3,036 research outputs found
Ileal Mucosal and Fecal Pancreatitis Associated Protein Levels Reflect Severity of Salmonella Inflection in Rats
Background Microbial infections induce ileal pancreatitis-associated protein/regenerating gene III (PAP/RegIII) mRNA expression. Despite increasing interest, little is known about the PAP/RegIII protein. Therefore, ileal mucosal PAP/RegIII protein expression, localization, and fecal excretion were studied in rats upon Salmonella infection. Results Salmonella infection increased ileal mucosal PAP/RegIII protein levels in enterocytes located at the crypt-villus junction. Increased colonization and translocation of Salmonella was associated with higher ileal mucosal PAP/RegIII levels and secretion of this protein in feces. Conclusions PAP/RegIII protein is increased in enterocytes of the ileal mucosa during Salmonella infection and is associated with infection severity. PAP/RegIII is excreted in feces and might be used as a new and non-invasive infection marke
Searching for order in atmospheric pressure plasma jets
The self-organized discharge behaviour occurring in a non-thermal radio-frequency plasma jet in rare gases at atmospheric pressure was investigated. The frequency of the azimuthal rotation of filaments in the active plasma volume and their inclination were measured along with the gas temperature under varying discharge conditions. The gas flow and heating were described theoretically by a three-dimensional hydrodynamic model. The rotation frequencies obtained by both methods qualitatively agree. The results demonstrate that the plasma filaments forming an inclination angle α with the axial gas velocity u z are forced to a transversal movement with the velocity , which is oriented in the inclination direction. Variations of in the model reveal that the observed dynamics minimizes the energy loss due to convective heat transfer by the gas flow. The control of the self-organization regime motivates the application of the plasma jet for precise and reproducible material processing
Feasibility of plasma treated clay in clay/polymer nanocomposites powders for use Laser Sintering (LS)
The addition of small quantities of nano-clay to nylon is known to improve mechanical properties of the resulting nano-composite. However, achieving a uniform dispersion and distribution of the clay within the base polymer can prove difficult. A demonstration of the fabrication and characterization of plasma-treated organoclay/Nylon12 nanocomposite was carried out with the aim of achieving better dispersion of clay platelets on the Nylon12 particle surface. Air-plasma etching was used to enhance the compatibility between clays and polymers to ensure a uniform clay dispersion in composite powders. Downward heat sintering (DHS) in a hot press is used to process neat and composite powders into tensile and XRD specimens. Morphological studies using Low Voltage Scanning Electron Microscopy (LV-SEM) were undertaken to characterize the fracture surfaces and clay dispersion in powders and final composite specimens. Thermogravimetric analysis (TGA) testing performed that the etched clay (EC) is more stable than the nonetched clay (NEC), even at higher temperatures. The influence of the clay ratio and the clay plasma treatment process on the mechanical properties of the nano-composites was studied by tensile testing. The composite fabricated from (3% EC/N12) powder showed ~19 % improvement in elastic modulus while the composite made from (3% NEC/N12) powder was improved by only 14%). Most notably however is that the variation between tests is strongly reduced when etch clay is used in the composite. We attribute this to a more uniform distribution and better dispersion of the plasma treated clay within polymer powders and ultimately the composite
Quantitative secondary electron imaging for work function extraction at atomic level and layer identification of graphene
Two-dimensional (2D) materials usually have a layer-dependent work function, which require fast
and accurate detection for the evaluation of their device performance. A detection technique with
high throughput and high spatial resolution has not yet been explored. Using a scanning electron
microscope, we have developed and implemented a quantitative analytical technique which allows
effective extraction of the work function of graphene. This technique uses the secondary electron
contrast and has nanometre-resolved layer information. The measurement of few-layer graphene flakes
shows the variation of work function between graphene layers with a precision of less than 10meV. It is
expected that this technique will prove extremely useful for researchers in a broad range of fields due to
its revolutionary throughput and accuracy
Evolutionary determination of experimental parameters for ptychographical imaging
The Ptychographical Iterative Engine (PIE) algorithm is a recently developed novel method of Coherent Diffractive Imaging (CDI) that uses multiple overlapping diffraction patterns to reconstruct an image. This method has successfully produced high quality reconstructions at both optical and X-ray wavelengths but the need for accurate knowledge of the probe positions is currently a limiting factor in the production of high resolution reconstructions at electron wavelengths. This paper examines the shape of the search landscape for producing optimal image reconstructions in the specific case of electron microscopy and then shows how evolutionary search methods can be used to reliably determine experimental parameters in the electron microscopy case (such as the spherical aberration in the probe and the probe positions)
