2,692 research outputs found
Echinococcus multilocularis infection in solid organ transplant recipients
Alveolar echinococcosis (AE) is a zoonosis caused by the ingestion of eggs of the
tapeworm Echinococcus multilocularis, causing a severe infection most often
localized in the liver. Its behavior is similar to that of a malignant tumor as it invades
surrounding tissues and can metastasize to distant organs. If left untreated, the
mortality of AE can be as high as 90% after 10 years. In the immunosuppressed host,
a higher incidence of AE has been reported. Additionally, AE seems to have a faster
evolution, with more severe manifestations. However, there are very few data on the
epidemiology and clinical manifestations of AE specifically in solid-organ transplant
(SOT) recipients.
In this multicentric case series, we retrospectively collected de novo cases of AE in
SOT recipients by searching the STCS database in Switzerland and the FrancEchino
registry in France for cases from 01/2008 to 08/2018. We collected data about the
clinical presentation, diagnosis, treatment and outcome at each center using a
standardized collection form.
A total of 7 patients were identified (kidney=5, heart=1, lung=1), 5 in France and
2 in Switzerland. Six patients presented with liver AE and one with lung AE. AE was
asymptomatic at diagnosis in 4 patients and presented with abdominal pain in 2 of
them. One had undocumented symptoms. The median time between transplantation
and diagnosis was 66 months (ranging from 12 to 240). Two patients had no liver
lesions 26 and 43 months prior to diagnosis, respectively. Diagnosis was done by
serology in all cases (Western-blot was positive in all 7 cases, Em2+ was positive in
1/3, hydatic fluid antigen ELISA in 4/4 and indirect hemagglutination in 3/3).
Imaging was atypical in 2 cases, with a pseudo-tumoral appearance in one case.
Biopsies confirmed AE in 3 cases but led to an erroneous diagnosis in one case. Four
of the 7 patients were operated (all incomplete resections) and 2 died following the
operation. Albendazole was started in all surviving patients and was well tolerated by
all patients (tolerance undocumented in one case). AE remained stable in 3 of the 5
cases and progressed in 1 case. The evolution is undocumented in one case. One
patient died of cause unrelated to AE.
The incidence of AE seems to be higher and its evolution faster in SOT recipients
than in the general population. Our data also suggest that diagnosis of AE in this
population is more challenging, with atypical imaging and sometimes misleading
biopsies. In this series, post-operative mortality was high, perhaps suggesting that a
more conservative approach is needed in this immunocompromised population
Soil radionuclide concentrations and preliminary stormwater model assessment at Material Disposal Area G, Los Alamos National Laboratory
Material Disposal Area G (MDA-G) is at Technical Area (TA) 54 at Los Alamos National Laboratory (LANL). MDA-G has been the principal facility for the disposal of low-level, solid mixed, and transuranic (TRU) waste since 1957, it is currently LANL\u27s primary facility for radioactive solid waste burial and storage. As part of the annual environmental surveillance effort at MDA-G, surface soil samples are collected around the facility\u27s perimeter to characterize possible radionuclide movement off the site through surface water runoff. During 1998, 39 soil samples were collected and analyzed for percent moisture, tritium, plutonium-238 & 239 and americium-241. The results from these samples are compared with baseline or background soil samples collected in an undisturbed area west of the active portion MDA-G to assess radionuclide levels. The 1998 results are also compared to the results from analogous samples collected during 1996 and 97, to assess changes over time in radionuclide activity concentrations in surface soils around the perimeter of MDA-G. The results indicate elevated levels of all the radionuclides assessed in MDA-G surface soils vs the baseline soils. The comparison of 1998 soil data to previous years indicates no significant increase or decrease in radionuclide concentrations; an upward or downward trend in concentrations is not detectable at this time. Continued annual soil sampling will be necessary to realize a trend if one exists. The radionuclide levels found in the perimeter surface soils are significantly above background but still considered relatively low (particularly considering the amount of low-level radioactive waste that has been disposed of at MDA-G over the past 40+ years). The data do indicate that some radioactive material is moving off the site via the surface water runoff/sediment pathway, but in low quantities, which would not be considered a significant risk to human health or the environment. This perimeter surface soil data will be used for planning purposes at MDA-G. Techniques to prevent sediment transport off-site will be implemented in the areas where the highest radionuclide concentrations are indicated
Real-time monitoring of proton exchange membrane fuel cell stack failure
Uneven pressure drops in a 75-cell 9.5-kWe proton exchange membrane fuel cell stack with a U-shaped flow configuration have been shown to cause localised flooding. Condensed water then leads to localised cell heating, resulting in reduced membrane durability. Upon purging of the anode manifold, the resulting mechanical strain on the membrane can lead to the formation of a pin-hole/membrane crack and a rapid decrease in open circuit voltage due to gas crossover. This failure has the potential to cascade to neighbouring cells due to the bipolar plate coupling and the current density heterogeneities arising from the pin-hole/membrane crack. Reintroduction of hydrogen after failure results in cell voltage loss propagating from the pin-hole/membrane crack location due to reactant crossover from the anode to the cathode, given that the anode pressure is higher than the cathode pressure. Through these observations, it is recommended that purging is avoided when the onset of flooding is observed to prevent irreparable damage to the stack
Impact of different SARS-CoV-2 assays on laboratory turnaround time.
