American journal of undergraduate research最新文献_第8页

Synthesis of Graphene Oxide Enhanced Agar Composites: A Biocompatible Photo-catalyst for Degradation of Organic Dyes 氧化石墨烯增强琼脂复合材料的合成:降解有机染料的生物相容性光催化剂

American journal of undergraduate research Pub Date : 2020-12-30 DOI: 10.33697/ajur.2020.025

S. Dindorkar, Jaymin Mistry, J. Hire, Khushi Jain, Nandini Khona, Shreya Peddakolmi, Paresh More

{"title":"Synthesis of Graphene Oxide Enhanced Agar Composites: A Biocompatible Photo-catalyst for Degradation of Organic Dyes","authors":"S. Dindorkar, Jaymin Mistry, J. Hire, Khushi Jain, Nandini Khona, Shreya Peddakolmi, Paresh More","doi":"10.33697/ajur.2020.025","DOIUrl":"https://doi.org/10.33697/ajur.2020.025","url":null,"abstract":"Herein we report the synthesis of graphene oxide-based agar composites using a solution casting method. Graphene oxide was synthesized by modified Hummer’s method and was characterized using X-ray diffraction (XRD) and Raman spectroscopy. The graphene oxide-based agar composites were characterized using X-ray diffraction (XRD) and UV-visible spectroscopy. Optical band gap obtained from the Tauc plot showed that the composites could be used in the photodegradation of dyes. The synthesized composite material was checked for its practical applicability in the degradation of methylene blue dye under solar irradiation; with an increase in the concentration of graphene oxide, catalyst, and H2O2, the rate constant increases. The rate constant was found to be inversely proportional to the concentration of methylene blue dye. Dosage of graphene oxide was found to be the most prominent factor in increasing the rate of photodegradation. It is clear from the data for the reaction system that the degradation reaction follows pseudo-first-order kinetics.\u0000Keywords: Composites; Ultra-sonication; Photodegradation; Methylene Blue; XRD; Graphene Oxide; Kinetics; Biocompatibility","PeriodicalId":72177,"journal":{"name":"American journal of undergraduate research","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46681501","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}

引用次数: 0

Cyclophosphamide Depletes Ovarian Follicles in Mice During Both the Light and Dark Phases of the Circadian Cycle 环磷酰胺在昼夜节律周期的光明和黑暗阶段消耗小鼠卵巢卵泡

American journal of undergraduate research Pub Date : 2020-12-30 DOI: 10.33697/ajur.2020.023

B. Koch, Kristen A. Roosa

{"title":"Cyclophosphamide Depletes Ovarian Follicles in Mice During Both the Light and Dark Phases of the Circadian Cycle","authors":"B. Koch, Kristen A. Roosa","doi":"10.33697/ajur.2020.023","DOIUrl":"https://doi.org/10.33697/ajur.2020.023","url":null,"abstract":"The alkylating agent cyclophosphamide (CY) is a potent ovarian toxicant. It damages growing follicles and causes premature activation and depletion of the resting follicles that constitute the ovarian reserve. While there is abundant information on the impact of CY on the ovary and its toxicity mechanisms, the influence of the circadian rhythm on ovarian toxicity has not been evaluated. To test the hypothesis that time of exposure affects ovarian toxicity of CY, C57BL/6 mice were treated with a single injection of CY (75 mg/kg) at either two hours after lights on (Zeitgeber time (ZT) 02) or two hours after lights off (ZT14). Toxicity was evaluated one week after treatment by counting ovarian follicles in histological sections. Fewer primordial follicles were counted in the ovaries of CY-treated animals at both treatment times, and fewer antral follicles were counted in the ovaries of animals treated at ZT02. There was no difference in the number of primordial follicles in the ovaries of CY-treated animals between the two treatment times. These results demonstrate that CY-induced depletion of the ovarian reserve occurs when mice are exposed early in the light phase and early in the circadian cycle’s dark phase. There is no impact of the circadian rhythm on follicle depletion by CY at these time points.\u0000KEYWORDS: Cyclophosphamide; ovary; circadian; ovarian follicles; toxicity; mouse; chronotherapy; alkylating agent","PeriodicalId":72177,"journal":{"name":"American journal of undergraduate research","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49236335","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}

引用次数: 0

A Brief History and Overview of Existential-Phenomenological Psychology 存在-现象学心理学简史与概述

American journal of undergraduate research Pub Date : 2020-09-30 DOI: 10.33697/AJUR.2020.020

Christopher Zieske

引用次数: 1

Microfibers in Mytilus species(Mollusca, Bivalvia)from Southern California Harbors, Beaches, and Supermarkets 来自南加州港口、海滩和超市的Mytilus物种（软体动物、双壳动物）的微纤维

