Refine
Has Fulltext
- yes (235)
Year of publication
Document Type
- Postprint (235) (remove)
Keywords
- LIBS (4)
- anomalous diffusion (4)
- living cells (4)
- nanoparticles (4)
- DNA origami (3)
- Diodenlaserspektroskopie (3)
- Fluoreszenz-Resonanz-Energie-Transfer (3)
- Immunoassay (3)
- Kohlendioxid (3)
- Lumineszenz (3)
- biomaterials (3)
- crystal structure (3)
- infection pathway (3)
- ligand (3)
- luminescence (3)
- models (3)
- quantum dots (3)
- shape (3)
- structure elucidation (3)
- surface (3)
- water (3)
- 3D printing (2)
- DNA radiation damage (2)
- Energietransfer (2)
- Europium (2)
- FRET (2)
- Fluorescence spectroscopy (2)
- Isotopenverhältnis (2)
- Juvenile hormone (2)
- Leguminosae (2)
- PCA (2)
- Quantenpunkt (2)
- adsorption (2)
- aqueous-solution (2)
- arsenolipids present (2)
- assemblies (2)
- biodegradable polymers (2)
- biomass (2)
- biomineralization (2)
- calcium phosphate (2)
- carbohydrates (2)
- carbon dioxide (2)
- carbon monoxide (2)
- carbon-dioxide (2)
- carbon-dioxide capture (2)
- cellulose (2)
- chitosan (2)
- cod-liver (2)
- composites (2)
- copolymers (2)
- diode laser spectroscopy (2)
- dye removal (2)
- dynamics (2)
- fatty-acids (2)
- ferroelectricity (2)
- films (2)
- heteroatoms (2)
- hybrid perovskites (2)
- hydrogel (2)
- identification (2)
- in-situ (2)
- inorganic chemistry (2)
- intracellular-transport (2)
- ionic conductivity (2)
- ionic liquid (2)
- ionic liquids (2)
- isomerization (2)
- langevin equation (2)
- low-energy electrons (2)
- manganese (2)
- metal-organic frameworks (2)
- methyl orange (2)
- methylene blue (2)
- mixtures (2)
- molecules (2)
- nanostructures (2)
- phase-transitions (2)
- photoisomerization (2)
- photovoltaic materials (2)
- physiological consequences (2)
- poly(lactic acid) (2)
- polysoaps (2)
- polyzwitterion (2)
- polyzwitterions (2)
- proteins (2)
- random-walks (2)
- reduction (2)
- resonance energy-transfer (2)
- ring-opening polymerization (2)
- salts (2)
- sclerotization (2)
- sensitivity (2)
- simulations (2)
- single-particle tracking (2)
- size (2)
- soil (2)
- sorption (2)
- synthesis (2)
- system (2)
- systems (2)
- visible-light (2)
- water treatment (2)
- zinc (2)
- (S)-Elatadihydrochalcone (1)
- (S)-Lupinifolin 4´-methyl ether (1)
- 1,2-dithiooxalate (1)
- 11-mercaptoundecanoic acid (1)
- 2-Azaspiro[4.5]deca-1-ones (1)
- 2D-LC-MS/MS (1)
- 3-color fret (1)
- 3-mercaptopropionic acid (1)
- 315 nm (1)
- 473 nm (1)
- 946 nm (1)
- AOT bilayer (1)
- ATCUN motif (1)
- Absorption (1)
- Absorptionsspektroskopie (1)
- Acids (1)
- AgI (1)
- Amphiphiles (1)
- Amphiphilic Polymers (1)
- Amphiphilic polymers (1)
- Biological activity (1)
- Biophotonik (1)
- Biosynthesis (1)
- Bodengas (1)
- Bodenschutz (1)
- C-reactive (1)
- Caenorhabditis elegans (1)
- Cd-free (1)
- Cellulose (1)
- Cereals (1)
- Chitinase (1)
- Chitosan (1)
- Cis- and trans-form (1)
- Configuration (1)
- Confocal microscopy (1)
- Conformation (1)
- Corpora allata (1)
- DNA damage response (1)
- DNA repair (1)
- DNA strand breaks (1)
- Derris trifoliata (1)
- Electrochemistry (1)
- Energy Transfer (1)
- Enzyme (1)
- Enzyme inhibitor (1)
- Flavanone (1)
- Fluorescence imaging (1)
- Fluorescent probes (1)
- Fluoreszenzspektroskopie (1)
- Fokker-Planck equations (1)
- Formate (1)
- Fungi (1)
- Förster Resonanz Energie Transfer (1)
- Förster resonance energy transfer (1)
- Förster-Resonanz-Energie-Transfer (1)
- G quadruplexes (1)
- Galactosides (1)
- Glycoconjugates (1)
- Glycopeptides (1)
- Gold nanoparticles (1)
- Grundwasserschutz (1)
- HDAC1 (1)
- Huminstoffe (1)
- Hyalophora cecropia (1)
- Hybrid material (1)
- ITC (1)
- In vitro (1)
- InP (1)
- InPZnS (1)
- Ion mobility spectrometry (1)
- Ionic liquid (1)
- Ionic liquids (1)
- Isotop (1)
- Isotope ratio (1)
- Isotopie (1)
- JH-III-specific carrier protein (1)
- Janus droplets (1)
- Juvenile hormone analogue (1)
- Kinetically controlled nanocrystal growth (1)
- Kohlenmonoxid (1)
- LCPs (1)
- Lactams (1)
- Lanthanoide (1)
- Laser (1)
- Leptinotarsa decemlineata (1)
- Lichtstreuung (1)
- Locust (1)
- Locusta migratoria (1)
- Luminescence (1)
- Lupinifolin (1)
- MALDI-TOF mass spectrometry (1)
- MS (1)
- Micellar polymers (1)
- Modified mycotoxins (1)
- Monolayers (1)
- Multi-method (1)
- Mycotoxins (1)
- N-acetyldopamine (1)
- NIR spectroscopy (1)
- NMR structure (1)
- Nanoparticles (1)
- Nanopartikel (1)
- Nanotriangles (1)
- Neodym-YAG-Laser (1)
- NiTi (1)
- O-methyltransferase (1)
- OTDR (1)
- Oligosaccharides (1)
- Optode (1)
- Orthoptera (1)
- PAH (1)
- PEI coating (1)
- PLA (1)
- PLS regression (1)
- PLSR (1)
- Pesticides (1)
- Pestizid (1)
- Phytopathogens (1)
- Pickering emulsions (1)
- Podanthus mitiqui (1)
- Polyampholytes (1)
- Polymerizable surfactant (1)
- Precipitation (1)
- Prozesskontrolle (1)
- QDs (1)
- Quantum Dot (1)
- Quartz Crystal (1)
- REMPI (1)
- RP-HPLC (1)
- RUNX2 (1)
- Rod-like Polymers (1)
- SAK (1)
- SEM (1)
- SERS (1)
- SERS enhancement factor (1)
