135 research outputs found
Wave packet dynamics in triplet states of Na2 attached to helium nanodroplets
The dynamics of vibrational wave packets excited in Na2 dimers in the triplet
ground and excited states is investigated by means of helium nanodroplet
isolation (HENDI) combined with femtosecond pump-probe spectroscopy. Different
pathways in the employed resonant multi-photon ionization scheme are
identified. Within the precision of the method, the wave packet dynamics
appears to be unperturbed by the helium droplet environment
Desorption Dynamics of Heavy Alkali Metal Atoms (Rb, Cs) off the Surface of Helium Nanodroplets
We present a combined ion imaging and density functional theory study of the
dynamics of the desorption process of rubidium and cesium atoms off the surface
of helium nanodroplets upon excitation of the perturbed and states,
respectively. Both experimental and theoretical results are well represented by
the pseudodiatomic model for effective masses of the helium droplet in the
desorption reaction of m_eff/m_He~10 (Rb) and 13 (Cs). Deviations from this
model are found for Rb excited to the 6p state. Photoelectron spectra indicate
that the dopant-droplet interaction induces relaxation into low-lying
electronic states of the desorbed atoms in the course of the ejection process.Comment: in press, J. Phys. Chem. A (2014
An immune response in the bumblebee, Bombus terrestris leads to increased food consumption
BACKGROUND: The concept of a costly immune system that must be traded off against other important physiological systems is fundamental to the burgeoning field of ecological immunity. Bumblebees have become one of the central models in this field. Although previous work has demonstrated costs of immunity in numerous life history traits, estimates of the more direct costs of bumblebee immunity have yet to be made. RESULTS: Here we show a 7.5% increase in energy consumption in response to non-pathogenic immune stimulation. CONCLUSION: This increase in energy consumption along with other results suggests that immunity is one of the most important physiological systems, with other systems being sacrificed for its continuing efficiency. This increased consumption and maintained activity contrasts with the sickness-induced anorexia and reduced activity found in vertebrates
Las necesidades proteicas de pacientes en estado crítico que reciben nutrición parenteral
Assess whether the current protein intake recommendations may improve the biochemical parameters of critical patients receiving parenteral nutrition. Methods: longitudinal study with three evaluations made (during the first 72 hours, on the 7th and the 14th days of PN). The following tests were applied: albumin, C-reactive protein, prealbumin, total cholesterol, HDL, triglycerides, lymphocytes, and glutathione peroxidase. The severity was determined by SOFA. The statistical analysis included the Spearman and Mann-Whitney tests, as well as ANOVA (analysis of variance). Results: among the 53 patients evaluated, 20 (37.74%) died. The mean calorie was 24.68 ± 9.78 kcal/kg (beginning of PN), 26.49 ± 8.89 kcal/kg (3rd to 7th days of PN), and 30.9 ± 12.19 kcal/kg (7th to 14th days of PN). The mean protein was 1.19 ± 0.44 g/kcal/kg (first 72 hours of PN), 1.29 ± 0.44 g/kcal/kg (3rd to 7th days of PN) and 1.49 ± 0.69 g/kcal/kg (7th to 14th days of PN). Prealbumin, albumin, total cholesterol and HDL were below the reference values, while the CRP levels were high. Throughout the three evaluation times, there was no a significant improvement on the levels of laboratory examinations. A strong and negative correlation was found between SOFA and prealbumin (r = -0.64, p = 0.05). Conclusions: the protein offer, according to the traditional recommendations, was not enough to improve the biochemical parameters of critical patients undergoing parenteral nutrition321250255COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESSem informaçãoEvaluar si las recomendaciones de ingesta de proteínas actuales pueden mejorar los parámetros bioquímicos de los pacientes críticos que reciben nutrición parenteral. Métodos: estudio longitudinal con tres evaluaciones realizadas (durante las primeras 72 horas, en el séptimo y los días decimocuarto de nutrición parenteral). Se aplicaron las siguientes pruebas: albúmina, proteína C reac ti va, prealbúmina, colesterol total, HDL, triglicéridos, linfocitos y glutatión peroxidasa. La gravedad se determinó por SOFA. El análisis estadístico incluyó las pruebas de Spearman y Mann-Whitney, así como ANOVA (análisis de varianza). Resultados: de los 53 pacientes evaluados, 20 (37,74%) fallecieron. La caloría media fue de 24,68 ± 9,78 kcal/kg (comienzo de PN), 26,49 ± 8,89 kcal/kg (tercero-séptimo días de PN), y 30,9 ± 12,19 kcal/kg (séptimo-décimo cuarto días de PN). La proteína media fue de 1,19 ± 0,44 g/ kcal/kg (primeras 72 horas de PN), 1,29 ± 0,44 g/kcal/kg (tercero-séptimo días de PN) y 1,49 ± 0,69 g/kcal/kg (séptimo- decimocuarto días de PN). La prealbúmina, la albúmina, el colesterol total y la HDL estaban por debajo de los valores de referencia, mientras que los niveles de PCR eran altos. A lo largo de los tres tiempos de evaluación, no hay una mejora significativa en los niveles de los exámenes de laboratorio. Una correlación fuerte y negativa entre SOFA y prealbúmina (r = -0,64, p = 0,05). Conclusiones: la oferta de proteínas, de acuerdo con las recomendaciones tradicionales, no fue suficiente para mejorar los parámetros bioquímicos de los pacientes críticos sometidos a nutrición parentera
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