641 research outputs found

    Dislocations in Si-Doped LEC GaAs Revisited: a Spectrum Image Cathodoluminescence Study

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    The understanding of the role of impurities is crucial to semiconductor device technology, since all the devices are engineered by the selective incorporation of impurities. However, the incorporation of these impurities to the lattice and the resulting free charge concentration depend on the interaction with native defects. Dislocations in Si-doped substrates were studied in the nineties using highly sensitive DSL (Diluted Sirtl-Like) etching, SEM-EBIC (Electron Beam Induced Current) and microPL techniques. Both grown-in (G) dislocations, and grown-in dislocations glided (GS) by thermal stresses during post growth cooling were investigated aiming to understand the interaction between the dislocations and the doped GaAs matrix. CL spectrum imaging allows revisiting this problem supplying information about the defects forming the Cottrell atmospheres, and how they are distributed. By using a CCD multichannel detector it is possible to obtain the full spectral information over a selected area with submicrometric spatial resolution. The local spectra corresponding to the different regions of the dislocation atmosphere are available, allowing the identification of the different defects responsible for the luminescence emission. On the other hand, the use of fitting routines allows mapping the distribution of the different defects and impurities, providing a full scenario of the Cottrell atmosphere. The CL images are complemented with etching depth (using DSL) images obtained by Phase Stepping Microscopy

    Mercado de formaci?n y disponibilidad de profesionales de ciencias de la salud en el Per?

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    Objectives. To describe the availability and demand of professional training programs for eight health science professions in Peru. Study the profiles of the physicians, nurses and midwives that these programs train and their competencies to work at the primary health care level. Materials and methods. Cross-sectional study using data on the volume of applicants, students and graduates of these eight professional training programs during the period 2007 - 2011. In addition, the curricula of professional training programs for physicians, nurses and midwives from public and private universities were analyzed, along with competency profiles developed by Professional Colleges and the Ministry of Health. Results. Admission rates in public and private universities vary by program: 4% and 28% respectively for medical schools, and 18% and 90% for nursing. Graduation rates were estimated at approximately 43% and 53% of students entering medicine and nursing training programs respectively. Contrasting the profiles of recently graduated professionals in medicine, nursing and midwifery, with the skills required by the Ministry of Health for professionals working in primary care the first level of care, indicate that these recently graduated professionals are not necessarily or specifically trained to work in primary care. Conclusions. Demand for professional training in health sciences exists and its supply is met predominantly by private universities. Competency profiles developed by the MOH for the basic professional health team in primary care shows a clear disconnect regarding the current supply of trained professionals.Objetivos. Describir el mercado de formaci?n y la disponibilidad de profesionales de ocho carreras de ciencias de la salud en Per?. Adem?s, examinar los perfiles de los m?dicos, enfermeros y obstetras que se forman y sus competencias para trabajar en el primer nivel de atenci?n. Materiales y m?todos. Estudio transversal utilizando datos de volumen de postulantes, ingresantes y graduados de ocho profesiones durante el periodo de 2007?2011. Tambi?n se analizaron los planes de estudio de programas de formaci?n de m?dicos, enfermeros y obstetras de universidades p?blicas y privadas, y los perfiles de competencias elaborados por los colegios profesionales y el Ministerio de Salud (MINSA). Resultados. Las tasas de ingreso en universidades p?blicas y privadas var?an seg?n la carrera: 4 y 28% respectivamente para Medicina Humana, y 18 y 90% para Enfermer?a. Adem?s, se estima que se grad?an aproximadamente 43 y 53% de los estudiantes que ingresan a Medicina y Enfermer?a, respectivamente. El an?lisis del perfil de los profesionales recientemente graduados en Medicina, Enfermer?a y Obstetricia, al ser contrastados con el perfil de competencias priorizadas para los profesionales que laboran en el primer nivel de atenci?n elaborado por el MINSA, indican que no est?n necesariamente ni espec?ficamente formados para trabajar en este nivel de atenci?n. Conclusiones. Existe demanda de formaci?n para profesionales de ciencias de la salud y predomina la oferta por parte de universidades privadas. Los perfiles de competencias desarrollados por el MINSA muestran un claro divorcio con respecto a la oferta actual de profesionales formados

