Development of fuel cell electrodes, Electrode improvement and life testing, tasks 1 and 3 Final report, 30 Jun. 1966 - 30 Apr. 1968

Volt-ampere characteristics improvement and life testing of electrodes for hydrogen oxygen fuel cell

Teaching Race, Racism, and Racial Justice: Pedagogical Principles and Classroom Strategies for Course Instructors

Teaching on topics of race and racism presents unique challenges to leaders in the university classroom setting. Despite an increasing number of instructors bringing a critical analysis of racial in/justice to their curriculum, many report challenges in teaching this content effectively. In this article, we address these challenges. We define common challenges in teaching racial content and articulate four principles for course planning around topics of race, racism, and racial justice. Then, drawing on a systematic review of scholarship examining issues of difference within a diverse range of disciplinary settings, we introduce a set of five pedagogical strategies, and supporting classroom practices, that will help instructors effectively manage everyday classroom interactions. This article contributes to the vast literature on teaching race and anti-racist education by synthesizing guiding pedagogical principles for course planning and classroom management that are applicable in a wide array of disciplinary contexts and providing concrete strategies that committed instructors, at varying levels of experience, can implement in their courses

Teaching Race and Racial Justice: Developing Students’ Cognitive and Affective Understanding

Effectively addressing both cognitive and affective dimensions of learning is one of the greatest obstacles to teaching race and racial justice in higher education. In this article, we first explore the need to integrate attention to cognitive and affective development, along with evidence-based strategies for doing so. We then provide a case study of an undergraduate sociology course on environmental justice in which the instructor intentionally adopted holistic pedagogical principles of teaching race. Analyzing student responses from a pre- and post- course survey, course assignments, and instructor observations of student participation, we find that both white students and students of color experienced significant growth in their cognitive and affective understanding of the complexities of race and work toward racial justice. However, results also show how challenging it can be to create the conditions for productive multiracial dialogues that produce extensive affective development, particularly interpersonal skills of racial reconciliation. Reflecting on the limitations of the case, we conclude that more holistic teaching approaches are necessary to develop both students’ cognitive and affective abilities to navigate race and work against racism, and we make suggestions for faculty development and administrative support

Viral outbreak in corals associated with an in situ bleaching event: atypical herpes-like viruses and a new megavirus infecting Symbiodinium

Previous studies of coral viruses have employed either microscopy or metagenomics, but few have attempted to comprehensively link the presence of a virus-like particle (VLP) to a genomic sequence. We conducted transmission electron microscopy imaging and virome analysis in tandem to characterize the most conspicuous viral types found within the dominant Pacific reef-building coral genus Acropora. Collections for this study inadvertently captured what we interpret as a natural outbreak of viral infection driven by aerial exposure of the reef flat coincident with heavy rainfall and concomitant mass bleaching. All experimental corals in this study had high titers of viral particles. Three of the dominant VLPs identified were observed in all tissue layers and budding out from the epidermis, including viruses that were ∼70, ∼120, and ∼150 nm in diameter; these VLPs all contained electron dense cores. These morphological traits are reminiscent of retroviruses, herpesviruses, and nucleocytoplasmic large DNA viruses (NCLDVs), respectively. Some 300–500 nm megavirus-like VLPs also were observed within and associated with dinoflagellate algal endosymbiont (Symbiodinium) cells. Abundant sequence similarities to a gammaretrovirus, herpesviruses, and members of the NCLDVs, based on a virome generated from five Acropora aspera colonies, corroborated these morphology-based identifications. Additionally sequence similarities to two diagnostic genes, a MutS and (based on re-annotation of sequences from another study) a DNA polymerase B gene, most closely resembled Pyramimonas orientalis virus, demonstrating the association of a cosmopolitan megavirus with Symbiodinium. We also identified several other virus-like particles in host tissues, along with sequences phylogenetically similar to circoviruses, phages, and filamentous viruses. This study suggests that viral outbreaks may be a common but previously undocumented component of natural bleaching events, particularly following repeated episodes of multiple environmental stressors

17O NMR study of q=0 spin excitations in a nearly ideal S=1/2 1D Heisenberg antiferromagnet, Sr2CuO3, up to 800 K

We used 17O NMR to probe the uniform (wavevector q=0) electron spin excitations up to 800 K in Sr2CuO3 and separate the q=0 from the q=\pm\pi/a staggered components. Our results support the logarithmic decrease of the uniform spin susceptibility below T ~ 0.015J, where J=2200 K. From measurement of the dynamical spin susceptibility for q=0 by the spin-lattice relaxation rate 1/T_{1}, we demonstrate that the q=0 mode of spin transport is ballistic at the T=0 limit, but has a diffusion-like contribution at finite temperatures even for T << J.Comment: Submitted to Phys. Rev. Lett. 4 pages, 4 figure

Macroalgae Decrease Growth and Alter Microbial Community Structure of the Reef-Building Coral, Porites astreoides

