Thermal Stability of Self-Assembled Monolayers of n-Hexanethiol on Au(111)-(1 × 1) and Au(001)-(1 × 1)

Thermal desorption in an ultrahigh vacuum of n-hexanethiol (C6T) self-assembled monolayers (SAMs) prepared from ethanolic solutions on Au(111) and Au(001) unreconstructed surfaces was investigated by X-ray photoelectron spectroscopy. The SAMs desorption was performed from room temperature (RT) to 380 K. We report that the hexanethiolate surface saturation coverage is bigger (∼0.4 ML) for the SAM on Au(001) than on Au(111) (∼0.33 ML). We identified a greater stability for C6T SAMs on Au(001). Large amounts of physisorbed species were found on preferred oriented (111) polycrystalline Au at the low coverage regime at RT, while the SAM on the Au(001) single crystal at this conditions desorbs at a steady pace. At 340 K, both SAMs remain stable at the coverage expected for the lying-down phases that maximizes the van der Waals interactions. We observe that at higher temperatures the carbon alpha-sulfur bond breaks, producing free S on both gold surfaces.Fil: Cristina, Lucila Josefina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Física del Litoral. Universidad Nacional del Litoral. Instituto de Física del Litoral; ArgentinaFil: Ruano Sandoval, Gustavo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Física del Litoral. Universidad Nacional del Litoral. Instituto de Física del Litoral; ArgentinaFil: Salvarezza, Roberto Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; ArgentinaFil: Ferron, Julio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Física del Litoral. Universidad Nacional del Litoral. Instituto de Física del Litoral; Argentina. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Departamento de Materiales; Argentin

Morphometric Discriminant Analysis of isolated chondrichthyan scales for palaeoecological inferences: the Middle Triassic of the Iberian Chain (Spain) as a case of study

Palaeontological studies on exosqueletal disarticulated remains of chondrichthyans have focused on teeth and only less interest has been paid to scales due their limited taxonomic and systematic significance. However, classical works linking the morphology and the function of the squamation in extant sharks suggest that, despite their limited taxonomic value, the study of isolated scales can be a useful tool for palaeoenvironmental and palaeoecological inferences. Following this idea, we have analyzed the fossil record of shark scales from two Middle Triassic sections of the Iberian Chain (Spain), identifying different functional types by means of a morphometric discriminant analysis. From a total of 1136 isolated chondrichthyan scales, 25% were identified as abrasion resistant scales, 62% as drag reduction scales and 13% as scales of generalized functions. The elevated proportion of abrasion resistant scales suggests that this chondrichthyan palaeocommunity was highly dominated by benthic sharks that lived over a hard sea floor. However, one of the stratigraphical levels studied (He-20), presents statistically significant differences from the others, showing a lower percentage of abrasion resistant scales and a larger percentage of drag reduction scales. This level can be linked with storm episodes that could introduce remains of bentho-pelagic or pelagic forms in the inner platform.. Finally, partial correlation analysis between relative abundances of functional scale types and tooth-based taxa from the same sections provide positive correlation between teeth of Hybodus and Pseudodalatias and drag reduction scales, and teeth of Prolatodon and abrasion strength scales.Los estudios paleontológicos de restos desarticulados de condrictios se han centrado en los dientes, no prestando prácticamente interésal estudio de sus escamas debido a su limitada importancia taxonómica y sistemática. Sin embargo, algunos trabajos clásicos que hanrelacionado su morfología y función en base al estudio de la escamación de tiburones actuales, sugieren que, a pesar de su limitado valortaxonómico, el estudio de las escamas aisladas puede ser una herramienta útil para obtener inferencias paleoambientales y paleoecológicas.Siguiendo estas ideas, se ha analizado el registro fósil de escamas de tiburón de dos secciones del Triásico Medio de la Cordillera Ibérica(España), identificando diferentes tipos funcionales por medio de un análisis morfométrico discriminante. De un total de 1.136 escamasaisladas de condrictios, el 25% de ellas fueron identificadas como escamas resistentes a la abrasión, el 62% como de reducción de la friccióncon el agua y el 13% de las escamas como de función generalizada. La elevada proporción de las escamas resistentes a la abrasión sugiereque esta paleocomunidad de condrictios estaba claramente dominada por tiburones bentónicos que habitaban sobre un sustrato rocoso. Sinembargo, uno de los niveles estratigráficos estudiados (He-20), presenta diferencias estadísticamente significativas con los demás, mostrandoun porcentaje más bajo de escamas resistentes a la abrasión y un porcentaje mayor de las escamas de reducción de la fricción con elagua. Este nivel se relaciona con episodios de tormenta que pudieron haber introducido los restos de formas bento-pelágicas o pelágicasen la plataforma interna. Por último, el análisis de correlación parcial entre la abundancia relativa de los tipos funcionales de escamas ytaxones en basado dientes de las mismas secciones proporcionan una correlación positiva entre los dientes de Hybodus y Pseudodalatias yescamas de reducción de la fricción con el agua, y dientes de Prolatodon y escamas resistencia a la abrasión

