75 research outputs found

    Gametophytic phase of Doryopteris triphylla (Pteridaceae, Polypodiopsida)

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    Gametophytes of the Pteridaceae are moderately well known but there is still a quite large set of species to describe. Among these is Doryopteris triphylla, a member of the cheilanthoid clade (subgroup hemionitids). The main objective of this work is to describe the gametophyte of D. triphylla. In vitro cultures were prepared with spores coming from various sporophytes of different locations. In vivo observations were done periodically to monitor developmental critical events and reproductive activity. Germination followed the Vittaria pattern and the developmental processes adjusted to the Adiantum type. Adult cordate gametophytes produced normal sexual organs in unisexual prothalli. Doryopteris triphylla gametophytes exhibited somewhat peculiar features: the apical cell divided longitudinally, the first meristematic cell was rectangular, and archegoniate prothalli appeared much before than antheridiate ones

    Atlas de la flora alóctona de Madrid, I. Monilophyta-Gymnospermae

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    En este artículo se incluye la primera parte del atlas de flora alóctona de la Comunidad de Madrid, que incluye los taxones de helechos y gimnospermas. Únicamente se han considerado taxones que crecen fuera de zonas urbanas, parques y jardines, tanto introducidos como naturalizados. En total se han analizado 49 taxones, 2 de helechos y 47 de gimnospermas (33 Pinaceae y 14 Cupressaceae). De ellos, se han considerado 34 taxones (1 Salviniaceae, 22 Pinaceae, 11 Cupressaceae) incluyendo mapas de distribución, mientras que en otros 15 su presencia es dudosa en la actualidad o están únicamente localizadas en zonas urbanas. Dominan las especies de Pinaceae como resultado de las plantaciones forestales realizadas. Buena parte de las especies consideradas tienen capacidad para naturalizarse (se tiene constancia en 19 de ellas), pero por lo general su capacidad de expansión es limitada, no siendo invasoras; únicamente Azolla filiculoides Lam. tiene un comportamiento invasor, aunque su distribución en Madrid parece estable

    AgSn[Bi1−xSbx]Se3: Synthesis, Structural Characterization, and Electrical Behavior

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    Herein, we report the synthesis, characterization, and electrical properties of lead-free AgSnm[Bi1−xSbx]Se2+m (m = 1, 2) selenides. Powder X-ray diffraction patterns and Rietveld refinement data revealed that these selenides consisted of phases related to NaCl-type crystal structure. The microstructures and morphologies of the selenides were investigated by backscattered scanning electron microscopy, energy-dispersive X-ray spectroscopy, and high-resolution transmission electron microscopy. The studied AgSnm[Bi1−xSbx]Se2+m systems exhibited typical p-type semiconductor behavior with a carrier concentration of approximately ~+1020 cm−3. The electrical conductivity of AgSnm[Bi1−xSbx]Se2+m decreased from ~3.0 to ~10−3 S·cm−1 at room temperature (RT) with an increase in m from 1 to 2, and the Seebeck coefficient increased almost linearly with increasing temperature. Furthermore, the Seebeck coefficient of AgSn[Bi1−xSbx]Se3 increased from ~+36 to +50 μV·K−1 with increasing Sb content (x) at RT, while its average value determined for AgSn2[Bi1−xSbx]Se4 was approximately ~+4.5 μV·K−1.Depto. de Química InorgánicaFac. de Ciencias QuímicasTRUEpu

    Desarrollando tus talentos: gestión colaborativa de un programa de tutorías pares.

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    En el contexto del Programa de Acceso Inclusivo, Equidad y Permanencia de la Universidad de Santiago de Chile, se describen las acciones coordinadas de su área de Permanencia y Titulación Oportuna, basada en un sistema de tutorías pares, y los principales resultados de los últimos dos años de trabajo. Además, se describen las distintas interacciones entre los componentes del área como un conjunto de acciones coordinadas en consonancia con una política de acceso que valora el alto rendimiento escolar en contexto, mostrando cómo sus formas de trabajo han avanzado progresivamente hacia la colaboración. Finalmente se enuncian los principales aprendizajes y desafíos que el área enfrenta en la actualidad. El objetivo de este trabajo es dar a conocer las distintas etapas de implementación de un programa de tutorías pares en una universidad, de manera de compartir antecedentes de buenas prácticas en cuanto a procesos de nivelación en educación superior

    Nuevas localidades de tres helechos para la Península Ibérica

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    En este trabajo se incluyen novedades de interés corológico sobre tres helechos que son desconocidos o escasos en la Península Ibérica. En primer lugar, se testimonia por primera vez la presencia de Polystichum braunii en la Península Ibérica. Por otro lado, se aporta la tercera localidad conocida del híbrido Asplenium × aran-tohanum. Por último, se extiende notablemente hacia el interior peninsular la distribución conocida de Struthiopteris spicant var. homophyllum

