RESUMEN
Nanoparticle-based voluminous 3D networks with low densities are a unique class of materials and are commonly known as aerogels. Due to the high surface-to-volume ratio, aerogels and xerogels might be suitable materials for applications in different fields, e.g. photocatalysis, catalysis, or sensing. One major difficulty in the handling of nanoparticle-based aerogels and xerogels is the defined patterning of these structures on different substrates and surfaces. The automated manufacturing of nanoparticle-based aerogel- or xerogel-coated electrodes can easily be realized via inkjet printing. The main focus of this work is the implementation of the standard nanoparticle-based gelation process in a commercial inkjet printing system. By simultaneously printing semiconductor nanoparticles and a destabilization agent, a 3D network on a conducting and transparent surface is obtained. First spectro-electrochemical measurements are recorded to investigate the charge-carrier mobility within these 3D semiconductor-based xerogel networks.
RESUMEN
Membranes from metal-organic frameworks (MOFs) are highly interesting for industrial gas separation applications. Strongly improved performances for carbon capture and H2 purification tasks in MOF membranes are obtained by using highly reproducable and very accuratly, hierarchically grown ZIF-8-on-ZIF-67 (ZIF-8@ZIF-67) nanostructures. To forgo hardly controllable solvothermal synthesis, particles and layers are prepared by self-assembling methods. It was possible for the first time to confirm ZIF-8-on-ZIF-67 membrane growth on rough and porous ceramic supports using the layer-by-layer deposition. Additionally, hierarchical particles are made in a fast RT synthesis with high monodispersity. Characterization of the hierarchical and epitaxial grown layers and particles is performed by SEM, TEM, EDXM and gas permeation. The system ZIF-8@ZIF-67 shows a nearly doubled H2 /CO2 separation factor, regardless of whether neat membrane or mixed-matrix-membrane in comparison to other MOF materials.
RESUMEN
Perovskite oxides have been under intense investigation as promising candidates for devices in the field of energy conversion and storage. Unfortunately, these perovskites are probably subjected to a frequent performance loss caused by phase transition. A phase-stabilization approach via interdiffusional tailoring is identified in perovskite-based composites. As an example, a phase-stabilized perovskite-fluorite composite material with both components possessing cubic symmetry was obtained by an appropriate one-pot strategy. These findings render possible to develop a high-performance and extremely stable dual-phase oxygen-transporting membrane for intermediate-temperature air separation as well as syngas production, which also opens up numerous opportunities to overcome the phase-transition-induced performance degradation in other systems.
RESUMEN
Water splitting coupled with partial oxidation of methane (POM) using an oxygen-transporting membrane (OTM) would be a potentially ideal way to produce high-purity hydrogen as well as syngas. Over the past decades, substantial efforts have been devoted to the development of supported membranes with appropriate configurations to achieve considerable performance improvements. Herein, we describe the design of a novel symmetrical membrane reactor with a sandwich-like structure, whereby a largescale production (>10â mL min(-1) cm(-2) ) of hydrogen and syngas can be obtained simultaneously on opposite sides of the OTM. Furthermore, this special membrane reactor could regenerate the coke-deactivated catalyst inâ situ by water steam in a single unit. These results represent an important first step in the development of membrane separation technologies for the integration of multiple chemical processes.
RESUMEN
To combine good chemical stability and high oxygen permeability, a mixed ionic-electronic conducting (MIEC) 75â wt% Ce(0.85)Gd(0.1)Cu(0.05)O(2-δ)-25â wt% La(0.6)Ca(0.4)FeO(3-δ)(CGCO-LCF) dual-phase membrane based on a MIEC-MIEC composite has been developed. Copper doping into Ce(0.9)Gd(0.1)O(2-δ) (CGO) oxide enhances both ionic and electronic conductivity, which then leads to a change from ionic conduction to mixed conduction at elevated temperatures. For the first time we demonstrate that an intergranular film with 2-10â nm thickness containing Ce, Ca, Gd, La, and Fe has been formed between the CGCO grains in the CGCO-LCF one-pot dual-phase membrane. A high oxygen permeation flux of 0.70â mL min(-1) cm(-2) is obtained by the CGCO-LCF one-pot dual-phase membrane with 0.5â mm thickness at 950 °C using pure CO2 as the sweep gas, and the membrane shows excellent stability in the presence of CO2 even at lower temperatures (800 °C) during long-term operation.
