1,391 research outputs found

    Data indexing techniques for the EUVE all-sky survey

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    This poster describes techniques developed for manipulating large full-sky data sets for the Extreme Ultraviolet Explorer project. The authors have adapted the quatrilateralized cubic sphere indexing algorithm to allow us to efficiently store and process several types of large data sets, such as full-sky maps of photon counts, exposure time, and count rates. A variation of this scheme is used to index sparser data such as individual photon events and viewing times for selected areas of the sky, which are eventually used to create EUVE source catalogs

    Breast cancer and communication: Monocentric experience of a self-assessment questionnaire

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    Background: The communication of the diagnosis of breast cancer induces to the patient a strong psychological trauma. Radiologists are at the forefront of communicating, either for a biopsy or the probable diagnosis of malignancy. This is a complex task, which requires the knowledge and application of correct “communicative models”, among which the SPIKES protocol rep-resents a fundamental reference. Design and methods: 110 patients, with a history of breast cancer, filled out a questionnaire consisting of six questions: five aimed at defining communication compliance with the SPIKES protocol, the sixth, consisting of six feelings, aimed at the knowledge of the next emotional state. Results: Regarding compliance with various “strategic points” of the SPIKES protocol, questionnaires show that 70% of patients reported no omissions, while the remaining 30% reported omissions relatively to perception (56%), emotions (23%), setting (13%), knowledge (6%) and invitation (2%). The results showed the existence of a correlation between the final emotional state and the correct application of the SPIKES protocol; in fact, patients who reacted with a positive final emotional state-reported greater adherence to the strategic points of the SPIKES protocol. Conclusions: In healthcare, knowing the communicative compliance of a team in giving “bad news” is fundamental, especially in breast cancer. The SPIKES protocol is recognized by the Literature as a fundamental reference able to affect “positively” the emotional state of patients. The proposed questionnaire is a valid tool to identify the weak points of communication and related criticalities, to improve clinical practice

    Correlated electron-hole plasma in organometal perovskites

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    Organic-inorganic perovskites are a class of solution-processed semiconductors holding promise for the realization of low-cost efficient solar cells and on-chip lasers. Despite the recent attention they have attracted, fundamental aspects of the photophysics underlying device operation still remain elusive. Here we use photoluminescence and transmission spectroscopy to show that photoexcitations give rise to a conducting plasma of unbound but Coulomb-correlated electron-hole pairs at all excitations of interest for light-energy conversion and stimulated optical amplification. The conductive nature of the photoexcited plasma has crucial consequences for perovskite-based devices: in solar cells, it ensures efficient charge separation and ambipolar transport while, concerning lasing, it provides a low threshold for light amplification and justifies a favourable outlook for the demonstration of an electrically driven laser. We find a significant trap density, whose cross-section for carrier capture is however low, yielding a minor impact on device performance

    Block Copolymer Directed Metamaterials and Metasurfaces for Novel Optical Devices

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    Optical metamaterials are artificially engineered architectures that exhibit desired optical properties not found in nature. Bespoke design requires the ability to define shape, size, orientation, and composition of material structures on the nanometer length scale. Bottom-up self-assembly methods, such as block copolymer (BCP) templating, offer unique pathways to tailored features, at spatial resolution not routinely achieved by conventional top-down techniques. In this review, the authors provide the general readership with basic concepts of the underlying fabrication processes and examine optical phenomena arising from BCP-derived metamaterials and nanoresonators, with both dielectric and plasmonic characteristics. A number of diverse structural conformations designed by BCP templating and their implementation in optical devices is evaluated. The discussion includes 3D metamaterials, such as gyroidal and hyperbolic arrangements, as well as 2D metasurfaces. Based on recent developments in exploring these emerging structural and material configurations, the review further highlights unexplored opportunities offered by BCP self-assembly for novel metamaterials and metasurface devices

    Resolved diffraction patterns from a reflection grating for atoms

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    We have studied atomic diffraction at normal incidence from an evanescent standing wave with a high resolution using velocity selective Raman transitions. We have observed up to 3 resolved orders of diffraction, which are well accounted for by a scalar diffraction theory. In our experiment the transverse coherence length of the source is greater than the period of the diffraction grating.Comment: 8 pages, 4 figure

    The Role of Magnesium in Pregnancy and in Fetal Programming of Adult Diseases

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    Magnesium is an essential trace metal and a necessary factor for multiple biochemical functions in humans. Its role in biology is fundamental in over 600 enzymatic reactions implicated in protein synthesis, mitochondrial functions, neuromuscular activity, bone formation, and immune system competence. Magnesium status is relevant in fetal development during gestation and in the newborn growth during the perinatal period. Moreover, magnesium is able to influence fetal programming and disease presentation in childhood or adulthood. The aim of this review is to focus on this metal homeostasis, analyzing its normal values, the causes of hypomagnesemia, the interaction with drugs and other conditions, and the diseases associated with magnesium value alteration during pregnancy, in order to study its role in fetal programming of adult diseases. The data here reported clearly indicated the existence of a connection between magnesium status and human pathology starting from intrauterine life and extending into childhood and adulthood

    Cold atoms in videotape micro-traps

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    We describe an array of microscopic atom traps formed by a pattern of magnetisation on a piece of videotape. We describe the way in which cold atoms are loaded into one of these micro-traps and how the trapped atom cloud is used to explore the properties of the trap. Evaporative cooling in the micro-trap down to a temperature of 1 microkelvin allows us to probe the smoothness of the trapping potential and reveals some inhomogeneity produced by the magnetic film. We discuss future prospects for atom chips based on microscopic permanent-magnet structures.Comment: Submitted for EPJD topical issue "Atom chips: manipulating atoms and molecules with microfabricated structures

