferentes períodos de envelhecimento artificial, no comportamento fisiológico de sementes do feijoeiro e dos fungos Aspergillus spp., Penicillium spp., Fusarium oxysporum e Colletotrichum lindemuthianum, inoculados artificialmente. Foram conduzidos testes de sanidade, germinação, tetrazólio, emergência, condutividade elétrica e lixiviação de potássio. As respostas obtidas, dependentes da duração do período de envelhecimento, indicaram efeitos da espécie fúngica presente. Concluiu-se que o teste de envelhecimento artificial associa a expressão de causas fisiológicas e sanitárias, o que prejudica a interpretação dos dados obtidos; a presença de fungos, principalmente de Aspergillus spp., pode ser considerada como capaz de interferir de modo negativo no desempenho das sementes envelhecidas artificialmente.
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Intake of caffeinated beverages might be associated with reduced cardiovascular mortality possibly via the lowering of blood pressure. We estimated the association of ambulatory blood pressure with urinary caffeine and caffeine metabolites in a population-based sample. Families were randomly selected from the general population of Swiss cities. Ambulatory blood pressure monitoring was conducted using validated devices. Urinary caffeine, paraxanthine, theophylline, and theobromine excretions were measured in 24 hours urine using ultrahigh performance liquid chromatography tandem mass spectrometry. We used mixed models to explore the associations of urinary excretions with blood pressure although adjusting for major confounders. The 836 participants (48.9% men) included in this analysis had mean age of 47.8 and mean 24-hour systolic and diastolic blood pressure of 120.1 and 78.0 mm Hg. For each doubling of caffeine excretion, 24-hour and night-time systolic blood pressure decreased by 0.642 and 1.107 mm Hg (both P values <0.040). Similar inverse associations were observed for paraxanthine and theophylline. Adjusted night-time systolic blood pressure in the first (lowest), second, third, and fourth (highest) quartile of paraxanthine urinary excretions were 110.3, 107.3, 107.3, and 105.1 mm Hg, respectively (P trend <0.05). No associations of urinary excretions with diastolic blood pressure were generally found, and theobromine excretion was not associated with blood pressure. Anti-hypertensive therapy, diabetes mellitus, and alcohol consumption modify the association of caffeine urinary excretion with systolic blood pressure. Ambulatory systolic blood pressure was inversely associated with urinary excretions of caffeine and other caffeine metabolites. Our results are compatible with a potential protective effect of caffeine on blood pressure.
Resumo:
Introducción: Hay poco conocimiento sobre la similitud de la mecánica entre la lactancia materna y la artificial. Evaluamos la mecánica de la succión en neonatos con lactancia materna exclusiva, lactancia artificial exclusiva y lactancia mixta. Nuestra hipótesis fue que el patrón fisiológico de los movimientos de succión varía según el tipo de alimentación. Según esta hipótesis, los niños con lactancia materna exclusiva realizan unos movimientos al mamar distintos a los de la succión de una tetina, realizados por niños con lactancia artificial. Los niños con lactancia mixta mezclan ambos tipos de movimientos de succión. Métodos: Estudio transversal de neonatos de 21-28 días de edad con lactancia materna o artificial exclusiva (124 parejas madre-hijo), y ensayo de campo, abierto, cruzado y aleatorizado, realizado en neonatos de 21-28 días (110 parejas madre-hijo) y en lactantes de 3-5 meses de edad (125 parejas madre-hijo) con lactancia mixta. Las variables principales fueron los movimientos de succión y las pausas. Resultados: Los neonatos de 21-28 días de edad alimentados con lactancia artificial exclusiva mostraron un menor número de movimientos de succión y el mismo número de pausas, pero de mayor duración, que los neonatos con lactancia materna exclusiva. Entre los niños que recibieron lactancia mixta, el número de movimientos de succión al recibir alimentación con biberón fue similar y las pausas menos numerosas y de menor duración respecto a lo observado al amamantar, tanto a los 21-28 días como a los 3-5 meses de edad. En este grupo de lactancia mixta, la cifra media de tomas de lactancia materna fue de 5,83 ± 1,93 a los 21-28 días de vida y de 4,42 ± 1,67 a los 3-5 meses de edad. En el análisis de equivalencia, realizado sobre los niños que recibieron lactancia mixta, el intervalo de confianza del 95% de la razón de movimientos con lactancia artificial y con lactancia materna se situó fuera del rango de equivalencia, indicó un número de movimientos de succión menor en un 5,9-8,7% al tomar el biberón, así como un menor número de pausas y una duración más breve de ellas en este mismo grupo. Conclusiones: En la lactancia mixta, la comparación entre las tomas de biberón y las de pecho se situó fuera del rango de equivalencia, aunque las diferencias fueron pequeñas. Los niños con lactancia mixta mezclan ambos tipos de movimientos (lactancia materna y lactancia artificial) durante la fase de aprendizaje y adoptan su propio patrón.
