62 research outputs found

    Structural and optical properties of nanoparticles (V, Al) co-doped ZnO synthesized by sol–gel processes

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    ZnO, Zn0.9V0.1O and Zn0.89V0.1Al0.01O nanoparticles have been prepared by a sol–gel method and their structural and optical properties have been investigated. The obtained nanopowder was characterised by various techniques such as X-ray diffraction (XRD), transmission electron microscopy (TEM) and photoluminescence (PL) spectroscopy. After thermal treatment at 500 C in air, the powder of Zn0.89V0.1Al0.01O with an average particle size of 25 nm presents a strong luminescence band in the visible range. The PL band energy position presents a small blue shift with the increase of measurement temperature. Different possible attributions of this emission band will be discussed

    Digestive Malacoplakia in Children: Case Report

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    Malacoplakia is a form of chronic granulomatous inflammatory reaction that rarely affects the pediatric age group. The gastrointestinal system is the second most common site for the occurrence of malacoplakia. We report the case of a 9-year-old girl who was hospitalized for abdominal pain, chronic diarrhea, and rectal hemorrhage. The endoscopic examinations and histopathology confirmed the diagnosis of intestinal malacoplakia. We successfully treated her with oral levofloxacin. This disease does not have any specific clinical or biological signs, and the diagnosis is exclusively based on histology

    Les Ethmoidites Aigues Exteriorisees De L\'enfant Etude De 11 Observations

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    Les ethmoïdites sont les sinusites les plus fréquentes chez l\'enfant de moins de 3 ans. La gravité de cette affection est liée à l\'extériorisation orbito-oculaire et endocrânienne de l\'infection. But : Analyser les caractéristiques clinico- radiologiques et thérapeutiques de cette affection. Patients et méthodes : Il s\'agit d\'une étude rétrospective portant sur 11 enfants hospitalisés pour ethmoïdite aigue, dans le service de pédiatrie du CHU Farhat Hached de Sousse, durant une période de 6 ans. Résultats : L\'âge moyen de nos patients était de 4 ans et 1/2, ils se répartissaient en 8 filles et 3 garçons. Le délai de consultation était de trois jours en moyenne. La fièvre et l\'oedème palpébral étaient deux critères constants chez tous nos patients. L\'atteinte était unilatérale dans neuf cas, et bilatérale dans deux cas. La TDM éthmoïdo-orbitaire et cérébrale, réalisée pour tous les patients, nous a permis de confirmer le diagnostic et de préciser l\'extension locorégionale. Une cellulite préseptale, une cellulite orbitaire, un abcès sous périosté étaient retrouvées, dans trois cas et une collection orbitaire dans les deux autres. Une bithérapie (céfotaxime-fosfomycine) était prescrite de première intention chez 10 patients. La metronidazole a été associée dans 3 cas Un drainage chirurgical était réalisé chez quatre patients. L\'évolution était favorable dans tous les cas. Conclusion : contenu de la gravité et les germes rencontrés dans cette affection, l\'antibiothérapie de première intention doit être large, précoce et intensive. Le recours au drainage est impératif en cas de collection orbitaire.Acute ethmoiditis are bacterial infections of ethmoid sinuses, which may spread to the orbital or the endocranial spaces.They are the most frequent among bacterial sinusitis before 3 years. Population and methods:Our study is retrospective, it included all children hospitalized in our pediatric unit from 2000 to 2006 for an acute ethmoiditis. We analyzed clinical and radiological presentations, and discussed therapeutic modalities used to treat this pathology. Results:Over this 6-years period, 11 children (mean age 4.5 years) where hospitalized for acute ethmoïdites.They were 3 boy and 8 girls. All patients presented with high fever and palpabral oedems. Etmoïditis was unilateral in 9 Children and bilateral in two. Ethmoïdio-orbital CT scan confirmed acute ethmoïdis, the cerebral one assessed intra-cranial diffusion. The acute ethmoidis was complicated with, preseptal cellulites in three cases, orbital cellulitis in three cases, subperiostal abscess in three others and orbital collection in two patients. Most children received an association of cefotaxisme and fosfomycemie for a mean duration of 13 days. Metronidazole was associated to the previous antibiotherapy in three cases. Four patients, required surgical treatment in addition to antibiotherapy.All children saw favorable out come. Conclusion:It is always difficult to found the bacteria responsible for an acute ethmoiditis. The first antibiotic therapy must be chosen to be effective in the most frequently responsible bacteria tacking in consideration the potentiel severity of this sinusitis. Journal Tunisien d\'ORL et de chirurgie cervico-faciale Vol. 16 2006: pp. 22-2

    A Robust Approach for Multivariate Binary Vectors Clustering and Feature Selection