    The Harvey–Bradshaw Index adapted to a mobile application compared with In-clinic assessment: the MediCrohn Study

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    [Abstract] Objectives: Mobile apps are useful tools in e-health and self-management strategies in disease monitoring. We evaluated the Harvey–Bradshaw index (HBI) mobile app self-administered by the patient to see if its results agreed with HBI in-clinic assessed by a physician. Methods: Patients were enrolled in a 4-month prospective study with clinical assessments at months 1 and 4. Patients completed mobile app HBI and within 48 h, HBI was performed by a physician (gold standard). HBI scores characterized Crohn's disease (CD) as remission <5 or active ≥5. We determined agreement per item and total HBI score and intraclass correlation coefficients (ICCs). Bland–Altman plot was performed. HBI changes in disease activity from month 1 to month 4 were determined. Results: A total of 219 patients were enrolled. All scheduled assessments (385 pairs of the HBI questionnaire) showed a high percentage of agreement for remission/activity (92.4%, κ = 0.796), positive predictive value (PPV) for remission of 98.2%, and negative predictive value of 76.7%. High agreement was also found at month 1 (93.15%, κ = 0.82) and month 4 (91.5%, κ = 0.75). Bland–Altman plot was more uniform when the HBI mean values were <5 (remission). ICC values were 0.82, 0.897, and 0.879 in all scheduled assessments, 1 and 4 months, respectively. Conclusions: We found a high percentage of agreement between patients' self-administered mobile app HBI and in-clinic physician assessment to detect CD activity with a remarkably high PPV for remission. The mobile app HBI might allow a strict control of inflammation by remote monitoring and flexible follow-up of CD patients. Reduction of sanitary costs could be possible

    The subpopulation pattern of eel sperm is affected by post-activation time, hormonal treatment and thermal regime

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    [EN] There has been a marked reduction in natural stocks of eels (genus Anguilla) over the past 60 years, and the culture of eels is still based on the capture of very large quantities of juveniles. It is necessary to close the life cycle in captivity in order to ease the pressure on wild populations. The aims of the present study were to evaluate sperm subpopulations (through cluster analysis of computer-aided sperm analysis data) in the European eel (Anguilla anguilla) and to assess the effects of motility acquisition time after activation (i.e. at 30, 60 and 90 s), the thermal regimen (i.e. 10 degrees C (T10) or 15 degrees C (T15) and up to 20 degrees C, or constant at 20 degrees C (T20)) and hormonal treatments (i.e. human chorionic gonadotropin (hCG), recombinant (r) hCG or pregnant mare serum gonadotropin (PMSG)) on these subpopulations. In all cases, we obtained three subpopulations of spermatozoa: low velocity and linear (S1); high velocity with low linearity (S2); and high velocity and linear (S3; considered high quality). Total motility and S1 were affected by acquisition time; thus, 30 s is recommended as the standard time for motility acquisition. When eels were kept at 20 degrees C (T20), motility data fitted quadratic models, with the highest motility and proportion of S3 between Weeks 8 and 12 after the first injection. Lower temperatures (T10, T15) delayed spermiation and the obtaining of high-quality spermatozoa (S3), but did not seem to alter the spermiation process (similar subpopulation pattern). Conversely, the hormonal treatments altered both the dynamics of the subpopulation pattern and the onset of spermiation (with PMSG delaying it). Total motility and the yield of S3 with the widely used hCG treatment varied throughout the spermiation period. However, using rhCG allowed us to obtain high-quality and constant motility for most of the study (Weeks 7-20), and the S3 yield was also higher overall (61.8 +/- 1.3%; mean +/- s.e.m.) and more stable over time than the other hormonal treatments (averaging 53.0 +/- 1.4%). Using T20 and rhCG would be more economical and practical, allowing us to obtain a higher number of S3 spermatozoa over an extended time.This study was funded by the European Community's 7th Framework Program under the Theme 2 'Food, Agriculture and Fisheries, and Bio-technology', grant agreement no. 245257 (PRO-EEL) and Generalitat Valenciana (ACOMP/2012/086). VG and MCV have predoctoral grants from the Spanish Ministry of Economy and Competitiveness (AGL2010-16009) and Universitat Politecnica de Valencia (UPV) PAID Program (2011-S2-02-6521), respectively. DSP was supported by a contract cofinanced by Ministry of Science and Innovation (MICINN) and UPV (PTA2011-4948-I). FM-P was supported by the Ramon y Cajal program (MICINN, RYC-2008-02560).Gallego Albiach, V.; Vilchez Olivencia, MC.; Peñaranda, D.; Pérez Igualada, LM.; Herraez, MP.; Asturiano Nemesio, JF.; Martinez-Pastor, F. (2015). The subpopulation pattern of eel sperm is affected by post-activation time, hormonal treatment and thermal regime. Reproduction, Fertility and Development. 27(3):529-543. https://doi.org/10.1071/RD13198S52954327

