2,972 research outputs found

    Two successful pregnancies following fertility preservation in a patient with anaplastic astrocytoma: a case report

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    Abstract Background Astrocytomas are the most common malignant glial tumors. With improved prognosis, it is possible for patients to pursue pregnancy post-treatment. However, with potential gonadotoxicity of oncology treatments, fertility preservation prior to chemotherapy and/or radiation therapy should be considered. This requires close collaboration between the oncologist and reproductive endocrinologist. To our knowledge this is the first report of successful pregnancies following fertility preservation for AA. Case presentation 33-year-old nulligravid woman with newly diagnosed anaplastic astrocytoma (AA; WHO grade III, IDH1-negative) sought fertility preservation. Prior to chemotherapy and radiation for AA, the patient underwent in vitro fertilization (IVF) for fertility preservation, resulting in 8 vitrified embryos. Following chemo-radiation, the patient underwent two rounds of frozen embryo transfers (FET), each resulting in a successful singleton pregnancy. Conclusion This case illustrates the realistic possibility, in carefully selected patients with brain tumors, of oocyte or embryo cryo-preservation prior to chemo-radiation and subsequent pregnancies

    Signatures of four-particle correlations associated with exciton-carrier interactions in coherent spectroscopy on bulk GaAs

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    Transient four-wave mixing studies of bulk GaAs under conditions of broad bandwidth excitation of primarily interband transitions have enabled four-particle correlations tied to degenerate (exciton-exciton) and nondegenerate (exciton-carrier) interactions to be studied. Real two-dimensional Fourier-transform spectroscopy (2DFTS) spectra reveal a complex response at the heavy-hole exciton emission energy that varies with the absorption energy, ranging from dispersive on the diagonal, through absorptive for low-energy interband transitions to dispersive with the opposite sign for interband transitions high above band gap. Simulations using a multilevel model augmented by many-body effects provide excellent agreement with the 2DFTS experiments and indicate that excitation-induced dephasing (EID) and excitation-induced shift (EIS) affect degenerate and nondegenerate interactions equivalently, with stronger exciton-carrier coupling relative to exciton-exciton coupling by approximately an order of magnitude. These simulations also indicate that EID effects are three times stronger than EIS in contributing to the coherent response of the semiconductor

    Design of a Linear Time-Varying Cross-Coupled Iterative Learning Controller

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    In many manufacturing applications contour tracking is more important than individual axis tracking. Many control techniques, including iterative learning control (ILC), target individual axis error. Because individual axis error only indirectly relates to contour error, these approaches may not be very effective for contouring applications. Cross-coupled ILC (CCILC) is a variation on traditional ILC that targets the contour tracking directly. In contour trajectories with rapid changes, high frequency control is necessary in order to meet tracking requirements. This paper presents an improved CCILC that uses a linear time-varying (LTV) filter to provide high frequency control for short durations. The improved CCILC is designed for raster-scan tracking on a Cartesian robotic test platform. Analysis and experimental results are presented

    Laser Line Scan Characterization of Geometric Profiles in Laser Metal Deposition

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    Laser Metal Deposition (LMD) is an additive manufacturing process in which material is deposited by blowing powdered metal into a melt pool formed by a laser beam. When fabricating parts, the substrate is subjected to motion control such that the melt pool traces a prescribed path to form each part layer. Advantages of LMD include relatively efficient powder usage, the ability to create functionally-graded parts and the ability to repair high-value parts. The process, however, is sensitive to variations in process parameters and a need for feedback measurements and closed-loop control has been recognized in the literature [1, 2]. To this end, a laser line scanner is being integrated into an LMD system at the Missouri University of Science and Technology. Measurements from the laser line scanner will provide the feedback data necessary for closed-loop control of the process. The work presented here considers characteristics of the laser line scanner as it relates to scanning LMD depositions. Errors associated with the measurement device are described along with digital processing operations designed to remove them. The parameter bead height is extracted from scans for future use in a closed-loop control strategy

    Being an Early-Career CMS Academic in the Context of Insecurity and ‘Excellence’: The Dialectics of Resistance and Compliance

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    Drawing on a dialectical approach to resistance, we conceptualise the latter as a multifaceted, pervasive and contradictory phenomenon. This enables us to examine the predicament in which early-career Critical Management Studies academics find themselves in the current times of academic insecurity and ‘excellence’, as gleaned through this group’s understandings of themselves as resisters and participants in the complex and contradictory forces constituting their field. We draw on 24 semi-structured interviews to map our participants’ accounts of themselves as resisters in terms of different approaches to tensions and contradictions between, on the one hand, the interviewees’ Critical Management Studies alignment and, on the other, the ethos of business school neoliberalism. Emerging from this analysis are three contingent and interlinked narratives of resistance and identity – diplomatic, combative and idealistic – each of which encapsulates a particular mode (negotiation, struggle, and laying one’s own path) of engaging with the relationship between Critical Management Studies and the business school ethos. The three narratives show how early-career Critical Management Studies academics not only use existing tensions, contradictions, overlaps and alliances between these positions to resist and comply with selected forces within each, but also contribute to the (re-)making of such overlaps, alliances, tensions and contradictions. Through this reworking of what it means to be both Critical Management Studies scholars and business school academics, we argue, early-career Critical Management Studies academics can be seen as active resisters and re-constituters of their complex field

