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Nanoparticles and nanopores of iron oxide were synthesized by electrochemical anodization, in an electrolytic medium of ammonium fluoride (NH4F), deionized water and ethylene glycol. After anodization, the Fe foils were annealed at 450 °C for 2 hours. Different anodization times and two concentrations of NH4F (0.1 M and 1.2 M) were evaluated, under static conditions at room temperature. Scanning Electron Microscopy showed nanopores (0.1 M) and nanoparticles (1.2 M). Eight vibration modes characteristic of α-Fe2O3 were found with Raman spectroscopy technique. Relationship between the modes Eu(LO) and 2Eu(LO) was found, therefore, their association with the disorder in the crystalline structure can be determined and it was also found that 2Eu(LO) intensity mode at a concentration of 1.2 M is larger than 0.1 M nanostructures, the FWHM of the A1g mode at 227 cm-1 corresponding to the Fe3+ ions and the Eg at 293 cm-1 mode caused by the O2- ions was also analyzed and founded that the crystalline structure of hematite can be determined by the A1g mode at 227 cm-1.
In this work, the anodization of grade 2 titanium was performed using a HCl-based electrolyte in order to obtain Titania nanostructures. Different glycerol concentrations were added to the HCl electrolyte to study the effect it has on the shape and density of the nanostructures, additionally, anodization time and voltage was also varied. The anodized samples were observed by SEM microscopy and studied by Raman spectroscopy and X-ray diffraction. Raman spectroscopy and XRD showed the formation of the anatase phase of the TiO2. By SEM it was possible to observe several changes in the shape of the structures, by adding glycerol ball-like structures were visible, anodization time did not change the shape of the nanostructures. However, the voltage variation showed a clear control on the shape of the structures, forming nanotubes at higher voltages. It was concluded that a better control of the shape and density of the nanostructures is achieved by adding glycerol, however, in order to overcome the resistance that the electrolyte brings, higher voltages are required.
The present research was aimed to study the degradation of 2-Chlorophenol through the use of bismuth molybdate (γ-Bi2MoO6) structures supported on graphene oxide (GO) which is intended to control the recombination of charge carriers. γ-Bi2MoO6/GO systems were doped with nitrogen via chemical reaction, to reduce their energy gap, improving their photocatalytic activity. Structural and physicochemical characterization of the resulting catalysts were performed using X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and UV-Vis. The obtained compounds show good photo catalytic performance when using visible energy to degrade 2-Chlorophenol, obtaining 80% of degradation in 65 min.
Different nanostructures such as: CuOH nanorods, CuO nanosheets and Cu2O nanograins were obtained by anodization approach at room temperature during times from 10 to 40 minutes. By scanning electron microscopy technique, it was found that Cu2O nanograins were formed at 10 minutes, CuO nanosheets vertically oriented on nanograins were observed at 20 and 30 minutes, and from 20 minutes CuOH nanorods with low vertical orientation on nanosheets were formed, coexisting the three types of nanostructures at the same system. In samples without thermal treatment were observed that Raman spectra of nanograins have a typical signal at 218 cm-1 associated to Cu2O, Raman spectra of nanosheets have signals at 287 and 630 cm-1 associated to CuO and Raman spectra of nanorods, it was observed that Raman spectrum is dominated by an intense signal associated to CuOH located around 488cm-1. In addition, after 3 hours of thermal treatment at 300 °C, the morphology was conserved, and the hydrogen-related compound decreased. Raman spectra of nanorods only presented a signal at 287 cm-1 associated to CuO whereas in nanosheets three peaks at 150, 218, 304 cm-1 associated to the Cu2O were observed.
In this paper, a robust geometric navigation algorithm, designed on the special Euclidean group SE(3), of a quadrotor is proposed. The equations of motion for the quadrotor are obtained using the Newton–Euler formulation. The geometric navigation considers a guidance frame which is designed to perform autonomous flights with a convergence to the contour of the task with small normal velocity. For this purpose, a super twisting algorithm controls the nonlinear rotational and translational dynamics as a cascade structure in order to establish the fast and yet smooth tracking with the typical robustness of sliding modes. In this sense, the controller provides robustness against parameter uncertainty, disturbances, convergence to the sliding manifold in finite time, and asymptotic convergence of the trajectory tracking. The algorithm validation is presented through experimental results showing the feasibility of the proposed approach and illustrating that the tracking errors converge asymptotically to the origin.
