28 research outputs found

    Computed Tomography With Intravenous Contrast Alone: The Role of Intra‐abdominal Fat on the Ability to Visualize the Normal Appendix in Children

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    Background Computed tomography ( CT ) with enteric contrast is frequently used to evaluate children with suspected appendicitis. The use of CT with intravenous ( IV ) contrast alone ( CT IV ) may be sufficient, however, particularly in patients with adequate intra‐abdominal fat ( IAF ). Objectives The authors aimed 1) to determine the ability of radiologists to visualize the normal (nondiseased) appendix with CT IV in children and to assess whether IAF adequacy affects this ability and 2) to assess the association between IAF adequacy and patient characteristics. Methods This was a retrospective 16‐center study using a preexisting database of abdominal CT scans. Children 3 to 18 years who had CT IV scan and measured weights and for whom appendectomy history was known from medical record review were included. The sample was chosen based on age to yield a sample with and without adequate IAF . Radiologists at each center reread their site's CT IV scans to assess appendix visualization and IAF adequacy. IAF was categorized as “adequate” if there was any amount of fat completely surrounding the cecum and “inadequate” if otherwise. Results A total of 280 patients were included, with mean age of 10.6 years (range = 3.1 to 17.9 years). All 280 had no history of prior appendectomy; therefore, each patient had a presumed normal appendix. A total of 102 patients (36.4%) had adequate IAF . The proportion of normal appendices visualized with CT IV was 72.9% (95% confidence interval [ CI ] = 67.2% to 78.0%); the proportions were 89% (95% CI  = 81.5% to 94.5%) and 63% (95% CI  = 56.0% to 70.6%) in those with and without adequate IAF (95% CI for difference of proportions = 16% to 36%). Greater weight and older age were strongly associated with IAF adequacy (p < 0.001), with weight appearing to be a stronger predictor, particularly in females. Although statistically associated, there was noted overlap in the weights and ages of those with and without adequate IAF . Conclusions Protocols using CT with IV contrast alone to visualize the appendix can reasonably include weight, age, or both as considerations for determining when this approach is appropriate. However, although IAF will more frequently be adequate in older, heavier patients, highly accurate prediction of IAF adequacy appears challenging solely based on age and weight. Resumen Tomografía Computarizada Únicamente con Contraste Intravenoso: El Papel de la Grasa Intrabadominal en la Capacidad para Visualizar el Apéndice Normal en los Niños Introduction La tomografía computarizada ( TC ) con contraste entérico es usada frecuentemente para evaluar a los niños con sospecha de apendicitis. El uso de la TC únicamente con contraste intravenoso ( TC IV ) puede ser suficiente, especialmente en pacientes con adecuada grasa intrabdominal ( GIA ). Objetivos 1) Determinar la capacidad de los radiólogos para visualizar el apéndice normal (sin enfermedad) con TC IV en niños, y valorar si la cantidad de GIA afecta a esta capacidad; y 2) valorar la asociación entre la idoneidad de la GIA y las características del paciente. Metodología Estudio retrospectivo de 16 hospitales que utilizó una base de datos prexistente de TC abdominales. Se incluyó a los niños entre 3 y 18 años que tenían una TC IV , una medida del peso e historia de apendectomía conocida por la revisión de la historia clínica. La muestra se eligió en base a la edad con el fin de conseguir una muestra con y sin GIA adecuada. Los radiólogos de cada centro releyeron las TC IV de sus centros para valorar la visualización del apéndice y la adecuación de la GIA . La GIA se clasificó como “adecuada” si había cualquier cantidad de grasa completamente alrededor del ciego e “inadecuada” si era de otra manera. Resultados Se incluyeron 280 pacientes, con una media de edad de 10,6 años (rango 3,1 a 17,9 años). Ninguno tenía historia previa de apendectomía; por lo tanto todos los pacientes tuvieron un apéndice presumiblemente normal. Ciento dos pacientes (36,4%) tuvieron GIA adecuada. El porcentaje de apéndices normales visualizados con TC IV fue de 72,9% ( IC 95% = 67,2% a 78,0%); la proporción fue 89% ( IC 95% = 81,5% a 94,5%), y 63% ( IC 95% = 56,0% a 70,6%) en aquéllos con y sin GIA adecuada ( IC 95% para la diferencia de proporciones = 16% a 36%). El mayor peso y la mayor edad se asociaron fuertemente con la adecuación de la GIA (p < 0,001), y el peso resultó ser el mayor factor predictivo, especialmente en mujeres. Aunque se asoció estadísticamente, se vio un solapamiento en los pesos y edades de aquéllos con y sin GIA adecuada. Conclusiones Los protocolos que usan la TC IV para visualizar el apéndice pueden razonablemente incluir el peso, la edad, o ambas como consideraciones para determinar cuándo esta aproximación es apropiada. Sin embargo, aunque la cantidad de GIA será frecuentemente más apropiada en los pacientes más mayores y de mayor peso, la predicción certera de adecuación de GIA es altamente desafiante si se basa sólo en la edad y el peso.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/99695/1/acem12185.pd

