Search results for "colloid"
showing 10 items of 1288 documents
Self-Assembly-Directed Organization of a Fullerene–Bisporphyrin into Supramolecular Giant Donut Structures for Excited-State Charge Stabilization
2021
Functional materials composed of spontaneously self-assembled electron donor and acceptor entities capable of generating long-lived charge-separated states upon photoillumination are in great demand as they are key in building the next generation of light energy harvesting devices. However, creating such well-defined architectures is challenging due to the intricate molecular design, multistep synthesis, and issues associated in demonstrating long-lived electron transfer. In this study, we have accomplished these tasks and report the synthesis of a new fullerene–bis-Zn-porphyrin e-bisadduct by tether-directed functionalization of C60 via a multistep synthetic protocol. Supramolecular oligom…
Experimental studies on the detachment of multi-walled carbon nanotubes by a mobile liquid interface
2017
International audience; Retention and detachment of colloidal particles from surfaces is often considered only in terms of spontaneous chemical dispersion when the surface is already fully submerged. Nevertheless, interfacial processes, where the particles are caught on a mobile liquid contact line by capillary effects are ubiquitous. Theoretical description of such interfacial processes exist for spherical microcolloids, while for anisotropic shapes the literature is limited. Arc-discharge synthesized multiwalled carbon nanotube (MWNT) material contains besides the very anisotropic tubes also irregular amorphous carbon particles (ACP) that both are strongly hydrophobic. As a water–air–soli…
Novel polyaminoacidic copolymers as nonviral gene vectors
2000
Human gene therapy is one of the most promising methods developed in recent years, providing great potential for the treatment of a variety of diseases. Complexes formed between DNA and cationic polymers are attracting increasing attention as novel synthetic vectors for the delivery of genes. We have synthesized polycations with quaternary ammonium groups in their side chains for self-assembly with calf thymus DNA. This paper describes the functionalization of α,β-polyasparthydrazide (PAHy), a synthetic macromolecule having many potential applications in the field of biomedical sciences, with glycidyltrimethylammonuim chloride (GTA) in order to introduce positive charges into their chains. …
Synthese und Eigenschaften molekulareinheitlicher n-Paraffine bis zum C140H282
1972
Die Umsetzung von α,ω-Dihalogenalkanen mit Natrium fuhrt nach anschliesender katalytischer Hydrierung zu einem Paraffingemisch mit diskontinuierlicher Molekulargewichtsverteilung. So enthalt das aus 1.10-Dibromdecan hergestellte Produkt nur Paraffine mit 10, 20, 30 usw. C-Atomen, ein aus 1.20-Dibromeicosan hergestelltes Produkt dagegen nur die Paraffine mit 20, 40, 60 usw. C-Atomen. Diese Paraffingemische wurden gelchromatographisch in die molekulareinheitlichen Verbindungen zerlegt und Paraffine bis C140H282 isoliert. Am Beispiel des C70H142 wurde die Temperaturabhangigkeit der Rontgenkleinwinkelstreuung gemessen. Aus Intensitat und Lage der Langperiodenreflexe liesen sich die Anderungen v…
Model of a six immunoglobulin-like domain fragment of filamin A (16-21) built using residual dipolar couplings.
2012
Filamins are actin-binding proteins that participate in a wide range of cell functions, including cell morphology, locomotion, membrane protein localization, and intracellular signaling. The three filamin isoforms found in humans, filamins A, B, and C, are highly homologous, and their roles are partly complementary. In addition to actin, filamins interact with dozens of other proteins that have roles as membrane receptors and channels, enzymes, signaling intermediates, and transcription factors. Filamins are composed of an N-terminal actin-binding domain and 24 filamin-type immunoglobulin-like domains (FLN) that form tail-to-tail dimers with their C-terminal FLN domain. Many of the filamin …
π-Extended Pyrene-Fused Double [7]Carbohelicene as a Chiral Polycyclic Aromatic Hydrocarbon
2019
A π-extended double [7]carbohelicene 2 with fused pyrene units was synthesized, revealing considerable intra- and intermolecular π–π interactions as confirmed with X-ray crystallography. As compared to the previous double [7]carbohelicene 1, the π-extended homologue 2 demonstrated considerably red-shifted absorption with an onset at 645 nm (1: 550 nm) corresponding to a smaller optical gap of 1.90 eV (1: 2.25 eV). A broad near-infrared emission from 600 to 900 nm with a large Stokes shift of ∼100 nm (2.3 × 103 cm–1) was recorded for 2, implying formation of an intramolecular excimer upon excitation, which was corroborated with femtosecond transient absorption spectroscopy. Moreover, 2 revea…
Direct Synthesis of Aluminosilicate IWR Zeolite from a Strong Interaction between Zeolite Framework and Organic Template.
2019
A large amount of zeolite structures are still not synthetically available or not available in the form of aluminosilicate currently. Despite significant progress in the development of predictive concepts for zeolite synthesis, accessing some of these new materials is still challenging. One example is the IWR structure as well. Despite successful synthesis of Ge-based IWR zeolites, direct synthesis of aluminosilicate IWR zeolite is still not successful. In this report we show how a suitable organic structure directing agent (OSDA), through modeling of an OSDA/zeolite cage interaction, could access directly the aluminum-containing IWR structure (denoted as COE-6), which might allow access to…
Ultrafast internal conversion of excited cytosine via the lowest pipi electronic singlet state.
2003
Computational evidence at the CASPT2 level supports that the lowest excited state pipi* contributes to the S1/S0 crossing responsible for the ultrafast decay of singlet excited cytosine. The computed radiative lifetime, 33 ns, is consistent with the experimentally derived value, 40 ns. The nOpi* state does not play a direct role in the rapid repopulation of the ground state; it is involved in a S2/S1 crossing. Alternative mechanisms through excited states pisigma* or nNpi* are not competitive in cytosine.
Glycopeptide-functionalized gold nanoparticles for antibody induction against the tumor associated mucin-1 glycoprotein
2015
We report the preparation of gold nanoparticle (AuNP)-based vaccine candidates against the tumor-associated form of the mucin-1 (MUC1) glycoprotein. Chimeric peptides, consisting of a glycopeptide sequence derived from MUC1 and the T-cell epitope P30 sequence were immobilized on PEGylated AuNPs and the ability to induce selective antibodies in vivo was investigated. After immunization, mice showed significant MHC-II mediated immune responses and their antisera recognized human MCF-7 breast cancer cells. Nanoparticles designed according to this report may become key players in the development of anticancer vaccines.
Eco-scalable baicalin loaded vesicles developed by combining phospholipid with ethanol, glycerol, and propylene glycol to enhance skin permeation and…
2019
Abstract A new class of biocompatible and scalable phospholipid vesicles was developed, aiming at improving the efficacy of baicalin on the skin. Phosphatidylcholine and baicalin (a natural polyphenol) were hydrated in two steps with a mixture of ethanol, glycerol, and propylene glycol at different ratios, and a low amount of water (4%). Hence, water was almost completely replaced by the co-solvents, which were never used before as predominant dispersing medium of phospholipid vesicles. The vesicles appeared three-dimensionally structured, forming a network that conferred a high viscosity to the dispersions. The vesicles were unilamellar, small in size (∼100 nm), and stable during 12 months…