Spectroscopic analysis of the transverse excited C3Πu–B3Πg(0–0) UV laser band of N2 at room temperature: comments

Recently Petit et al.published a paper devoted to a high-resolution spectroscopy study of the 0-0 laser band in the Second Positive System of molecular nitrogen and explaining the optical gain formation on its different branches.All the results by Petit et al. are equivalent to those previously published by Massone et al.and are in accordance with theoretical predictions reported by Tocho et al.Summarizing, we would comment as follows

A Xenon Ion Pumped Open Dye Stream Laser

A pulsed xenon ion laser with an output power of 1 kW over the blue-green lines was used to pump an open dye stream laser. An efficiency of the order of 40 percent was determined in broadband mode operation. The bandwidth in this case was 48 nm (from 582 to 630 nm)

Enhancement of photoacoustic detection of inhomogeneities in polymers

We report a series of experiments on laser pulsed photoacoustic excitation in turbid polymer samples addressed to evaluate the sound speed in the samples and the presence of inhomogeneities in the bulk. We describe a system which allows the direct measurement of the speed of the detected waves by engraving the surface of the piece under study with a fiduciary pattern of black lines. We also describe how this pattern helps to enhance the sensitivity for the detection of an inhomogeneity in the bulk. These two facts are useful for studies in soft matter systems including, perhaps, biological samples. We have performed an experimental analysis on Grilon®samples in different situations and we show the limitations of the method.Facultad de Ingenierí

Alineación empleando un sistema óptico de enfoque y un láser.

Se describe un método de alineación empleando un láser de He-Ne ($latex \lambda$= 632,8 nm, P = 2 mW) acoplado a un sistema telescópico que permite enfocar el haz luminoso hasta obtener puntos 'brillantísimos de diámetros mucho menores que 50 μm. Se analiza su aplicación a la deter· minación de rectas, planos y relaciones entre ellos (paralelismo, perpendicularidad, etc.). Se detalla su utilización en dos casos concretos: a) Verificación de la alineación del cigüeñal del motor principal de un buque frigorífico surto en el puerto de Buenos Aires (Argentina), y b) Verificación de la colinealidad entre los ejes de dos cojinetes de un tubo de timón de un barco en construcción en el Astillero Río Santiago (Argentina)

Morphology and thermal stability of alf3 on Cu(100) thin films

Se estudió el crecimiento de películas epitaxiales ultra-delgadas de fluoruro de aluminio en Cu (100) mediante una combinación de técnicas experimentales de física de superficies. La deposición a temperatura ambiente resulta en la decoración de escalones seguida por la formación de islas dendríticas bidimensionales que coalescen para formar películas porosas. Las películas ultra-delgadas (de hasta dos monocapas de espesor) resultan morfológicamente inestables al calentar; parte de la película deja de mojar la superficie del sustrato a alrededor de 430 K con la formación de islas tridimensionales y dejando expuesta un área extensa de la superficie de Cu. En cambio, películas de varios nanómetros de espesor son estables hasta temperaturas cercanas a los 730 K cuando ocurre la desorción molecular. El efecto de la irradiación electrónica también ha sido caracterizado mediante diferentes técnicas espectroscópicas; encontrando que incluso dosis de irradiación reducidas de electrones pueden producir una descomposición significativa del fluoruro de aluminio, resultando en la liberación de moléculas de flúor y la formación de aluminio metálico. Estas características hacen del fluoruro de aluminio un material interesante para aplicaciones en espintrónica.Fil: Ruano Sandoval, Gonzalo Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química (i); ArgentinaFil: Moreno López, Juan Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química (i); ArgentinaFil: Passeggi, Mario Cesar Guillermo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química (i); ArgentinaFil: Vidal, Ricardo Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química (i); ArgentinaFil: Ferron, Julio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química (i); ArgentinaFil: Niño, M. A.. Universidad Autónoma de Madrid; EspañaFil: Miranda, R.. Universidad Autónoma de Madrid; EspañaFil: de Miguel, J. J.. Universidad Autónoma de Madrid; Españ

Malformaciones del macizo facial en la oveja

[ES] Malformaciones del macizo facial en la ovej

Enhancement of photoacoustic detection of inhomogeneities in polymers

We report a series of experiments on laser pulsed photoacoustic excitation in turbid polymer samples addressed to evaluate the sound speed in the samples and the presence of inhomogeneities in the bulk. We describe a system which allows the direct measurement of the speed of the detected waves by engraving the surface of the piece under study with a fiduciary pattern of black lines. We also describe how this pattern helps to enhance the sensitivity for the detection of an inhomogeneity in the bulk. These two facts are useful for studies in soft matter systems including, perhaps, biological samples. We have performed an experimental analysis on Grilon®samples in different situations and we show the limitations of the method.Facultad de Ingenierí

