A pilot experiment on affective multiple biosensory mapping for possible application to visual resource analysis and smart urban landscape design

This paper is designed to identify potential stressors as well as negative and positive environmental stimulators in urban landscapes, using wearable physiological sensors and GPS devices. An 8-channeled Procomp Infiniti device was used in this study, recording electrocardiogram (ECG), electroencephalogram (EEG), skin conductance, skin temperature, electromyography (EMG) of facial muscles expression and respiration, with a maximum sample rate at 1024/s. Probands in the pilot experiment were asked to take a 15-minute walk on a designated route for three times. Physiological measures were first filtered and then combined with GPS locations and visual eyesights. Affective mapping analysis based on the collected data allows first conclusions on the responsiveness of probands towards different visual experiences. Further analyses will determine the impacts of urban environments on stressors and what role latest technological advancements in smart landscape design in form of augmented reality can play for improved well-being of city dwellers

Nomarski imaging interferometry to measure the displacement field of MEMS

We propose to use a Nomarski imaging interferometer to measure the out-of-plane displacement field of MEMS. It is shown that the measured optical phase arises both from height and slope gradients. Using four integrating buckets a more efficient approach to unwrap the measured phase is presented, thus making the method well suited for highly curved objects. Slope and height effects are then decoupled by expanding the displacement field on a functions basis, and the inverse transformation is applied to get a displacement field from a measure of the optical phase map change with a mechanical loading. A measurement reproducibility of about 10 pm is achieved, and typical results are shown on a microcantilever under thermal actuation, thereby proving the ability of such a set-up to provide a reliable full-field kinematic measurement without surface modification

Properties of electrons near a Van Hove singularity

The Fermi surface of most hole-doped cuprates is close to a Van Hove singularity at the M point. A two-dimensional electronic system, whose Fermi surface is close to a Van Hove singularity shows a variety of weak coupling instabilities. It is a convenient model to study the interplay between antiferromagnetism and anisotropic superconductivity. The renormalization group approach is reviewed with emphasis on the underlying physical processes. General properties of the phase diagram and possible deformations of the Fermi surface due to the Van Hove proximity are described.Comment: Proceedings of SNS-01 to appear in the Journal of Physics and Chemistry of Solids, SNS-0

De novo ChIP-seq analysis

Methods for the analysis of chromatin immunoprecipitation sequencing (ChIP-seq) data start by aligning the short reads to a reference genome. While often successful, they are not appropriate for cases where a reference genome is not available. Here we develop methods for de novo analysis of ChIP-seq data. Our methods combine de novo assembly with statistical tests enabling motif discovery without the use of a reference genome. We validate the performance of our method using human and mouse data. Analysis of fly data indicates that our method outperforms alignment based methods that utilize closely related species

Plasma coating of carbon nanofibers for enhanced dispersion and interfacial bonding in polymer composites

Ultrathin films of polystyrene were deposited on the surfaces of carbon nanofibers using a plasma polymerization treatment. A small percent by weight of these surface-coated nanofibers were incorporated into polystyrene to form a polymer nanocomposite. The plasma coating greatly enhanced the dispersion of the nanofibers in the polymer matrix. High-resolution transmission-electron-microscopy (HRTEM) images revealed an extremely thin film of the polymer layer (∼3 nm) at the interface between the nanofiber and matrix. Tensile test results showed considerably increased strength in the coated nanofiber composite while an adverse effect was observed in the uncoated composites; the former exhibited shear yielding due to enhanced interfacial bonding while the latter fractured in a brittle fashion. © 2003 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71001/2/APPLAB-83-25-5301-1.pd

Toxic Oligomeric Alpha-Synuclein Variants Present In Human Parkinson’S Disease Brains Are Differentially Generated In Mammalian Cell Models

Misfolding and aggregation of α-synuclein into toxic soluble oligomeric α-synuclein aggregates has been strongly correlated with the pathogenesis of Parkinson’s disease (PD). Here, we show that two different morphologically distinct oligomeric α-synuclein aggregates are present in human post-mortem PD brain tissue and are responsible for the bulk of α-synuclein induced toxicity in brain homogenates from PD samples. Two antibody fragments that selectively bind the different oligomeric α-synuclein variants block this α-synuclein induced toxicity and are useful tools to probe how various cell models replicate the α-synuclein aggregation pattern of human PD brain. Using these reagents, we show that mammalian cell type strongly influences α-synuclein aggregation, where neuronal cells best replicate the PD brain α-synuclein aggregation profile. Overexpression of α-synuclein in the different cell lines increased protein aggregation but did not alter the morphology of the oligomeric aggregates generated. Differentiation of the neuronal cells into a cholinergic-like or dopaminergic-like phenotype increased the levels of oligomeric α-synuclein where the aggregates were localized in cell neurites and cell bodies

Wave function mapping conditions in Open Quantum Dots structures

We discuss the minimal conditions for wave function spectroscopy, in which resonant tunneling is the measurement tool. Two systems are addressed: resonant tunneling diodes, as a toy model, and open quantum dots. The toy model is used to analyze the crucial tunning between the necessary resolution in current-voltage characteristics and the breakdown of the wave functions probing potentials into a level splitting characteristic of double quantum wells. The present results establish a parameter region where the wavefunction spectroscopy by resonant tunneling could be achieved. In the case of open quantum dots, a breakdown of the mapping condition is related to a change into a double quantum dot structure induced by the local probing potential. The analogy between the toy model and open quantum dots show that a precise control over shape and extention of the potential probes is irrelevant for wave function mapping. Moreover, the present system is a realization of a tunable Fano system in the wave function mapping regime.Comment: 6 pages, 6 figure

Effects of surface modification, carbon nanofiber concentration, and dispersion time on the mechanical properties of carbon-nanofiber–polycarbonate composites

The time effect of ultrasonication was investigated for dispersing carbon nanofibers (CNFs) into a polycarbonate (PC) matrix on the mechanical properties of thus-produced composites. The effects of CNF surface modification by plasma treatment and the CNF concentration in composites on their mechanical properties were also explored. The plasma coating was characterized by HRTEM and FT-IR. Furthermore, the plasma polymerization (10 w) treatment on the CNF enhanced the CNF dispersion in the polymer matrix. The mechanical properties of the CNF–PC composites varied with the dispersion time, at first increasing to a maximum value and then dropping down. After a long ultrasonic treatment (24 h), the properties increased again. At a high concentration, the CNF-PC suspension became difficult to disperse. Additionally, the possible mechanisms for these behaviors are simply proposed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3792–3797, 2007Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/55871/1/25112_ftp.pd

Plasma deposition of Ultrathin polymer films on carbon nanotubes

Ultrathin films of pyrrole were deposited on the surfaces of carbon nanotubes using a plasma polymerization treatment. High-resolution electron transmission microscopy images revealed that an extremely thin film of the polymer layer (2 ∼ 7 nm)(2∼7nm) was uniformly deposited on the outer and inner surfaces of the nanotubes. The nanotubes of all sizes exhibited equally uniform ultrathin films, indicating well-dispersed nanotubes in the fluidized bed reactor during the plasma treatment. In particular, the inner wall of the nanotube was also coated with a uniform ultrathin film of only ∼1–3 nm. Time-of-flight secondary ion mass spectroscopy experiments confirmed the highly branched and cross-linked polymer thin films on the carbon nanotubes. The plasma deposition mechanism is discussed in this letter. © 2002 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71075/2/APPLAB-81-27-5216-1.pd