1,872 research outputs found
Hematite Clusters on Anatase TiO2 Surface and Effect of Oxygen Vacancy: A First Principles Study
It has been observed that small Fe2O3 clusters at low coverage on TiO2 can
enhance the photocatalytic activity, while increase in concentration and size
of the iron oxides can hinder it. Previously, TiO2/Fe2O3 composites have been
studied using DFT methods and explained a photo electron transfer from TiO2 to
Fe2O3. Nevertheless, a systematic study by increasing the size and coverage
concentration of Fe2O3 clusters on the anatase surface can give more insights
into observed photocatalytic activity. In this scenario, keeping this as a
guideline, we have simulated adsorption of Fe2O3 clusters at the anatase TiO2
(101) surface. We investigated the structural, electronic and magnetic
properties to understand the photocatalytic system. Adsorption of the clusters
at the surface is exothermic and generates impurity states in the band gap
which narrows the band gap. Notable charge transfer is attributed to a
formation of heterojunction between TiO2 and Fe2O3 cluster. These findings
indicate TiO2 to be a better photocatalyst with hematite clusters at low
coverage. We also introduced oxygen vacancy in the heterostructure to study the
possibility of altering the photocatalytic properties. We find that oxygen
vacancy further alters the electronic properties, and also locally affects the
magnetic properties. The results suggest that introduction of oxygen vacancy
can be a promising routine to modify the photocatalytic performance of TiO2.Comment: 20 pages, 13 figure
Comparaison de la biotolérance de l’huile extraite de l’arille de Blighia sapida (K. Koenig), des huiles de palme et d’olive chez le rat
Afin de valoriser l’huile extraite de l’arille de Blighia sapida, les effets toxiques de cette huile ont été comparés aux effets toxiques possibles de deux huiles très consommées à travers le monde (huile d’olive et huile de palme). Cette étude s’est faite expérimentalement sur 54 rats mâles adultes de genre Albinos Wistar. Ces derniers ont été divisés en 9 groupes homogènes (6 par groupe) et ont reçu par gavage (2 fois par semaine pendant 4 semaines) les trois types d’huiles à trois volumes croissants 0,5mL ; 1mL ; 2mL. Tous les animaux ont survécu pendant la durée de l’expérimentation et les différents groupes ne présentaient apparemment pas de différence de signes cliniques. La comparaison des moyennes des paramètres hématologiques entre d’une part, les rats ayant reçu l’huilede palme et ceux ayant reçu l’huile extraite de l’arille de Blighia sapida et, d’autre part, entre les rats ayant reçu l’huile d’olive et ceux ayant reçu l’huile extraite de l’arille de Blighia sapida ne montrait pas de différence significative (p>0,05). Il en est de même pour la comparaison des moyennes des taux de triglycérides, de cholestérol Total, de cholestérol-HDL et de bilirubines totale et conjuguée. Le taux de cholestérol et le ratio cholestérol montraient tous deux une élévation significative (p<0,05) liée à l’administration d’huile de palme que l’administration d’huile extraite de l’arille de Blighia sapida, à partir de 1mL comme volume administré. Par contre, quel que soit le volume administré, le taux de cholesterol-LDL et le ratio cholestérol chez les rats ayant reçu l’huile extraite de l’arille de BHS était quasi-similaire à ceux des rats ayant reçu de l’huile d’olive (p>0,05). Comme ces huiles (huile d’olive et huile de palme) sont de consommation courante, alors, ces résultats ouvrent des perspectives intéressantes relatives à l’utilisation de l’huile extraite de l’arille de Blighia sapida en alimentation.Mots-clés : arille, huiles, effets toxiques, rats, gavage
Les produits et sous-produits du bananier dans l’alimentation animale
L’objectif de ce travail est de montrer que les produits et sous-produits du bananier peuvent être incorporés dans l’alimentation animale sans risque. Ces produits et sous-produits agricoles ont été plusieurs fois utilisés dans l’alimentation des ruminants, du porc, du lapin et de la volaille sous forme ensilée, farineuse ou hachée à des taux variables. Les résultats obtenus sont comparables à ceux obtenus avec des aliments couramment utilisés en élevage. Les feuilles du bananier, le son pseudo-tronc, la banane et ses déchets peuvent servir dans l’alimentation animale
Prolonged transition time between colostrum and mature milk in a bear, the giant panda, Ailuropoda melanoleuca
Bears produce the most altricial neonates of any placental mammal. We hypothesized that the transition from colostrum to mature milk in bears reflects a temporal and biochemical adaptation for altricial development and immune protection. Comparison of bear milks with milks of other eutherians yielded distinctive protein profiles. Proteomic and metabolomic analysis of serial milk samples collected from six giant pandas showed a prolonged transition from colostrum to main-phase lactation over approximately 30 days. Particularly striking are the persistence or sequential appearance of adaptive and innate immune factors. The endurance of immunoglobulin G suggests an unusual duration of trans-intestinal absorption of maternal antibodies, and is potentially relevant to the underdeveloped lymphoid system of giant panda neonates. Levels of certain milk oligosaccharides known to exert anti-microbial activities and/or that are conducive to the development of neonatal gut microbiomes underwent an almost complete changeover around days 20–30 postpartum, coincident with the maturation of the protein profile. A potential metabolic marker of starvation was detected, the prominence of which may reflect the natural postpartum period of anorexia in giant panda mothers. Early lactation in giant pandas, and possibly in other ursids, appears to be adapted for the unique requirements of unusually altricial eutherian neonates
Substitution de la farine de poisson par la farine d’asticots séchés dans le régime du rat en croissance : Risques pathologiques ?
