Dissociative photoionization of phenyl triflate, a photoacid generator for photolithography, at 92 eV.

The dissociative photoionization of phenyl triflate (C6H5OSO2CF3), a neutral photoacid generator used in photolithography, was investigated in a gas phase experiment employing extreme ultraviolet (EUV) synchrotron radiation at 92 eV and photoelectron-photoion coincidence detection. The interaction of EUV photons with the molecule leads almost exclusively to dissociation, which is dominated by a sequential fragmentation mechanism, in which SO2, CF3, CO, and C2H2 are lost. For lithographic purposes, the lack of the observation of a fragment that could serve as a precursor for the formation of triflic acid means that the effective photoacid generator concentration in a photoresist is reduced, impacting its patterning performance in EUV lithography. A better understanding of the dissociative photoionization of photoresist components and proxies thereof can provide a crucial handle that guides the design of photoresists for the upcoming technology nodes with ever decreasing feature sizes for more powerful computer chips.

Hafnium-an optical hydrogen sensor spanning six orders in pressure.

Hydrogen detection is essential for its implementation as an energy vector. So far, palladium is considered to be the most effective hydrogen sensing material. Here we show that palladium-capped hafnium thin films show a highly reproducible change in optical transmission in response to a hydrogen exposure ranging over six orders of magnitude in pressure. The optical signal is hysteresis-free within this range, which includes a transition between two structural phases. A temperature change results in a uniform shift of the optical signal. This, to our knowledge unique, feature facilitates the sensor calibration and suggests a constant hydrogenation enthalpy. In addition, it suggests an anomalously steep increase of the entropy with the hydrogen/metal ratio that cannot be explained on the basis of a classical solid solution model. The optical behaviour as a function of its hydrogen content makes hafnium well-suited for use as a hydrogen detection material.

Decúbito prono: revisión narrativa / Prone position: revision narrative

Los pacientes con síndrome de distrés respiratorio agudo demandan gran atención en la Unidad de Cuidados Intensivos. La utilización del decúbito prono en esta población tiene un sustento bibliográfico sumamente sólido y, en varios ensayos clínicos aleatorizados, se ha comprobado su efecto sobre la oxigenación medida a través de la relación PaO2/FiO2 e incluso su impacto en prolongar la supervivencia. Esta estrategia ha demostrado ser una maniobra útil y accesible para la mayor parte de las Unidades de Cuidados Intensivos y su implementación, realizada de manera protocolizada y por personal entrenado, debería ser considerada en un grupo selecto de pacientes quienes se beneficiarían en términos de mortalidad. En la Argentina, pareciera que muchos profesionales han decidido implementar la maniobra en sus lugares de trabajo, con un bajo porcentaje de complicaciones.(AU)

Patients with acute respiratory distress syndrome demand great attention in the Intensive Care Unit. The use of prone position in this population has a very robust literary support, and several randomized clinical trials have shown the effect on oxygenation (represented by an increase in PaO2/FiO2) and even its impact on increasing survival. The prone position has proved to be a useful and accessible maneuver for most of Intensive Care Units and its implementation, following a protocol and done for trained personnel, should be considered in a select group of patients who would benefit in terms of mortality. In Argentina, many professionals have decided to implement the prone position in their workplace, with a low percentage of complications.(AU)

Mortalidad en pacientes con síndrome de distress respiratorio / Mortality in patients with respiratory distress syndrome

INTRODUCCIÓN: La mortalidad del distress respiratorio agudo está disminuyendo, aunque hay poca evidencia sobre su pronóstico después del egreso hospitalario y la adecuada estratificación pronóstica con la nueva clasificación de Berlín. MÉTODOS: Se analizó retrospectivamente la mortalidad de pacientes con SDRA admitidos en la Unidad de Cuidados Críticos de1 Hospital Universitario de la ciudad de Buenos Aires, desde el 1 de 2008 hasta el 6 de 2011. Se definió SDRA por hipoxemia con PaO2/FiO2≤200 mmHg con al menos 10 cmH2O de PEEP y FiO2≥0,5 e infiltrados bilaterales en la radiografía de tórax en ausencia de edema agudo de pulmón cardiogénico en las primeras 72h de ventilación mecánica. Se registraron la mortalidad hospitalaria y a 6 meses, los factores asociados a mortalidad, la utilización de terapias de rescate, y la validez de la clasificación de Berlín para casos moderados y graves. RESULTADOS: Se incluyeron 98 pacientes; edad 59±19 años; 42,9% con comorbilidades mayores; APACHEII 22±7; SOFA (día 1) 8±3. La VM en posición prono se aplicó en 20,4% y en 12,2% rescates especiales (12 óxido nítrico y 1 ECMO). La mortalidad hospitalaria y a 6 meses fue de 37,7 y 43,8% respectivamente. Los factores asociados a mortalidad fueron: edad, shock séptico en las primeras 72 h, presión plateau (Ppl) >30cmH2O durante las primeras 72 h y la presencia de comorbilidades preexistentes. No hubo diferencia de mortalidad entre los grupos moderado y grave (41,2 vs. 36,8%; p = 0,25). CONCLUSIONES: En este estudio que incluyó pacientes con hipoxemia más grave y alto porcentaje con comorbilidades mayores, la mortalidad fue menor que en algunos estudios previos; no hubo incremento en la mortalidad después del egreso hospitalario. La clasificación de Berlín no diferenció el pronóstico entre los casos moderados y graves

