1,933 research outputs found
Outcomes in liver transplantation: does sex matter?
A growing literature has highlighted important differences in transplant-related outcomes between men and women. In the United States there are fewer women than men on the liver transplant waitlist and women are two times less likely to receive a deceased or living-related liver transplant. Sex-based differences exist not only in waitlist but also in post-transplant outcomes, particularly in some specific liver diseases, such as hepatitis C. In the era of individualized medicine, recognition of these differences in the approach to pre and post-liver transplant care may impact short and long-term outcomes
Synapse elimination activates a coordinated homeostatic presynaptic response in an autaptic circuit
The number of synapses present in a neuronal circuit is not fixed. Neurons must compensate for changes in connectivity caused by synaptic pruning, learning processes or pathological conditions through the constant adjustment of the baseline level of neurotransmission. Here, we show that cholinergic neurons grown in an autaptic circuit in the absence of glia sense the loss of half of their synaptic contacts triggered by exposure to peptide p4.2, a C-terminal fragment of SPARC. Synaptic elimination is driven by a reorganization of the periodic F-actin cytoskeleton present along neurites, and occurs without altering the density of postsynaptic receptors. Neurons recover baseline neurotransmission through a homeostatic presynaptic response that consists of the coordinated activation of rapid synapse formation and an overall potentiation of presynaptic calcium influx. These results demonstrate that neurons establishing autaptic connections continuously sense and adjust their synaptic output by tweaking the number of functional contacts and neurotransmitter release probability
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Geostatistical radar-raingauge combination with nonparametric correlograms: methodological considerations and application in Switzerland
Modelling spatial covariance is an essential part of all geostatistical methods. Traditionally, parametric semivariogram models are fit from available data. More recently, it has been suggested to use nonparametric correlograms obtained from spatially complete data fields. Here, both estimation techniques are compared. Nonparametric correlograms are shown to have a substantial negative bias. Nonetheless, when combined with the sample variance of the spatial field under consideration, they yield an estimate of the semivariogram that is unbiased for small lag distances. This justifies the use of this estimation technique in geostatistical applications.
Various formulations of geostatistical combination (Kriging) methods are used here for the construction of hourly precipitation grids for Switzerland based on data from a sparse realtime network of raingauges and from a spatially complete radar composite. Two variants of Ordinary Kriging (OK) are used to interpolate the sparse gauge observations. In both OK variants, the radar data are only used to determine the semivariogram model. One variant relies on a traditional parametric semivariogram estimate, whereas the other variant uses the nonparametric correlogram. The variants are tested for three cases and the impact of the semivariogram model on the Kriging prediction is illustrated. For the three test cases, the method using nonparametric correlograms performs equally well or better than the traditional method, and at the same time offers great practical advantages.
Furthermore, two variants of Kriging with external drift (KED) are tested, both of which use the radar data to estimate nonparametric correlograms, and as the external drift variable. The first KED variant has been used previously for geostatistical radar-raingauge merging in Catalonia (Spain). The second variant is newly proposed here and is an extension of the first. Both variants are evaluated for the three test cases as well as an extended evaluation period. It is found that both methods yield merged fields of better quality than the original radar field or fields obtained by OK of gauge data. The newly suggested KED formulation is shown to be beneficial, in particular in mountainous regions where the quality of the Swiss radar composite is comparatively low. An analysis of the Kriging variances shows that none of the methods tested here provides a satisfactory uncertainty estimate. A suitable variable transformation is expected to improve this
Distribution of polymorphisms IL4 -590 C/T and IL4 RP2 in the human populations of Madeira, Azores, Portugal, Cape
Abstract: The IL4 gene is located on chromosome 5q23.3-31.2. Polymorphisms within this cytokine gene, like the derivative allele T of IL4-590, have been reported as being associated to elevated IgE serum levels and asthma. In the present work, the allelic and genotypic frequency of the IL4-590 and IL4 RP2 polymorphisms was carried out in 599 individuals from Madeira, Azores, Portugal mainland, Cape Verde and Guinea-Bissau and in a sample of 101 asthmatics from Madeira population. In all populations the polymorphisms were in LD and presented a significant dissimilar allelic and genotypic distribution (p<0.05) except between mainland Portugal and Madeira when compared
to Azores. Significant differences regarding both loci were found between Madeira population and the group of asthmatics.
Genotype 183183TT frequency is higher for African populations while 253253CC prevails in Caucasian populations.
The existence of a Hardy-Weinberg Disequilibrium in Guinea-Bissau population not observed in neutral markers
leads to the hypothesis of natural selection occurring in these loci probably associated to a rapid population
growth an hypothesis strengthened by neutral STRs D5S818 and CSF1PO gene diversity.info:eu-repo/semantics/publishedVersio
Intrahepatic Cholestasis of Pregnancy: Risk Factor for Neonatal Respiratory Distress Syndrome?
Introdução: A colestase intra-hepática da gravidez está associada a complicações fetais e neonatais graves, incluindo síndrome de dificuldade respiratória. Tem sido recomendada terapêutica materna com ácido ursodesoxicólico e antecipação do parto para reduzir o risco de complicações. Os objetivos
foram determinar a associação entre colestase intra-hepática da gravidez e síndrome de dificuldade respiratória neonatal e avaliar a relação com níveis maternos de ácidos biliares e
procedimentos perinatais.
