Interspecies Tissue Transplants in Planarians

Planarian flatworms have many stem cells called neoblasts which makes them adept at regenerating tissue after injury. This project aims to determine if neoblasts from two different species of planarians—Schmidtea mediterranea and Dugesia japonica—can integrate into the regenerated tissue of the other species. This is done by transplantation of a donor tissue plug from one species into a host planarian of the opposite species. After the host planarian is injured, neoblasts travel to the site of injury and begin regeneration of tissue. We have worked to optimize the transplantation procedure to visually obtain a 75% success rate. Simultaneously, we have begun to attempt to optimize a protocol for colorimetric in situ hybridization that gives optimal staining of neoblasts for both species so that we will be able to determine which neoblasts from which species are involved in regeneration following injury.https://digitalcommons.snc.edu/collaborative_presentations/1067/thumbnail.jp

Functional Characterization and Surface Mapping of Frataxin (FXN) Interactions with the Fe-S Cluster Assembly Complex

In 1996, scientists discovered a connection between the gene for the human protein frataxin (FXN) and the neurodegenerative disease Friedreich’s ataxia (FRDA). Decreased FXN levels result in a variety of aberrant phenotypes including loss of activity for iron-sulfur containing enzymes, mitochondrial iron accumulation, and susceptibility to oxidative stress. These symptoms are the primary focus of current therapeutic efforts. In contrast our group is pursuing an alternate strategy of first defining FXN function at a molecular level then using this information to identify small molecule functional replacements. Recently, our group has discovered that FXN functions as an allosteric activator for the human Fe-S cluster assembly complex. The work presented here helps to further define molecular details of FXN activation and explain how FRDA missense mutants are functionally compromised. First, the FRDA missense mutants L182H and L182F were investigated. Unlike other characterized FRDA missense mutants, the L182F variant was not compromised in its ability to bind and activate the Fe-S assembly complex. The L182H variant exhibited an altered circular dichroism signature; suggesting a change in secondary structure relative to native FXN, and rapidly degraded. Together these studies suggest that L182 variants are less stable than native FXN and are likely prone to degradation in FRDA patients. Second, as a regulatory role of FXN suggests that its function is likely controlled by environmental stimuli, different maturation forms of FXN as well as post-translational modification mimics were tested as mechanisms to control FXN regulation. Here experiments were designed to test if a larger polypeptide form of FXN represents a functional form of the protein. Kinetic and analytical ultracentrifugation studies revealed a complex heterogeneous mixture of species some of which can activate the Fe-S assembly complex. A previously identified acetylation site was also tested using mutants that mimic acetylation. These mutants had little effect on the ability of FXN to bind and activate the assembly complex. Third, mutagenesis experiments were designed in which the FXN surface residues were replaced with alanine and the resulting variants were tested in binding and activity assays. These experiments revealed a localized “hot-spot” on the surface of FXN that suggests small cyclic peptide mimics might be able to replace FXN and function as FRDA therapeutics. Unexpectedly, one of the FXN variants exhibited significantly tighter binding and could have relevance for therapeutic development

Cognitive bias in large language models: Cautious optimism meets anti-Panglossian meliorism

Traditional discussions of bias in large language models focus on a conception of bias closely tied to unfairness, especially as affecting marginalized groups. Recent work raises the novel possibility of assessing the outputs of large language models for a range of cognitive biases familiar from research in judgment and decisionmaking. My aim in this paper is to draw two lessons from recent discussions of cognitive bias in large language models: cautious optimism about the prevalence of bias in current models coupled with an anti-Panglossian willingness to concede the existence of some genuine biases and work to reduce them. I draw out philosophical implications of this discussion for the rationality of human cognitive biases as well as the role of unrepresentative data in driving model biases

Numerical study on splash zone crossing with GRP protection cover.

