How Do Information and Communication Technologies Reshape Work? Evidence from the Residential Real Estate Industry

We are exploring how information and communication technology (ICT) use affects the work lives of real estate agents, the process of selling/buying houses, and the overall structure of the residential real estate industry. Earlier stages of our work involved intensive field research on how real estate agents use ICT. In this paper, we report on the design and analysis of a pilot survey of 868 agents intended to investigate their ICT use more generally. Analysis of the 153 responses to this survey sheds light on how ICT use supports information control, enables process support, and helps agents to extend and maintain their social capital

Use of micellar electrokinetic chromatography to measure palmitoylation of a peptide

Palmitoylation is the thioester linkage of the fatty acid, palmitate (C16:0), to cysteine residues on a protein or peptide. This dynamic and reversible post-translational modification increases the hydrophobicity of proteins/peptides, facilitating protein-membrane interactions, protein-protein interactions and intracellular trafficking of proteins. Manipulation of palmitoylation provides a new mechanism for control over protein location and function, which may lead to better understanding of cell signaling disorders, such as cancer. Unfortunately, few methods exist to quantitatively monitor protein or peptide palmitoylation. In this study, a capillary electrophoresis-based assay was developed, using MEKC, to measure palmitoylation of a fluorescently-labeled peptide in vitro. A fluorescently-labeled peptide derived from the growth-associated protein, GAP-43, was palmitoylated in vitro using palmitoyl coenzyme A. Formation of a doubly-palmitoylated GAP-peptide product was confirmed by mass spectroscopy. The GAP-peptide substrate was separated from the palmitoylated peptide product in under 7 minutes by MEKC. The rate of in vitro palmitoylation with respect to reaction time, GAP-peptide concentration, pH, and inhibitor concentration were also examined. This capillary electrophoresis-based assay for monitoring palmitoylation has applications in biochemical studies of acyltransferases and thioesterases as well as in the screening of acyltransferase and thioesterase inhibitors for drug development

An Integrated Chemical Cytometry Method: Shining a Light on Akt Activity in Single Cells

Tools to evaluate oncogenic kinase activity in small clinical samples have the power to guide precision medicine in oncology. Existing platforms have demonstrated impressive insights into the activity of protein kinases, but these technologies are unsuitable for the study of kinase behavior in large numbers of primary human cells. To address these limitations, we developed an integrated analysis system which utilizes a light-programmable, cell-permeable reporter deliverable en masse to many cells. The reporter's ability to act as a substrate for Akt, a key oncogenic kinase, was masked by a 2-4,5-dimethoxy 2-nitrobenzyl (DMNB) moiety. Upon exposure to ultraviolet light and release of the masking moiety, the substrate sequence enabled programmable reaction times within the cell cytoplasm. When coupled to automated single-cell capillary electrophoresis, statistically significant numbers of primary human cells were readily evaluated for Akt activity

The role of calcium in the destruction of target cells by cytotoxic T cells

Thesis (Ph. D.)--Massachusetts Institute of Technology, Harvard-MIT Divison of Health Sciences and Technology Program in Medical Engineering and Medical Physics, 1987.Title as it appears in M.I.T. Graduate List, June 1987: The role of calcium in the destruction of target cells by cytotoxic T lymphocytes.Bibliography: leaves 224-239.by Nancy L. Allbritton.Ph.D

Gradation of Porcine Bladder ECM in Hydrogels for Chronic Wound Treatment

Chronic, nonhealing wounds affect about 6.5 million individuals in the U.S., and often present as comorbidities of other prevalent conditions such as obesity and diabetes. Chronic wounds are characterized by a recurring inflammatory state without progression to the proliferation and remodeling stages of wound healing. Around $25 billion is spent annually on treatment of chronic wounds; however most traditional wound care approaches do not effectively encourage the physiological healing process. One emerging treatment option is extracellular matrix (ECM)-based wound dressings, which are composed of a network of proteins and other macromolecules that support and anchor cells within tissue. These dressings are typically composed of decellularized tissue derived from animal donors and provide a protein scaffold that mimics dermal ECM by facilitating cell adhesion. Most commercially available ECM-based dressings are dry, uniform sheets of ECM that provide a structural scaffold for cellular growth, but do not provide a physiologically relevant moisture balance or encourage cellular infiltration into the dressing as the wound heals. However, fibroblasts, which play a major role in wound healing, have been shown to migrate to regions of denser ECM concentrations, where they exhibit enhanced metabolic activity and proliferation. A UBM-based hydrogel will serve as an alternative wound dressing that will mitigate the issues with current ECM-based products. A hydrogel dressing offers a more physiologically relevant moisture balance to the site of the wound, while integrated structural cues will encourage fibroblast infiltration. Ultimately, this approach will increase the rate at which ulcers heal and prevent further deterioration of the wound site, in turn lessening the physical and financial burden on patients.Maryland Summer Scholars 201

In situ Roughening of Polymeric Microstructures

A method to perform in-situ roughening of arrays of microstructures weakly adherent to an underlying substrate was presented. SU8, 1002F, and polydimethylsiloxane (PDMS) microstructures were roughened by polishing with a particle slurry. The roughness and the percentage of dislodged or damaged microstructures was evaluated as a function of the roughening time for both SU8 and 1002F structures. A maximal RMS roughness of 7-18 nm for the surfaces was obtained within 15 to 30 s of polishing with the slurry. This represented a 4-9 fold increase in surface roughness relative to that of the native surface. Less than 0.8% of the microstructures on the array were removed or damage after 5 min of polishing. Native and roughened arrays were assessed for their ability to support fibronectin adhesion and cell attachment and growth. The quantity of adherent fibronectin was increased on roughened arrays by two-fold over that on native arrays. Cell adhesion to the roughened surfaces was also increased compared to native surfaces. Surface roughening with the particle slurry also improved the ability to stamp molecules onto the substrate during microcontact printing. Roughening both the PDMS stamp and substrate resulted in up to a 20-fold improvement in the transfer of BSA-Alexa Fluor 647 from the stamp to the substrate. Thus roughening of micron-scale surfaces with a particle slurry increased the adhesion of biomolecules as well as cells to microstructures with little to no damage to large scale arrays of the structures

Effect of the DEF motif on phosphorylation of peptide substrates by ERK

MAP kinase ERK maintains specificity by binding to docking sites such as the DEF domain or D domain. It was previously shown that appending peptides derived from D domains to a substrate peptide increased apparent efficiency of peptide phosphorylation while preserving its apparent specificity for ERK. Here we determine the effect of the DEF motif on efficiency and specificity of peptide phosphorylation by ERK. The DEF motif modulated the apparent affinity of the peptide for ERK while the substrate motif dominated the apparent catalytic rate. Attachment of the DEF sequence improved apparent phosphorylation efficiency by 60-fold. Addition of peptides possessing both the DEF and D motif to a substrate sequence did not yield additive effects on the KM of the substrate for ERK. Further, the DEF motif diminished the apparent specificity for ERK and increased the apparent efficiencies of phosphorylation of the substrate peptide by p38α kinase and JNK1