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Thermal pasteurization is a technique widely utilized in the industry to reduce the microbial content of foods and increase their shelf life. The food pasteurization is commonly carried out in continuous process where the food undergoes to a rapid heating and a subsequent cooling with high heat transfer coefficients in order to reduce the degradation of main constituents like proteins and vitamins, and keeping almost unchanged the food organoleptic properties. Continuous pasteurization processes are commonly used to treat creams, tomato sauce, fruit juice, as well as products with solid particles or pieces like soups or baby foods. In such cases, the presence of dispersed large particles in the fluid can causes issues in the correct process setup. Indeed, the process setup must assure the pasteurization condition in the overall product food, included the centre of the particles. Here the heat penetrates by conduction and usually it becomes the actual limiting step of the process. In this work we estimate the pasteurization condition for a pilot scale pasteurization process for the thermal treatment of pear puree with pieces by the use of the Computational Fluid Dynamic approach. The results show that the heat penetration resistance into the solid particle reduces of about 32% the microbial abatement in the particle centre; however the P85 value results always higher than the minimum required for the food pasteurization. Copyright © 2014, AIDIC Servizi S.r.l.

Introduction: Predicting the timing and occurrence of kidney replacement therapy (KRT), cardiovascular events, and death among patients with advanced chronic kidney disease (CKD) is clinically useful and relevant. We aimed to externally validate a recently developed CKD G4+ risk calculator for these outcomes and to assess its potential clinical impact in guiding vascular access placement. Methods: We included 1517 patients from the European Quality (EQUAL) study, a European multicentre prospective cohort study of nephrology-referred advanced CKD patients aged ≥65 years. Model performance was assessed based on discrimination and calibration. Potential clinical utility for timing of referral for vascular access placement was studied with diagnostic measures and decision curve analysis (DCA). Results: The model showed a good discrimination for KRT and “death after KRT,” with 2-year concordance (C) statistics of 0.74 and 0.76, respectively. Discrimination for cardiovascular events (2-year C-statistic: 0.70) and overall death (2-year C-statistic: 0.61) was poorer. Calibration was fairly accurate. Decision curves illustrated that using the model to guide vascular access referral would generally lead to less unused arteriovenous fistulas (AVFs) than following estimated glomerular filtration rate (eGFR) thresholds. Conclusion: This study shows moderate to good predictive performance of the model in an older cohort of nephrology-referred patients with advanced CKD. Using the model to guide referral for vascular access placement has potential in combating unnecessary vascular surgeries.

Oil bodies (OBs) dispersed in an aqueous medium form a natural emulsion with high physical and microbiological stability. This work was focused on the development of a new protocol for extracting OBs from olive paste, through the extraction of an olive oil body cream (OOBC) with a yield of about 43% (wt/wt) in approximately 2 h. The proximate analysis revealed the presence of moisture, lipids and proteins as well as the contents of polyphenols and flavonoids, and the antioxidant powers were determined. The rheological and tribological performances of the OOBC were evaluated. Moreover, we measured a size distribution in the range of 0.7–1.7 m, by using a standard optical microscope. The results have demonstrated clearly that the OOBC extracted from the olive paste can be used as a functional and vegan ingredient in food emulsions.

Recently, vegetable oils have been widely used in several industrial fields as food additives, biofuels, cosmetic ingredients, packaging materials, or pharmaceutical compounds. In this study, we investigated the extraction of lipids from spent coffee grounds using an innovative system and the hydrofluorocarbon Norflurane, as solvent. Extraction experiments were performed on matrices at different levels of moisture under a recirculating solvent flow in the pressure range 5−11 bar. The results confirmed the effectiveness of the novel extraction process on wet, dried and partially dried matrices, and the oil yields and the extraction times (approximately 92% in 75, 90 and 285 min respectively) were comparable with those obtained using the more expensive supercritical CO2 process. A kinetic approach was used to model the extraction rates of wet, dry and partially dried samples. It showed that a partial drying of the SCG promoted the solubilization of oil in Norflurane during the first extraction stage and improved the contact between Norflurane and the oily solute. The fatty acid profiles of the extracts were determined and the results revealed the presence of palmitic (C 16:0) and linoleic (C 18:2) acids, as major components, and stearic (C 18:0) and oleic (C 18:1) acids, as minor components.