- Salts (1)
- Sauerstoff (1)
- Schädlingsbekämpfung (1)
- Seedpods (1)
- Sensorik (1)
- Serum (1)
- Stability of LB Films (1)
- Steroid esters (1)
- Summenparameter (1)
- Synthesis and processing (1)
- Tephrosia elata (1)
- TiO2 nanoparticles (1)
- UVR (1)
- Untersuchung (1)
- X-ray diffraction (1)
- X-ray structure (1)
- [4+2] cycloaddition (1)
- [N]phenylene dyads (1)
- [N]phenylenes (1)
- absorbtion fine-structure (1)
- acceptors (1)
- acid (1)
- acids (1)
- acinar-cells (1)
- acrylic acid esters (1)
- actinide, organic ligand, sorption, cementitious material, concrete, luminescence (1)
- activated carbon (1)
- activated urethane derivatives (1)
- adamantane (1)
- adduct formation (1)
- adenoassociated virus (1)
- air-water-interface (1)
- alignment (1)
- alkynol cycloisomerization (1)
- amorphous carbon (1)
- amorphous polymers (1)
- anchor peptides (1)
- anionic polymerizations (1)
- anti-fouling materials (1)
- antibodies (1)
- antifouling (1)
- antimalarial activity (1)
- aptamers (1)
- aqueous dispersion (1)
- arenediazonium salts (1)
- arsenious acid (1)
- artificial muscles (1)
- arylboronic acids (1)
- aryldiazonium salts (1)
- aspect-ratio (1)
- associating polymers (1)
- atomic force microscopy (1)
- atropisomerism (1)
- attachment (1)
- augmented-wave method (1)
- auxiliary control (1)
- beer (1)
- behavior (1)
- betaine (1)
- binding (1)
- bioanalysis (1)
- biomaterial (1)
- biophotonics (1)
- biorefineries (1)
- bladder-cancer (1)
- block-copolymer (1)
- block-copolymers (1)
- bone tissue engineering (1)
- boronic acid (1)
- brownian-motion (1)
- brushite (1)
- building-blocks (1)
- cadmium-free (1)
- calcium carbonate (1)
- calcium influx (1)
- calcium phosphate hybrid material (1)
- capacity (1)
- carbohydrate derivatives (1)
- carbohydrate esters (1)
- carbohydrate-based oxepines (1)
- carbohydrate‐ based (1)
- carbon dots (1)
- carbonyl-compounds (1)
- carboxyanhydrides (1)
- carcinogen exposure (1)
- catalysts (1)
- catalyzed cross metathesis (1)
- catalyzed redox isomerization (1)
- cationic surfactants (1)
- cell-death (1)
- cement admixtures (1)
- cement hydration (1)
- cementitious material (1)
- chain azobenzene polymers (1)
- chemical-synthesis (1)
- chemoradiation therapy (1)
- chirality (1)
- chromoionophore (1)
- citric acid (1)
- click chemistry (1)
- clusters (1)
- coatings (1)
- cockroach salivary-glands (1)
- coloring agents (1)
- complex (1)
- complexes (1)
- concrete (1)
- configuration (1)
- confocal raman microscopy (1)
- conformation (1)
- conformational-changes (1)
- construction (1)
- continuous-flow (1)
- contrast agents (1)
- controlled-release (1)
- coordination polymer (1)
- copper (1)
- copper complex (1)
- copper(II) (1)
- copper(II) halide salts (1)
- copper-bearing minerals (1)
- covalent organic framework (1)
- crosslinking (1)
- crown compounds (1)
- cryogel (1)
- crystals (1)
- cytoplasm (1)
- cytosine methylation (1)
- damage (1)
- data-storage (1)
- de-novo synthesis (1)
- decay dynamics (1)
- degradation (1)
- delivery (1)
- density functional theory (1)
- diels-alder reaction (1)
- diimine-complexes (1)
- dilute aqueous-solutions (1)
- dimerization of 4-nitrothiophenol (1)
- dip-coating (1)
- discotics (1)
- disordered media (1)
- dissociative electron attachment (1)
- dna coiling (1)
- drug delivery system (1)
- drugs (1)
- dye (1)
- dye adsorption (1)
- dye mixture (1)
- dyes (1)
- dynamic HPLC (1)
- dynamic NMR (1)
- efficient (1)
- electrochemistry (1)
- electrolytes (1)
- electron paramagnetic resonance (1)
- electron-spin resonance (1)
- electron-transfer (1)
- elemental composition (1)
- enantioselectivity (1)
- endosomal escape (1)
- energy storage (1)
- enthalpy-entropy compensation (EEC) (1)
- enzymatic degradation (1)
- enzymatic esterification (1)
- enzyme (1)
- enzyme reactions (1)
- epsilon-caprolactone (1)
- erosion (1)
- escence correlation spectroscopy (1)
- escherichia-coli (1)
- ether methacrylates (1)
- europium (1)
- exchange (1)
- excision-repair (1)
- excitation (1)
- excluded volume (1)
- exposure (1)
- extraction (1)
- fiber Bragg gratings (1)
- fiber actuators (1)
- fiber etching (1)
- fiber-optical sensors (1)
- fine-structure (1)
- fish (1)
- flexibility (1)
- flight search patterns (1)
- fluctuation-dissipation theorem (1)
- fluorescence immunoassay (1)
- fluorescence lifetime (1)
- fluorescence photobleaching recovery (1)
- fluorescence quenching (1)
- fluorescent dyemonomers (1)
- fluorescent dyes (1)
- fluorescent probes (1)
- fluorocarbon polymers (1)
- fluoroimmunoassay (1)
- foam analysis (1)
- folding kinetics (1)
- fourier-transform spectroscopy (1)
- fractional dynamics (1)
- fractional dynamics approach (1)
- frameworks (1)
- fronts (1)
- fulgides (1)
- g-quadruplex (1)
- gas (1)
- gas-phase (1)
- gases (1)
- gaussian processes (1)
- gelatin (1)
- gene-expression (1)
- gene-regulation kinetics (1)
- genomic dna methylation (1)
- gepulster DPSS Laser (1)
