118 research outputs found
Photocatalytic applications with CdSâąblock copolymer/exfoliated graphene nanoensembles: Hydrogen generation and degradation of Rhodamine B
Amphiphilic block copolymer poly (isoprene-b-acrylic acid) (PI-b-PAA) stabilized exfoliated graphene in water and allowed the immobilization of semiconductor CdS nanoparticles forming CdSâąPI-b-PAA/graphene. Characterization with HR-TEM and EDX justified the success of preparation and revealed the presence of spherical CdS. Moreover, UV-Vis and photoluminescence assays suggested that electronic interactions within CdSâąPI-b-PAA/graphene exist as evidenced by the significant quenching of the characteristic emission of CdS by exfoliated graphene. Photoillumination of CdSâąPI-b-PAA/graphene, in the presence of ammonium formate as quencher for the photogenerated holes, resulted on the generation of hydrogen by water splitting, monitored by the reduction of 4-nitroaniline to benzene-1,4-diamine (> 80±4% at 20 min; 100% at 24 min), much faster and efficient as compared when reference CdSâąPI-b-PAA was used as photocatalyst (< 30±3% at 20 min; 100% at 240 min). Moreover, Rhodamine B was photocatalytically degraded by CdSâąPI-b-PAA/graphene, with fast kinetics under visible light illumination in the presence of air. The enhancement of both photocatalytic processes by CdSâąPI-b-PAA/graphene was rationalized in terms of effective separation of holesâelectrons, contrary to reference CdSâąPI-b-PAA, in which rapid recombination of the holeâelectron pair is inevitable due to the absence of exfoliated graphene as suitable electron acceptor
Zinc PhthalocyanineâGraphene Hybrid Material for Energy Conversion: Synthesis, Characterization, Photophysics and Photoelectrochemical Cell Preparation
Graphene exfoliation upon tip sonication in o-ÂâDCB was accomplished. Then, covalent grafting of (2-Ââ aminoethoxy)(tri-Ââtert-Ââbutyl) zinc phthalocyanine (ZnPc), to exfoliated graphene sheets was achieved. The newly formed ZnPc-Ââgraphene hybrid material was found soluble in common organic solvents without any precipitation for several weeks. Application of diverse spectroscopic techniques verified the successful formation of ZnPc-Ââgraphene hybrid materi-Ââ al, while thermogravimetric analysis revealed the amount of ZnPc loading onto graphene. Microscopy analysis based on AFM and TEM was applied to probe the morphological characteristics and to investigate the exfoliation of graphene sheets. Efficient fluorescence quenching of ZnPc in the ZnPc-Ââgraphene hybrid material suggested that photoinduced events occur from the photoexcited ZnPc to exfoliated graphene. The dynamics of the photoinduced electron transfer was
evaluated by femtosecond transient absorption spectroscopy, thus, revealing the formation of transient species such as ZnPc+ yielding the charge-Ââseparated state ZnPcâą+âgrapheneâąâ. Finally, the ZnPc-Ââgraphene hybrid material was integrated into a photoactive electrode of an optical transparent electrode (OTE) cast with nanostructured SnO2 films (OTE/SnO2), which exhibited sta le and reproducible photocurrent responses and the incident photon-Ââto-Ââcurrent conversion efficien-Ââ cy was determine
Enhanced NH3-Sensitivity of Reduced Graphene Oxide Modified by Tetra-α-Iso-Pentyloxymetallophthalocyanine Derivatives
The complex genetic landscape of familial MDS and AML reveals pathogenic germline variants.
