3,736 research outputs found

    Quantifying Microplastics in Migratory Birds: Loyola University Chicago Campus

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    Each fall and spring seasons, close to 5-million migratory birds use the Mississippi flyway to fly over Chicago as they travel thousands of miles to nesting or wintering grounds. Traveling primarily at night, birds use rest stops throughout North and South America to forage and refuel for their travels. Unfortunately, many birds will perish during this travel due to light pollution coupled with large, glass-covered buildings such as those in Chicago. Loyola’s SOAR program has been collecting and documenting these fatalities for years. Microplastics pose possible health risks to foraging birds, and with the vast expanse of land and water that migratory birds cover, they are likely to accumulate microplastics in their gastrointestinal (GI) tracts as they forage. This study examined the GI tracts of eight (8) different migratory bird species to determine if different feeding niches accumulate more or less microplastics in their bodies. The study showed that microplastic fibers may be found in any of the species examined, but no statistically significant trends across species or their respective feeding niches were found

    An Exact Renormalization Group analysis of 3-d Well Developed turbulence

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    We take advantage of peculiar properties of three dimensional incompressible turbulence to introduce a nonstandard Exact Renormalization Group method. A Galilean invariance preserving regularizing procedure is utilized and a field truncation is adopted to test the method. Results are encouraging: the energy spectrum E(k) in the inertial range scales with exponent -1.666+/- 0.001 and the Kolmogorov constant C_K, computed for several (realistic) shapes of the stirring force correlator, agrees with experimental data.Comment: 12 pg, 2figures, LaTex, To be published on Physics Letters

    Burgers velocity fields and dynamical transport processes

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    We explore a connection of the forced Burgers equation with the Schr\"{o}dinger (diffusive) interpolating dynamics in the presence of deterministic external forces. This entails an exploration of the consistency conditions that allow to interpret dispersion of passive contaminants in the Burgers flow as a Markovian diffusion process. In general, the usage of a continuity equation tρ=(vρ)\partial_t\rho =-\nabla (\vec{v}\rho), where v=v(x,t)\vec{v}=\vec{v}(\vec{x},t) stands for the Burgers field and ρ\rho is the density of transported matter, is at variance with the explicit diffusion scenario. Under these circumstances, we give a complete characterisation of the diffusive matter transport that is governed by Burgers velocity fields. The result extends both to the approximate description of the transport driven by an incompressible fluid and to motions in an infinitely compressible medium.Comment: Latex fil

    Endograft-preserving therapy of a patient with Coxiella burnetii-infected abdominal aortic aneurysm: a case report

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    <p>Abstract</p> <p>Introduction</p> <p><it>Coxiella burnetii</it>, the causative agent of Q fever, may cause endocarditis and vascular infections that result in severe morbidity and mortality. We report a case of a <it>C. burnetii</it>-infected abdominal aorta and its management in a patient with a previous endovascular aortic aneurysm repair.</p> <p>Case presentation</p> <p>A 62-year-old Caucasian man was admitted to our hospital three months after endovascular aortic aneurysm repair with a bifurcated stent graft. He had increasing abdominal complaints and general malaise. A computed tomography scan of his abdomen revealed several para-aneurysmal abscesses. Surgery was performed via midline laparotomy. The entire abdominal wall of his aneurysmal sac, including the abscesses, was removed. The vascular endoprosthesis showed no macroscopic signs of infection. The decision was made to leave the endograft in place because of the severe cardiopulmonary comorbidities, thereby avoiding suprarenal clamping and explantation of this device with venous reconstruction. The proximal and distal parts of the endograft were secured to the aortic wall and common iliac artery walls, respectively, to avoid future migration. Polymerase chain reaction for <it>C. burnetii </it>was positive in all specimens of aortic tissue. Specific antibiotic therapy was initiated. Our patient was discharged in good clinical condition after six days.</p> <p>Conclusions</p> <p>In our patient, the infection was limited to the abdominal aneurysm wall, which was removed, leaving the endograft in place. Vascular surgeons should be familiar with this bailout procedure in high-risk patients.</p