All livestock animal species harbour complex microbial communities throughout their digestive tract that support vital biochemical processes, thus sustaining health and productivity. In part as a consequence of the strong and ancient alliance between the host and its associated microbes, the gut microbiota is also closely related to productivity traits such as feed efficiency. This phenomenon can help researchers and producers develop new and more effective microbiome-based interventions using probiotics, also known as direct-fed microbials (DFMs), in Animal Science. Here, we focus on one type of such beneficial microorganisms, the yeast Saccharomyces. Saccharomyces is one of the most widely used microorganisms as a DFM in livestock operations. Numerous studies have investigated the effects of dietary supplementation with different species, strains and doses of Saccharomyces (mostly Saccharomyces cerevisiae) on gut microbial ecology, health, nutrition and productivity traits of several livestock species. However, the possible existence of Saccharomyces which are indigenous to the animals’ digestive tract has received little attention and has never been the subject of a review. We for the first time provide a comprehensive review, with the objective of shedding light into the possible existence of indigenous Saccharomyces of the digestive tract of livestock. Saccharomyces cerevisiae is a nomadic yeast able to survive in a broad range of environments including soil, grass and silages. Therefore, it is very likely that cattle and other animals have been in direct contact with this and other types of Saccharomyces throughout their entire existence. However, to date, the majority of animal scientists seem to agree that the presence of Saccharomyces in any section of the gut only reflects dietary contamination; in other words, these are foreign organisms that are only transiently present in the gut. Importantly, this belief (i.e. that Saccharomyces come solely from the diet) is often not well grounded and does not necessarily hold for all the many other groups of microbes in the gut. In addition to summarizing the current body of literature involving Saccharomyces in the digestive tract, we discuss whether the beneficial effects associated with the consumption of Saccharomyces may be related to its foreign origin, though this concept may not necessarily satisfy the theories that have been proposed to explain probiotic efficacy in vivo. This novel review may prove useful for biomedical scientists and others wishing to improve health and productivity using Saccharomyces and other beneficial microorganisms.
Ceramic–metal composites are an important group of materials that have gained interest recently because of their peculiar properties. There have been numerous studies on the reinforcement of alumina through the incorporation of various ductile metals in it. However, these studies have been limited to determining the effect of the addition of metals on the mechanical properties of ceramics, without determining the effect of these metal additions on other physical properties of the resulting composite. In this way, in agreement with the obtained results, we have that because of the conductive nature of metals, there is a considerable decrease in the electrical resistivity of alumina, mainly when copper is added to it. However, in terms of optical performance, alumina matrix composites showed significant changes in absorbance in the visible spectra. The addition of iron, titanium, and yttrium enhanced the absorbance of alumina, whereas manganese addition significantly decreased the optical absorption.
Ternary Sn-Sb-S thin films with remarkable optical, electrical and structural properties were developed by chemical bath deposition. Tin and antimony chlorides and thioacetamide were used as tin, antimony, and sulfur ion sources, respectively, while tartaric acid was used as a complexing agent. XRD analysis of as-deposited films showed a combination of binary phases of SnS, Sn2S3, and Sb2S3, while after thermal treatment in nitrogen at 400 °C, the films became crystalline showing well-defined reflections of the ternary SnSb2S4. The heating also influenced the morphology, compactness, and thickness of the films. On the other hand, all the films showed an absorption coefficient higher than 104 cm-1, while the optical band gap of the as-deposited film decreased from 1.49 to 1.37 eV after heating at 400 °C. In addition, the photoconductivity of the films prior to heating was of 10-9 Ω-1 cm-1, while after that at 400 °C was of 10-7 Ω-1 cm-1. The evaluation of the ternary film in solar cells gave an open-circuit voltage Voc of 448 mV and short-circuit current density of Jsc of 2.4 mA/cm2.
