Carbon dioxide capture utilizing zeolites synthesized with paper sludge and scrap-glass.

The present work introduces the study of the CO2 capture process by zeolites synthesized from paper sludge and scrap glass. Zeolites ZSM-5, analcime and wairakite were produced by means of two types of Structure Directing Agents (SDA): tetrapropilamonium (TPA) and ethanol. On the one hand, zeolite ZSM-5 was synthesized using TPA; on the other hand, analcime and wairakite were produced with ethanol. The temperature programmed desorption (TPD) technique was performed for determining the CO2 sorption capacity of these zeolites at two sorption temperatures: 50 and 100 °C. CO2 sorption capacity of zeolite ZSM-5 synthesized at 50 °C was 0.683 mmol/g representing 38.2% of the value measured for a zeolite ZSM-5 commercial. Zeolite analcime showed a higher CO2 sorption capacity (1.698 mmol/g) at 50 °C and its regeneration temperature was relatively low. Zeolites synthesized in this study can be used in the purification of biogas and this will produce energy without increasing the atmospheric CO2 concentrations.

Nano-dimensional CeO2 nanorods for high Ni loading catalysts: H2 production by autothermal steam reforming of methanol reaction.

CeO2 nanorods were synthesized by a hydrothermal method and used as the support for preparing a series of Ni/CeO2 nanorod catalysts. The surface area of the catalysts decreased when the Ni percent over the CeO2 nanorods was increased. SEM results showed that the CeO2 is formed by nanorods approximately 1 µm in length. TEM and HREM revealed that the width of the nanorods is about 8 nm and it grew along the [1 1 1¯] axis. The catalytic activity of the catalysts was improved as the Ni was loaded onto CeO2 nanorods. The exposed planes of the CeO2 nanorod structure along the zone axis [0 1 1] for Ni impregnation were (1¯ 1¯ 1), (1 1 1¯), (1 1¯ 1), (1¯ 1 1¯), (2 0 0) and (2¯ 0 0) and they were more reactive for methanol conversion than (2¯ 2¯ 0), (2¯ 0 2¯), (0 2 2¯), (0 2¯ 2), (2 0 2) and (2 2 0) planes from the [1 1 1¯] axis (growth direction of the nanorod). This finding is mainly ascribed to the synergistic effect of the CeO2 nanorods and the Ni.

A novel synthesis method to produce silver-doped CeO2 nanotubes based on Ag nanowire templates.

Silver nanowires were used as templates to synthesize silver-doped CeO(2) (Ag-CeO(2)) nanotubes by the precipitation method. The precipitated solid was dried at 100 °C for 24 h and calcined at 500 °C for 5 h. A TEM, HRTEM, LV-SEM and XRD study was carried out to determine the micro and nanostructural characteristics of the samples. LV-SEM analysis allowed us to observe microtubular empty structures constituted by Ce, O and Ag as indicated by EDS. These tubular structures, with an external diameter from 120 to 280 nm and an internal diameter from 40 to 80 nm, were mainly composed of 11 nm ceria nanoparticles. This kind of structures was obtained when CeO(2) nanoparticles covered the Ag nanowires during the synthesis. Due to the presence of ammonium hydroxide used during the synthesis, a fraction of the silver nanowire reacts and Ag atoms begin to migrate outside the ceria microtube. When the sintering process is applied, the Kirkendall effect can occur. So, out-diffusion of the remnant Ag through the interface is faster than the in-diffusion of the shell material (CeO(2)), which eventually results in a coaxial nanotube on completion of the non-equilibrium interdiffusion, leaving the central core completely empty, driving the formation of hollow tubular Ag-CeO(2) structures as a result.

Infused cardioplegia index: A new tool to improve myocardial protection. A cohort study. / Índice de cardioplejía infundida: una nueva herramienta en la protección miocárdica. Un estudio de cohortes.

