Publications by authors named "Diaz U"

Article Synopsis
  • Novel lamellar chalcogenide materials, ITQ-75, are developed from tin and zinc sulfide using hydro(solvo)thermal methods and N-heterocyclic aromatic agents.
  • Characterization involved metal doping and modifying the synthesis gel’s composition to improve electronic structure and accessibility, achieving optical band gaps around 2.0 eV for effective solar fuel production.
  • The optimized ITQ-75 materials exhibited high photocatalytic performance in water-splitting reactions for hydrogen generation, demonstrating efficiency levels among the best yet, confirming their potential as effective photocatalysts for solar energy applications.
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This study reports on a metal-free Covalent Triazine Framework (CTF) incorporating bithiophene structural units (TP-CTF) with a semicrystalline structure as an efficient heterogeneous photocatalyst under visible light irradiation. The physico-chemical properties and composition of this material was confirmed via different characterization solid-state techniques, such as XRD, TGA, CO adsorption and FT-IR, NMR and UV-Vis spectroscopies. The compound was synthesized through a solvothermal process and was explored as a heterogeneous photocatalyst for the oxidative coupling of amines to imines under visible light irradiation.

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Two series of MCM-36 zeolites intercalated with various pillars and modified with iron were synthesized, analyzed with respect to their physicochemical properties, and tested as catalysts for the NH-SCR process. It was found that the characteristic MWW morphology of MCM-36 can be obtained successfully using silica, alumina, and iron oxide as pillars. Additionally, one-pot synthesis of the material with iron resulted in the incorporation of monomeric Fe species into the framework positions.

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We present the one-pot synthesis of functionalized organosilica nanoparticles to generate multi-functional hybrid catalysts. Octadecyl, alkyl-thiol and alkyl-amino moieties were used separately and in different combinations, to generate different hybrid spherical nanoparticles with tunable acidic, basic and amphiphilic properties, covalently incorporating up to three organic functional elements onto the surface of the nanoparticles. Several parameters were optimised such as the concentration of the base employed during the hydrolysis and condensation synthesis process that showed a strong influence on the particle size.

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A series of clinoptilolite-supported catalysts, modified with hydrotalcite-like phase (HT) by co-precipitation, were prepared and tested in NH-SCR reactions. It was found that deposition of HT on clinoptilolite increased conversion of NO within 250-450 °C, and that the positive impact on the catalytic activity was independent of HT loading. The promoting effect of clinoptilolite was attributed to Brönsted acid sites present in the zeolite, which facilitated adsorption and accumulation of ammonia during the catalytic process.

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The catalytic performance of Fe-catalysts in selective catalytic reduction of nitrogen oxides with ammonia (NH-SCR) strongly depends on the nature of iron sites. Therefore, we aimed to prepare and investigate the catalytic potential of Fe-MCM-22 with various Si/Fe molar ratios in NH-SCR. The samples were prepared by the one-pot synthesis method to provide high dispersion of iron and reduce the number of synthesis steps.

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The giant ciliate Stentor coeruleus is a classical model system for studying regeneration and morphogenesis in a single cell. The anterior of the cell is marked by an array of cilia, known as the oral apparatus, which can be induced to shed and regenerate in a series of reproducible morphological steps, previously shown to require transcription. If a cell is cut in half, each half regenerates an intact cell.

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The application of layered zeolites of MWW topology in environmental catalysis has attracted growing attention in recent years; however, only a few studies have explored their performance in selective catalytic reduction with ammonia (NH-SCR). Thus, our work describes, for the first time, the one-pot synthesis of Fe-modified NH-SCR catalysts supported on MCM-22, MCM-36, and ITQ-2. The calculated chemical composition of the materials was Si/Al of 30 and 5 wt.

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Cellular components are non-randomly arranged with respect to the shape and polarity of the whole cell. Patterning within cells can extend down to the level of individual proteins and mRNA. But how much of the proteome is actually localized with respect to cell polarity axes? Proteomics combined with cellular fractionation has shown that most proteins localize to one or more organelles but does not tell us how many proteins have a polarized localization with respect to the large-scale polarity axes of the intact cell.