The objective was to compare the performance of the updated Charlson comorbidity index (uCCI) and classical CCI (cCCI) in predicting 30-day mortality in patients with Staphylococcus aureus bacteraemia (SAB). All cases of SAB in patients aged ⩾14 years identified at the Microbiology Unit were included prospectively and followed. Comorbidity was evaluated using the cCCI and uCCI. Relevant variables associated with SAB-related mortality, along with cCCI or uCCI scores, were entered into multivariate logistic regression models. Global model fit, model calibration and predictive validity of each model were evaluated and compared. In total, 257 episodes of SAB in 239 patients were included (mean age 74 years; 65% were male). The mean cCCI and uCCI scores were 3.6 (standard deviation, 2.4) and 2.9 (2.3), respectively; 161 (63%) cases had cCCI score ⩾3 and 89 (35%) cases had uCCI score ⩾4. Sixty-five (25%) patients died within 30 days. The cCCI score was not related to mortality in any model, but uCCI score ⩾4 was an independent factor of 30-day mortality (odds ratio, 1.98; 95% confidence interval, 1.05–3.74). The uCCI is a more up-to-date, refined and parsimonious prognostic mortality score than the cCCI; it may thus serve better than the latter in the identification of patients with SAB with worse prognoses.
We present a fast method to prepare hybrid materials of polyaniline (PAni) with carbon nanotubes (CNTs, both undoped and nitrogen-doped) by ball milling without solvents or strong oxidants. PAni forms nanoparticles, attached to CNTs in a nanocomposite structure, with the nanotubes well dispersed among the polymer. This is achieved with only a few minutes of ball milling. Raman spectroscopy confirms that PAni was synthesized in its conductive state and suggests a good CNT–PAni interaction, particularly with nitrogen-doped CNTs. We found that water increased polymer yield, which we optimized, together with the nanocomposite conductivity, as function of amount of water and of oxidant (FeCl3). The nanocomposite conductivity is four orders of magnitude higher than that of PAni, for both types of nanotubes. Scanning electron microscopy and X-ray diffraction both show negligible damage to the CNT during this mechanosynthesis procedure, while dry milling and milling CNT in water without aniline does damage nanotubes, indicating that the reaction absorbs most of the mechanical energy.
The main objective of our study was to describe the epidemiological and microbiological features of an oligoclonal hospital-wide outbreak caused by OXA-48-producing Enterobacteriaceae (OXA-48-PE). OXA-48 is a carbapenemase belonging to Ambler class D beta-lactamases, identified frequently in the Mediterranean and Southern European countries, and associated with several Enterobacteriaceae species. An outbreak of OXA-48-PE with a complex epidemic pattern was detected in January 2011. Initial control measures included contact precautions and the reinforcement of infection control practices, but despite all efforts made, the epidemiological situation hardly changed and new measures were implemented during 2013. An observational retrospective study was performed to describe the main features of the outbreak and to analyse the cumulative incidence (CI) trends. Eight hundred and 16 patients colonised or infected by OXA-48-PE were identified during the 2-year period (January 2013–December 2014), female 46%, mean age (s.d.), 71.6 (15.2). The samples isolated in the incident cases were rectal swabs (80%), urine samples (10.7%), blood samples (2.8%) and other clinical samples (6.6%). The most frequent OXA-48-PE was Klebsiella pneumoniae. Eleven different clones were identified, but K. pneumoniae sequence types 11 and 405 were predominant: ST11 (64.2%) and ST405 (29.3%). OXA-48-PE CI trend suffered a statistically significant change in August 2013, which continued the following months. Though we could not eradicate the outbreak, we observed a statistically significant drop in CI after an intervention for OXA-48-PE control, based on patient cohort, active surveillance, electronic alerts and reinforcement of infection control measures in a tertiary hospital.
