The Application of the Engineering Design Process to Curriculum Revision: A Collaborative Approach to STEM Curriculum Refinement in an Urban District

This study describes how student unit assessment data helped support ongoing curriculum revisions in the Baltimore City School District. This project is situated in the STEM Achievement in Baltimore Elementary Schools (SABES) project, which is a National Science Foundation funded multi‐year Math Science Partnership between the Johns Hopkins University and the Baltimore City School District. The project focuses on improving STEM education in grades three through five. The study modeled the process of curriculum revision after the engineering design process. One of the units developed by the partnership was analyzed using this revision process. Areas of unit revision and modification were identified utilizing the analysis of pre‐ and post‐assessment data from the implementation of the unit. Constraints represented by standards, unit objectives, and student‐reading levels further informed the revision process. The process resulted in modifications to aspects of the unit and assessment. Findings from this work will help inform collaborative curriculum initiatives between institutions of higher education public school districts.     

Preparing to read the ubiquitin code: characterization of ubiquitin trimers by top‐down mass spectrometry

The profound effects of ubiquitination on the movement and processing of cellular proteins depend exquisitely on the structures of monoubiquitin and polyubiquitin modifications. Unconjugated polyubiquitins also have a variety of intracellular functions. Structures and functions are not well correlated yet, because the structures of polyubiquitins and polyubiquitin modifications of proteins are difficult to decipher. We are moving towards a robust strategy to provide that structural information. In this report electron transfer dissociation mass spectra of six synthetic ubiquitin trimers (multiply branched proteins with molecular masses exceeding 25 600 Da) are examined using an Orbitrap Fusion Lumos instrument to determine how top‐down mass spectrometry can characterize the chain topology and linkage sites in a single, facile workflow. The efficacy of this method relies on the formation, detection, and interpretation of extensive fragmentation. Copyright © 2016 John Wiley & Sons, Ltd.     

Insertion of Isocyanides into N−Si Bonds: Multicomponent Reactions with Azines Leading to Potent Antiparasitic Compounds

Trimethylsilyl chloride is an efficient activating agent for azines in isocyanide‐based reactions, which then proceed through a key insertion of the isocyanide into a N?Si bond. The reaction is initiated by N activation of the azine, followed by nucleophilic attack of an isocyanide in a Reissert‐type process. Finally, a second equivalent of the same or a different isocyanide inserts into the N?Si bond leading to the final adduct. The use of distinct nucleophiles leads to a variety of α‐substituted dihydroazines after a selective cascade process. Based on computational studies, a mechanistic hypothesis for the course of these reactions was proposed. The resulting products exhibit significant activity against Trypanosoma brucei and T. cruzi, featuring favorable drug‐like properties and safety profiles.     

Raman enhancement of azobenzene monolayers on substrates prepared by Langmuir-Blodgett deposition and electron-beam lithography techniques

Nanostructured metallic platforms for Raman enhancement were fabricated using Langmuir-Blodgett and electron beam (e-beam) lithography techniques. The gold platforms were inscribed on thin glass slides with the purpose of using them in a transmission geometry experimental setup under a confocal microscope. The plasmon frequency of the gold nanostructures was determined in the visible-near-infrared range for various pattern sizes prepared by Langmuir-Blodgett transfer and e-beam lithography. The surface Raman enhancement factors were determined for a monolayer of azobenzene molecules adsorbed on gold through thiol bonding and compared for both LB transfer and e-beam samples for nanostructures of comparable geometries.     

Contact angles of submillimeter particles: connecting wettability to nanoscale surface topography

A method is presented for the measurement of contact angles of particles in the size range 100-1000 microm, using an optical microscope. This method is used to characterize the wettability of polyethylene particles produced in a gas-phase polymerization process. The as-polymerized particles are shown to be significantly more hydrophobic than melt-processed polyethylene materials. The surface structure of the particles is examined with scanning electron microscopy, and the increased hydrophobicity of the as-polymerized particles is attributed to the nanoscale texture of the particle surfaces.     

Synthesis and biochemical evaluation of 3,7-disubstituted farnesyl diphosphate analogues

Farnesyl diphosphate (FPP) analogues have proven to be both potent inhibitors of protein-farnesyltransferase (FTase) and valuable probes for the investigation of the function of prenylated proteins. Previously, we have demonstrated that certain 3-substituted and 7-substituted FPP analogues can act as inhibitors of FTase, while others are effective alternative substrates. We have now utilized our vinyl triflate-mediated route to synthesize the first seven FPP variants bearing substituents in both the 3- and 7-positions of the isoprene unit. Despite their exceptional steric bulk with respect to FPP itself, six of the seven analogues bind to FTase. Two of the analogues are potent inhibitors of the enzyme, but a more striking finding is that three FPP variants (4a, 4b, and 4f) are efficient alternative substrates for FTase.     

Template-assisted synthesis of shape-controlled Rh2P nanocrystals

When reacted with trioctylphosphine at approximately 360 degrees C, rhodium nanocrystals convert to rhodium phosphide Rh(2)P nanocrystals. Careful control over synthetic variables, such as temperature, stabilizing ligands, and cosolvents, can result in Rh(2)P nanocrystals with shapes that reflect the Rh nanocrystal templates. Accordingly, Rh nanocrystals with multipod, cube- and triangle-derived shapes convert to Rh(2)P nanocrystals that maintain the shape of their Rh precursors. Both dense and hollow Rh(2)P nanocrystals can be generated using a single unified chemical conversion strategy. These empirical guidelines for generating a morphologically diverse library of Rh(2)P nanocrystals provide important insights into shape conservation using nanocrystal templates and will likely be portable to other multielement systems for which rigorous shape-controlled synthesis remains challenging.     

Zinc carboxylate cluster formation in conjugated metallomacrocycles: evidence for templation

A new [3 + 3] Schiff base macrocycle incorporating three N2O2 salphen-type binding sites and peripheral neopentyloxy substituents has been prepared. The incorporation of Zn2+ ions into this and related conjugated Schiff base macrocycles has been studied by NMR spectroscopy, mass spectrometry, and X-ray diffraction. When reacted with 7 equiv of zinc acetate, the macrocycles template the formation of heptanuclear complexes. Two tetranuclear Zn2+ complexes that are plausible intermediates in the assembly of the heptanuclear complexes have been isolated and structurally characterized. These reactive intermediates are promising substrates for the synthesis of polynuclear, mixed-metal clusters. We also demonstrate that this chemistry may be generalized to other bridging carboxylate ligands, such as methacrylate.     

Dynamics at conical intersections: the influence of O-H stretching vibrations on the photodissociation of phenol

Comparing the recoil energy distributions of the fragments from one-photon dissociation of phenol-d(5) with those from vibrationally mediated photodissociation shows that initial vibrational excitation strongly influences the disposal of energy into relative translation. The measurements use velocity map ion imaging to detect the H-atom fragments and determine the distribution of recoil energies. Dissociation of phenol-d(5) molecules with an initially excited O-H stretching vibration produces significantly more fragments with low recoil energies than does one-photon dissociation at the same total energy. The difference appears to come from the increased probability of adiabatic dissociation in which a vibrationally excited molecule passes around the conical intersection between the dissociative state and the ground state to produce electronically excited phenoxyl-d(5) radicals. The additional energy deposited in electronic excitation of the radical reduces the energy available for relative translation.