Quantification of fracture interaction using stress intensity factor variation maps

Accurate and flexible models of fracture interaction are sought after in the fields of mechanics and geology. Stress intensity factors (SIFs) quantify the energy concentrated at the fracture tips and are perturbed from their isolated values when two fractures are close to one another. Using a three-dimensional finite element fracture mechanics code to simulate static fractures in tension and compression, interaction effects are examined. SIF perturbations are characterized by introducing three interaction measures: the circumferential and maximum SIF perturbation provide the “magnitude” of the effect of interaction, and the amplification to shielding ratio quantifies the balance between increased and decreased SIFs along the tip. These measures are used to demonstrate the change in interaction with fracture separation and to find the separation at which interaction becomes negligible. Interaction maps are constructed by plotting the values of the interaction measures for a static fracture as a second fracture is moved around it. These maps are presented for several common fracture orientations in tension. They explore interaction by highlighting regions in which growth is more likely to occur and where fractures will grow into nonplanar geometries. Interaction maps can be applied to fracture networks with multiple discontinuities to analyze the effect of geometric variations on fracture interaction

Bedrock Geology of Western Story County, Iowa

In Story County the glacial drift rests directly upon both Pennsylvanian and Mississippian rocks. The Pennsylvanian, as now known from outcrops and well borings, is limited to the Cherokee group. The Mississippian rocks known to directly underlie the drift are assigned to the following formations, in descending order, the St. Louis, Warsaw, Keokuk, Gilmore City, and the Hampton. Although it is highly probably that the Burlington formation, stratigraphically between the Keokuk and the Gilmore City, also underlies the drift, no evidence of it has as yet been recognized. The St. Louis and the Warsaw are the only exposed Mississippian formations

Differentiating Plasmodium falciparum alleles by transforming Cartesian X,Y data to polar coordinates

<p>Abstract</p> <p>Background</p> <p>Diagnosis of infectious diseases now benefits from advancing technology to perform multiplex analysis of a growing number of variables. These advances enable simultaneous surveillance of markers characterizing species and strain complexity, mutations associated with drug susceptibility, and antigen-based polymorphisms in relation to evaluation of vaccine effectiveness. We have recently developed assays detecting single nucleotide polymorphisms (SNPs) in the <it>P. falciparum </it>genome that take advantage of post-PCR ligation detection reaction and fluorescent microsphere labeling strategies. Data from these assays produce a spectrum of outcomes showing that infections result from single to multiple strains. Traditional methods for distinguishing true positive signal from background can cause false positive diagnoses leading to incorrect interpretation of outcomes associated with disease treatment.</p> <p>Results</p> <p>Following analysis of <it>Plasmodium falciparum </it>dihydrofolate reductase SNPs associated with resistance to a commonly used antimalarial drug, Fansidar (Sulfadoxine/pyrimethamine), and presumably neutral SNPs for parasite strain differentiation, we first evaluated our data after setting a background signal based on the mean plus three standard deviations for known negative control samples. Our analysis of single allelic controls suggested that background for the absent allele increased as the concentration of the target allele increased. To address this problem, we introduced a simple change of variables from customary (<it>X,Y</it>) (Cartesian) coordinates to planar polar coordinates (<it>X </it>= <it>r</it>cos(<it>θ</it>), <it>Y </it>= <it>r</it>sin(<it>θ</it>)). Classification of multidimensional fluorescence signals based on histograms of angular and radial data distributions proved more effective than classification based on Cartesian thresholds. Comparison with known diallelic dilution controls suggests that histogram-based classification is effective for major:minor allele concentration ratios as high as 10:1.</p> <p>Conclusion</p> <p>We have observed that the diallelic SNP data resulting from analysis of <it>P. falciparum </it>mutations is more accurately diagnosed when a simple polar transform of the (<it>X,Y</it>) data into (<it>r,θ</it>) is used. The development of high through-put methods for genotyping <it>P. falciparum </it>SNPs and the refinement of analytical approaches for evaluating these molecular diagnostic results significantly advance the evaluation of parasite population diversity and antimalarial drug resistance.</p

