Christine S. Grant

A microfluidic device to study cancer metastasis under chronic and intermittent hypoxia.

Metastatic cancer cells must traverse a microenvironment ranging from extremely hypoxic, within the tumor, to highly oxygenated, within the hosts vasculature. Tumor hypoxia can be further characterized by regions of both chronic and intermittent hypoxia. We present the design and characterization of a microfluidic device that can simultaneously mimic the oxygenation conditions observed within the tumor and model the cell migration and intravasation processes. This device can generate spatial oxygen gradients of chronic hypoxia and produce dynamically changing hypoxic microenvironments in long-term culture of cancer cells.

Sugar Acetates as CO2-philes: Molecular Interactions and Structure Aspects from Absorption Measurement Using Quartz Crystal Microbalance

Sugar acetates, recognized as attractive CO(2)-philic compounds, have potential uses as pharmaceutical excipients, controlled release agents, and surfactants for microemulsion systems in CO(2)-based processes. This study focuses on the quantitative examination of absorption of high pressure CO(2) into these sugar derivatives using quartz crystal microbalance (QCM) as a detector. In addition to the absorption measurement, the QCM is initially found to be able to detect the CO(2)-induced deliquescence of sugar acetates, and the CO(2) pressure at which the deliquescence happens depends on several influencing factors such as the temperature and thickness of the film. The CO(2) absorption in alpha-D-glucose pentaacetate (Ac-alpha-GLU) is revealed to be of an order of magnitude larger in comparison with its anomer Ac-beta-GLU, whereas alpha-D-galactose pentaacetate (Ac-alpha-GAL) absorbs CO(2) less than Ac-alpha-GLU due to the steric-hindrance between the acetyl groups on the anomeric and C4 carbons, implying the significant importance of the molecular structure and configuration of sugar acetates on the absorption. The effects of molecular size and acetyl number of sugar acetates on the CO(2) absorption are evaluated and the results indicate that the conformation and packing of crystalline sugar acetate as well as the accessibility of the acetyls are also vital for the absorption of CO(2). It is additionally found that a CO(2)-induced change in the structure from a crystalline system to an amorphous system results in an order of magnitude increase in CO(2) absorption. Further investigation illustrates the interaction strength between sugar acetates and CO(2) by calculating the thermodynamic parameters such as Henrys law constant, enthalpy and entropy of dissolution from the determined CO(2) absorption. Experiments and calculations demonstrate that sugar acetates exhibit high CO(2) absorption, as at least comparable to ionic liquids. Since the ionic liquids have potential uses in the separation of acidic gases, it is evident from this study that sugar acetates could be used as possible materials for CO(2) separation.

WASTE MINIMIZATION IN BATCH VESSEL CLEANING

Although the cleaning of processing vessels has always been a significant source of waste, only recently have fundamental studies been undertaken to understand the cleaning process. The study described here began with a review of the literature on industrial cleaning practices. The literature was found to be mainly empirical. In order to provide a practical direction for research into the cleaning process, observations were made of a commercial batch processing facility. Based on these observations, short-term process improvements are suggested, and a new area for fundamental research is identified. @KEYWORDS Waste minimization Reflux cleaning Reactor Batch vessel.

Dynamic hydration of phospholipid films in aqueous environments

Abstract A dynamic study of the hydration of phospholipid films attached to solid substrates when exposed to liquid water at room temperature is presented. The phospholipids used were 1,2-dipalmitoyl-sn-glycero-3-phosphatidylethanolamine (DPPE), and a modification of DPPE with a fluorescent molecular probe: n-(5-fluoresceinthicarbamoyl)-1,2-dipalmitoyl-sn-glycero-3-phosphatidylethanolamine, triethylammonium salt (FITC-DPPE). Three different experimental techniques were used: rates of hydration were measured by depositing the phospholipid film on a quartz crystal microbalance (QCM), total internal reflection fluorescence (TIRF) studies were carried out with FITC-DPPE films deposited on the internal surface of a cylindrical quartz tube, and X-ray diffraction analysis was used to determine possible changes of the film’s crystalline structure during hydration. The DPPE films exhibited different successive hydration stages: within the first 2 h, the films uniformly hydrate towards a limiting water uptake (short-time behavior); however, at one point, hydration rates suddenly increase and the hydration process continues for longer periods of time, of the order of 24 h. No evidence of change in the film crystalline structure was found when dry and hydrated DPPE films were analyzed by wide-angle X-ray diffraction. The FITC-DPPE films showed a completely different hydration pattern: water uptake reached a maximum value at short times and then decreased continuously until an asymptotic value was reached. The TIRF results on FITC-DPPE films show that the evolution of fluorescence with time closely resembles the hydration results obtained in the QCM. This is attributed to the self quenching occurring in the phospholipid films.

