222 research outputs found

    Finite Sample FPE and AIC Criteria for Autoregressive Model Order Selection Using Same-Realization Predictions

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    A new theoretical approximation for expectation of the prediction error is derived using the same-realization predictions. This approximation is derived for the case that the Least-Squares-Forward (LSF) method (the covariance method) is used for estimating the parameters of the autoregressive (AR) model. This result is used for obtaining modified versions of the AR order selection criteria FPE and AIC in the finite sample case. The performance of these modified criteria is compared with other same-realization AR order selection criteria using simulated data. The results of this comparison show that the proposed criteria have better performance

    Frequency of Self-Medication and Knowledge about Out-of-Counter Drugs during the COVID-19 Pandemic in a Group of Iranian Dental Students

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    Objective: To study the frequency of self-medication and knowledge about out-of-counter drugs during the COVID-19 pandemic in a group of Iranian dental students. Material and Methods: A descriptive cross-sectional study was conducted among dental undergraduates from September 2021 to November 2021 after receiving ethical clearance from the Kerman Medical University Ethical Committee. A valid and reliable questionnaire, consisting of demographic data and questions about self-medication and knowledge about out-of-counter drugs, was sent to participants via E-mail. Data was analyzed by SPSS 26 software by using a t-test. The P-value was considered at a 0.05% significant level. Results: A total of 88 students participated in the study with a mean age of 21.39±3.71 years. Prevalence of self-medication was found in 53.4%. The most common cause for self-medication was headache. Acetaminophen was the most commonly used medicine for self-medication. Females had more self-medication than males, but there was no significant differences. There was no significant differences between entering year to university and self-medication. Younger students had significantly more self-medication (p=0.007). Knowledge about out-of-counter drugs was moderate. Conclusion: Moderate self-medication as noticed. The out-of-counter drugs were the most used. Although out-of-counter drugs seem relatively safe, their improper use can cause serious side effects. Dental students need to be educated regarding appropriate safe medication and out-of-counter drugs

    Concomitant dislocation of the tarsometatarsal and metatarsophalangeal joints of the second toe (floating second metatarsal): a case report

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    When examining patients with injuries of the tarsometatarsal joint, the physician must pay attention to the foot as a whole

    Sealing ability of three temporary filling materials in endodontically-treated teeth

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    INTRODUCTION: Coronal microleakage may significantly reduce the prognosis of endodontic treatment. Temporary restorative materials have a crucial role in preventing the infection of root canals between and after endodontic treatment. This in vitro study was designed to evaluate the coronal microleakage of three temporary restorative materials used in endodontics: Coltosol, Cavisol and Cina. MATERIALS AND METHODS: Seventy-five human premolars and molars were selected for this in vitro study. Access cavities were prepared and amalgam placed on the orifices of canals; the occlusal surfaces were then reduced by 4mm for the temporary restoration. The teeth were divided into three experimental groups of 23 teeth and two control groups of 3 teeth. The access cavities in each group were sealed using one of the test materials and thermal cycling was applied (5-55ÂșC for 150 cycles). Surfaces were then covered with nail polish and wax; the teeth were immersed in 2% methylene blue dye for 7 days. The teeth were rinsed, dried, and sectioned mesiodistally and evaluated under a stereomicroscope for microleakage. Data was analyzed using Kruskal-Wallis and Mann U Whitney tests. RESULTS: The lowest microleakage value was observed in Cavisol and Coltosol groups and the highest in Cina group (P<0.001). There was no statistical difference between Cavisol and Coltosol. CONCLUSION: Coltosol and Cavisol have appropriate sealing properties as temporary restorations, but the sealing ability of Cina was questionable

    Therapeutic Possibilities of Ceftazidime Nanoparticles in Devastating Pseudomonas Ophthalmic Infections; Keratitis and Endophthalmitis

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    As the number of contact‐lens wearers rises worldwide, Pseudomonas aeruginosa (PA) keratitis is attracting more attention as a major public health issue. Corneal lesions of PA, being the most intimidating complication of contact‐lens wearer, can progress rapidly in spite of local antibiotic treatment, and may result in perforation and the permanent loss of vision. One of the explanations proposed for the evasion of the pathogen from immune responses of the host as well as antibacterial treatment is the fact that invasive clinical isolates of PA have the unusual ability to invade and replicate within surface corneal epithelial cells. In this manner, PA is left with an intracellular sanctuary. Endophthalmitis, albeit rare, is another ophthalmic infection faced by the challenge of drug delivery that can be potentially catastrophic. The present hypothesis is that nanoparticles can carry anti‐pseudomonas antibiotics (e.g. ceftazidime) through the membranes, into the “hidden zone” of the pathogen, hence being an effective and potent therapeutic approach against pseudomonas keratitis and endophthalmitis

    Genome-wide gene expression profiling of stress response in a spinal cord clip compression injury model.

