Physical Sciences and Mathematics Commons^™

A Simple Sn2 Reaction For The Undergraduate Organic Laboratory, John Esteb

John Esteb

A simple procedure for the synthesis of n-butyl naphthyl ether is presented. This procedure represents an easy method for the production of an aryl ether by an SN2 reaction, uses ethanol as an environmentally friendly solvent, and does not require the use of a lachrymator. Product isolation is done by pouring the reaction mixture over ice and collecting the solid by suction filtration. Students typically recover from 7–95% of the ether.

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A Flexible Solvolysis Experiment For The Undergraduate Organic Laboratory, John Esteb, John Magers, Luanne Mcnulty, Paul Morgan, Kathryn Tindell, Anne Wilson

John Esteb

A simple SN1 reaction is presented that uses bromotriphenylmethane and a range of oxygen-based nucleophiles including water and various alcohols. This procedure represents a process that affords easy isolation of solid products. Typical student yields ranged from 17–128% with the average yield of 50%. Students obtained products with a melting point range of 140 to 164 °C. This procedure offers multiple ways to adapt this experiment from a straight solvolysis reaction to a discovery-based experiment that explores the effect of nucleophile (for a more advanced group) or the method of product isolation. Note: Link is to the article in a …

Variation In Levels Of Reactive Oxygen Species Is Explained By Maternal Identity, Sex And Body-Size-Corrected Clutch Size In A Lizard, Mark Wilson, Mats Olsson, Tobias Uller, Caroline Isaksson, Beth Mott

Mark R Wilson

No abstract provided.

A Perturbation Drbem Model For Weakly Nonlinear Wave Run-Ups Around Islands, Tim Marchant

Tim Marchant

In this paper, the dual reciprocity boundary element method (DRBEM) based on the perturbation method is presented for calculating run-ups of weakly nonlinear long waves scattered by islands. Under the assumption that the incident waves are harmonic, the time-dependent nonlinear Boussinesq equations are transformed into three time-independent linear equations by using the perturbation method, where, besides nonlinearity ε, the dispersion μ2 is also included in the perturbed expansion. The first-order solution η0 is found by using the linear long-wave equations. Then η0 is used in two second-order governing equations related to the dispersion and nonlinearity, respectively. Since no any omission …

Easy Steps To Success: A Graphing Calculator Guide, Lisa Yocco, Ronald Harshbarger

Lisa S. Yocco

No abstract provided.

The Chaperone Action Of Clusterin And Its Putative Role In Quality Control Of Extracellular Protein Folding, Amy Wyatt, Justin Yerbury, Stephen Poon, Rebecca Dabbs, Mark Wilson

Mark R Wilson

The function(s) of clusterin may depend upon its topological location. A variety of intracellular "isoforms" of clusterin have been reported but further work is required to better define their identity. The secreted form of clusterin has a potent ability to inhibit both amorphous and amyloid protein aggregation. In the case of amorphous protein aggregation, clusterin forms stable, soluble high-molecular-weight complexes with misfolded client proteins. Clusterin expression is increased during many types of physiological and pathological stresses and is thought to function as an extracellular chaperone (EC). The pathology of a variety of serious human diseases is thought to arise as …

Agenda For A Sustainable America, John Dernbach

John C. Dernbach

No abstract provided.

An Agenda For Sustainable Communities, John Dernbach

John C. Dernbach

This article summarizes progress toward sustainable communities in the United States since the United Nations Conference on Environment and Development (or Earth Summit) in 1992. It shows the significant initiative that many communities have undertaken and identifies existing state and federal laws as impediments to achieving sustainability. This article also makes recommendations for further progress based on what we have already learned about how to achieve sustainable communities. They include not only more and strengthened sustainable community efforts, and broad state and federal legal support, but also deep engagement of all affected citizens. This article is based primarily on three …

The Architecture Of Platforms: A Unified View, Carliss Y. Baldwin, C. Jason Woodard

C. Jason Woodard

No abstract provided.