American journal of undergraduate research Pub Date : 2020-09-30 DOI: 10.33697/AJUR.2020.019

Chloe Mankin, Andrea L. Huvard

{"title":"Microfibers in Mytilus species(Mollusca, Bivalvia)from Southern California Harbors, Beaches, and Supermarkets","authors":"Chloe Mankin, Andrea L. Huvard","doi":"10.33697/AJUR.2020.019","DOIUrl":"https://doi.org/10.33697/AJUR.2020.019","url":null,"abstract":"Plastic microfibers are an emerging threat to terrestrial and aquatic habitats worldwide. They are equivalent in size to planktonic organisms, making them available to a range of invertebrates. Bivalve mollusks can ingest and accumulate plastics via digestion and adherence to soft tissue. We determined the frequency and characteristics of microfiber pollution from wild Mytilus californianus and farmed Mytilus edulis populations that were collected from southern California harbors, beaches, and supermarkets (n=4 per site). Mussel organic matter was dissected using 30% H2O2. After adding a saline solution to separate the fibers, the liquid was filtered by vacuum filtration. The remaining fibers were examined with a magnification of 1~8x. In this short-term survey, the abundance of microfibers by sample and by shell length showed a significant difference between the harbor and beach sites. However, there was not a significant difference between the wild and farmed mussels examined. This study revealed widespread microfiber pollution and uptake by mussels in these locations and reinforces how bivalves can be used as a bioindicator of microfiber pollution.\u0000KEYWORDS: Microplastic; Microfiber; Mytilus; Biomonitoring; Bivalvia; Seafood; Human Health","PeriodicalId":72177,"journal":{"name":"American journal of undergraduate research","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44931054","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}

引用次数: 5

An Assessment of Sleep Duration and Determinants of Health in a Cross-Sectional Sample of Gynecologic Cancer Survivors in Los Angeles County 洛杉矶县妇科癌症幸存者横截面样本中睡眠时间和健康决定因素的评估

American journal of undergraduate research Pub Date : 2020-09-30 DOI: 10.33697/AJUR.2020.017

Ma’at Hembrick, M. Conner, Heather P. Tarleton

{"title":"An Assessment of Sleep Duration and Determinants of Health in a Cross-Sectional Sample of Gynecologic Cancer Survivors in Los Angeles County","authors":"Ma’at Hembrick, M. Conner, Heather P. Tarleton","doi":"10.33697/AJUR.2020.017","DOIUrl":"https://doi.org/10.33697/AJUR.2020.017","url":null,"abstract":"Cancer survivors have an increased risk of treatment-related deficits in physical health and low health-related quality of life. In this cross-sectional study, a health questionnaire was mailed to women from the Los Angeles County Cancer Surveillance Program aged 45-70 and diagnosed with cervical, endometrial, or ovarian cancer in 2005-2014. Of the 5,941 surveys with valid postal addresses, 586 (10%) were completed and returned. The average age of respondents was 66 years old, and 36% identified as non-white. Non-white respondents were less likely to have a college degree (p<0.001), more likely to sleep for less than seven hours each night (p<0.001), experience bodily pain (p<0.001), and have a diagnosis of cervical cancer (p=0.002), when compared to white respondents. Health behaviors and determinants were examined across cervical, endometrial, and ovarian cancer cases. Cervical cancer survivors reported sleeping less than 7 hours per night, on average (p=0.015). Race was associated with sleep duration among endometrial (p=0.002) and ovarian (p=0.003) cancer survivors. Menopausal status was associated with the relationship between race and sleep duration (p<0.001). Depression was inversely related to sleep duration (p = 0.022) but was not associated with race, menopausal status, time since treatment, physical activity, or cancer type. Postmenopausal cervical cancer survivors reported a moderate concern about fall risk compared to their premenopausal counterparts (p=0.048). Physical activity levels increased as time since treatment increased (p=0.003) regardless of cancer type. Race, menopausal status, depression, and cancer type impacted the sleep duration.\u0000KEYWORDS: Health Disparities; Sleep Duration; Depression; Gynecologic Cancers; Survivorship Care","PeriodicalId":72177,"journal":{"name":"American journal of undergraduate research","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42825266","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}

引用次数: 0

Bacillus cereus & Bacillus pumilus Harvested from a Copper Roof Inhibit the Growth of Other Microorganisms 从铜屋顶收获的蜡样芽孢杆菌和细芽孢杆菌抑制其他微生物的生长

American journal of undergraduate research Pub Date : 2020-09-30 DOI: 10.33697/AJUR.2020.016