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    BackgroundThe aneurysm clip impact-compression model of spinal cord injury (SCI) is a standard injury model in animals that closely mimics the primary mechanism of most human injuries: acute impact and persisting compression. Its histo-pathological and behavioural outcomes are extensively similar to human SCI. To understand the distinct molecular events underlying this injury model we analyzed global mRNA abundance changes during the acute, subacute and chronic stages of a moderate to severe injury to the rat spinal cord.ResultsTime-series expression analyses resulted in clustering of the majority of deregulated transcripts into eight statistically significant expression profiles. Systematic application of Gene Ontology (GO) enrichment pathway analysis allowed inference of biological processes participating in SCI pathology. Temporal analysis identified events specific to and common between acute, subacute and chronic time-points. Processes common to all phases of injury include blood coagulation, cellular extravasation, leukocyte cell-cell adhesion, the integrin-mediated signaling pathway, cytokine production and secretion, neutrophil chemotaxis, phagocytosis, response to hypoxia and reactive oxygen species, angiogenesis, apoptosis, inflammatory processes and ossification. Importantly, various elements of adaptive and induced innate immune responses span, not only the acute and subacute phases, but also persist throughout the chronic phase of SCI. Induced innate responses, such as Toll-like receptor signaling, are more active during the acute phase but persist throughout the chronic phase. However, adaptive immune response processes such as B and T cell activation, proliferation, and migration, T cell differentiation, B and T cell receptor-mediated signaling, and B cell- and immunoglobulin-mediated immune response become more significant during the chronic phase.ConclusionsThis analysis showed that, surprisingly, the diverse series of molecular events that occur in the acute and subacute stages persist into the chronic stage of SCI. The strong agreement between our results and previous findings suggest that our analytical approach will be useful in revealing other biological processes and genes contributing to SCI pathology

    Application of SPACE Matrix

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    One of the most important questions for concrete construction firms managers is that what the current status of their concrete construction firm is. This paper presents the application of strategic position and action evaluation matrix (Space Analysis) to find the answer of this question for a concrete construction the best degree of strategy managing to execute four strategies against the rivals, namely aggressive, conservative, defensive and competitive strategies. Value of each factor mentioned in this matrix, were earned by preparing questionnaire surveys. These factors were listed in four groups (Financial Strength, Industry Attractiveness, Environmental Stability and Competitive Advantage) to identify which kind of strategy should be used by this firm. Key words: Strategy ,Space Analysis, aggressive, conservative, defensive and competitive strategies

    Photocatalytic valorization of biobased alcoholic wastes: a sustainable approach for the generation of green products