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    International audienceGiven a set of binary vectors drawn from a ¯nite multiple Bernoulli mixture model, an important problem is to determine which vectors are outliers and which features are relevant. The goal of this paper is to propose a model for binary vectors clustering that accommo- dates outliers and allows simultaneously the incorporation of a feature selection methodology into the clustering process. We derive an EM al- gorithm to ¯t the proposed model. Through simulation studies and a set of experiments involving handwritten digit recognition and visual scenes categorization, we demonstrate the usefulness and e®ectiveness of our method

    Dirichlet Multinomial Mixtures: Generative Models for Microbial Metagenomics

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    We introduce Dirichlet multinomial mixtures (DMM) for the probabilistic modelling of microbial metagenomics data. This data can be represented as a frequency matrix giving the number of times each taxa is observed in each sample. The samples have different size, and the matrix is sparse, as communities are diverse and skewed to rare taxa. Most methods used previously to classify or cluster samples have ignored these features. We describe each community by a vector of taxa probabilities. These vectors are generated from one of a finite number of Dirichlet mixture components each with different hyperparameters. Observed samples are generated through multinomial sampling. The mixture components cluster communities into distinct ‘metacommunities’, and, hence, determine envirotypes or enterotypes, groups of communities with a similar composition. The model can also deduce the impact of a treatment and be used for classification. We wrote software for the fitting of DMM models using the ‘evidence framework’ (http://code.google.com/p/microbedmm/). This includes the Laplace approximation of the model evidence. We applied the DMM model to human gut microbe genera frequencies from Obese and Lean twins. From the model evidence four clusters fit this data best. Two clusters were dominated by Bacteroides and were homogenous; two had a more variable community composition. We could not find a significant impact of body mass on community structure. However, Obese twins were more likely to derive from the high variance clusters. We propose that obesity is not associated with a distinct microbiota but increases the chance that an individual derives from a disturbed enterotype. This is an example of the ‘Anna Karenina principle (AKP)’ applied to microbial communities: disturbed states having many more configurations than undisturbed. We verify this by showing that in a study of inflammatory bowel disease (IBD) phenotypes, ileal Crohn's disease (ICD) is associated with a more variable community

    Potential utility of hyperbaric oxygen therapy and propolis in enhancing the leishmanicidal activity of glucantime

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    In this study we investigated the efficacy of hyperbaric oxygen (HBO) therapy, alone or combined with the pentavalent antimonial glucantime on Leishmania amazonensis infection. In parallel, the effect of Brazilian red propolis gel (propain) alone or combined with glucantime on L. amazonensis infection was evaluated. The inhibition of the infection in macrophages treated with glucantime in combination with HBO exposition was greater than that of macrophages treated with glucantime alone or HBO alone. The susceptible mouse strain BALB/c infected in the shaved rump with L. amazonensis treated with glucantime and exposed to HBO showed: time points in the course of the disease in which lesions were smaller than those of mice treated with glucantime alone and revascularization of the skin in the lesion site; interferon-gamma (IFN-g) levels were not elevated in lymph node cells from these animals. Propain alone was not efficient against lesions, although less exudative lesions were observed in animals treated with propain alone or combined with glucantime. These results reveal the potential value of HBO and red propolis in combination with glucantime for treating cutaneous leishmaniasis and encourage further studies on the effect of more aggressive HBO, propolis and glucantime therapies on different mouse models of leishmaniasis

