On the heterochromatic number of hypergraphs associated to geometric graphs and to matroids

The heterochromatic number hc(H) of a non-empty hypergraph H is the smallest integer k such that for every colouring of the vertices of H with exactly k colours, there is a hyperedge of H all of whose vertices have different colours. We denote by nu(H) the number of vertices of H and by tau(H) the size of the smallest set containing at least two vertices of each hyperedge of H. For a complete geometric graph G with n > 2 vertices let H = H(G) be the hypergraph whose vertices are the edges of G and whose hyperedges are the edge sets of plane spanning trees of G. We prove that if G has at most one interior vertex, then hc(H) = nu(H) - tau(H) + 2. We also show that hc(H) = nu(H) - tau(H) + 2 whenever H is a hypergraph with vertex set and hyperedge set given by the ground set and the bases of a matroid, respectively

Light driven water oxidation by a single site cobalt salophen catalyst

A salophen cobalt(II) complex enables water oxidation at neutral pH in photoactivated sacrificial cycles under visible light, thus confirming the high appeal of earth abundant single site catalysis for artificial photosynthesis

Hole Hopping through Tryptophan in Cytochrome P450

Electron-transfer kinetics have been measured in four conjugates of cytochrome P450 with surface-bound Ru-photosensitizers. The conjugates are constructed with enzymes from Bacillus megaterium (CYP102A1) and Sulfolobus acidocaldarius (CYP119). A W96 residue lies in the path between Ru and the heme in CYP102A1, whereas H76 is present at the analogous location in CYP119. Two additional conjugates have been prepared with (CYP102A1)W96H and (CYP119)H76W mutant enzymes. Heme oxidation by photochemically generated Ru^(3+) leads to P450 compound II formation when a tryptophan residue is in the path between Ru and the heme; no heme oxidation is observed when histidine occupies this position. The data indicate that heme oxidation proceeds via two-step tunneling through a tryptophan radical intermediate. In contrast, heme reduction by photochemically generated Ru+ proceeds in a single electron tunneling step with closely similar rate constants for all four conjugates

Estudio detallado de los efectos del acetato de hidrocortisona durante la gestación sobre el número de fetos y abortos en la rata

The evolution of the effect of the administration of hydrocortisone acetate (HA) (4mg/100g weightlday) to the pregnant rat on the number of viable and nonviable fetuses was studied on days 6, 9, 12, 14, 16, 18 and 21 of gestation. The administration of HA to pregnant rats reduced the number of live fetuses starting on day 17 of treatment representing a loss of approximately 25% of the fetuses when they are compared with the control rats. High doses of cortisone acetate were seen to increase the percentage of rats whose uterus contained dead fetuses at any given period of study. On day 14 more over the entire litter was found to have died in utero in 22,2% of all cortisol injected rats, a finding which never occurred in controls. The effects of cortisol were most in evidence on day 21, when all fetuses were viable in controls as opposed to hormone-treated rats, 66% of which were found to contain nonviable fetuses.Se estudia la evolución del efecto de la administración de acetato de hidrocortisona (4mg/100 g. peso/día) a ratas sobre el número de fetos y abortos de la camada en los días 6, 9, 12, 14, 16, 18 y 21 de gestación. Se observa que el acetato de hidrocortisona disminuye el número de fetos vivos a partir del día 17 de tratamiento siendo la disminución más acusada en el día 21, en el que la diferencia respecto al grupo control es de un 25%. El acetato de hidrocortisona incrementa el porcentaje de ratas que presentan abortos en cualquiera de los periodos estudiados. Además en el día 14 el 22,2% de ratas inyectadas con acetato de hidrocortisona presentan abortos de la totalidad de sus fetos, hecho que nunca sucede en las ratas control. En el día 21 es más acusado el efecto de la hormona ya que mientras que las ratas testigo mantienen todos los fetos vivos, un 66% de ratas tratadas con cortisona siguen presentando abortos

Cambios en las proteínas plasmáticas totales de madres y crías por efecto del cortisol

Se estudia en ratas la influencia de la gestación y el cortisol sobre el contenido en proteínas plasmáticas totales de madres y crías. Se observa que la gestación no modifica el nivel de proteínas plasmáticas, mientras que el cortisol incrementa significativamente dicho parámetro tanto en ratas no gestantes como en las gestantes y en sus crías.We study in rats the influence of the gestation and the cortisol in the complet tContained in plasma proteins of mothers and newsborn. We observe that the gestation don't change the level of plasma proteins while the cortisol augment this parameter equal in no gestants rats as in gestants and in their newsborn