INTRODUCTION: Mortality in Acute Respiratory Distress Syndrome (ARDS) is decreasing, although its prognosis after hospital discharge and the prognostic accuracy of Berlin's new ARDS stratification are uncertain. METHODS: We did a restrospective analysis of hospital and 6 month mortality of patients with ARDS admitted to the Intensive Care Unit of a Univeristy Hospital in Buenos Aires, between January 2008 and June 2011. ARDS was defined by PaO2/FiO2 lower than 200 mmHg under ventilation with at least 10 cm H2O of PEEP and a FiO2 higher or equal than 0.5. and the presence of bilateral infiltrates in chest radiography, in the absence of cardiogenic acute pulmonary edema, during the first 72 h of mechanical ventilation. Mortality associated risk factors, the use of rescue therapies and Berlin's stratification for moderate and severe ARDS patients were considered. RESULTS: Ninety eight patients were included; mean age was 59±19 years old, 42,9% had mayor co-morbidities; APACHE II at admission was 22±7; SOFA at day 1 was 8±3. Prone position ventilation was applied in 20,4% and rescue measures in 12,2% (12 patients with nitric oxide and 1 with extracorporeal membrane oxygenation). Hospital and 6 months mortality were 37.7 and 43.8% respectively. After logistic regression analysis, only age, the presence of septic shock at admission, Ppl >30 cmH2O, and major co-morbidities were independently associated with hospital outcome. There was no difference between moderate and severe groups (41,2 and 36,8% respectively; p = 0,25). CONCLUSION: In this cohort, including patients with severe hypoxemia and high percentage of mayor co-morbidities, ARDS associated mortality was lower than some previous studies. There was no increase in mortality after hospital discharge. There was no difference in mortality between moderate and severe groups according to Berlin's definition

Quasi-Particle Self-Consistent GW for Molecules.

We present the formalism and implementation of quasi-particle self-consistent GW (qsGW) and eigenvalue only quasi-particle self-consistent GW (evGW) adapted to standard quantum chemistry packages. Our implementation is benchmarked against high-level quantum chemistry computations (coupled-cluster theory) and experimental results using a representative set of molecules. Furthermore, we compare the qsGW approach for five molecules relevant for organic photovoltaics to self-consistent GW results (scGW) and analyze the effects of the self-consistency on the ground state density by comparing calculated dipole moments to their experimental values. We show that qsGW makes a significant improvement over conventional G0W0 and that partially self-consistent flavors (in particular evGW) can be excellent alternatives.

Mortality in patients with respiratory distress syndrome. / Mortalidad en pacientes con síndrome de distress respiratorio.