    Surgical valvulotomy for tricuspid valve stenosis in a dog

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    A 2 year 4 month old female neutered Labrador retriever was presented for evaluation right sided congestive heart failure. Echocardiographic examination revealed tricuspid valve dysplasia with only two small orifices in the valve resulting in severe tricuspid stenosis. The dog underwent a right fifth lateral intercostal thoracotomy and surgical tricuspid valvulotomy, under cardiopulmonary bypass. The stenosis was relieved by dividing the valve leaflets between the two orifices with continuation to the commissures, creating a ‘bi-leaflet’ valve. The dog made a good recovery initially with echocardiography at 48 hours after surgery showing a reduction in tricuspid valve E and A wave velocities and pressure half time (from 230 ms to to 65 ms). She was discharged five days after surgery with spironolactone, benazepril, pimobendan and clopidogrel. The dog was re-presented two days later having collapsed, with pyrexia, facial swelling and pitting edema on the ventral neck and intermandibular region. Investigations did not reveal an underlying cause and the clinical signs resolved with supportive therapy. Two years after surgery the dog was free of clinical signs with normal exercise tolerance and only mild tricuspid regurgitation on echocardiography, with discontinuation of all medications

    Solid-phase phosphorus speciation in Saharan Bodélé depression dusts and source sediments

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    Phosphorus (P) is one of the most important limiting nutrients for the growth of oceanic phytoplankton and terrestrial ecosystems, which in turn contributes to CO2 sequestration. The solid-phase speciation of P will influence its solubility and hence its availability to such ecosystems. This study reports on the results of X-ray diffraction, electron microprobe chemical analysis and X-ray mapping, chemical extractions and X-ray absorption near-edge spectroscopy analysis carried out to determine the solid-phase speciation of P in dusts and their source sediments from the Saharan BodĂ©lĂ© Depression, the world’s largest single source of dust. Chemical extraction data suggest that the BodĂ©lĂ© dusts contain 28 to 60% (mean 49%) P sorbed to, or co-precipitated with Fe (hydr)oxides, < 10% organic P, 21-50% (mean 32%) detrital apatite P, and 10-22% (mean 15%) authigenic-biogenic apatite P. This is confirmed by the other analyses, which also suggest that the authigenic-biogenic apatite P is likely fish bone and scale, and that this might form a larger proportion of the apatite pool (33 +/− 22%) than given by the extraction data. This is the first-ever report of fish material in aeolian dust, and it is significant because P derived from fish bone and scale is relatively soluble and is often used as a soil fertilizer. Therefore, the fish-P will likely be the most readily form of BodĂ©lĂ© P consumed during soil weathering and atmospheric processing, but given time and acid dissolution, the detrital apatite, Fe-P and organic-P will also be made available. The BodĂ©lĂ© dust input of P to global ecosystems will only have a limited life, however, because its major source materials, diatomite in the BodĂ©lĂ© Depression, undergo persistent deflation and have a finite thickness

    Quenched nematic criticality separating two superconducting domes in an iron-based superconductor under pressure

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    The nematic electronic state and its associated nematic critical fluctuations have emerged as potential candidates for superconducting pairing in various unconventional superconductors. However, in most materials their coexistence with other magnetically-ordered phases poses significant challenges in establishing their importance. Here, by combining chemical and hydrostatic physical pressure in FeSe0.89_{0.89}S0.11_{0.11}, we provide a unique access to a clean nematic quantum phase transition in the absence of a long-range magnetic order. We find that in the proximity of the nematic phase transition, there is an unusual non-Fermi liquid behavior in resistivity at high temperatures that evolves into a Fermi liquid behaviour at the lowest temperatures. From quantum oscillations in high magnetic fields, we trace the evolution of the Fermi surface and electronic correlations as a function of applied pressure. We detect experimentally a Lifshitz transition that separates two distinct superconducting regions: one emerging from the nematic electronic phase with a small Fermi surface and strong electronic correlations and the other one with a large Fermi surface and weak correlations that promotes nesting and stabilization of a magnetically-ordered phase at high pressures. The lack of mass divergence suggests that the nematic critical fluctuations are quenched by the strong coupling to the lattice. This establishes that superconductivity is not enhanced at the nematic quantum phase transition in the absence of magnetic order.Comment: 4 figures, 9 page
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