322 research outputs found
Airway stenting with the LT-Mold? for severe glotto-subglottic stenosis or intractable aspiration: experience in 65 cases.
The purpose of this study was to assess the safety and efficacy of stenting in upper airway reconstructions for benign laryngotracheal stenosis (LTS) with a newly designed prosthesis, the LT-Mold?. The LT-Mold and its proper use during open surgery and endoscopy are described, and the experience gathered from a prospectively collected database on 65 patients treated for complex LTS or severe aspiration is reported. This series is compared to the results of other stenting methods. All patients were available for evaluation. In all but one case, the prosthesis was removed at the end of the study. The new prosthesis did not induce any stent-related trauma to the supraglottis, glottis and subglottis. Before adding a distal round-shaped silicone cap to the LT-Mold, granulation tissue was usually seen at the stent-mucosal interface at the tracheostoma level. In 14 cases, there has been a spontaneous extrusion of the prosthesis through the mouth; this problem was solved by fixing the prosthesis through the reinforced portion of the prosthesis at the cap level and by adding one fixation stitch in the supraglottis. We have to document the loss of the silicone cap in three cases. This problem was resolved by designing a new prototype with an integrated cap, glued with a slow hardening silicone glue. Fifty-four (83Ā %) of 65 patients were decannulated after a mean duration of stenting of 3Ā months (range 1-12Ā months). The mean follow-up after decannulation was 23Ā months (range 1Ā month to 10Ā years). The experience gathered with the LT-Mold shows that long-term stenting for complex LTS is safely achieved when the prosthesis is used with its distal integrated silicone cap. The softness and smoothness of the prosthesis with a round-shaped configuration of both extremities help avoid ulceration and granulation tissue formation in the reconstructed airway. Adequate fixation is mandatory to avoid extrusion
Detection of Sex-Related Differential Item Functioning in Ravenās Standard Progressive Matrices Test Using the Mantel-Haenszel Method
This study aimed to determine the presence of sex-related differential item functioning (DIF) in Ravenās Standard Progressive Matrices (SPM) Test. The research design was a comparative study, where boys formed the focal group and girls formed the reference group. The software used was SPSS-v26, and binary data of focal and reference groups were analyzed using jMetrik software to detect DIF according to the Mantel-Haenszel method. A total of 1032 students (49.6% boys and 50.4% girls), 570 from intermediate school and 462 from secondary school, were selected from 24 schools using a stratified random-sampling procedure. The statistical analyses showed that the Ravenās Standard Progressive Matrices (SPM) Test was one-dimensional. The results showed that, of five moderate DIF items, four items favored the focal group (boys), and one item favored the reference group (girls). The results also showed two large DIF items; the direction of the one item favored the reference group (girls), and the direction of the second item favor the focal group (boys). The findings showed that there were several unbiased items, but some were clearly biased against female performance. According to these findings, we recommend reanalyzing the data using methods depending on the item response theory, such as the logistic regression, simultaneous item bias test (SIB) or IRT-likelihood ratio (IRT-LR) methods to confirm the results seen here. Keywords: Differential Item Functioning (DIF), Bias Item, Reference Group, Focal Group DOI: 10.7176/JEP/11-29-10 Publication date:October 31st 202
Magnetic and Optical properties of strained films of multiferroic GdMnO3
The effects of strain on a film of mulitferroic GdMnO3 are investigated using
both magnetometry and magneto-optic spectroscopy. Optical spectra, in the
energy range 1.5eV - 3.5eV, were taken in Faraday geometry in an applied
magnetic field and also at remanence. This yielded rich information on the
effects of strain on the spin ordering in these films. Epitaxial films of
GdMnO3 were grown on SrTiO3 and LaAlO3 substrates. The LaAlO3 was twinned and
so produced a highly strained film whereas the strain was less for the film
grown on SrTiO3. The Ne\'el temperatures and coercive fields were measured
using zero field data and hysteresis loops obtained using a SQUID magnetometer.