Impurity Effects in Two-Electron Coupled Quantum Dots: Entanglement Modulation

We present a detailed analysis of the electronic and optical properties of two-electron quantum dots with a two-dimensional Gaussian confinement potential. We study the effects of Coulomb impurities and the possibility of manipulate the entanglement of the electrons by controlling the confinement potential parameters. The degree of entanglement becomes highly modulated by both the location and charge screening of the impurity atom, resulting two regimes: one of low entanglement and other of high entanglement, with both of them mainly determined by the magnitude of the charge. It is shown that the magnitude of the oscillator strength of the system could provide an indication of the presence and characteristics of impurities that could largely influence the degree of entanglement of the system.Comment: Regular Article (Journal of Physics B, in press), 9 pages, 10 figure

Microarray profiling of mononuclear peripheral blood cells identifies novle candidate genes related to chemoradiation response in rectal cancer

Preoperative chemoradiation significantly improves oncological outcome in locally advanced rectal cancer. However there is no effective method of predicting tumor response to chemoradiation in these patients. Peripheral blood mononuclear cells have emerged recently as pathology markers of cancer and other diseases, making possible their use as therapy predictors. Furthermore, the importance of the immune response in radiosensivity of solid organs led us to hypothesized that microarray gene expression profiling of peripheral blood mononuclear cells could identify patients with response to chemoradiation in rectal cancer. Thirty five 35 patients with locally advanced rectal cancer were recruited initially to perform the study. Peripheral blood samples were obtained before neaodjuvant treatment. RNA was extracted and purified to obtain cDNA and cRNA for hybridization of microarrays included in Human WG CodeLink bioarrays. Quantitative real time PCR was used to validate microarray experiment data. Results were correlated with pathological response, according to Mandard´s criteria and final UICC Stage (patients with tumor regression grade 1–2 and downstaging being defined as responders and patients with grade 3–5 and no downstaging as non-responders). Twenty seven out of 35 patients were finally included in the study. We performed a multiple t-test using Significance Analysis of Microarrays, to find those genes differing significantly in expression, between responders (n = 11) and non-responders (n = 16) to CRT. The differently expressed genes were: BC 035656.1, CIR, PRDM2, CAPG, FALZ, HLA-DPB2, NUPL2, and ZFP36. The measurement of FALZ (p = 0.029) gene expression level determined by qRT-PCR, showed statistically significant differences between the two groups. Gene expression profiling reveals novel genes in peripheral blood samples of mononuclear cells that could predict responders and non-responders to chemoradiation in patients with locally advanced rectal cancer. Moreover, our investigation added further evidence to the importance of mononuclear cells’ mediated response in the neoadjuvant treatment of rectal cancer.This investigation was supported by the Fundación Investigación Biomédica Mutua Madrileña. MC, CC and AB were supported by projects P08-TIC-4299 and CTS2200 of Junta de Andalucía, TIN2009-13489 of DGICT, Madrid, and GREIB PYR_2010-02 and 2010_05 of University of Granada

Telomere Shortening Impairs Regeneration of the Olfactory Epithelium in Response to Injury but Not Under Homeostatic Conditions

Atrophy of the olfactory epithelium (OE) associated with impaired olfaction and dry nose represents one of the most common phenotypes of human aging. Impairment in regeneration of a functional olfactory epithelium can also occur in response to injury due to infection or nasal surgery. These complications occur more frequently in aged patients. Although age is the most unifying risk factor for atrophic changes and functional decline of the olfactory epithelium, little is known about molecular mechanisms that could influence maintenance and repair of the olfactory epithelium. Here, we analyzed the influence of telomere shortening (a basic mechanism of cellular aging) on homeostasis and regenerative reserve in response to chemical induced injury of the OE in late generation telomere knockout mice (G3 mTerc−/−) with short telomeres compared to wild type mice (mTerc+/+) with long telomeres. The study revealed no significant influence of telomere shortening on homeostatic maintenance of the OE during mouse aging. In contrast, the regenerative response to chemical induced injury of the OE was significantly impaired in G3 mTerc−/− mice compared to mTerc+/+ mice. Seven days after chemical induced damage, G3 mTerc−/− mice exhibited significantly enlarged areas of persisting atrophy compared to mTerc+/+ mice (p = 0.031). Telomere dysfunction was associated with impairments in cell proliferation in the regenerating epithelium. Deletion of the cell cycle inhibitor, Cdkn1a (p21) rescued defects in OE regeneration in telomere dysfunctional mice. Together, these data indicate that telomere shortening impairs the regenerative capacity of the OE by impairing cell cycle progression in a p21-dependent manner. These findings could be relevant for the impairment in OE function in elderly people

Postnatal loss of Dlk1 imprinting in stem cells and niche astrocytes regulates neurogenesis.