The enrichment of oils with nutraceutical bioactive phytomolecules allows the achievement of functional oil-based products of great interest in the food, pharmaceutical, and cosmetic fields. Carotenoids, such as lycopene and β-carotene, are available at a high concentration in tomatoes and tomato waste products, as peels, seeds, and pulp; their recovery is recently attracting growing interest and economic importance in the food industry, and also in consideration of the huge amount of industrial waste produced. The aim of this work is to study the production of an oil functionalized with carotenoids from tomato peels. The extractions were carried out using an innovative process based on the use of commercial Norflurane as solvent in subcritical conditions. Extraction trials were performed on dried tomato peels, with the addition of tomato seeds or wheat germ flour as sources of oily co-solvents, capable of also preserving the biological characteristics of the carotenoids extracted. Although lycopene solubility in Norflurane is quite low, the solvent recirculation and regeneration were allowed to reach a concentration in the oily extracts of approximately 0.3 mg/goil after 2 h of the process. The enrichment in β-carotene was more pronounced, and concentrations of 0.733 mg/goil and 0.952 mg/goil were observed in wheat germ and tomato seed oils, respectively. The results obtained in this study were compared with those obtained by traditional and supercritical CO2 extraction methods.

Background Depressive symptoms are associated with adverse clinical outcomes in patients with end-stage kidney disease; however, few small studies have examined this association in patients with earlier phases of chronic kidney disease (CKD). We studied associations between baseline depressive symptoms and clinical outcomes in older patients with advanced CKD and examined whether these associations differed depending on sex. Methods CKD patients (≥65 years; estimated glomerular filtration rate ≤20 mL/min/1.73 m2) were included from a European multicentre prospective cohort between 2012 and 2019. Depressive symptoms were measured by the five-item Mental Health Inventory (cut-off ≤70; 0–100 scale). Cox proportional hazard analysis was used to study associations between depressive symptoms and time to dialysis initiation, all-cause mortality and these outcomes combined. A joint model was used to study the association between depressive symptoms and kidney function over time. Analyses were adjusted for potential baseline confounders. Results Overall kidney function decline in 1326 patients was –0.12 mL/min/1.73 m2/month. A total of 515 patients showed depressive symptoms. No significant association was found between depressive symptoms and kidney function over time (P = 0.08). Unlike women, men with depressive symptoms had an increased mortality rate compared with those without symptoms [adjusted hazard ratio 1.41 (95% confidence interval 1.03–1.93)]. Depressive symptoms were not significantly associated with a higher hazard of dialysis initiation, or with the combined outcome (i.e. dialysis initiation and all-cause mortality). Conclusions There was no significant association between depressive symptoms at baseline and decline in kidney function over time in older patients with advanced CKD. Depressive symptoms at baseline were associated with a higher mortality rate in men.

Coeliac disease is an increasingly recognised pathology, induced by the ingestion of gluten in genetically predisposed patients. Undigested gliadin peptide can induce adaptive and innate immune response that unleash the typical intestinal mucosal alterations. A growing attention is paid to alternative therapeutic approaches to the gluten-free diet: one of these approaches is the use of probiotics and/or postbiotics. We performed lactic fermentation of rice flour with and without pH control, using Lactobacillus paracasei CBA L74 as fermenting strain. We evaluated bacterial growth, lactic acid production during fermentation and gliadin peptide P31-43 entrance in CaCo-2 cells with and without pH control. When pH control was applied no differences were observed in terms of bacterial growth; on the contrary, lactic acid production was greater, as expected. Both samples could inhibit the P31-43 entrance in CaCo-2 cells but the effect was significantly greater for samples obtained when the pH control was applied.

The mathematical modeling of fermentation processes allows for the formulation of predictions about the kinetics of biomass growth and metabolite production as well as setting or verifying the best operative conditions in view of the economical convenience of the process. For this purpose, we performed a kinetic study of a rice flour fermentation process using Lactobacillus paracasei CBA L74 with and without pH control, the pH value was set to 5.8 under pH control. Monod, Logistic, and Contois models were proposed to describe the bacterial growth rate in both conditions. The best mathematical model, which was able to describe the experimental data obtained without pH control, was the Contois model, as the specific growth rate was influenced by both the glucose reduction (from 14.31 g/L to 10.22 g/L) and the biomass production (2 log growth) that occurred during fermentation. Conversely, when pH control was implemented, both Monod and Contois models satisfactorily described the specific growth rate trend. The estimated kinetic parameters confirmed that biomass production (2 log growth) and glucose consumption (from 14.31 g/L to 6.06 g/L) did not affect the microorganism’s growth capacity when the fermenting medium was maintained at an optimal pH. The lactic acid production rate described by the Luedeking–Piret model did not appear to be linked to growth in the absence of pH control while, on the other hand, this model was unsuitable for describing the experimental lactic acid concentration when pH control was applied. The kinetic modeling of lactic acid production and the percentage of added glucose in the protocol with controlled pH will be optimized in the future.