Optical absorption data agreed with earlier work on bulk materials. The two
well known features in the optical spectrum, the charge transfer transition
between Mn d states at ~2eV and the band edge transition from the oxygen p band
to the d states at ~3eV are observed in the magnetic circular dichroism;
however they behaved very differently both as a function of magnetic field and
temperature. This is interpreted in terms of the magnetic ordering of the Mn
spins.Comment: 9 pages of text including figure
On Using Magnetic and optical methods to determine the size and characteristics of nanoparticles embedded in oxide semiconductors
Films of oxides doped with transition metals are frequently believed to have
magnetic inclusions. Magnetic methods to determine the amount of nanophases and
their magnetic characteristics are described. The amount of the sample that is
paramagnetic may also be measured. Optical methods are described and shown to
be very powerful to determine which defects are also magnetic.Comment: Manuscript of poster to be presented at MMM-Intermag 2010. Accepted
for publication in Magnetic Trans of IEE
A switching multi-level method for the long tail recommendation problem
Recommender systems are decision support systems that play an important part in generating a list of product or service recommendations for users based on the past experiences and interactions. The most popular recommendation method is Collaborative Filtering (CF) that is based on the usersā rating history to generate the recommendation. Although, recommender systems have been applied successfully in different areas such as e-Commerce and Social Networks, the popularity bias is still one of the challenges that needs to be further researched. Therefore, we propose a multi-level method that is based on a switching approach which solves the long tail recommendation problem (LTRP) when CF fails to find the target case. We have evaluated our method using two public datasets and the results show that it outperforms a number of bases lines and state-of-the-art alternatives with a further reduce of the recommendation error rates for items found in the long tail
The Prescriptionsā Epidemiology of the Challenges for Overcoming Antibiotic Resistance in Hospitals
Understanding the mechanisms of antibiotic resistance is important in the development of strategies to solving the problem. Active efflux of drugs, alteration of target sites and enzymatic degradations are the strategies by which pathogenic bacteria acquire or develop intrinsic resistance to antibiotics. Multi-drug resistance (MDR) pumps, capable of recognizing and expelling a variety of structurally unrelated compounds from the bacterial cell and conferring resistance to a wide range of antibiotics have since been characterized in many gram positive and gram negative pathogens like Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli and, more recently, in mycobacteria. The ability of some chemical compounds to modify the resistance phenotype in bacteria by working synergistically with antibiotics in vitro has since been observed. The search for such compounds which can be combined with antibiotics in the treatment of drug resistant infections may be an alternative to overcoming the problem of resistance in bacteria. Keywords: Antibiotic resistance, resistance modifying agents
Genetic deletion of fibroblast growth factor 14 recapitulates phenotypic alterations underlying cognitive impairment associated with schizophrenia
Cognitive processing is highly dependent on the functional integrity of gamma-amino-butyric acid (GABA) interneurons in the brain. These cells regulate excitability and synaptic plasticity of principal neurons balancing the excitatory/inhibitory tone of cortical networks. Reduced function of parvalbumin (PV) interneurons and disruption of GABAergic synapses in the cortical circuitry result in desynchronized network activity associated with cognitive impairment across many psychiatric disorders, including schizophrenia. However, the mechanisms underlying these complex phenotypes are still poorly understood. Here we show that in animal models, genetic deletion of fibroblast growth factor 14 (Fgf14), a regulator of neuronal excitability and synaptic transmission, leads to loss of PV interneurons in the CA1 hippocampal region, a critical area for cognitive function. Strikingly, this cellular phenotype associates with decreased expression of glutamic acid decarboxylase 67 (GAD67) and vesicular GABA transporter (VGAT) and also coincides with disrupted CA1 inhibitory circuitry, reduced in vivo gamma frequency oscillations and impaired working memory. Bioinformatics analysis of schizophrenia transcriptomics revealed functional co-clustering of FGF14 and genes enriched within the GABAergic pathway along with correlatively decreased expression of FGF14, PVALB, GAD67 and VGAT in the disease context. These results indicate that Fgf14(-/-) mice recapitulate salient molecular, cellular, functional and behavioral features associated with human cognitive impairment, and FGF14 loss of function might be associated with the biology of complex brain disorders such as schizophrenia
Magneto-optical properties of Co/ZnO multilayer films
Multilayer films of ZnO with Co were deposited on glass substrates then
annealed in a vacuum. The magnetisation of the films increased with annealing
but not the magnitude of the magneto-optical signals. The dielectric functions
for the films were calculated using the MCD spectra. A Maxwell Garnett theory
of a metallic Co/ZnO mixture is presented. The extent to which this explains
the MCD spectra taken on the films is discussed.Comment: This paper was presented at ICM (2009) and is accepted in this form
for the proceeding
A Systemic Review of Iron Deficiency Anemia in Adults and the Clinical Management of Diagnosis and Treatment
Iron deficiency is the most frequent cause of anaemia worldwide. It impairs quality of life, increases asthenia and can lead to clinical worsening of patients. In addition, iron deficiency has a complex mechanism whose pathologic pathway is recently becoming better understood. The discovery of hepcidin has allowed a better clarification of iron metabolism regulation. Furthermore, the ratio of concentration of soluble transferrin receptor to the log of the ferritin level, has been developed as a tool to detect iron deficiency in most situations. Therefore, the problem of this research lies in exploring the cause of iron deficiency that always be sought because the underlying condition can be serious. This review will summarize the current knowledge regarding diagnostic algorithms for iron deficiency anemia. The majority of aetiologies occur in the digestive tract, and justify morphological examination of the gut. First line investigations are upper gastrointestinal endoscopy and colonoscopy, and when negative, the small bowel should be explored; newer tools such as video capsule endoscopy have also been developed. The treatment of iron deficiency is aetiological if possible and iron supplementation whether in oral or in parenteral form
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