    Improved Vascular Engraftment and Graft Function After Inhibition of the Angiostatic Factor Thrombospondin-1 in Mouse Pancreatic Islets

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    OBJECTIVE—Insufficient development of a new intra-islet capillary network after transplantation may be one contributing factor to the failure of islet grafts in clinical transplantation. The present study tested the hypothesis that the angiostatic factor thrombospondin-1 (TSP-1), which is normally present in islets, restricts intra-islet vascular expansion posttransplantation

    Different ways to die: cell death modes of the unicellular chlorophyte Dunaliella viridis exposed to various environmental stresses are mediated by the caspase-like activity DEVDase

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    Programmed cell death is necessary for homeostasis in multicellular organisms and it is also widely recognized to occur in unicellular organisms. However, the mechanisms through which it occurs in unicells, and the enzymes involved within the final response is still the subject of heated debate. It is shown here that exposure of the unicellular microalga Dunaliella viridis to several environmental stresses, induced different cell death morphotypes, depending on the stimulus received. Senescent cells demonstrated classical and unambiguous apoptotic-like characteristics such as chromatin condensation, DNA fragmentation, intact organelles, and blebbing of the cell membrane. Acute heat shock caused general swelling and altered plasma membrane, but the presence of chromatin clusters and DNA strand breaks suggested a necrotic-like event. UV irradiated cells presented changes typical for necrosis, together with apoptotic characteristics resembling an intermediate cell-death phenotype termed aponecrosis-like. Cells subjected to hyperosmotic shock revealed chromatin spotting without DNA fragmentation, and extensive cytoplasmic swelling and vacuolization, comparable to a paraptotic-like cell death phenotype. Nitrogen-starved cells showed pyknosis, blebbing, and cytoplasmic consumption, indicating a similarity to autophagic/vacuolar-like cell death. The caspase-like activity DEVDase was measured by using the fluorescent substrate Ac-DEVD-AMC and antibodies against the human caspase-3 active enzyme cross-reacted with bands, the intensity of which paralleled the activity. All the environmental stresses tested produced a substantial increase in both DEVDase activity and protein levels. The irreversible caspase-3 inhibitor Z-DEVD-FMK completely inhibited the enzymatic activity whereas serine and aspartyl proteases inhibitors did not. These results show that cell death in D. viridis does not conform to a single pattern and that environmental stimuli may produce different types of cell death depending on the type and intensity of the stimulus, all of which help to understand the cell death-dependent and cell death-independent functions of caspase-like proteins. Hence, these data support the theory that alternative, non-apoptotic programmed cell death (PCDs), exist either in parallel or in an independent manner with apoptosis and were already present in single-celled organisms that evolved some 1.2-1.6 billion years ago
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