BACKGROUND: Strategies for cardio-protection are essential in coronary artery bypass graft surgery. The authors explored the relationship between cardioplegia volume, left ventricular mass index and ischemia time by means of the infused cardioplegia index and its relationship with post-operative low cardiac output syndrome. DESIGN: All patients undergoing coronary artery bypass graft surgery between January 2013 and December 2015 were included. Low cardiac output syndrome was defined according to criteria of the SEMICYUC's consensus document. The perioperative factors associated with low cardiac output syndrome were estimated, and using a ROC curve, the optimum cut-off point for the infused cardioplegia index to predict the absence of low cardiac output syndrome was calculated. RESULTS: Of 360 patients included, 116 (32%) developed low cardiac output syndrome. The independent risk predictors were: New York Heart Association Functional Classification (OR 1.8 [95% CI=1.18-2.55]), left ventricle ejection fraction (OR 0.95 (95% CI=0.93-0.98]), ICI (OR 0.99 [95% CI=0.991-0.996]) and retrograde cardioplegia (OR 1.2 [95% CI=1.03-1.50]). The infused cardioplegia index showed an area under the ROC curve of 0.77 (0.70-0.83; P<.001) for the absence of postoperative low cardiac output syndrome using the optimum cut-off point of 23.6ml·min-1(100g/m2 of LV)-1. CONCLUSIONS: The infused cardioplegia index presents an inverse relationship with the development of post-operative low cardiac output syndrome. This index could form part of new strategies aimed at optimising cardio-protection. The total volume of intermittent cardioplegia, especially that of maintenance, should probably be individualised, adjusting for ischemia time and left ventricle mass index.

Photocatalytic activity of Ag/Al2O3-Gd2O3 photocatalysts prepared by the sol-gel method in the degradation of 4-chlorophenol.

The photocatalytic activity in the degradation of 4-chlorophenol (4-ClPh) in aqueous medium (80 ppm) using 2.0 wt% Ag/Al2O3-Gd2O3 (Ag/Al-Gd-x; where x = 2.0, 5.0, 15.0, 25.0 and 50.0 wt% of Gd2O3) photocatalysts prepared by the sol-gel method was studied under UV light irradiation. The photocatalysts were characterized by N2 physisorption, X-ray diffraction, SEM, HRTEM, UV-Vis, XPS, FTIR and fluorescence spectroscopy. About 67.0% of 4-ClPh was photoconverted after 4 h of UV light irradiation using Ag/γ--Al2O3. When Ag/Al-Gd-x photocatalysts were tested, the 4-ClPh photoconversion was improved and more than 90.0% of 4-ClPh was photoconverted after 3 h of UV light irradiation in the materials containing 15.0 and 25.0 wt% of Gd2O3. Ag/Al-Gd-25 was the material with the highest efficacy to mineralize dissolved organic carbon, mineralizing more than 85.0% after 4 h of UV light irradiation. Silver nanoparticles and micro-particles of irregular pentagonal shape intersected by plane nanobelts of Al2O3-Gd2O3 composite oxide were detected in the Ag/Al-Gd-25 photocatalyst. This material is characterized by a lowest recombination rate of electron-hole pairs. The low recombination rate of photo-induced electron-hole pairs in the Ag/Al-Gd-x photocatalysts with high Gd2O3 contents (≥15.0 wt%) confirmes that the presence of silver nanoparticles and microparticles interacting with Al2O3-Gd2O3 composite oxide entities favors the separation of photo-induced charges (e- and h+). These materials could be appropriate to be used as highly efficient photocatalysts to eliminate high concentrations of 4-ClPh in aqueous medium.

Ag nanoparticle effects on the thermoluminescent properties of monoclinic ZrO(2) exposed to ultraviolet and gamma radiation.

