Tubular structures such as blood vessels, intestines, and the trachea are common in various life forms. This paper describes a measurement system to test the mechanical compliance of tubular structures. The novelty of the system lies in its hardware and software. Here we use vascular graft as an example to demonstrate the utility of the system. A fully synthetic vascular graft would ideally mimic the mechanical and architectural properties of a native blood vessel. Therefore, mechanical testing of the graft material under physiological pressure is crucial to characterizing its potential in vivo performance. The device operates through a low-cost Arduino-based control system that simulates and measures cyclic fluid pressure changes over time and a laser micrometer that measures diameter changes with pressure. This system is low-cost, assuming one already has access to a laser micrometer. In contrast to previous methods, this system offers a simple, low-cost, and customizable option to measure compliance and is equipped with data acquisition/analysis programs. These programs include a MATLAB application that processes and synchronizes Arduino Uno pressure signals and LabChart Pro diameter readings. Lastly, this paper explains the hardware and software of the measurement system. The system is beneficial for testing the pressure-diameter relationship of tubular structures of varying sizes and materials. KEYWORDS: Tubular Structures; Compliance; Data Acquisition System; Physiological Pressure; Diameter Change; Arduino Uno; LabChart Pro; MATLAB
血管、肠道和气管等管状结构在各种生命形式中都很常见。本文介绍了一种测试管状结构机械顺应性的测量系统。该系统的新颖之处在于其硬件和软件。在此，我们以血管移植为例，展示该系统的实用性。理想情况下，全合成血管移植物能模拟原生血管的机械和结构特性。因此，在生理压力下对移植物材料进行机械测试对于鉴定其潜在的体内性能至关重要。该装置通过一个基于 Arduino 的低成本控制系统运行，该系统可模拟和测量随时间变化的循环流体压力变化，而激光测微计则可测量直径随压力的变化。该系统成本低廉，假设人们已经有了激光测微计。与之前的方法相比，该系统提供了一种简单、低成本、可定制的测量顺应性的方法，并配备了数据采集/分析程序。这些程序包括一个 MATLAB 应用程序，用于处理和同步 Arduino Uno 压力信号和 LabChart Pro 直径读数。最后，本文介绍了测量系统的硬件和软件。该系统有利于测试不同尺寸和材料的管状结构的压力-直径关系。关键词： 管状结构；顺应性；数据采集系统；生理压力；直径变化；Arduino Uno；LabChart Pro；MATLAB
{"title":"Measurement System for Compliance in Tubular Structures","authors":"Ave Kludze, Anthony D’Amato, Yadong Wang","doi":"10.33697/ajur.2024.106","DOIUrl":"https://doi.org/10.33697/ajur.2024.106","url":null,"abstract":"Tubular structures such as blood vessels, intestines, and the trachea are common in various life forms. This paper describes a measurement system to test the mechanical compliance of tubular structures. The novelty of the system lies in its hardware and software. Here we use vascular graft as an example to demonstrate the utility of the system. A fully synthetic vascular graft would ideally mimic the mechanical and architectural properties of a native blood vessel. Therefore, mechanical testing of the graft material under physiological pressure is crucial to characterizing its potential in vivo performance. The device operates through a low-cost Arduino-based control system that simulates and measures cyclic fluid pressure changes over time and a laser micrometer that measures diameter changes with pressure. This system is low-cost, assuming one already has access to a laser micrometer. In contrast to previous methods, this system offers a simple, low-cost, and customizable option to measure compliance and is equipped with data acquisition/analysis programs. These programs include a MATLAB application that processes and synchronizes Arduino Uno pressure signals and LabChart Pro diameter readings. Lastly, this paper explains the hardware and software of the measurement system. The system is beneficial for testing the pressure-diameter relationship of tubular structures of varying sizes and materials. KEYWORDS: Tubular Structures; Compliance; Data Acquisition System; Physiological Pressure; Diameter Change; Arduino Uno; LabChart Pro; MATLAB","PeriodicalId":72177,"journal":{"name":"American journal of undergraduate research","volume":"79 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140360238","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Artificial Intelligence (AI) tools recently became a prominent concern in higher education classrooms. Many teachers have implemented the technology into their assignments, while others are strictly against this technology’s use for assignments. Either way, students have found ways to use it in their academic careers. Though research on the power of AI in the workplace exists, research is lacking in its appropriate use in higher education. Universities need to define AI’s role on campus and establish guidelines on how these tools may or may not be used and how faculty can recognize misuse, specifically related to academic integrity. This study aimed to determine how faculty view AI as a part of undergraduate literature, language, and linguistics programs. From the interview study, common themes emerged, including implementation, academic integrity, the human aspect of linguistics, and the future of AI writing tools. Interviewed faculty also stated that those in higher education must tread carefully through this strong intersection between technology and the arts to use AI responsibly, strategically, and ethically. KEYWORDS: Artificial Intelligence (AI); Artificial General Intelligence (AGI); Linguistics; Higher Education; ChatGPT; Machine Translation; Academic Integrity; Ethics