- germacrane sesquiterpene lactone (1)
- glass-transition temperature (1)
- glucose oxidation (1)
- gold nanoparticle assembly (1)
- gold nanoparticles (1)
- graphene (1)
- graphite (1)
- green (1)
- green chemistry (1)
- green polymers (1)
- halide-ions (1)
- hela-cells (1)
- hepcidin-25 (1)
- heterocycles (1)
- heterogeneous catalysis (1)
- holmium(III) (1)
- holographic diffraction gratings (1)
- human-cells (1)
- hydraulic oils (1)
- hydrogen (1)
- hydrogen storage (1)
- hydrogenation (1)
- hydrolysis (1)
- hydrophilic polymers (1)
- hydroxyl-functional poly(2-vinyl pyridine) (1)
- hydroyxapatite (1)
- iPLS regression (1)
- imidazolium salts (1)
- immunoassay (1)
- implementation (1)
- in-vitro (1)
- indicators (1)
- induced malignant-transformation (1)
- inhomogeneous-media (1)
- initio molecular-dynamics (1)
- inner surface (1)
- inorganic perovskites (1)
- intercomparison (1)
- intermittent chaotic systems (1)
- intracellular na+ (1)
- intramolecular charge-transfer (1)
- intrinsic microporosity (1)
- ion optodes (1)
- ionogel (1)
- ionogels (1)
- ionophore (1)
- ionothermal synthesis (1)
- isotope (1)
- isotope ratios (1)
- joziknipholones (1)
- juvenile hormone biosynthesis (1)
- labels (1)
- lanthanide luminescence (1)
- lanthanides (1)
- laser induced (1)
- laser-induced breakdown spectroscopy (1)
- lasso (1)
- levy flights (1)
- lifetime microscopy (1)
- ligand exchange (1)
- light (1)
- lignocellulosic biomass (1)
- liquid crystals (1)
- liquid-crystal precursors (1)
- liquid-phase catalysis (1)
- lower critical solution temperature (1)
- lubricants (1)
- magnetic manipulation (1)
- magnetic nanoparticles (1)
- magnetic-properties (1)
- magnetite nanoparticles (1)
- marine oils (1)
- mass spectrometry (1)
- mass-spectrometry (1)
- mechanical properties (1)
- mechanical strength (1)
- mechanical-properties (1)
- membrane (1)
- membranes (1)
- mercaptocarboxylic acids (1)
- mesenchymal stem cells (1)
- metabolites (1)
- metal complex (1)
- metal nanoparticles (1)
- metal peptide (1)
- metal species (1)
- metallic nanolattices (1)
- metallopeptide (1)
- metalloprotein (1)
- methylmercury (1)
- methyltransferases dnmt3a (1)
- micelle (1)
- microbalance (1)
- microcontact printing (1)
- microgels (1)
- microporous organic polymers (1)
- microscopy (1)
- microstructure (1)
- mineralization beneath (1)
- minerals (1)
- mixed-matrix membranes (1)
- modulation (1)
- modulus (1)
- molecular dynamics (1)
- molecular oxygen (1)
- molecular rods (1)
- molecular thermometers (1)
- molecular-dynamics (1)
- molecular-mechanisms (1)
- molecular-reorientation (1)
- molecular-structure (1)
- monolayer (1)
- monomer (1)
- monomers (1)
- morphological transformation (1)
- morphology (1)
- multishell (1)
- n-heterocyclic carbenes (1)
- n-isopropylacrylamide (1)
- nanocarriers (1)
- nanoclusters (1)
- nanoflowers (1)
- nanolenses (1)
- nanoparticle dimers (1)
- nanoprisms (1)
- nanorods (1)
- nanostructure fabrication (1)
- nanotriangles (1)
- nanowires (1)
- naphthalenes (1)
- naphthalenophanes (1)
- naphthalimide (1)
- natural products (1)
- negative ions (1)
- neurodegenerative diseases (1)
- neurotoxicity (1)
- nhc (1)
- nickel (1)
- nickel(II) (1)
- nucleation (1)
- nutrients (1)
- o bond formation (1)
- o-quinone isomerase (1)
- oil (1)
- olefin-metathesis (1)
- oligo(ethylene glycol) methacrylate (1)
- oligomeric polydimethylsiloxane (1)
- optical oil sensor (1)
- optical sensing (1)
- optical-properties (1)
- optode (1)
- organic dye pigments (1)
- organic ligand (1)
- organic–inorganic hybrid (1)
- orthophosphates (1)
- oxaloacetic acid (1)
- oxidation (1)
- oxidative stress (1)
- oxygen (1)
- palladium catalyst (1)
- paper (1)
- paramagnetic-resonance (1)
- perfluorocarbon emulsion (1)
- periplaneta-americana (1)
- phase separation (1)
- phase transfer (1)
- phenanthrenes (1)
- phosgene-free synthesis (1)
- photo-dehydro-Diels-Alder reaction (1)
- photochemical synthesis (1)
- photoinduced electron transfer (1)
- photoinduced nonadiabatic dynamics (1)
- photon density wave spectroscopy (1)
- photon-counting statistics (1)
- photonic wires (1)
- photooxidation (1)
- photooxygenation (1)
- photophysics (1)
- pickering emulsion (1)
- poly(ADP-ribose) polymerase-1 (1)
- poly(N-vinylcaprolactam) (1)
- poly(dimethylsiloxane) (1)
- poly(ester amide)s (1)
- poly(ethyleneimine) (1)
- polyamine (1)
- polyammonium salt (1)
- polyampholyte (1)
- polybutadiene (1)
- polycarboxylate (1)
- polycationic monolayer (1)
- polydimethylsiloxane wrinkles (1)
- polymer degradation (1)
- polymeric sensors (1)
- polymerization (1)
- polymersomes (1)
- polypeptide (1)
- polypeptides (1)
- polypropylene yarns (1)
- polysoap (1)
- polysulfabetaine (1)
- polysulfobetaine (1)
- polyzyklische aromatische Kohlenwasserstoffe (1)
- poly‐ ε ‐ caprolactone (1)
- porous carbon (1)
- porous carbon materials (1)
- post-polymerization modification (1)
- precatalysts (1)
- precision agriculture (1)
- pressure (1)
