Suspicion of Acute Appendicitis in the Third Trimester of Pregnancy: Pros and Cons of a Laparoscopic Procedure

This review suggests that diagnostic laparoscopy during the third trimester of pregnancy is a logical strategy to minimize maternal and fetal risk when acute appendicitis is suspected

High-quality epitaxial iron nitride films grown by gas-assisted molecular-beam epitaxy

Thin films of γ’-Fe4N were grown on polished (001) MgO substrates by molecular-beam epitaxy of iron in the presence of a gas flow from a rf atomic source. By means of x-ray diffraction, Mössbauer Spectroscopy, Rutherford backscattering/channeling, and scanning probe microscopy, it is shown that, with this method, single-phase, high-quality epitaxial thin films can be grown with a very smooth surface (root-mean-square roughness ∼0.4 nm). Magnetic measurements reveal square hysteresis loops, moderate coercivities (45 Oe for a 33 nm thick film) and complete in-plane orientation of the magnetization. These properties make the films interesting candidates for device applications

Aneurysm of the Superior Posterior Pancreatic-Duodenal Artery Presenting with Recurrent Syncopes

We present a 61-year-old woman with hypovolemic shock due to a ruptured aneurysm of the superior posterior pancreatic-duodenal artery in whom recurrent syncopes were the first presenting sign of pancreatic-duodenal artery aneurysm (PDAA). PDAA is a rare but life-threatening condition. The widely varying symptomatology may lead to a delay in diagnosis and treatment. Patients with atypical symptoms, such as vague abdominal pain, recurrent dizziness or syncope, may actually suffer from a sentinel bleeding of the vascular malformation. Radiological imaging, especially selective angiography, may provide a diagnostic as well as a therapeutic tool in these patients

New strategies for HIV surveillance in resource-constrained settings: an overview.

Additional funding recently became available to help resource-constrained countries scale up their HIV treatment and prevention activities. This increased funding is accompanied by an increased demand for accountability from stakeholders. Many countries will need to make substantial improvements in their current HIV surveillance methods to monitor the collective national impact of these treatment and prevention initiatives. However, whereas most resource-constrained countries have monitored the prevalence of HIV, they have collected little information on other events in the HIV disease process, such as HIV incidence, rate of HIV drug resistance, number of deaths due to AIDS and only modest emphasis has been placed on AIDS reporting in generalized epidemics, resulting in severe underreporting. In addition, data on mortality trends are often not gathered. Furthermore, less than half of the countries with low-level/concentrated epidemics have tailored their surveillance systems to the local epidemic, behavioral surveillance is often not present, an integrated analysis of data is not widespread, and data are rarely used to inform policy. In January 2004, a conference was convened in Addis Ababa, Ethiopia, to examine new strategies for surveillance in resource-constrained countries, and their use in monitoring and evaluating HIV activities. This supplement summarizes the newest approaches and lessons learned for HIV/AIDS surveillance, based on presentations and discussions from that conference. This article provides an overview of HIV/AIDS surveillance in resource-constrained settings and discusses the history, current approaches, and future directions for HIV/AIDS surveillance in generalized and low-level/concentrated epidemics

Shower approach in the simulation of ion scattering from solids

An efficient approach for the simulation of ion scattering from solids is proposed. For every encountered atom, we take multiple samples of its thermal displacements among those which result in scattering with high probability to finally reach the detector. As a result, the detector is illuminated by intensive "showers", where each event of detection must be weighted according to the actual probability of the atom displacement. The computational cost of such simulation is orders of magnitude lower than in the direct approach and a comprehensive analysis of multiple and plural scattering effects becomes possible. We use the new method for two purposes. First, the accuracy of the approximate approaches, developed mainly for ion-beam structural analysis, is verified. Second, the possibility to reproduce a wide class of experimental conditions is used to analyze some basic features of ion-solid collisions: the role of double violent collisions in low-energy ion scattering; the origin of the "surface peak" in scattering from amorphous samples; the low-energy tail in the energy spectra of scattered medium-energy ions due to plural scattering; the degradation of blocking patterns in 2D angular distributions with increasing depth of scattering. As an example of simulation for ions of MeV energies, we verify the time-reversibility for channeling/blocking of 1 MeV protons in a W crystal. The possibilities of analysis that our approach offers may be very useful for various applications in particular for structural analysis with atomic resolution.Comment: 16 pages, 9 figures. Finally published version; large parts reformulated, Fig. 9 and references adde