    Ataxia por intoxicación crónica con fenitoina

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    El objetivo de este trabajo es describir un caso de ataxia adquirida del adulto por intoxicación crónica por fenitoína. Presentamos el caso de una paciente de 20 años de edad que consultó al servicio de Neurología en el año 2012, por cuadro de trastornos de la marcha y en la emisión de la palabra de 18 meses de evolución progresiva.Facultad de Ciencias Médica

    High Resolution Esophageal Manometry in Patients with Chagas Disease : A Cross-Sectional Evaluation

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    Gastrointestinal involvement affects 30-40% of the patients with chronic Chagas disease. Esophageal symptoms appear once the structural damage is established. Little is known about the usefulness of high resolution manometry to early identification of esophageal involvement. We performed a cross-sectional study at the Vall d'Hebron University Hospital (Barcelona, Spain) between May 2011 and April 2012. Consecutive patients diagnosed with Chagas disease in the chronic phase were offered to participate. All patients underwent a structured questionnaire about digestive symptoms, a barium esophagogram (Rezende classification) and an esophageal high resolution manometry (HRM). A control group of patients with heartburn who underwent an esophageal HRM in our hospital was selected. 62 out of 73 patients that were included in the study fulfilled the study protocol. The median age of the Chagas disease group (CG) was 37 (IQR 32-45) years, and 42 (67.7%) patients were female. Twenty-seven (43.5%) patients had esophageal symptoms, heartburn being the most frequent. Esophagogram was abnormal in 5 (8.77%). The esophageal HRM in the CG showed a pathological motility pattern in 14 patients (22.6%). All of them had minor disorders of the peristalsis (13 with ineffective esophageal motility and 1 with fragmented peristalsis). Hypotonic lower esophageal sphincter was found more frequently in the CG than in the control group (21% vs 3.3%; p<0.01). Upper esophageal sphincter was hypertonic in 22 (35.5%) and hypotonic in 1 patient. When comparing specific manometric parameters or patterns in the CG according to the presence of symptoms or esophagogram no statistically significant association were seen, except for distal latency. The esophageal involvement measured by HRM in patients with chronic Chagas disease in our cohort is 22.6%. All the patients with esophageal alterations had minor disorders of the peristalsis. Symptoms and esophagogram results did not correlate with the HRM results. Chagas disease is a parasitic disease mainly transmitted to humans by blood-sucking insects. The disease was endemic in Latin America, but it is now a global disease due to migratory movements. The disease can affect the heart and the digestive system (mainly esophagus and colon). Classically, esophageal assessment in Chagas disease is performed by X-ray and self-reported symptoms. However, they lack accuracy and detect only advanced stage of the disease. Recently, new tools, such as esophageal high resolution manometry, provide more detailed information about the motility disorders of the esophagus. We assessed the esophageal involvement in patients with Chagas disease by means of high resolution manometry and compared the findings with the X-ray and self-reported symptoms. We found a low rate of mild severity motility disorders. We did not find an association between X-ray assessment and symptoms with the high resolution manometry findings. The assessment of esophageal involvement in patients with Chagas disease may benefit from early diagnosis by high resolution manometry, although more research is needed

    Altered striatal endocannabinoid signaling in a transgenic mouse model of spinocerebellar ataxia type-3

