Cloud-based architecture for web applications with load forecasting mechanism: a use case on the e-learning services of a distant university

In cloud systems, a clear necessity emerges related to the use of efficient and scalable computing resources. For this, accurate predictions on the load of computing resources are a key. Thanks to these accurate predictions, reduced power consumption and enhanced revenue of the system can be achieved, since resources can be ready when users need them and shutdown when they are no longer needed. This work presents an architecture to manage web applications based on cloud computing, which combines both local and public cloud resources. This work also presents the algorithms needed to efficiently manage such architecture. Among them, a load forecasting algorithm has been developed based on Exponential Smoothing. An use case of the e-learning services of our University presenting the behaviour of our architecture has been evaluated through a series of simulations. Among the most remarkable results, power consumption is reduced by 32 % at the cost of 367.31 US$ a month compared with the current architecture.     

Characterization of novel hyaluronic acid matrix systems for vaginal administration of metronidazole

Polymers such as Hyaluronic acid (HA), Polyethylene glycol‐400 (PEG‐400) and Xanthan Gum (XG) are promising in drug delivery applicationsbecause of their biomedical and pharmaceutical potential applications. In HA 2%‐PEG 400 systems, the effect of pH and PEG‐400 concentration were evaluated. The viscosity of HA‐PEG 400 formulations slightly increased with PEG‐400 concentration. Viscoelastic properties and shear thinning character was strongly dependent on pH. Structured systems were obtained at pH 3, with an increase of several orders of magnitude in zero‐shear viscosity values. When XG 1% structured system is added on HA (0, 0.5, and 2%) and PEG‐400 5%, a sharp increase of viscosity can be observed, obtaining a gel‐like behaviour for HA 0.5%‐XG 1%‐PEG 400 5% formulation. Finally, metronidazole release profiles in HA 2% formulations with different PEG‐400 concentrations at pH 4.5 were studied. At least 90% of metronidazole was releasedat 24 h. However, the addition of XG 1% to the HA (0.5 and 2%)‐PEG 400 5% systems delayed the drug release. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41313.     

Optical and Structural Properties of ZnO and ZnO:Cd Particles Grown by the Hydrothermal Method

Here, we examine the structural, vibrational, optical, and morphological properties of ZnO particles synthesized by the hydrothermal method, incorporating cadmium at different concentrations through the molar ratio R_m = Cd⁺²/Zn⁺² and a thermal treatment at 500°C. The X‐ray diffraction results demonstrated the high crystallinity of the ZnO compound with a wurtzite‐type hexagonal structure. The Raman scattering spectra demonstrated that the ZnO vibrational modes occur in the region between 200 and 1300 cm^?1, which is associated with different vibrational configurations characteristic of the ZnO molecule: E₂(Low), E₂(M), A₁(TO) E₁(TO), 2B₁(High), E₂(High), and TA + LO. The modes that were most affected by the incorporation of Cd²⁺ were those assigned to 2E₂(Low), E₂(M), and 2B₁(High), and this effect was associated with a greater displacement of Zn²⁺ ions. The optical study showed a reduction in the band gap and a decrease in the crystalline quality due to the substitution of Cd²⁺ in the ZnO lattice. Cadmium incorporation affected the morphology of the ZnO:Cd particles, changing the lengths and diameters of the ZnO rods; when the Cd concentration was increased, the ZnO rods shortened, forming coin‐type hexagonal structures.     

CO<Subscript>2</Subscript> adsorption at high pressures in MCM-41 and derived alkali-containing samples: the role of the textural properties and chemical affinity

The adsorption properties of N₂ and CO₂ of MCM-41 and derived alkali-containing samples were analyzed over a wide range of pressures (up to ~4500 kPa) and temperatures (between 30 and 300 °C). The high-pressure and high-temperature experiments were carried out on pure MCM-41 and K- and Na-impregnated derived samples. It was analyzed the influence of pressure and temperature on the CO₂ capture capacity on pure and impregnated samples. The adsorption performance was correlated to the structure and textural properties of the materials using X-ray diffraction and N₂ adsorption–desorption measurements. The addition of an alkaline element changes the textural properties of the material increasing the pore size, which positively affected the CO₂ adsorption capacity of these materials at high pressure. In addition, the isosteric heats of adsorption gave information about the chemical affinity between the impregnated materials and CO₂. The CO₂ adsorption at ~ 4500 kPa for the samples with 5 wt% Na at 100 and 200 °C were 77.98 and 9.79 mmol g^?1, respectively, while the pure MCM-41 adsorbs only 8.92 mmol g^?1.     

On the association between poly(vinyl alcohol) and sodium dodecyl sulfate and its effect on liquid–liquid interfacial tension: A mathematical model

Association between poly(vinyl alcohol-co-vinyl acetate) copolymer (PVA) and sodium dodecyl sulfate (SDS) was studied experimentally and theoretically. It was found that, for the ethyl acetate-aqueous phase interface in which PVA was previously adsorbed, the interfacial tension (γ) increases abruptly to a maximum and then exhibits a relatively mild decay with the addition of SDS to the aqueous phase. The theoretical results indicate that vinyl acetate (VAc) segments determine γ. However, for relatively low concentrations of SDS (C_SDS), this latter plays a major role because through its association with the VAc segments it modulates the extent to which PVA is adsorbed at the interface, indirectly determining the value of γ. As C_SDS approaches to the CMC value for SDS, its influence on γ decreases because SDS tends to self-assembly rather than associates with VAc. These model predictions are consistent with experimental findings reported in the literature.     