Highly Fluorous Complexes Of Ruthenium And Osmium And Their Solubility In Supercritical Carbon Dioxide, Brad Berven, George Koutsantonis, Brian Skelton, Robert Trengove, Allan White

Brad Berven

A series of ruthenium and osmium complexes containing highly fluorous diphosphine ligands FPPF = (F13C6C6H4-p)2P(CH2)2P(p-C6H4C6F13)2 (dfppe) and (F13C6C6H4-p)2P(CH2)3P(p-C6H4C6F13)2 (dfppp) has been prepared. The fluorous diphosphine ligands incorporate four C6F13 “fluoro-ponytails”, and these have been effective in solubilizing the complexes in supercritical carbon dioxide (scCO2). Precise solubility measurements in scCO2 were performed for some of the complexes. The new complexes [MX2(FPPF)2] and [MX(FPPF)(η-C5H5)], M = Ru, Os, X = Cl, Br, have been characterized by a number of spectroscopic techniques and their electrochemical properties measured, three of the ruthenium complexes also being characterized by single-crystal X-ray studies. The noncovalent interactions observed …

Properties Of Multilevel Block $\Alpha$-Circulants, William F. Trench

William F. Trench

No abstract provided.

On Nonautonomous Linear Systems Of Differential And Difference Equations With $R$-Symmetric Coefficient Matrices, William F. Trench

William F. Trench

No abstract provided.

Sub-Micron Parallel Laser Direct-Write, Christina Othon, Arnoldo Laracuente, H Ladoucuer, Bradley Ringeisen

Christina M Othon

We have developed a modified laser induced forward transfer (LIFT) technique which allows for the parallel deposition of hundreds of sub-micron features. The approach utilizes a self-assembled monolayer of monodisperse polystyrene microspheres as the focusing element. A monolayer of close-packed microspheres is formed on top of an ultra-thin quartz support (25 m thick), and a metallic thin film is then deposited on the underside of the quartz. This approach is different from previous parallel microsphere-assisted LIFT experiments that required the deposition of metal directly onto the surface of the periodic microsphere structure. For this study, an 800 nm, 130 fs …

An Aztec 1.1 Mm Survey Of The Goods-N Field – I. Maps, Catalogue And Source Statistics, Thushara Perera, E. Chapin, J. Austermann, K. Scott, G. Wilson, M. Halern, A. Pope, D. Scott, M. Yun, J. Lowenthal, G. Morrison, I. Aretxaga, J. Bock, K. Coppin, M. Crowe, L. Frey, D. Hughes, Y. Kang, S. Kim, P. Mauskopf

Thushara A. Perera

No abstract provided.

Towards Self-Organizing, Smart Business Networks: Let’S Create ‘Life’ From Inert Information, David Bray, Benn Konsynski

David A. Bray

We review three different theories that can inform how researchers can determine the performance of smart business networks, to include: (1) the Theory of Evolution, (2) the Knowledge-Based Theory of the Firm, and (3) research insights into computers and cognition. We suggest that each of these theories demonstrate that to be generally perceived as smart, an organism needs to be self-organizing, communicative, and tool-making. Consequentially, to determine the performance of a smart business network, we suggest that researchers need to determine the degree to which it is self-organizing, communicative, and tool-making. We then relate these findings to the Internet and …

Adhesion And Interfacial Fracture Toughness Between Hard And Soft Materials, Nima Rahbar, Kurt Wolf, Argjenta Orana, Roy Fennimore, Zong Zong, Juan Meng, George Papandreou, Cynthia Maryanoff, Wole Soboyejo

Nima Rahbar

This paper presents the results of a combined experimental and theoretical study of adhesion between hard and soft layers that are relevant to medical devices such as drug-eluting stents and semiconductor applications. Brazil disk specimens were used to measure the interfacial fracture energies between model parylene C and 316L stainless steel over a wide range of mode mixities. The trends in the overall fracture energies are predicted using a combination of adhesion theories and fracture mechanics concepts. The measured interfacial fracture energies are shown to be in good agreement with the predictions.

