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Physical Sciences and Mathematics Commons™

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Loyola University Chicago

2006

Articles 1 - 9 of 9

Full-Text Articles in Physical Sciences and Mathematics

Unit Testing Considered Useful, George K. Thiruvathukal, Konstantin Läufer, Benjamin Gonzalez Nov 2006

Unit Testing Considered Useful, George K. Thiruvathukal, Konstantin Läufer, Benjamin Gonzalez

Computer Science: Faculty Publications and Other Works

Testing is an important part of application development. Hardware engineers, in particular, have a long established history of testing for the obvious reason that it's awfully hard to rebuild a microprocessor every time a bug pops up in the design stage--not to mention the enormous headaches such bugs generate on the software side.

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Electronic Editing Of Anglo-Saxon Texts, George K. Thiruvathukal, Allen J. Frantzen Nov 2006

Electronic Editing Of Anglo-Saxon Texts, George K. Thiruvathukal, Allen J. Frantzen

Computer Science: Faculty Publications and Other Works

Poster presentation/demonstration at the first Chicago Colloquium on Digital Humanities about editing of Old English texts and the Anglo-Saxon project.

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Three-Terminal Devices To Examine Single Molecule Conductance Switching, Z K. Keane, Jacob W. Ciszek, J M. Tour, D Natelson Jul 2006

Three-Terminal Devices To Examine Single Molecule Conductance Switching, Z K. Keane, Jacob W. Ciszek, J M. Tour, D Natelson

Chemistry: Faculty Publications and Other Works

We report electronic transport measurements of single-molecule transistor devices incorporating bipyridyl-dinitro oligophenylene-ethynylene dithiol (BPDN-DT), a molecule known to exhibit conductance switching in other measurement configurations. We observe hysteretic conductance switching in 8% of devices with measurable currents, and find that dependence of the switching properties on gate voltage is rare when compared to other single-molecule transistor devices. This suggests that polaron formation is unlikely to be responsible for switching in these devices. We discuss this and alternative switching mechanisms.

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Single-Molecule Transistors: Electron Transfer In The Solid State, Douglas Natelson, Lam H. Yu, Jacob W. Ciszek, Zachary K. Keane, James M. Tour May 2006

Single-Molecule Transistors: Electron Transfer In The Solid State, Douglas Natelson, Lam H. Yu, Jacob W. Ciszek, Zachary K. Keane, James M. Tour

Chemistry: Faculty Publications and Other Works

Single-molecule transistors (SMTs) incorporating individual small molecules are unique tools for examining the fundamental physics and chemistry of electronic transport in molecular systems at the single nanometer scale. We describe the fabrication and characterization of such devices, and the synthesis and surface attachment chemistry of novel transition metal complexes that have been incorporated into such SMTs. We present gate-modulated inelastic electron tunneling vibrational spectroscopy of single molecules, strong Kondo physics (TK ∼ 75 K) as evidence of excellent molecule/electrode electronic coupling, and a demonstration that covalent attachment chemistry can produce SMTs that survive repeated thermal cycling to room …

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Scalable Approaches For Supporting Mpi-Io Atomicity, Peter Aarestad, George K. Thiruvathukal, Avery Ching, Alok Choudhary May 2006

Scalable Approaches For Supporting Mpi-Io Atomicity, Peter Aarestad, George K. Thiruvathukal, Avery Ching, Alok Choudhary

Computer Science: Faculty Publications and Other Works

Scalable atomic and parallel access to noncontiguous regions of a file is essential to exploit high performance I/O as required by large-scale applications. Parallel I/O frameworks such as MPI I/O conceptually allow I/O to be defined on regions of a file using derived datatypes. Access to regions of a file can be automatically computed on a perprocessor basis using the datatype, resulting in a list of (offset, length) pairs. We describe three approaches for implementing lock serving (whole file, region locking, and byterange locking) and compare the various approaches using three noncontiguous I/O benchmarks. We present the details of the …

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Pyrrolizidine Esters And Amides As 5-Ht4 Receptor Agonists And Antagonists, Daniel Becker, Daniel L. Flynn, Alan E. Moormann, Roger Nosal Feb 2006

Pyrrolizidine Esters And Amides As 5-Ht4 Receptor Agonists And Antagonists, Daniel Becker, Daniel L. Flynn, Alan E. Moormann, Roger Nosal

Chemistry: Faculty Publications and Other Works

A series of pyrrolizidine esters, amides, and ureas was prepared and tested for 5-HT(4) and 5-HT(3) receptor binding, 5-HT(4) receptor agonism in the rat tunica muscularis mucosae (TMM) assay, and for 5-HT(3) receptor-mediated functional antagonism in the Bezold-Jarisch reflex assay. Several pyrrolizidine derivatives were identified with high affinity for the 5-HT(4) receptor, including benzamide 12a (SC-53116), a potent and selective 5-HT(4) partial agonist that exhibits efficacy in promoting antral contractions and activity in promoting gastric emptying in canine models. Also discovered were 5-HT(4) receptor antagonists, including imidazopyridine amide 12h (SC-53606), which is a potent and selective 5-HT(4) receptor antagonist with …

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Controlling Charge Injection In Organic Field-Effect Transistors Using Self-Assembled Monolayers, B H. Hamadani, D A. Corley, Jacob W. Ciszek, J M. Tour, D Natelson Jan 2006

Controlling Charge Injection In Organic Field-Effect Transistors Using Self-Assembled Monolayers, B H. Hamadani, D A. Corley, Jacob W. Ciszek, J M. Tour, D Natelson

Chemistry: Faculty Publications and Other Works

We have studied charge injection across the metal/organic semiconductor interface in bottom-contact poly(3-hexylthiophene) (P3HT) field-effect transistors, with Au source and drain electrodes modified by self-assembled monolayers (SAMs) prior to active polymer deposition. By using the SAM to engineer the effective Au work function, we markedly affect the charge injection process. We systematically examine the contact resistivity and intrinsic channel mobility and show that chemically increasing the injecting electrode work function significantly improves hole injection relative to untreated Au electrodes.

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The Hydra Filesystem: A Distrbuted Storage Famework, Benjamin Gonzalez, George K. Thiruvathukal Jan 2006

The Hydra Filesystem: A Distrbuted Storage Famework, Benjamin Gonzalez, George K. Thiruvathukal

Computer Science: Faculty Publications and Other Works

Hydra File System (HFS) is an experimental framework for constructing parallel and distributed filesystems. While parallel and distributed applications requiring scalable and flexible access to storage and retrieval are becoming more commonplace, parallel and distributed filesystems remain difficult to deploy easily and configure for different needs. HFS aims to be different by being true to the tradition of high-performance computing while employing modern design patterns to allow various policies to be configured on a per instance basis (e.g. storage, communication, security, and indexing schemes). We describe a working prototype (available for public download) that has been implemented in the Python …

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Home Networking, George K. Thiruvathukal Jan 2006

Home Networking, George K. Thiruvathukal

Computer Science: Faculty Publications and Other Works

My coeditors (Paul Dubois and Konstantin Läufer) and I are among a growing number of individuals who install and maintain a home computer network. When Paul and I first discussed the idea of writing an article about the subject several months ago, my first thought was that you--our cherished readers-might consider this whole notion so trivial as to not be worthy of a column that focuses mostly on scientific programming and software development topics. But based on the realization that we three computer scientists devote a significant part of our time to network and system administration, it almost goes without …

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