Cereals are becoming interesting substrates to be fermented to obtain new functional foods. For this reason, an enzymatic pretreatment of a wheat flour suspension using amylase was investigated in order to guarantee the feasibility to ferment a cereal-based substrate at a solid content higher than that used in past experimentations. Trials with and without amylase pretreatment, using a 52% w/v wheat flour water suspension, were carried out to evaluate the fermentation feasibility; mixing tests with a food dye were performed to verify the suspension homogeneity. The pretreated suspension, whose starch was hydrolyzed for about 80% by α-amylase, was then fermented (37°C, 24h) by Lactobacillus paracasei CBA-L74. Starting from pH value 5.75, microbial concentration 1.89 × 106 CFU/ml and lactic acid 0 mg/L, final values of 3.93, 3 × 108 CFU/ml and 6,251 mg/L were found after 24 hr of fermentation. The untreated suspension went to gelation and was impossible to ferment because its consistency was like a dough and the mixing system was not suitable to ensure mixing. Practical applications: The aim of the present study was the handling and the fermentation of cereal-based substrate at high solid content (52% w/v), through a preliminary amylase pretreatment. The fermentation of such a solid content could guarantee the production of a greater quantity of solid fermented matrix and this could considerably reduce drying times with greater productivity at a low cost.

In this article, the charge trapping phenomena in Al2O3 thin films grown by atomic layer deposition (ALD) on AlGaN/GaN heterostructures have been studied by time-dependent capacitance–voltage (C-V) measurements as a function of temperature. In particular, monitoring the transient of the capacitance enabled us to estimate the maximum depth of the insulating layer interested by the negative charge trapping effect under our bias stress conditions and to determine a charge traps density in the bulk Al2O3 in the order of 3 × 1019 cm−3. A temperature dependent C-V analysis up to 150 °C demonstrated the presence of two competitive mechanisms that rule the electron capture and emission in the Al2O3 film, characterized by activations energies of 22 and 88 meV respectively. Photoluminescence analyses revealed the presence of oxygen-related point defects in the insulator with a concentration in the order of ∼1020 cm−3 envisaging that only a fraction of them is electrically active. The results are useful to establish the thermal stability of the trapping phenomena, and the possible application in real devices.

In this work, the nucleation and growth mechanism of aluminum oxide (Al2O3) in the early stages of the direct atomic layer deposition (ALD) on monolayer epitaxial graphene (EG) on silicon carbide (4H-SiC) has been investigated by atomic force microscopy (AFM) and Raman spectroscopy. Contrary to what is typically observed for other types of graphene, a large and uniform density of nucleation sites was observed in the case of EG and ascribed to the presence of the buffer layer at EG/SiC interface. The deposition process was characterized by Al2O3 island growth in the very early stages, followed by the formation of a continuous Al2O3 film (2.4 nm thick) after only 40 ALD cycles due to the islands coalescence, and subsequent layer-by-layer growth. Raman spectroscopy analyses showed low impact of the ALD process on the defects density and doping of EG. The EG strain was also almost unaffected by the deposition in the regime of island growth and coalescence, whereas a significant increase was observed after the formation of a compact Al2O3 film. The obtained results can have important implications for device applications of epitaxial graphene requiring the integration of ultra-thin high-k insulators., 19 pages, 6 figures

Studies of the ability of probiotics to ferment cereal flours are necessary to obtain products with enhanced nutritional value. In this study, Lactobacillus paracasei CBA-L74 was used to ferment cereal aqueous mixtures containing both oat (7.5% w/v) and rice flours (7.5% w/v), with and without glucose, to understand whether glucose addition could have any effect on growth and metabolism. Viability, pH, metabolites production during fermentation (24 h, 37 °C) and substrates reduction were analysed. The strain showed good growth in the cereal aqueous mixture both with and without glucose addition, but suspensions prepared with glucose showed the best results. A bacterial concentration of 7 log CFU mL−1, a pH value of 4.70 and lactic acid production of 1250 mg L−1 were achieved when fermentation was performed without glucose addition, while in the presence of glucose, a t24 bacterial growth of 8 log CFU mL−1 was reached, with a pH value of 3.11 and lactic acid production of 6050 mg L−1., Food science, Food technology, Nutrition, Lactobacillus paracasei CBA L74, Fermented food, Rice flour, Oat flour, Glucose, Probiotics

