The Forum: Spring 2002

Spring 2002 journal of the Honors Program at the University of North Dakota. The issue includes stories, poems, essays and art by undergraduate students.https://commons.und.edu/und-books/1048/thumbnail.jp

Influence of organic molecules on the aggregation of TiO2 nanoparticles in acidic conditions

Engineered nanoparticles released into the environment may interact with natural organic matter (NOM). Surface complexation affects the surface potential, which in turn may lead to aggregation of the particles. Aggregation of synthetic TiO2 (anatase) nanoparticles in aqueous suspension was investigated at pH 2.8 as a function of time in the presence of various organic molecules and Suwannee River fulvic acid (SRFA), using dynamic light scattering (DLS) and high-resolution transmission electron microscopy (TEM). Results showed that the average hydrodynamic diameter and ?-potential were dependent on both concentration and molecular structure of the organic molecule. Results were also compared with those of quantitative batch adsorption experiments. Further, a time study of the aggregation of TiO2 nanoparticles in the presence of 2,3-dihydroxybenzoic acid (2,3-DHBA) and SRFA, respectively, was performed in order to observe changes in ?-potential and particle size over a time period of 9 months. In the 2,3-DHBA-TiO2 system, ?-potentials decreased with time resulting in charge neutralization and/or inversion depending on ligand concentration. Aggregate sizes increased initially to the micrometer size range, followed by disaggregation after several months. No or very little interaction between SRFA and TiO2 occurred at the lowest concentrations tested. However, at the higher concentrations of SRFA, there was an increase in both aggregate size and the amount of SRFA adsorbed to the TiO2 surface. This was in correlation with the ?-potential that decreased with increased SRFA concentration, leading to destabilization of the system. These results stress the importance of performing studies over both short and long time periods to better understand and predict the long-term effects of nanoparticles in the environment

Coping with Homonegative Experiences Among Gay Men: Impacts on Mental Health, Psychological Well-being, and Identity Growth

While minority stress research increasingly show that high rates of homonegative experiences can contribute to negative mental health outcomes in gay men, less is known about the ways in which gay men cope with these experiences and their potential to experience positive outcomes such as well-being and identity growth. Understanding the strengths of gay men in coping with numerous, multi-faceted homonegative experiences is essential in creating an accurate understanding of gay men’s development and informing research, policy, and practice around gay men’s well-being and growth. This study seeks to describe the nature of gay men’s homonegative experiences, describe the coping skills and resources used to cope with these experiences, examine the positive psychological outcomes of well-being and identity growth, and investigate the relationship between homonegative experiences, coping, and strength-based growth and well-being. Participants for the online survey included 214 self-identified gay men recruited through list-servs, e-newsletters, organizational email lists, and referrals. Descriptive data indicate that gay men: 1) Experience many types of homonegative experiences, in many environments, and at the hands of many people in their lives; 2) utilize many different coping skills to respond to homonegative experiences, as well as accessing social support and community resources; and 3) experience elevated levels of mental health problems, but also experience well-being and identity growth. Path models indicate that self-blame, self-distraction, humor, community involvement, and social support are important coping factors in predicting the impacts of homonegative experiences on mental health, well-being, and identity growth. Limitations and implications for future research and practice are also discussed.</p

Continuing and Expanding the Multicultural Social Justice Leadership Conversation: An Introduction to the Special Issue of the Journal for Social Action in Counseling and Psychology on the 2010 Multicultural Social Justice Leadership Development Academy

This paper provides a historical background and review of the literature on intergroup dialogues, with a focus on community-engaged dialogues. The authors illustrate the format, purpose, and community factors involved in the Day of Dialogue (DOD), an intergroup community dialogue series. An expansion of Zúñiga and Nagda’s (2001) stages of intergroup dialogue is used to critically examine dialogue issues and provide a structure for culturally appropriate, community-engaged implementation. Lessons learned from three years of DOD implementation are provided, including the following themes: Balancing process and content, maintaining flexibility, defining roles, identifying biases, identifying/engaging key players, allowing voices to be heard, mindfulness toward environment/structure, and promoting movement towards action. Concrete suggestions to guide future practice around creating effective, culturally appropriate, and community-engaged dialogues, as well as effectively empowering communities and fostering social change, will be discussed

Thiol-based H2O2 signalling in microbial systems

Cysteine residues, and in particular their thiolate groups, react not only with reactive oxygen species but also with electrophiles and with reactive nitrogen species. Thus, cysteine oxidation has often been linked to the toxic effects of some of these reactive molecules. However, thiol-based switches are common in protein sensors of antioxidant cascades, in both prokaryotic and eukaryotic organisms. We will describe here three redox sensors, the transcription factors OxyR, Yap1 and Pap1, which respond by disulfide bond formation to hydrogen peroxide stress, focusing specially on the differences among the three peroxide-sensing mechanisms.This work was supported by the Spanish Ministry of Science and Innovation (BFU2009-06933 and BFU2012-32045), PLAN E and FEDER, by the Spanish Program Consolider-Ingenio 2010 Grant CSD 2007-0020, and by SGR2009-195 from Generalitat de Catalunya (Spain) to E.H. E. H. is recipient of an ICREA Academia Award (Generalitat de Catalunya)