Dislocation Emission around Nanoindentations on a (001) fcc Metal Surface Studied by STM and Atomistic Simulations

We present a combined study by Scanning Tunneling Microscopy and atomistic simulations of the emission of dissociated dislocation loops by nanoindentation on a (001) fcc surface. The latter consist of two stacking-fault ribbons bounded by Shockley partials and a stair-rod dislocation. These dissociated loops, which intersect the surface, are shown to originate from loops of interstitial character emitted along the directions and are usually located at hundreds of angstroms away from the indentation point. Simulations reproduce the nucleation and glide of these dislocation loops.Comment: 10 pages, 4 figure

Report from the TeraGrid Evaluation Study, Part 1: Project Findings

TeraGrid integrates multiple high-performance computing resources at distributed provider facilities. In 2006, the National Science Foundation (NSF) awarded a grant to the University of Michigan's School of Information (UM-SI) to conduct an external evaluation of TeraGrid. The primary goals of the evaluation were to provide specific information to TeraGrid managers that will increase the likelihood of TeraGrid success, and to give NSF and policy makers general data that will assist them in making strategic decisions about future directions for cyberinfrastructure. In order to accomplish these objectives, the UM-SI study assessed four aspects of the TeraGrid project: 1) progress in meeting user requirements; 2) impact of TeraGrid on research outcomes; 3) quality and content of TeraGrid education, outreach, and training activities; and 4) satisfaction among TeraGrid partners. We employed a mixed method approach that consisted of a user workshop; participant observation; document analysis; interviews with 86 individuals representing five different categories; a survey of a sample of 595 TeraGrid users; and two surveys to assess TeraGrid tutorials held in 2006 and 2007. Most of the data were collected from June 2006 through May 2007. Findings from the evaluation study are presented in two parts. In this first part, we report results from analyses of all data collected during the investigation. Detailed findings from the user survey are presented in Part 2 of the report.National Science Foundationhttps://deepblue.lib.umich.edu/bitstream/2027.42/61838/2/TeraGrid_Evaluation_Report_Project_Findings_August_2008.pdfDescription of TeraGrid_Evaluation_Report_Project_Findings_August_2008.pdf : Final repor

TeraGrid User Workshop Final Report

In 2006, the NSF awarded a one-year grant to the University of Michigan’s School of Information (UM-SI) to conduct an external evaluation of TeraGrid. This report describes the results of the first major evaluation activity. On June 12, 2006 the UM-SI evaluation team conducted a workshop to begin to examine the relationship between TeraGrid’s development priorities and the needs of its users. The invitation-only workshop was funded by TeraGrid and was held at the University Place Conference Center in Indianapolis, Indiana. The TeraGrid User Workshop Final Report summarizes the data collected and information gained during the workshop.National Science Foundationhttp://deepblue.lib.umich.edu/bitstream/2027.42/61841/1/TeraGrid2006_Tutortials_Survey_Report.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/61841/4/2006_TGUser_Workshop_Report.pd

Relationships Among Disease, Social Support, and Perceived Health: A Lifespan Approach

We examined the relationship between the cumulative presence of major disease (cancer, stroke, diabetes, heart disease, and hypertension), social support, and self‐reported general and emotional well‐being in a community representative sample of predominantly White and African American respondents (N = 1349). Across all ages, greater presence of disease predicted poorer reported general health, and predicted lower emotional well‐being for respondents 40 and above. In contrast, social support predicted better‐reported general and emotional well‐being. We predicted that different types of social support (blood relatives, children, friends, community members) would be relatively more important for health in different age groups based on a lifespan or life stage model. This hypothesis was supported; across all ages, social support was related to better reported general and emotional health, but sources of support differed by age. Broadly, those in younger age groups tended to list familial members as their strongest sources of support, whereas older group members listed their friends and community members. As a whole, social support mediated the effect of disease on reported well‐being, however, moderated mediation by type of support was not significant. The results are consistent with a lifespan approach to changing social ties throughout the life course.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/116357/1/ajcp9758.pd

Integrin-dependent control of translation: engagement of integrin alphaIIbbeta3 regulates synthesis of proteins in activated human platelets.