Introduction. Clinical microbiology laboratories have had to cope with an increase in the volume of tests due to the emergence of the SARS-CoV-2 virus. Short turnaround times (TATs) are important for case tracing and to help clinicians in patient management. In such a context, high-throughput systems are essential to process the bulk of the tests. Rapid tests are also required to ensure shorter TATs for urgent situations. In our laboratory, SARS-CoV-2 assays were initially implemented on our custom platform using a previously published method. The commercial cobas 6800 (Roche diagnostics) assay and the GeneXpert Xpress (Cepheid) SARS-CoV-2 assay were implemented on 24 March and 8 April 2020, respectively, as soon as available.Hypothesis/Gap Statement. Despite the abundant literature on SARS-CoV-2 assays, the articles focus mainly on the diagnostic performances. This is to our knowledge the first article that specifically studies the TAT of different assays.Aim. We aimed to describe the impact of various SARS-CoV-2 assays on the TAT at the beginning of the outbreak.Methodology. In this study, we retrospectively analysed the TAT of all SARS-CoV-2 assays performed in our centre between 24 February and 9 June, 2020.Results. We retrieved 33 900 analyses, with a median TAT of 6.25 h. TATs were highest (6.9 h) when only our custom platform was used (24 February to 24 March, 2020). They were reduced to 6.1 h when the cobas system was introduced (24 March to 8 April, 2020). The implementation of the GeneXpert further reduced the median TAT to 4.8 h (8 April to 9 June, 2020). The GeneXpert system had the shortest median TAT (1.9 h), followed by the cobas (5.5 h) and by our custom platform (6.9 h).Conclusion. This work shows that the combination of high-throughput systems and rapid tests allows the efficient processing of a large number of tests with a short TAT. In addition, the use of a custom platform allowed the quick implementation of an in-house test when commercial assays were not yet available
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A Biological Signature of Stress Resilience: Immunization with Either Mycobacterium vaccae NCTC 11659 or M. vaccae ATCC 15483 Prevents Stress-induced Changes to Proteomic, Metabolomic, Lipidomic, and Immunological Profiles in Adult Male Rodent Models
A novel deployable radiator system has been designed to reject kilowatt-scale power at afraction of the mass compared to existing technology. The architecture involves a mechanically pumped fluid loop (MPFL) system, inspired by Mars Rover missions, to scale up for the high heat-rejection capabilities that will be necessary as spacecraft become more powerful. The system consists of layered and tapered radiator panels that undergo a similar deployment to rigid solar panels: stowed in a zigzag configuration before flattening straight out. Thin tubes are proposed as structural connectors between panels, acting as deployable hinges as well as thermal-fluid transport tubes. Experiments have characterized the tubes’ bending moment vs angle relationship, and a prototype successfully demonstrated the deployment process using only static pressure from an accumulator which would be sufficient to deploy the tubes in space. A release mechanism for initiating the deployment, using a scrolling sheet released through a burn wire, enables deployment after experiencing launching loads. The single-phase fluid loop system was designed based on existing similar technology, and simplified in order to reduce mass and complexity. The performance of traditional radiator panels is improved by combining advances in materials science with optimal thermal geometry. Instead of aluminum sandwich panels, pyrolytic graphite sheets are used in a tapered configuration to reject 61 W for each 126 g panel when at the layer base temperature of 300 K. Finite element analysis and numerical models are used to determine the effects of layer anisotropy of the design, as well as compute the thermal performance. A single radiator panel was prototyped with the same process and materials as proposed, and the design appears capable of good thermal contact without the need for fasteners. A dynamic analysis was conducted for the 28-panel system for the expected critical modes of vibration resulting in an insufficient natural frequency of 0.02 iii Hz. Through the addition of lightweight hinges and lengthened panels, the system is expected to perform with a fundamental frequency over 0.4 Hz, which is similar to existing deployed panel arrays. Finally, a thermal resistance network was created and solved numerically to determine the heat rejection from a 28-panel pumped-fluid-loop system for a 50 ◦ C spacecraft. Areal density was found to be 1.9 kg/m 2 , or 3.9 kg/m 2 if considering planform area, both considering the total system mass. Heat flux, or rejection per unit radiating area is 205 W/m 2 , or 409 W/m 2 for the planform area. With a weight of 13.3 kg, the system is projected to reject 1400 W of heat, 106 W/kg, a threefold improvement in specific power over similar existing architectures. By incorporating features, developing, and scaling aspects of this design, the next generation of high-power space missions can be realized.</p
How to Resolve an Ethical Dilemma Concerning Randomized Clinical Trials