The inclusion of familial myeloid malignancies as a separate disease entity in the revised WHO classification has renewed efforts to improve the recognition and management of this group of at risk individuals. Here we report a cohort of 86 acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) families with 49 harboring germline variants in 16 previously defined loci (57%). Whole exome sequencing in a further 37 uncharacterized families (43%) allowed us to rationalize 65 new candidate loci, including genes mutated in rare hematological syndromes (ADA, GP6, IL17RA, PRF1 and SEC23B), reported in prior MDS/AML or inherited bone marrow failure series (DNAH9, NAPRT1 and SH2B3) or variants at novel loci (DHX34) that appear specific to inherited forms of myeloid malignancies. Altogether, our series of MDS/AML families offer novel insights into the etiology of myeloid malignancies and provide a framework to prioritize variants for inclusion into routine diagnostics and patient management
Photoluminescence as Complementary Evidence for Short-Range Order in Ionic Silica Nanoparticle Networks
Breakdown into nanoscale of graphene oxide: Confined hot spot atomic reduction and fragmentation
Nano-graphene oxide (nano-GO) is a new class of carbon based materials being proposed for biomedical applications due to its small size, intrinsic optical properties, large specific surface area, and easy to functionalize. To fully exploit nano-GO properties, a reproducible method for its production is of utmost importance. Herein we report, the study of the sequential fracture of GO sheets onto nano-GO with controllable lateral width, by a simple, and reproducible method based on a mechanism that we describe as a confined hot spot atomic fragmentation/reduction of GO promoted by ultrasonication. The chemical and structural changes on GO structure during the breakage were monitored by XPS, FTIR, Raman and HRTEM. We found that GO sheets starts breaking from the defects region and in a second phase through the disruption of carbon bonds while still maintaining crystalline carbon domains. The breaking of GO is accompanied by its own reduction, essentially by the elimination of carboxylic and carbonyl functional groups. Photoluminescence and photothermal studies using this nano-GO are also presented highlighting the potential of this nanomaterial as a unique imaging/therapy platform
ARTICLE IN PRESS G Model Aryl-derivatized, water-soluble functionalized carbon nanotubes for biomedical applications
a b s t r a c t The functionalization of very-thin multi-walled carbon nanotubes (VT-MWNTs) with an aniline derivative, via the protocol of in situ generated aryl diazonium salts results, upon acidic deprotection of the terminal BOC group, on the formation of the water-soluble positively charged ammonium functionalized VT-MWNTs-NH 3 + material. The new materials have been structurally and morphologically characterized by infra-red (ATR-IR) spectroscopy and transmission electron microscopy (TEM). The quantitative calculation of the grafted aryl units onto the skeleton of VT-MWNTs has been estimated by thermogravimetric analysis (TGA), while the quantitative Kaiser test showed the amine group loaded onto VT-MWNTs-NH 3 + material. The aqueous solubility of this material has allowed the performance of some initial toxicological in vitro investigations
Aryl-derivatized, water-soluble functionalized carbon nanotubes for biomedical applications
The functionalization of very-thin multi-walled carbon nanotubes (VT-MWNTs) with an aniline derivative, via the protocol of in situ generated aryl diazonium salts results, upon acidic deprotection of the terminal BOC group, on the formation of the water-soluble positively charged ammonium functionalized VT-MWNTs-NH3+ material. The new materials have been structurally and morphologically characterized by infra-red (ATR-IR) spectroscopy and transmission electron microscopy (TEM). The quantitative calculation of the grafted aryl units onto the skeleton of VT-MWNTs has been estimated by thermogravimetric analysis (TGA), while the quantitative Kaiser test showed the amine group loaded onto VT-MWNTs-NH3+ material. The aqueous solubility of this material has allowed the performance of some initial toxicological in vitro investigations.</p
Aryl-derivatized, water-soluble functionalized carbon nanotubes for biomedical applications
The functionalization of very-thin multi-walled carbon nanotubes (VT-MWNTs) with an aniline derivative, via the protocol of in situ generated aryl diazonium salts results, upon acidic deprotection of the terminal BOC group, on the formation of the water-soluble positively charged ammonium functionalized VT-MWNTs-NH3+ material. The new materials have been structurally and morphologically characterized by infra-red (ATR-IR) spectroscopy and transmission electron microscopy (TEM). The quantitative calculation of the grafted aryl units onto the skeleton of VT-MWNTs has been estimated by thermogravimetric analysis (TGA), while the quantitative Kaiser test showed the amine group loaded onto VT-MWNTs-NH3+ material. The aqueous solubility of this material has allowed the performance of some initial toxicological in vitro investigations. © 2008 Elsevier B.V. All rights reserved
Photocatalytic applications with CdS âą block copolymer/exfoliated graphene nanoensembles: hydrogen generation and degradation of Rhodamine B
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