4,737 research outputs found

    Interplay between antiferromagnetic order and spin polarization in ferromagnetic metal/electron-doped cuprate superconductor junctions

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    Recently we proposed a theory of point-contact spectroscopy and argued that the splitting of zero-bias conductance peak (ZBCP) in electron-doped cuprate superconductor point-contact spectroscopy is due to the coexistence of antiferromagnetic (AF) and d-wave superconducting orders [Phys. Rev. B {\bf 76}, 220504(R) (2007)]. Here we extend the theory to study the tunneling in the ferromagnetic metal/electron-doped cuprate superconductor (FM/EDSC) junctions. In addition to the AF order, the effects of spin polarization, Fermi-wave vector mismatch (FWM) between the FM and EDSC regions, and effective barrier are investigated. It is shown that there exits midgap surface state (MSS) contribution to the conductance to which Andreev reflections are largely modified due to the interplay between the exchange field of ferromagnetic metal and the AF order in EDSC. Low-energy anomalous conductance enhancement can occur which could further test the existence of AF order in EDSC. Finally, we propose a more accurate formula in determining the spin polarization value in combination with the point-contact conductance data.Comment: 9 pages, 8 figure

    Fiber-top atomic force microscope

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    We present the implementation of an atomic force microscope (AFM) based on fiber-top design. Our results demonstrate that the performances of fiber-top AFMs in contact mode are comparable to those of similar commercially available instruments. Our device thus represents an interesting\ud alternative to existing AFMs, particularly for applications outside specialized research laboratories, where a compact, user-friendly, and versatile tool might often be preferred

    Aging and hyponutrition; A challenge for the sustainability of the NHS: Conclusions of the 9th abbot-SENPE debate forum

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    La desnutrición es un problema común en todos los niveles de atención sanitaria, desde atención primaria a especializada y en centros de atención geriátrica. Su incidencia en los hospitales es del 40% y en las residencias de mayores supera el 60%. Esto último es de gran importancia, tienen una alta relación con el progresivo envejecimiento de la población europea, y es la mayor y más frecuente causa de discapacidad en la población anciana que vive en su domicilio o en instituciones. Países como Holanda, Dinamarca o el Reino Unido han desarrollado Planes Estratégicos Integrales para luchar contra la desnutrición desarrollando e implantando guías, estableciendo cribados obligatorios en los ingresos y altas hospitalarias, en las residencias en ancianos, etc. En nuestro país, en una acción conjunta de SENPE y la Fundación Abbott, estamos desarrollando un Plan Estratégico Integral (Proyecto + nutridos) en el que establecemos recomendaciones claras, precisas y validadas para efectuar cribaje nutricional tanto en pacientes hospitalizados, como en los institucionalizados y en los mayores ambulatorios. En este tema deben de ser tenidos en cuenta los aspectos sociales y financieros. La desnutrición es con mucha frecuencia deficientemente reconocida y tratada. Ello tiene un impacto negativo sobre los pacientes individuales en términos de morbilidad, mortalidad, independencia y calidad de vida, y sobre los sistemas de cuidado sanitario en términos de uso de recursos y costesHyponutrition is a common problem at all health care levels, from primary to specialized care, as well as in geriatric care. Its incidence in a hospital setting is 40% and 60% in nursing homes. This is very important, it is highly related with progressive aging of the European population, and is the biggest and most frequent cause of disability among the elderly population living at home or institutions. Countries such as Holland, Denmark, or the United Kingdom have developed Comprehensive Strategic Plans to fight against hyponutrition by developing and implementing guidelines, establishing mandatory screenings at the moment of hospital admission and discharge, at nursing homes, etc. In our country, a combined action of SENPE and Abbott Foundation is developing a Comprehensive Strategic Plan (+ nutridos Project) in which clear, precise, and validated recommendations are established to perform nutritional screening both in hospitalized patients and institutionalized and ambulatory elderly people. This issue has to take into account the social and financial aspects. Hyponutrition is many times insufficiently recognized and treated. This has a negative impact on the individual patient in terms of morbidity, mortality, independence, and quality of life, as well as on the health care systems in terms of use of health care resources and cost

    LIGHT AND ELECTRON MICROSCOPIC RADIOAUTOGRAPHY OF HEPATIC CELL NUCLEOLI IN MICE TREATED WITH ACTINOMYCIN D

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    Nucleolar partition induced by actinomycin D was used to demonstrate some aspects of nucleolar RNA synthesis and release in mouse hepatic cells, with light and electron microscopic radioautography. The effect of the drug on RNA synthesis and nucleolar morphology was studied when actinomycin D treatment preceded labeling with tritiated orotic acid. Nucleolar partition, consisting of a segegration into granular and fibrillar parts was visible if a dosage of 25 µg of actinomycin D was used, but nucleolar RNA was still synthesized. After a dosage of 400 µg of actinomycin D, nucleolar RNA synthesis was completely stopped If labeling with tritiated orotic acid preceded treatment with 400 µg of actinomycin D, labeled nucleolar RNA was present 15 min after actinomycin D treatment while high resolution radioautography showed an association of silver grains with the granular component. At 30 min after actinomicyn D treatment all labeling was lost. Since labeling was associated with the granular component the progressive loss of label as a result of actinomycin D treatment indicated a release of nucleolar granules. The correlation between this release and the loss of 28S RNA from actinomycin D treated nucleoli as described in the literature is discussed

    The effects of 5-fluorouracil and interferon-alpha on early healing of experimental intestinal anastomoses.

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    The continuing search for effective adjuvant therapy after resection of intestinal malignancies has prompted a growing interest in both immediate post-operative regional chemotherapy and the combination of 5-fluorouracil (5-FU) and interferon-alpha as drugs of choice. We have compared the effects of both compounds, alone and together, on early healing of intestinal anastomoses. Four groups (n = 26 each) of rats underwent resection and anastomosis of both ileum and colon: a control group and three groups receiving intraperitoneal 5-FU, interferon-alpha or both on the day of surgery and the next 2 days. Animals were killed 3 or 7 days (n = 10 each) after operation in order to measure anastomotic strength and hydroxyproline content. The remaining six animals in each group were used to study anastomotic collagen synthetic capacity at day 3. Three days after operation, ileal anastomotic bursting pressure was lowered by 37% in the 5-FU/interferon-alpha group (P = 0.0104). At day 7, anastomotic breaking strength was reduced significantly in ileum (P = 0.0221) and colon (P = 0.0054) of the 5-FU/interferon-alpha group and in colon of the interferon-alpha group (P = 0.0221). Collagen synthetic capacity was strongly suppressed by 5-FU but not by interferon-alpha. However, no differences in anastomotic hydroxyproline content were observed between groups at both days 3 and 7. Thus, post-operative use of interferon-alpha, in particular in combination with 5-FU, may be detrimental to anastomotic repair in the intestine
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