Low-temperature rotational relaxation of CO in self-collisions and in-collisions with Ne and He

The low-temperature rotational relaxation of CO in self-collisions and in collisions with the rare-gas atoms Ne and He has been investigated in supersonic expansions with a combination of resonance-enhanced multiphoton ionization (REMPI) spectroscopy and time-of-flight techniques. For the REMPI detection of CO, a novel 2 + 1′ scheme has been employed through the A1 state of CO. From the measured data, average cross sections for rotational relaxation have been derived as a function of temperature in the range 5-100 K. For CO-Ne and CO-He, the relaxation cross sections grow, respectively, from values of ∼20 and 7 Å2 at 100 K to values of ∼65-70 and ∼20 A°2 in the 5-20 K temperature range. The cross section for the relaxation of CO-CO grows from a value close to 40 Å2 at 100 K to a maximum of 60 Å2 at 20 K and then decreases again to 40 Å2 at 5 K. These results are qualitatively similar to those obtained previously with the same technique for N2-N 2, N2-Ne, and N2-He collisions, although in the low-temperature range (T < 20 K) the CO relaxation cross sections are significantly larger than those for N2. Some discrepancies have been found between the present relaxation cross sections for CO-CO and CO-He and the values derived from electron-induced fluorescence experiments. © 2005 American Chemical Society.Financial support through the Ramón y Cajal program. Financial support from the EU Research Training Network “Reaction Dynamics”, Grant HPRNCT-1999-00007.Financial support from the Spanish Ministry of Education through the State Secretary of Education and University. Support from the Plan Andaluz de Investigación (Group FQM-205). Funding by the MEC of Spain under Grants FIS2004-00456 and BQU2002-04627-C02-02Peer Reviewe

Activation of aromatic C−C bonds of 2,2’-bipyridine ligands

4,4’-Disubstituted-2,2′-bipyridine ligands coordinated to Mo and Re cationic fragments become dearomatized by an intramolecular nucleophilic attack from a deprotonated N-alkylimidazole ligand in cis disposition. The subsequent protonation of these neutral complexes takes place on a pyridine carbon atom rather than at nitrogen, weakening an aromatic C−C bond and affording a dihydropyridyl moiety. Computational calculations allowed for the rationalization of the formation of the experimentally obtained products over other plausible alternatives.Financialsupport from Ministerio de Economía y Competitividad/FEDER (grant CTQ2015-70231-P) and Principado de Asturias (grant GRUPIN14-103) is gratefully acknowledged. J.D.thanks COMPUTAEX for granting access to LUSITANIA supercomputing facilities.Peer Reviewe

Uso de los antisépticos en atención primaria

ResumenLas heridas se pueden clasificar, según el mecanismo de acción, en quirúrgicas o traumáticas (que pueden ser incisas, como las provocadas por un objeto cortante; contusas, causadas por un objeto romo; punzantes, provocadas por objetos afilados y largos; por desgarro, causadas por tracción de los tejidos; por mordedura, que tienen alto riesgo de infección, por lo que no se deben suturar) o, por la evolución del proceso de cicatrización, en agudas o crónicas (úlceras por presión, úlceras vasculares, úlceras neuropáticas, heridas agudas con tórpida evolución). El empleo de antisépticos en cualquiera de los casos suele estar limitado a la limpieza y cuidados iniciales (48–72h) y al lavado de manos e instrumental, y su uso en heridas crónicas o cronificadas es más discutible. En el caso de quemaduras sucede lo mismo, y es más recomendable el empleo de formulaciones que favorezcan la hidratación.En población pediátrica se suele recomendar el empleo de antisépticos con un perfil de seguridad conocido y baja absorción, especialmente en el caso del cuidado del cordón umbilical, donde la evidencia recomienda el empleo de gluconato de clorhexidina.Otro uso de los antisépticos es el cuidado de heridas producidas por la implantación de objetos dentro de la estética corporal (piercing y similares), siendo recomendable el empleo de antisépticos transparentes que permitan observar la evolución de la técnica.AbstractWounds can be classified according to their mechanism of action into surgical or traumatic (which may be incision wounds, such as those provoked by a sharp object; contusions, caused by a blunt force; puncture wounds, caused by long, sharp objects; lacerations, caused by tears to the tissue; or bites, which have a high risk of infection and consequently should not be sutured). Wounds can also be classified by their healing process into acute or chronic (pressure ulcers, vascular ulcers, neuropathic ulcers, acute wounds with torpid clinical course). The use of antiseptics in any of these wounds is usually limited to cleaning and initial care —up to 48 hours— and to washing of hands and instruments. The use of antiseptics in chronic or persistent wounds is more debatable. The same is true of burns, in which the use of formulations that encourage hydration is recommended.In the pediatric population, the use of antiseptics with a known safety profile and low absorption is usually recommended, especially in the care of the umbilical cord, in which evidence supports the use of chlorhexidine gluconate.Another use of antiseptics is the care of wounds produced by procedures used in body esthetics, such as piercings; in these procedures, it is advisable to use transparent antiseptics that allow visualization of the technique