RESUMEN
Separation methods based on 2D interlayer galleries are currently gaining widespread attention. The potential of such galleries as high-performance gas-separation membranes is however still rarely explored. Besides, it is well recognized that gas permeance and separation factor are often inversely correlated in membrane-based gas separation. Therefore, breaking this trade-off becomes highly desirable. Here, the gas-separation performance of a 2D laminated membrane was improved by its partial self-conversion to metal-organic frameworks. A ZIF-8-ZnAl-NO3 layered double hydroxide (LDH) composite membrane was thus successfully prepared in one step by partial conversion of the ZnAl-NO3 LDH membrane, ultimately leading to a remarkably enhanced H2 /CH4 separation factor and H2 permeance.
RESUMEN
We develop here a urea hydrolysis method to in situ prepare asymmetric ZnAl-CO3 layered double hydroxide (LDH) buffer layers with various stable equilibrium morphology on porous Al2O3 substrates. In particular it is found that well-intergrown ZIF-8 membranes can be directly synthesized on the ZnAl-CO3 LDH buffer layer-modified substrates, owing to the specific metal-imidazole interaction between ZnAl-CO3 LDHs and ZIF-8. Other Zn-based MOF membranes, like ZIF-7 and ZIF-90, can also be synthesized with this method. Our finding demonstrates that LDH buffer layer represents a new concept for substrate modification.
Asunto(s)
Estimulantes del Sistema Nervioso Central , Infarto , Metanfetamina , Enfermedades Testiculares , Adolescente , Estimulantes del Sistema Nervioso Central/efectos adversos , Medios de Contraste , Humanos , Infarto/inducido químicamente , Infarto/diagnóstico por imagen , Masculino , Metanfetamina/efectos adversos , Enfermedades Testiculares/inducido químicamente , Enfermedades Testiculares/diagnóstico por imagen , UltrasonografíaRESUMEN
High-entropy perovskite oxides have already been studied in various fields owing to their high-entropy-induced properties. Partial substitution of an element by a lower valence element usually improves the oxygen permeability of perovskite oxides, but high substitution amounts may lead to structural instability. In this work, pure high-entropy perovskites Pr1-xSrx(Cr,Mn,Fe,Co,Ni)O3-δ with high amounts Sr up to x = 0.5 were synthesized via a sol-gel method. Several characterization methods prove that the solubility of Sr increases with higher temperatures of the heating treatment. The ceramic with x = 0.5 shows a transition from semi-conductive to metallic behavior when the temperature reaches 873K. Its oxygen flux is comparable to the low-entropy counterpart La0.6Sr0.4Co0.5Fe0.5O3-δ. A stable run of ca. 46.2 h was documented for oxygen permeation under an air/CO2 gradient.
RESUMEN
A novel neutral and cation-free LTA-type AlPO(4) membrane has been prepared on porous asymmetric ceramic supports. Hydrogen can be effectively separated from other gases by molecular sieving.
RESUMEN
Local anesthetic toxicity is a rare but serious complication of local anesthetic administration. Although lidocaine has a safety profile superior to other amide local anesthetics, we report a case of cardiac arrest after intranasal injection of lidocaine. The case involves a 22-year-old healthy woman who experienced pulseless electrical activity shortly after a submucosal injection of 2.2 mg/kg of lidocaine with epinephrine. Resuscitative efforts were unsuccessful until a bolus of intralipid was given. This case emphasizes that even a "low" dose of a less lipophilic drug has the potential for severe toxicity.
