We have developed a hydrogel-based microfluidic device that is capable of generating a steady and long term linear chemical concentration gradient with no through flow in a microfluidic channel. Using this device, we successfully monitored the chemotactic responses of wildtype Escherichia coli (suspension cells) to alpha-methyl-DL-aspartate (attractant) and differentiated HL-60 cells (a human neutrophil-like cell line that is adherent) to formyl-Met-Leu-Phe (f-MLP, attractant). This device advances the current state of the art in microchemotaxis devices in that (1) it demonstrates the validity of using hydrogels as the building material for a microchemotaxis device; (2) it demonstrates the potential of the hydrogel based microfluidic device in biological experiments since most of the proteins and nutrients essential for cell survival are readily diffusible in hydrogel; (3) it is capable of applying chemical stimuli independently of mechanical stimuli; (4) it is straightforward to make, and requires very basic tools that are commonly available in biological labs. This device will also be useful in controlling the chemical and mechanical environment during the formation of tissue engineered constructs.

In a world overflowing with creative works, it is useful to be able to filter out the unimportant works so that the significant ones can be identified and thereby absorbed. An automated method could provide an objective approach for evaluating the significance of works on a universal scale. However, there have been few attempts at creating such a measure, and there are few “ground truths” for validating the effectiveness of potential metrics for significance. For movies, the US Library of Congress’s National Film Registry (NFR) contains American films that are “culturally, historically, or aesthetically significant” as chosen through a careful evaluation and deliberation process. By analyzing a network of citations between 15,425 United States-produced films procured from the Internet Movie Database (IMDb), we obtain several automated metrics for significance. The best of these metrics is able to indicate a film’s presence in the NFR at least as well or better than metrics based on aggregated expert opinions or large population surveys. Importantly, automated metrics can easily be applied to older films for which no other rating may be available. Our results may have implications for the evaluation of other creative works such as scientific research.

The Internet Movie Database (IMDb) is one of the mostvisited websites in the world and the premier source for information on films. Similar to Wikipedia, much of IMDb's information is user contributed. IMDb also allows users to voice their opinion on the quality of films through voting. We investigate whether there is a connection between user voting data and economic film characteristics. We perform distribution and correlation analysis on a set of films chosen to mitigate effects of bias due to the language and country of origin of films. Production budget, box office gross, and total number of user votes for films are consistent with double-log normal distributions for certain time periods. Both total gross and user votes are consistent with a double-log normal distribution from the late 1980s onward while for budget it extends from 1935 to 1979. In addition, we find a strong correlation between number of user votes and the economic statistics, particularly budget. Remarkably, we find no evidence for a correlation between number of votes and average user rating. Our results suggest that total user votes is an indicator of a film's prominence or notability, which can be quantified by its promotional costs.

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