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Titanium-silicon ferrierites with different Si/Ti ratios and their delaminated forms were modified with copper by ion-exchange. The obtained samples were characterized with respect to their chemical composition (ICP-OES), structure (XRD), texture (N sorption), morphology (SEM), form and aggregation of titanium and copper species (UV-vis-DRS), reducibility of deposited copper species (H-TPR) and surface acidity (NH-TPD). The porous structure of the zeolitic samples strongly influenced the form and aggregation of deposited copper species.

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Article Synopsis
  • * The study found that the UV-visible absorption spectra show various forms of DCM molecules, while the emission spectra shift with increased DCM concentration, indicating the formation of aggregates.
  • * Notably, the DCM/Al-ITQ-HB composites can sense vapors of certain aromatic amine compounds through a unique electron transfer process, offering potential applications in detecting aniline derivatives.
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Modern approaches in quantitative live cell imaging have become an essential tool for exploring cell biology, by enabling the use of statistics and computational modeling to classify and compare biological processes. Although cell culture model systems are great for high content imaging, high throughput studies of cell morphology suggest that ex vivo cultures are limited in recapitulating the morphological complexity found in cells within living organisms. As such, there is a need for a scalable high throughput model system to image living cells within an intact organism.

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Ferrierites and their delaminated forms (ITQ-6), containing aluminum or titanium in the zeolite framework, were synthetized and modified with copper by an ion-exchange method. The obtained samples were characterized with respect to their chemical composition (ICP-OES), structure (XRD, UV-Vis DRS), textural parameters (N-sorption), surface acidity (NH-TPD), form and reducibility of deposited copper species (UV-Vis DRS and H-TPR). Ferrierites and delaminated ITQ-6 zeolites modified with copper were studied as catalysts for the selective catalytic oxidation of ammonia to dinitrogen (NH-SCO).

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MCM-22, MCM-36, and ITQ-2 zeolites with the intended Si/Al molar ratios of 15, 25, and 50 were synthetized and tested as catalysts for dehydration of methanol to dimethyl ether and dehydration of ethanol to diethyl ether and ethylene. The surface concentration of acid sites was regulated by the synthesis of zeolite precursors with different aluminum content in the zeolite framework, while the influence of porous structure on the overall efficiency of alcohol conversion was analyzed by application of zeolitic materials with different types of porosity-microporous MCM-22 as well as microporous-mesoporous MCM-36 and ITQ-2. The zeolitic samples were characterized with respect to their: chemical composition (ICP-OES), structure (XRD, FT-IR), texture (N sorption), and surface acidity (NH-TPD).

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In this work, an MWW-type zeolite with pillars containing silicon and niobium oxide was synthesized to obtain a hierarchical zeolite. The effect of niobium insertion in the pillaring process was determined by combining a controllable acidity and accessibility in the final material. All pillared materials had niobium occupying framework positions in pillars and extra-framework positions.

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During mitosis, the structure of the Endoplasmic Reticulum (ER) displays a dramatic reorganization and remodeling, however, the mechanism driving these changes is poorly understood. Hairpin-containing ER transmembrane proteins that stabilize ER tubules have been identified as possible factors to promote these drastic changes in ER morphology. Recently, the Reticulon and REEP family of ER shaping proteins have been shown to heavily influence ER morphology by driving the formation of ER tubules, which are known for their close proximity with microtubules.

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Different metalorganic lamellar hybrid materials based on associated nanoribbons were synthesized by the use of alkyl-benzyl monocarboxylate spacers, containing alkyl tails with variable lengths, which acted like structural growing inhibitors. These molecular agents were perpendicularly located and coordinated to aluminium nodes in the interlayer space, controlling the separation between individual structure sub-units. The hybrid materials were studied by X-ray diffraction (XRD), chemical and thermogravimetrical analysis (TGA), nuclear magnetic resonance (NMR) and infrared spectroscopy (IR), and field emission scanning electron microscopy (FESEM)/transmission electron microscopy (TEM), showing their physicochemical properties.

