Meyerhoff Program Research Articles

The effect of glycation and cyclic loading on the material properties of isolated arterial elastin

Event Abstract Back to Event The effect of glycation and cyclic loading on the material properties of isolated arterial elastin Joseph B. Washington1 and L D Timmie Topoleski1 1 UMBC, Mechanical Engineering, United States Introduction: Elastin is a stable protein capable of enduring over a billion cycles under normal hemostatic conditions, and is an attractive material for tissue engineering applications[1][2]. Elastin stores strain energy, allowing arteries to expand and recover as blood is pumped from the heart. Glycation, where glucose molecules react with a protein or lipid, is associated with arterial aging and increased stiffness. During cyclic loading of materials, mechanical properties such as stiffness and maximum stress may change, thus altering the biomechanical integrity of a tissue engineering scaffold. This study examined the effects of glycation and extended cyclic loading on mechanical properties of isolated arterial elastin. Methods: Porcine aortas were obtained from a local abattoir. Adherent tissue was removed and “dog-bone” shaped samples were cut with a custom die. Isolated elastin specimens were prepared using the method of Lu et al[2]. Specimens were placed in 5M glucose solution for 0 (control), 1, 15, or 30 days. Samples were cyclically loaded in tension using a custom-built material testing system[3], under displacement control at 1 Hz to a maximum displacement of 3mm. All tests were performed in PBS solution at 37°C. Samples were loaded for 25k, 50k, or 100k cycles and then monotonically tested in tension to failure at a strain rate of 0.05mm/sec. Stress (σ = load/initial cross-sectional area) and stretch ratio (λ = current length/initial length) were calculated, and a linear model was used to determine the stiffness (M) and maximum stress (σmax) for each sample. Results: Two-way ANOVA failed to show a significant difference (p < 0.05) in σmax between treatment time or number of cycles (Fig. 1). Tukey’s pairwise test revealed a significant difference between 0 and 100k cycles. There was a gradual increase in M in each treatment time (Fig. 2). Two-way ANOVA showed significant differences between treatment times (p = 0.002), but not for number of cycles. Discussion: Glycation leads to the creation of advanced glycation endproducts (AGEs), which form irreversible covalent crosslinks with proteins. AGE crosslinks accumulate over several weeks[4], but the maximum glycation treatment time in this study was 30 days. There may not have been time to form enough crosslinks to cause a detectable change in mechanical behavior. Future research should include longer treatment times. Within each treatment group, the stiffness decreased with increasing number of cycles, possibly due to accumulated elastin fiber damage. Longer treatment times may have increased AGE-elastin crosslinking, which may have counteracted any damage accumulation in the elastin before 50k cycles. However, breakdown of the crosslinks between 50k and 100k cycles may explain why differences were detected at 100k cycles. Conclusions: For less than 100k cycles, glycation had an effect on the stiffness of isolated elastin, but not on the maximum stress. Extended cyclic loading may amplify the effects of subtle initial damage such that it can be detected though changes in material properties. UMBC Graduate Meyerhoff Program; GAANN Fellowship, US Department of Education