Deux groupes de dix rats en croissance sont nourris durant 15 jours, avec deux régimes alimentaires ne différant que par la qualité de leurs protéines animales. L’un contient 10% de farine de poisson (témoin) et l’autre, 10% de farine d’asticots séchés (FAS). Le dosage des paramètres biochimiques plasmatiques et la biométrie des reins et des foies sont effectués chez tous les rats en fin d’expérience. Aucune pathologie ni anomalie physiologique n’a été décelée à travers les paramètres biochimiques plasmatiques. Mais, la biométrie des organes révèle chez les rats sous régime FAS, une diminution de 6,60% du poids des reins et une augmentation de 10,60% du poids des foies, en comparaison aux sujets témoins. Ces résultats pourraient présager une pathologie ou une perturbation du métabolisme nutritionnel de ces organes
Genesis of alpinotype fissure minerals from Thasos Island, Northern Greece - Mineralogy, mineral chemistry and crystallizing environment.
Στην περιοχή της Θάσου, αλπινότυπα ορυκτά φιλοξενούνται εντός διακλάσεων γνευσίων, αμφιβολιτών, Mn-ούχων ασβεστοπυριτικών στρώσεων και σχιστολίθωνκαθώς και μάρμαρων της κατώτερης ενότητας του μεταμορφικού πυρήνα της Ροδόπης. Οι αλπινότυπες διακλάσεις τέμνουν τις μεταμορφικές δομές και συνδέονται στενά με τις διαδικασίες εκταφιασμού του Ροδοπικού συμπλέγματος κατά το Ολιγόκαινο-Μειόκαινο. Οι περισσότερες αλπινότυπες διακλάσεις αναπτύσσονται κατά μήκος μίας μεγάλης ζώνης αποκόλλησης, που διαχωρίζει τους ανώτερους στρωματογραφικά γνεύσιους από τους κατώτερους αμφιβολίτες και μάρμαρα. Το ορυκτολογικό περιεχόμενο των διακλάσεων είναι στενά συνδεδεμένο με την ορυκτολογία των περιβαλλόντων πετρωμάτων. Σε διακλάσεις εντός αμφιβολιτών εμφανίζεται αδουλάριος, αλβίτης, χαλαζίας, τιτανίτης, απατίτης, ακτινόλιθος, χλωρίτης, ασβεστίτης, αιματίτης και ρουτίλιο. Σε διακλάσεις παρα-, ορθογνευσίων και μεταπηγματιτών κρυσταλλώνονται χαλαζίας, αδουλάριος, μοσχοβίτης και αιματίτης, ενώ σε διακλάσεις που αναπτύσσονται εντός σπεσσαρτινικών-πιεμοντιτικών σχιστόλιθων κρυσταλλώνονται χαλαζίας, χλωρίτης, σπεσσαρτίνης, αιματίτης, ρουτήλιο, αλβίτης, επίδοτο και ζιρκόνιο. Τέλος διακλάσεις εντός ασβεστοπυριτικών στρώσεων περιέχουν Mn-ούχο γροσσουλάριο, χαλαζία και Mn-ούχο κλινοζωισίτη. Οι εξαλλοιώσεις που παρατηρούνται στα τοιχώματα των διακλάσεων υποδηλώνουν διαδικασίες u941 .κπλυσης των περιβαλλόντων πετρωμάτων από υδροθερμικά ρευστά. Οι κρύσταλλοι χαλαζία εμφανίζονται με μορφές σκήπτρου, σε πρισματικούς κρυστάλλους διάφορων γενεών να αναπτύσσονται πάνω σε χαλαζίες τύπου Τessin, υποδηλώνοντας πολλαπλά στάδια κρυστάλλωσης και αλλαγή των συνθηκών P-T-t. Η εφαρμογή γεωθερμόμετρου χλωρίτη υποδεικνύει αρχικές θερμοκρασίες σχηματισμού των παραγενέσεων τους 286 έως 366 °C. Οι χαλαζίες τύπου Τessin πιθανότατα δημιουργήθηκαν από ρευστά πλούσια σε CO2 και πιθανόν στη μετάβαση από ένα συμπιεστικό σε εφελκυστικό τεκτονικό καθεστώς. Αντίθετα οι μεταγενέστερες γενεές σκήπτρων υποδεικνύουν συμμετοχή κατερχόμενων μετεωρικών νερών. Η περιοχή μελέτης αντιπροσωπεύει μοναδικό ορυκτολογικό Γεώτοπο. Η γεωλογική-ορυκτολογική αυτή κληρονομιά μπορεί να προστατευθεί μέσω της ίδρυσης ενός Γεωπάρκου που θα συμβάλει επιπλέον και στην προώθηση φιλικής προς το περιβάλλον ανάπτυξης της Θάσου.Alpinotype fissure-minerals in Thasos Island are hosted in gneisses, amphibolites, Mn-rich schists and calc-silicate layers, and marbles of the Carboniferous-Permian Pangeon Unit, which represents the lower tectonostratigraphic unit of the southern Rhodope metamorphic core complex. Alpinotype fissures crosscut metamorphic fabrics and are closely related to the exhumation processes of the core complex during the Oligocene-Miocene. Most mineralized fissures occur close to a major detachment fault, which separates gneisses from marbles and amphibolites. The mineralogy of the alpinotype fissures is closely related to the host rocks: amphibolite-hosted fissures include adularia, albite, quartz, titanite, apatite, actinolite, chlorite, calcite, hematite