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Novel MOF-type materials with different morphologies based on assembled 1D organic-inorganic sub-domains were prepared using specific monodentate benzylcarboxylate spacers with functional substituents in the para-position as structure modulating agents. The combination of electron-withdrawing or electron-donating functions in the organic spacers with suitable solvothermal synthesis conditions allowed modulating the structuration level (2D or 3D), vacancies, physico-chemical properties and Lewis acidity strength of the metal-organic structures. Furthermore, bimetallic (Al/Fe) MOF-type materials were synthesized by a one-pot direct process without modification of the structural framework.

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A new chiral mesoporous hybrid material was synthesized based on pyrrolidine units included in a siliceous framework, HybPyr, and integrated into the organic-inorganic structure, from a specific bis-silylated precursor. A fluoride sol-gel methodology under soft synthesis conditions and in the absence of sophisticated structural directing agents allowed the generation of a mesoporous architecture with a homogeneous distribution of active chiral moieties along the network. The hybrid material was studied by means of different characterization techniques (TGA, NMR and IR spectroscopy, chemical and elemental analyses, TEM, and textural measurements), verifying the stability and integrity of the asymmetric active sites in the solid.

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The distribution and interactions of organic molecules adsorbed on the surface of materials play important roles in many catalytic and photonic processes. Here, we show that the length and chemical structure of the linker in new Al-ITQ metal-organic frameworks (MOFs) are fundamental for the dynamics of the dye Nile Red (NR) adsorbed on its surface. For the studied composites using Al-ITQ-4-ethylbenzoic acid (EB), Al-ITQ-4-aminobenzoic acid (AB), and Al-ITQ-EB exposed to the aniline (AN) or N, N-dimethylaniline (DMA) atmospheres, we observed a very fast (∼1.

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Cells need to be able to regenerate their parts to recover from external perturbations. The unicellular ciliate Stentor coeruleus is an excellent model organism to study wound healing and subsequent cell regeneration. The Stentor genome became available recently, along with modern molecular biology methods, such as RNAi.

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The chemistry between layered MWW zeolite and carbon black pearls (BP 2000) as an inexpensive hard template was investigated to develop a rational one-pot synthesis of MCM-22 microspheres. The characterization results showed that the insertion of BP 2000 in the gel synthesis did not substantially compromise the crystallinity and microporosity, and the microscopic analyses showed that BP 2000 played a key role in controlling the final morphology of the MCM-22 zeolite, creating beautiful dandelion-like microspherical particles. The morphology obtained is due to the tortuous shape of the hard template, the particular MWW particle crystals, the interaction with the external surface of the MWW zeolitic precursor, and the synthesis conditions.

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Article Synopsis
  • This study investigates how the two-dimensional Al-ITQ-4-heptylbenzoic acid (HB) metal-organic framework (MOF) affects the interactions of Nile red (NR) molecules adsorbed on its surface.
  • Time-resolved emission experiments reveal that energy transfer between NR molecules occurs with long time constants that shorten as NR concentration increases, indicating processes like charge transfer and aggregation are at play.
  • Femtosecond studies show a rapid intramolecular charge transfer process in the NR@Al-ITQ-HB composites, suggesting that the unique surface properties of this MOF contribute significantly to its high catalytic effectiveness, offering insights for future research on MOFs and their photocatalytic
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Novel aluminium MOF-type materials structured by 1D subdomains, such as organic-inorganic nanoribbons, were synthesized by modifying the conditions of solvothermal synthesis and the nature of the solvents in the presence of aryl monocarboxylate linkers with long alkyl chains, which acted as growth-modulating agents. Specifically, three different families of materials were prepared with various morphological characteristics: (i) isoreticular MIL-53(Al)-type materials, (ii) mesoscopic metalorganic structures and (iii) lamellar aluminium MOFs. The length of the alkyl chain in the aryl linker and the hydrophobic/hydrophilic nature of the solvothermal synthesis media determined the structuration level that was achieved.

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In this work, we unravel the photodynamics of Nile Red (NR) interacting with Al-ITQ-HB nanostructure, a new layer-type metal-organic framework (MOF) with potential catalytic and photonic applications. Steady-state spectroscopy reveals the presence of NR monomers and aggregates when interacting with the MOF structure. Time-resolved experiments provide emission lifetimes of the interacting monomers, H- and J-type aggregates.

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