- process analytical technology (1)
- protein binding (1)
- protein interactions (1)
- protein-kinase inhibitors (1)
- proximal soil sensing (1)
- pulsed DPSS laser (1)
- purity (1)
- quinone (1)
- quinone methide (1)
- racemization (1)
- radicals (1)
- rare earth elements (1)
- rat (1)
- ratiometric (1)
- ray absorption-spectroscopy (1)
- reactivity (1)
- recognition (1)
- recombinant protein (1)
- redox chemistry (1)
- reference material (1)
- repair (1)
- resistive heating (1)
- resonance energy-tansfer (1)
- resonant formation (1)
- responsive polymers (1)
- reversible shape-memory actuator (1)
- review (1)
- ring-closing metathesis (1)
- ring-closure (1)
- roughness (1)
- rp-hplc (1)
- ruthenium carbene (1)
- samples (1)
- scale (1)
- selectivity (1)
- semiempirical methods (1)
- sensors (1)
- separation (1)
- sequence dependence (1)
- sers (1)
- shape‐memory polymer actuators (1)
- silver (1)
- silver nanowires (1)
- sinefungin (1)
- single-molecule analysis (1)
- single-strand breaks (1)
- singlet oxygen (1)
- sodium (1)
- sodium green (1)
- sodium hydroxide etching (1)
- soft robotics (1)
- soil gas (1)
- soil nutrients (1)
- solubility (1)
- solubilization (1)
- solvatochromic fluorophore (1)
- solvatochromism (1)
- solvent (1)
- spacer (1)
- spatial-organization (1)
- speciation (1)
- spectra (1)
- spectroscopy (1)
- spent coffee (1)
- spherical polyelectrolyte brushes (1)
- spider silk (1)
- spiked and crumble gold nanotriangles (1)
- square planar (1)
- stability (1)
- stannous octoate (1)
- state (1)
- states (1)
- step (1)
- stereoselective-synthesis (1)
- stereoselectivity (1)
- stokes shift (1)
- strand breakage (1)
- structural-characterization (1)
- substituted stilbenes (1)
- sulfobetain (1)
- sulfoxides (1)
- sulfur (1)
- supported gold (1)
- surface functionalization (1)
- surface modification (1)
- surface-plasmon resonance (1)
- surfaces (1)
- sustainability (1)
- switches (1)
- sättigbarer Absorber (1)
- tandem solar cells (1)
- tannic acid (1)
- tanning agents (1)
- temperature (1)
- temperature phase (1)
- tetrabromidocuprate(II) (1)
- tetrachlorocuprate(II) salts (1)
- thermal properties (1)
- thermo-responsive polymers (1)
- thermochemistry (1)
- thermodynamics (1)
- thermometer (1)
- thermoresponsive polymers (1)
- thimerosal (1)
- thin-films (1)
- thio-dimethylarsinic acid (1)
- tight-binding (1)
- time random-walks (1)
- to-coil transition (1)
- trafficking (1)
- trans-stilbenes (1)
- transformation (1)
- transition (1)
- transition-metal-complexes (1)
- triangular-[4] phenylene (1)
- trivalent (1)
- tunable diode laser (TDL) (1)
- tyrosinase; o-quinones (1)
- ultra-fast laser inscription (1)
- ultrafast (1)
- undulated (1)
- uranium (VI) (1)
- ventricular myocytes (1)
- vesicles (1)
- viologen (1)
- vitro toxicological characterization (1)
- wavelength (1)
- weak ergodicity breaking (1)
- wettability (1)
- wrinkled stamps (1)
- zeolitic imidazolate frameworks (1)
- zwitterionic group (1)
- β-Hydroxydihydrochalcone (1)
Institute
- Institut für Chemie (235) (remove)
The retention of actinides in different oxidation states (An(X), X = III, IV, VI) by a calcium-silicate-hydrate (C-S-H) phase with a Ca/Si (C/S) ratio of 0.8 was investigated in the presence of gluconate (GLU). The actinides considered were Am(III), Th(IV), Pu(IV), and U(VI). Eu(III) was investigated as chemical analogue for Am(III) and Cm(III). In addition to the ternary systems An(X)/GLU/C-S-H, also binary systems An(X)/C-S-H, GLU/C-S-H, and An(X)/GLU were studied. Complementary analytical techniques were applied to address the different specific aspects of the binary and ternary systems. Time-resolved laser-induced luminescence spectroscopy (TRLFS) was applied in combination with parallel factor analysis (PARAFAC) to identify retained species and to monitor species-selective sorption kinetics. ¹³C and ²⁹Si magic-angle-spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy and X-ray photoelectron spectroscopy (XPS) were applied to determine the bulk structure and the composition of the C-S-H surface, respectively, in the absence and presence of GLU. The interaction of Th(IV) with GLU in different electrolytes was studied by capillary electrophoresis-inductively coupled plasma mass spectrometry (CE-ICP-MS). The influence of GLU on An(X) retention was investigated for a large concentration range up to 10⁻² M. The results showed that GLU had little to no effect on the overall An(X) retention by C-S-H with C/S of 0.8, regardless of the oxidation state of the actinides. For Eu(III), the TRLFS investigations additionally implied the formation of a Eu(III)-bearing precipitate with dissolved constituents of the C-S-H phase, which becomes structurally altered by the presence of GLU. For U(VI) sorption on the C-S-H phase, only a small influence of GLU could be established in the luminescence spectroscopic investigations, and no precipitation of U(VI)-containing secondary phases could be identified.
