Analyzing GFP-tagged cytoskeletal protein colocalization in human carcinoma cells

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2007.Includes bibliographical references.Cytoskeletal proteins function as dynamic, complex components involved in cellular structure and signaling. Characterizing the roles of such proteins would greatly benefit many research areas, including the study of cancer and protein-related diseases. There is currently no accurate, high throughput method of image analysis that clearly describes protein behavior within the cell. In addressing this problem, we chose to characterize proteins based on the colocalization parameter-the amount of overlap between two objects or signals. We aimed to create a single parameter that quantitatively defined colocalization yet complemented biological intuition about a complicated system. Cell culture techniques were used to transfect HeLa cells with four "marker" GFP-tagged protein constructs. Cells were fluorescently labeled in three channels-Hoechst for nucleus, Texas Red phalloidin for actin, and GFP for protein-and images were captured using Cellomics scanning microscopy. After collecting data and testing software applications, we analyzed our data with Definiens software and developed a flexible, comprehensible method of quantifying colocalization using minimal parameters.by Stephanie M. Reed.S.B

A biased dollar exchange model involving bank and debt with discontinuous equilibrium

In this work, we investigate a biased dollar exchange model with collective debt limit, in which agents picked at random (with a rate depending on the amount of dollars they have) give at random time a dollar to another agent being picked uniformly at random, as long as they have at least one dollar in their pockets or they can borrow a dollar from a central bank if the bank is not empty. This dynamics enjoys a mean-field type interaction and partially extends the recent work \cite{cao_uncovering_2022} on a related model. We perform a formal mean-field analysis as the number of agents grows to infinity and as a by-product we discover a two-phase (ODE) dynamics behind the underlying stochastic $N$-agents dynamics. Numerical experiments on the two-phase (ODE) dynamics are also conducted where we observe the convergence towards its unique equilibrium in the large time limit.Comment: 23 pages, 5 figures. arXiv admin note: substantial text overlap with arXiv:2208.1100

Long-Term Opinion Distributions of an Opinion Formation Model with Averaging Behavior

Sociophysics utilizes mathematical tools from physics to study social phenomena. In particular, interactions between individuals can impact emerging trends in the opinions of a population as a whole. This research focuses on the long-term opinion distributions of a population of individuals who can influence one another through pairwise interactions, where one individual modifies their opinion to be more in line with their neighbor. Interactions are governed by a social network, where friends on the network interact while strangers do not. We introduce a new model for opinion formation with averaging behavior where the opinion of an individual at any time t is an integer between −k and k. For example, an opinion of k could indicate a heavily republican opinion and −k a heavily democratic opinion. As the process evolves in time, interactions between neighbors x and y in the social network result in person x updating her opinion to be one step closer to the opinion of person y. We first consider the scenario where everyone in the social network is friends with everyone else. For k = 1 we compute explicitly the long-term opinion distribution via differential equations. For values of k > 1, we solve for the long-term distribution numerically using Runge-Kutta. We then compute the long-term opinion distribution via simulation, in the more general social network scenario

The relation between college student involvement and satisfaction

The purpose of this study was to examine the relation between college students\u27 involvement and their overall satisfaction with their college experience. It was predicted that the more a student is involved, the more he/she will be satisfied with the college experience. The 60 male and female respondents were traditional students at Anderson University in Anderson, SC. A survey was administered to assess student involvement based on the diversity (types of activities) and amount (hours per week) of participation. Each student\u27s satisfaction with college also was assessed using a self-devised scale. A moderate positive correlation was detected, p\u3c.01, where 12% of the variance in student satisfaction was accounted for by student involvement. The implications and limitations are discussed

Distribution and Habitat Use of the Golden Crab Chaceon fenneri off Eastern Florida Based on In Situ Submersible and ROV Observations and Potential for Impacts to Deep Water Coral/Sponge Habitat

This study documents the distribution and habitat preferences of the golden crab, a commercially fished species, in relation to deep-sea coral/sponge ecosystems (DSCEs) at 200-900 m depths off eastern Florida. A total of 386 h of videotapes from 94 submersible and remotely operated vehicle (ROV) dives from 1999 to 2009, covering a total distance of 376 km, were reviewed and characterized for habitat type and presence of crabs. The DSCEs surveyed included Lophelia coral mounds, Miami Terrace, Pourtalès Terrace, and Tortugas Valleys. Video transect data also included environmental surveys of proposed deep-water routes for Liquid Natural Gas (LNG) pipelines, LNG port, and telecommunications fiber-optic cable. A total of 351 golden crabs (Chaceon fenneri) were counted and observed on a wide variety of habitat types, including coral thickets, rock escarpments, rock pavement, boulders, and soft bottom. The mean density of golden crabs was greater on soft bottom than on hard bottom habitat (0.342±0.234 vs 0.190±0.121 crabs /1000 m2); within the hard bottom regions, mean density was greater on rock substrate than coral substrate (0.206±0.120 and 0.040±0.035 crabs /1000 m2). The current golden crab fishery operates off eastern Florida in Allowable Crab Fishing Areas (ACFAs) within the deep-water Coral Habitat Areas of Particular Concern (CHAPCs); however, we have documented at least 8 regions within the CHAPCs where the ACFAs overlap probable DSCE habitat. Resource managers should adjust the boundaries of the ACFAs to protect and preserve vulnerable DSCE habitat while allowing benthic fisheries to operate in areas of soft bottom habitat