10,795 research outputs found
Hydrazones as Singular Reagents in Asymmetric Organocatalysis
This Minireview summarizes strategies and developments regarding the use of hydrazones as reagents in asymmetric organocatalysis, their distinct roles in nucleophile–electrophile, cycloaddition, and cyclization reactions. The key structural elements governing the reactivity of these reagents in a preferred pathway will be discussed, as well as their different interactions with organocatalysts, leading to diverse activation modes. Along these studies, the synthetic equivalence of N-monoalkyl, N,N-dialkyl, and N-acyl hydrazones with several synthons is also highlighted. Emphasis is also put on the mechanistic studies performed to understand the observed reactivities. Finally, the functional group transformations performed from the available products has also been analyzed, highlighting the synthetic value of these methodologies, which served to access numerous families of valuable multifunctional compounds and nitrogen-containing heterocycles.Ministerio de Economía y Competitividad CTQ2013-48164-C2-1-P, CTQ201348164-C2-2-PEuropean FEDER fundsJunta de Andalucía 2012/FQM 107
Endocardial-mesenchymal transition underlies fusion of the conotruncal ridges during embryonic cardiac outflow tract septation
The embryonic cardiac outflow tract (conotruncus) is a single tubular chamber that connects the right ventricle with the aortic arch arteries. It contains two opposite, long and helical mesenchymal cushions covered by endocardial cells (conotruncal ridges). Conotruncal division (septation) gives rise to the adult right and left outflows together with the aortic and pulmonary valves. It takes place by fusion of the two opposite ridges and formation of the conotruncal septum. Although the participation of neural crest cells in septation is well established, the mechanism of fusion of the conotruncal ridges remains unknown. Defects in fusion have been shown to produce bicuspid aortic valve, the most prevalent human congenital cardiac malformation, in a hamster model.
Three fusion mechanisms have been proposed to operate during embryonic development: epithelial adhesion, epithelial apoptosis and epithelial-mesenchymal transition (EMT). The first mechanism entails the expression of adhesion molecules and the maintenance of the identity of cells in contact, whereas in the other two, epithelial cells covering the fusing structures disappear by apoptosis or by transforming into mesenchymal cells. The objective of this study is to elucidate the mechanism involved in the fusion of the conotruncal ridges. Immunofluorecence techniques were used in ED 11-12 hamster embryos.
The results indicate that the mechanism of EMT, but not epithelial adhesion or apoptosis, is involved in the process of fusion of the conotruncal ridges. The EMT mechanism associated with conotruncal septation seems to be uncoupled from the process of formation of the endocardial cushions, which takes place at early stages. With these results, we can raise the hypothesis that defects in the EMT process may lead to different morphological types of bicuspid aortic valve.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. This study was supported by P10-CTS-6068 (Junta de Andalucía), CGL2014-52356-P and CGL2017-85090-P (Ministerio de Economía y Competitividad), contract UMAJI75 (Junta de Andalucía, European Social Fund), and Universidad de Málaga
Working Environment in Nursing: Needs Improvement?
