904 research outputs found
A 560 yr summer temperature reconstruction for the Western Mediterranean basin based on stable carbon isotopes from <i>Pinus nigra</i> ssp. <i>laricio</i> (Corsica/France)
The Mediterranean is considered as an area which will be affected strongly by current climate change. However, temperature records for the past centuries which can contribute to a better understanding of future climate changes are still sparse for this region. Carbon isotope chronologies from tree-rings often mirror temperature history but their application as climate proxies is difficult due to the influence of the anthropogenic change in atmospheric CO<sub>2</sub> on the carbon isotope fractionation during photosynthetic CO<sub>2</sub> uptake. We tested the influence of different correction models accounting for plant response to increased atmospheric CO<sub>2</sub> on four annually resolved long-term carbon isotope records (between 400 and 800 yr) derived from Corsican pine trees (<i>Pinus nigra</i> ssp. <i>laricio</i>) growing at ecologically varying mountain sites on the island of Corsica. The different correction factors have only a minor influence on the main climate signals and resulting temperature reconstructions. Carbon isotope series show strong correlations with summer temperature and precipitation. A summer temperature reconstruction (1448–2007 AD) reveals that the Little Ice Age was characterised by low, but not extremely low temperatures on Corsica. Temperatures have been to modern temperatures at around 1500 AD. The reconstruction reveals warm summers during 1480–1520 and 1950–2007 AD and cool summers during 1580–1620 and 1820–1890 AD
A prospective randomized comparison of two instruments for dissection and vessel sealing in laparoscopic colorectal surgery
Background: A newly available, laparoscopic 5-mm bipolar vessel sealing device promises substantial advantages over the 10-mm instrument. This study compared the safety as well as the technical and surgical aspects of these different tools. Methods: For this study, 30 consecutive patients undergoing laparoscopic left-sided colectomy were prospectively randomized for the 5-mm LigaSure or The 10-mm LigaSure. The patients' demographics were analyzed together with their intraoperative and postoperative parameters, and the instruments were assessed by the surgeons with a standardized questionnaire. Results: The two groups were comparable and demonstrated similar mean operation times, blood losses, and hospital stays. The 5-mm LigaSure was applied in more operation steps and resulted in fewer bleeding episodes and less lens cleaning. Monopolar scissors were used less frequently in the 5-mm group, thus minimizing cauteric lesions and their complications (0 in the 5-mm group vs 2 in the 10-mm group). Overall satisfaction with the 5-mm LigaSure was significantly higher (8.4±0.18 vs 6.9±0.41 out of 10; p=0.002), with significant advantages in terms of dissection capacity, visibility, and handling. Conclusion: The 5-mm LigaSure is as secure and fast as the larger 10-mm device and compares favorably in terms of finer dissection as well as trocar flexibility and handling. Therefore, it can be used safely in laparoscopic colorectal surger
Proton and cadmium adsorption by the archaeon Thermococcus zilligii: Generalising the contrast between thermophiles and mesophiles as sorbents
Adsorption by microorganisms can play a significant role in the fate and transport of metals in natural systems. Surface complexation models (SCMs) have been applied extensively to describe metal adsorption by mesophilic bacteria, and several recent studies have extended this framework to thermophilic bacteria. We conduct acid-base titrations and batch experiments to characterise proton and Cd adsorption onto the thermophilic archaeon Thermococcus zilligii. The experimental data and the derived SCMs indicate that the archaeon displays significantly lower overall sorption site density compared to previously studied thermophilic bacteria such Anoxybacillus flavithermus, Geobacillus stearothermophilus, G. thermocatenulatus, and Thermus thermophilus. The thermophilic bacteria and archaea display lower sorption site densities than the mesophilic microorganisms that have been studied to date, which points to a general pattern of total concentration of cell wall adsorption sites per unit biomass being inversely correlated to growth temperature
CO21 234. Implantación trans apical de válvula aórtica: excelentes resultados en pacientes de alto riesgo
ObjetivosLa implantación transapical de válvulas aórticas es un método nuevo aplicable a pacientes de alto riesgo y estenosis grave de válvula aórtica. Un informe de nuestra experiencia inicial.MétodosDesde abril de 2008 fueron tratados 208 pacientes (edad 79±8 anos, media 36-99 años), con el método híbrido de implantación transapical de válvula aórtica. La media logística EuroSCORE (STS) fue de 40±20% (6-97%) y la media del STS score 21±16% (3-97%). Catorce pacientes ingresaron en shock cardiogénico. Operaciones combinadas fueron efectuadas en 30 pacientes. Intervención de coronarias con stent en 25 pacientes, corrección de ASD en un paciente, dilatación de estenosis pulmonar en un paciente. Aneurismectomía en dos pacientes.Implantación de stent en la arteria renal en un paciente.ResultadosEl éxito técnico de las operaciones fue del 99,5%, la mortalidad hospitalaria fue de 5,7% para todo el grupo, 21% para el grupo en shock cardiogénico. No hubo complicaciones neurológicas en ningún paciente. En el 6% de los pacientes operados hubo la necesidad de implantación de marcapasos. El análisis de regresión univariante demuestra que el shock cardiogénico, elevado B-type natriuretic peptide (BNP)-level, son claros indicadores para la mortalidad postoperatoria temprana (30 días después de la operación). Shock cardiogénico, New York Heart Association (NYHA) IV, altos scores de riesgo, insuficiencia renal grave, son factores independientes para la predicción de la mortalidad acumulativa.ConclusionesLa técnica de recambio transapical de válvulas aórticas reduce significativamente el riesgo operatorio en pacientes de alto riesgo en comparación con el método convencional de recambio valvular aórtico