    Sexual selection protects against extinction

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    Reproduction through sex carries substantial costs, mainly because only half of sexual adults produce offspring. It has been theorised that these costs could be countered if sex allows sexual selection to clear the universal fitness constraint of mutation load. Under sexual selection, competition between (usually) males, and mate choice by (usually) females create important intraspecific filters for reproductive success, so that only a subset of males gains paternity. If reproductive success under sexual selection is dependent on individual condition, which depends on mutation load, then sexually selected filtering through ‘genic capture’ could offset the costs of sex because it provides genetic benefits to populations. Here, we test this theory experimentally by comparing whether populations with histories of strong versus weak sexual selection purge mutation load and resist extinction differently. After evolving replicate populations of the flour beetle Tribolium castaneum for ~7 years under conditions that differed solely in the strengths of sexual selection, we revealed mutation load using inbreeding. Lineages from populations that had previously experienced strong sexual selection were resilient to extinction and maintained fitness under inbreeding, with some families continuing to survive after 20 generations of sib × sib mating. By contrast, lineages derived from populations that experienced weak or non-existent sexual selection showed rapid fitness declines under inbreeding, and all were extinct after generation 10. Multiple mutations across the genome with individually small effects can be difficult to clear, yet sum to a significant fitness load; our findings reveal that sexual selection reduces this load, improving population viability in the face of genetic stress

    Oxidative stress and immunologic responses following a dietary exposure to PAHs in Mya arenaria

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    <p>Abstract</p> <p>Background</p> <p>The aim of this research was to investigate oxidative stress and immune responses following a dietary polycyclic aromatic hydrocarbon (PAH) exposure in a marine bioindicator organism, the soft shell clam, <it>Mya arenaria</it>. Immune parameters in hemolymph (haemocyte number, efficiency of phagocytosis and haemocyte activity) and assessment of oxidative stress using catalase (CAT) activity and levels of malondialdehyde (MDA) performed on the digestive gland were estimated as biomarkers in clams fed in mesocosm with PAH contaminated phytoplankton. MDA levels and CAT activities were also measured <it>in situ </it>in organisms sampled in a control site (Metis Beach, Québec, Canada) as well as organisms sampled in a site receiving domestic effluents (Pointe-au-Père, Québec, Canada), to assess effects of abiotic variables related to seasonal variations and mixed contamination on the selected parameters.</p> <p>Results</p> <p>Results on immune parameters suggest that the PAHs may interfere with the maturation and/or differentiation processes of haemocytes. MDA results showed that lipid peroxidation did not occur following the exposure. The levels of CAT activity corresponded to weak antioxidant activity (no significant differences). Recovery was noted for all the immune endpoints at the end of the experiment.</p> <p>Conclusion</p> <p>Results suggest that immune parameters are early biomarkers that can efficiently detect a physiological change during a short term exposure to low concentrations of PAHs. The <it>in situ </it>survey (in the natural environment) suggested that clams from the Pointe-au-Père site did not show any oxidative stress as well as the clams contaminated in mesocosm, probably due to the low concentrations of PAHs used for this study. MDA levels increased however in organisms from Metis Beach, a response probably related to domestic effluents or parasitism.</p

    Prognostic Breast Cancer Signature Identified from 3D Culture Model Accurately Predicts Clinical Outcome across Independent Datasets