With the continued and unprecedented decline of coral reefs worldwide, evaluating the factors that contribute to coral demise is of critical importance. As coral cover declines, macroalgae are becoming more common on tropical reefs. Interactions between these macroalgae and corals may alter the coral microbiome, which is thought to play an important role in colony health and survival. Together, such changes in benthic macroalgae and in the coral microbiome may result in a feedback mechanism that contributes to additional coral cover loss. To determine if macroalgae alter the coral microbiome, we conducted a field-based experiment in which the coral Porites astreoides was placed in competition with five species of macroalgae. Macroalgal contact increased variance in the coral-associated microbial community, and two algal species significantly altered microbial community composition. All macroalgae caused the disappearance of a γ-proteobacterium previously hypothesized to be an important mutualist of P. astreoides. Macroalgal contact also triggered: 1) increases or 2) decreases in microbial taxa already present in corals, 3) establishment of new taxa to the coral microbiome, and 4) vectoring and growth of microbial taxa from the macroalgae to the coral. Furthermore, macroalgal competition decreased coral growth rates by an average of 36.8%. Overall, this study found that competition between corals and certain species of macroalgae leads to an altered coral microbiome, providing a potential mechanism by which macroalgae-coral interactions reduce coral health and lead to coral loss on impacted reefs

Distribution and metabolism of antibodies and macromolecules in tumor tissue

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 2008.Vita.Includes bibliographical references.Tumor targeting drugs that selectively treat cancerous tissue are promising agents for lowering the morbidity and mortality of cancer. Within this field, antibody treatments for cancer are currently being developed for both imaging and therapeutic applications. A major limitation with this class of drugs is the poor distribution and low uptake in tumor tissue. Poor distribution leaves some cells completely devoid of treatment, while others experience marginally toxic concentrations that could foster drug resistance. The low overall uptake in vascularized tumors constrains the therapeutic index and lowers signal to noise ratios for imaging applications. Since antibody therapies are currently used to treat both bulk tumors and residual disease, an understanding of the limitations in targeting prevascular metastases and vascularized tumors is required. In order to circumvent the current limitations with antibody therapies, the underlying causes must first be determined. In this thesis, the various steps in tumor localization of antibodies are analyzed in order to determine which steps are limiting uptake and distribution. Mathematical models are developed that indicate the distance antibodies and other binding macromolecules will penetrate into tumors and micrometastases. These models can also estimate the maximum uptake and time course of antibody concentration in tumors. The experimental distribution of a CEA binding antibody is measured in tumor spheroids and a mouse xenograft system to validate the model predictions. Using dimensional analysis of the fundamental transport rates that occur in tumors and micrometastases, two main groups determine the distance antibodies will penetrate in tumor tissue.(cont.) The clearance modulus indicates whether antibody persistence in the blood is sufficient to allow the drug to reach all cells in the micrometastasis or vascularized tumor. The Thiele modulus, defined for antibody transport in tumors, relates the internalization and catabolism of bound antibodies on cancer cells to the maximum distance the antibodies will reach in the tissue. These groups are related to the overall time course and maximum uptake in tumors, indicating when all cells will be targeted, and what factors determine this limit. These models can aid in experimental design, data interpretation, and strategies to improve uptake.by Greg M. Thurber.Ph.D

Multicolor Fluorescent Intravital Live Microscopy (FILM) for Surgical Tumor Resection in a Mouse Xenograft Model

Background: Complete surgical resection of neoplasia remains one of the most efficient tumor therapies. However, malignant cell clusters are often left behind during surgery due to the inability to visualize and differentiate them against host tissue. Here we establish the feasibility of multicolor fluorescent intravital live microscopy (FILM) where multiple cellular and/or unique tissue compartments are stained simultaneously and imaged in real time. Methodology/Principal Findings: Theoretical simulations of imaging probe localization were carried out for three agents with specificity for cancer cells, stromal host response, or vascular perfusion. This transport analysis gave insight into the probe pharmacokinetics and tissue distribution, facilitating the experimental design and allowing predictions to be made about the localization of the probes in other animal models and in the clinic. The imaging probes were administered systemically at optimal time points based on the simulations, and the multicolor FILM images obtained in vivo were then compared to conventional pathological sections. Our data show the feasibility of real time in vivo pathology at cellular resolution and molecular specificity with excellent agreement between intravital and traditional in vitro immunohistochemistry. Conclusions/Significance: Multicolor FILM is an accurate method for identifying malignant tissue and cells in vivo. The imaging probes distributed in a manner similar to predictions based on transport principles, and these models can be used to design future probes and experiments. FILM can provide critical real time feedback and should be a useful tool for mor

Multichannel Imaging to Quantify Four Classes of Pharmacokinetic Distribution in Tumors

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/108598/1/jps24086.pd

Electronic structure of the Sr0.4Ca13.6Cu24O41Sr_{0.4}Ca_{13.6}Cu_{24}O_{41} incommensurate compound

We extracted, from strongly-correlated ab-initio calculations, a complete model for the chain subsystem of the $Sr_{0.4}Ca_{13.6}Cu_{24}O_{41}$ incommensurate compound. A second neighbor $t-J+V$ model has been determined as a function of the fourth crystallographic parameter $\tau$, for both low and room temperature crystallographic structures. The analysis of the obtained model shows the crucial importance of the structural modulations on the electronic structure through the on-site energies and the magnetic interactions. The structural distortions are characterized by their long range effect on the cited parameters that hinder the reliability of analyses such as BVS. One of the most striking results is the existence of antiferromagnetic nearest-neighbor interactions for metal-ligand-metal angles of $90^\circ$. A detailed analysis of the electron localization and spin arrangement is presented as a function of the chain to ladder hole transfer and of the temperature. The obtained spin arrangement is in agreement with antiferromagnetic correlations in the chain direction at low temperature