{"title":"Faculty Opinions of AI Tools: Text Generators and Machine Translators","authors":"Mahlet Yitages, Akie Kasai","doi":"10.33697/ajur.2024.102","DOIUrl":"https://doi.org/10.33697/ajur.2024.102","url":null,"abstract":"Artificial Intelligence (AI) tools recently became a prominent concern in higher education classrooms. Many teachers have implemented the technology into their assignments, while others are strictly against this technology’s use for assignments. Either way, students have found ways to use it in their academic careers. Though research on the power of AI in the workplace exists, research is lacking in its appropriate use in higher education. Universities need to define AI’s role on campus and establish guidelines on how these tools may or may not be used and how faculty can recognize misuse, specifically related to academic integrity. This study aimed to determine how faculty view AI as a part of undergraduate literature, language, and linguistics programs. From the interview study, common themes emerged, including implementation, academic integrity, the human aspect of linguistics, and the future of AI writing tools. Interviewed faculty also stated that those in higher education must tread carefully through this strong intersection between technology and the arts to use AI responsibly, strategically, and ethically. KEYWORDS: Artificial Intelligence (AI); Artificial General Intelligence (AGI); Linguistics; Higher Education; ChatGPT; Machine Translation; Academic Integrity; Ethics","PeriodicalId":72177,"journal":{"name":"American journal of undergraduate research","volume":"24 24","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140358529","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Claire Behning, Lia Kelly, Emma Smith, Yizhe Ma, Louis Roberts
Collagen is a functional biomaterial with many applications, including wound healing. 3D collagen hydrogels mimic an in vivo cell culture experience used in cell survival and growth studies. In experimentally examining human cells under contact with 3D collagen, it is possible to understand the role of collagen in human epithelial tissue repair. This study explored the growth and attachment response of human MCF-7 cells when exposed to 3D collagen by investigating if the presence of NIH/3T3 fibroblasts embedded within the collagen should produce an increased wound-healing response. 3D collagen and fibroblast presence were able to be analyzed in tandem with a “sandwich-like” configuration of the gels to determine how these variables impact or improve the tissue repair response in MCF-7 cells. Examinations in growth, attachment, viability, and migration patterns demonstrated that MCF-7 repair response may be increased when in contact with NIH/3T3 embedded 3D collagen without impairing viability. Most notably, results from the migration assay revealed that MCF-7 cells migrate the most when covered by and adhered to cellular 3D collagen. Fibroblast-embedded collagen on top of and below MCF-7 cells exceeded quantitative assessment to near confluency, whereas less than 50 counted cells per image migrated without any top collagen layering. The continuation of these methods could involve in vivo experiments that incorporate live animal models to determine if these results will continue to extend to live tissue. KEYWORDS: Collagen; 3D Collagen; Fibroblasts; Wound Healing; Hydrogels; Tissue Repair; Migration
{"title":"Fibroblast Embedded 3D Collagen as a Potential Tool for Epithelial Wound Repair","authors":"Claire Behning, Lia Kelly, Emma Smith, Yizhe Ma, Louis Roberts","doi":"10.33697/ajur.2023.107","DOIUrl":"https://doi.org/10.33697/ajur.2023.107","url":null,"abstract":"Collagen is a functional biomaterial with many applications, including wound healing. 3D collagen hydrogels mimic an in vivo cell culture experience used in cell survival and growth studies. In experimentally examining human cells under contact with 3D collagen, it is possible to understand the role of collagen in human epithelial tissue repair. This study explored the growth and attachment response of human MCF-7 cells when exposed to 3D collagen by investigating if the presence of NIH/3T3 fibroblasts embedded within the collagen should produce an increased wound-healing response. 