Its properties make copper one of the world’s most important functional metals. Numerous megatrends are increasing the demand for copper. This requires the prospection and exploration of new deposits, as well as the monitoring of copper quality in the various production steps. A promising technique to perform these tasks is Laser Induced Breakdown Spectroscopy (LIBS). Its unique feature, among others, is the ability to measure on site without sample collection and preparation. In this work, copper-bearing minerals from two different deposits are studied. The first set of field samples come from a volcanogenic massive sulfide (VMS) deposit, the second part from a stratiform sedimentary copper (SSC) deposit. Different approaches are used to analyze the data. First, univariate regression (UVR) is used. However, due to the strong influence of matrix effects, this is not suitable for the quantitative analysis of copper grades. Second, the multivariate method of partial least squares regression (PLSR) is used, which is more suitable for quantification. In addition, the effects of the surrounding matrices on the LIBS data are characterized by principal component analysis (PCA), alternative regression methods to PLSR are tested and the PLSR calibration is validated using field samples.
A new solid-state material, N-butyl pyridinium diiodido argentate(I), is synthesized using a simple and effective one-pot approach. In the solid state, the compound exhibits 1D ([AgI2](-))(n) chains that are stabilized by the N-butyl pyridinium cation. The 1D structure is further manifested by the formation of long, needle-like crystals, as revealed from electron microscopy. As the general composition is derived from metal halide-based ionic liquids, the compound has a low melting point of 100-101 degrees C, as confirmed by differential scanning calorimetry. Most importantly, the compound has a conductivity of 10(-6) S cm(-1) at room temperature. At higher temperatures the conductivity increases and reaches to 10(-4 )S cm(-1) at 70 degrees C. In contrast to AgI, however, the current material has a highly anisotropic 1D arrangement of the ionic domains. This provides direct and tuneable access to fast and anisotropic ionic conduction. The material is thus a significant step forward beyond current ion conductors and a highly promising prototype for the rational design of highly conductive ionic solid-state conductors for battery or solar cell applications.
Eight d-metal-containing N-butylpyridinium ionic liquids (ILs) with the nominal composition (C4Py)2[Ni0.5M0.5Cl4] or (C4Py)2[Zn0.5M0.5Cl4] (M = Cu, Co, Mn, Ni, Zn; C4Py = N-butylpyridinium) were synthesized, characterized, and investigated for their optical properties. Single crystal and powder X-ray analysis shows that the compounds are isostructural to existing examples based on other d-metal ions. Inductively coupled plasma optical emission spectroscopy measurements confirm that the metal/metal ratio is around 50 : 50. UV-Vis spectroscopy shows that the optical absorption can be tuned by selection of the constituent metals. Moreover, the compounds can act as an optical sensor for the detection of gases such as ammonia as demonstrated via a simple prototype setup.
Stereoselective [4+2] Cycloaddition of Singlet Oxygen to Naphthalenes Controlled by Carbohydrates
(2021)
Stereoselective reactions of singlet oxygen are of current interest. Since enantioselective photooxygenations have not been realized efficiently, auxiliary control is an attractive alternative. However, the obtained peroxides are often too labile for isolation or further transformations into enantiomerically pure products. Herein, we describe the oxidation of naphthalenes by singlet oxygen, where the face selectivity is controlled by carbohydrates for the first time. The synthesis of the precursors is easily achieved starting from naphthoquinone and a protected glucose derivative in only two steps. Photooxygenations proceed smoothly at low temperature, and we detected the corresponding endoperoxides as sole products by NMR. They are labile and can thermally react back to the parent naphthalenes and singlet oxygen. However, we could isolate and characterize two enantiomerically pure peroxides, which are sufficiently stable at room temperature. An interesting influence of substituents on the stereoselectivities of the photooxygenations has been found, ranging from 51:49 to up to 91:9 dr (diastereomeric ratio). We explain this by a hindered rotation of the carbohydrate substituents, substantiated by a combination of NOESY measurements and theoretical calculations. Finally, we could transfer the chiral information from a pure endoperoxide to an epoxide, which was isolated after cleavage of the sugar chiral auxiliary in enantiomerically pure form.
