Atomic‐Resolution Three‐Dimensional Structure of Amyloid β Fibrils Bearing the Osaka Mutation

Despite its central importance for understanding the molecular basis of Alzheimer's disease (AD), high‐resolution structural information on amyloid β‐peptide (Aβ) fibrils, which are intimately linked with AD, is scarce. We report an atomic‐resolution fibril structure of the Aβ1‐40 peptide with the Osaka mutation (E22Δ), associated with early‐onset AD. The structure, which differs substantially from all previously proposed models, is based on a large number of unambiguous intra‐ and intermolecular solid‐state NMR distance restraints.     

Carbon‐Dot‐Sensitized,Nitrogen‐Doped TiO2 in Mesoporous Silica for Water Decontamination through Nonhydrophobic Enrichment–Degradation Mode

Mesoporous silica synthesized from the cocondensation of tetraethoxysilane and silylated carbon dots containing an amide group has been adopted as the carrier for the in situ growth of TiO₂ through an impregnation–hydrothermal crystallization process. Benefitting from initial complexation between the titania precursor and carbon dot, highly dispersed anatase TiO₂ nanoparticles can be formed inside the mesoporous channel. The hybrid material possesses an ordered hexagonal mesostructure with p6mm symmetry, a high specific surface area (446.27 m² g^?1), large pore volume (0.57 cm³ g^?1), uniform pore size (5.11 nm), and a wide absorption band between λ=300 and 550 nm. TiO₂ nanocrystals are anchored to the carbon dot through Ti?O?N and Ti?O?C bonds, as revealed by X‐ray photoelectron spectroscopy. Moreover, the nitrogen doping of TiO₂ is also verified by the formation of the Ti?N bond. This composite shows excellent adsorption capabilities for 2,4‐dichlorophenol and acid orange 7, with an electron‐deficient aromatic ring, through electron donor–acceptor interactions between the carbon dot and organic compounds instead of the hydrophobic effect, as analyzed by the contact angle analysis. The composite can be photocatalytically recycled through visible‐light irradiation after adsorption. The narrowed band gap, as a result of nitrogen doping, and the photosensitization effect of carbon dots are revealed to be coresponsible for the visible‐light activity of TiO₂. The adsorption capacity does not suffer any clear losses after being recycled three times.     

Unusual Reactivity of Sodium Tetramesityltetraphosphanediide towards Cyclohexyl Isocyanide

The reaction of [Na₂(thf)₄(P₄Mes₄)] (Mes=2,4,6‐Me₃C₆H₂) with cyclohexyl isocyanide (2:5) resulted in the formation of the heterocyclic N‐(tetramesityltetraphosphacyclopentylidene)cyclohexylamine [cyclo‐{P₄Mes₄C(NCy)}] ( 2 ) (30–35 %), the unusual 1,3,5‐triphospha‐1,4‐pentadiene ( 3 ) (40–45 %), and small amounts of the dimeric iminomethylidenephosphane cyclo‐{PMesC(NCy)}₂ ( 4 ). With catalytic amounts of AgBF₄, 2 was the major product. The reaction of 2 with [CuBr(SMe₂)] (1:1) produced bromido‐bridged dimeric Cu^I complex 5 . Molecular structures of compounds 3 , 4 , and 5 were obtained.     

Assessing the Impact of a Research‐Based STEM Program on STEM Majors' Attitudes and Beliefs

The Science, Engineering, and Technology Gateway of Ohio (SETGO) program has a three‐pronged approach to meeting the needs at different levels of students in the science, technology, engineering, and mathematics (STEM) pipeline. The SETGO program was an extensive collaboration between a two‐year community college and a nearby four‐year institution. Two of these approaches, the STEM Summer Research Program and Owens Ready Bridge, have been found to be effective in significantly increasing participants' beliefs and attitudes for both males and females. Participants cite integrative learning activities, mentoring, and small group interactions as some reasons for their growth. This study utilized a mixed‐method approach to better understand the reasons for participant and program success. After five years of evaluation of the SETGO program, findings suggest that students feel more confident not only in their preparation for the rigors of a STEM degree, but also in their decisions to complete the degree.     

Science as a Learner and as a Teacher: Measuring Science Self‐Efficacy of Elementary Preservice Teachers

Academic science achievement of U.S. students has raised concerns regarding our ability as a nation to compete in a global economy. Additionally, research has shown that many elementary teachers have weak science content backgrounds and had poor/negative experiences as students of science, resulting in a lack of confidence regarding teaching science. However, efforts to increase science self‐efficacy (SE) in preservice teachers can help to combat these issues. This study looked at a sample of preservice elementary teachers engaged in a semester‐long science content course, using Bandura's concept of SE as a conceptual framework. Our quantitative data showed significant increases in science SE on both subscales (personal efficacy and outcome expectancy). Our qualitative data showed that students communicated an increased sense of confidence with regard to the discipline of science. In addition, students reported learning science pedagogy through the instructor's modeling. Combining our findings resulted in several meta‐inferences, one of which showed students growing as both confident learners of science and teachers of science simultaneously. We created a construct new to the literature to describe this phenomenon: “teacher‐learner,” for students are both learning science and learning to teach science simultaneously through the content course experience, resulting in increased science SE.     

Preparation of 2-iodotryptamine and 2-iodo-5-methoxytryptamine

The regiospecific iodination of indole and 5-methoxyindole, and the elaboration of these 2-iodoindoles to the corresponding tryptamines, are described.