    Quadrupole moments of odd-A ⁵³⁻⁶³Mn: Onset of collectivity towards N = 40

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    The spectroscopic quadrupole moments of the odd–even Mn isotopes between N=28 and N=38 have been measured using bunched-beam collinear laser spectroscopy at ISOLDE, CERN. In order to increase sensitivity to the quadrupole interaction, the measurements have been done using a transition in the ion rather than in the atom, with the additional advantage of better spectroscopic efficiency. Since the chosen transition is from a metastable state, optical pumping in ISOLDE’s cooler and buncher (ISCOOL) was used to populate this state. The extracted quadrupole moments are compared to large-scale shell model predictions using three effective interactions, GXPF1A, LNPS and modified A3DA. The inclusion of both the 1νg9/2and 2νd5/2orbitals in the model space is shown to be necessary to reproduce the observed increase in the quadrupole deformation from N=36 onwards. Specifically, the inclusion of the 2νd5/2orbital induces an increase in neutron and proton excitations across the reduced gaps at N=40and Z=28, leading to an increase in deformation above N=36

    Nuclear charge radii of ⁶²⁻⁸⁰Zn and their dependence on cross-shell proton excitations

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    Nuclear charge radii of ⁶²⁻⁸⁰Zn have been determined using collinear laser spectroscopy of bunched ion beams at CERN-ISOLDE. The subtle variations of observed charge radii, both within one isotope and along the full range of neutron numbers, are found to be well described in terms of the proton excitations across the Z = 28 shell gap, as predicted by large-scale shell model calculations. It comprehensively explains the changes in isomer-to-ground state mean square charge radii of ⁶⁹⁻⁷⁹Zn, the inversion of the odd-even staggering around N = 40 and the odd-even staggering systematics of the Zn charge radii. With two protons above Z = 28, the observed charge radii of the Zn isotopic chain show a cumulative effect of different aspects of nuclear structure including single particle structure, shell closure, correlations and deformations near the proposed doubly magic nuclei, ⁶⁸Ni and ⁷⁸Ni

    Collinear Laser Spectroscopy of Manganese Isotopes using the Radio Frequency Quadrupole Cooler and Buncher at ISOLDE

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    The hyperfine structure of the odd-even 5163^{51−63}Mn isotopes (N = 26 − 38) were measured using bunched beam collinear laser spectroscopy with the COLLAPS experimental setup at ISOLDE, CERN. The properties of these nuclei were investigated over the course of two experiments. During the first experiment, nuclear spins and magnetic dipole moments were extracted from spectroscopy on manganese atoms. These nuclear properties were then compared to the predictions of two large-scale shell model effective interactions (GXPF1A [1, 2] and LNPS [3]) which use different model spaces. In the case of 61,63^{61,63}Mn, these results show the increasing importance of neutron excitations across the proposed N = 40 subshell closure, and of proton excitations across the Z = 28 shell gap. These measurements provide the first direct proof that proton and neutron excitations across shell gaps are playing an important role in the ground state wave functions of the neutron-rich Mn isotopes. The electric quadrupole moment provides complementary information to the magnetic dipole moment, since it is able to directly probe the degree of collectivity and deformation in a nucleus, however sensitivity limitations during the first experiment prevented the quadrupole moments from being accurately determined. To overcome these limitations, it was necessary to find an electronic transition with sensitivity to the quadrupole interaction. A suitable transition was found in the ion from a metastable state and optical pumping in ISOLDE’s cooler and buncher, ISCOOL, was used to populate this state for the second manganese experiment. This is the first use of the in-cooler optical pumping technique at ISOLDE, and required an overhaul of ISCOOL. During the second experiment, the spectroscopic quadrupole moments of the isotopes were extracted from the measured hyperfine spectra of manganese ions. The sensitivity and spectroscopic efficiency were increased as compared to the atomic experiment. The extracted quadrupole moments were again compared to predictions from the GXPF1A and LNPS effective interactions. The inclusion of the 1νg9/21 \nu g_{9/2} and 2νd5/22\nu d_{5/2} orbitals in the model space were shown to be necessary to reproduce the experimentally observed onset of quadrupole deformation