Janus droplets were prepared by vortex mixing of three non-mixable liquids, i.e., olive oil, silicone oil and water, in the presence of gold nanoparticles (AuNPs) in the aqueous phase and magnetite nanoparticles (MNPs) in the olive oil. The resulting Pickering emulsions were stabilized by a red-colored AuNP layer at the olive oil/water interface and MNPs at the oil/oil interface. The core–shell droplets can be stimulated by an external magnetic field. Surprisingly, an inner rotation of the silicon droplet is observed when MNPs are fixed at the inner silicon droplet interface. This is the first example of a controlled movement of the inner parts of complex double emulsions by magnetic manipulation via interfacially confined magnetic nanoparticles.
The numerous applications of rare earth elements (REE) has lead to a growing global demand and to the search for new REE deposits. One promising technique for exploration of these deposits is laser-induced breakdown spectroscopy (LIBS). Among a number of advantages of the technique is the possibility to perform on-site measurements without sample preparation. Since the exploration of a deposit is based on the analysis of various geological compartments of the surrounding area, REE-bearing rock and soil samples were analyzed in this work. The field samples are from three European REE deposits in Sweden and Norway. The focus is on the REE cerium, lanthanum, neodymium and yttrium. Two different approaches of data analysis were used for the evaluation. The first approach is univariate regression (UVR). While this approach was successful for the analysis of synthetic REE samples, the quantitative analysis of field samples from different sites was influenced by matrix effects. Principal component analysis (PCA) can be used to determine the origin of the samples from the three deposits. The second approach is based on multivariate regression methods, in particular interval PLS (iPLS) regression. In comparison to UVR, this method is better suited for the determination of REE contents in heterogeneous field samples. View Full-Text
Effects of manganese on genomic integrity in the multicellular model organism Caenorhabditis elegans
(2021)
Although manganese (Mn) is an essential trace element, overexposure is associated with Mn-induced toxicity and neurological dysfunction. Even though Mn-induced oxidative stress is discussed extensively, neither the underlying mechanisms of the potential consequences of Mn-induced oxidative stress on DNA damage and DNA repair, nor the possibly resulting toxicity are characterized yet. In this study, we use the model organism Caenorhabditis elegans to investigate the mode of action of Mn toxicity, focusing on genomic integrity by means of DNA damage and DNA damage response. Experiments were conducted to analyze Mn bioavailability, lethality, and induction of DNA damage. Different deletion mutant strains were then used to investigate the role of base excision repair (BER) and dePARylation (DNA damage response) proteins in Mn-induced toxicity. The results indicate a dose- and time-dependent uptake of Mn, resulting in increased lethality. Excessive exposure to Mn decreases genomic integrity and activates BER. Altogether, this study characterizes the consequences of Mn exposure on genomic integrity and therefore broadens the molecular understanding of pathways underlying Mn-induced toxicity. Additionally, studying the basal poly(ADP-ribosylation) (PARylation) of worms lacking poly(ADP-ribose) glycohydrolase (PARG) parg-1 or parg-2 (two orthologue of PARG), indicates that parg-1 accounts for most of the glycohydrolase activity in worms.
In this contribution the dissociative electron attachment to metabolites found in aerobic organisms, namely oxaloacetic and citric acids, was studied both experimentally by means of a crossed-beam setup and theoretically through density functional theory calculations. Prominent negative ion resonances from both compounds are observed peaking below 0.5 eV resulting in intense formation of fragment anions associated with a decomposition of the carboxyl groups. In addition, resonances at higher energies (3–9 eV) are observed exclusively from the decomposition of the oxaloacetic acid. These fragments are generated with considerably smaller intensities. The striking findings of our calculations indicate the different mechanism by which the near 0 eV electron is trapped by the precursor molecule to form the transitory negative ion prior to dissociation. For the oxaloacetic acid, the transitory anion arises from the capture of the electron directly into some valence states, while, for the citric acid, dipole- or multipole-bound states mediate the transition into the valence states. What is also of high importance is that both compounds while undergoing DEA reactions generate highly reactive neutral species that can lead to severe cell damage in a biological environment.
New cryogels for selective dye removal from aqueous solution were prepared by free radical polymerization from the highly water-soluble crosslinker N,N,N’,N’-tetramethyl-N,N’-bis(2-ethylmethacrylate)-propyl-1,3-diammonium dibromide and the sulfobetaine monomer 2-(N-3-sulfopropyl-N,N-dimethyl ammonium)ethyl methacrylate. The resulting white and opaque cryogels have micrometer sized pores with a smaller substructure. They adsorb methyl orange (MO) but not methylene blue (MB) from aqueous solution. Mixtures of MO and MB can be separated through selective adsorption of the MO to the cryogels while the MB remains in solution. The resulting cryogels are thus candidates for the removal of hazardous organic substances, as exemplified by MO and MB, from water. Clearly, it is possible that the cryogels are also potentially interesting for removal of other compounds such as pharmaceuticals or pesticides, but this must be investigated further.
Carbon Adsorbents from Spent Coffee for Removal of
Methylene Blue and Methyl Orange from Water
(2021)
Activated carbons (ACs) were prepared from dried spent coffee (SCD), a biological waste product, to produce adsorbents for methylene blue (MB) and methyl orange (MO) from aqueous solution. Pre-pyrolysis activation of SCD was achieved via treatment of the SCD with aqueous sodium hydroxide solutions at 90 °C. Pyrolysis of the pretreated SCD at 500 °C for 1 h produced powders with typical characteristics of AC suitable and effective for dye adsorption. As an alternative to the rather harsh base treatment, calcium carbonate powder, a very common and abundant resource, was also studied as an activator. Mixtures of SCD and CaCO3 (1:1 w/w) yielded effective ACs for MO and MB removal upon pyrolysis needing only small amounts of AC to clear the solutions. A selectivity of the adsorption process toward anionic (MO) or cationic (MB) dyes was not observed.