INTRODUCTION: Mortality in Acute Respiratory Distress Syndrome (ARDS) is decreasing, although its prognosis after hospital discharge and the prognostic accuracy of Berlin's new ARDS stratification are uncertain. METHODS: We did a restrospective analysis of hospital and 6 month mortality of patients with ARDS admitted to the Intensive Care Unit of a Univeristy Hospital in Buenos Aires, between January 2008 and June 2011. ARDS was defined by PaO2/FiO2 lower than 200 mmHg under ventilation with at least 10 cm H2O of PEEP and a FiO2 higher or equal than 0.5. and the presence of bilateral infiltrates in chest radiography, in the absence of cardiogenic acute pulmonary edema, during the first 72 hs of mechanical ventilation. Mortality associated risk factors, the use of rescue therapies and Berlin's stratification for moderate and severe ARDS patients were considered. RESULTS: Ninety eight patients were included; mean age was 59±19 years old, 42,9% had mayor co-morbidities; APACHE II at admission was 22±7; SOFA at day 1 was 8±3. Prone position ventilation was applied in 20,4% and rescue measures in 12,2% (12 patients with nitric oxide and 1 with extracorporeal membrane oxygenation). Hospital and 6 months mortality were 37.7 and 43.8% respectively. After logistic regression analysis, only age, the presence of septic shock at admission, Ppl >30 cmH2O, and major co-morbidities were independently associated with hospital outcome. There was no difference between moderate and severe groups (41,2 and 36,8% respectively; p=0,25). CONCLUSION: In this cohort, including patients with severe hypoxemia and high percentage of mayor co-morbidities, ARDS associated mortality was lower than some previous studies. There was no increase in mortality after hospital discharge. There was no difference in mortality between moderate and severe groups according to Berlin's definition.

Off-Diagonal Self-Energy Terms and Partially Self-Consistency in GW Calculations for Single Molecules: Efficient Implementation and Quantitative Effects on Ionization Potentials.

The GW method in its most widespread variant takes, as an input, Kohn-Sham (KS) single particle energies and single particle states and yields results for the single-particle excitation energies that are significantly improved over the bare KS estimates. Fundamental shortcomings of density functional theory (DFT) when applied to excitation energies as well as artifacts introduced by approximate exchange-correlation (XC) functionals are thus reduced. At its heart lies the quasi-particle (qp) equation, whose solution yields the corrected excitation energies and qp-wave functions. We propose an efficient approximation scheme to treat this equation based on second-order perturbation theory and self-consistent iteration schemes. We thus avoid solving (large) eigenvalue problems at the expense of a residual error that is comparable to the intrinsic uncertainty of the GW truncation scheme and is, in this sense, insignificant.

The GW-Method for Quantum Chemistry Applications: Theory and Implementation.

The GW-technology corrects the Kohn-Sham (KS) single particle energies and single particle states for artifacts of the exchange-correlation (XC) functional of the underlying density functional theory (DFT) calculation. We present the formalism and implementation of GW adapted for standard quantum chemistry packages. Our implementation is tested using a typical set of molecules. We find that already after the first iteration of the self-consistency cycle, G0W0, the deviations of quasi-particle energies from experimental ionization potentials and electron affinities can be reduced by an order of magnitude against those of KS-DFT using GGA or hybrid functionals. Also, we confirm that even on this level of approximation there is a considerably diminished dependency of the G0W0-results on the XC-functional of the underlying DFT.

Accuracy of weight and height estimation in an intensive care unit.

We report the findings from a prospective study determining the magnitude of errors in the visual estimation of weight and height of critically ill patients. Forty-two consecutive patients were weighed by a physician with a calibrated stretcher scale and length measured with a steel measuring tape. The predicted body weight was calculated using the ARDSnet formulae. Attending physicians and nurses were asked to estimate patient's actual weight, predicted weight and height. The average percent errors in estimation of actual and predicted weight were 11.4 and 14.6%, respectively. Errors greater than 20% in patient's actual and predicted weight were observed in 15 and 24% of cases, respectively. The majority of height estimations (86%) had an error < 10%. There were non-significant differences between the estimations made by intensive care unit physicians and nurses. Our study shows that estimations of patient's weight made by intensive care unit staff are often inaccurate. In contrast, estimations of height made by intensive care unit staff are usually adequate. Estimated body weight of critically ill patients has implications for drug and respiratory therapy and should be used with caution.

Endothelin-1 responsiveness of a 1.4 kb phospholamban promoter fragment in rat cardiomyocytes transfected by the gene gun.