A Novel Role For Nanog As An Early Cancer Risk Marker In Patients With Laryngeal Precancerous Lesions

NANOG is a master regulator of embryonic stem cell pluripotency, found to be frequently aberrantly expressed in a variety of cancers, including laryngeal carcinomas. This study investigates for the first time the role of NANOG expression in early stages of laryngeal tumourigenesis and its potential utility as cancer risk marker. NANOG protein expression was evaluated by immunohistochemistry using two large independent cohorts of patients with laryngeal precancerous lesions, and correlated with clinicopathological parameters and laryngeal cancer risk. NANOG expression was detected by immunohistochemistry in 49 (60%) of 82 laryngeal dysplasias, whereas expression was negligible in patient-matched normal epithelia. Strong NANOG expression was found in 22 (27%) lesions and was established as cut-off point, showing the most robust association with laryngeal cancer risk (P = 0.003) superior to the histological classification (P = 0.320) the current gold standard in the clinical practice. Similar trends were obtained using a multicenter validation cohort of 86 patients with laryngeal dysplasia. Our findings uncover a novel role for NANOG expression in laryngeal tumourigenesis, and its unprecedented application as biomarker for cancer risk assessment

Adolescent cannabinoid pre-exposure effects on cocaine self administration, food reinforced behavior and cerebral glucose metabolism adult rats

[Poster] 11th EBPS Biennal Meeting, 2005, September 9-12, Barcelona, Spain. Poster Session B: 4. Addiction and Dependence IIPublicad

Evolución paleoambiental de la mitad sur de la Península Ibérica. Aplicación a la evaluación del comportamiento de los repositorios de residuos radiactivos

Esta publicación refleja los resultados obtenidos de la realización de los proyectos "EQUIP: Evidency from Quaternary Infills Palaeohydrogeology" (F 14W/ CT96/0031), financiado por la UE, "Evolución Paleoclimática de [a Mitad Sur de [a Península Ibérica" financiado por ENRESA y "Paleoclima" financiado por el Consejo de Seguridad Nuclear y ENRESA. La cuenca de Guadix-Baza, sector oriental, es una de las escasas zonas europeas donde se ha conservado un registro razonablemente completo del Pleistoceno. La cuenca de Guadix Baza, en régimen continental desde el Plioceno, funcionó bajo un régimen centrípeto, con abanicos aluviales en los bordes y una zona compleja lacustre en mosaico en su centro. Se ha podido establecer la existencia de una amplia variedad de facies aluviales y fluviales y sus interrelaciones. La sedimentación en el margen lacustre estaba constituida por arenas bioclásticas y lutitas con fósiles, mientras que en zonas más centrales predominaron lutitas yesíferas, lutitas con yeso intrasedimentario, arenas yesíferas yesos y, ocasionalmente, carbonatos que durante un período concreto depositaron los materiales que configuran el "Nivel Calcáreo de Orce", calizas y dolomías con cantidades variables de yeso y terrígenos cerca de los bordes. El trabajo de campo permitió el establecimiento de una serie estratigráfica tipo compuesta, que refleja los principales acontecimiento paleoambientales que tuvieron lugar durante el Pleistoceno. Con el fin de evitar la yesificación de la calcita y aragonito, propia del ambiente lacustre, la serie tipo de ha establecido en el registro del margen lacustre. Con ayuda del análisis paleomagnético y el análisis de la racemización de aminoácidos en conchas de moluscos y ostrácodos se ha establecido la cronología numérica de la sección estratigráfica tipo que cubre desde el límite Plioceno-Pleistoceno hasta unos 250 ka BP, cuando la erosión de la cabecera del río Fardes alcanza la cuenca abriéndola hacia el valle del Guadalquivir y cesando [a sedimentación lacustre. También se ha datado un depósito de terraza fluvial. Se han obtenido datos paleoambientales "instantáneos" mediante el estudio palinológico, el análisis paleobotánico de material silicificado (madera opalizada) o carbonizado (análisis paleoantracológico), el análisis geoquímico orgánico de algunos niveles especialmente favorables. La geoquímica orgánica de biomarcadores de algunos niveles concretos proporcionó datos sobre su origen (plantas terrestres o acuáticas) y confirmó que un conspicuo nivel carbonoso tuvo su origen en un incendio forestal. El análisis paleobiológico basado en la distribución de especies de ostrácodos, gasterópodos y pelecípodos ha permitido una primera aproximación paleoambiental, pese al evidente sesgo introducido por la presencia de fuentes salinas y materiales yesíferos en el área fuente de los abanicos aluviales del límite oriental de la cuenca. Esta interpretación se ha depurado mediante el estudio geoquímico inorgánico, isótopos estables y elementos traza de las conchas calcíticas de ostrácodos. Ello ha permitido el establecimiento de una alternancia de períodos "fríos y húmedos" y "cálidos y áridos" que permiten reconocer de las clases climáticas "mediterráneo seco" y "mediterráneo húmedo" sensu Horowitz (1989), que tienen sus correlatos en el registro paleoclimático de los grandes lagos del rift del Mar Muerto, el Mar Caspio y lagos pluviales de Norte América. La correlación de los datos isotópicos con las paleosalinidades deducidas del estudio de las inclusiones fluidas en yeso intrasedimentario ha permitido corroborar estas interpretaciones. Esto plantea un nuevo enfoque en el análisis del comportamiento de los repositorios de residuos radiactivos de alta

Evidence that breast cancer risk at the 2q35 locus is mediated through IGFBP5 regulation.

