Computational Modeling of Lauric Acid at the Organic−Water Interface

Where water meets an immiscible liquid, the orientation and hydrogen bonding patterns of the molecules nearest the interface differ significantly from those in the bulk. These differences drive important interface-specific phenomena, including interfacial tension and the adsorption of other molecular species. Additionally, surfactants and other amphiphilic molecules present at the interface interact with both the aqueous and hydrophobic layers in a complex fashion that can dramatically change the characteristics of the interface as a whole. In this study, classical molecular dynamics computer simulations have been employed to investigate the accommodation of lauric acid at the water− hexane and water−carbon tetrachloride interfaces. Our results show that the behavior of surfactant molecules in the interfacial region is strongly influenced by the protonation of their headgroups. Deprotonated lauric acid molecules cause a larger increase in interfacial width than their protonated counterparts. The carboxylate headgroups of laurate anions in the interfacial region consistently point toward the water layer, while the orientation of the protonated lauric acid headgroups changes with depth into the water layer

Equity for women and underrepresented minorities in STEM: Graduate experiences and career plans in chemistry

7 pagesRecent events prompted scientists in the United States and throughout the world to consider how systematic racism affects the scientific enterprise. This paper provides evidence of inequities related to race–ethnicity and gender in graduate school experiences and career plans of PhD students in the top 100 ranked departments in one science, technology, engineering, and math (STEM) discipline, chemistry. Mixed-model regression analyses were used to examine factors that might moderate these differences. The results show that graduate students who identified as a member of a racial/ethnic group traditionally underrepresented in chemistry (underrepresented minorities, URM) were significantly less likely than other students to report that their financial support was sufficient to meet their needs. They were also less likely to report having supportive relationships with peers and postdocs. Women, and especially URM women, were significantly less likely to report supportive relationships with advisors. Despite their more negative experiences in graduate school, students who identified as URM expressed greater commitment to finishing their degree and staying in the field. When there was at least one faculty member within their departments who also identified as URM they were also more likely than other students to aspire to a university professorship with an emphasis on research. Men were significantly more likely than women to express strong commitment to finishing the PhD and remaining in chemistry, but this difference was stronger in top-ranked departments. Men were also more likely than women to aspire to a professorship with an emphasis on research, and this difference remained when individual and departmental-level variables were controlled

Changing the Chairs: Impact of Workshop Activities in Assisting Chemistry Department Chairs in Achieving Racial and Ethnic Diversity

5 pagesTo address the low levels of underrepresented minority (URM) faculty in top-ranked chemistry departments, the National Science Foundation, the U.S. Department of Energy, and the National Institutes of Health jointly sponsored a workshop for academic chemistry leaders in September 2007. The goal of the two-and-a-half-day workshop was to create an informed and committed community of chemistry leaders who will develop and promote programs and strategies to advance racial and ethnic equity in both the faculty and student body with the goal of increasing the number of U.S. citizens who are URM scientists. This paper reports the impact of this workshop on the attitudes of the department chair faculty members who attended the workshop. On the basis of surveys of the department chair faculty perceptions before and after the workshop, the results indicate that participants in the carefully planned intervention workshop changed their attitudes regarding reasons underlying the underrepresentation and barriers that minority faculty face in the field. These department chair faculty members also increasingly viewed the solution to diversifying chemistry departments as one in which they, their departments, and universities could play a role

The Chemistry Graduate Student Experience: Findings from an ACS Survey

8 pagesGraduate training is a key element in producing a scientific workforce that reflects the nation’s diversity. This paper examines data from a 2013 American Chemical Society (ACS) survey of 2,544 chemistry masters and doctoral students and reveals barriers to reaching this goal. Multivariate statistical analyses indicate that women reported significantly less supportive relationships with advisors. Women were less likely to plan to finish their degrees, and for PhD students, the discrepancy was larger for students at the start of their graduate program. Women were also less likely to pursue the next level of training, and the gender difference related to postdoctoral plans was greater for those who identified with a racial−ethnic group traditionally underrepresented in chemistry (underrepresented minority, URM). URM students who were beyond the first year of their graduate program reported significantly less supportive relationships with peers. They were also less likely to have funding sufficient to meet their needs and more often used personal resources including loans. Despite these difficulties, URM students were more likely to definitely plan to finish their degrees, and men who identified as URM were more likely to plan to pursue postdoctoral work. Independent of gender and identification as URMs, students in more highly ranked schools reported less advisor support. Extensive open-ended comments indicated that large proportions of the students desired more attention and meaningful feedback from advisors and changes within their programs to promote support for students and advisor accountability. Suggestions for future research are given, and a companion commentary discusses needed directions for change