This work attempts to confirm the effect of an enriched diet with n-3 polyunsaturated fatty acids (PUFA) trying to mitigate the reproductive performances issues such as low conception rate of primiparous rabbits. A total of 127 does were fed ad libitum throughout their two first cycles with two diets with different fat sources: mixed fat in the control and salmon oil in the enriched one, with 3.19 g/100 g (n=63 does) and 28.77 g/100 g (n=64 does) of n-3 of the total fatty acid, respectively. Feed intake was similar between groups (P>0.05). Plasma progesterone concentration was higher in the enriched females than in control ones at 7 (30.9±2.18 v. 23.9±2.30 ng/ml, respectively; P=0.029) and 14 (38.7±2.18 v. 28.2±2.30 ng/ml, respectively; P=0.001) days of first gestation. Considering both cycles, reproductive parameters of mothers (fertility, duration of gestation and prolificacy) and litter parameters (weight at parturition and weaning, mortality and average daily gain (ADG) of kits during lactation) were similar in both groups. However, individual measurements of neonates of enriched group improved 5.87%, 7.10% and 18.01% (P<0.05) in terms of crown-rump length, biparietal and thoracic diameters, respectively, compared to control ones at first parturition. It is noteworthy that at the second insemination, critical point in rabbit, fertility rate of enriched group did not decline as sharply as in the control group (89.7% v. 76.6%, respectively; P=0.067), although ADG and littler weight were slightly lower at the second lactation after PUFA enrichment (P<0.05). Total PUFA and unsaturated index of milk of enriched does group were significantly elevated than in control one (33.3±0.02 v. 23.2±0.02 g/100 g and 1.20±0.00 v. 0.86±0.00, respectively; P<0.05). Finally, plasma progesterone, ovulation rate, fertility and embryo development at 3.5 days after the artificial insemination were similar between diets (P>0.05), but embryo apoptosis rate was higher in control group than in enriched one (31.1±4.56% v. 17.1±3.87%, respectively; P<0.05). In conclusion, dietary PUFA enrichment from the rearing and throughout two productive cycles improved plasma progesterone during pregnancy, fertility, milk fatty acid profile and neonates development of primiparous supporting the beneficial effect of n-3 PUFA supplementation in rabbit does.
Over the last decade, polymer composites reinforced with natural fibers gained interest, both from the academic world and from various industries. Due to the demanding needs for environmentally friendly composites, the automotive industry is now searching for biodegradable and renewable composite materials and products. There are a wide variety of different natural fibers which can be applied as reinforcement or fillers, showing potential as a replacement for inorganic fibers in automotive components. The fact that plastics are often economical to produce implies an advantage especially in very complex shapes, make them promising for obtaining composite materials, achieving short demolding times, as no chemical reaction is required. Moreover, polymers are used increasingly for stressed tribological components, whereby plastic parts replace metallic bearings, gear wheels or sliding elements. In this regard, the objective of this work was to produce composite materials based on natural fibers and to characterize the influence of the addition of different amounts of filler. To do so, composites of high-density polyethylene (HDPE) and peanut shells (PS), at different proportions (2, 4 6, 8 and 10% wt.), were prepared. The composites were produced by injection molding and molded into a particular tension test simple mold. Although the FTIR presented an increment on the O-H vibration and a band around 1600 cm-1, the HDPE structure did not present modification. The mechanical properties of the HDPE were affected with the inclusion of the fibers. The tensile performance of the HDPE decrease with the increment of the fibers inclusion whiles the elastic modulus increases. The sample with 2% of natural fibers presented the lowest wear rate (k) and coefficient of friction (µ).
A eutectoid carbon steel was studied at three different annealing heat treatment cycles: spheroidizing, isothermal annealing, and normalization (air cooling). The aim of this study was to determine the correlation among thermal, structural, and metallurgical properties, as a result of the annealing heat treatment. Microstructure differences were produced by the heat treatment cooling rate with significant effects on Vickers nanohardness, thermal properties, and crystallinity. It was reflected in photothermal radiometry (PTR) images as in thermal conductivity and diffusivity. The amplitude signal increased as the cooling rate increased. It means that as the cooling rate increased, crystallinity, thermal diffusivity, and conductivity decreased. The cooling rate affected the metallurgical structure directly, and consequently, the nanohardness which decreased due to the solid solution formation and decomposition of the pearlite phase. As the cooling rate increased, the nanohardness increased modifying structural properties and the steel crystallinity. As the cooling rate decreased, the crystallinity increased.
