178 research outputs found

    Contract Renegotiation and Rent Re-distribution: Who Gets Raked Over the Coals?

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    Policy shocks affect the rent distribution in long-term contracts, which can lead to such contracts being renegotiated. We seek an understanding of what aspects of contract design, in the face of a substantial policy shock, affect the propensity to renegotiate. We test our hypotheses using data on U.S. coal contracts after the policy shock of the 1990 Clean Air Act Amendments. Contracts are divided into two categories, those that were renegotiated following the shock and those that were not. Characteristics of the contract are used to explain whether or not the contract was ultimately renegotiated. Results provide guidance on rent re-distribution and contract renegotiation more generally and are applicable to contemporary policy issues such as climate change legislatio

    773-4 Long Term Efficacy and Safety of Endovascular Low Dose Irradiation In a Swine Model of Restenosis After Angloplasty

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    Restenosis after balloon angioplasty is characterized by neointima formation. We have previously shown that ionizing radiation reduce neointima formation two weeks after angioplasty in a swine model of restenosis. To determine the durability of this effect and the long term safety after endovascular irradiation twenty one miniswine coronary arteries underwent overstretch balloon injury with a 3.5mm angioplasty balloon in the LAD, LCX and RCA. High energy 1921ridium source was introduced immediately by random assignment to deliver 700 or 1400 cGy in 14 injured coronary arteries (LAD and CX). Six months later an angiogram was performed, the animals were killed and the coronary arteries were perfusion fixed. Serial sections were stained with H&E, WG, MT then evaluated by histopathologic and morphometric techniques. Intimal area (IA) and area of intimal thickness corrected for the extent of injury (INFL) was measured in the irradiated and control arteries and compared with pigs that underwent the same treatment but were followed for 2 weeks only.ResultsAll treated arteries were patent with normal angiographic appearance. Lumen diameters at baseline and follow-up were similar. There was no difference in fibrosis at the adventitia, media, perivascular space or adjacent segments of myocardium of the irradiated arteries compared with control.Control700 cGy1400 cGyIN/FL 2Weeks0.59±0.230.42±0.15**0.17±0.16****IN/FL 6 Months0.50±0.20.35±0.18*0.31±0.16**IA 6 Months (mm)1.25±0.250.85±0.47***0.62±0.45**P values: control versus treatment group:*P=0.009**P<0.001***P=0.05.****P<0.0001ConclusionsEndovascular low dose irradiation in this model is safe andthe inhibitory effect of localized radiation on neointimal thickening (restenos is like) response to angioplasty is maintained at six months

    Improved hippocampal dose with reduced margin radiotherapy for glioblastoma multiforme

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    BACKGROUND: To dosimetrically evaluate the effect of reduced margin radiotherapy on hippocampal dose for glioblastoma multiforme (GBM) patients. METHODS: GBM patients enrolled on the Radiation Therapy Oncology Group (RTOG) 0825 trial at our institution were identified. Standard RTOG 0825 expansions were 2 cm + 3-5 mm from the gross tumor volume (GTV) to the clinical tumor volume (CTV) and from the CTV to the planning tumor volume (PTV), respectively. These same patients also had reduced margin tumor volumes generated with 8 mm (GTV to CTV) + 3 mm (CTV to PTV) expansions. Individual plans were created for both standard and reduced margin structures. The dose-volume histograms were statistically compared with a paired, two-tailed Student’s t-test with a significance level of p < 0.05. RESULTS: A total of 16 patients were enrolled on RTOG 0825. The reduced margins resulted in statistically significant reductions in hippocampal dose at all evaluated endpoints. The hippocampal D(max) was reduced from a mean of 61.4 Gy to 56.1 Gy (8.7%), D(40%) was reduced from 49.9 Gy to 36.5 Gy (26.9%), D(60%) was reduced from 32.7 Gy to 18.7 Gy (42.9%) and the D(80%) was reduced from 27.3 Gy to 15.3 Gy (44%). CONCLUSIONS: The use of reduced margin PTV expansions in the treatment of GBM patients results in significant reductions in hippocampal dose. Though the exact clinical benefit of this reduction is currently unclear, this study does provide support for a future prospective trial evaluating the neurocognitive benefits of reduced margin tumor volumes in the treatment of GBM patients