The transcriptional regulation of an isolated rat phospholamban (PL) promoter fragment in rat cardiomyocytes was analyzed by applying a new method to reach substantially higher transfection efficiencies: gene gun biolistics. The gene gun transfection method was optimized for application to primary cultures of rat neonatal cardiomyocytes. Cells, cultured at different densities (0.75-1.50x10(5)cells/cm(2)) in serum-free medium, were transfected with DNA coated gold particles. A transfection efficiency of up to 10% could be achieved (compared to <1% with other methods) by the gene gun as checked using a RSV- beta-Gal construct. Cardiomyocytes were stimulated by endothelin-1 (ET-1) (10(-8)M) to induce hypertrophy, thereby yielding the characteristic changes in gene expression (upregulation of Atrial Natriuretic Factor (ANF) and downregulation of PL). The basal activity of an ANF promoter fragment (increasing from the lowest to highest density 2.6-fold) and its ET-1 inducibility (only significant upregulation of 2.6-fold, at lowest density) appeared to be dependent on the plating density of the cardiomyocytes. A PL promoter fragment was isolated, sequenced and 1.4 kb was subcloned in a luciferase reporter vector. The basal activity of the PL promoter fragment was not dependent on the plating density. ET-1 did not downregulate the PL promoter, rather a significant upregulation (1.4-fold) was found at the highest plating density. In conclusion, plating density of the cardiomyocytes can influence promoter activity as shown with an ANF promoter fragment. A newly isolated and sequenced rat PL promoter fragment did not direct gene expression as expected on basis of downregulation of the PL gene by ET-1 observed in this model.

In vitro analysis of SERCA2 gene regulation in hypertrophic cardiomyocytes and increasing transfection efficiency by gene-gun biolistics.

The transcriptional downregulation of the SERCA2 gene is studied using neonatal rat cardiomyocytes stimulated with endothelin-1 to induce hypertrophy. Liposome-based transfection of cells with a 1.9 kb SERCA2 promoter fragment directed expression of a reporter gene identical to the downregulation of genomic SERCA2 expression by endothelin-1. Results of a new gene gun technology for transient transfection of cardiomyocytes with a RSV-beta-galactosidase construct are reported. This new method for propelling DNA-coated gold beads into cardiomyocytes is extremely suitable for directly testing promoter/reporter gene DNA constructs since the transfection efficiency (approximately 10%) appears to be higher than traditional transfection methods.

Sarcoplasmic reticulum Ca2+ ATPase promoter activity during endothelin-1 induced hypertrophy of cultured rat cardiomyocytes.

OBJECTIVES: Characterization of an in vitro model of endothelin-1 induced hypertrophy of cultured neonatal rat ventricular myocytes and subsequent analysis of transcription regulation of the rat promoter of the sarcoplasmic reticulum Ca2+ ATPase gene. METHODS: Neonatal rat ventricular myocytes were cultured in serum free medium and hypertrophy was induced by addition of endothelin-1 to 10(-8) M up to 48 h. Hypertrophy was characterized biochemically, and gene expression regulation was evaluated by Northern blotting. A sarcoplasmic reticulum Ca2+ ATPase promoter fragment, isolated from a rat library was cloned in a reporter vector. Promoter activity during hypertrophy was assessed after transfection of the reporter plasmid to cultured cardiomyocytes. RESULTS: Stimulation with endothelin-1 resulted in increased cell size, as indicated by protein/DNA ratio as well as by augmented protein synthesis. When compared to angiotensin II or alpha 1-adrenergic agonist, endothelin-1 was the strongest inducer of hypertrophy (protein/DNA ratio) after 48 h of stimulation. Endothelin-1 induced hypertrophy was accompanied by a twofold increase in total RNA content per cell as well as to increased glyceraldehydephosphate dehydrogenase mRNA levels. The level of atrial natriuretic factor mRNA was increased more than twofold, relative to glyceraldehydephosphate dehydrogenase, while the expression of the sarcoplasmic reticulum Ca2+ pump and phospholamban genes was decreased (by 26 and 49%, respectively) after induction of hypertrophy by stimulation with endothelin-1. In the same model, a 1.9 kb sarcoplasmic reticulum Ca2+ pump gene promoter fragment (including 0.4 kb of the 5' UTR of the mRNA) directed down-regulation of the expression of the reporter gene to the same magnitude as endogenous Ca2+ pump mRNA relative to glyceraldehydephosphate dehydrogenase mRNA. However, absolute mRNA level per cell did not change for either the reporter gene or the endogenous Ca2+ pump. CONCLUSIONS: Endothelin-1 can induce phenotypic changes in cultured rat ventricular myocytes that are reminiscent of hypertrophy in vivo. In this model, a 1.9 kb sarcoplasmic reticulum Ca2+ pump promoter fragment directed gene expression of a reporter gene identical to the endogenous regulation of the Ca2+ pump. Furthermore, expression of the Ca2+ pump during hypertrophy was only downregulated when compared to (increased levels of) glyceraldehydephosphate dehydrogenase mRNA, but absolute Ca2+ ATPase mRNA amounts remained unchanged. This suggests that the Ca2+ pump promoter is not responding to the increase in transcriptional activity that accompanies hypertrophy.