Improvement of Sidestream Dark Field Imaging with an Image Acquisition Stabilizer

Background: In the present study we developed, evaluated in volunteers, and clinically validated an image acquisition stabilizer (IAS) for Sidestream Dark Field (SDF) imaging.Methods: The IAS is a stainless steel sterilizable ring which fits around the SDF probe tip. The IAS creates adhesion to the imaged tissue by application of negative pressure. The effects of the IAS on the sublingual microcirculatory flow velocities, the force required to induce pressure artifacts (PA), the time to acquire a stable image, and the duration of stable imaging were assessed in healthy volunteers. To demonstrate the clinical applicability of the SDF setup in combination with the IAS, simultaneous bilateral sublingual imaging of the microcirculation were performed during a lung recruitment maneuver (LRM) in mechanically ventilated critically ill patients. One SDF device was operated handheld; the second was fitted with the IAS and held in position by a mechanic arm. Lateral drift, number of losses of image stability and duration of stable imaging of the two methods were compared.Results: Five healthy volunteers were studied. The IAS did not affect microcirculatory flow velocities. A significantly greater force had to applied onto the tissue to induced PA with compared to without IAS (0.25 ± 0.15 N without vs. 0.62 ± 0.05 N with the IAS, p < 0.001). The IAS ensured an increased duration of a stable image sequence (8 ± 2 s without vs. 42 ± 8 s with the IAS, p < 0.001). The time required to obtain a stable image sequence was similar with and without the IAS. In eight mechanically ventilated patients undergoing a LRM the use of the IAS resulted in a significantly reduced image drifting and enabled the acquisition of significantly longer stable image sequences (24 ± 5 s without vs. 67 ± 14 s with the IAS, p = 0.006).Conclusions: The present study has validated the use of an IAS for improvement of SDF imaging by demonstrating that the IAS did not affect microcirculatory perfusion in the microscopic field of view. The IAS improved both axial and lateral SDF image stability and thereby increased the critical force required to induce pressure artifacts. The IAS ensured a significantly increased duration of maintaining a stable image sequence

Disparity between skin perfusion and sublingual microcirculatory alterations in severe sepsis and septic shock: a prospective observational study

Objective: Measurement of central-to-toe temperature difference has been advocated as an index of severity of shock and as a guide for circulatory therapy in critically ill patients. However, septic shock, in contrast to other forms of shock, is associated with a distributive malfunction resulting in a disparity between vascular compartments. Although this disparity has been established between systemic and microcirculatory parameters, it is unclear whether such disparity exists between skin perfusion and microcirculation. To test this hypothesis of disparity, we simultaneously measured parameters of the two vascular compartments, in the early phase of sepsis. Design: Prospective observational study in patients with severe sepsis/septic shock in the first 6 h of ICU admission. Simultaneous measurements of central-to-toe temperature difference and sublingual microcirculatory orthogonal polarization spectral imaging, together with parameters of systemic hemodynamics. Setting: 22 bed mixed-ICU in a tertiary teaching hospital. Patients: 35 consecutive patients in a 12-month period. Measurements and results: In 35 septic patients and a median APACHE II score of 20, no correlation between central-to-toe temperature gradient and microvascular flow index was observed (r(s) =-0.08, p = 0.65). Also no significant correlation between temperature gradient/microvascular flow index and systemic hemodynamic parameters could be demonstrated. Conclusions: During the early phase of resuscitated severe sepsis and septic shock there appears to be no correlation between sublingual microcirculatory alterations and the central-to-toe temperature difference. This finding adds to the concept of a dispersive nature of blood flow under conditions of sepsis between microcirculatory and systemic hemodynamic