3D collagen and fibroblast presence were able to be analyzed in tandem with a “sandwich-like” configuration of the gels to determine how these variables impact or improve the tissue repair response in MCF-7 cells. Examinations in growth, attachment, viability, and migration patterns demonstrated that MCF-7 repair response may be increased when in contact with NIH/3T3 embedded 3D collagen without impairing viability. Most notably, results from the migration assay revealed that MCF-7 cells migrate the most when covered by and adhered to cellular 3D collagen. Fibroblast-embedded collagen on top of and below MCF-7 cells exceeded quantitative assessment to near confluency, whereas less than 50 counted cells per image migrated without any top collagen layering. The continuation of these methods could involve in vivo experiments that incorporate live animal models to determine if these results will continue to extend to live tissue. KEYWORDS: Collagen; 3D Collagen; Fibroblasts; Wound Healing; Hydrogels; Tissue Repair; Migration","PeriodicalId":72177,"journal":{"name":"American journal of undergraduate research","volume":"21 10","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140359241","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study examines first what type of evidence is most influential in online discussions for patients when making decisions about their health and second how people deploy, interpret, and react to stories in these online discussions to better understand the role and importance of narrative in the medical field. Data was gathered on the platform Reddit using the subreddit r/melanoma for a duration of two weeks. 242 posts were collected and analyzed. Using a combination of grounded theory and coding criteria from sociologist and narrative scholar Francesca Polletta, a code book was developed and applied to all 242 posts to assess narrative impact and engagement. Results demonstrate that evidence based on past experiences and factual information were the most persuasive. Additionally, stories yielded greater discussion, greater empathetic connections, and greater positive responses from online discussants than other forms of evidence. Further, those positive responses indicate that patients seeking medical advice were more likely to express agreement with the advice when it was offered with a story. Given these results, greater attention should be paid to narratives shared in online communities, particularly considering the levels of misinformation and disinformation found online and the evolving relationships between doctors and patients where authority is no longer so easily assumed. KEYWORDS: Narrative; Personal Experience; Fact; Evidence; Persuasion; Medical Decision-Making; Social Media
{"title":"The Impact of Narratives on Healthcare Decision-Making in Online Discourse","authors":"Zayd Almaya, Tom Mould","doi":"10.33697/ajur.2024.104","DOIUrl":"https://doi.org/10.33697/ajur.2024.104","url":null,"abstract":"This study examines first what type of evidence is most influential in online discussions for patients when making decisions about their health and second how people deploy, interpret, and react to stories in these online discussions to better understand the role and importance of narrative in the medical field. Data was gathered on the platform Reddit using the subreddit r/melanoma for a duration of two weeks. 242 posts were collected and analyzed. Using a combination of grounded theory and coding criteria from sociologist and narrative scholar Francesca Polletta, a code book was developed and applied to all 242 posts to assess narrative impact and engagement. Results demonstrate that evidence based on past experiences and factual information were the most persuasive. Additionally, stories yielded greater discussion, greater empathetic connections, and greater positive responses from online discussants than other forms of evidence. Further, those positive responses indicate that patients seeking medical advice were more likely to express agreement with the advice when it was offered with a story. Given these results, greater attention should be paid to narratives shared in online communities, particularly considering the levels of misinformation and disinformation found online and the evolving relationships between doctors and patients where authority is no longer so easily assumed. KEYWORDS: Narrative; Personal Experience; Fact; Evidence; Persuasion; Medical Decision-Making; Social Media","PeriodicalId":72177,"journal":{"name":"American journal of undergraduate research","volume":"46 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140360475","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Antibiotic resistance is one of the world’s fastest-growing and most prevalent problems today. The influx of antibiotics within our environment from inadequate antibiotic stewardship has led to a surge of drug-resistant microorganisms. The CDC has classified Carbapenem-resistant Acinetobacter (CRA) as an urgent threat within this crisis. New drug development is imperative to combat infections caused by drug-resistant pathogens such as CRA. Bacterial translation, the process of protein synthesis by the ribosome, is a common target for new antibiotic development. Elongation factor P (EF-P) is a universally conserved translation factor required for antibiotic resistance in many bacteria. In this study, we assessed the importance of EF-P in processes associated with Acinetobacter pathogenesis. In the absence of EF-P, Acinetobacter baylyi displays decreased biofilm formation, surface-associated motility, and resistance to beta-lactams and carbapenems. This data holds hope for future drug development targeting EF-P in pathogens closely related to A. baylyi. KEYWORDS: Acinetobacter baylyi; Translation; Ribosome; Elongation Factor P; Polyproline; Biofilm; Surface Associated Motility; Antibiotic Resistance