Estudio detallado de los efectos del acetato de hidrocortisona durante la gestación sobre el número de fetos y abortos en la rata

Se estudia la evolución del efecto de la administración de acetato de hidrocortisona (4mg/100 g. peso/día) a ratas sobre el número de fetos y abortos de la camada en los días 6, 9, 12, 14, 16, 18 y 21 de gestación. Se observa que el acetato de hidrocortisona disminuye el número de fetos vivos a partir del día 17 de tratamiento siendo la disminución más acusada en el día 21, en el que la diferencia respecto al grupo control es de un 25%. El acetato de hidrocortisona incrementa el porcentaje de ratas que presentan abortos en cualquiera de los periodos estudiados. Además en el día 14 el 22,2% de ratas inyectadas con acetato de hidrocortisona presentan abortos de la totalidad de sus fetos, hecho que nunca sucede en las ratas control. En el día 21 es más acusado el efecto de la hormona ya que mientras que las ratas testigo mantienen todos los fetos vivos, un 66% de ratas tratadas con cortisona siguen presentando abortos.The evolution of the effect of the administration of hydrocortisone aceta te (HA) (4mg/l00g weightlday) to the pregnant rat on the number of viable and nonviable fetuses was studied on days 6, 9, 12, 14, 16, 18 and 21 of gesta tion . . The administration of HA to pregnant rats reduced the number of live fe tuses starting on day 17 of treatment representing a loss of approximately 25% of the fetuses when they are compared with the control rats. High doses of cortisone acetate were seen to increase the percentage of rats whose uterus contained dead fetuses at any given period of study. On day 14 more over the entire litter was found to have died in utero in 22,2% of all cortisol injected rats, a finding which never occurred in controls. The effects of cortisol were most in evidence on day 21, when all fetuses were viable in controls as opposed to hormone-treated rats, 66% of which were found to contain nonviable fetuses

Biomarkers to improve functional outcome prediction after ischemic stroke:Results from the SICFAIL, STRAWINSKI, and PREDICT studies

BACKGROUND AND AIMS: Acute ischemic stroke (AIS) outcome prognostication remains challenging despite available prognostic models. We investigated whether a biomarker panel improves the predictive performance of established prognostic scores.METHODS: We investigated the improvement in discrimination, calibration, and overall performance by adding five biomarkers (procalcitonin, copeptin, cortisol, mid-regional pro-atrial natriuretic peptide (MR-proANP), and N-terminal pro-B-type natriuretic peptide (NT-proBNP)) to the Acute Stroke Registry and Analysis of Lausanne (ASTRAL) and age/NIHSS scores using data from two prospective cohort studies (SICFAIL, PREDICT) and one clinical trial (STRAWINSKI). Poor outcome was defined as mRS &gt; 2 at 12 (SICFAIL, derivation dataset) or 3 months (PREDICT/STRAWINSKI, pooled external validation dataset).RESULTS: Among 412 SICFAIL participants (median age 70 years, quartiles 59-78; 63% male; median NIHSS score 3, quartiles 1-5), 29% had a poor outcome. Area under the curve of the ASTRAL and age/NIHSS were 0.76 (95% CI 0.71-0.81) and 0.77 (95% CI 0.73-0.82), respectively. Copeptin (0.79, 95% CI 0.74-0.84), NT-proBNP (0.80, 95% CI 0.76-0.84), and MR-proANP (0.79, 95% CI 0.75-0.84) significantly improved ASTRAL score's discrimination, calibration, and overall performance. Copeptin improved age/NIHSS model's discrimination, copeptin, MR-proANP, and NT-proBNP improved its calibration and overall performance. In the validation dataset (450 patients, median age 73 years, quartiles 66-81; 54% men; median NIHSS score 8, quartiles 3-14), copeptin was independently associated with various definitions of poor outcome and also mortality. Copeptin did not increase model's discrimination but it did improve calibration and overall model performance.DISCUSSION: Copeptin, NT-proBNP, and MR-proANP improved modest but consistently the predictive performance of established prognostic scores in patients with mild AIS. Copeptin was most consistently associated with poor outcome in patients with moderate to severe AIS, although its added prognostic value was less obvious.</p