The consumption of vegetable oils has increased in recent years due to their nutraceutical properties. There is growing scientific research interest in the development of innovative, efficient and sustainable extraction techniques capable of separating lipid fractions from vegetal matrices. In this study, we introduce an innovative technique for extracting lipids from bilberry seeds that uses Norflurane, a hydrofluorocarbon, as the solvent under subcritical conditions. Preliminary extraction experiments were carried out using bilberry seeds in the waste material from the bilberry drupe valorization process. Different granulometric bilberry fractions were selected, suitably crushed, and sized prior to extraction. An extraction efficiency of 91% of the total lipid content was obtained for the ground fraction with grains 450−710 μm in size. The main fatty acids present in the lipid extracts were oleic, linoleic and α-linolenic acids. The ratio of unsaturated-to-saturated fatty acids was determined to be 11.63, with a ω6/ω3 ratio of 1.06.

The feasibility of developing a dry legume-based functional product using a fermentation process carried out on a 10% w/v navy bean suspension, in a lab-scale stirred batch reactor was studied. After soaking and cooking dried navy beans, the fermentation tests performed on the resulting medium using Lactobacillus paracasei CBA L74 showed a maximum bacterial count of 109 CFU/mL after 20 hr and a maximum lactic acid concentration of 1.9 g/L after 16 hr of process time. A freeze-drying process was conducted on the fermented bean suspension, showing a two-log microbial reduction and a bacterial viability in the resulting probiotic powder of 3.7 × 108 CFU/g.

Banana puree, due to its nutritional composition, is a good substrate for fermentation in the development of probiotic products. The production of banana puree mainly consists of three phases, i.e., raw material pretreatment, heat treatment, and the addition of anti-browning agents. In this study, we conducted three experimental protocols to evaluate the effect of ripeness grade, heat treatment, and ascorbic acid addition on fermentation performance. At the end of each protocol, the substrate was subjected to the fermentation process (37 °C, 48 h), and then measurements of pH reduction, microbial growth, and lactic acid production were used as markers in the analysis of fermentation performance. Ripe bananas produced better results than unripe bananas whose fermentation appeared to be inhibited. Therefore, ripe bananas were used to test the effect of two different heat treatments (sterilization (121 °C, 20 min) versus tyndallization (70 °C, 30 min, 37 °C, 30 min, 70 °C, 30 min)) on banana puree fermentation, and no significant differences were observed. Finally, 500 or 1000 ppm of ascorbic acid, normally used as an anti-browning agent, was added to ripe tyndallized bananas. No differences in fermentation results were observed between the two tested conditions, though values obtained for growth and lactic acid production were significantly lower than those from fermentation of banana puree without ascorbic acid.

The structural and the electronic properties of monolayer graphene made by chemical vapor deposition and transferred on various oxide substrates ( SiO 2 , Al 2 O 3 , and HfO 2 ) are investigated by Raman Spectroscopy and Atomic Force Microscopy in order to highlight the influence of the substrate on the features of p-doping obtained by O 2 thermal treatments. By varing the treatment temperature up to 400 °C, the distribution of the reaction sites of the substrates is evaluated. Their total concentration and the consequent highest doping available is determined and it is shown that this latter is linked to the water affinity of the substrate. Finally, by varing the exposure time to the gas up to 2 h, the kinetics of doping is investigated. The doping process is found to be better described by a diffusion limited kinetic model, ascribable to the diffusion of O 2 in the interstitial space between graphene and the substrate. After this step, the doping process is completed by a faster redox reaction between O 2 adsorbed to graphene and interstitial H 2 O .

The Mexican border between journalistic chronicle and fictional narrative. Journalistic chronicle as a literary reconstruction of facts or people invites us to pose certain questions, such as the whether this genre can be placed in between history and literature and what kind of a role testimony plays in its creation. I am here proposing an analysis of three novels written by Diego Enrique Osorno, Alejandro Hernández and Antonio Ortuño on the topic of the Northern and Southern Mexican border in order to suggest a connection between these two genres and highlight points of difference and similarity. La crónica periodística como la reconstrucción literaria de sucesos o figuras nos invita a plantearnos algunas preguntas, como la posibilidad de colocar este género entre la historia y la literatura, y la función que tiene el testimonio en su elaboración. Propongo el análisis de tres novelas escritas por Diego Enrique Osorno, Alejandro Hernández y Antonio Ortuño sobre el tema de la frontera mexicana del norte y del sur, para plantear la relación entre ambos géneros, marcar distinciones y señalar puntos en común.