    Integration of computational modeling with membrane transport studies reveals new insights into amino acid exchange transport mechanisms

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    Uptake of system L amino acid substrates into isolated placental plasma membrane vesicles in the absence of opposing side amino acid (zero-trans uptake) is incompatible with the concept of obligatory exchange, where influx of amino acid is coupled to efflux. We therefore hypothesized that system L amino acid exchange transporters are not fully obligatory and/or that amino acids are initially present inside the vesicles. To address this, we combined computational modeling with vesicle transport assays and transporter localization studies to investigate the mechanism(s) mediating [14C]L-serine (a system L substrate) transport into human placental microvillous plasma membrane (MVM) vesicles. The carrier model provided a quantitative framework to test the 2 hypotheses that L-serine transport occurs by either obligate exchange or nonobligate exchange coupled with facilitated transport (mixed transport model). The computational model could only account for experimental [14C]L-serine uptake data when the transporter was not exclusively in exchange mode, best described by the mixed transport model. MVM vesicle isolates contained endogenous amino acids allowing for potential contribution to zero-trans uptake. Both L-type amino acid transporter (LAT)1 and LAT2 subtypes of system L were distributed to MVM, with L-serine transport attributed to LAT2. These findings suggest that exchange transporters do not function exclusively as obligate exchangers.—Widdows, K. L., Panitchob, N., Crocker, I. P., Please, C. P., Hanson, M. A., Sibley, C. P., Johnstone, E. D., Sengers, B. G., Lewis, R. M., Glazier, J. D. Integration of computational modeling with membrane transport studies reveals new insights into amino acid exchange transport mechanisms

    MeerKAT uncovers the physics of an odd radio circle

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    Odd radio circles (ORCs) are recently-discovered faint diffuse circles of radio emission, of unknown cause, surrounding galaxies at moderate redshift (z ∼0.2-0.6). Here, we present detailed new MeerKAT radio images at 1284 MHz of the first ORC, originally discovered with the Australian Square Kilometre Array Pathfinder, with higher resolution (6 arcsec) and sensitivity (∼2.4 μJy/beam). In addition to the new images, which reveal a complex internal structure consisting of multiple arcs, we also present polarization and spectral index maps. Based on these new data, we consider potential mechanisms that may generate the ORCs

    Immunomodulatory Therapy Reduces the Severity of Placental Lesions in Chronic Histiocytic Intervillositis

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    From Frontiers via Jisc Publications RouterHistory: collection 2021, received 2021-08-04, accepted 2021-09-23, epub 2021-10-18Publication status: PublishedChronic histiocytic intervillositis (CHI) is a rare, but highly recurrent inflammatory placental lesion wherein maternal macrophages infiltrate the intervillous space. Pregnancies with CHI are at high risk of fetal growth restriction, miscarriage or stillbirth. Presently, the diagnosis can only be made after histopathological examination of the placenta. Given its proposed immunological etiology, current treatments include aspirin, heparin, and immunomodulatory agents. However, the rationale for these medications is largely based upon small case series and reports as there is a lack of larger studies investigating treatment efficacy. Therefore, this study sought to determine whether inclusion of immunomodulatory medications was effective at reducing the severity of lesions and improving pregnancy outcomes in subsequent pregnancies. Thirty-three women with a history of CHI in at least one pregnancy (index case) were identified retrospectively through medical records. Twenty-eight participants presented with a first subsequent pregnancy and a further 11 with a second subsequent pregnancy at a specialist clinic for pregnancy after loss. Data on maternal demographics, medical history, medication, pregnancy outcome, and placental pathology was collected and compared between pregnancies. Twenty-seven (69%) subsequent pregnancies were treated with at least one or both of prednisolone and hydroxychloroquine. Inclusion of at least one immunomodulatory agent in treatment regimen resulted in an almost 25% increase in overall livebirth rate (61.5 vs. 86.2%). In women treated with immunomodulatory medication a greater proportion of placentas had reduced severity of lesions compared to those treated without (86.7 vs. 33.3%, respectively). A reduction in CHI severity was associated with a 62.3% improvement in livebirth rate compared to those where severity remained unchanged in relation to the index case. These data provide preliminary evidence that the use of immunomodulatory medication in the management of CHI improves histopathological lesions and the chance of livebirth in subsequent pregnancies. Due to CHI's rarity and ethical and feasibility issues, randomized controlled trials in affected women are challenging to conduct. As a result, collaboration between centers is required in future to increase study sample sizes and elucidate the mechanisms of hydroxychloroquine and prednisolone in reducing pathology

