Kamusella S.,TU Dresden |
Klauss H.-H.,TU Dresden |
Thakur G.S.,Indian Institute of Technology Delhi |
Thakur G.S.,Max Planck Institute for Chemical Physics of Solids |
And 11 more authors.
Physical Review B - Condensed Matter and Materials Physics | Year: 2017
We have investigated the magnetic ground state of CuFeAs and CuFeSb by means of Fe57-Mössbauer spectroscopy, muon spin rotation/relaxation (μSR), neutron diffraction, and electronic structure calculations. Both materials share the 111-LiFeAs crystal structure and are closely related to the class of iron-based superconductors. In both materials there is a considerable occupancy of the Cu site by Fe, which leads to ferromagnetic moments, which are magnetically strongly coupled to the regular Fe site magnetism. Our study shows that CuFeAs is close to an antiferromagnetic instability, whereas a ferromagnetic ground state is observed in CuFeSb, supporting theoretical models of anion height driven magnetism. © 2017 American Physical Society.
Merschjann C.,University of Rostock |
Merschjann C.,Free University of Berlin |
Tschierlei S.,University of Rostock |
Tschierlei S.,University of Stuttgart |
And 8 more authors.
Advanced Materials | Year: 2015
Charge transport in polymeric graphitic carbon nitrides is shown to proceed via diffusive hopping of electron and hole polarons with reasonably high mobilities >10-5 cm2 V-1 s-1. The power-law behavior of the ultrafast luminescence decay exhibits that the predominant transport direction is perpendicular to the graphitic polymer sheets, thus complementing 2D materials like graphene. © 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.
Li S.,Emory University |
Sidorov A.N.,Georgia Institute of Technology |
Mehta A.K.,Emory University |
Bisignano A.J.,Emory University |
And 9 more authors.
Biochemistry | Year: 2014
Living cells contain a range of densely phosphorylated surfaces, including phospholipid membranes, ribonucleoproteins, and nucleic acid polymers. Hyperphosphorylated surfaces also accumulate in neurodegenerative diseases as neurofibrillar tangles. We have synthesized and structurally characterized a precisely patterned phosphotyrosine surface and establish this assembly as a surrogate of the neuronal tangles by demonstrating its high-affinity binding to histone H1. This association with nucleic acid binding proteins underscores the role such hyperphosphorylated surfaces may play in disease and opens functional exploration into protein-phosphorylated surface interactions in a wide range of other complex assemblies. © 2014 American Chemical Society.
Fettkenhauer C.,Max Planck Institute of Colloids and Interfaces |
Wang X.,Fuzhou University |
Kailasam K.,TU Berlin |
Kailasam K.,Institute of Nano Science and Technology Institute |
And 2 more authors.
Journal of Materials Chemistry A | Year: 2015
A simple one-step procedure for the preparation of cobalt oxide-carbon nitride composites by carrying out the thermal condensation reaction of carbon nitride precursors in cobalt(ii) chloride-containing salt melts is developed. This method enables us to control the structure of the polymer constituent by the proper selection of the second eutectic component. In this respect, alkali metal chlorides and zinc chloride give rise to poly(triazine imides), while tin(ii) chloride delivers melon-based polymers. The crystallinity of the carbon nitride polymer phase can be influenced by varying the concentration of the precursor in the melt. On the other hand, cobalt oxide loading in the final products can be increased by decreasing the precursor concentration in the melt. The products are highly active photocatalysts for Rhodamine B degradation as exemplified by SnCl2/CoCl2-derived solids, and the water oxidation reaction (WOR). The activity of the products in the WOR is comparable with that of the bench composite photocatalyst prepared by using the three-step procedure that includes the synthesis of Co3O4 nanoparticles as a separate step, thus illustrating the advantages of the developed salt melt assisted approach. © 2015 Royal Society of Chemistry.
Chen Z.,Max Planck Institute of Colloids and Interfaces |
Pronkin S.,CNRS The Institute of Chemistry and Processes for Energy, Environment and Health |
Fellinger T.-P.,Max Planck Institute of Colloids and Interfaces |
Kailasam K.,TU Berlin |
And 10 more authors.