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    Ces derniĂšres annĂ©es, une attention croissante a Ă©tĂ© portĂ©e Ă  la valorisation de diffĂ©rents types de rĂ©sidus en produits chimiques Ă  valeur ajoutĂ©e. La valorisation des rĂ©sidus peut non seulement rĂ©soudre les problĂšmes environnementaux croissants et actuels, mais elle peut contribuer Ă©galement au dĂ©veloppement durable de la sociĂ©tĂ©. Les rĂ©sidus alcooliques constituent une catĂ©gorie Ă  fort potentiel de valorisation en diffĂ©rents types de produits chimiques. Dans ce contexte, la valorisation photocatalytique des rĂ©sidus alcooliques est une approche prometteuse du point de vue du dĂ©veloppement durable. L'objectif principal de la thĂšse Ă©tait d'Ă©tudier la valorisation photocatalytique de diffĂ©rents rĂ©sidus alcooliques biosourcĂ©s en produits Ă  valeur ajoutĂ©e. À cet Ă©gard, ces travaux ont principalement portĂ© sur (i) l'analyse des effets individuels et d'interaction des paramĂštres opĂ©ratoires et l'optimisation de la production d'hydrogĂšne Ă  partir de glycĂ©rol (ii) l'Ă©tude de la cinĂ©tique de la production d'hydrogĂšne Ă  partir de glycĂ©rol et d'Ă©thanol, (iii) la mise au point de catalyseurs nanocomposites au TiO2 utilisant des biomatĂ©riaux Ă  base de carbone (nanotubes de carbone et sphĂšres de carbone) pour la production d'hydrogĂšne Ă  partir de glycĂ©rol, et (iv) l'Ă©tude du mĂ©canisme et de la cinĂ©tique de la valorisation photocatalytique du cyclohexanol en cyclohexanone. Pour la production d’hydrogĂšne Ă  partir du glycĂ©rol, les modĂšles « RĂ©seau de neurones artificiels » ainsi que « MĂ©thode des surfaces de rĂ©ponses » ont Ă©tĂ© utilisĂ©s pour Ă©valuer l’effet et l’importance des principaux paramĂštres opĂ©ratoires (pourcentage de glycĂ©rol, catalyseur, et Pt (co-catalyseur), ainsi que pH). La comparaison de ces modĂšles a rĂ©vĂ©lĂ© une meilleure prĂ©cision du premier, qui a Ă©tĂ© par la suite sĂ©lectionnĂ©e pour une optimisation basĂ©e sur un algorithme gĂ©nĂ©tique. La plus grande quantitĂ© d'hydrogĂšne produite s'est rĂ©vĂ©lĂ©e ĂȘtre Ă  50% de glycĂ©rol dans l'eau (v/v), Ă  une masse de catalyseur de 3,9 g/L, Ă  3,1% de Pt et Ă  un pH de 4,5. Finalement, une analyse basĂ©e sur la mĂ©thode de Garson pour Ă©valuer l’importance relative des paramĂštres opĂ©ratoires a montrĂ© que les pourcentages de glycĂ©rol et de catalyseur affectent de façon diffĂ©rente la production d’hydrogĂšne. L'effet des plus importants paramĂštres opĂ©ratoires (catalyst loading, glycerol%, intensitĂ© de la lumiĂšre, and temps) sur la valorisation photocatalytique du glycĂ©rol en hydrogĂšne a Ă©tĂ© analysĂ© et un modĂšle cinĂ©tique a Ă©tĂ© dĂ©veloppĂ© sur la base d'un mĂ©canisme proposĂ©. La capacitĂ© du modĂšle Ă  prĂ©dire le taux de production d'hydrogĂšne pour diffĂ©rents substrats, photocatalyseurs et paramĂštres opĂ©ratoires a Ă©tĂ© confirmĂ©e en comparant les valeurs calculĂ©es avec des donnĂ©es expĂ©rimentales de la littĂ©rature. Le rĂŽle des composants carbonĂ©s (CT) biosourcĂ©es en tant que matrice, cocatalyseur et adsorbant dans les composites TiO2@CT a Ă©tĂ© Ă©tudiĂ© en utilisant des nanotubes de carbone et des sphĂšres de carbone. L'analyse morphologique a permis d'examiner le rĂŽle de la matrice et d’évaluer la formation uniforme du TiO2 sur le CT. Les expĂ©riences photocatalytiques ont Ă©tĂ© ensuite utilisĂ©es pour analyser les rĂŽles du co-catalyseur et de l'adsorbant. Fait intĂ©ressant, les rĂ©sultats ont rĂ©vĂ©lĂ© que l’incorporation de CNT dans un composite de TiO2 pouvait presque doubler le taux de production d’hydrogĂšne (i) en l’absence de Pt ou (ii) Ă  faible concentration en glycĂ©rol. Par consĂ©quent, il a Ă©tĂ© constatĂ© qu’en plus d’ĂȘtre une matrice, le CNT peut jouer deux autres rĂŽles importants, comme co-catalyseur et adsorbant. Pour Ă©valuer la valorisation des rĂ©sidus alcooliques en produits liquides Ă  valeur ajoutĂ©e, la conversion photocatalytique sĂ©lective du cyclohexanol en cyclohexanone a Ă©tĂ© investiguĂ©e par des Ă©tudes cinĂ©tiques et spectroscopiques. Un mĂ©canisme de rĂ©action a Ă©tĂ© proposĂ© sur la base des rĂ©sultats de l'analyse in situ ATR-FTIR et un modĂšle cinĂ©tique a Ă©tĂ© dĂ©veloppĂ© pour prĂ©dire le taux de production de cyclohexanone. Une trĂšs grande sĂ©lectivitĂ© de la cyclohexanone a Ă©tĂ© confirmĂ©e Ă  la fois par des analyses spectroscopiques que chromatographiques (HPLC et GC-MS), dĂ©montrant que l'approche photocatalytique est une alternative prometteuse pour la production sĂ©lective de cyclohexanone. En rĂ©sumĂ©, les rĂ©sultats de cette thĂšse ont montrĂ© que la photocatalyse est une alternative prometteuse pour la valorisation des rĂ©sidus alcooliques biosourcĂ©s en produits Ă  valeur ajoutĂ©. La conversion photocatalytique de ces rĂ©sidus peut conduire Ă  la production d'hydrogĂšne comme carburant