Trials, Tribulations, and Trends in Tumor Modeling in Mice

Selection of mouse models of cancer is often based simply on availability of a mouse strain and a known compatible tumor. Frequently this results in use of tumor models long on history but short on homology and quality control. Other factors including genetics, sex, immunological status, method and site of tumor implantation, technical competence, biological activity of the tumor, protocol sequence and timing, and selection of endpoints interact to produce outcomes in tumor models. Common reliance on survival and tumor burden data in a single mouse model often skews expectations towards high remission and cure rates; a finding seldom duplicated in clinical trials. Inherent limitations of tumor models coupled with the advent of new therapeutic targets reinforce need for careful attention to design, conduct, and stringent selection of in vivo and ex vivo endpoints. Preclinical efficacy testing for anti-tumor therapies should progress through a series of models of increasing sophistication that includes incorporation of genetically engineered animals, and orthotopic and combination therapy models. Pharmacology and safety testing in tumor-bearing animals may also help to improve predictive value of these models for clinical efficacy. Trends in bioinformatics, genetic refinements, and specialized imaging techniques are helping to maintain mice as the most scientifically and economically powerful model of malignant neoplasms

Building Resilience in Military Families: Development and Evaluation of a Military Child Intervention.

Over two million children in the United States have been directly affected by the deployment of a family service member since 2001. The impact of deployment on these children may pose significant mental health risks and emotional disturbances, including depression, anxiety, and behavioral problems. However, many military children and family members do exhibit resilience and thrive throughout the deployment cycle. A modified Resiliency Model of Family Stress, Adjustment and Adaptation was used to inform further exploration of resilience and child adjustment in military children. This dissertation includes three papers, each addressing mental health and resilience in military children. First, a detailed quantitative analysis paper reviews the effect of maternal stress and mental health on child adjustment in the context of a military deployment. A longitudinal study was conducted with National Guard family members who experienced a deployment, with a focus on maternal perspectives of positive and negative child adjustment outcomes before and after a military deployment. Results indicated that maternal mental health and parenting stress significantly predicted adverse child adjustment during pre- and post-deployment. In the second paper, a review of the literature examined current evidence-based interventions to promote resilience in military families. This paper introduces the concept of resilience and reviews opportunities to incorporate strength-based skills into clinical interventions. Despite the need for interventions to address the unique needs of military children, limited programs are currently available. Recommendations for future interventions are presented. Finally, the third paper introduces a resiliency intervention for military children and discusses its pilot findings. A case series was performed to provide detailed descriptive information from intervention participants. Parent-report of child mental health revealed a reduction in total emotional and behavioral difficulties after participation in the intervention. Participants reported reduced depression, anxiety, household chaos, and parenting stress after program participation. Findings indicated adequate feasibility and acceptability from participants. In summary, these findings contribute to greater understanding of resilience and child adjustment outcomes in military children. Future work should focus on continued intervention development and evaluation to provide evidence-based programs for integration into nursing research and practice.PhDNursingUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/133435/1/krohna_1.pd

Magnetoresistance Induced by Rare Strong Scatterers in a High Mobility 2DEG

We observe a strong negative magnetoresistance at non-quantizing magnetic fields in a high-mobility two-dimensional electron gas (2DEG). This strong negative magnetoresistance consists of a narrow peak around zero magnetic field and a huge magnetoresistance at larger fields. The peak shows parabolic magnetic field dependence and is attributed to the interplay of smooth disorder and rare strong scatterers. We identify the rare strong scatterers as macroscopic defects in the material and determine their density from the peak curvature.Comment: 5 pages, 4 figure

Drift mobility of long-living excitons in coupled GaAs quantum wells

We observe high-mobility transport of indirect excitons in coupled GaAs quantum wells. A voltage-tunable in-plane potential gradient is defined for excitons by exploiting the quantum confined Stark effect in combination with a lithographically designed resistive top gate. Excitonic photoluminescence resolved in space, energy, and time provides insight into the in-plane drift dynamics. Across several hundreds of microns an excitonic mobility of >10^5 cm2/eVs is observed for temperatures below 10 K. With increasing temperature the excitonic mobility decreases due to exciton-phonon scattering.Comment: 3 pages, 3 figure

Spectral Types of Planetary Host Star Candidates: Two New Transiting Planets?