    Upgrade of the radio frequency quadrupole cooler and buncher for the HIE-ISOLDE project

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    The upgrade to the ISOLDE facility, HIE-ISOLDE, will include an upgrade to the RFQCB (radio frequency quadrupole cooler and buncher), the focus of which will be fixing the problems of alignment with the current machine, improving the integrity of the vacuum system, stabilizing the internal gas pressure, and the changes associated with a new position. The beam passage inside the RFQCB has been simulated with an independent code to highlight the importance of the internal gas pressure, to motivate design changes in the new RFQCB and to explain ways to improve the performance of the current machine. The suspected misalignment of ISCOOL has been quantified, and, using a simulation of ions passing through the external injection electrodes, the effect of the misalignment on machine acceptance has been detailed. Plans for the future RFQCB test stand and HIE-ISOLDE installation have been outlined. (C) 2013 Elsevier B.V. All rights reserved

    The Relation Between Borderline Personality Disorder Features and Teen Dating Violence

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    Objective: Teen dating violence (TDV) is a serious social problem with significant physical and emotional consequences. A number of theoretical models have identified several factors associated with intimate partner violence (IPV) among adults, including the role of Axis II features such as borderline personality disorder (BPD). However, little is known about borderline features and intimate partner violence among adolescents (i.e., TDV). The present study is the first to investigate the relation between TDV and borderline features in adolescents, taking into account important additional correlates of TDV at the cross-sectional level. Method: An ethnically diverse sample of 778 adolescents completed self-report measures of dating violence, borderline features, alcohol use, and exposure to interparental violence. Results: Borderline features made independent contributions to both TDV victimization and perpetration. The association between borderline features and TDV victimization was moderated by gender, and when considering severe violence, gender moderated the relation between borderline features and both TDV victimization and perpetration. Conclusions: Borderline features should be considered in the assessment, prevention, and intervention of TDV and vice versa. Keywords: adolescence, borderline personality disorder, perpetration, teen dating violence, victimization Teen dating violence (TDV) is a significant social problem with an alarmingly high prevalence rate (Centers for Disease Control and Prevention, 2012). It is estimated that 10% to 20% of adolescents have experienced &quot;severe&quot; physical dating violence Given the physical and emotional costs of TDV, including the increased risk for perpetuating the intergenerational transmission of interpersonal violence Explaining TDV/Intimate Partner Violence (IPV): Theoretical Framework and Empirical Support Recent comprehensive etiological models posit a number of important factors that may explain aggressive and abusive behaviors between partners. For example, Bell and Naugle (2008) proposed a comprehensive model of IPV that recognizes the significant heterogeneity of and widens the scope of possible predictors for IPV by including factors such as personality traits, exposure to interparental violence, and substance use. With respect to this model, research has confirmed significant associations with TDV/ IPV and exposure to interparental violenc

    Production of Radioactive Molecular Ions in Radiofrequency Quadrupole Gas-Reaction Cells

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    Limited types of radioactive molecules (RM) can be made inside hot-cavity targets at ISOL facilities like TRIUMF. However, extreme conditions in these targets present formidable unsolved challenges to efficient production and delivery of RM’s. Here we propose using RFQ gas-reaction cells to produce RM from radioactive ion beams (RIB) by room temperature RIB-gas chemical reactions at eV energies. Two options are possible: (1) using an ion reaction cell (IRC) that is a linear RFQ ion guide and reaction cell used as an ‘on-line ion source’, and (2) using the ARIEL RFQ cooler-buncher (ARQB). RFQ gas-cells are a controllable and efficient method to produce RM from chemical reactants that cannot be used in ISOL targets. This ‘online chemistry’ offers a way to enable groundbreaking Beyond Standard Model (BSM) physics research, using a wide diversity of new rare and exotic RM beams that would be difficult or impossible to produce in hot-cavity targets
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