The gene for the atypical NOTCH ligand delta-like homologue 1 (Dlk1) encodes membrane-bound and secreted isoforms that function in several developmental processes in vitro and in vivo. Dlk1, a member of a cluster of imprinted genes, is expressed from the paternally inherited chromosome. Here we show that mice that are deficient in Dlk1 have defects in postnatal neurogenesis in the subventricular zone: a developmental continuum that results in depletion of mature neurons in the olfactory bulb. We show that DLK1 is secreted by niche astrocytes, whereas its membrane-bound isoform is present in neural stem cells (NSCs) and is required for the inductive effect of secreted DLK1 on self-renewal. Notably, we find that there is a requirement for Dlk1 to be expressed from both maternally and paternally inherited chromosomes. Selective absence of Dlk1 imprinting in both NSCs and niche astrocytes is associated with postnatal acquisition of DNA methylation at the germ-line-derived imprinting control region. The results emphasize molecular relationships between NSCs and the niche astrocyte cells of the microenvironment, identifying a signalling system encoded by a single gene that functions coordinately in both cell types. The modulation of genomic imprinting in a stem-cell environment adds a new level of epigenetic regulation to the establishment and maintenance of the niche, raising wider questions about the adaptability, function and evolution of imprinting in specific developmental contexts

Perspectives and Integration in SOLAS Science

Why a chapter on Perspectives and Integration in SOLAS Science in this book? SOLAS science by its nature deals with interactions that occur: across a wide spectrum of time and space scales, involve gases and particles, between the ocean and the atmosphere, across many disciplines including chemistry, biology, optics, physics, mathematics, computing, socio-economics and consequently interactions between many different scientists and across scientific generations. This chapter provides a guide through the remarkable diversity of cross-cutting approaches and tools in the gigantic puzzle of the SOLAS realm. Here we overview the existing prime components of atmospheric and oceanic observing systems, with the acquisition of ocean–atmosphere observables either from in situ or from satellites, the rich hierarchy of models to test our knowledge of Earth System functioning, and the tremendous efforts accomplished over the last decade within the COST Action 735 and SOLAS Integration project frameworks to understand, as best we can, the current physical and biogeochemical state of the atmosphere and ocean commons. A few SOLAS integrative studies illustrate the full meaning of interactions, paving the way for even tighter connections between thematic fields. Ultimately, SOLAS research will also develop with an enhanced consideration of societal demand while preserving fundamental research coherency. The exchange of energy, gases and particles across the air-sea interface is controlled by a variety of biological, chemical and physical processes that operate across broad spatial and temporal scales. These processes influence the composition, biogeochemical and chemical properties of both the oceanic and atmospheric boundary layers and ultimately shape the Earth system response to climate and environmental change, as detailed in the previous four chapters. In this cross-cutting chapter we present some of the SOLAS achievements over the last decade in terms of integration, upscaling observational information from process-oriented studies and expeditionary research with key tools such as remote sensing and modelling. Here we do not pretend to encompass the entire legacy of SOLAS efforts but rather offer a selective view of some of the major integrative SOLAS studies that combined available pieces of the immense jigsaw puzzle. These include, for instance, COST efforts to build up global climatologies of SOLAS relevant parameters such as dimethyl sulphide, interconnection between volcanic ash and ecosystem response in the eastern subarctic North Pacific, optimal strategy to derive basin-scale CO2 uptake with good precision, or significant reduction of the uncertainties in sea-salt aerosol source functions. Predicting the future trajectory of Earth’s climate and habitability is the main task ahead. Some possible routes for the SOLAS scientific community to reach this overarching goal conclude the chapter

A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)

Meeting abstrac

Experimental and computational investigations of electron dynamics in micro atmospheric pressure radio-frequency plasma jets operated in He/N2 mixtures

The electron power absorption dynamics in radio frequency driven micro atmospheric pressure capacitive plasma jets are studied based on experimental phase resolved optical emission spectroscopy and the computational particle in cell simulations with Monte Carlo treatment of collisions. The jet is operated at 13.56 MHz in He with different admixture concentrations of N2 and at several driving voltage amplitudes. We find the spatio-temporal dynamics of the light emission of the plasma at various wavelengths to be markedly different. This is understood by revealing the population dynamics of the upper levels of selected emission lines/bands based on comparisons between experimental and simulation results. The populations of these excited states are sensitive to different parts of the electron energy distribution function and to contributions from other excited states. Mode transitions of the electron power absorption dynamics from the Ω- to the Penning-mode are found to be induced by changing the N2 admixture concentration and the driving voltage amplitude. Our numerical simulations reveal details of this mode transition and provide novel insights into the operation details of the Penning-mode. The characteristic excitation/emission maximum at the time of maximum sheath voltage at each electrode is found to be based on two mechanisms: (i) a direct channel, i.e. excitation/emission caused by electrons generated by Penning ionization inside the sheaths and (ii) an indirect channel, i.e. secondary electrons emitted from the electrode due to the impact of positive ions generated by Penning ionization at the electrodes

Nurses' perceptions of aids and obstacles to the provision of optimal end of life care in ICU

Contains fulltext : 172380.pdf (publisher's version ) (Open Access