A. Stiller, A. Fink, D. Mitchell

{"title":"Bacillus cereus & Bacillus pumilus Harvested from a Copper Roof Inhibit the Growth of Other Microorganisms","authors":"A. Stiller, A. Fink, D. Mitchell","doi":"10.33697/AJUR.2020.016","DOIUrl":"https://doi.org/10.33697/AJUR.2020.016","url":null,"abstract":"Bacteria growing under the effects of unique selective pressures have distinct adaptations allowing them to survive. Copper surfaces present challenges for bacterial survival because ions dissolve from the surfaces and disrupt cell membranes, thus inhibiting bacterial growth. In this study, the copper roof of Simons Hall in Collegeville, Minnesota was sampled for bacterial species during November 2018. Bacteria were isolated and grown in culture, and zones of inhibition were identified surrounding three of the bacterial colonies. Polymerase chain reaction (PCR) was used to identify two of the bacteria samples as Bacillus cereus and a third sample as Bacillus pumilus. Bacilli are large, rod-shaped, gram-positive bacteria commonly found in diverse environments. They are endospore-forming aerobes or facultative anaerobes. Initial experiments indicated that all three Bacillus strains had the ability to inhibit the growth of three environmental microorganisms. Results from growth curve experiments depicted inhibitory effects on environmental microorganisms at all stages of the growth curve, which is contrary to the prediction that the inhibitory behavior would appear at one specific period of the growth curve. Additional experiments involved plating isolates of Bacillus cereus and Bacillus pumilus with laboratory samples of Pseudomonas aeruginosa, Streptococcus pneumoniae, and Listeria monocytogenes to further understand the effectiveness of B. cereus and B. pumilus at inhibiting the growth of other microorganisms. These findings support previous studies and suggest that Bacillus are capable of inhibiting or killing other organisms. Further research will be conducted to illuminate the inhibitory mechanisms and identify potential therapeutic possibilities.\u0000KEYWORDS: Bacteria; Copper; Resistance; Growth Curve; Inhibition; Bacillus; Bacteriocin; Antimicrobial Peptides","PeriodicalId":72177,"journal":{"name":"American journal of undergraduate research","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43284798","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}

引用次数: 0

An Unlikely Symbiosis: Science and Law 不太可能的共生：科学与法律

American journal of undergraduate research Pub Date : 2020-09-30 DOI: 10.33697/AJUR.2020.018

E. Miller

引用次数: 0

A Narrative Literature Review of the Psychological Hindrances Affecting Return to Sport After Injuries 影响受伤后重返运动的心理障碍的叙事文献综述

American journal of undergraduate research Pub Date : 2020-04-28 DOI: 10.33697/ajur.2021.045

Ashley Sweeney

{"title":"A Narrative Literature Review of the Psychological Hindrances Affecting Return to Sport After Injuries","authors":"Ashley Sweeney","doi":"10.33697/ajur.2021.045","DOIUrl":"https://doi.org/10.33697/ajur.2021.045","url":null,"abstract":"After different sports injuries, athletes may experience various psychological emotions in response to such injuries, which could lead an athlete to feel stressed. These emotions include anger, fear, frustration, anxiety, and depression which may lead to lack of confidence in returning to their sport and/or fear of sustaining a new injury. This narrative review aims to determine the possible psychological hindrances present when an athlete is planning on returning to sport after injury to an anterior cruciate ligament (ACL) or after sustaining a concussion. The synthesized information for this review has been collected from researching the databases PubMed, SportDiscus, PsycInfo, and Google Scholar using search terms including “return to sport”, “ACL injury”, “concussion”, and “psychology”. Journal articles needed to be in English and published in the years 2009-2019; books and unpublished abstracts were excluded. A total of 42 studies were included and analyzed using deductive coding to organize and synthesize relevant articles into themes. The review summarizes the shared common and the different psychological hindrances that may be found in athletes after an ACL injury or concussion. Shared psychological characteristics for returning to sport following either an ACL injury or concussion included fear, self-esteem, control, anxiety, stress, recovery, and social support. Discovering the common and unique psychological barriers which may affect the injured athletes from returning to sport can help educate athletes’ families, coaches, and healthcare professionals, as well as promote discussions for the future to help athletes feel more secure in their return to their respective sport. KEYWORDS: ACL Injuries; Concussions; Sport Injuries; Athletes; Narrative Literature Review; Psychological Hindrances; Psychological Characteristics; Return to Sport; Psychology","PeriodicalId":72177,"journal":{"name":"American journal of undergraduate research","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46323682","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}