and rutile. Fissures in para- and orthogneisses- and in metapegmatites are characterized by smoky and clear quartz, adularia, muscovite and hematite. Fissures within spessartite-piemontite schists contain quartz, chlorite, spessartite, hematite, rutile, albite, epidote and traces of zircon. Finally fissures in calc-silicate layers include Mn-grossular, quartz and Mn-clinozoisite. Hydrothermal alteration halos surrounding the fissures may suggest leaching of the wall rocks as a potential mechanism for mineral deposition. Scepter quartz crystals consist of a lower Tessinhabit crystal and several generations of upper prismatic quartz crystals, suggesting several stages of crystallization and changing P-T-x conditions with time. Chlorite geothermometry indicates temperatures of formation in the range between 286 and 366 °C. Tessin habit quartz was deposited from CO2-bearing fluids, probably at the transition from a compressional to an extensional tectonic regime and was later dissolved by meteoric water dominated fluids resulting in the formation of quartz scepters. Oxidizing conditions are indicated by the widespread occurrence of hematite in the mineralization. The studied area represents a unique mineralogical geotope. Its geological-mineralogical heritage should be protected through establishment of a mineralogical-petrological geopark that will also promote sustainable development of the area
Profils Sociodemographique, Economique Et Alimentaire Chez Des Enfants Malnutris Aigus, Ages De 06 A 59 Mois, Reçus Au Centre Hospitalier Universitaire De Treichville (Abidjan-Cote D’ivoire)
In this descriptive and transversal work, the main objective is to establish the socio-demographic, economic and nutritional profiles of the children, aged between 06 and 59 months, acutely malnourished, consulted and / or hospitalized in pediatric emergency departments and Of the University Hospital of Treichville (UHT). This study is conducted on 290 children, aged between 06 and 59 months. A questioning anthropometric, socio-demographic, economic and food data allows the diagnosis of the nutritional status of each child and the descriptive statistical analysis of the patient. The results show that the prevalence of acute malnutrition is 55.86%, with 35.17 % cases of severe acute malnutrition and 20.68 % of cases of moderate acute malnutrition. The population of acute malnourished children in this study consisted of 84 girls and 78 boys, a sex ratio of 0.928. The children (133) victims of this type of malnutrition come, predominantly and significantly, from the precarious habitats. 126 have out-of-school mothers and 129 have consumed food of diversification or poor quality supplement. In 110 acute malnutrition, the daily family food budget is between 1500 FCFA and 3000 FCFA. At last, the index of food consumption score, also called food consumption, is referred to as a limit in 98. Finally, in this study, the risk factors having a significant impact on nutritional status are the precariousness of the habitat Place of residence), maternal education, complement food quality or diversification, food insecurity, age of complement and current diet
Fluoroquinolone-related adverse events resulting in health service use and costs : A systematic review
Background and objectives Adverse events (AEs) associated with the use of fluoroquinolone antimicrobials include Clostridium difficile associated diarrhea (CDAD), liver injury and seizures. Yet, the economic impact of these AEs is seldom acknowledged. The aim of this review was to identify health service use and subsequent costs associated with ciprofloxacin, levofloxacin, moxifloxacin, norfloxacin and ofloxacin -related AEs. Methods A literature search covering Medline, SCOPUS, Cinahl, Web of Science and Cochrane Library was performed in April 2017. Two independent reviewers systematically extracted the data and assessed the