Stereoscopic depth increases intersubject correlations of brain networks
Three-dimensionalmovies presented via stereoscopic displays have becomemore popular in recent years aiming at a more engaging viewing experience. However, neurocognitive processes associated with the perception of stereoscopic depth in complex and dynamic visual stimuli remain understudied. Here, we investigate the influence of stereoscopic depth on both neurophysiology and subjective experience. Using multivariate statistical learning methods, we compare the brain activity of subjects when freely watching the same movies in 2D and in 3D. Subjective reports indicate that 3D movies are more strongly experienced than 2D movies. On the neural level, we observe significantly higher intersubject correlations of cortical networks when subjects are watching 3D movies relative to the same movies in 2D. We demonstrate that increases in intersubject correlations of brain networks can serve as neurophysiologicalmarker for stereoscopic depth and for the strength of the viewing experience
Heart failure reversal by ventricular unloading in patients with chronic cardiomyopathy: criteria for weaning from ventricular assist devices
Simulating local deformations in the human cortex due to blood flow-induced changes in mechanical tissue properties: Impact on functional magnetic resonance imaging
Investigating human brain tissue is challenging due to the complexity and the manifold interactions between structures across different scales. Increasing evidence suggests that brain function and microstructural features including biomechanical features are related. More importantly, the relationship between tissue mechanics and its influence on brain imaging results remains poorly understood. As an important example, the study of the brain tissue response to blood flow could have important theoretical and experimental consequences for functional magnetic resonance imaging (fMRI) at high spatial resolutions. Computational simulations, using realistic mechanical models can predict and characterize the brain tissue behavior and give us insights into the consequent potential biases or limitations of in vivo, high-resolution fMRI. In this manuscript, we used a two dimensional biomechanical simulation of an exemplary human gyrus to investigate the relationship between mechanical tissue properties and the respective changes induced by focal blood flow changes. The model is based on the changes in the brain’s stiffness and volume due to the vasodilation evoked by neural activity. Modeling an exemplary gyrus from a brain atlas we assessed the influence of different potential mechanisms: (i) a local increase in tissue stiffness (at the level of a single anatomical layer), (ii) an increase in local volume, and (iii) a combination of both effects. Our simulation results showed considerable tissue displacement because of these temporary changes in mechanical properties. We found that the local volume increase causes more deformation and consequently higher displacement of the gyrus. These displacements introduced considerable artifacts in our simulated fMRI measurements. Our results underline the necessity to consider and characterize the tissue displacement which could be responsible for fMRI artifacts
Integrated transcriptome and proteome analyses reveal organ-specific proteome deterioration in old rats
Aging is associated with the decline of protein, cell, and organ function. Here, we use an integrated approach to characterize gene expression, bulk translation, and cell biology in the brains and livers of young and old rats. We identify 468 differences in protein abundance between young and old animals. The majority are a consequence of altered translation output, that is, the combined effect of changes in transcript abundance and translation efficiency. In addition, we identify 130 proteins whose overall abundance remains unchanged but whose sub-cellular localization, phosphorylation state, or splice-form varies. While some protein-level differences appear to be a generic property of the rats’ chronological age, the majority are specific to one organ. These may be a consequence of the organ’s physiology or the chronological age of the cells within the tissue. Taken together, our study provides an initial view of the proteome at the molecular, sub-cellular, and organ level in young and old rats
Free radicals induced lipid peroxidation following reperfusion in infants cardiac surgery: relationship to the release of the brain marker protein S-100 into the serum
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