227 research outputs found

    The position of a duodenal diverticulum in the area of the major duodenal papilla and its potential clinical implications

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    Background: Although duodenal diverticula are associated with less frequent pathology than the colonic diverticula in the large intestine, their periampullary position may have significant clinical implications. The aim of the study was to identify any possible correlation between the type of localisation of the major duodenal papilla, duodenal diverticula, and some particular clinical issues. Materials and methods: In total, 628 patients (408 females and 220 males; aged 21–91 years), who underwent endoscopic retrograde cholangiopancreatography were included in this study. The patients were divided into two groups: a study group comprising 66 (10.5%) patients with periampullary position of diverticula (group A), and a control group comprising 562 (89.5%) patients without diverticula (group B). Results: A duodenal diverticulum was diagnosed in the periampullary position in 66/628 (10.5%) patients: 41 women (aged 52–91 years) and 25 men (aged 54–83 years). Conclusions: Three types of localisation were observed for the major duodenal papilla with regard to the diverticula, with the most common type being next to each other (type III). In patients with diverticula, similar frequencies of gallstone occurrence are observed in men and women. Patients with papilla in the diverticulum who underwent cholecystectomy are more prone to develop lithiasis

    Discriminación de aceites de oliva comestibles mediante espectroscopía de fluorescencia sincrónica y análisis multivariante

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    The potential of fluorescence spectroscopy for the classification of olive oils was investigated. Synchronous fluorescence spectra were collected in the region of 240-700 nm with the wavelength intervals of 10, 30, 60 and 80 nm. Successive projection algorithm (SPA) was applied for the determination of representative wavelengths while the linear discriminant analysis (LDA) method was used to classify olive oils. The classification error of the method was low (0,9-6,4%) for measurements collected at all wavelength intervals. The best classification accuracy was obtained for synchronous fluorescence intensities acquired at 10 selected wavelengths with the wavelength interval equal to 10 nm.Se ha investigado el potencial de la espectroscopía de fluorescencia para la clasificación de los aceite de oliva. Para ello, se recogieron espectros de fluorescencia sincrónica en el rango de 240-700 nm con intervalos de longitud de onda de 10, 30, 60 y 80 nm. Las proyecciones algorítmicas sucesivas (SPA) se aplicaron para la determinación de las longitudes de onda representativas mientras que el método de análisis discriminante lineal (LDA) se empleó para clasificar los aceites de oliva. Se obtuvo un error de clasificación del método bajo (0,9-6,4%) para las medidas recogidas en todos los intervalos de onda. La mejor precisión de clasificación se obtuvo para intensidades de fluorescencia sincrónica adquiridos a 10 longitudes de onda seleccionadas con intervalos de longitud de onda de 10 nm

    Demographic and clinical profile of patients with multiple sclerosis diagnosed over the last 30 years according to different diagnostic criteria

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    The aim of this study was to investigate the demographic and clinical characteristics of patients with multiple sclerosis (MS) diagnosed between 1986 and 2015. 333 patients with definite MS were divided into four subgroups according to the following diagnostic criteria: Group A) Poser (n = 145), Group B) McDonald 2000 (n = 66), Group C) McDonald 2005 (n = 62), and Group D) McDonald 2010 (n = 60). We investigated: 1) patient sex and age at diagnosis, 2) symptoms and number of relapses that prompted MS diagnosis, 3) time between first symptoms suggestive of MS and confirmed diagnosis, and 5) Expanded Disability Status Scale (EDSS) score at disease onset. The overall female-to-male ratio was 2.3:1, but in the subgroups it differed significantly (A — 1.9; B — 1.6; C — 4.7; D — 3.6). The mean age at diagnosis (in years) decreased from 39.6 ± 13.3 in Group A to 29.9 ± 9.3 in Group D, p < 0.001. Pyramidal signs remained the most common manifestation regardless of the diagnostic criteria, although an increased trend of visual dysfunction was observed (A — 16%, B — 14%, C — 19%, D — 23,3%; A vs D, p < 0.001). The number of relapses before diagnosis decreased from median 4.0 to 2.5 in Group A and Group D, p < 0.001. Time from the first symptom to diagnosis shortened from 88.9 ± 80.2 months (Group A) to 33.6 ± 68.2 months (Group D), p < 0.0001. Mean EDSS score at diagnosis also decreased: A — 4.4 ± 2.3; B — 3.1 ± 1.7; C — 2.7 ± 1.3; D — 2.8 ± 1.4, p < 0.001. Our study indicates significant differences in demographic and clinical characteristics of MS diagnosed according to the changing criteria

    Experimental research of high field pinning centers in 2% C doped MgB2 wires at 20K and 25K