Morphological, Electrical, and Chemical Characteristics of Poly(sodium 4-styrenesulfonate) Coated PVDF Ultrafiltration Membranes after Plasma Treatment

A commercial ultrafiltration (UF) membrane (HFM-183 de Koch Membrane Systems) made of poly(vinylidene fluoride) (PVDF), was recovered with a negatively-charged polyelectrolyte (poly(sodium 4-styrenesulfonate)) (PSS), and the effects on its electric, chemical, and morphological properties were analyzed. Atomic force microscopy (AFM), liquid-liquid displacement porometry, Electrical Impedance Spectroscopy, X-ray photoelectron spectroscopy, and Raman spectroscopy were used to investigate the modifications induced by the deposition of PSS on the PVDF positively-charged membrane and after its treatment by a radio frequency Ar-plasma. These techniques confirmed a real deposition and posterior compaction of PSS with increasing roughness and decreasing pore sizes. The evolution of the electric resistances of the membranes confirmed crosslinking and compaction with shielding of the sulfonated groups from PSS. In this way, a membrane with a negatively-charged active layer and a pore size which was 60% lower than the original membrane was obtained. The composition of the additive used by manufacturers to modify PVDF to make it positively charged was obtained by different procedures, all of which depended upon the results of X-ray photoelectron spectroscopy, leading to fairly consistent results. This polymer, carrying positive charges, contains quaternary nitrogen, as confirmed by XPS. Moreover, Raman spectroscopy confirmed that PVDF changes from mostly the β to the α phase, which is more stable as a substrate for the deposited PSS. The aim of the tested modifications was to increase the retention of divalent anions without reducing permeability.Fil: Sandoval Olvera, Ivette G.. Universidad de Guanajuato; MéxicoFil: González Muñoz, Pilar. Universidad de Guanajuato; MéxicoFil: Diaz, Dario Ramón. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich". Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich"; ArgentinaFil: Maroto Valiente, Ángel. Universidad de Guanajuato; MéxicoFil: Ochoa, Nelio Ariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich". Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich"; ArgentinaFil: Carmona, Francisco J.. Universidad de Extremadura; EspañaFil: Palacio, Laura. Universidad de Valladolid. Facultad de Ciencias; EspañaFil: Calvo, José I.. Universidad de Valladolid. Facultad de Ciencias; EspañaFil: Hernández, Antonio. Universidad de Valladolid. Facultad de Ciencias; EspañaFil: Ávila Rodríguez, Mario. Universidad de Guanajuato; MéxicoFil: Prádanos, Pedro. Universidad de Valladolid. Facultad de Ciencias; Españ

Early liver function improvement following successful treatment of chronic hepatitis C in patients with decompensated cirrhosis: a real-life study

OBJECTIVES: Despite higher rates of sustained virologic response (SVR), important concerns remain when patients with decompensated cirrhosis due to hepatitis C virus (HCV) are treated with direct-acting antiviral agents (DAA). Questions include efficacy, safety, and the magnitude of liver function improvement. Here, we aimed to evaluate HCV treatment data in this specific population in Brazil. METHODS: We included 85 patients with decompensated cirrhosis submitted to HCV therapy with DAA followed at two academic tertiary centers in the southeastern region of Brazil. RESULTS: Seventy-nine patients (92.9%) were Child-Pugh (CP) score B, and six (7.1%) were CP score C. The mean MELD score was 12.86. The most common treatment was sofosbuvir plus daclatasvir±ribavirin for 24 weeks. The overall intention-to-treat (ITT) SVR rate was 87.4% (74/85) and modified-ITT 96.1% (74/77). ITT SVR was associated with lower baseline INR values (p=0.029). Adverse events (AE) occurred in 57.9% (44/76) of patients. Serious AE were reported in 12.8% (10/78), and were related to the presence of hepatic encephalopathy (p=0.027). SVR was associated with improvement in CP (p<0.0001) and MELD scores (p=0.021). Among baseline CP score B patients with SVR, 46% (29/63) regressed to CP score A. Ascites was independently associated with no improvement in liver function in patients who achieved SVR (p=0.001; OR:39.285; 95% CI:4.301-258.832). CONCLUSIONS: Patients with decompensated HCV cirrhosis showed a high SVR rate with interferon-free therapy. Early liver function improvement occurred after successful HCV eradication. However, long-term follow-up of these patients after SVR remains strongly advised. &nbsp