Potential Driven Deposition Of Poly(Diallyldimethylammonium Chloride) Onto The Surface Of 3-Mercaptopropionic Acid Monolayers Assembled On Gold, Wesley Sanders, Mark Anderson

Mark R. Anderson

Electrochemical impedance spectroscopy (EIS) and quartz crystal microbalance (QCM) measurements are used to examine the ability of applied potential to drive the ionic self-assembly of poly(diallyldimethylammonium) chloride (PDDA) onto a substrate modified with a monolayer of 3-mercaptopropionic acid (3-MPA). The potential of zero charge (PZC) of the gold electrode modified with a monolayer of 3-MPA was found by differential capacitance measurements to be −0.12 (±0.01) V versus Ag−AgCl. Changing the substrate potential to values positive (−0.01 V vs Ag−AgCl) of the PZC induces interfacial conditions that are favorable for the electrostatic deposition of cationic polymers onto the surface of 3-MPA …

The Role Of Science And Engineering In Water Regulation Over The Past 100 Years, James R. May, Patrick Clary

James R. May

This article explores how scientific and engineering principles are inexorably linked to the regulation of water. Scientists and engineers first discovered the link between disease and water sources in the mid-19th century. Over the years, scientists and engineers have led the way to identifying water quality problems and their causes. These discoveries have directly contributed to the scope of water regulation in the United States and elsewhere. In addition, changes in water quality regulation have dictated the need for increasingly sophisticated water treatment technologies and engineers have been at the forefront of the development of these water control technologies. This …

Sequence Specific And High Affinity Recognition Of 5′-Acgcgt-3′ By Rationally Designed Pyrrole-Imidazole H-Pin Polyamides: Thermodynamic And Structural Studies., Hilary Mackay, Toni Brown, Peter Uthe, Laura Westrate, Alan Sielaff, Justin Jones, James Lajiness, Jerome Kluza, Caroline O'Hare, Binh Nguyen, Zach Davis, Chrystal Bruce, W. Wilson, John Hartley, Moses Lee

Chrystal D. Bruce

Imidazole (Im) and Pyrrole (Py)-containing polyamides that can form stacked dimers can be programmed to target specific sequences in the minor groove of DNA and control gene expression. Even though various designs of polyamides have been thoroughly investigated for DNA sequence recognition, the use of H-pin polyamides (covalently cross-linked polyamides) has not received as much attention. Therefore, experiments were designed to systematically investigate the DNA recognition properties of two symmetrical H-pin polyamides composed of PyImPyIm (5) or f-ImPyIm (3e, f=formamido) tethered with an ethylene glycol linker. These compounds were created to recognize the cognate 5′-ACGCGT-3′ through an overlapped and staggered …

Spatio-Temporal Efficiency In A Taxi Dispatch System, Darshan Santani, Rajesh Krishna Balan, C. Jason Woodard

C. Jason Woodard

In this paper, we present an empirical analysis of the GPS-enabled taxi dispatch system used by the world’s second largest land transportation company. We first summarize the collective dynamics of the more than 6,000 taxicabs in this fleet. Next, we propose a simple method for evaluating the efficiency of the system over a given period of time and geographic zone. Our method yields valuable insights into system performance—in particular, revealing significant inefficiencies that should command the attention of the fleet operator. For example, despite the state of the art dispatching system employed by the company, we find imbalances in supply …

Intersecting Families And Definability, Andrés Caicedo

Andrés E. Caicedo

No abstract provided.

Significant Figures, Tony Badrick, Peter Hickman

Tony Badrick

For consistency of reporting the same number of significant figures should be used for results and reference intervals. The choice of the reporting interval should be based on analytical imprecision (measurement uncertainty).

A Symbolic Operator Approach To Power Series Transformation-Expansion Formulas, Tian-Xiao He

Tian-Xiao He

In this paper we discuss a kind of symbolic operator method by making use of the defined Sheffer-type polynomial sequences and their generalizations, which can be used to construct many power series transformation and expansion formulas. The convergence of the expansions are also discussed.

The Study Of Optogalvanic Effect Associated With The 1s States Of Neon, Naveed Piracha, K. Nesbett, S. Marotta

Naveed K. Piracha

We report on the temporal evolution of the optogalvanic signals in neon using a commercial hollow cathode lamp in conjunction with a Nd:YAG pumped dye laser system. We have recorded transitions excited from each of the neon 1s states over a range of discharge current to investigate the dominant physical processes responsible for the optogalvanic effect in neon discharges. The decay rates associated with the four 1s levels have been obtained using a mathematical rate equation model. A linear relationship between the decay rates and the discharge current has been found and the effective lifetimes and the electron collisional rate …