Integrins are widely expressed plasma membrane adhesion molecules that tether cells to matrix proteins and to one another in cell-cell interactions. Integrins also transmit outside-in signals that regulate functional responses of cells, and are known to influence gene expression by regulating transcription. In previous studies we found that platelets, which are naturally occurring anucleate cytoplasts, translate preformed mRNA transcripts when they are activated by outside-in signals. Using strategies that interrupt engagement of integrin alphaIIbbeta3 by fibrinogen and platelets deficient in this integrin, we found that alphaIIbbeta3 regulates the synthesis of B cell lymphoma 3 (Bcl-3) when platelet aggregation is induced by thrombin. We also found that synthesis of Bcl-3, which occurs via a specialized translation control pathway regulated by mammalian target of rapamycin (mTOR), is induced when platelets adhere to immobilized fibrinogen in the absence of thrombin and when integrin alphaIIbbeta3 is engaged by a conformation-altering antibody against integrin alphaIIbbeta3. Thus, outside-in signals delivered by integrin alphaIIbbeta3 are required for translation of Bcl-3 in thrombin-stimulated aggregated platelets and are sufficient to induce translation of this marker protein in the absence of thrombin. Engagement of integrin alpha2beta1 by collagen also triggered synthesis of Bcl-3. Thus, control of translation may be a general mechanism by which surface adhesion molecules regulate gene expression

Activated platelets mediate inflammatory signaling by regulated interleukin 1β synthesis

Platelets release preformed mediators and generate eicosanoids that regulate acute hemostasis and inflammation, but these anucleate cytoplasts are not thought to synthesize proteins or cytokines, or to influence inflammatory responses over time. Interrogation of an arrayed cDNA library demonstrated that quiescent platelets contain many messenger RNAs, one of which codes for interleukin 1β precursor (pro–IL-1β). Unexpectedly, the mRNA for IL-1β and many other transcripts are constitutively present in polysomes, providing a mechanism for rapid synthesis. Platelet activation induces rapid and sustained synthesis of pro–IL-1β protein, a response that is abolished by translational inhibitors. A portion of the IL-1β is shed in its mature form in membrane microvesicles, and induces adhesiveness of human endothelial cells for neutrophils. Signal-dependent synthesis of an active cytokine over several hours indicates that platelets may have previously unrecognized roles in inflammation and vascular injury. Inhibition of β3 integrin engagement markedly attenuated the synthesis of IL-1β, identifying a new link between the coagulation and inflammatory cascades, and suggesting that antithrombotic therapies may also have novel antiinflammatory effects

The TEAM Approach to Improving Oncology Outcomes by Incorporating Palliative Care in Practice

Palliative care (PC) concurrent with usual oncology care is now the standard of care that is recommended for any patient with advanced cancer to begin within 8 weeks of diagnosis on the basis of evidence-driven national clinical practice guidelines; however, there are not enough interdisciplinary palliative care teams to provide such care. How and what can an oncology office incorporate into usual care, borrowing the tools used in PC randomized clinical trials (RCTs), to improve care for patients and their caregivers? We reviewed the multiple RCTs for common practical elements and identified methods and techniques that oncologists can use to deliver some parts of concurrent interdisciplinary PC. We recommend the standardized assessment of patient-reported outcomes, including the evaluation of symptoms with such tools as the Edmonton or Memorial Symptom Assessment Scales, spirituality with the FICA Spiritual History Tool or similar questions, and psychosocial distress with the Distress Thermometer. All patients should be assessed for how they prefer to receive information, their current understanding of their situation, and if they have considered some advance care planning. Approximately 1 hour of additional time with the patient is required each month. If the oncologist does not have established ties with spiritual care and social work, he or she should establish these relationships for counseling as required. Caregivers should be asked about coping and support needs. Oncologists can adapt PC techniques to achieve results that are similar to those in the RCTs of PC plus usual care compared with usual care alone. This is comparable to using data from RCTs of trastuzamab or placebo, adopting what was used in the RCTs without modification or dilution