Titanium dioxide (TiO2) nanoparticles are used on a massive scale in commercial and industrial products. Of specific concern is how the inhalation of these nanoparticles in a manufacturing setting may affect human health. We examine the cellular response to TiO2 nanoparticles using a combination of cell-free spectroscopic assays, fluorescence microscopy, Western blotting, and TiO2 nanoparticle surface modifications. These experiments show that TiO2 nanoparticles generate superoxide, both in solution and in cells, and this intracellular superoxide decreases expression of histone deacetylase 9 (HDAC9), an epigenetic modifier. We use protein coronas formed from superoxide dismutase (SOD) and catalase, enzymes that scavenge reactive oxygen species (ROS), to probe the relationship between TiO2 nanoparticles, ROS, and the subsequent cellular response. These protein coronas provide nanoparticle-localized scavengers that demonstrate that the nanoparticles are the source of the intracellular superoxide. Importantly, the use of a SOD corona or surface passivated TiO2 nanoparticles prevents the decrease of HDAC9. These experiments elucidate the underlying mechanism of TiO2 nanoparticle-mediated cellular responses including oxidative stress and changes in gene expression. They also provide the first demonstration of a protein corona as a tool for probing cellular responses to nanoparticles. Overall, this research shows that low, nontoxic concentrations of TiO2 nanoparticles alter an enzyme responsible for epigenetic modifications, which points to concerns regarding long-term exposures in manufacturing settings.The development of highly active, stable, and inexpensive molecular water oxidation catalysts (WOCs) is important for eventually realizing artificial photosynthesis. The dinuclear earth-abundant molecular WOCs are of great interest as the latent synergy of two adjacent metals of the molecule could enhance the activity of the catalyst for water oxidation, just as the synergistic catalysis effect of metal ions in many metalloenzymes. Herein we report the dinuclear copper complex [L1Cu2(μ-OH)](BF4)3 (1, L1 = N,N'-dimethyl-N,N'-bis2-[bis(2-pyridinylmethyl)amino]ethylethane-1,2-diamine) with a flexible linker and its mononuclear counterpart [L2Cu(OH2)](BF4)2(2, L2 = N,N-dimethyl-N',N'-bis(2-pyridylmethyl)ethane-1,2-diamine) as WOCs. X-ray diffraction analysis showed that in the crystal structure of 1 there is an extraneous water molecule located very close to the bridged O atom, resembling the proposed structure of the transition state for the O-O bond formation. Comparative studies on the performances of 1 and 2 for electrochemical water oxidation at pH 12 manifested that 1 displayed a much higher activity and better stability than that of 2. The kcat1 of 144 s-1 for 1 is on a par with those of the state-of-the-art earth-abundant molecular WOCs reported to date under similar test conditions. Experimental studies and DFT calculations suggest that the water oxidation catalyzed by 1 proceeds via a unimolecular two-site mechanism with a much lower energy barrier for the O-O bond formation step compared to that for 2.We report the rational design and synthesis of a water-stable metal-organic framework (MOF), Fe-HAF-1, constructed from supramolecular, Fe3+-hydroxamate-based polyhedra with mononuclear metal nodes. Owing to its chelate-based construction, Fe-HAF-1 displays exceptional chemical stability in organic and aqueous solvents over a wide pH range (pH 1-14), including in the presence of 5 M NaOH. Despite the charge neutrality of the Fe3+-tris(hydroxamate) centers, Fe-HAF-1 crystals are negatively charged above pH 4. This unexpected property is attributed to the formation of defects during crystallization that results in uncoordinated hydroxamate ligands or hydroxide-coordinated Fe centers. The anionic nature of Fe-HAF-1 crystals enables selective adsorption of positively charged ions in aqueous solution, resulting in efficient separation of organic dyes and other charged species in a size-selective fashion. Fe-HAF-1 presents a new addition to a small group of chelate-based MOFs and provides a rare framework whose 3D connectivity is exclusively formed by metal-hydroxamate coordination.The separation of alkanes with different degrees of branching, particularly mono- and dibranched isomers, represents a challenging yet important industrial process for the production of premium gasoline blending components with high octane number. We report here the separation of linear/monobranched and dibranched alkanes through complete molecular sieving by a robust aluminum-based MOF material, Al-bttotb (H3bttotb = 4,4',4″-(benzene-1,3,5-triyltris(oxy))tribenzoicacid). Single- and multicomponent adsorption experiments reveal that the material adsorbs linear and monobranched alkanes, but fully excludes their dibranched isomers.  https://www.selleckchem.com/products/cbr-470-1.html  Adsorption sites of alkanes within the MOF channels have been identified by single-crystal X-ray diffraction studies, and the adsorption mechanism was explored through computational calculations and modeling. The highly selective adsorption of the MOF should be attributed to its optimal pore dimensions.We report for the first time a novel series of tellurides bearing sulfonamide as selective and potent inhibitors of the β-class carbonic anhydrase (CA; EC 4.2.1.1) enzyme expressed in Leishmania donovani protozoa. Such derivatives showed high activity against axenic amastigotes, and among them, compound 5g (4-(((3,4,5-trimethoxyphenyl)tellanyl)methyl)benzenesulfonamide) showed an IC50 of 0.02 μM being highly selective for the parasites over THP-1 cells with a selectivity index of 300. The in vitro and in vivo toxicity experiments showed compound 5g to possess a safe profile and thus paving the way for tellurium-containing compounds as novel drug entities.Rhombohedral crystal particles of zeolitic clathrasil deca-dodecasil 3R (DDR), hydrothermally synthesized from a mixture consisting of fumed silica, water, and 1-adamantanamine, were characterized by single-crystal and powder X-ray diffractometry as a function of temperature and pole figure analysis. The crystallite was bounded by six equivalent 101̅1 faces and exhibited twin-free appearance, whereas the structure was resolved with the binary twin by merohedry, defined by the twin point group 3̅2'/m'1, consisting of two twin domains with nearly equal volume fractions. This twinning modifies the positions of O atoms in the Si-O-Si framework while preserving the positions of Si atoms that define the topology of polyhedral cages. This type of twinning therefore does not disrupt the microporous channels via the 8-membered rings of the 19-hedral cages and little disturbs the adsorption and permeation of gas molecules in DDR. The cell volume of DDR increased monotonically with an increase in temperature up to ∼673 K accompanied by an elongation perpendicular to the [0001] axis and a shrinkage along the [0001] axis.