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Laboratory and greenhouse studies were conducted with an artificial dry diet to rear nymphs, and with an artificial plant as substrate for egg laying by the southern green stink bug, Nezara viridula (L.). The artificial diet was composed of: soybean protein (15 g); potato starch (7.5 g); dextrose (7.5 g); sucrose (2.5 g); cellulose (12.5 g); vitamin mixture (niacinamide 1 g, calcium pantothenate 1 g, thiamine 0.25 g, riboflavin 0.5 g, pyridoxine 0.25 g, folic acid 0.25 g, biotin 0.02 mL, vitamin B12 1 g - added to 1,000 mL of distilled water) (5.0 mL); soybean oil (20 mL); wheat germ (17.9 g); and water (30 mL). Nymphs showed normal feeding behavior when fed on the artificial diet. Nymphal development time was longer than or similar to that of nymphs fed on soybean pods. Total nymphal mortality was low (ca. 30%), both for nymphs reared on the artificial diet, and for nymphs fed on soybean pods. At adult emergence, fresh body weights were significantly (P<0.01) less on the artificial diet than on soybean pods. Despite the lower adult survivorship and fecundity on artificial plants than on soybean plants, it was demonstrated for the first time that a model simulating a natural plant, can be used as a substrate for egg mass laying, in conjunction with the artificial diet.
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O objetivo deste trabalho foi a obtenção de híbridos de amendoim forrageiro por meio da hibridação artificial. O experimento foi realizado na Embrapa-Centro Nacional de Pesquisa de Recursos Genéticos e Biotecnologia, durante a época de florescimento dos acessos de Arachis pintoi Krap. & W. C. Gregory e de A. repens Handro. Cerca de 700 polinizações produziram 27 segmentos de frutos, com taxas de fecundação que variaram entre 1,1 e 12,9%, considerando-se todas as combinações híbridas. Os híbridos intra-específicos de A. pintoi produziram sementes F2, e os interespecíficos não produziram semente. A técnica de hibridação utilizada nas espécies forrageiras necessitou de ajustes, devido a diferenças observadas em relação ao amendoim cultivado, entre elas o hábito de crescimento.
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O presente trabalho objetivou avaliar a eficácia do tratamento Ovsynch associado à inseminação artificial em tempo prefixado em vacas Bos taurus e Bos indicus. Foram utilizados rebanhos das raças Holandesa, Caracu, Nelore e Mantiqueira. Também foi incluído um rebanho de vacas Gir, com problemas de fertilidade. Cada rebanho foi dividido em três grupos. O grupo 1 recebeu o tratamento Ovsynch e foi inseminado em tempo prefixado. O grupo 2 foi inseminado no cio induzido com cloprostenol. O grupo 3 foi inseminado no cio natural. As taxas de concepção e de prenhez foram determinadas por ultra-sonografia. Não existiu interação significativa das variáveis reprodutivas analisadas para rebanho, idade, período pós-parto, número de parição e presença do bezerro. A taxa de concepção não diferiu (P>0,05) entre os grupos, ao passo que a taxa de prenhez foi superior (P<0,05) nos grupos 1 e 2 em comparação ao grupo 3. No rebanho Gir, o tratamento Ovsynch não alterou a taxa de concepção nem a de prenhez. Independentemente da raça, os tratamentos Ovsynch e cloprostenol não afetam a taxa de concepção, mas melhoram a taxa de prenhez. O tratamento Ovsynch não aumenta a fertilidade de vacas com problemas reprodutivos inespecíficos.
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Artificial radionuclides ((137)Cs, (90)Sr, Pu, and (241)Am) are present in soils because of Nuclear Weapon Tests and accidents in nuclear facilities. Their distribution in soil depth varies according to soil characteristics, their own chemical properties, and their deposition history. For this project, we studied the atmospheric deposition of (137)Cs, (90)Sr, Pu, (241)Am, (210)Pb, and stable Pb. We compared the distribution of these elements in soil profiles from different soil types from an alpine Valley (Val Piora, Switzerland) with the distribution of selected major and trace elements in the same soils. Our goals were to explain the distribution of the radioisotopes as a function of soil parameters and to identify stable elements with analogous behaviors. We found that Pu and (241)Am are relatively immobile and accumulate in the topsoil. In all soils, (90)Sr is more mobile and shows some accumulations at depth into Fe-Al rich horizons. This behavior is also observed for Cu and Zn, indicating that these elements may be used as chemical analogues for the migration of (90)Sr into the soil.