Amyloid β‑Protein Assembly: Differential Effects of the Protective A2T Mutation and Recessive A2V Familial Alzheimer’s Disease Mutation

Oligomeric states of the amyloid β-protein (Aβ) appear to be causally related to Alzheimer’s disease (AD). Recently, two familial mutations in the amyloid precursor protein gene have been described, both resulting in amino acid substitutions at Ala2 (A2) within Aβ. An A2V mutation causes autosomal recessive early onset AD. Interestingly, heterozygotes enjoy some protection against development of the disease. An A2T substitution protects against AD and age-related cognitive decline in non-AD patients. Here, we use ion mobility-mass spectrometry (IM-MS) to examine the effects of these mutations on Aβ assembly. These studies reveal different assembly pathways for early oligomer formation for each peptide. A2T Aβ42 formed dimers, tetramers, and hexamers, but dodecamer formation was inhibited. In contrast, no significant effects on Aβ40 assembly were observed. A2V Aβ42 also formed dimers, tetramers, and hexamers, but it did not form dodecamers. However, A2V Aβ42 formed trimers, unlike A2T or wild-type (wt) Aβ42. In addition, the A2V substitution caused Aβ40 to oligomerize similar to that of wt Aβ42, as evidenced by the formation of dimers, tetramers, hexamers, and dodecamers. In contrast, wt Aβ40 formed only dimers and tetramers. These results provide a basis for understanding how these two mutations lead to, or protect against, AD. They also suggest that the Aβ N-terminus, in addition to the oft discussed central hydrophobic cluster and C-terminus, can play a key role in controlling disease susceptibility

Amyloid β‑Protein Assembly: The Effect of Molecular Tweezers CLR01 and CLR03

The early oligomerization of amyloid β-protein (Aβ) has been shown to be an important event in the pathology of Alzheimer’s disease (AD). Designing small molecule inhibitors targeting Aβ oligomerization is one attractive and promising strategy for AD treatment. Here we used ion mobility spectrometry coupled to mass spectrometry (IMS-MS) to study the different effects of the molecular tweezers CLR01 and CLR03 on Aβ self-assembly. CLR01 was found to bind to Aβ directly and disrupt its early oligomerization. Moreover, CLR01 remodeled the early oligomerization of Aβ42 by compacting the structures of dimers and tetramers and as a consequence eliminated higher-order oligomers. Unexpectedly, the negative-control derivative, CLR03, which lacks the hydrophobic arms of the tweezer structure, was found to facilitate early Aβ oligomerization. Our study provides an example of IMS as a powerful tool to study and better understand the interaction between small molecule modulators and Aβ oligomerization, which is not attainable by other methods, and provides important insights into therapeutic development of molecular tweezers for AD treatment

Correction to “Anisotropic Growth of TiO₂ onto Gold Nanorods for Plasmon-Enhanced Hydrogen Production from Water Reduction”

Correction to “Anisotropic Growth of TiO₂ onto Gold Nanorods for Plasmon-Enhanced Hydrogen Production from Water Reduction

Microwave Synthesis of Microstructured and Nanostructured Metal Chalcogenides from Elemental Precursors in Phosphonium Ionic Liquids

We describe a general approach for the synthesis of micro-/nanostructured metal chalcogenides from elemental precursors. The excellent solubility of sulfur, selenium, and tellurium in phosphonium ionic liquids promotes fast reactions between chalcogens and various metal powders upon microwave heating, giving crystalline products. This approach is green, universal, and scalable

Crystalline Medium-Bandgap Light-Harvesting Donor Material Based on <i>β-</i>Naphthalene Asymmetric-Modified Benzodithiophene Moiety toward Efficient Polymer Solar Cells

In this paper, we reported a crystalline p-type medium-bandgap conjugated D–A polymer <i>asy</i>-PBDBTN based on a symmetry-breaking-modified BDT moiety to combine the advantages of both one-dimension (1D) and two-dimension (2D) symmetric BDTs. Polymer <i>asy</i>-PBDBTN is a highly efficient light-harvesting donor material. Single BHJ PSCs exhibit PCE of 8.88% with PC₇₁BM as acceptor. Also, PCE values of 10.50% are achieved with the use of ITIC as an acceptor to couple <i>asy</i>-PBDBTN with <i>V</i>_OC of 0.942 V, <i>J</i>_SC of 16.81 mA cm^–2, and FF of 0.663. It is worth noting that lower energy loss is obtained in fullerene-free-based PSCs, which is essential to overcome the trade-off between <i>V</i>_OC and <i>J</i>_SC and boost these two parameters simultaneously for high photovoltaic performance. The combination process of additive and thermal annealing is critical to enhance and retain the π–π stacking behavior of donor and fullerene-free acceptor; as a result, the trap-assisted recombination was greatly suppressed. This work demonstrates a great prospect for the construction of the symmetry-breaking BDT-based D–A conjugated polymers toward high-performance PSCs, especially with fullerene-free acceptor material

Nanostructured Mn-Doped V₂O₅ Cathode Material Fabricated from Layered Vanadium Jarosite