For oil and gas fields moving further offshore, it has been more common to use a subsea production system or a combination of rig and subsea structures. These subsea structures must be overtrawlable if they are not marked with a buoy or vessel. One solution for overtrawlable subsea structures is to use a protection cover. This study focuses on GRP pipeline protection covers, which are highly weather-sensitive due to their low weight and large surface area. Installation of subsea protective covers typically involves overboard, lowering through the splash zone, and lowering to the seabed. This study will focus on the lowering through the splash zone, which is usually considered one of the most critical phases of a deployment operation. The hydrodynamic property for the cover is calculated based on DNV-RP-H103 simplified methods [1]. The vessel’s properties are collected with a diffraction analysis program that calculates the responses and loading for wet bodies using potential flow theory. Hence, body results are generated for: damping, added mass, displacement RAOs, and load RAOs. In addition, the calculated pressure in the fluid will yield the sea state RAOs for the fluid pressure. The vessel was then implemented into the numerical time-domain program with the cover. For the numerical methods, two sensitivity studies are conducted to evaluate the number of wave seeds and vessel motion to be applied to assess sea states. First, the numbers of seeds selected were based on the extreme values for the sling tension. Then, analyzing the extreme values with a statistical method and the cumulative average for minimum and maximum tension. The extracted results indicated that 30 seeds were enough to yield reliable predictions of the sea states. The same procedure was applied for the vessel motion as for the number of wave seeds. In addition, the simulation demo file was closely investigated to observe any differences between the motions. From the extracted extreme values, the difference between the motion where slightly more conservative for the coupled motion. However, the uncoupled vessel motion was selected to assess the allowable sea states. The uncoupled motion would better represent the real-life, where for the coupled vessel it was observed large yaw motions for longer wave periods In the assessment of the sea states, three simulation cases were selected to investigate the hydrodynamic forces during the splash zone crossing. Firstly, the different lifting angles of the cover made it possible to adjust the waterplane area. Secondly, evaluate the vessel position for wave directions of 165 and 180 degrees. Lastly, use the vessel to disrupt the incoming waves generating a shielding effect for the cover. Concerning the operational criteria, the extreme values were fitted to a Gumbel probability paper to assess the allowable sea states. The results indicated that the shielding effect on the cover would yield the best applicable sea states for all tested methods. For the different tested lifting angles of the cover. The cover with the lowest waterplane area resulted in the highest sea states due to lower hydrodynamic forces on the cover. Lastly, for the two tested wave directions. The vessel for head waves yielded slightly better allowable sea states. The increased roll motion for the wave direction at 165 degrees resulted in larger slamming loads and lower sling tensions for the cover

The Historical and Cultural Geography of the Grange in Minnesota and Louisiana, 1870-1880.

This study uses historical and geographical inquiry to examine postbellum agrarian social, political and economic unrest that in 1868 led to the formation of the first national, secret and ritualistic, fraternal agricultural society known as the Grange. The Grange was created to unite farmers through cooperative buying and selling, to promote agricultural education, and to create a social organization that encouraged both women and men to acquire and refine leadership skills. It also sought to address concerns over monopolies and promoted state regulation of railroad rates. Although Grange membership peaked in 1875 and sharply declined through 1880, it forged the way for more radical rural organizations and reform movements such as the Farmers\u27 Alliance (1880s) and The Populist Party (1890s). The dissertation focuses on the socioeconomic composition and geographic distribution of Grange charter members within the states of Minnesota and Louisiana during the society\u27s initial period of organization and growth (1870--1880). Data were compiled and analyzed on Minnesota and Louisiana Subordinate Grange chapter locations, their diffusion, and certain economic attributes of charter members. Statistical tests highlighted the differences between non-Grange farmers and Grangers within and between the two states. Grangers in both states benefitted from networking . At monthly Grange meetings, educational lectures on the best methods and practices of farming, home keeping skills or economics were given and agricultural subjects were discussed. These meetings also provided the members with a sense of fraternity and community. Social, political and economic conditions were far better in Minnesota than in Louisiana during the period 1870--1880. In Minnesota, the Grange grew, prospered and remained a viable organization beyond the years of this study. Minnesota Grangers: enjoyed economic advantages over non-Grange farmers thanks to their capital investments in land and machinery which led to increased production of wheat and corn and higher values of all farm production. In Louisiana, the organization arrived late, floundered and met its demise by the early 1880s. Louisiana Grangers fared slightly better economically than their non-Grange counterparts between 1870 and 1880, but they suffered economic losses on every variable tested except the production of corn

Recommendations on size and position of surgically and gastrically implanted electronic tags in European silver eel

Background: Information on European silver eel Anguilla anguilla anatomy was collected to gain information on limitations on size and placement of electronic tags. Findings: To reduce the eel’s ability to bite its own sutures, it may be an advantage to make surgical incisions close to the head, but this increases the risk of cutting the liver. Recommended placement of an incision was slightly further from the head than one-fourth of the fish’s body length (LT) to avoid damaging the liver. Long, flexible tags comprising various components can be adjusted to the narrow body cavity and undulating movements of eels. There was space for surgically implanting a 100 mm long tag (11 mm in diameter) in the body cavity of eels with LT ≥380 mm. During gastric tagging, tag length is limited by stomach length. Silver eels with LT 380 to 998 mm had stomach lengths of 47 to 185 mm, indicating that there was space for short gastric tags in the smallest eels, but that there was space for relatively long tags in larger eels. The distance from the snout to the start of the stomach constituted 15 to 23% of LT, indicating how far the transmitter should be inserted during tagging. Conclusion: This information aids the development of tags and tagging methods that consider the unique morphological and behavioral features of eels. Keywords: Intraperitoneal implantation, Intragastric insertion, Tagging, Transmitter, Telemetry, Tagging effectRecommendations on size and position of surgically and gastrically implanted electronic tags in European silver eelpublishedVersio