This study reports experimental results on the primary jet breakup parameters of three hollow cone hydraulic spray nozzles electrified by induction. While former evidence indicated that the properties of sprayed droplets are scarcely affected by induction charging, we found that an increase in charging potential from 0 kV to −10 kV led to a reduction of breakup length and an increase of spray angle. For charging potential from −10 kV and −12 kV both the parameters reached asymptotic levels. As for electrosprays, we argue that jet breakup reduction modifications depend on the establishment of electrical stresses over the water sheet, while spray angle enlargements depend on the repulsion forces caused by induced charges. In most of the cases, these modifications are not sufficient to change the secondary atomization regime, but they severely affect the charging level of sprayed droplets.

Le pratiche di questua sono azioni rituali che caratterizzano diversi periodi festivi di tutta l’area euro-mediterranea. Si tratta di richieste di dazione e prelievi di beni (generalmente alimenti) eseguite, secondo diverse modalità e entro precisi segmenti spazio-temporali, da soggetti tradizionalmente demandati a rivestire il ruolo di postulanti (comitati, confratrie, compagnie di adulti, giovani, bambini/e; spesso ma non sempre connotati da speciali costumi e/o maschere e da altri simboli materiali nonché da specifici e peculiari comportamenti). L’auspicata e prefigurata (nelle formule di questua) dazione degli offerenti presuppone un dono da parte dei questuanti che assume spesso, ma non necessariamente, una dimensione performativa: esecuzioni musicali e coreutiche, drammatizzazioni, canti, recite di testi si accompagnano e aggiungono infatti, in diverse circostanze, al semplice scambio tra beni e formule/gesti di contenuto augurale. Clemente le definisce, pertanto, questue-cerimonie e, sottolineando il rapporto prestazione (performance dei questuanti)–controprestazione (dazione dei riceventi), le ascrive entro la categoria delle azioni cerimoniali itineranti con scambio. Va osservato, tuttavia, che ciò che caratterizza e qualifica inequivocabilmente le questue a carattere rituale è lo scambio tra beni immateriali (l’augurio di benessere e prosperità) e beni materiali (gli alimenti, il denaro), restando l’eventuale prestazione performativa solo funzionale e non determinante rispetto alla definizione del rito. Ciò in ragione del fatto che i postulanti sempre e comunque rappresentano nel contesto cerimoniale delle autentiche “figure dell’alterità”, proponendosi (esplicitamente o implicitamente) come rappresentanti e/o emissari di potenze extraumane da cui ci si attendono benevolente attenzione e protezione, ossia un contro-dono diffuso e differito nel tempo. Sulla base di queste considerazioni quanto viene offerto ai questuanti non può essere semplicisticamente inteso come retribuzione di una qualsivoglia prestazione ovvero come parte di un meccanismo redistributivo sostenuto da istanze di ordine sociale o di pietas religiosa, e conferma come questi riti vadano complessivamente considerati, almeno da un punto di vista genetico, come occasioni in cui offrire il dono periodicamente dovuto alle forze e alle entità che garantiscono l’equilibrio cosmico e microcosmico, i cicli della natura e della vita sociale. THE FATE IN WORDS. ALMS-GIVING, MASKINGS AND WELL-WISHING FORMULAS Alms-giving is a ritual practice which characterizes several festivities in the whole Euro-Mediterranean area. It consists in requests for offers or collection of goods (usually food) performed following different modalities and within precise space-time segments, by subjects traditionally appointed to assume the role of postulants (associations, confraternities, groups of adults, youths, children; often but not always connoted by special costumes and/or masks and by material symbols as well as by specific and peculiar behaviours). The offerers' donation desired and prefigured in alms formulas presupposes a gift given by the collectors of alms; this gift often assumes a performative dimension, although it is not necessarily so: music and choreutic performances, dramatizations, songs, recital of texts accompany them and, as a matter of fact, they join the simple exchange of goods and well-wishing gestures or formulas, in several circumstances. Clemente thus defines them as alms-cerimonies and, underlining the nexus performance (the postulants' one)-counterperformance (donation of the receivers), he ascribes them within the category of cerimonial itinerant actions with exchange. However, we must remark that what characterizes and qualifies unequivocally ritual alms-giving is the exchange of immaterial goods (the wish for wealth and prosperity) and material goods (food, money), while the possible performance remains merely functional and it is not decisive with respect to the definition of the rite. This because postulants in any case always represent some authentic "figures of otherness" in the ceremonial context (explicitly or implicitly) proposing themselves as representatives and/or emissaries of extra-human powers from whom benevolent care and protection are expected, that is a counter-gift diffused and deffered in time. On the basis of such observations, what is offered to the collectors of alms cannot be simplistically understood as payment for any performance whatsoever or as part of a redistribution mechanism supported by demands of social order or of religious pietas, and it confirms that on the whole, at least from a genetic point of view, such rites are to be considered as occasions upon which to offer the gift periodically due to the forces and entities which guarantee the cosmic and microcosmic balance, the cycles of nature and of social life.