BOOK/MEDIA REVIEWS

Beyond Stock Stories and Folktales: African Americans' Paths to STEM Fields, edited by Henry T. Frierson and William F. Tate. Bingley, UK: Emerald Group, 2011, 332 pp. $134.95, hardcover.The research collected in Beyond Stock Stories and Folktales: African Americans ' Paths to STEM Fields seeks to add new rigor to investigations of why African American students earn science, technology, engineering, and mathematics (STEM) degrees, and work in STEM occupations at a considerably lower rate than White students. While these disparities and their long persistence are well known anecdotes, stock stories, and folktales seem to dominate explanations of the phenomenon, rather than provide evidence. The papers organized by Henry Frierson and William Tate do an excellent job filling this gap, improving our understanding of the multiple dimensions of STEM disparities. Moreover, the book's weaknesses offer an opportunity for future research to grow out of Frierson and Tate's volume.The book is divided into five parts. The first (chapters one through three) describes the undergraduate experience for African Americans more broadly. The second part, chapters four through six, focus on males and the third part, chapters seven through nine, on females. Part four, chapters ten through twelve, addresses methods of ameliorating STEM disparities although these strategies are also alluded to in earlier chapters. Finally, part five, chapters thirteen through fifteen, reviews the experience of African Americans in PhD programs and faculty positions. The structure of the book is an appealing feature of Beyond Stock Stories and Folktales, because it highlights the quite different experiences of African Americans by gender and career stage. For example, the analysis of African American females in STEM degree programs provided in chapter seven reveals that they are approximately twice as likely as African American men to earn STEM degrees, a difference that is strongest in the life sciences. However, chapter 8 demonstrates that the strong performance of African American females relative to males in degree attainment is not replicated in the gender composition of STEM faculty, where women are outnumbered by men, even at HBCUs. African American men and women thus experience disparities at different points along the STEM pipeline.Chapter one identifies STEM programs that are successful and unsuccessful at producing African American graduate students relative to what would be predicted on the basis of the school's characteristics, particularly the racial composition of its undergraduate population. A similar approach is used in chapter twelve although the analysis in this later chapter is limited to U.S. citizens and permanent residents. Assessing questions about STEM disparities to the data in this way is essential, and these chapters form important bookends for the volume, but it is necessary to note the limitations of these analyses as well. Outliers, both positive and negative, are always anticipated in any population. Chapter one and twelve's identification of programs that produce an unexpectedly high number of African Americans is therefore only a first step in understanding success in remedying STEM disparities. A crucial question is whether this success is random or the result of a specific practice, and whether that practice can be duplicated elsewhere or scaled up.Such questions are ably taken up in subsequent chapters. Perhaps the best example is the exceptional analysis of the University of Maryland, Baltimore County's Meyerhoff Scholar's Program (MSP) in chapter three, a program that is referenced by other contributors as well. The Meyerhoff program offers scholarships, advising, mentorship, peer support, internships, and research opportunities to African American-and after 1996, non-African American-STEM students. What is particularly appealing about the third chapter is that it offers a convincing counter-factual (those students who decline MSP offers, but continue to study STEM elsewhere) which can be used to help attribute the resounding success of Meyerhoff students to the Meyerhoff program itself. …

Meyerhoff Scholars Program: A Strengths‐Based, Institution‐Wide Approach to Increasing Diversity in Science, Technology, Engineering, and Mathematics

The Meyerhoff Scholars Program at the University of Maryland, Baltimore County is widely viewed as a national model of a program that enhances the number of underrepresented minority students who pursue science, technology, engineering, and mathematics PhDs. The current article provides an overview of the program and the institution-wide change process that led to its development, as well as a summary of key outcome and process evaluation research findings. African American Meyerhoff students are 5× more likely than comparison students to pursue a science, technology, engineering, and mathematics PhD. Program components viewed by the students as most beneficial include financial scholarship, being a part of the Meyerhoff Program community, the Summer Bridge program, study groups, and summer research. Qualitative findings from interviews and focus groups demonstrate the importance of the Meyerhoff Program in creating a sense of belonging and a shared identity, encouraging professional development, and emphasizing the importance of academic skills. Among Meyerhoff students, several precollege and college factors have emerged as predictors of successful entrance into a PhD program in the science, technology, engineering, and mathematics fields, including precollege research excitement, precollege intrinsic math/science motivation, number of summer research experiences during college, and college grade point average. Limitations of the research to date are noted, and directions for future research are proposed.

Following the Leaders

Several institutions have begun to imitate aspects of the Meyerhoff program at the University of Maryland, Baltimore County, and the Biology Scholars Program at the University of California, Berkeley ( see main text ). However, none has published comprehensive data on what has been accomplished.

Enhancing the Number of African Americans Who Pursue STEM PhDs: Meyerhoff Scholarship Program Outcomes, Processes, and Individual Predictors.

The current study examines the outcomes, processes, and individual predictors of pursuit of a STEM PhD among African-American students in the Meyerhoff Scholarship Program. Meyerhoff students were nearly five times more likely than comparison students to pursue a STEM PhD. Program components consistently rated as important were financial scholarship, being part of the Meyerhoff Program community, the Summer Bridge program, study groups, staff academic advising, and summer research opportunities. Furthermore, focus group findings revealed student internalization of key Meyerhoff Program values, including a commitment to excellence, accountability, group success, and giving back. In terms of individual predictors, multinomial logit regression analyses revealed that Meyerhoff students with higher levels of research excitement at college entry were more likely to pursue a STEM PhD.

Making a difference: the social ecology of social transformation.

