30 research outputs found

    Computed tomographic assessment of lung weights in trauma patients with early posttraumatic lung dysfunction

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    Introduction: Quantitative computed tomography (qCT)-based assessment of total lung weight (M(lung)) has the potential to differentiate atelectasis from consolidation and could thus provide valuable information for managing trauma patients fulfilling commonly used criteria for acute lung injury (ALI). We hypothesized that qCT would identify atelectasis as a frequent mimic of early posttraumatic ALI. Methods: In this prospective observational study, M(lung) was calculated by qCT in 78 mechanically ventilated trauma patients fulfilling the ALI criteria at admission. A reference interval for M(lung) was derived from 74 trauma patients with morphologically and functionally normal lungs (reference). Results are given as medians with interquartile ranges. Results: The ratio of arterial partial pressure of oxygen to the fraction of inspired oxygen was 560 (506 to 616) mmHg in reference patients and 169 (95 to 240) mmHg in ALI patients. The median reference M(lung) value was 885 (771 to 973) g, and the reference interval for M(lung) was 584 to 1164 g, which matched that of previous reports. Despite the significantly greater median M(lung) value (1088 (862 to 1,342) g) in the ALI group, 46 (59%) ALI patients had M(lung) values within the reference interval and thus most likely had atelectasis. In only 17 patients (22%), Mlung was increased to the range previously reported for ALI patients and compatible with lung consolidation. Statistically significant differences between atelectasis and consolidation patients were found for age, Lung Injury Score, Glasgow Coma Scale score, total lung volume, mass of the nonaerated lung compartment, ventilator-free days and intensive care unit-free days. Conclusions: Atelectasis is a frequent cause of early posttraumatic lung dysfunction. Differentiation between atelectasis and consolidation from other causes of lung damage by using qCT may help to identify patients who could benefit from management strategies such as damage control surgery and lung-protective mechanical ventilation that focus on the prevention of pulmonary complications.Leipzig University Hospita

    2D to 3D crossover of the magnetic properties in ordered arrays of iron oxide nanocrystals

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    The magnetic 2D to 3D crossover behavior of well-ordered arrays of monodomain gamma-Fe2O3 spherical nanoparticles with different thicknesses has been investigated by magnetometry and Monte Carlo (MC) simulations. Using the structural information of the arrays obtained from grazing incidence small-angle X-ray scattering and scanning electron microscopy together with the experimentally determined values for the saturation magnetization and magnetic anisotropy of the nanoparticles, we show that MC simulations can reproduce the thickness-dependent magnetic behavior. The magnetic dipolar particle interactions induce a ferromagnetic coupling that increases in strength with decreasing thickness of the array. The 2D to 3D transition in the magnetic properties is mainly driven by a change in the orientation of the magnetic vortex states with increasing thickness, becoming more isotropic as the thickness of the array increases. Magnetic anisotropy prevents long-range ferromagnetic order from being established at low temperature and the nanoparticle magnetic moments instead freeze along directions defined by the distribution of easy magnetization directions

    Impact of five years of peer-mediated interventions on sexual behavior and sexually transmitted infections among female sex workers in Mombasa, Kenya