The Emotionality of Women Professors of Color in Engineering: A Critical Race Theory and Critical Race Feminism Perspective

In this chapter we suggest that although the number of African American and Latina professors of engineering has increased in the last decade, engineering faculty and engineering student populations remain grossly overrepresented by White men. Because of this, African American and Latina women professors often experience unique difficulties that stem from their race, gender, and the intersection of their race and gender. The purpose of this chapter is to use a Critical Race Theory (CRT) and Critical Race Feminism (CRF) framework to explore the emotions associated with being underrepresented women professors of color in engineering. In doing so, the authors focus on CRT’s tenet of Whiteness as Property, particularly the elements of the right of use and enjoyment and the right to exclude. Also, we utilize intersectionality theory from CRF to examine the interaction of race and gender in the experiences of the participants (Crenshaw, 1989). Our analysis concentrates on the emotions involved in interacting with faculty and students. Finally, we discuss strategies for coping with race and gender-related stress in academia.

Hydration and removal of supported phospholipid films in aqueous surfactant solutions

Dynamic studies of the hydration and removal of phospholipid films attached to solid substrates were performed. The phospholipids used were 1,2-dipalmitoyl-sn-glycero-3-phosphatidylethanolamine (DPPE), and a modification of DPPE containing a fluorescent molecular probe: n-(5-fluoresceinthicarbamoyl)-1,2-dipalmitoyl-sn-glycero-3-phosphatidylethanolamine, triethylammonium salt (FITC-DPPE). The phospholipid films were exposed to water and aqueous solutions of the anionic surfactant sodium dodecyl sulfate (SDS). The film mass was determined as a function of time by means of a quartz crystal microbalance (QCM). The crystalline structure of the film during the hydration process was analyzed by means of wide-angle X-ray diffraction. At low surfactant concentrations (below 20% of the critical micelle concentration (CMC)), the presence of surfactant increased the hydration rate of the film, as well as its maximum water uptake. At surfactant concentrations as low as 50% of the CMC, competitive hydration and removal of the phospholipid film were observed. X-Ray diffraction measurements show that the crystal structure of the DPPE films did not change significantly upon exposure to water and surfactant solutions. In contrast, FITC-DPPE films exhibited changes in the long-range spacing of their crystalline structure upon hydration.

Social media for sustainable engineering communication

This paper provides an overview of current research on social media applications, including user demographics and how social media websites define themselves. The paper also describes user activities using social media and suggests known strengths and weaknesses of social media, and concludes by outlining several recommendations for developing strong online communities.

Chapter 5 – Mentoring

Publisher Summary This chapter highlights the importance of mentorship. Mentoring is a term used to describe the positive interactions that occur between an experienced and trusted advisor and a less experienced individual or group of individuals that facilitate the professional and sometimes personal development of the junior person. The very nature of science requires mentorship. Often there is a senior scientist who is responsible for the overall intellectual productivity of a group of individuals. There may also be a management team associated with the implementation and/or commercialization of an idea, process, or product. At every step, information is exchanged and the knowledge is transferred. It is critical for scientists at every stage of their careers—but particularly as they begin—to understand the dynamics associated with the process of doing science in their particular fields and contexts, as well as the associated political issues. Mentoring is not the unhealthy control or domination of one person by someone with greater experience and power. It is neither the manipulation of a subordinate for professional gain nor the abuse of a connection with a person in a prominent position. While the advantages for mentees are obvious, mentors enjoy different rewards, including the satisfaction of seeing a protege succeed, and the sense of accomplishment that derives from that.

Mentoring: Empowering Your Success

Mentoring for empowerment and success requires strategic planning and positioning. This chapter highlights the types of mentors, expectations in mentoring relationships, identification and management of mentoring interactions and transitioning to colleague status. Special emphasis on peer, career, and personal mentoring. While some mentoring can occur spontaneously, science, technology, engineering, and mathematics professionals should take an active role in their own success by initiating, cultivating, and maintaining effective, healthy mentoring relationships.

Effect of Additive Components on Thermal Stability of Fiber Finishes

In an effort to investigate the thermal degradation of fiber finishes on fiber manufacturing equipment, different additive components (i.e., lubricants, emulsifiers, antistatic agents and antioxidants) of textile fiber finishes were thermally stressed at high temperature (i.e., 220 °C). Oxidative-degradation behavior of common components of formulated finishes has been evaluated independently and in mixtures with other components (formulated finish). Using chemical and physical analyses, the changes in the molecular weights and products of degradation were investigated. Thermal degradation of formulated finishes prepared in this research was compared with two ready-to-use formulated finishes from industry. Results of this work provide valuable insights that improve the thermal stability of textile fiber finishes.