    Global Retinoblastoma Presentation and Analysis by National Income Level

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    Importance: Early diagnosis of retinoblastoma, the most common intraocular cancer, can save both a child's life and vision. However, anecdotal evidence suggests that many children across the world are diagnosed late. To our knowledge, the clinical presentation of retinoblastoma has never been assessed on a global scale. Objectives: To report the retinoblastoma stage at diagnosis in patients across the world during a single year, to investigate associations between clinical variables and national income level, and to investigate risk factors for advanced disease at diagnosis. Design, Setting, and Participants: A total of 278 retinoblastoma treatment centers were recruited from June 2017 through December 2018 to participate in a cross-sectional analysis of treatment-naive patients with retinoblastoma who were diagnosed in 2017. Main Outcomes and Measures: Age at presentation, proportion of familial history of retinoblastoma, and tumor stage and metastasis. Results: The cohort included 4351 new patients from 153 countries; the median age at diagnosis was 30.5 (interquartile range, 18.3-45.9) months, and 1976 patients (45.4%) were female. Most patients (n = 3685 [84.7%]) were from low- A nd middle-income countries (LMICs). Globally, the most common indication for referral was leukocoria (n = 2638 [62.8%]), followed by strabismus (n = 429 [10.2%]) and proptosis (n = 309 [7.4%]). Patients from high-income countries (HICs) were diagnosed at a median age of 14.1 months, with 656 of 666 (98.5%) patients having intraocular retinoblastoma and 2 (0.3%) having metastasis. Patients from low-income countries were diagnosed at a median age of 30.5 months, with 256 of 521 (49.1%) having extraocular retinoblastoma and 94 of 498 (18.9%) having metastasis. Lower national income level was associated with older presentation age, higher proportion of locally advanced disease and distant metastasis, and smaller proportion of familial history of retinoblastoma. Advanced disease at diagnosis was more common in LMICs even after adjusting for age (odds ratio for low-income countries vs upper-middle-income countries and HICs, 17.92 [95% CI, 12.94-24.80], and for lower-middle-income countries vs upper-middle-income countries and HICs, 5.74 [95% CI, 4.30-7.68]). Conclusions and Relevance: This study is estimated to have included more than half of all new retinoblastoma cases worldwide in 2017. Children from LMICs, where the main global retinoblastoma burden lies, presented at an older age with more advanced disease and demonstrated a smaller proportion of familial history of retinoblastoma, likely because many do not reach a childbearing age. Given that retinoblastoma is curable, these data are concerning and mandate intervention at national and international levels. Further studies are needed to investigate factors, other than age at presentation, that may be associated with advanced disease in LMICs

    Classification of Caesarean Section and Normal Vaginal Deliveries Using Foetal Heart Rate Signals and Advanced Machine Learning Algorithms

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    ABSTRACT – Background: Visual inspection of Cardiotocography traces by obstetricians and midwives is the gold standard for monitoring the wellbeing of the foetus during antenatal care. However, inter- and intra-observer variability is high with only a 30% positive predictive value for the classification of pathological outcomes. This has a significant negative impact on the perinatal foetus and often results in cardio-pulmonary arrest, brain and vital organ damage, cerebral palsy, hearing, visual and cognitive defects and in severe cases, death. This paper shows that using machine learning and foetal heart rate signals provides direct information about the foetal state and helps to filter the subjective opinions of medical practitioners when used as a decision support tool. The primary aim is to provide a proof-of-concept that demonstrates how machine learning can be used to objectively determine when medical intervention, such as caesarean section, is required and help avoid preventable perinatal deaths. Methodology: This is evidenced using an open dataset that comprises 506 controls (normal virginal deliveries) and 46 cases (caesarean due to pH ≤7.05 and pathological risk). Several machine-learning algorithms are trained, and validated, using binary classifier performance measures. Results: The findings show that deep learning classification achieves Sensitivity = 94%, Specificity = 91%, Area under the Curve = 99%, F-Score = 100%, and Mean Square Error = 1%. Conclusions: The results demonstrate that machine learning significantly improves the efficiency for the detection of caesarean section and normal vaginal deliveries using foetal heart rate signals compared with obstetrician and midwife predictions and systems reported in previous studies

    Travel burden and clinical presentation of retinoblastoma: analysis of 1024 patients from 43 African countries and 518 patients from 40 European countries

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    BACKGROUND: The travel distance from home to a treatment centre, which may impact the stage at diagnosis, has not been investigated for retinoblastoma, the most common childhood eye cancer. We aimed to investigate the travel burden and its impact on clinical presentation in a large sample of patients with retinoblastoma from Africa and Europe. METHODS: A cross-sectional analysis including 518 treatment-naïve patients with retinoblastoma residing in 40 European countries and 1024 treatment-naïve patients with retinoblastoma residing in 43 African countries. RESULTS: Capture rate was 42.2% of expected patients from Africa and 108.8% from Europe. African patients were older (95% CI -12.4 to -5.4, p<0.001), had fewer cases of familial retinoblastoma (95% CI 2.0 to 5.3, p<0.001) and presented with more advanced disease (95% CI 6.0 to 9.8, p<0.001); 43.4% and 15.4% of Africans had extraocular retinoblastoma and distant metastasis at the time of diagnosis, respectively, compared to 2.9% and 1.0% of the Europeans. To reach a retinoblastoma centre, European patients travelled 421.8 km compared to Africans who travelled 185.7 km (p<0.001). On regression analysis, lower-national income level, African residence and older age (p<0.001), but not travel distance (p=0.19), were risk factors for advanced disease. CONCLUSIONS: Fewer than half the expected number of patients with retinoblastoma presented to African referral centres in 2017, suggesting poor awareness or other barriers to access. Despite the relatively shorter distance travelled by African patients, they presented with later-stage disease. Health education about retinoblastoma is needed for carers and health workers in Africa in order to increase capture rate and promote early referral
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