We propose a nanostructured Mn-doped V₂O₅ lithium-ion battery cathode material that facilitates cathodic charge transport. The synthesis strategy uses a layered compound, vanadium­(III) jarosite, as the precursor, in which the Mn²⁺ ions are doped uniformly between the vanadium oxide crystal layers. Through a two-step transformation, the vanadium jarosite was converted into Mn²⁺-doped V₂O₅. The resulting aliovalent doping of the larger Mn cations in the modified V₂O₅ structure increases the cell volume, which facilitates diffusion of Li⁺ ions, and introduces oxygen vacancies that improve the electronic conductivity. Comparison of the electrochemical performance in Li-ion batteries of undoped and the Mn²⁺-doped V₂O₅ hierarchical structure made from layered vanadium jarosite confirms that the Mn-doping improves ion transport to give a high cathodic columbic capacity (253 mAhg^–1 at 1C, 86% of the theoretical value, 294 mAhg^–1) and excellent cycling stability

Multimodal Study of the Speciations and Activities of Supported Pd Catalysts During the Hydrogenation of Ethylene

In this work we describe a multimodal exploration of the atomic structure and chemical state of silica-supported palladium nanocluster catalysts during the hydrogenation of ethylene in <i>operando</i> conditions that variously transform the metallic phases between hydride and carbide speciations. The work exploits a microreactor that allows combined multiprobe investigations by high-resolution transmission electron microscopy (HR-TEM), X-ray absorption fine structure (XAFS), and microbeam IR (μ-IR) analyses on the catalyst under <i>operando</i> conditions. The work specifically explores the reaction processes that mediate the interconversion of hydride and carbide phases of the Pd clusters in consequence to changes made in the composition of the gas-phase reactant feeds, their stability against coarsening, the reversibility of structural/compositional transformations, and the role that oligomeric/waxy byproducts (here forming under hydrogen-limited reactant compositions) might play in modifying activity. The results provide new insights into structural features of the chemistry/mechanisms of Pd catalysis during the selective hydrogenation of acetylene in ethylenea process simplified here in the use of binary ethylene/hydrogen mixtures. These explorations, performed in <i>operando</i> conditions, provide new understandings of structure–activity relationships for Pd catalysis in regimes that actively transmute important attributes of electronic and atomic structures

Inkjet Printing Assisted Synthesis of Multicomponent Mesoporous Metal Oxides for Ultrafast Catalyst Exploration

We describe an inkjet printing assisted cooperative-assembly method for high-throughput generation of catalyst libraries (multicomponent mesoporous metal oxides) at a rate of 1 000 000-formulations/hour with up to eight-component compositions. The compositions and mesostructures of the libraries can be well-controlled and continuously varied. Fast identification of an inexpensive and efficient quaternary catalyst for photocatalytic hydrogen evolution is achieved via a multidimensional group testing strategy to reduce the number of performance validation experiments (25 000-fold reduction over an exhaustive one-by-one search)

Inkjet Printing Assisted Synthesis of Multicomponent Mesoporous Metal Oxides for Ultrafast Catalyst Exploration

We describe an inkjet printing assisted cooperative-assembly method for high-throughput generation of catalyst libraries (multicomponent mesoporous metal oxides) at a rate of 1 000 000-formulations/hour with up to eight-component compositions. The compositions and mesostructures of the libraries can be well-controlled and continuously varied. Fast identification of an inexpensive and efficient quaternary catalyst for photocatalytic hydrogen evolution is achieved via a multidimensional group testing strategy to reduce the number of performance validation experiments (25 000-fold reduction over an exhaustive one-by-one search)

Identifying Dynamic Structural Changes of Active Sites in Pt–Ni Bimetallic Catalysts Using Multimodal Approaches

Alloy nanoparticle catalysts are known to afford unique activities that can differ markedly from their parent metals, but there remains a generally limited understanding of the nature of their atomic (and likely dynamic) structures as exist in heterogeneously supported forms under reaction conditions. Notably unclear is the nature of their active sites and the details of the varying oxidation states and atomic arrangements of the catalytic components during chemical reactions. In this work, we describe multimodal methods that provide a quantitative characterization of the complex heterogeneity present in the chemical and electronic speciations of Pt–Ni bimetallic catalysts supported on mesoporous silica during the reverse water gas shift reaction. The analytical protocols involved a correlated use of in situ X-ray Absorption Spectroscopy (XAS) and Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS), complimented by ex-situ aberration corrected Scanning Transmission Electron Microscopy (STEM). The data reveal that complex reactions occur between the metals and support in this system under operando conditions. These reactions, and the specific impacts of strong metal–silica bonding interactions, prevent the formation of alloy phases containing Ni–Ni bonds. This feature of structure provides high activity and selectivity for the reduction of CO₂ to carbon monoxide without significant competitive levels of methanation. We show how these chemistries evolve to the active state of the catalyst: bimetallic nanoparticles possessing an intermetallic structure (the active phase) that are conjoined with Ni-rich, metal-silicate species