{"title":"Elongation Factor P is Required for Processes Associated with Acinetobacter Pathogenesis","authors":"Dylan Kostrevski, Anne Witzky","doi":"10.33697/ajur.2024.105","DOIUrl":"https://doi.org/10.33697/ajur.2024.105","url":null,"abstract":"Antibiotic resistance is one of the world’s fastest-growing and most prevalent problems today. The influx of antibiotics within our environment from inadequate antibiotic stewardship has led to a surge of drug-resistant microorganisms. The CDC has classified Carbapenem-resistant Acinetobacter (CRA) as an urgent threat within this crisis. New drug development is imperative to combat infections caused by drug-resistant pathogens such as CRA. Bacterial translation, the process of protein synthesis by the ribosome, is a common target for new antibiotic development. Elongation factor P (EF-P) is a universally conserved translation factor required for antibiotic resistance in many bacteria. In this study, we assessed the importance of EF-P in processes associated with Acinetobacter pathogenesis. In the absence of EF-P, Acinetobacter baylyi displays decreased biofilm formation, surface-associated motility, and resistance to beta-lactams and carbapenems. This data holds hope for future drug development targeting EF-P in pathogens closely related to A. baylyi. KEYWORDS: Acinetobacter baylyi; Translation; Ribosome; Elongation Factor P; Polyproline; Biofilm; Surface Associated Motility; Antibiotic Resistance","PeriodicalId":72177,"journal":{"name":"American journal of undergraduate research","volume":"120 9","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140359846","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Block bootstrap is widely used in constructing confidence intervals for parameters estimated from stationary time series. Theoretically, the method should provide valid confidence intervals as the length of the time series goes to infinity. In practice, however, it is necessary to know how large of a finite sample is required for block bootstrap confidence intervals to work well. This study aims to answer this question in a simple simulation setting where the data are generated from a first-order autoregressive process. The empirical coverage rates of several commonly used bootstrap confidence intervals for the mean, standard deviation, and the lag-1 autocorrelation coefficient are compared. A quite large sample is found necessary for the intervals to have the right coverage rates even when estimating a simple parameter like the mean. Some block bootstrap methods could fail when estimating the lag-1 autocorrelation. It is surprising that the coverage property even deteriorates as the sample size increases with some commonly used block bootstrap confidence intervals including the percentile intervals and bias-corrected intervals. KEYWORDS: Autocorrelation; Bias-Correction; Centering; Dependent Data; Percentile; Resampling; Simulation; Time Series
{"title":"On Sample Size Needed for Block Bootstrap Confidence Intervals to Have Desired Coverage Rates","authors":"Mathew Chandy, Elizabeth Schifano, Jun Yan","doi":"10.33697/ajur.2024.101","DOIUrl":"https://doi.org/10.33697/ajur.2024.101","url":null,"abstract":"Block bootstrap is widely used in constructing confidence intervals for parameters estimated from stationary time series. Theoretically, the method should provide valid confidence intervals as the length of the time series goes to infinity. In practice, however, it is necessary to know how large of a finite sample is required for block bootstrap confidence intervals to work well. This study aims to answer this question in a simple simulation setting where the data are generated from a first-order autoregressive process. The empirical coverage rates of several commonly used bootstrap confidence intervals for the mean, standard deviation, and the lag-1 autocorrelation coefficient are compared. A quite large sample is found necessary for the intervals to have the right coverage rates even when estimating a simple parameter like the mean. Some block bootstrap methods could fail when estimating the lag-1 autocorrelation. It is surprising that the coverage property even deteriorates as the sample size increases with some commonly used block bootstrap confidence intervals including the percentile intervals and bias-corrected intervals. KEYWORDS: Autocorrelation; Bias-Correction; Centering; Dependent Data; Percentile; Resampling; Simulation; Time Series","PeriodicalId":72177,"journal":{"name":"American journal of undergraduate research","volume":"11 13","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140358991","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This project aims to solve the structure of the crenarchaeal Sulfolobus acidocaldarius enzyme malate synthase. Other known malate synthase enzymes have been found to require a magnesium ion in the active site to carry out catalytic activities, but a study reported that S. acidocaldarius malate synthase does not require magnesium. This suggests a novel mechanism for this enzyme. Additionally, the mature S. acidocaldarius