Publications by authors named "Daniel Resasco"

The high prevalence of breast cancer is a global health concern, compounded by the lack of safe or effective treatments for its advanced stages. These facts urge the development of novel treatment strategies. Annexin A5 (ANXA5) is a natural human protein that binds with high specificity to phosphatidylserine, a phospholipid tightly maintained in the inner leaflet of the cell membrane on most healthy cells but externalized in tumor cells and the tumor vasculature.

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Aqueous-phase postsynthetic modifications of the industrially important Y-type zeolite are commonly used to change overall acid site concentrations, introduce stabilizing rare-earth cations, impart bifunctional character through metal cation exchange, and tailor the distribution of Brønsted and Lewis acid sites. Zeolite Y is known to undergo framework degradation in the presence of both vapor- and liquid-phase water at temperatures exceeding 100 °C, and rare-earth exchanged and stabilized HY catalysts are commonly used for fluidized catalytic cracking due to their increased hydrothermal resilience. Here, using detailed spectroscopy, crystallography, and flow-reactor experiments, we reveal unexpected decreases in Brønsted acid site (BAS) density for zeolite HY following exposure even to room-temperature liquid water.

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Balancing kinetics, a crucial priority in catalysis, is frequently achieved by sacrificing activity of elementary steps to suppress side reactions and enhance catalyst stability. Dry reforming of methane (DRM), a process operated at high temperature, usually involves fast C-H activation but sluggish carbon removal, resulting in coke deposition and catalyst deactivation. Studies focused solely on catalyst innovation are insufficient in addressing coke formation efficiently.

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The greatest contributors to cancer mortality are metastasis and the consequences of its treatment. Here, we present a novel treatment of metastatic breast cancer that combines photothermal therapy with targeted single-walled carbon nanotubes (SWCNTs) and immunostimulation with a checkpoint inhibitor. We find that the selective near-infrared photothermal ablation of primary orthotopic EMT6 breast tumors in syngeneic BALB/cJ mice using an annexin A5 (ANXA5) functionalized SWCNT bioconjugate synergistically enhances an anti-cytotoxic T-lymphocyte-associated protein 4 (anti-CTLA-4)-dependent abscopal response, resulting in an increased survival (55%) at 100 days after tumor inoculation.

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We report a reaction platform for the synthesis of three different high-value specialty chemical building blocks starting from bio-ethanol, which might have an important impact in the implementation of biorefineries. First, oxidative dehydrogenation of ethanol to acetaldehyde generates an aldehyde-containing stream active for the production of C aldehydes via base-catalyzed aldol-condensation. Then, the resulting C adduct is selectively converted into crotonic acid via catalytic aerobic oxidation (62 % yield).

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Cobalt-manganese (CoMn) oxides obtained through a one-pot synthesis can be controllably reduced to CoxMn1-xO nanocrystals for the direct production of C2-C4 olefins with high selectivity (50.9 mol%) from syngas at high CO conversion (92.4%), higher than predicted by the Anderson-Schulz-Flory distribution.

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Ordered-hexagonal silica materials, such as Mobil crystalline material-41 and Santa Barbara amorphous-15, have important applications in heterogeneous catalysis and biomass conversion due to their chemical stability and mesoporous structure. Low-temperature grafting (LG) is one of the most common functionalization methods used to modify the acidity/basicity or hydrophobicity/hydrophilicity of the surface. However, the materials prepared by this method are prone to leaching of functional groups into the reaction medium.

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Bladder cancer has a 60%-70% recurrence rate most likely due to any residual tumour left behind after a transurethral resection (TUR). Failure to completely resect the cancer can lead to recurrence and progression into higher grade tumours with metastatic potential. We present here a novel therapy to treat superficial tumours with the potential to decrease recurrence.

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Acylation is an effective C-C bond-forming reaction to condense acetic acid and lignin-derived aromatic compounds into acetophenones, valuable precursors to fuels and chemicals. However, acetic acid is intrinsically an ineffective acylating agent. Here, we report that its acylation activity can be greatly enhanced by forming intermediate aromatic esters directly derived from acetic acid and phenolic compounds.

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The simultaneous conversion of cyclopentanone and m-cresol has been investigated on a series of solid-acid catalysts. Both compounds are representative of biomass-derived streams. Cyclopentanone can be readily obtained from sugar-derived furfurals through Piancatelli rearrangement under reducing conditions.

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A new type of catalyst has been designed to adjust the basicity and level of molecular confinement of KNaX faujasites by controlled incorporation of Mg through ion exchange and precipitation of extraframework MgO clusters at varying loadings. The catalytic performance of these catalysts was compared in the conversion of C2 and C4 aldehydes to value-added products. The product distribution depends on both the level of acetaldehyde conversion and the fraction of magnesium as extraframework species.

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The susceptibility of zeolites to hot liquid water may hamper their full utilization in aqueous phase processes, such as those involved in biomass conversion and upgrading reactions. Interactions of zeolites with water strongly depend on the presence of hydrophilic moieties including Brønsted acid sites (BAS), extraframework cations, and silanol defects, which facilitate wetting of the surface. However, it is not clear which of these moieties are responsible for the susceptibility of zeolites to liquid water.

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The independent evaluation of catalyst activity and stability during the catalytic pyrolysis of biomass is challenging because of the nature of the reaction system and rapid catalyst deactivation that force the use of excess catalyst. In this contribution we use a modified pyroprobe system in which pulses of pyrolysis vapors are converted over a series of HZSM-5 catalysts in a separate fixed-bed reactor controlled independently. Both the reactor-bed temperature and the Si/Al ratio of the zeolite are varied to evaluate catalyst activity and deactivation rates independently both on a constant surface area and constant acid site basis.