Mycotoxins and pesticides regularly co-occur in agricultural products worldwide. Thus, humans can be exposed to both toxic contaminants and pesticides simultaneously, and multi-methods assessing the occurrence of various food contaminants and residues in a single method are necessary. A two-dimensional high performance liquid chromatography tandem mass spectrometry method for the analysis of 40 (modified) mycotoxins, two plant growth regulators, two tropane alkaloids, and 334 pesticides in cereals was developed. After an acetonitrile/water/formic acid (79:20:1, v/v/v) multi-analyte extraction procedure, extracts were injected into the two-dimensional setup, and an online clean-up was performed. The method was validated according to Commission Decision (EC) no. 657/2002 and document N° SANTE/12682/2019. Good linearity (R2 > 0.96), recovery data between 70-120%, repeatability and reproducibility values < 20%, and expanded measurement uncertainties < 50% were obtained for a wide range of analytes, including very polar substances like deoxynivalenol-3-glucoside and methamidophos. However, results for fumonisins, zearalenone-14,16-disulfate, acid-labile pesticides, and carbamates were unsatisfying. Limits of quantification meeting maximum (residue) limits were achieved for most analytes. Matrix effects varied highly (−85 to +1574%) and were mainly observed for analytes eluting in the first dimension and early-eluting analytes in the second dimension. The application of the method demonstrated the co-occurrence of different types of cereals with 28 toxins and pesticides. Overall, 86% of the samples showed positive findings with at least one mycotoxin, plant growth regulator, or pesticide.
Radical reactions have found many applications in carbohydrate chemistry, especially in the construction of carbon–carbon bonds. The formation of carbon–heteroatom bonds has been less intensively studied. This mini-review will summarize the efforts to add heteroatom radicals to unsaturated carbohydrates like endo-glycals. Starting from early examples, developed more than 50 years ago, the importance of such reactions for carbohydrate chemistry and recent applications will be discussed. After a short introduction, the mini-review is divided in sub-chapters according to the heteroatoms halogen, nitrogen, phosphorus, and sulfur. The mechanisms of radical generation by chemical or photochemical processes and the subsequent reactions of the radicals at the 1-position will be discussed. This mini-review cannot cover all aspects of heteroatom-centered radicals in carbohydrate chemistry, but should provide an overview of the various strategies and future perspectives
Nanoporous carbon materials (NCMs) provide the "function" of high specific surface area and thus have large interface area for interactions with surrounding species, which is of particular importance in applications related to adsorption processes. The strength and mechanism of adsorption depend on the pore architecture of the NCMs. In addition, chemical functionalization can be used to induce changes of electron density and/or electron density distribution in the pore walls, thus further modifying the interactions between carbons and guest species. Typical approaches for functionalization of nanoporous materials with regular atomic construction like porous silica, metal-organic frameworks, or zeolites, cannot be applied to NCMs due to their less defined local atomic construction and abundant defects. Therefore, synthetic strategies that offer a higher degree of control over the process of functionalization are needed. Synthetic approaches for covalent functionalization of NCMs, that is, for the incorporation of heteroatoms into the carbon backbone, are critically reviewed with a special focus on strategies following the concept "from molecules to materials." Approaches for coordinative functionalization with metallic species, and the functionalization by nanocomposite formation between pristine carbon materials and heteroatom-containing carbons, are introduced as well. Particular focus is given to the influences of these functionalizations in adsorption-related applications.
A surface modification of ultraflat gold nanotriangles (AuNTs) with different shaped nanoparticles is of special relevance for surface-enhanced Raman scattering (SERS) and the photo-catalytic activity of plasmonic substrates. Therefore, different approaches are used to verify the flat platelet morphology of the AuNTs by oriented overgrowth with metal nanoparticles. The most important part for the morphological transformation of the AuNTs is the coating layer, containing surfactants or polymers. By using well established AuNTs stabilized by a dioctyl sodium sulfosuccinate (AOT) bilayer, different strategies of surface modification with noble metal nanoparticles are possible. On the one hand undulated superstructures were synthesized by in situ growth of hemispherical gold nanoparticles in the polyethyleneimine (PEI)-coated AOT bilayer of the AuNTs. On the other hand spiked AuNTs were obtained by a direct reduction of Au³⁺ ions in the AOT double layer in presence of silver ions and ascorbic acid as reducing agent. Additionally, crumble topping of the smooth AuNTs can be realized after an exchange of the AOT bilayer by hyaluronic acid, followed by a silver-ion mediated reduction with ascorbic acid. Furthermore, a decoration with silver nanoparticles after coating the AOT bilayer with the cationic surfactant benzylhexadecyldimethylammonium chloride (BDAC) can be realized. In that case the ultraviolet (UV)-absorption of the undulated Au@Ag nanoplatelets can be tuned depending on the degree of decoration with silver nanoparticles. Comparing the Raman scattering data for the plasmon driven dimerization of 4-nitrothiophenol (4-NTP) to 4,4′-dimercaptoazobenzene (DMAB) one can conclude that the most important effect of surface modification with a 75 times higher enhancement factor in SERS experiments becomes available by decoration with gold spikes.