protein is approximately 100 residues larger than any other structurally characterized malate synthase. It has also been reported to form a dimer, while previously solved structures have only displayed monomeric, trimeric, and hexameric arrangements. We plan to determine the structure experimentally. However, major advances in the accuracy of protein structure prediction were made recently by AlphaFold, an artificial intelligence system developed by DeepMind, which has revolutionized the field and has largely solved the protein folding problem. A similar AI system, RoseTTAFold, developed by David Baker’s lab at the University of Washington, has been publicly available. Here, we report our analysis of the structure of this protein, predicted using both of these algorithms and of a predicted structural model for the dimeric form of the enzyme using ClusPro. Our results strongly support a conserved catalytic mechanism requiring magnesium, which is common with all previously solved malate synthase isoforms. KEYWORDS: Glyoxylate Cycle; Malate synthase; Protein Prediction; Thermophile; Sulfolobus acidocaldarius; Magnesium; AlphaFold; RoseTTAFold
{"title":"The Predicted Structure of a Thermophilic Malate Synthase","authors":"Shaelee Nielsen, Jantzen Orton, Bruce Howard","doi":"10.33697/ajur.2024.103","DOIUrl":"https://doi.org/10.33697/ajur.2024.103","url":null,"abstract":"This project aims to solve the structure of the crenarchaeal Sulfolobus acidocaldarius enzyme malate synthase. Other known malate synthase enzymes have been found to require a magnesium ion in the active site to carry out catalytic activities, but a study reported that S. acidocaldarius malate synthase does not require magnesium. This suggests a novel mechanism for this enzyme. Additionally, the mature S. acidocaldarius protein is approximately 100 residues larger than any other structurally characterized malate synthase. It has also been reported to form a dimer, while previously solved structures have only displayed monomeric, trimeric, and hexameric arrangements. We plan to determine the structure experimentally. However, major advances in the accuracy of protein structure prediction were made recently by AlphaFold, an artificial intelligence system developed by DeepMind, which has revolutionized the field and has largely solved the protein folding problem. A similar AI system, RoseTTAFold, developed by David Baker’s lab at the University of Washington, has been publicly available. Here, we report our analysis of the structure of this protein, predicted using both of these algorithms and of a predicted structural model for the dimeric form of the enzyme using ClusPro. Our results strongly support a conserved catalytic mechanism requiring magnesium, which is common with all previously solved malate synthase isoforms. KEYWORDS: Glyoxylate Cycle; Malate synthase; Protein Prediction; Thermophile; Sulfolobus acidocaldarius; Magnesium; AlphaFold; RoseTTAFold","PeriodicalId":72177,"journal":{"name":"American journal of undergraduate research","volume":"31 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140360522","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Olivia Atkins, Samantha Lopez, Yizhe Ma, Louis Roberts
Human skin aging is characterized by epidermal and dermal thinning, loss of elasticity, and wrinkles. Keratinocytes, the most common type of skin cell and fibroblasts, present in the cellular stroma beneath the skin’s surface, each play a role in aging. Using these cell types in in vitro research can reveal a deeper understanding of the dermatological function and cellular changes in aged skin. 3D cell culture techniques provide an opportunity to use these cell types in a model that can more accurately mimic human skin. Treatment of aging skin is of interest to both medical and consumer communities. Retinoic acid (RA) is a metabolite of vitamin A and retinol that assists in cell proliferation, differentiation, and immune functions. Over the counter (OTC) and prescription retinoids are common topical products used for anti-aging and acne treatments. This study seeks to determine the impact of topical retinoid creams on keratinocyte proliferation and morphology in 3D cell culture models of aged and unaged human skin. NIH-3T3 fibroblasts were embedded in a 3D collagen matrix of varying thickness, and HaCaT keratinocytes were seeded on top of the matrix at varying seeding densities to mimic aging and youthful skin. 0.1 µM 0.025% tretinoin and 0.1 µM 0.1% adapalene topical creams were prepared in culture medium and used to treat cells daily, on alternate days, or just once during a week-long period. Alamar Blue assays and microscopy showed that tretinoin treatment was cytotoxic at this concentration, with a single treatment reducing cell viability by ~43% compared to the untreated control. Adapalene treatment, while showing significantly greater cell proliferation than tretinoin, did not exceed the proliferation of the untreated control. It is understood that retinol increases cell turnover by killing cells rapidly, so it is proposed that in our model, the rate of proliferation does not overcome the rate of cell death. Cell viability trends remain similar between young and old skin model treatments. Future studies should focus on creating a 3D model more accurately representing the aging in vivo skin environment where keratinocytes can be readily differentiated from epidermal stem cells. KEYWORDS: HaCaTs; NIH-3T3; Retinoids; Retinoic Acid; Tretinoin; Adapalene; 3D Collagen Gel; Proliferation