Policies and Practices to Improve the Chemistry Graduate Student Experience: Implications of the ACS Survey of Graduate Students

4 pagesSTEM graduate education is vitally important in producing the talent needed to fuel our economy and provide solutions for the challenges we face in emerging diseases and climate change. Yet recent research indicates that women and students who identify as members of minority groups traditionally underrepresented in STEM face extraordinary challenges in their graduate careers. This commentary describes ways in which chemistry graduate education could become more supportive and inclusive through changes by graduate students, faculty, departments, funding agencies, and professional organizations. As a result the scientific workforce could utilize the full range of available talent and become more productive

Genome-Wide Transcriptional Response of Silurana (Xenopus) tropicalis to Infection with the Deadly Chytrid Fungus

Emerging infectious diseases are of great concern for both wildlife and humans. Several highly virulent fungal pathogens have recently been discovered in natural populations, highlighting the need for a better understanding of fungal-vertebrate host-pathogen interactions. Because most fungal pathogens are not fatal in the absence of other predisposing conditions, host-pathogen dynamics for deadly fungal pathogens are of particular interest. The chytrid fungus Batrachochytrium dendrobatidis (hereafter Bd) infects hundreds of species of frogs in the wild. It is found worldwide and is a significant contributor to the current global amphibian decline. However, the mechanism by which Bd causes death in amphibians, and the response of the host to Bd infection, remain largely unknown. Here we use whole-genome microarrays to monitor the transcriptional responses to Bd infection in the model frog species, Silurana (Xenopus) tropicalis, which is susceptible to chytridiomycosis. To elucidate the immune response to Bd and evaluate the physiological effects of chytridiomycosis, we measured gene expression changes in several tissues (liver, skin, spleen) following exposure to Bd. We detected a strong transcriptional response for genes involved in physiological processes that can help explain some clinical symptoms of chytridiomycosis at the organismal level. However, we detected surprisingly little evidence of an immune response to Bd exposure, suggesting that this susceptible species may not be mounting efficient innate and adaptive immune responses against Bd. The weak immune response may be partially explained by the thermal conditions of the experiment, which were optimal for Bd growth. However, many immune genes exhibited decreased expression in Bd-exposed frogs compared to control frogs, suggesting a more complex effect of Bd on the immune system than simple temperature-mediated immune suppression. This study generates important baseline data for ongoing efforts to understand differences in response to Bd between susceptible and resistant frog species and the effects of chytridiomycosis in natural populations

Модель професійної культури юриста: критерії та підходи

В статті визначається модель професійної культури

SECOND HARMONIC GENERATION AS A PROBE OF SURFACE STRUCTURE AND INTERFACIAL DYNAMICS AT THE SOLID/LIQUID INTERFACE

$^{1}$ For a recent review, see G.L. Richmond, J.M. Robinson and V.L. Shannon, Prog. in Surf. Sci. 28, 1 (1988).Author Institution: Chemical Physics Institute, University of OregonOver the past decade there has been a rapid growth in the studies using optical second harmonic generation (SHG) to probe surface properties of metals and $semiconductors.^{1}$ One of the major advantages of the technique is the ability to characterize surfaces in contact with other dense media. Our focus has been on metals and semiconductors in contact with liquids in an attempt to probe structural aspects of the surface and adjacent double layer. The studies to be described in this talk are ones which examine the rotational anisotropy in the SH response from single crystal electrode surfaces as the surface is rotated azimuthally. For the spectroscopist, studying the anisotropy in the SH response from these crystalline surfaces can provide important insight into the tensor elements which play a role in the overall SH response. Wavelength dependent studies have the potential of providing information about the electronic structure of the surface and possible surface states at the liquid/solid interface. From a more applications oriented viewpoint, the technique has the potential to provide insight into the morphological aspects of the crystalline surface and deposited overlayers. When performed in a time-resolved mode, the kinetics of deposition, surface atom reorganization and related electron transfer effects can be examined. The presentation will be an overview of these topics into which our most recent results with various single crystal surfaces in solution will be incorporated