A thermodynamic study of the adsorption of Human Serum Albumin (HSA) onto spherical polyelectrolyte brushes (SPBs) by isothermal titration calorimetry (ITC) is presented. The SPBs are composed of a solid polystyrene core bearing long chains of poly(acrylic acid). ITC measurements done at different temperatures and ionic strengths lead to a full set of thermodynamicbinding constants together with the enthalpies and entropies of binding. The adsorption of HSA onto SPBs is described with a two-step model. The free energy of binding Delta Gb depends only weakly on temperature because of a marked compensation of enthalpy by entropy. Studies of the adsorbed HSA by Fourier transform infrared spectroscopy (FT-IR) demonstrate no significant disturbance in the secondary structure of the protein. The quantitative analysis demonstrates that counterion release is the major driving force for adsorption in a process where proteins become multivalent counterions of the polyelectrolyte chains upon adsorption. A comparison with the analysis of other sets of data related to the binding of HSA to polyelectrolytes demonstrates that the cancellation of enthalpy and entropy is a general phenomenon that always accompanies the binding of proteins to polyelectrolytes dominated by counterion release.
The DNA in living cells can be effectively damaged by high-energy radiation, which can lead to cell death. Through the ionization of water molecules, highly reactive secondary species such as low-energy electrons (LEEs) with the most probable energy around 10 eV are generated, which are able to induce DNA strand breaks via dissociative electron attachment. Absolute DNA strand break cross sections of specific DNA sequences can be efficiently determined using DNA origami nanostructures as platforms exposing the target sequences towards LEEs. In this paper, we systematically study the effect of the oligonucleotide length on the strand break cross section at various irradiation energies. The present work focuses on poly-adenine sequences (d(A₄), d(A₈), d(A₁₂), d(A₁₆), and d(A₂₀)) irradiated with 5.0, 7.0, 8.4, and 10 eV electrons. Independent of the DNA length, the strand break cross section shows a maximum around 7.0 eV electron energy for all investigated oligonucleotides confirming that strand breakage occurs through the initial formation of negative ion resonances. When going from d(A₄) to d(A₁₆), the strand break cross section increases with oligonucleotide length, but only at 7.0 and 8.4 eV, i.e., close to the maximum of the negative ion resonance, the increase in the strand break cross section with the length is similar to the increase of an estimated geometrical cross section. For d(A₂₀), a markedly lower DNA strand break cross section is observed for all electron energies, which is tentatively ascribed to a conformational change of the dA₂₀ sequence. The results indicate that, although there is a general length dependence of strand break cross sections, individual nucleotides do not contribute independently of the absolute strand break cross section of the whole DNA strand. The absolute quantification of sequence specific strand breaks will help develop a more accurate molecular level understanding of radiation induced DNA damage, which can then be used for optimized risk estimates in cancer radiation therapy.
The article describes a systematic investigation of the effects of an aqueous NaOH treatment of 3D printed poly(lactic acid) (PLA) scaffolds for surface activation. The PLA surface undergoes several morphology changes and after an initial surface roughening, the surface becomes smoother again before the material dissolves. Erosion rates and surface morphologies can be controlled by the treatment. At the same time, the bulk mechanical properties of the treated materials remain unaltered. This indicates that NaOH treatment of 3D printed PLA scaffolds is a simple, yet viable strategy for surface activation without compromising the mechanical stability of PLA scaffolds.
Highly luminescent indium phosphide zinc sulfide (InPZnS) quantum dots (QDs), with zinc selenide/zinc sulfide (ZnSe/ZnS) shells, were synthesized. The QDs were modified via a post-synthetic ligand exchange reaction with 3-mercaptopropionic acid (MPA) and 11-mercaptoundecanoic acid (MUA) in different MPA:MUA ratios, making this study the first investigation into the effects of mixed ligand shells on InPZnS QDs. Moreover, this article also describes an optimized method for the correlation of the QD size vs. optical absorption of the QDs. Upon ligand exchange, the QDs can be dispersed in water. Longer ligands (MUA) provide more stable dispersions than short-chain ligands. Thicker ZnSe/ZnS shells provide a better photoluminescence quantum yield (PLQY) and higher emission stability upon ligand exchange. Both the ligand exchange and the optical properties are highly reproducible between different QD batches. Before dialysis, QDs with a ZnS shell thickness of ~4.9 monolayers (ML), stabilized with a mixed MPA:MUA (mixing ratio of 1:10), showed the highest PLQY, at ~45%. After dialysis, QDs with a ZnS shell thickness of ~4.9 ML, stabilized with a mixed MPA:MUA and a ratio of 1:10 and 1:100, showed the highest PLQYs, of ~41%. The dispersions were stable up to 44 days at ambient conditions and in the dark. After 44 days, QDs with a ZnS shell thickness of ~4.9 ML, stabilized with only MUA, showed the highest PLQY, of ~34%.
Luminescent Ionogels with Excellent Transparency, High Mechanical Strength, and High Conductivity
(2020)
The paper describes a new kind of ionogel with both good mechanical strength and high conductivity synthesized by confining the ionic liquid (IL) 1-butyl-3-methylimidazolium bis(trifluoromethane sulfonyl)imide ([Bmim][NTf₂]) within an organic–inorganic hybrid host. The organic–inorganic host network was synthesized by the reaction of methyltrimethoxysilane (MTMS), tetraethoxysilane (TEOS), and methyl methacrylate (MMA) in the presence of a coupling agent, offering the good mechanical strength and rapid shape recovery of the final products. The silane coupling agent 3-methacryloxypropyltrimethoxysilane (KH-570) plays an important role in improving the mechanical strength of the inorganic–organic hybrid, because it covalently connected the organic component MMA and the inorganic component SiO₂. Both the thermal stability and mechanical strength of the ionogel significantly increased by the addition of IL. The immobilization of [Bmim][NTf₂] within the ionogel provided the final ionogel with an ionic conductivity as high as ca. 0.04 S cm⁻¹ at 50 °C. Moreover, the hybrid ionogel can be modified with organosilica-modified carbon dots within the network to yield a transparent and flexible ionogel with strong excitation-dependent emission between 400 and 800 nm. The approach is, therefore, a blueprint for the construction of next-generation multifunctional ionogels.