archives@tulane.edu / We have developed a laser-biomaterial interaction-based prototyping platform capable of three fabrication modes: (1) laser direct write of cells, microbeads, and other biomaterials; (2) fabrication of cell encapsulating microspheres (microcapsules); and (3) laser micromachining of substrates. Using this system, we are able to precisely place biomaterials, such as cells, into substrates with spatial constraints from laser micromachining or wholly fabricate scaffolds that are cell laden. This enables fabrication of cocultures in almost any geometry and controlled gradients of chemical factors. In addition, the process is parallelizable, thus allowing for numerous potential bioassay applications. One such assay is a differential system for quantifying multiple outcomes in response to multiple parallel biophysicochemical cues in competition. These novel assays are complex, reproducible, and disposable microenvironments. This document will summarize the control integration developed for Laser Direct Write, a 2D model of laser ablation, with a computational method demonstrating preliminary results. Finally the biofabrication methods discussed are applied to an Organ-on-a-Chip model to develop a fully automated fabrication process. / 1 / samuel sklare

The purpose of the present study was to investigate response allocation amongst two concurrently available computerized slot machines, one dispensing Losses Disguised as Wins (LDWs) while the other did not. Both payouts were equal in the beginning and became consistently worst for the LDW machine by lowering the payout each phase. LDWs are slot machine outcomes, participants bet on a slot machine and win back less than their wager. This may be a problem because participants may react to LDWs as a win, misleading the participant to think they are winning more than they actually are. In the present study the LDW outcome payout started at 80 percent payback and decrease by 20 percent each phase and non LDW, maintained at 400 percent payback over 12 percent of the trials. Twenty individuals were recruited by the researcher. Results indicated that a higher percentages of spins were allocated to the machine dispensing LDW. These results suggest that gamblers have a preference for LDW machines because of the reinforcement of the misleading factors that may indicated a win. Keywords: Gambling, LDW, slot machine, visual basic

Negative expected values typically define the behavior of gambling whereby a person risks more money than probabilistically will be returned. Modern slot machines represent the most popular topography of site gambling, and are thought to encourage irrational gambling behaviors through the presentation of outcome stimuli that occasion the gambler to inaccurately detect the programmed contingencies. One recently added characteristic of modern slot machines is the ability to deliver wins with lower magnitudes of credits than the initially staked wagers. Termed a "loss disguised as a win" (LDW), this type of consequence appears to produce reinforcement effects despite representing an overall loss of credits. In a series of three experiments using computer simulated slot machines, the presentation of LDWs were initially evaluated for possible influence on the temporal characteristics of repeated wagers, subsequently examined to potentially bias response allocation across concurrently available LDW display densities, and finally appraised after discrimination training designed to potentially alter the discriminative and consequential functions of LDWs. Treatment implications and directions for future research are discussed.

Post-reinforcement pause was examined to determine the reinforcing value of a win, loss, and a loss disguised as a win (LDW) for gamblers at multi-line video slot machines. The study was conducted in naturalistic settings across a variety of participants, age 21 years and older. The length of the post-reinforcement pause was recorded using a stopwatch for one win, one loss, and one LDW for each participant and was measured by recording the time between the outcome delivery and the initiation of the next spin. The different times were evaluated to determine which of the three resulted in the longest post-reinforcement pause for the gamblers following the slot machine outcome. The present study replicates and extends previous research on post-reinforcement pause in slot machine gambling, and provides discussion around the clinical utility of such findings on the prevention of problem gambling. Problem gambling is an epidemic, and there are numerous variables that contribute to its development. Post-reinforcement pause is one for those factors, and the present study can help us gain a better understanding of the events that maintain problem gambling and ways to prevent it. The results of the present study found that wins are the most reinforcing to gamblers compared to LDWs and losses, and that LDWs are significantly more reinforcing to gamblers than losses, as indicated by the patterns of the post-reinforcement pause.