    Carotid artery endarterectomy in patients with symptomatic non-stenotic carotid artery disease

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    Object We sought to determine the safety and efficacy in secondary stroke prevention of carotid endarterectomy (CEA) in patients with symptomatic non-stenotic carotid artery disease (SyNC). Methods This was a single-centre retrospective case series. All patients who underwent CEA for unilateral anterior circulation cerebrovascular events with ipsilateral <50% carotid stenosis from 2002 to 2020 were included. Imaging hallmarks including the degree of luminal stenosis and the presence of various vulnerable plaque characteristics (eg, intraplaque haemorrhage (IPH) on MR angiography, ulceration or low-density plaque on CT angiography) were assessed. The presence of vulnerable plaque characteristics was compared between arteries ipsilateral to the ischaemic event and contralateral arteries. The prevalence of perioperative/intraoperative complications, as well as recurrent ischaemic events at follow-up was determined. Results Thirty-two patients were included in the analysis, of which 25.0% were female. Carotid arteries ipsilateral to an ischaemic event had a significantly higher prevalence of IPH when compared with contralateral arteries (80.0% vs 0.0%; p<0.001). There were no intraoperative complications. One patient (3.1%) developed symptoms of transient ipsilateral ischaemia 1 day following CEA which resolved without treatment. In a median follow-up of 18.0 months (IQR 5.0-36.0), only one patient (3.1%) experienced a transient neurologic deficit with complete resolution (annualised rate of recurrent stroke after CEA of 1.5% for a total follow-up of 788 patient-months following CEA). All other patients (31/32, 96.9%) were free of recurrent ischaemic events. Conclusion CEA appears to be safe and well-tolerated in patients with SyNC. Additional studies with larger cohorts and longer follow-up intervals are needed in order to determine the role of CEA in this patient population

    Estimation of protein requirements in Indian pregnant women using a whole-body potassium counter

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    Background: The 2007 World Health Organization/Food and Agriculture Organization/United Nations University (WHO/FAO/UNU) recommendation for the Estimated Average Requirement (EAR) of additional protein during pregnancy for a gestational weight gain (GWG) of 12 kg (recalculated from a GWG of 13.8 kg) is 6.7 and 21.7 g/d in the second and the third trimester, respectively. This EAR is based on measurements of potassium accretion in high-income country (HIC) pregnant women. It is not known if low- to middle-income country, but well-nourished, pregnant women have comparable requirements. Objective: We aimed to estimate total body potassium (TBK) accretion during pregnancy in Indian pregnant women, using a whole-body potassium counter (WBKC), to measure their additional protein EAR. Methods: Well-nourished pregnant women (20–40 y, n = 38, middle socioeconomic stratum) were recruited in the first trimester of pregnancy. Anthropometric, dietary, and physical activity measurements, and measurements of TBK using a WBKC, were performed at each trimester and at birth. Results: The mid-trimester weight gain was 2.7 kg and 8.0 kg in the second and the third trimester, respectively, for an average 37-wk GWG of 10.7 kg and a mean birth weight of 3.0 kg. Protein accretion was 2.7 and 5.7 g/d, for an EAR of 8.2 and 18.9 g/d in the second and the third trimester, respectively. The additional protein EAR, calculated for a GWG of 12 kg, was 9.1 and 21.2 g/d in the second and the third trimester, respectively. Conclusion: The additional protein requirements of well-nourished Indian pregnant women for a GWG of 12 kg in the second and third trimesters were similar to the recalculated 2007 WHO/FAO/UNU requirements for 12 kg

    Low-Dose T-3 Replacement Restores Depressed Cardiac T-3 Levels, Preserves Coronary Microvasculature and Attenuates Cardiac Dysfunction in Experimental Diabetes Mellitus

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    Thyroid dysfunction is common in individuals with diabetes mellitus (DM) and may contribute to the associated cardiac dysfunction. However, little is known about the extent and pathophysiological consequences of low thyroid conditions on the heart in DM. DM was induced in adult female Sprague Dawley (SD) rats by injection of nicotinamide (N; 200 mg/kg) followed by streptozotocin (STZ; 65 mg/kg). One month after STZ/N, rats were randomized to the following groups (N = 10/group): STZ/N or STZ/N + 0.03 g/mL T-3; age-matched vehicle-treated rats served as nondiabetic controls (C). After 2 months of T-3 treatment (3 months post-DM induction), left ventricular (LV) function was assessed by echocardiography and LV pressure measurements. Despite normal serum thyroid hormone (TH) levels, STZ/N treatment resulted in reductions in myocardial tissue content of THs (T-3 and T-4 : 39% and 17% reduction versus C, respectively). Tissue hypothyroidism in the DM hearts was associated with increased DIO3 deiodinase (which converts THs to inactive metabolites) altered TH transporter expression, reexpression of the fetal gene phenotype, reduced arteriolar resistance vessel density, and diminished cardiac function. Low-dose T-3 replacement largely restored cardiac tissue TH levels (T-3 and T-4 : 43% and 10% increase versus STZ/N, respectively), improved cardiac function, reversed fetal gene expression and preserved the arteriolar resistance vessel network without causing overt symptoms of hyperthyroidism. We conclude that cardiac dysfunction in chronic DM may be associated with tissue hypothyroidism despite normal serum TH levels. Low-dose T-3 replacement appears to be a safe and effective adjunct therapy to attenuate and/or reverse cardiac remodeling and dysfunction induced by experimental DM
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