A multidisciplinary and multilevel framework for social transformation is proposed, encompassing four foundational goals: capacity-building, group empowerment, relational community-building, and culture-challenge. Intervention approaches related to each goal are presented at the setting, geographic community, and societal levels. Four exemplars of social transformation work are then discussed: the Accelerated Schools Project, Meyerhoff Program, ManKind Project, and women's movement. These examples illustrate the synergistic relationship among the four transformational goals, within and across levels of analysis, which is at the heart of the social transformation process. The paper concludes with three challenges to guide our efforts as we enter the new century: (1) to move social transformation to the center of our consciousness as a field; (2) to articulate jointly with allied disciplines, organizations, and citizen groups an encompassing, multidisciplinary, and multilevel framework for social transformation; and (3) to do the above with heart, soul, and humility.

Attracting Minorities to Science

The article “Wanted: A better way to boost numbers of minority Ph.D.s” by Jeffrey Mervis (News of the Week, 28 Aug., p. [1268][1]) addresses a serious problem. Some programs have been successful in creating magnets of promise. One that Mervis mentions is the Leadership Alliance, with headquarters at Brown University. James Wyche, a microbial geneticist and Associate Provost, heads a consortium that links approximately 28 institutions, including major research universities and ethnic colleges. This project has, over the past 7 years, proved that a climate supportive of minority scientists can bind participating institutions and envelop students in an expanded network of encouragement and interaction. We at Harvard are participants in the Consortium. In the graduate programs (Ph.D.) of the Graduate School of Arts and Sciences located at the Harvard Medical School, we currently have 35 members of underrepresented groups enrolled. This number does not include students enrolled in the M.D/Ph.D. program. For the years 1992–1996 (those covered by Mervis), we graduated an average of five such students per year. At the high school level, the Macy High School Science Program, now called “Ventures in Education,” and the Meyerhoff program at the University of Maryland Baltimore County are both successful. Why not follow the suggestion of Joel Oppenheim and mount a conference to promote an exchange of views among those whose programs are working? ![Figure][2] Participants at a recent Leadership Alliance conference CREDIT: RICK KOZAK As a white male recipient of a 1998 National Science Foundation (NSF) graduate fellowship, I have several observations on the ending of minority graduate fellowships First, the political climate dictates that affirmative action will end, and we must find innovative new ways to recruit minority scientists. I believe that scientists are well positioned to do this: In a previous generation, scientists were leaders in opening university doors to foreigners. International cooperation was common in science even during the Cold War and remains strong today. American scientists are even leading our efforts to foster ties with Cuba by lobbying to ease restrictions on their first-rate scientific community ([1][3]). We diversified our profession internationally without affirmative action, and I believe that we can integrate our profession domestically in the same manner. Second, I applaud suggestions to reduce the importance of scores on the Graduate Record Examination in awarding fellowships. This is a matter of common sense rather than equity: A multiple-choice test cannot measure the traits necessary for research success nearly as well as transcripts, resumes, and recommendations. Making allowances for candidates from smaller schools with fewer resources for advanced courses and research would also be a good step. Finally, I think we should put the loss of minority fellowships in perspective: The decision to pursue a career in science begins at the undergraduate level, when NSF fellowships are not yet an issue for prospective scientists. Also, many talented white students who are not likely to receive NSF fellowships still apply for graduate study and work as teaching assistants; why should we assume that minorities will lack the same chutzpah? Finally, minority fellowships were never intended for marginal cases in need of encouragement to remain in science. They are instead for dynamic and talented minorities for whom no recruitment is necessary. These are the people we want in science, and the only way to increase their ranks is to cast our nets wider long before they reach graduate school. 1. [↵][4]1. J. Kumagai , Phys. Today 51, 56 (August 1998). [OpenUrl][5] [1]: /lookup/doi/10.1126/science.281.5381.1268 [2]: pending:yes [3]: #ref-1 [4]: #xref-ref-1-1 View reference 1 in text [5]: {openurl}?query=rft.jtitle%253DPhys.%2BToday%26rft.volume%253D51%26rft.spage%253D56%26rft.atitle%253DPHYS%2BTODAY%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx

Moving beyond Black Achiever Isolation

Those who seek to understand the experiences of Black students on White campuses in the United States have far more information available to them at the close of the twentieth century than could have ever been imagined at the beginning. Because of the tremendous social, political, economic, and educational changes in our society over the past thirty years there has been an expansion in the study of Blacks in all aspects of the American culture. Not surprisingly, education has played a central role in increasing our knowledge about the lives and experiences of Blacks. Research that has focused on Black students on predominately White campuses overwhelmingly reveals a story of academic difficulty (Fleming, 1984; Nettles, 1988; Mow & Nettles, 1990; Allen, 1992). Consequently much of the research on Black students has focused on those who have pronounced academic needs and who are perceived as academically less prepared than their White counterparts. The disproportionate focus on Black underachievement in the literature not only distorts the image of the community of Black collegians, it creates, perhaps unintentionally, a lower set of expectations for Black student achievement. The purpose of this study was to examine, through extensive interviews, the academic, social, and racial experiences of high-achieving Black students enrolled in the Meyerhoff Program, a merit-based scholarship program for students in math, science, and engineering. Interview questions (explained below) were focused around three broad areas: academic experiences in and outside of the classroom, social interactions and relationships with peers/faculty, and experiences in, and perceptions of, a race specific program. Established in 1989, the Meyerhoff program initially was developed to address the underrepresentation of Black males in the hard sciences. In 1990 the first class of Black females was admitted, and in 1996 the program was expanded to include other minority and White students. At the time of this writing, there were eight classes of Meyerhoffs enrolled in the program. High ability in this study was defined by conventional measures such as Scholastic Aptitude Test (SAT) scores and Grade Point Average (GPA). The cohort of Meyerhoffs interviewed had an average high-school GPA of 3.5 on a 4.0 scale, average SAT math score of 621, and the average SAT total score was 1198. The fall semester average GPA in the senior year was 3.0. This study is based on interviews with the class of 1990, the second class of Meyerhoffs and the first to admit female students. The 1990 class enrolled 15 students, of whom 14 persisted to the senior year, and 12 students (6 males and 6 females) participated in the 60-90 minute interviews. The Meyerhoff program provides an enormous level of support for the students. There are thirteen different components of the program, including full, or in some cases (for affiliate scholars) partial, scholarship support, study groups, tutoring, personal and academic advising, and connections with mentors in the field who can help with career issues and internship placement. For a description of the program and the services it provides, see Fries-Britt (1997) and Hrabowski, Maton, and Greif (1998). Factors Affecting the Academic Success of Gifted Blacks Much of what we know about gifted Black students in general comes from the work of scholars who study Black students in elementary, junior high, and high-school environments. The scant research on gifted collegians combined with the limited research on Black adolescents and high-school students provides some insight into the issues encountered by this population. Like other students, gifted Black students face social-emotional adjustment issues, such as self-concept and acceptance by peers (Rubenzer, 1976; Baldwin, 1991; Roeper, 1991). For gifted Blacks the issues of self-concept are different from those of other Blacks and gifted White students (Exum, 1979). …

Identifying and Supporting Gifted African American Men

AbstractThis chapter looks at issues of identifying gifted African American male college students, characteristics they exhibit, and factors affecting their retention. The Meyerhoff Program is profiled as an example of a successful program for such students.

Maryland Program For Black Students To Admit Other Races, Maintain Mission

Eight years ago, the Meyerhoff Scholars Program at the University of Maryland, Baltimore County (UMBC), opened a special door to talented black male high school students wanting to study science or engineering. A year later, the program accepted black women. This year, students of other races are being invited to apply. The decision is not surprising. In 1994, the U.S. Court of Appeals for the 4th Circuit disallowed an exclusively black scholarship program at the University of Maryland, College Park. Last year, in a trend-setting decision, the Board of Regents for the University of California system abolished admissions based on race. And just two weeks ago, the U.S. Court of Appeals for the 5th Circuit invalidated an affirmative action program at the University of Texas, Austin. Caught in the thick of the debate on affirmative action, universities and colleges nationwide are reexamining programs and admissions that target race. The Meyerhoff program was created in 1988 ...

Enhancing the Success of African‐American Students in the Sciences: Freshman Year Outcomes

The Meyerhoff Program is an intensive, multicomponent program focused on enhancing the success of talented African‐American students in science and engineering at a predominantly white, medium‐sized university. The program components, taken together, address the four primary factors emphasized in the research literature as limiting minority student performance and persistence in science: knowledge and skills, motivation and support, monitoring and advising, and academic and social integration. Outcome analyses indicated that the first three cohorts of Meyerhoff students (total N=69) achieved an overall GPA (mean=3.5) significantly greater than that of an African‐American historical comparison sample (mean=2.8) of comparably talented science students at the university. This difference was even greater for first year science GPA (means of 3.4 and 2.4, respectively), and in specific science and mathematics courses. Observational and questionnaire data indicated that the Meyerhoff program study groups, peerbased community, financial scholarships, summer bridge program and staff appear to be especially important contributors to student success. Implications of the findings for enhancing the success of African‐American and other underrepresented populations in science are discussed.