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    <p>Abstract</p> <p>Background</p> <p>Since 2000, peer-mediated interventions among female sex workers (FSW) in Mombasa Kenya have promoted behavioural change through improving knowledge, attitudes and awareness of HIV serostatus, and aimed to prevent HIV and other sexually transmitted infection (STI) by facilitating early STI treatment. Impact of these interventions was evaluated among those who attended peer education and at the FSW population level.</p> <p>Methods</p> <p>A pre-intervention survey in 2000, recruited 503 FSW using snowball sampling. Thereafter, peer educators provided STI/HIV education, condoms, and facilitated HIV testing, treatment and care services. In 2005, data were collected using identical survey methods, allowing comparison with historical controls, and between FSW who had or had not received peer interventions.</p> <p>Results</p> <p>Over five years, sex work became predominately a full-time activity, with increased mean sexual partners (2.8 versus 4.9/week; <it>P </it>< 0.001). Consistent condom use with clients increased from 28.8% (145/503) to 70.4% (356/506; <it>P </it>< 0.001) as well as the likelihood of refusing clients who were unwilling to use condoms (OR = 4.9, 95%CI = 3.7–6.6). In 2005, FSW who received peer interventions (28.7%, 145/506), had more consistent condom use with clients compared with unexposed FSW (86.2% versus 64.0%; AOR = 3.6, 95%CI = 2.1–6.1). These differences were larger among FSW with greater peer-intervention exposure. HIV prevalence was 25% (17/69) in FSW attending ≥ 4 peer-education sessions, compared with 34% (25/73) in those attending 1–3 sessions (P = 0.21). Overall HIV prevalence was 30.6 (151/493) in 2000 and 33.3% (166/498) in 2005 (<it>P </it>= 0.36).</p> <p>Conclusion</p> <p>Peer-mediated interventions were associated with an increase in protected sex. Though peer-mediated interventions remain important, higher coverage is needed and more efficacious interventions to reduce overall vulnerability and risk.</p

    Bone transport for limb reconstruction following severe tibial fractures

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    A common treatment of tibial defects especially after infections is bone transport via external fixation. We compare complications and outcomes of 25 patients treated with a typical Ilizarov frame or a hybrid system for bone reconstruction of the tibia. Average follow up was 5.1 years. Particular interest was paid to the following criteria: injury type, comorbidities, development of osteitis and outcome of the different therapies. The reason for segmental resection was a second or third grade open tibia fractures in 24 cases and in one case an infection after plate osteosynthesis. Average age of the patients was 41 years (range 19 to 65 years) and average defect size 6.6 cm (range 3.0 to 13.4 cm). After a mean time of 113 days 23 tibial defects were reconstructed, so we calculated an average healing index of 44.2 days/cm. Two patients with major comorbidities needed a below knee amputation. The presence of osteitis led to a more complicated course of therapy. In the follow up patients with an Ilizarov frame had better results than patients with hybrid systems. Bone transport using external fixation is suitable for larger defect reconstruction. With significant comorbidities, however, a primary amputation or other methods must be considered

    Preparation of atom probe tips from (nano)particles in dispersion using (di)electrophoresis and electroplating

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    The behavior of catalytic particles depends on their chemical structure and morphology. To reveal this information, the characterization with atom probe tomography has huge potential. Despite progresses and papers proposing various approaches towards the incorporation of particles inside atom probe tips, no single approach has been broadly applicable to date. In this paper, we introduce a workflow that allowed us to prepare atom probe specimens from Ga particles in suspension in the size range of 50 nm up to 2 μm. By combining dielectrophoresis and electrodeposition in a suitable way, we achieve a near-tip shape geometry, without a time-consuming FIB lift-out. This workflow is a simple and quick method to prepare atom probe tips and allows for a high preparation throughput. Also, not using a lift-out allowed us to use a cryo-stage, avoiding melting of the Ga particles, while ensuring a mechanical stable atom probe tip. The specimen prepared by this workflow enable a stable measurement and low fracture rates. RESEARCH HIGHLIGHTS: Enabling cryo-preparation of (nano)particles for the atom probe. Characterization of surface and bulk elemental distribution of GaPt model SCALMS

    Trendrapport : Vraag naar arbeid 2006

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    Dit OSA Trendrapport Vraag naar Arbeid 2006 peilt hoe het Nederlandse bedrijfsleven in de afgelopen jaren de bakens heeft gezet en verzet op een aantal terreinen zoals omvang en samenstelling van het personeelsbestand, arbeidsvoorwaarden, personeelsbeleid, scholingsactiviteiten, arbeidsomstandigheden, ziekteverzuim, Research & Development. Het geeft ook aan hoe men de eigen toekomst ziet en welke knelpunten men ontwaart. De bevindingen zijn ontleend aan de negende golf van het OSA-Arbeidsvraagpanel die gehouden is in 2005 en het voorjaar van 2006. Deze meting vond dus plaats aan de vooravond van het economisch herstel in Nederland zoals dat vanaf begin 2006 inzette.