ACS Nano | Year: 2016
Herein, we present an approach to create a hybrid between single-atom-dispersed silver and a carbon nitride polymer. Silver tricyanomethanide (AgTCM) is used as a reactive comonomer during templated carbon nitride synthesis to introduce both negative charges and silver atoms/ions to the system. The successful introduction of the extra electron density under the formation of a delocalized joint electronic system is proven by photoluminescence measurements, X-ray photoelectron spectroscopy investigations, and measurements of surface ζ-potential. At the same time, the principal structure of the carbon nitride network is not disturbed, as shown by solid-state nuclear magnetic resonance spectroscopy and electrochemical impedance spectroscopy analysis. The synthesis also results in an improvement of the visible light absorption and the development of higher surface area in the final products. The atom-dispersed AgTCM-doped carbon nitride shows an enhanced performance in the selective hydrogenation of alkynes in comparison with the performance of other conventional Ag-based materials prepared by spray deposition and impregnation-reduction methods, here exemplified with 1-hexyne. © 2016 American Chemical Society.
Pandya S.,CSIR - Central Electrochemical Research Institute |
Pandya S.,Academy of Scientific and Innovative Research AcSIR |
Verma R.K.,CSIR - Central Electrochemical Research Institute |
Verma R.K.,Institute of Nano Science and Technology Institute |
And 9 more authors.
International Journal for Parasitology: Drugs and Drug Resistance | Year: 2016
We investigated efficacy of nitric oxide (NO) against Leishmania donovani. NO is a mediator of host response to infection, with direct parasiticidal activity in addition to its role in signalling to evoke innate macrophage responses. However, it is short-lived and volatile, and is therefore difficult to introduce into infected cells and maintain inracellular concentrations for meaningful periods of time. We incorporated diethylenetriamine NO adduct (DETA/NO), a prodrug, into poly(lactide-co-glycolide) particles of ~200 nm, with or without amphotericin B (AMB). These particles sustained NO levels in mouse macrophage culture supernatants, generating an area under curve (AUC0.08-24h) of 591.2 ± 95.1 mM × h. Free DETA/NO resulted in NO peaking at 3 h and declining rapidly to yield an AUC of 462.5 ± 193.4. Particles containing AMB and DETA/NO were able to kill ~98% of promastigotes and ~76% of amastigotes in 12 h when tested in vitro. Promastigotes and amastigotes were killed less efficiently by particles containing a single drug- either DETA/NO (~42%, 35%) or AMB (~90%, 50%) alone, or by equivalent concentrations of drugs in solution. In a pre-clinical efficacy study of power >0.95 in the hamster model, DETA/NO particles were non-inferior to Fungizone® but not Ambisome®, resulting in significant (~73%) reduction in spleen parasites in 7 days. Particles containing both DETA/NO and AMB were superior (~93% reduction) to Ambisome®. We conclude that NO delivered to the cytosol of macrophages infected with Leishmania possesses intrinsic activity and adds significantly to the efficacy of AMB. © 2016.
Sharma A.,Institute of Nano Science and Technology Institute |
Vaghasiya K.,Institute of Nano Science and Technology Institute |
Verma R.K.,Institute of Nano Science and Technology Institute
Microporous and Mesoporous Materials | Year: 2016
A series of customized inhalable mono-dispersed poly-L-lactide microspheres (PLA-MS) having hierarchical pore structures with either open or closed porosity were synthesized by double emulsion solvent evaporation method using various molar concentrations of porogens. We have presented a simple method for large scale, reproducible synthesis of hierarchically porous PLA-MS, controlling 3D morphologies with well-ordered porosity ranging from ∼2.5 to 850 nm. The prepared PLA-MS were characterized in terms of size, morphology, porosity, cellular uptake using particle size analysis, scanning electron microscopy, Brunauer-Emmett-Teller (BET) and confocal microscopy respectively. We explored, how tailoring the pore size and surface properties of micro-matrix would improve the aerodynamic properties, cellular uptake and release of the bio-therapeutic molecules of variable size. Porous PLA-MS with geometric size 5–10 μm and lower Mass Median Aerodynamic diameter (MMAD) (≤3 μm) shown to aerosolize well, evade macrophages phagocytosis and deposit in deep lungs. These results demonstrated that the type of porogens rather the concentration was more important in generating MS of variable porosity. The in-vitro release profiles of four model-biotherapeutics of significantly different molecular size, from MS of different porosities were investigated up to ∼6 days, their release patterns were found to be significantly different on a chronological basis. It is noteworthy observation that in-vitro cellular phagocytosis of MS is also governed by variable porosity of MS. Our findings shed light on the possible influence of size and porosity of MS on the lung deposition, cellular uptake and sustained delivery of a size-range of biotherapeutics. This approach of tuning porous structures of PLA-MS could be suitable to develop promising inhalable delivery systems. © 2016 Elsevier Inc.