{"title":"Effect of Retinoic Acid on HaCaT and NIH-3T3 cells in an in vitro 3D Collagen Cell Culture Skin Model","authors":"Olivia Atkins, Samantha Lopez, Yizhe Ma, Louis Roberts","doi":"10.33697/ajur.023.093","DOIUrl":"https://doi.org/10.33697/ajur.023.093","url":null,"abstract":"Human skin aging is characterized by epidermal and dermal thinning, loss of elasticity, and wrinkles. Keratinocytes, the most common type of skin cell and fibroblasts, present in the cellular stroma beneath the skin’s surface, each play a role in aging. Using these cell types in in vitro research can reveal a deeper understanding of the dermatological function and cellular changes in aged skin. 3D cell culture techniques provide an opportunity to use these cell types in a model that can more accurately mimic human skin. Treatment of aging skin is of interest to both medical and consumer communities. Retinoic acid (RA) is a metabolite of vitamin A and retinol that assists in cell proliferation, differentiation, and immune functions. Over the counter (OTC) and prescription retinoids are common topical products used for anti-aging and acne treatments. This study seeks to determine the impact of topical retinoid creams on keratinocyte proliferation and morphology in 3D cell culture models of aged and unaged human skin. NIH-3T3 fibroblasts were embedded in a 3D collagen matrix of varying thickness, and HaCaT keratinocytes were seeded on top of the matrix at varying seeding densities to mimic aging and youthful skin. 0.1 µM 0.025% tretinoin and 0.1 µM 0.1% adapalene topical creams were prepared in culture medium and used to treat cells daily, on alternate days, or just once during a week-long period. Alamar Blue assays and microscopy showed that tretinoin treatment was cytotoxic at this concentration, with a single treatment reducing cell viability by ~43% compared to the untreated control. Adapalene treatment, while showing significantly greater cell proliferation than tretinoin, did not exceed the proliferation of the untreated control. It is understood that retinol increases cell turnover by killing cells rapidly, so it is proposed that in our model, the rate of proliferation does not overcome the rate of cell death. Cell viability trends remain similar between young and old skin model treatments. Future studies should focus on creating a 3D model more accurately representing the aging in vivo skin environment where keratinocytes can be readily differentiated from epidermal stem cells. KEYWORDS: HaCaTs; NIH-3T3; Retinoids; Retinoic Acid; Tretinoin; Adapalene; 3D Collagen Gel; Proliferation","PeriodicalId":72177,"journal":{"name":"American journal of undergraduate research","volume":"73 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139132334","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sidewalks are an important part of public space, but they are becoming increasingly dangerous, especially at night. Therefore, it is important that sidewalks are adequately illuminated to meet the safety, comfort, and accessibility needs (i.e., provide high levels of pedestrian reassurance) to sidewalk users. The objective of this case study was to quantitatively measure and subsequently explore the spatial and statistical distributions of light intensities along the sidewalks that surround Southern Utah University in Cedar City, Utah. A secondary objective was to develop a set of “adequate lighting” guidelines (i.e., 5 to 10 lux) to help identify areas that could benefit from sidewalks lighting enhancements. A digital light meter was used to measure horizontal light intensity, in lux, at a systematic sample of 208 points along the sidewalks within the study area. Geographic coordinates were also collected for each sample observation to enable mapping and spatial analysis of the light intensity data. Results indicate 61% of the observations have lux values equal to zero (complete darkness), 13.4% met or exceeded the minimum guidelines, while 4.3% fell within the “adequate lighting” guidelines adopted by this case study. These results suggest that sidewalks are too dark in too many places to provide reassurance to sidewalk users in the study area. The mapping and spatial analysis results from this case study also provide information to support targeted visibility enhancements of sidewalks within the study area. KEY WORDS: Lighting; Optimum Illuminance; Luminometer; Sidewalks; Pedestrians; Safety; Security; Reassurance