    Superlattice growth and rearrangement during evaporation-induced nanoparticle self-assembly

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    Understanding the assembly of nanoparticles into superlattices with well-defined morphology and structure is technologically important but challenging as it requires novel combinations of in-situ methods with suitable spatial and temporal resolution. In this study, we have followed evaporation-induced assembly during drop casting of superparamagnetic, oleate-capped gamma-Fe2O3 nanospheres dispersed in toluene in real time with Grazing Incidence Small Angle X-ray Scattering (GISAXS) in combination with droplet height measurements and direct observation of the dispersion. The scattering data was evaluated with a novel method that yielded time-dependent information of the relative ratio of ordered (coherent) and disordered particles (incoherent scattering intensities), superlattice tilt angles, lattice constants, and lattice constant distributions. We find that the onset of superlattice growth in the drying drop is associated with the movement of a drying front across the surface of the droplet. We couple the rapid formation of large, highly ordered superlattices to the capillary-induced fluid flow. Further evaporation of interstitital solvent results in a slow contraction of the superlattice. The distribution of lattice parameters and tilt angles was significantly larger for superlattices prepared by fast evaporation compared to slow evaporation of the solvent

    Blood volume-monitored regulation of ultrafiltration to decrease the dry weight in fluid-overloaded hemodialysis patients: a randomized controlled trial

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    Abstract Background Because chronic fluid volume overload is associated with higher mortality, we tested whether blood-volume monitored regulation of ultrafiltration and dialysate conductivity (UCR) and/or regulation of ultrafiltration and temperature (UTR) would facilitate dry weight reduction, in comparison to conventional dialysis (CONV). Methods We carried out a multicenter, 4-week, randomized controlled trial in hemodialysis patients ≥15% above normal extracellular fluid volume (ECV), per bioimpedance spectroscopy, who were randomized 1:1:1. Applying UCR (Nikkiso), UTR (Fresenius) and CONV, initial dry weight was reduced rapidly to target. Dry weight reduction was attenuated and eventually stopped at the occurrence of dialysis complications. The primary outcome was defined as intra- and postdialytic complications. Secondary outcomes were magnitudes of dry weight and blood pressure reduction. Results Of 244 patients assessed, N = 95 had volume overload ≥15% above normal ECV. Fifty patients received the allocated interventions (N = 16 UCR, N = 18 UTR, N = 16 CONV) and completed the trial. The rate of complications was significantly lower in UTR compared to CONV (21 ± 21% vs 34 ± 20%, p = 0.022), and also compared to UCR (vs 39 ± 27%, p = 0.028), but not statistically different between UCR and CONV (p = 0.93). Dry weight reduction was significantly higher in UTR compared to UCR (5.0 ± 3.4% vs 2.0 ± 2.7% body weight, p = 0.013), but not compared to CONV (vs 3.9 ± 2.1% body weight, p = 0.31). Systolic blood pressure reduction throughout the intervention phase was 17 ± 22 mmHg overall, but not significantly different between the three groups. Average maximum ultrafiltration rates were significantly higher in UTR than in UCR and CONV, at statistically similar dialysis times. Retrospective examination of randomly selected hemodialysis sessions in the UCR group identified technical mistakes in 36% of the dialysis sessions, despite considerable training efforts. Conclusions Even in patients with volume overload, fluid removal was challenging. Despite the relative advantage of UTR, which must be interpreted with caution in view of the poor technical execution of UCR, this study renders clear that fluid removal must not be reinforced rapidly. Apprehension of this obstacle is imperative for future clinical and academic endeavors aimed at improving dialysis outcomes by correcting volume status. Trial registration ClinicalTrials.gov ( NCT01416753 ), trial registration date: August 12, 2011
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