Structure and magnetism of single-phase epitaxial γ′-Fe4N

Single phase epitaxial pure γ′-Fe4N films are grown on MgO (001) by molecular beam epitaxy of iron in the presence of nitrogen obtained from a radio frequency atomic source. The epitaxial, single phase nature of the films is revealed by x-ray diffraction and by the local magnetic environment investigated by Mössbauer spectroscopy. The macroscopic magnetic properties of the γ′-Fe4N films are studied in detail by means of transverse Kerr effect measurements. The hysteresis loops are consistent with the cubic atomic structure, displaying easy [100] magnetization directions. The films are single domain at remanence, and the reversal is dominated by 180° or 90° domain wall nucleation and propagation, depending on the applied field direction. When 90° domain walls are responsible for the magnetization reversal, this proceeds in two stages, and the measured coercive fields vary accordingly. Magnetic domain observations reveal the two distinct reversal —driven by 180° or 90° domain walls— modes displaying large domains, of the order of mm. From magnetometer techniques, the saturation magnetization, μ0Ms, is measured to be 1.8 T. A magneto-optical torque technique is used to obtain a value of the anisotropy constant of 2.9×104J/m3.The authors acknowledge partial financing from EC project HIDEMAR G5RD-CT-2002-00731 and PHANTOMS network. The authors are indebted to A. Gupta and K. V. Rao from the department of Materials Science and Engineering, KTH, Sweden for help with the low T SQUID measurements, and to L. Ballcels and M. A. García from Materials Science ICMM CSIC, Spain for high-T VSM measurements. This work was part of the research program of the Foundation for Fundamental Research on Matter-FOM, The Netherlands. J.M.G.M. acknowledges financing through the Ramón y Cajal program from the Spanish MCyT.Peer reviewe

Growth and properties of Cu3N films and Cu3N/gamma '-Fe4N bilayers

Copper nitride films were grown by molecular-beam epitaxy of copper in the presence of nitrogen from a radio-frequency atomic source on (001) gamma'-Fe4N/(001)MgO or directly on MgO substrates. The structural properties of the Cu3N films were found to be very dependent on the substrate and on the deposition temperature. At optimal growth conditions, the Cu3N films grow epitaxial on both substrates. The Cu3N films grown on MgO were characterized optically to be insulators with an energy gap of 1.65 eV. On gamma'-Fe4N, Cu3N films with a thickness of only 6 nm, were grown as closed layers, epitaxial and rather smooth (root-mean-square roughness of 0.7 nm). This material has ideal properties to be used as a barrier in low resistance magnetic tunnel junctions. (C) 2002 American Institute of Physics

Scaling-up co-trimoxazole prophylaxis in HIV-exposed and HIV-infected children in high HIV-prevalence countries.

Co-trimoxazole (trimethoprim-sulfamethoxazole) is a widely available antibiotic that substantially reduces HIV-related morbidity and mortality in both adults and children. Prophylaxis with co-trimoxazole is a recommended intervention of proven benefit that could serve not only as an initial step towards improving paediatric care in young children with limited access to antiretroviral treatment, but also as an important complement to antiretroviral therapy in resource-limited settings. Despite co-trimoxazole's known clinical benefits, the potential operational benefits, and favourable recommendations by WHO, UNAIDS, and UNICEF, its routine use in developing countries--particularly sub-Saharan Africa--has remained limited. Out of an estimated 4 million children in need of co-trimoxazole prophylaxis (HIV-exposed and HIV-infected), only 4% are currently receiving this intervention. We discuss some of the major barriers preventing the scale-up of co-trimoxazole prophylaxis for children in countries with a high prevalence of HIV and propose specific actions required to tackle these challenges