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    High field pinning centers in MgB doped with 2 at. % carbon under a low and a high hot isostatic pressures have been investigated by transport measurements. The field dependence of the transport critical current density was analyzed within the different pinning mechanisms: surface pinning, point pinning, and pinning due to spatial variation in the Ginzburg-Landau parameter (Δκ pinning). Research indicates that a pressure of 1 GPa allows similar pinning centers to Δκ pinning centers to be obtained. This pinning is very important, because it makes it possible to increase the critical current density in high magnetic fields at 20 K and 25 K. Our results indicate that the δT and δl pinning mechanisms, which are due to a spatial variation in the critical temperature (T) and the mean free path, l, respectively, create dislocations. The high density of dislocations with inhomogeneous distribution in the structure of the superconducting material creates the δl pinning mechanism. The low density of dislocations with inhomogeneous distribution creates the δT pinning mechanism. Research indicates that the hot isostatic pressure process makes it possible to obtain a high dislocation density with a homogeneous distribution. This allows us to obtain the δT pinning mechanism in MgB wires. In addition, a high pressure increases the crossover field from the single vortex to the small vortex bundle regime (B) and improves the δT pinning mechanism. Our research has proved that a high pressure significantly increases the crossover field from the small bundle to the thermal regime (B), with only a modest decrease in T of 1.5 K, decreases the thermal fluctuations, increases the irreversibility magnetic field (B) and the upper critical field (B) in the temperature range from 4.2 K to 25 K, and reduces B and B above 25 K

    The phenology of winter rye in Poland: an analysis of long-term experimental data

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    The study of the phenology of crops, although quite popular, has limitations, mainly because of frequent changes to crop varieties and management practices. Here, we present data on the phenology and yield of winter rye in western Poland collected between 1957 and 2012 from a long-term field experiment. Data were examined for trends through time and compared to climatological factors using regression analysis. Both annual air temperature and precipitation increased during the study period, equivalent to 2 °C and 186 mm, respectively, over the 52-year period for which met data were available. We detected significant delays in sowing date and recently in emergence, but significant advances were apparent in full flowering date equivalent to 4 days/decade. Yield and plant density experienced a step like change in 1986; yield increasing by ca. 70 % and plant density increasing by ca. 50 %, almost coinciding with a similar change in annual mean temperature, but most likely caused by a changed seed rate and use of herbicides. Future climate change is expected to have a greater impact on this crop, but farmers may be able to adapt to these changes by modifying water regimes, using new machinery and sowing new rye varieties

    In-depth studies of ground- and excited-state properties of Re(I) carbonyl complexes bearing 2,2′:6′,2′′-terpyridine and 2,6-bis(pyrazin-2-yl)pyridine coupled with π‑conjugated aryl chromophores

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    In the current work, comprehensive photophysical and electrochemical studies were performed for eight rhenium(I) complexes incorporating 2,2′:6′,2″-terpyridine (terpy) and 2,6-bis(pyrazin-2-yl)pyridine (dppy) with appended 1-naphthyl-, 2-naphthyl-, 9-phenanthrenyl, and 1-pyrenyl groups. Naphthyl and phenanthrenyl substituents marginally affected the energy of the MLCT absorption and emission bands, signaling a weak electronic coupling of the appended aryl group with the Re(I) center. The triplet MLCT state in these complexes is so low lying relative to the triplet 3ILaryl that the thermal population of the triplet excited state delocalized on the organic chromophore is ineffective. The attachment of the electron-rich pyrenyl group resulted in a noticeable red shift and a significant increase in molar absorption coefficients of the lowest energy absorption of the resulting Re(I) complexes due to the contribution of intraligand charge-transfer (ILCT) transitions occurring from the pyrenyl substituent to the terpy/dppy core. At 77 K, the excited states of [ReCl(CO)3(Ln-κ2N)] with 1-pyrenyl-functionalized ligands were found to have predominant 3ILpyrene/3ILCTpyrene→terpy character. The 3IL/3ILCT nature of the lowest energy excited state of [ReCl(CO)3(4′-(1-pyrenyl)-terpy-κ2N)] was also evidenced by nanosecond transient absorption and time-resolved emission spectroscopy. Enhanced room-temperature emission lifetimes of the complexes [ReCl(CO)3(Ln-κ2N)] with 1-pyrenyl-substituted ligands are indicative of the thermal activation between 3MLCT and 3IL/3ILCT excited states. Deactivation pathways occurring upon light excitation in [ReCl(CO)3(4′-(1-naphthyl)-terpy-κ2N)] and [ReCl(CO)3(4′-(1-pyrenyl)-terpy-κ2N)] were determined by femtosecond transient absorption studies
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