Asunto(s)
Anestésicos Locales/administración & dosificación , Epinefrina/administración & dosificación , Paro Cardíaco/inducido químicamente , Lidocaína/administración & dosificación , Administración Intranasal , Anestésicos Locales/efectos adversos , Epinefrina/efectos adversos , Emulsiones Grasas Intravenosas/administración & dosificación , Emulsiones Grasas Intravenosas/uso terapéutico , Femenino , Paro Cardíaco/tratamiento farmacológico , Humanos , Inyecciones , Lidocaína/efectos adversos , Resultado del Tratamiento , Adulto JovenRESUMEN
The 3D metal-organic framework (MOF) structure UiO-66 [Zr6O4(OH)4(bdc)6], featuring triangular pores of approximately 6 Å, has been successfully prepared as a thin supported membrane layer with high crystallographic orientation on ceramic α-Al2O3 supports. The adhesion of the MOF layer to the ceramic support was investigated in different taxing conditions. Furthermore, by coating this UiO-66 membrane with a thin polyimide (Matrimid) top layer, we prepared a multilayer composite. Said membranes have been evaluated in the separation of hydrogen (H2) from different binary mixtures at room temperature. H2 as the smallest molecule (2.9 Å) should pass the UiO-66 membrane preferably since the kinetic diameters of all the other gases under study are larger. The gas mixture separation factors for the neat UiO-66 membrane were indeed found to be H2/CO2 = 5.1, H2/N2 = 4.7, H2/CH4 = 12.9, H2/C2H6 = 22.4, and H2/C3H8 = 28.5. The coating with Matrimid led to a sharp cutoff for gases with kinetic diameters greater than 3.7 Å, resulting in increased separation performance.
RESUMEN
MOF membranes have gained widespread attention due to their unprecedented gas separation performance. Relying on physical interactions, we successfully deposited MOF seeds on a substrate modified with a network of vertically aligned LDH walls before secondary growth of the MOF layer. ZIF-8 membranes thus prepared show considerable H2 permeance with high H2-CH4 selectivity. This approach is in general suitable for the deposition of nanoparticles on solid surface and their subsequent growth into a dense layer.
Asunto(s)
Neoplasias Renales/cirugía , Procedimientos Quirúrgicos Mínimamente Invasivos/métodos , Nefrectomía/métodos , Diagnóstico por Imagen , Humanos , Neoplasias Renales/mortalidad , Neoplasias Renales/patología , Laparoscopía/métodos , Neoplasias Primarias Múltiples/mortalidad , Neoplasias Primarias Múltiples/patología , Neoplasias Primarias Múltiples/cirugía , Cuidados Posoperatorios , Complicaciones Posoperatorias/prevención & control , Pronóstico , Reoperación , Tasa de Supervivencia , Técnicas de Sutura , Ultrasonografía Intervencional/métodosRESUMEN
PURPOSE: A large hernia after flank incision for nephrectomy is a challenging problem in hernia surgery. In recent decades preperitoneal prosthetic herniorrhaphy became a widely accepted procedure for hernias of the abdominal wall. To evaluate the outcome of mesh hernia repair of the flank we reviewed our data on all patients who underwent preperitoneal mesh repair. MATERIALS AND METHODS: We identified 4 patients who underwent prosthesis repair after incisional hernia of the flank within the last 6 years. The primary reason for surgery was nephrectomy in 2 cases, pyeloplasty in 1 and complicated kidney cyst resection in 1. Mean followup time was 33 months. RESULTS: In a mean operative time +/- SD of 208 +/- 55 minutes the patients underwent incisional hernia repair with prosthesis implantation in the sublay position. In 3 patients an expanded polytetrafluoroethylene patch was used and in 1 polypropylene mesh was implanted. Mean prosthesis size was 25 x 38 cm. (950 +/- 300 cm. ). There were no postoperative complications. Patients were discharged from the hospital after a mean of 15 +/- 2 days. Followup revealed that none of the 4 patients with flank incision had recurrent hernia. Pain persisted in 3 patients after flank incision. However, no regular analgesic drug prescription was necessary. CONCLUSIONS: Mesh repair for incisional flank hernia provides reinforcement of the hernia. However, the flank remains paralyzed with a muscle bulge and some patients have persistent discomfort.