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    One of the major tenets in breast cancer research is that early detection is vital for patient survival by increasing treatment options. To that end, we have previously used a novel unsupervised approach to identify a set of genes whose expression predicts prognosis of breast cancer patients. The predictive genes were selected in a well-defined three dimensional (3D) cell culture model of non-malignant human mammary epithelial cell morphogenesis as down-regulated during breast epithelial cell acinar formation and cell cycle arrest. Here we examine the ability of this gene signature (3D-signature) to predict prognosis in three independent breast cancer microarray datasets having 295, 286, and 118 samples, respectively. Our results show that the 3D-signature accurately predicts prognosis in three unrelated patient datasets. At 10 years, the probability of positive outcome was 52, 51, and 47 percent in the group with a poor-prognosis signature and 91, 75, and 71 percent in the group with a good-prognosis signature for the three datasets, respectively (Kaplan-Meier survival analysis, p&lt;0.05). Hazard ratios for poor outcome were 5.5 (95% CI 3.0 to 12.2, p&lt;0.0001), 2.4 (95% CI 1.6 to 3.6, p&lt;0.0001) and 1.9 (95% CI 1.1 to 3.2, p = 0.016) and remained significant for the two larger datasets when corrected for estrogen receptor (ER) status. Hence the 3D-signature accurately predicts breast cancer outcome in both ER-positive and ER-negative tumors, though individual genes differed in their prognostic ability in the two subtypes. Genes that were prognostic in ER+ patients are AURKA, CEP55, RRM2, EPHA2, FGFBP1, and VRK1, while genes prognostic in ER patients include ACTB, FOXM1 and SERPINE2 (Kaplan-Meier p&lt;0.05). Multivariable Cox regression analysis in the largest dataset showed that the 3D-signature was a strong independent factor in predicting breast cancer outcome. The 3D-signature accurately predicts breast cancer outcome across multiple datasets and holds prognostic value for both ER-positive and ER-negative breast cancer. The signature was selected using a novel biological approach and hence holds promise to represent the key biological processes of breast cancer

    Characterising B cell numbers and memory B cells in HIV infected and uninfected Malawian adults

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    BACKGROUND: Untreated human immunodeficiency virus (HIV) disease disrupts B cell populations causing reduced memory and reduced naïve resting B cells leading to increases in specific co-infections and impaired responses to vaccines. To what extent antiretroviral treatment reverses these changes in an African population is uncertain. METHODS: A cross-sectional study was performed. We recruited HIV-uninfected and HIV-infected Malawian adults both on and off antiretroviral therapy attending the Queen Elizabeth Central hospital in Malawi. Using flow cytometry, we enumerated B cells and characterized memory B cells and compared these measurements by the different recruitment groups. RESULTS: Overall 64 participants were recruited - 20 HIV uninfected (HIV-), 30 HIV infected ART naïve (HIV+N) and 14 HIV-infected ART treated (HIV+T). ART treatment had been taken for a median of 33 months (Range 12-60 months). Compared to HIV- the HIV+N adults had low absolute number of naïve resting B cells (111 vs. 180 cells/μl p = 0.008); reduced memory B cells (27 vs. 51 cells/μl p = 0.0008). The HIV+T adults had B-cell numbers similar to HIV- except for memory B cells that remained significantly lower (30 vs. 51 cells/μl p = 0.02). In the HIV+N group we did not find an association between CD4 count and B cell numbers. CONCLUSIONS: HIV infected Malawian adults have abnormal B-cell numbers. Individuals treated with ART show a return to normal in B-cell numbers but a persistent deficit in the memory subset is noted. This has important implications for long term susceptibility to co-infections and should be evaluated further in a larger cohort study

    High maternal mortality estimated by the sisterhood method in a rural area of Mali

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    <p>Abstract</p> <p>Background</p> <p>Maternal mortality is high in Mali. Nevertheless, there are few studies on this topic from rural areas, and current estimates are mostly based on studies from urban settings. Our objective was to estimate the maternal mortality ratio in Kita, rural Mali.</p> <p>Methods</p> <p>Using the "sisterhood method", we interviewed participants aged 15-50 years from 20 villages in Kita, Mali, and thereby created a retrospective cohort of their sisters in reproductive age. Based on population and fertility estimates, we calculated the lifetime risk of maternal death, and from that the estimated approximate maternal mortality ratio.</p> <p>Results</p> <p>The 2,039 respondents reported 4,628 sisters who had reached reproductive age. Of these 4,628 sisters, almost a third (1,233; 27%) had died, and 429 (9%) had died during pregnancy or childbirth. This corresponded to a lifetime risk of maternal death of 20% and a maternal mortality ratio of 3,131 per 100,000 live births (95% confidence interval 2,967-3,296), with a time reference around 1999.</p> <p>Conclusions</p> <p>We found a very high maternal mortality in rural Mali and this highlights the urgent need for obstetric services in the remote rural areas.</p
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