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    Spinocerebellar ataxia type-3 (SCA-3) is the most prevalent autosomal dominant inherited ataxia. We recently found that the endocannabinoid system is altered in the post-mortem cerebellum of SCA-3 patients, and similar results were also found in the cerebellar and brainstem nuclei of a SCA-3 transgenic mouse model. Given that the neuropathology of SCA-3 is not restricted to these two brain regions but rather, it is also evident in other structures (e.g., the basal ganglia), we studied the possible changes to endocannabinoid signaling in the striatum of these transgenic mice. SCA-3 mutant mice suffer defects in motor coordination, balance and they have an abnormal gait, reflecting a cerebellar/brainstem neuropathology. However, they also show dystonia-like behavior (limb clasping) that may be related to the malfunction/deterioration of specific neurons in the striatum. Indeed, we found a loss of striatal projecting neurons in SCA-3 mutant mice, accompanied by a reduction in glial glutamate transporters that could potentially aggravate excitotoxic damage. In terms of endocannabinoid signaling, no changes in CB2 receptors were evident, yet an important reduction in CB1 receptors was detected by qPCR and immunostaining. The reduction in CB1 receptors was presumed to occur in striatal afferent and efferent neurons, also potentially aggravating excitotoxicity. We also measured the endocannabinoid lipids in the striatum and despite a marked increase in the FAAH enzyme in this area, no overall changes in these lipids were found. Collectively, these studies confirm that the striatal endocannabinoid system is altered in SCA-3 mutant mice, adding to the equivalent changes found in other strongly affected CNS structures in this type of ataxia (i.e.: the cerebellum and brainstem). These data open the way to search for drugs that might correct these changes.Funding: This study has been supported: (i) by MICINN (SAF2009-11847 and SAF2015-68580-C2-1-R), CIBERNED (CB06/05/0089) and “Fundación Eugenio Rodríguez Pascual”, to JFR; (ii) by the Research and Education Component of the Advancing a Healthier Wisconsin Endowment at the Medical College of Wisconsin, to CJH; and (iii) by Fundação para a Ciência e Tecnologia through the project POCI-01-0145-FEDER-016818 (PTDC/NEU-NMC/3648/2014) and co-financed by the Portuguese North Regional Operational Program (ON.2 – O Novo Norte) under the National Strategic Reference Framework (QREN), through the European Regional Development Fund (FEDER), to PM. Carmen Rodríguez-Cueto was a predoctoral fellow supported by FPI Program-Ministry of Science. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.info:eu-repo/semantics/publishedVersio

    Albiglutide and cardiovascular outcomes in patients with type 2 diabetes and cardiovascular disease (Harmony Outcomes): a double-blind, randomised placebo-controlled trial

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    Background: Glucagon-like peptide 1 receptor agonists differ in chemical structure, duration of action, and in their effects on clinical outcomes. The cardiovascular effects of once-weekly albiglutide in type 2 diabetes are unknown. We aimed to determine the safety and efficacy of albiglutide in preventing cardiovascular death, myocardial infarction, or stroke. Methods: We did a double-blind, randomised, placebo-controlled trial in 610 sites across 28 countries. We randomly assigned patients aged 40 years and older with type 2 diabetes and cardiovascular disease (at a 1:1 ratio) to groups that either received a subcutaneous injection of albiglutide (30–50 mg, based on glycaemic response and tolerability) or of a matched volume of placebo once a week, in addition to their standard care. Investigators used an interactive voice or web response system to obtain treatment assignment, and patients and all study investigators were masked to their treatment allocation. We hypothesised that albiglutide would be non-inferior to placebo for the primary outcome of the first occurrence of cardiovascular death, myocardial infarction, or stroke, which was assessed in the intention-to-treat population. If non-inferiority was confirmed by an upper limit of the 95% CI for a hazard ratio of less than 1·30, closed testing for superiority was prespecified. This study is registered with ClinicalTrials.gov, number NCT02465515. Findings: Patients were screened between July 1, 2015, and Nov 24, 2016. 10 793 patients were screened and 9463 participants were enrolled and randomly assigned to groups: 4731 patients were assigned to receive albiglutide and 4732 patients to receive placebo. On Nov 8, 2017, it was determined that 611 primary endpoints and a median follow-up of at least 1·5 years had accrued, and participants returned for a final visit and discontinuation from study treatment; the last patient visit was on March 12, 2018. These 9463 patients, the intention-to-treat population, were evaluated for a median duration of 1·6 years and were assessed for the primary outcome. The primary composite outcome occurred in 338 (7%) of 4731 patients at an incidence rate of 4·6 events per 100 person-years in the albiglutide group and in 428 (9%) of 4732 patients at an incidence rate of 5·9 events per 100 person-years in the placebo group (hazard ratio 0·78, 95% CI 0·68–0·90), which indicated that albiglutide was superior to placebo (p&lt;0·0001 for non-inferiority; p=0·0006 for superiority). The incidence of acute pancreatitis (ten patients in the albiglutide group and seven patients in the placebo group), pancreatic cancer (six patients in the albiglutide group and five patients in the placebo group), medullary thyroid carcinoma (zero patients in both groups), and other serious adverse events did not differ between the two groups. There were three (&lt;1%) deaths in the placebo group that were assessed by investigators, who were masked to study drug assignment, to be treatment-related and two (&lt;1%) deaths in the albiglutide group. Interpretation: In patients with type 2 diabetes and cardiovascular disease, albiglutide was superior to placebo with respect to major adverse cardiovascular events. Evidence-based glucagon-like peptide 1 receptor agonists should therefore be considered as part of a comprehensive strategy to reduce the risk of cardiovascular events in patients with type 2 diabetes. Funding: GlaxoSmithKline
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