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Fast pyrolysis of biomass to produce a bio-oil followed by catalytic upgrading is a widely studied approach for the potential production of fuels from biomass. Because of the complexity of the bio-oil, most upgrading strategies focus on removing oxygen from the entire mixture to produce fuels. Here we report a novel method for the production of the specialty chemical, gluconic acid, from the pyrolysis of biomass.

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This paper focuses on the targeting of single-walled carbon nanotubes (SWNTs) for the treatment of breast cancer with minimal side effects using photothermal therapy. The human protein annexin V (AV) binds specifically to anionic phospholipids expressed externally on the surface of tumour cells and endothelial cells that line the tumour vasculature. A 2 h incubation of the SWNT-AV conjugate with proliferating endothelial cells followed by washing and near-infrared (NIR) irradiation at a wavelength of 980 nm was enough to induce significant cell death; there was no significant cell death with irradiation or the conjugate alone.

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Because of their unique physical, chemical, and electrical properties, carbon nanotubes are an attractive material for many potential applications. Their interactions with biological entities are, however, not yet completely understood. To fill this knowledge gap, we present experimental results for aqueous systems containing single-walled carbon nanotubes and phospholipid membranes, prepared in the form of liposomes.

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HY zeolites hydrophobized by functionalization with organosilanes are much more stable in hot liquid water than the corresponding untreated zeolites. Silylation of the zeolite increases hydrophobicity without significantly reducing the density of acid sites. This hydrophobization with organosilanes makes the zeolites able to stabilize water/oil emulsions and catalyze reactions of importance in biofuel upgrading, i.

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The atomic specificity afforded by nuclear magnetic resonance (NMR) spectroscopy could enable detailed mechanistic information about single-walled carbon nanotube (SWCNT) functionalization as well as the noncovalent molecular interactions that dictate ground-state charge transfer and separation by electronic structure and diameter. However, to date, the polydispersity present in as-synthesized SWCNT populations has obscured the dependence of the SWCNT (13)C chemical shift on intrinsic parameters such as diameter and electronic structure, meaning that no information is gleaned for specific SWCNTs with unique chiral indices. In this article, we utilize a combination of (13)C labeling and density gradient ultracentrifugation (DGU) to produce an array of (13)C-labeled SWCNT populations with varying diameter, electronic structure, and chiral angle.

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A detailed knowledge of the manifold of both bright and dark excitons in single-walled carbon nanotubes (SWCNTs) is critical to understanding radiative and nonradiative recombination processes. Exciton-phonon coupling opens up additional absorption and emission channels, some of which may "brighten" the sidebands of optically forbidden (dark) excitonic transitions in optical spectra. In this report, we compare (12)C and (13)C-labeled SWCNTs that are highly enriched in the (6,5) species to identify both absorptive and emissive vibronic transitions.

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An immunologically modified nanotube system was developed using an immunoadjuvant, glycated chitosan (GC), as surfactant of single-walled carbon nanotube (SWNTs). This SWNT-GC system not only retained both optical properties of SWNTs and immunological functions of GC, but also could enter cells due to the carrier properties of SWNTs. Cellular SWNTs induced thermal destruction of tumor cells when irradiated by a near-infrared laser and, at the same time, cellular GC could serve both as damage associated molecular pattern molecules (DAMPs) and pathogen associated molecular pattern molecules (PAMPs) to enhance the tumor immunogenicity and enhance the uptake and presentation of tumor antigens, leading to special antitumor response.

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A new approach for targeting carbon nanotubes to the tumor vasculature was tested using human endothelial cells and MCF-7 breast cancer cells in vitro. Single-walled carbon nanotubes were functionalized with the F3 peptide using a polyethylene glycol linker to target nucleolin, a protein found on the surface of endothelial cells in the vasculature of solid tumors. Confocal microscopy and Raman analysis confirmed that the conjugate was internalized by actively dividing endothelial cells.

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Nanohybrids composed of "onion-like" carbon, single-walled (SWCNTs) or multi-walled carbon nanotubes (MWCNTs) fused to silica or alumina particles have been compared as stabilizers of water/oil emulsions and interfacial catalysts. The amphiphilic character of these nanohybrids makes them effective in stabilizing emulsions (up to 85 % of total volume) comprising of small droplets (less than 40 μm). Furthermore, these nanohybrids have been used as supports for transition metal particles (palladium and copper) to catalyze reactions at the water/oil interface.

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The properties of 3 nm-diameter silica nanoparticles with different surface chemistry were systematically investigated at the decane-water interface using molecular dynamics simulations. Our results show that the decane-water interfacial tension is not much influenced by the presence of the nanoparticles. The three-phase contact angle increases with nanoparticle surface hydrophobicity.

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Techniques for separating bundles of carbon nanotubes into homogeneous dispersion are still under development, although a few methods have been successful at the laboratory scale. Understanding the effective interactions between carbon nanotubes in the presence of dispersing agents will provide the necessary information to develop better methods and also to refine the existing ones. We present here results from all-atom molecular dynamics simulations for aqueous flavin mononucleotide (FMN), which has been found experimentally to efficiently separate single-walled carbon nanotubes (SWNTs) based on diameter and chirality.

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A simple and quantitative, self-calibrating spectroscopic technique for the determination of the ratio of metallic to semiconducting single-wall carbon nanotubes (SWCNTs) in a bulk sample is presented. The technique is based on the measurement of the electron paramagnetic resonance (EPR) spectrum of the SWCNT sample to which cobalt(II)octaethylporphyrin (CoOEP) probe molecules have been added. This yields signals from both CoOEP molecules on metallic and on semiconducting tubes, which are easily distinguished and accurately characterized in this work.

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