Characterization Of Carboxylic Acid-Terminated Self-Assembled Monolayers By Electrochemical Impedance Spectroscopy And Scanning Electrochemical Microscopy, Wesley Sanders, Ricardo Vargas, Mark Anderson

Mark R. Anderson

Electrochemical impedance spectroscopy (EIS) and scanning electrochemical microscopy (SECM) are used to monitor changes in the ionization of monolayers of 11-mercaptoundecanoic acid. When using an anionic redox probe, Fe(CN)6−4, the charge-transfer resistance of the 11-mercaptoundecanoic acid monolayer-modified interface increases in a sigmoidal fashion as the solution is made basic. The opposite effect is observed when using a cationic redox probe. The inflection points of these two titration curves, however, differ when using the different redox probes. This result is taken as being characteristic of the influence that applied potential has on the ionization of the monolayer. The role of substrate …

Locally Adaptive Nonparametric Binary Regression, Sally Wood, Martin Tanner, Wenxin Jiang, Robert Kohn, Remy Cottet

Sally Wood

No abstract provided.

A Self-Organizing Map For Adaptive Processing Of Structured Data, Markus Hagenbuchner, A. Sperduti, Ah Chung Tsoi

Ah Chung Tsoi

Recent developments in the area of neural networks produced models capable of dealing with structured data. Here, we propose the first fully unsupervised model, namely an extension of traditional self-organizing maps (SOMs), for the processing of labeled directed acyclic graphs (DAGs). The extension is obtained by using the unfolding procedure adopted in recurrent and recursive neural networks, with the replicated neurons in the unfolded network comprising of a full SOM. This approach enables the discovery of similarities among objects including vectors consisting of numerical data. The capabilities of the model are analyzed in detail by utilizing a relatively large data …

Simulation And Analysis Of Ultrafast-Laser-Pulse-Induced Plasma Generation In Fused Silica, Jeremy Gulley, Sebastian Winkler, W. M. Dennis

Jeremy R. Gulley

Recent experiments on optical damage by ultrashort laser pulses have demonstrated that the temporal pulse shape can dramatically influence plasma generation in fused silica. We use a modified 3+1D nonlinear Schrödinger equation for the pulse propagation coupled to a rate equation for the plasma density in the dielectric material to simulate pulse propagation and plasma formation in fused silica. We use these simulations to analyze the influence of pulse shape and beam geometry on the formation of the electron plasma and hence modification in the bulk material. In particular, we simulate the effect of pulses reconstructed from experimental data. It …

Modifying The N-Terminus Of Polyamides: Pyimpyim Has Improved Sequence Specificity Over F-Impyim, Toni Brown, Hilary Mackay, Mark Turlington, Arden Sutterfield, Traci Smith, Alan Sielaff, Laura Westrate, Chrystal Bruce, Jerome Kluza, Caroline O'Hare, Binh Nguyen, W. Wilson, John Hartley, Moses Lee

Chrystal D. Bruce

Seven N-terminus modified derivatives of a previously published minor-groove binding polyamide (f-ImPyIm, 1) were synthesized and the biochemical and biophysical chemistry evaluated. These compounds were synthesized with the aim of attaining a higher level of sequence selectivity over f-ImPyIm (1), a previously published strong minor-groove binder. Two compounds possessing a furan or a benzofuran moiety at the N-terminus showed a footprint of 0.5μM at the cognate ACGCGT site (determined by DNase I footprinting); however, the specificity of these compounds was not improved. In contrast, PyImPyIm (4) produced a footprint of 0.5μM but showed a superior specificity using the same technique. …

Simultaneous Determination Of Glucose And L‐Glutamate Using A Capillary Enzyme Reactor With Electrochemical Detection, Stephanie Hooper, Mark Anderson

Mark R. Anderson

An electrophoresis capillary that incorporates two enzymes for the simultaneous determination of glucose and l-glutamate is described. The enzymes deposited along the separation capillary walls react with their respective substrate as they are separated during the electrophoresis to produce hydrogen peroxide that is detected by amperometry as the hydrogen peroxide zone emerges from the end of the capillary. Even though both enzyme reactions produce a common product, hydrogen peroxide, the hydrogen peroxide produced by each enzyme reaction stays in narrow zones that migrate the length of the capillary at different rates. The rate of migration for the individual H2O2 zones …