Repeated audiometry after bacterial meningitis: Consequences for future management
Objective: Sensorineural hearing loss is a common sequela of bacterial meningitis. The objective of this study is to delineate the incidence and course of hearing loss after bacterial meningitis. Study Design: Retrospective cohort study. Setting: Tertiary referral center. Patients: Data of 655 patients who suffered from bacterial meningitis between 1985 and 2015 were analyzed. Interventions: None. Main Outcome Measurements: Availability of audiometric data, incidence of hearing loss, and onset and course of hearing loss. Results: In this cohort the incidence of hearing loss (>25 dB) was 28% (95% confidence interval 23-34%). The incidence of profound hearing loss (>80 dB) was 13% (95% confidence interval 10-18%). Normal hearing at the first assessment after treatment for meningitis remained stable over time in all these patients. In 19 of the 28 patients with diagnosed hearing loss, the hearing level remained stable over time. Hearing improved in six patients and deteriorated in two patients. One patient showed a fluctuating unilateral hearing loss. Conclusion: Audiological tests in patients with bacterial meningitis, especially children, should be started as soon as possible after the acute phase is over. As we found no deterioration of initial normal hearing after bacterial meningitis, repeated audiometry seems indicated only for those with diagnosed hearing loss at first assessment
Occurrence of epidermal growth factor receptors in benign and malignant ovarian tumors and normal ovarian tissues: an immunohistochemical study
Epidermal growth factor receptor (EGF-R) was studied with monoclonal antibody 2E9 on 50 ovarian tumors of various histological types and 10 non-tumorous ovarian tissues by immunohistochemistry. Enhanced expression was observed in 26/50 (52%) of the tumors. Only 25 out of 46 epithelial tumors (54%) showed positivity in epithelial tumor cells. Staining was cytoplasmic in all cases. No correlation was established between EGF-R expression and the histological type of the epithelial tumor. Apart from EGF-R expression in tumor cells, low immunoreactivity was also observed in stromal and endothelial cells in both normal and tumorous ovarian tissues. Furthermore in 8/9 specimens containing necrotic areas, EGF-R was noticed in these areas as well. Both of the latter observations may have impact on the evaluation of the prognostic value of EGF-R activity in tumors, when based on EGF-R measurements using biochemical binding studies. We therefore recommend that EGF-R is measured with both methods in studies regarding its clinical value
Nanoscale Mapping of Bromide Segregation on the Cross Sections of 2 Complex Hybrid Perovskite Photovoltaic Films Using Secondary 3 Electron Hyperspectral Imaging in a Scanning Electron Microscope
Mixed halide (I/Br) complex organic/inorganic hybrid perovskite materials have attracted much attention recently because of their excellent photovoltaic properties. Although it has been proposed that their stability is linked to the chemical inhomogeneity of I/Br, no direct proof has been offered to date. Here, we report a new method, secondary electron hyperspectral imaging (SEHI), which allows direct imaging of the local variation in Br concentration in mixed halide (I/Br) organic/inorganic hybrid perovskites on a nanometric scale. We confirm the presence of a nonuniform Br distribution with variation in concentration within the grain interiors and boundaries and demonstrate how SEHI in conjunction with low-voltage scanning electron microscopy can enhance the understanding of the fundamental physics and materials science of organic/inorganic hybrid photovoltaics, illustrating its potential for research and development in “real-world” applications
Predicting homeless people’s perceived health after entering the social relief system in The Netherlands
Objectives: We explored whether changes in the perceived health of homeless people after entering the social relief system (SRS) in The Netherlands were predicted by housing, income, hours of work, social support, unmet care needs, arrests, physical and mental health, substance use, and experiences of autonomy, competence and relatedness, in addition to perceived health at baseline, demographics, suspected intellectual disability, the duration of homelessness and the company of children in the shelter facility. Methods: A hierarchical regression analysis was used to explore the significant predictors of the perceived health of 344 homeless persons 18 months after entering the social relief system. Results: A decrease in psychological distress and an increase in hours of (paid/voluntary) work as well as competence predicted a better perceived health. Conclusions: Perceived health is not only influenced by objective circumstances related to work and mental health, but also self-determination, as shown by the influence of competence. Services should aim to reduce psychological distress of homeless people, support them in increasing their working hours and focus on strengthening their competence
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