This paper aims to investigate the suitability of geopolymer mortars for strengthening existing reinforced concrete structures. Mortars were realized by mixing carbon fly ash with sodium silicate and sodium hydroxide solutions and sand. Several mixtures were prepared by varying the molar concentration of sodium hydroxide solution. Physical and mechanical properties of the hardened mortars were evaluated after 7 and 28 days of curing at room temperature. Geopolymer mortars were then used as matrix to cast fiber reinforced geopolymer matrix (FRGM) composites, comprised of high-strength steel fibers. The composites were applied on one face of concrete prisms and the bond behavior of the FRGM–concrete joints was investigated using single–lap direct shear test setup. Results show that geopolymer mortars can potentially replace cementitious mortar used in fiber reinforced inorganic matrix composites for strengthening applications of existing reinforced concrete structures.

A cold plasma prototype electrode discharge apparatus to perform polymer surface treatment is described. The plasma generator, operating with oxygen and/or nitrogen, works in glow regime at low pressure (10 mbar) and at relatively high gas flow rate, in the 110–340 1/h range. The effects of treatments on PET monopolyester and glass fibre reinforced plastics (GFRP) surfaces are analysed. The treatment points out, in all operating conditions, an increase of both wettability (PET) and adhesivity (GFRP). The treatment times obtained are one order of magnitude lower than those of the traditional treatment apparatus.

The present study analyses the performance of a scraped surface heat exchanger (SSHE) equipped with a new arrangement of blades to achieve higher thermal efficiencies than the conventional SSHE. This new design of exchanger, named here as scraped surface heat exchanger with alternate blades, A-SSHE, may be particularly suited to treat high viscous fluids, like food pastes. Experimental and numerical tests were carried out on an industrial scale A-SSHE used to heat hazelnut paste, an intermediate product widely used in Italian confectionery industry. Experimental tests include physical, chemical and rheological characterization of the hazelnut paste and the evaluation of the overall heat transfer coefficient as a function of rotational speeds and mass flow rates. Three-dimensional axial-symmetric CFD simulations of the A-SSHE were performed by using the software Fluent 6.2. For comparison, the same numerical tests were carried out for an equivalent SSHE with a conventional blades design (C-SSHE). Our studies show that the A-SSHE gives heat transfer coefficient values almost twice that of an equivalent C-SSHE, and that the numerical results are consistent with the experimental observations. The analysis of the fluid dynamics and of the thermal profiles suggests that the higher heat transfer efficiency of A-SSHE may be attributed to the occurrence of backmixing phenomena.

Zn-doped TiO2 nanofibers shelled with ZnO hierarchical nanoarchitectures have been fabricated combining electrospinning of TiO2 (anatase) nanofibers and metal-organic chemical vapor deposition (MOCVD) of ZnO. The proposed hybrid approach has proven suitable for tailoring both the morphology of the ZnO external shell as well as the crystal structure of the Zn-doped TiO2 core. It has been found that the Zn dopant is incorporated in calcined electrospun nanofibers without any evidence of ZnO aggregates. Effects of different Zn doping levels of Zn-doped TiO2 fibers have been scrutinized and morphological, structural, physico-chemical and optical properties evaluated before and after the hierarchical growth of the external ZnO shell over the electrospun nanofibers. Moreover, doping promotes the incipient transition from the anatase to rutile phase in the core-shell Zn-doped TiO2-ZnO nanostructures at lower temperature than that observed for pure TiO2. Finally, the present core-shell hierarchical nanofibers possess a very large surface to volume ratio and exhibit a marked cathodoluminescence with a strong UV and visible emission.

Bayreuth

St. Paul, Minnesota

Helsinki