Background: Knowing the quality of life of professionals is important because it is related to job performance, better results, and greater productivity, which results in better patient care. Objective: To know the Professional Quality of Life perceived by the nurses at the Geriatric Hospital of Toledo (Spain). Method: A descriptive cross-section study was employed to measure the Professional Quality of Life of all healthcare nurses (69 in total) at the Geriatric Hospital of Toledo. The questionnaire used as a measuring instrument was the Professional Quality of Life - 35. The data obtained was analyzed by means of: descriptive statistics, single-factor ANOVA variance analysis, T Student tests, and simple and multiple regression analysis. The study was approved by both the research commission and the ethics commission at the Hospital Complex of Toledo. Participation in the study on behalf of the nursing staff was voluntary. Results: In total, 45 responses were obtained (65.2%). The overall mean score measured the perceived Professional Quality of Life to be low. In relation to the three dimensions evaluated in the study, the highest average found was in “intrinsic motivation,” followed by “workload”, and then “management support.” In the multivariate analysis, “management support” was shown as the most influential factor in the Professional Quality of Life with a 23% influence (P<0.001), followed by workload with 9% (P = 0.01). Conclusions: The professionals at the participating center perceive their workplace as having an elevated degree of responsibility, a large quantity of work, a high occurrence of rushes and fatigue, and all this with little support on behalf of management. Promotions are scarce or the policies for receiving a promotion are inadequate. The perception of Professional Quality of Life in nursing is low. The obtained results indicate a need for an organizing cultural change based on participation, motivation, and increased management support
Organizadores Gráficos: los Mapas Mentales como herramienta para potenciar las habilidades de comprensión lectora
Reading comprehension in L2 is perhaps the skill whose
requirements have changed most and most rapidly due
to the demand of the information society. Readers not
only need to interpret words and sentences in articles
or books: sometimes they have to make a meaning out
of disconnected pieces of information in pouring messages
on websites, and social networks. The purpose of the
present study is to explore the possibilities of mind-mapping
techniques in order to foster the reading comprehension
abilities in students of English as L2 by working
under the assumption that the latter can be improved
when apparently loose pieces of written information are
connected by means of images and lines. The experiment
in the project involved a total of 84 participants of
two consecutive academic levels: first and second year
of post-compulsory secondary education. Different sessions
and two parallel procedures were scheduled in
order to provide us with contrasting data that could be
systematized numerically. Even though the sessions that
could be scheduled were limited in number, the analysis
of the data suggests some noticeable improvement in
the reading comprehension abilities in most participants
and some perception of progress in a majority of them.
Their positive feedback, suggests that sustained work in
this field could improve their reading comprehension
skills in a significant way.La comprensión lectora en L2 es quizás la habilidad cuyos
requisitos han cambiado más y más rápidamente
debido a la demanda de la sociedad de la información.
Los lectores no solo necesitan interpretar palabras y oraciones
en artículos o libros. A veces tienen que encontrar
un significado de piezas desconectadas de información
en el vertido de mensajes en sitios web y redes sociales.
El propósito de presente estudio es explorar las posibilidades
de los mapas mentales como técnicas de aprendizaje
para fomentar la comprensión lectora bajo la suposición
de que mejoran. Se analizan las habilidades de
comprensión en estudiantes de inglés como L2 cuando
se enfrentan con fragmentos aparentemente sueltos de
información escrita conectados por medio de imágenes
y líneas. La experiencia en el proyecto involucró a un total
de 84 participantes de dos niveles académicos consecutivos:
primero y segundo año de la educación secundaria
postobligatoria. Se programaron diferentes sesiones
y dos procedimientos paralelos para proporcionar datos
contrastantes que pudieran ser sistematizados numéricamente.
Aunque las sesiones que podrían programarse
eran limitados en número, el análisis de los datos sugiere
alguna mejora notable en las habilidades de comprensión
lectora en la mayoría de los participantes y cierta percepción
de progreso en la mayoría de ellos. La retroalimentación
positiva de este alumnado sugiere que el trabajo
sostenido en este campo podría mejorar las habilidades
de comprensión lectora de manera significativ
Trace elements and C and N isotope composition in two mushroom species from a mine-spill contaminated site
Fungi play a key role in the functioning of soil in terrestrial ecosystems, and in particular in the
remediation of degraded soils. The contribution of fungi to carbon and nutrient cycles, along with
their capability to mobilise soil trace elements, is well-known. However, the importance of life history
strategy for these functions has not yet been thoroughly studied. This study explored the soil-fungi
relationship of two wild edible fungi, the ectomycorrhizal Laccaria laccata and the saprotroph
Volvopluteus gloiocephalus. Fruiting bodies and surrounding soils in a mine-spill contaminated area
were analysed. Isotope analyses revealed Laccaria laccata fruiting bodies were 15N-enriched when
compared to Volvopluteus gloiocephalus, likely due to the transfer of 15N-depleted compounds to their
host plant. Moreover, Laccaria laccata fruiting bodies δ13C values were closer to host plant values than
surrounding soil, while Volvopluteus gloiocephalus matched the δ13C composition to that of the soil.
Fungal species presented high bioaccumulation and concentrations of Cd and Cu in their fruiting bodies.
Human consumption of these fruiting bodies may represent a toxicological risk due to their elevated Cd
concentrations
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