Recently, 46 low-luminosity object transits were reported from the Optical Gravitational Lensing Experiment. Our follow-up spectroscopy of the 16 most promising candidates provides a spectral classification of the primary. Together with the radius ratio from the transit measurements, we derived the radii of the low-luminosity companions. This allows to examine the possible sub-stellar nature of these objects. Fourteen of them can be clearly identified as low-mass stars. Two objects, OGLE-TR-03 and OGLE-TR-10 have companions with radii of 0.15 R_sun which is very similar to the radius of the transiting planet HD209458B. The planetary nature of these two objects should therefore be confirmed by dynamical mass determinations.Comment: 4 pages, 3 figures, accepted for publication by A&A Letter

Defining Disparities in Cochlear Implantation through the Social Determinants of Health

Hearing loss is a global public health problem with high prevalence and profound impacts on health. Cochlear implantation (CI) is a well-established evidence-based treatment for hearing loss; however, there are significant disparities in utilization, access, and clinical outcomes among different populations. While variations in CI outcomes are influenced by innate biological differences, a wide array of social, environmental, and economic factors significantly impact optimal outcomes. These differences in hearing health are rooted in inequities of health-related socioeconomic resources. To define disparities and advance equity in CI, there is a pressing need to understand and target these social factors that influence equitable outcomes, access, and utilization. These factors can be categorized according to the widely accepted framework of social determinants of health, which include the following domains: healthcare access/quality, education access/quality, social and community context, economic stability, and neighborhood and physical environment. This article defines these domains in the context of CI and examines the published research and the gaps in research of each of these domains. Further consideration is given to how these factors can influence equity in CI and how to incorporate this information in the evaluation and management of patients receiving cochlear implants

Emotion and Meaning-Making: Affordances in the Classroom

It is well known that emotion plays a significant role in the learning process. In this study, we describe affect/emotion incidents as part of students’ personal knowledge construction efforts in three sixth grade classrooms. These affect/emotion responses are identified by word choice, topic, punctuation, or description. The role of each classroom as it served as an affordance for affect/emotion knowledge construction efforts is also discussed. We posit that the role of dialog and activity choice, which traditionally lie within the hands of the teacher, serve as the primary affordances through which students are provided opportunity to use affect/emotion responses in their classroom learning

The near-synchronous polar V1432 Aql (RX J1940.1-1025): Accretion geometry and synchronization time scale

The magnetic Cataclysmic Variable (mCV) V1432 Aql (RX 1940.1-1025) belongs to the four-member subclass of near-synchronous polars with a slight non-synchronism (<2 %) between the spin period of the white dwarf and the binary period. In these systems the accretion geometry changes periodically with phase of the beat cycle. We present the application of a dipole accretion model for near-synchronous systems developed by Geckeler & Staubert (1997a) to extended optical and X-ray data. We detect a significant secular change of the white dwarf spin period in V1432 Aql of dP_spin/dt = -5.4 (+3.7/-3.2) 10-9 s/s from the optical data set alone. This corresponds to a synchronization time scale tau_sync = 199 (+441/-75) yr, comparable to the time scale of 170 yr for V1500 Cyg. The synchronization time scale in V1432 Aql is in excellent agreement with the theoretical prediction from the dominating magnetic torque in near-synchronous systems. We also present period analyses of optical CCD photometry and RXTE X-ray data, which argue against the existence of a 4000 s period and an interpretation of V1432 Aql as an intermediate polar. The dipole accretion model also allows to constrain the relevant parameters of the accretion geometry in this system: the optical data allow an estimate of the dimensionless parameter (R_t0'/R_wd)1/2 sin(beta) = 3.6 (+2.7/-1.1), with a lower limit for the threading radius of R_t0' > 10 R_wd (68% confidence).Comment: 12 pages, 10 figures, 6 tables accepted by A&