{"title":"Walking After Dark: A Sidewalk Illumination Case Study in Cedar City, UT","authors":"Sabrina Waite, Ian Nelson, Jamie Spinney","doi":"10.33697/ajur.2023.092","DOIUrl":"https://doi.org/10.33697/ajur.2023.092","url":null,"abstract":"Sidewalks are an important part of public space, but they are becoming increasingly dangerous, especially at night. Therefore, it is important that sidewalks are adequately illuminated to meet the safety, comfort, and accessibility needs (i.e., provide high levels of pedestrian reassurance) to sidewalk users. The objective of this case study was to quantitatively measure and subsequently explore the spatial and statistical distributions of light intensities along the sidewalks that surround Southern Utah University in Cedar City, Utah. A secondary objective was to develop a set of “adequate lighting” guidelines (i.e., 5 to 10 lux) to help identify areas that could benefit from sidewalks lighting enhancements. A digital light meter was used to measure horizontal light intensity, in lux, at a systematic sample of 208 points along the sidewalks within the study area. Geographic coordinates were also collected for each sample observation to enable mapping and spatial analysis of the light intensity data. Results indicate 61% of the observations have lux values equal to zero (complete darkness), 13.4% met or exceeded the minimum guidelines, while 4.3% fell within the “adequate lighting” guidelines adopted by this case study. These results suggest that sidewalks are too dark in too many places to provide reassurance to sidewalk users in the study area. The mapping and spatial analysis results from this case study also provide information to support targeted visibility enhancements of sidewalks within the study area. KEY WORDS: Lighting; Optimum Illuminance; Luminometer; Sidewalks; Pedestrians; Safety; Security; Reassurance","PeriodicalId":72177,"journal":{"name":"American journal of undergraduate research","volume":"93 9","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139131891","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Guaranteed admission programs are a type of college access program that provide students who meet certain criteria (e.g., a minimum GPA) with guaranteed admission to one or more colleges. This paper studies guaranteed admission agreements between California State University San Marcos (CSUSM) and its local school district to evaluate if smaller scale, local guaranteed admission programs have comparable impacts on college enrollment rates to previously studied state-wide programs. Employing a regression discontinuity (RD) design around the program’s GPA cutoff conditional on students satisfying other program requirements, this paper finds that the program significantly increased enrollment at CSUSM and at any California State University (CSU) and increased (not significantly) the likelihood of students enrolling at four-year institutions compared to two-year alternatives. In addition, the program disproportionally affected students from underrepresented backgrounds (e.g., first-generation, nonwhite, and low-income backgrounds), suggesting that local guaranteed admission programs also have the potential to increase representation at four-year public institutions and encourage underrepresented students to enroll at higher-quality postsecondary institutions. KEYWORDS: Guaranteed Admission; College Enrollment; College Admissions; College Access; Higher Education; California State University; Education Policy; Local Policy
{"title":"Increasing Access to a Four–Year College: Impacts of a California State University Guaranteed Admission Program on College Enrollment Rates","authors":"Joleen Chiu","doi":"10.33697/ajur.2023.094","DOIUrl":"https://doi.org/10.33697/ajur.2023.094","url":null,"abstract":"Guaranteed admission programs are a type of college access program that provide students who meet certain criteria (e.g., a minimum GPA) with guaranteed admission to one or more colleges. This paper studies guaranteed admission agreements between California State University San Marcos (CSUSM) and its local school district to evaluate if smaller scale, local guaranteed admission programs have comparable impacts on college enrollment rates to previously studied state-wide programs. Employing a regression discontinuity (RD) design around the program’s GPA cutoff conditional on students satisfying other program requirements, this paper finds that the program significantly increased enrollment at CSUSM and at any California State University (CSU) and increased (not significantly) the likelihood of students enrolling at four-year institutions compared to two-year alternatives. In addition, the program disproportionally affected students from underrepresented backgrounds (e.g., first-generation, nonwhite, and low-income backgrounds), suggesting that local guaranteed admission programs also have the potential to increase representation at four-year public institutions and encourage underrepresented students to enroll at higher-quality postsecondary institutions. KEYWORDS: Guaranteed Admission; College Enrollment; College Admissions; College Access; Higher Education; California State University; Education Policy; Local Policy","PeriodicalId":72177,"journal":{"name":"American journal of undergraduate research","volume":"124 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139134156","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：