引用次数: 0

After Hurricanes Irma and Matthew: Living Shorelines Stabilize Sediments 飓风“伊尔玛”和“马修”过后：活的海岸线稳定沉积物

American journal of undergraduate research Pub Date : 2019-09-30 DOI: 10.33697/ajur.2019.024

Taryn Chaya, J. Veenstra, M. Southwell

{"title":"After Hurricanes Irma and Matthew: Living Shorelines Stabilize Sediments","authors":"Taryn Chaya, J. Veenstra, M. Southwell","doi":"10.33697/ajur.2019.024","DOIUrl":"https://doi.org/10.33697/ajur.2019.024","url":null,"abstract":"Constructed intertidal oyster reefs, an example of a “living shoreline”, can protect against erosion and loss of habitat, but can they prevent erosion during high-energy storm events such as hurricanes? Oyster reefs were constructed in 2012 within the Guana Tolomato Matanzas National Estuarine Research Reserve in Northeast Florida to stabilize the shoreline sediment and prevent erosion of an archeological site. Sediment cores were collected behind constructed oyster reefs before and after hurricanes Matthew (2016) and Irma (2017) to study changes in sediment particle size due to these high-energy storms. Pre-hurricane data were collected in 2016 from three different constructed reefs, as well as three control sites where no reef was present. Pre-hurricane sediment profiles behind the constructed reefs consisted of finer sediments, ~36% silt and clay, in the surface ~10-12 cm, with decreasing silt and clay and increasing sand content as depth increased. This was different than the sediment from the control sites with ~4% silt and clay in all depths sampled. Like the sediment profiles before the high energy storms, the post-hurricane sediment data showed a clear layer of finer sediment ~10-12 cm over coarser sediment. Although they were high-energy storms, the storms did not appear to significantly affect the sediment behind the constructed oyster reefs. Sediment profiles remained consistent after these storms but may not remain undisturbed during the next storm without some intervention because the oyster reefs have been degrading.\u0000KEYWORDS: Oyster Restoration; Living Shorelines; Hurricanes; Coastal Erosion; Sedimentation; Salt Marsh","PeriodicalId":72177,"journal":{"name":"American journal of undergraduate research","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42100876","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}

引用次数: 4

The Effectiveness of Debt Relief: Assessing the Influence of the HIPC Initiative and MDRI on Tanzania’s Health Sector 债务减免的有效性：评估重债穷国倡议和多边减债倡议对坦桑尼亚卫生部门的影响

American journal of undergraduate research Pub Date : 2019-09-30 DOI: 10.33697/ajur.2019.021

Fernando Lopez Oggier

{"title":"The Effectiveness of Debt Relief: Assessing the Influence of the HIPC Initiative and MDRI on Tanzania’s Health Sector","authors":"Fernando Lopez Oggier","doi":"10.33697/ajur.2019.021","DOIUrl":"https://doi.org/10.33697/ajur.2019.021","url":null,"abstract":"Debt relief initiatives have been part of the international development sphere since the early 1990s. With the launch of the Heavily Indebted Poor Country (HIPC) Initiative in 1996 and the Multilateral Debt Relief Initiative (MDRI) in 2005 many countries have been able to successfully qualify for debt relief. Tanzania has been one of the primary beneficiaries of debt relief over the years. While empirical evidence demonstrates that the country’s economic growth has been positively impacted by debt relief initiatives, other aspects of human development need to be analyzed to ensure a comprehensive assessment of the HIPC Initiative and the MDRI. This study compiles Tanzania’s health data into a composite indicator to perform a graphical analysis to compare the trends between health outcomes and external debt. The graphical analysis is contextualized through a qualitative analysis of political, economic and health financing literature from the Bank of Tanzania, UNICEF and USAID. The results indicate that there health outcomes improved throughout the whole study’s time period particularly after the HIPC Initiative. The health financing literature also points to increased development expenditure during this period. Nonetheless, the effects of debt relief seem to diminish in the long-term due to fluctuations in external donors and logistical barriers to budget execution. Tanzania also continues to face socio-economic and geographic disparities in health outcomes and funding. Some of the literature also states that the country’s weak system of checks and balances and the lack of robust institutions could cause opportunistic policy preferences that might not necessarily improve Tanzania’s health outcomes. \u0000KEYWORDS: Child Mortality Rate; Debt Relief; External Debt; Heavily Indebted Poor Country Initiative; International Monetary Fund; Life Expectancy; Maternal Mortality Rate; Multilateral Debt Relief Initiative; Official Development Aid; Prevalence of Undernourishment","PeriodicalId":72177,"journal":{"name":"American journal of undergraduate research","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46136874","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}

引用次数: 0