An apparent ethical dilemma arises when physicians consider enrolling their patients in randomized clinical trials. Suppose that a randomized clinical trial comparing two treatments is in progress, and a physician has an opinion about which treatment is better. The physician has a duty to promote the patient's best medical interests and therefore seems to be obliged to advise the patient to receive the treatment that the physician prefers. This duty creates a barrier to the enrollment of patients in randomized clinical trials.1-10 Two strategies are often used to resolve the dilemma in favor of enrolling patients in clinical trials
The Effects of Fast ForWord Language on the Phonemic Awareness and Reading Skills of School-Age Children With Language Impairments and Poor Reading Skills
Purpose—To examine the efficacy of Fast For-Word Language (FFW-L) and 2 other interventions for improving the phonemic awareness and reading skills of children with specific language impairment with concurrent poor reading skills. Method—A total of 103 children (age 6;0 to 8;11 [years;months]) with language impairment and poor reading skills participated. The children received either FFW-L computerized intervention, a computer-assisted language intervention (CALI), an individualized language intervention (ILI), or an attention control (AC) computer program. Results—The children in the FFW-L, CALI, and ILI conditions made significantly greater gains in blending sounds in words compared with the AC group at immediate posttest. Long-term gains 6 months after treatment were not significant but yielded a medium effect size for blending sounds in words. None of the interventions led to significant changes in reading skills. Conclusion—The improvement in phonemic awareness, but not reading, in the FFW-L, CALI, and ILI interventions limits their use with children who have language impairment and poor reading skills. Similar results across treatment conditions suggest that acoustically modified speech was not a necessary component for improving phonemic awareness
A lung-inspired approach to scalable and robust fuel cell design
A lung-inspired approach is employed to overcome reactant homogeneity issues in polymer electrolyte fuel cells. The fractal geometry of the lung is used as the model to design flow-fields of different branching generations, resulting in uniform reactant distribution across the electrodes and minimum entropy production of the whole system. 3D printed, lung-inspired flow field based PEFCs with N = 4 generations outperform the conventional serpentine flow field designs at 50% and 75% RH, exhibiting a 20% and 30% increase in performance (at current densities higher than 0.8 A cm2) and maximum power density, respectively. In terms of pressure drop, fractal flow-fields with N = 3 and 4 generations demonstrate 75% and 50% lower values than conventional serpentine flow-field design for all RH tested, reducing the power requirements for pressurization and recirculation of the reactants. The positive effect of uniform reactant distribution is pronounced under extended current-hold measurements, where lung-inspired flow field based PEFCs with N = 4 generations exhibit the lowest voltage decay (B5 mV h1). The enhanced fuel cell performance and low pressure drop values of fractal flow field design are preserved at large scale (25 cm2), in which the excessive pressure drop of a large-scale serpentine flow field renders its use prohibitive
Spatial resolution and imaging encoding fMRI settings for optimal cortical and subcortical motor somatotopy in the human brain
There is much controversy about the optimal trade-off between blood-oxygen-level-dependent (BOLD) sensitivity and spatial precision in experiments on brain’s topology properties using functional magnetic resonance imaging (fMRI). The sparse empirical evidence and regional specificity of these interactions pose a practical burden for the choice of imaging protocol parameters. Here, we test in a motor somatotopy experiment the impact of fMRI spatial resolution on differentiation between body part representations in cortex and subcortical structures. Motor somatotopy patterns were obtained in a block-design paradigm and visually cued movements of face, upper and lower limbs at 1.5, 2, and 3 mm spatial resolution. The degree of segregation of the body parts’ spatial representations was estimated using a pattern component model. In cortical areas, we observed the same level of segregation between somatotopy maps across all three resolutions. In subcortical areas the degree of effective similarity between spatial representations was significantly impacted by the image resolution. The 1.5 mm 3D EPI and 3 mm 2D EPI protocols led to higher segregation between motor representations compared to the 2 mm 3D EPI protocol. This finding could not be attributed to differential BOLD sensitivity or delineation of functional areas alone and suggests a crucial role of the image encoding scheme – i.e., 2D vs. 3D EPI. Our study contributes to the field by providing empirical evidence about the impact of acquisition protocols for the delineation of somatotopic areas in cortical and sub-cortical brain regions
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