GWAS have identified a breast cancer susceptibility locus on 2q35. Here we report the fine mapping of this locus using data from 101,943 subjects from 50 case-control studies. We genotype 276 SNPs using the 'iCOGS' genotyping array and impute genotypes for a further 1,284 using 1000 Genomes Project data. All but two, strongly correlated SNPs (rs4442975 G/T and rs6721996 G/A) are excluded as candidate causal variants at odds against &gt;100:1. The best functional candidate, rs4442975, is associated with oestrogen receptor positive (ER+) disease with an odds ratio (OR) in Europeans of 0.85 (95% confidence interval=0.84-0.87; P=1.7 × 10(-43)) per t-allele. This SNP flanks a transcriptional enhancer that physically interacts with the promoter of IGFBP5 (encoding insulin-like growth factor-binding protein 5) and displays allele-specific gene expression, FOXA1 binding and chromatin looping. Evidence suggests that the g-allele confers increased breast cancer susceptibility through relative downregulation of IGFBP5, a gene with known roles in breast cell biology

Enhanced Stability and Bioactivity of Natural Anticancer Topoisomerase I Inhibitors through Cyclodextrin Complexation

The use of cyclodextrins as drug nano-carrier systems for drug delivery is gaining importance in the pharmaceutical industry due to the interesting pharmacokinetic properties of the resulting inclusion complexes. In the present work, complexes of the anti-cancer alkaloids camptothecin and luotonin A have been prepared with β-cyclodextrin and hydroxypropyl-β-cyclodextrin. These cyclodextrin complexes were characterized by nuclear magnetic resonance spectroscopy (NMR). The variations in the 1H-NMR and 13C-NMR chemical shifts allowed to establish the inclusion modes of the compounds into the cyclodextrin cavities, which were supported by docking and molecular dynamics studies. The efficiency of the complexation was quantified by UV-Vis spectrophotometry and spectrofluorimetry, which showed that the protonation equilibria of camptothecin and luotonin A were drastically hampered upon formation of the inclusion complexes. The stabilization of camptothecin towards hydrolysis inside the cyclodextrin cavity was verified by the quantitation of the active lactone form by reverse phase liquid chromatography fluorimetric detection, both in basic conditions and in the presence of serum albumin. The antitumor activity of luotonin A and camptothecin complexes were studied in several cancer cell lines (breast, lung, hepatic carcinoma, ovarian carcinoma and human neuroblastoma) and an enhanced activity was found compared to the free alkaloids, particularly in the case of hydroxypropyl-β-cyclodextrin derivatives. This result shows that the cyclodextrin inclusion strategy has much potential towards reaching the goal of employing luotonin A or its analogues as stable analogues of camptothecin

Molecular physiology of nickel and cobalt homeostasis in Rhizobium leguminosarum.

Transition metals such as Fe, Cu, Mn, Ni, or Co are essential nutrients, as they are constitutive elements of a significant fraction of cell proteins. Such metals are present in the active site of many enzymes, and also participate as structural elements in different proteins. From a chemical point of view, metals have a defined order of affinity for binding, designated as the Irving-Williams series (Irving and Williams, 1948) Mg2+ menor que Mn2+ menor que Fe2+ menor que Co2+ menor que Ni2+ menor que Cu2+mayor queZn2+ Since cells contain a high number of different proteins harbouring different metal ions, a simplistic model in which proteins are synthesized and metals imported into a ?cytoplasmic soup? cannot explain the final product that we find in the cell. Instead we need to envisage a complex model in which specific ligands are present in definite amounts to leave the right amounts of available metals and protein binding sites, so specific pairs can bind appropriately. A critical control on the amount of ligands and metal present is exerted through specific metal-responsive regulators able to induce the synthesis of the right amount of ligands (essentially metal binding proteins), import and efflux proteins. These systems are adapted to establish the metal-protein equilibria compatible with the formation of the right metalloprotein complexes. Understanding this complex network of interactions is central to the understanding of metal metabolism for the synthesis of metalloenzymes, a key topic in the Rhizobium-legume symbiosis. In the case of the Rhizobium leguminosarum bv viciae (Rlv) UPM791 -Pisum sativum symbiotic system, the concentration of nickel in the plant nutrient solution is a limiting factor for hydrogenase expression, and provision of high amounts of this element to the plant nutrient solution is required to ensure optimal levels of enzyme synthesis (Brito et al., 1994)