The goal of this work was to analyse ZrO(2) in the pure state and when doped with Ag nanoparticles, by electron microscopy, x-ray diffraction and thermoluminescence methods. According to the results obtained, Ag nanoparticles did not modify the morphology or the crystalline structure of the ZrO(2). The thermoluminescent (TL) response of pure ZrO(2) showed two peaks, one at 334 K and the other at 417 K, when it was exposed to ultraviolet (UV) radiation, and at 342 and 397 K when gamma radiation was used. For ZrO(2) impregnated with Ag nanoparticles a diminished TL intensity due to nanoparticle shielding was observed, but the glow curve shape was similar. However, when Ag nanoparticles were added during the ZrO(2) synthesis, a shift of the TL peaks towards higher temperature values with reference to pure ZrO(2) was observed. A linear dependence of the integrated TL signal as a function of the irradiation dose was observed in all analysed samples. It was possible to determine some kinetic parameters, such as activation energy, kinetic order and frequency factor, using the sequential quadratic programming glow curve deconvolution; it was found that these values are highly dependent on the type of radiation used. Ag nanoparticles present in ZrO(2) also modified the kinetic parameters, mainly when they were added during the synthesis of ZrO(2). Our results reinforce the possibilities of using pure and doped ZrO(2) as an appropriate dosimetric material in radiation physics.

[Two case studies of neuroleptic malignant syndrome]. / Estudio de dos casos de síndrome maligno por neurolépticos.

We present two cases of neuroleptic malignant syndrome (NMS). In the first one, we have a patient, female, of fifty years old, with hypertension and diagnosed of schizophrenic psychosis since twenty year ago. In the second one, the patient, female too, of twenty-five years old, without antecedents neither psychiatric nor organic that on interest. She is pregnant of six or seven weeks. It is analysed the guide-line of neuroleptics that could possibly originate the NMS, as well as the evolution of the symptoms of that syndrome after being applicated the therapy. The clinical judgement followed is discussed so far the diagnosis has become firm.

The role of surgery in stage IV neuroblastoma.

BACKGROUND/PURPOSE: The importance of primary tumor resection in stage IV neuroblastoma is controversial. The authors analyzed prospectively the role of surgery in a multicentric series of stage IV neuroblastoma patients. METHODS: Patients were studied according to the International Neuroblastoma Staging System (INSS) recommendations. Age, sex, location of the tumor, type of metastases, time of resection (initial or delayed), extension of resection, surgical complications, pathology, N-myc and Shimada classification results, relapses, and outcome were studied. After diagnosis, children received induction chemotherapy followed by delayed surgery and autologous stem cell transplantation or maintenance chemotherapy. Resection was classified as complete (C), greater than 90% (P1), greater than 50% (P2), less than 50% (P3), and biopsy (B). RESULTS: Ninety-eight stage IV children were admitted in the study from June 1992 to July 1999. Seventy-six were older than one year, and in 78 the primary tumor was abdominal. Bone was the most common metastatic site followed by bone marrow. Initial biopsy was performed in 74 patients, and resection in 6, with one complication in each group. N-myc was amplified in 20 of 80 tumors, and Shimada was unfavorable in 45 of 67. Delayed surgery was performed in 70 cases, achieving gross total resection in 55 (79%); there were minor complications in 10%. Mean survival rate time was 50 months. Event-free survival rate (EFS) at 5 years for the entire series is 0.32, but 0.0 for children having biopsy only, 0.25 for less than 50% resection, 0.31 for 50% to 90% resection, 0.44 for greater than 90% resection, and 0.33 for complete resection. Differences were statistically significant only when compared with the biopsied group. EFS rate for infants was 0.56, but, again, there was no difference in relation to the type of resection. There were 46 relapses, 12 of them local, 7 of 20 N-myc-amplified tumors, and 4 of 60 not amplified (P <.005). CONCLUSIONS: Biopsies of stage IV neuroblastoma allow safe assessment of N-myc and other biological factors on tumor tissue. Delayed surgery after chemotherapy is performed with a low rate of complications, achieving a good local control of disease. N-myc-amplified tumors have higher local relapse rates than nonamplified and therefore would need more intensive local treatment. The final outcome in these patients is determined more by metastatic relapses than by the degree of resection.