    Newfoundland Neogene sediment drifts: transition from the Paleogene greenhouse to the modern icehouse

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    This workshop brought together specialists from various fields to develop a drilling proposal to fill the "Oligo-Miocene Gap" that exists in our understanding of the functions of Earth's systems. We propose to establish the first continuous high-deposition record of the Oligo-Miocene through new International Ocean Discovery Program (IODP) drilling in the North Atlantic to allow the development of a continuous Neogene cyclostratigraphy and to enhance our knowledge of Oligo-Miocene ocean–ice–climate dynamics. The workshop was held in Heidelberg from 15 to 17 September 2014 funded by ESF (EARTHTIME EU), NSF, and the ECORD MagellanPlus Workshop Series Program. A total of 24 participants from six different countries (Australia, France, Germany, the Netherlands, United Kingdom, and United States) attended the workshop, including several early career stage researchers. We discussed certain aspects of Cenozoic paleoceanography and paleoclimate and how the gaps in the Oligo-Miocene could be filled using scientific drilling. The ultimate goal of the workshop (to submit a pre-proposal to IODP) was achieved (IODP Proposal 874-pre was submitted 1 October 2014). Our workshop consisted of overview presentations followed by self-selected breakout groups that discussed different topics and produced text and figures for the proposal. Here, we give a short overview of the major topics discussed during the workshop and the scientific goals presented in the resulting IODP pre-proposal

    The Lantern, 2021-2022

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    No More Buses through El Paso • A Woman\u27s World • The Angel of Tragedy • A Victim of Circumstance • Ace of Hearts • Ghost Light • Missing Diamonds • The Upside-Down House: A Dialogue with the Self • What is Chronic Pain? • A Sunny Day in Sinkhole • Extra Marshmallows • Fourth Wall Broken • Hemlock • In the Comfort of Others • Lasting Impressions • Let\u27s Do the Time Warp Again • One Last Afternoon • Space Invaders • The Dogwood Tree • An Ode to Poppies • Charlotte\u27s Web • Crab • Crossing • Dandelions • Dandelion Sandwich • Grizzly Hood • Help Wanted • I Gave Way • I\u27m not who you wanted but maybe one day I can be • Kneeling • Lemon Cookies • Lies • Method Acting • Moment of Tranquility • Our Home • Overthinking • Sea Glass • Seasonal • Thirty-Two (No Spares) • The Autumn Beast • The Miller\u27s Daughter • Theodore • To the Earring I Left Behind in Your Carpet • Virginia • Waltzing • Yellow House • 1/25 British Monarch • Cracked • In the Shadows • Jewelwing • Life on the Wing • O\u27 Captain my Captain • Stars Above the Bay • The Common Fall • Tom • Cats + Crowshttps://digitalcommons.ursinus.edu/lantern/1190/thumbnail.jp
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