Analysis of bacterial community during the fermentation of pulque, a traditional Mexican alcoholic beverage, using a polyphasic approach

In this study, the characterization of the bacterial community present during the fermentation of pulque, a traditional Mexican alcoholic beverage from maguey (Agave), was determined for the first time by a polyphasic approach in which both culture and non-culture dependent methods were utilized. The work included the isolation of lactic acid bacteria (LAB), aerobic mesophiles, and 16S rDNA clone libraries from total DNA extracted from the maguey sap (aguamiel) used as substrate, after inoculation with a sample of previously produced pulque and followed by 6-h fermentation. Microbiological diversity results were correlated with fermentation process parameters such as sucrose, glucose, fructose and fermentation product concentrations. In addition, medium rheological behavior analysis and scanning electron microscopy in aguamiel and during pulque fermentation were also performed. Our results showed that both culture and non-culture dependent approaches allowed the detection of several new and previously reported species within the alpha-, gamma-Proteobacteria and Firmicutes. Bacteria diversity in aguamiel was composed by the heterofermentative Leuconostoc citreum, L. mesenteroides, L. kimchi, the gamma-Proteobacteria Erwinia rhapontici, Enterobacter spp. and Acinetobacter radioresistens. Inoculation with previously fermented pulque incorporated to the system microbiota, homofermentative lactobacilli related to Lactobacillus acidophilus, several alpha-Proteobacteria such as Zymomonas mobilis and Acetobacter malorum, other gamma-Proteobacteria and an important amount of yeasts, creating a starting metabolic diversity composed by homofermentative and heterofermentative LAB, acetic and ethanol producing microorganisms. At the end of the fermentation process, the bacterial diversity was mainly composed by the homofermentative Lactobacillus acidophilus, the heterofermentative L. mesenteroides, Lactococcus lactis subsp. lactis and the alpha-Proteobacteria A. malorum. After a 6-h fermentation, 83.27% of total sugars detected after inoculation were consumed (228.4 mM hexose equivalents) and a carbon (C) recovery of 66.18% in fermentation products was estimated. They were produced 284.4 mM C as ethanol, 71.5 mM C as acetic acid and 19 mM C as lactic acid, demonstrating the presence of homo- and heterofermentative, acetic and alcoholic metabolisms in the final product. It was also found, after hydrolysis, that the exopolysaccharide produced during the fermentation was mainly composed by fructose residues, probably inulin or levan.     

Diminution of quinolizidine alkaloids,oligosaccharides and phenolic compounds from two species of Lupinus and soybean seeds by the effect of Rhizopus oligosporus

Lupinus, like Glycine max (soybean), is an ancient leguminous plant. It has been used as a food by people living around the Mediterranean Sea and in the Andean Highlands. This legume contains quinolizidine alkaloids (Qas), oligosaccharides (OGS) and phenolic compounds (PC). The objective of this study was to evaluate the effect of the growth of Rhizopus oligosporus on the levels of Qas, OGS and PC from L. mutabilis, L. campestris and G. max through tempeh elaboration. The results showed that the soaking and cooking processes of legume seeds diminished the Qas content of L. mutabilis and L. campestris by 50%, and after 48 h of fermentation these compounds decreased by more than 90% in total. OGS diminished by more than 90% in the lupin seeds. The PC content of the three seed species subjected to these processes increased their absorbance value, probably due to the enzymatic action of a fungal tannase. These results suggested that the L. mutabilis, L. campestris and G. max fermentation with R. oligosporus is an efficient method for diminishing antinutritional factors and for obtaining a product with optimal nutritional value. Copyright © 2007 Society of Chemical Industry     

The Effect of Food Type (Fish Nuggets or French Fries) on Oil Blend Degradation during Repeated Frying

Abstract: Oil that is reused multiple times for deep frying goes through changes in chemical composition and physical characteristics, affecting the quality of the fried foods. In this study, the effect of the food type (fish nuggets or French fries) on the degradation of an oil blend during the deep‐fat frying of each food at 180°C during 12 days was determined, and the characteristics of the fried products were evaluated. The degradation of oil during repeated use was relatively faster when fish nuggets were fried than when French fries were fried, as higher values of total polar compounds were obtained. Practical Application: The results are useful for producers of French fries and fish nuggets, such as restaurants or fast foods sellers, providing them with practical guidelines within the permitted values established by the regulatory authorities. The studied foods have high economic importance and are different in their composition. Under the studied conditions, the tested oil blend may be used during 4 d (4 h per day) with a daily replenishment, without discarding the oil when frying fish nuggets, and must be discarded after 8 d when French fries are processed. This suggestion allows preparing safe fried foods for consumers.     

Application of Fast Gas Chromatography–Mass Spectrometry in Combination with the QuEChERS Method for the Determination of Pesticide Residues in Fruits and Vegetables

A fast gas chromatography–mass spectrometry method has been developed for multiresidue determination of up to 56 pesticides in fruits and vegetables in a chromatographic run time of <10 min, using a single quadrupole mass spectrometer operating in selected ion monitoring mode. The well-known acetate-buffering version of the QuEChERS method has been used for sample preparation. Programmable temperature vaporizer injection of 3 μL allowed reaching limits of detection between 0.15 and 15 μg/kg for most compounds in the sample matrices tested. The applicability of the method has been evaluated in apple, orange, carrot, and tomato. Recoveries at three fortification levels (0.01, 0.1 and 0.5 mg/kg) ranged from 70 to 120 % for most compounds, with relative standard deviations below 20 % in all cases. The developed method has been applied to fruit and vegetable samples from different Spanish provinces.