This work describes the electrical behavior of dye sensitized solar cells manufactured with TiO2-nanocrystalline semiconductor sensitized with diverse natural tints. A number of natural sensitizers have been tested, including red fruits as blackberries, hibiscus and beet in order to comprehend the relationship between anthocyanin and electron transfer and green vegetables as spinach and grass, as well as for known the relationship between chlorophyll and electron transfer. The nanocrystalline semiconductor was characterized by XRD, FTIR and SEM. The bands observed at 931, 667 and 514 cmˉ1 in the FTIR spectrum confirmed the presence of Ti-O-Ti bonds. From DRX analysis it is confirmed the presence of TiO2 in its anatase form. This study confirms the great potential of the use of organic dyes for sensitized the TiO2-semiconductor. Principally, in blackberries it has reached values around 300 mV owing to high concentrations of purple pigment due to the molecule called anthocyanin and the anchoring properties of the anthocyanin with the TiO2-nanocrystalline semiconductor.
The discrepancy between abundances computed using optical recombination lines (ORLs) and collisionally excited lines (CELs) is a major, unresolved problem with significant implications for the determination of chemical abundances throughout the Universe. In planetary nebulae (PNe), the most common explanation for the discrepancy is that two different gas phases coexist: a hot component with standard metallicity, and a much colder plasma enhanced in heavy elements. This dual nature is not predicted by mass loss theories, and direct observational support for it is still weak. In this work, we present our recent findings that demonstrate that the largest abundance discrepancies are associated with close binary central stars. OSIRIS-GTC tunable filter imaging of the faint O ii ORLs and MUSE-VLT deep 2D spectrophotometry confirm that O ii ORL emission is more centrally concentrated than that of [Oiii] CELs and, therefore, that the abundance discrepancy may be closely linked to binary evolution.
The objective of this study was to assess the effectiveness of a catheter-related bloodstream infection (CR BSI) reduction programme and healthcare workers' compliance with recommendations. A 3-year surveillance programme of CR BSIs in all hospital settings was implemented. As part of the programme, there was a direct observation of insertion and maintenance of central venous catheters (CVCs) to determine performance. A total of 38 education courses were held over the study period and feedback reports with the results of surveillance and recommendations were delivered to healthcare workers every 6 months. A total of 6722 short-term CVCs were inserted in 4982 patients for 58 763 catheter-days. Improvements of compliance with hand hygiene was verified at the insertion (87·1–100%, P < 0·001) and maintenance (51·1–72·1%, P = 0·029) of CVCs; and the use of chlorhexidine for skin disinfection was implemented at insertion (35·7–65·4%, P < 0·001) and maintenance (33·3–45·9%, P < 0·197) of CVCs. There were 266 CR BSI incidents recorded with an annual incidence density of 5·75/1000 catheter-days in the first year, 4·38 in the second year [rate ratio (RR) 0·76, 95% confidence interval (CI) 0·57–1·01] and 3·46 in the third year (RR 0·60, 95% CI 0·44–0·81). The education programme clearly improved compliance with recommendations for CVC handling, and was effective in reducing the burden of CR BSIs.
This article outlines the use of quenching dilatometry in phase transformation kinetics research in steels under continuous cooling conditions. For this purpose, the phase transformation behavior of a hot-rolled heat treatable steel was investigated over the cooling rate range of 0.1 to 200 °C/s. The start and finish points of the austenite transformation were identified from the dilatometric curves and then the continuous cooling transformation (CCT) diagrams were constructed. The experimental CCT diagrams were verified by microstructural characterization using scanning electron microscopy (SEM) and Vickers micro-hardness. In general, results revealed that the quenching dilatometry technique is a powerful tool for the characterization and study of solid-solid phase transformations in steels. For cooling rates between 200 and 25 °C/s the final microstructure consists on plate-like martensite with the highest hardness values. By contrast, a mixture of phases of ferrite, bainite and pearlite predominated for slower cooling rates (10-0.1 °C/s).