quality of the included studies. All costs were converted to 2016 euro in order to improve comparability. Results Of the 5,687 references found in the literature search, 19 observational studies, of which five were case-controlled, fulfilled the inclusion criteria. Hospitalization was an AE-related health service use outcome in 17 studies. Length of hospital stay associated with AEs varied between <5 and 45 days. The estimated cost of an AE episode ranged between 140 and 18,252 (sic). CDAD was associated with the longest stays in hospital. Ten studies reported AE-related length of stays and five evaluated costs associated with AEs. Due to the lack of published literature, health service use and costs associated with many high-risk FQ-related AEs could not be evaluated. Conclusions Because of the wide clinical use of fluoroquinolones, in particular serious fluoroquinolone-related AEs can have substantial economic implications, in addition to imposing potentially devastating health complications for patients. Further measures are required to prevent and reduce health service use and costs associated with fluoroquinolone-related AEs. Equally, better-quality reporting and additional published data on health service use and costs associated with AEs are needed.Peer reviewe
From multiple perspectives to shared understanding
The aim of this study was to explore how learners operating in a small group reach shared understanding as they work out joint research questions and build a theoretical framework and to identify the resources and tools they used in the process. The learners’ own interpretations of their group activities and learning were also taken into account. The data, consisting of group discussions and the documents produced by the group, were subjected to a qualitative content analysis. The group members employed a variety of resources and tools to exchange their individual perspectives and achieve shared understanding. Summaries of relevant literature laid a foundation for the group’s theoretical discussions. Reflective comparisons between their book knowledge and their personal experiences of online interaction and collaboration were frequent, suggesting that such juxtapositions may have enhanced their learning by intertwining the content to be mastered and the activities entailed by this particular content
Blue mussel shell shape plasticity and natural environments: a quantitative approach
Shape variability represents an important direct response of organisms to selective environments. Here, we use a combination of geometric morphometrics and generalised additive mixed models (GAMMs) to identify spatial patterns of natural shell shape variation in the North Atlantic and Arctic blue mussels, Mytilus edulis and M. trossulus, with environmental gradients of temperature, salinity and food availability across 3980 km of coastlines. New statistical methods and multiple study systems at various geographical scales allowed the uncoupling of the developmental and genetic contributions to shell shape and made it possible to identify general relationships between blue mussel shape variation and environment that are independent of age and species influences. We find salinity had the strongest effect on the latitudinal patterns of Mytilus shape, producing shells that were more elongated, narrower and with more parallel dorsoventral margins at lower salinities. Temperature and food supply, however, were the main drivers of mussel shape heterogeneity. Our findings revealed similar shell shape responses in Mytilus to less favourable environmental conditions across the different geographical scales analysed. Our results show how shell shape plasticity represents a powerful indicator to understand the alterations of blue mussel communities in rapidly changing environments.The work was funded by the European Union Seventh Framework Programme, Marie Curie ITN under grant agreement n° 605051
- …