vert prometteur pour l'avenir. D'autre part, la photocatalyse peut ĂȘtre appliquee pour produire des composes liquides avec une sĂ©lectivitĂ© Ă©levĂ©e.In the recent years, increasing attention has been paid to valorizing different types of waste materials to valuable chemicals. Waste valorization not only reduces the growing modern environmental issues, but also contributes to the sustainable development of the society. The alcoholic waste is an important category with high potential to be valorized into different types of valuable chemicals. As example, glycerol is a substantial alcoholic waste of biodiesel production process whose generation increased significantly during the recent years. In this context, photocatalytic valorization of alcoholic wastes is a promising approach from a sustainable development point of view. The main objective of the thesis was to study the photocatalytic valorization of different biobased alcoholic wastes to value-added products. In this regard, this work focused on (i) analyzing individual and interaction effect of operating parameters and optimization of hydrogen production from glycerol (ii) studying the kinetics of hydrogen production from glycerol and ethanol, (iii) developing TiO2 nanocomposite catalysts using biobased carbonaceous materials (carbon nanotubes and carbon spheres) and studding the roles of carbonaceous materials in hydrogen production from glycerol, and (iv) investigating the mechanism and kinetics of the photocatalytic valorization of cyclohexanol to cyclohexanone. For hydrogen production from glycerol, Artificial Neural Network (ANN) as well as Response Surface Methodology (RSM) models were employed to evaluate the effect and importance of the main operating parameters (glycerol%, catalyst loading, Pt (cocatalyst)%, and pH). Comparison of these models revealed that the ANN model had a better accuracy and it was therefore selected for a Genetic Algorithm-based optimization. The highest amount of hydrogen production was found to be at 50% glycerol in water (v/v), 3.9 g/L catalyst loading, 3.1% Pt, and pH of 4.5. Finally, a Garson’s method-based analysis of the relative importance of the operating parameters showed that the glycerol% and catalyst loading are, respectively, the least and most influential parameters on hydrogen production. The important operating parameters (catalyst loading, substrate%, light intensity, and time) of the process of photocatalytic valorization of glycerol and ethanol to hydrogen were analyzed and a kinetic model was developed based on a proposed mechanism. The ability of the model to predict the rate of hydrogen production for different substrates, photocatalysts, and ranges of operating parameters was confirmed by comparing the model predictions with the experimental data from literature. Carbon nanotube (CNT) and carbon sphere (CS) were used to prepare carbonaceous TiO2 composites and then the role of these biobased carbonaceous materials (CT) as template, cocatalyst, and adsorbent was investigated. The morphology analysis helped in examination of the template role and find the uniformity of the formed TiO2 on the template. On the other hand, the photocatalytic experiments assisted in the analysis of the cocatalyst and adsorbent roles of CT. Interestingly, the results revealed that CNT incorporation in TiO2 composite can almost double the rate of hydrogen production (i) in the absence of Pt or (ii) at low glycerol concentrations. Consequently, it was found that in addition to being a template, the CNT can play two important roles as cocatalyst and adsorbent. To evaluate the valorization of alcoholic wastes to valuable liquid product, photocatalytic selective conversion of cyclohexanol to cyclohexanone was analyzed kinetically and spectroscopically. A reaction mechanism was proposed based on the in-situ ATR-FTIR analysis results and a kinetic model was developed to predict the rate of cyclohexanone production. Experimental data were used to evaluate the kinetic parameters using genetic algorithm method and confirm the accuracy of model predictions. A very high selectivity of cyclohexanone was confirmed by both spectroscopic and chromatographic (HPLC and GCMS) analyses, demonstrating that the photocatalytic approach is a promising alternative for selective production of cyclohexanone. In summary, the results of this thesis showed that photocatalysis is a promising alternative for valorization of biobased alcoholic wastes to value-added products. Photocatalytic conversion of alcoholic wastes can lead to the production of hydrogen as a promising green fuel for the future. On the other hand, the conversion of alcoholic wastes can be engineered to produce valuable liquid product with high selectivity
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