Metodologia: Estudo caso-controlo incluindo grávidas com colestase intra-hepática da gravidez e respetivos recém-nascidos (grupo colestase), com parto numa maternidade
portuguesa de nível III entre 2006 e 2010. Os controlos foram
emparelhados para idade gestacional e peso ao nascimento (1
caso para 2 controlos).
Resultados: Foram incluídas 42 grávidas com colestase
intra-hepática da gravidez (incidência 0,15%) e 53 recém-
-nascidos. Dez recém-nascidos do grupo colestase (19,2%) e 14 controlos (13,7%) tiveram dificuldade respiratória(p=0,375). A FiO2 máxima foi superior no grupo colestase
(mediana 34,0% vs. 25,0%; p=0,294), mas sem diferença
quanto à ventilação mecânica. A idade gestacional ao diagnóstico de colestase materna foi menor nos recém-nascidos com dificuldade respiratória (mediana 30,5 vs 33,5 semanas;
p=0,024). A taxa de parto desencadeado iatrogenicamente(69,8% vs. 40,6%; p=0,001; OR=3,4), cesariana (66,0% vs 44,3%; p=0,01; OR=2,4) e corticoterapia pré-natal (43,4% vs.
25,5%; p=0,022) foi significativamente maior no grupo colestase.
Não se encontrou relação entre dificuldade respiratória neonatal e níveis maternos de ácidos biliares nem terapêutica materna com ácido ursodesoxicólico. Conclusão: A colestase intra-hepática da gravidez, sobretudo
de início precoce, está tendencialmente associada a síndrome de dificuldade respiratória neonatal. A antecipação do parto
traz riscos adicionais para os recém-nascidos. A corticoterapia pré-natal neste contexto pode ter mascarado a verdadeira incidência de dificuldade respiratória neonatal
Bronchogenic cyst excision using a robotic laparoscopic transdiaphragmatic approach
AbstractWe describe one case of a bronchopulmonary foregut malformations (BPFM) excision using robotic technology in a pediatric patient. Traditionally, surgical resection is performed using a thoracotomy or video-assisted thoracic surgery. A 12-year-old girl with a previous medical history of cough was diagnosed with a left cystic paracardiac mass. Her operation employed a transdiaphragmatic approach to remove the mass. The postoperative course was uneventful, and she was discharged after four days. The subsequent pathology concluded that the mass was a bronchogenic cyst. To the best of our knowledge, this is the first report of transdiaphragmatic laparoscopic approach and first use of robotics-platform for BPFM excision by children. We elected to use this type of procedure to decrease the postoperative morbidity associated with the thoracic approach. The robotic technology permitted surgical resection with a similar efficiency as standard thoracic or laparoscopic procedures. We hypothesized that this technology would simplify some of the technical points, decreasing any postoperative complications
White-emitting organometallo-silica nanoparticles for sun-like light-emitting diodes
This work discloses a radically new way to prepare white-emitting hybrid nanoparticles, whose implementation in lighting devices provides encouraging proof-of-concept performances towards alternative sunlight sources. In detail, the new synthetic approach is based on the kinetic control of the formation of organometallic dots, built via the condensation of three emitting iridium(III) complexes, which are subsequently transformed into mesoporous silica nanoparticles. Our novel hybrid systems, which are exceptionally stable under harsh irradiation and thermal stress environments, show a bright white emission with a record photoluminescence quantum yield. Their remarkable performance prompted us to implement them into single-component hybrid light-emitting diodes (HLEDs), achieving a high-quality sunlight source that is stable for >2000 hours with linearly extrapolated stabilities of >10 000 h. This represents one of the most stable HLEDs reported so far, while the versatility of our synthesis approach with respect to the type of emitters opens new opportunities for the design and fabrication of white-emitting color down-converters for HLEDs in the future.C. E., E. L. and J. R. B acknowledge Spanish MINECO and AEI/FEDER (ref. CTQ2016-78463-P). C. E. also thanks Universidad de La Rioja for a grant. E. F. and R.D.C. acknowledge the program “Ayudas para la atracción de talento investigador – Modalidad 1 of the Consejería de Educación, Juventud y Deporte – Comunidad de Madrid with the reference number 2016-T1/IND-1463”. R. D. C. acknowledges Spanish MINECO for the Ramón y Cajal program (RYC-2016-20891). J.G.M. acknowledges Spanish MINECO and AEI/FEDER (ref. CTQ2014-60017-R). E.S. thanks Spanish MINECO and AEI/FEDER (ref. CTQ2015-74494-JIN) and the University of Alicante (“Ayudas para la captación de talento” program with the reference number UATALENTO16-03)
Magnetic zeolites: novel nanoreactors through radiofrequency heating
Many catalytic applications use conventional heating to increase the temperature to allow the desired reaction. A novel methodology is presented for the preparation of magnetic zeolite-based catalysts, allowing more efficient radiofrequency heating. These nanoreactors are tested in the isomerisation of citronellal with successful results and without any apparent deactivation
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