Coreflood assay using extremophile microorganisms for recovery of heavy oil in Mexican oil fields

A considerable portion of oil reserves in Mexico corresponds to heavy oils. This feature makes it more difficult to recover the remaining oil in the reservoir after extraction with conventional techniques. Microbial enhanced oil recovery (MEOR) has been considered as a promising technique to further increase oil recovery, but its application has been developed mainly with light oils; therefore, more research is required for heavy oil. In this study, the recovery of Mexican heavy oil (11.1°API and viscosity 32,906?mPa?s) in a coreflood experiment was evaluated using the extremophile mixed culture A7, which was isolated from a Mexican oil field. Culture A7 includes fermentative, thermophilic, and anaerobic microorganisms. The experiments included waterflooding and MEOR stages, and were carried out under reservoir conditions (70°C and 9.65?MPa). MEOR consisted of injections of nutrients and microorganisms followed by confinement periods. In the MEOR stages, the mixed culture A7 produced surface-active agents (surface tension reduction 27?mN?m(-1)), solvents (ethanol, 1738?mg?L(-1)), acids (693?mg?L(-1)), and gases, and also degraded heavy hydrocarbon fractions in an extreme environment. The interactions of these metabolites with the oil, as well as the bioconversion of heavy oil fractions to lighter fractions (increased alkanes in the C(8)-C(30) range), were the mechanisms responsible for the mobility and recovery of heavy oil from the porous media. Oil recovery by MEOR was 19.48% of the residual oil in the core after waterflooding. These results show that MEOR is a potential alternative to heavy oil recovery in Mexican oil fields.     

Effect of lysozyme on "flor" velum yeasts in the biological aging of sherry wines

Biological aging is a key step in the production of Sherry wine classified as “fine”. During this stage, a film of yeast referred to as “flor velum” covers the surface of the wine and substantially alters its characteristics. Other microorganisms may coexist with flor yeasts, such as lactic acid bacteria and non-Saccharomyces yeasts, whose growth may be favored under certain conditions, causing organoleptic deviations and deterioration of the wine. To prevent the development of lactic bacteria, lysozyme usage has been introduced. Lysozyme is a hydrolytic enzyme with muramidase activity that can lyse gram-positive bacteria; its use in winemaking was approved by the OIV in 1997 (resolution OENO 10/97). Thus far, the use of lysozyme during the production of Sherry wines is not widespread despite its effectiveness in controlling lactic acid bacteria. However, there have been no studies on the effect of lysozyme on flor velum. The aim of this study was to determine the influence of lysozyme on yeast growth and the formation, development and metabolism of flor velum during the biological aging process of Sherry wine. The results indicate that lysozyme does not affect the flor yeast during the fermentative stage or biofilm stage. However, if yeast inoculation is carried out under submerged culture conditions during biological aging, low doses of lysozyme (≥12.5 g/hL) affect cell multiplication and the membrane hydrophobicity of the yeast, inhibiting their aggregation and flotation and the subsequent development of flor velum. Thus, the yeast inoculation protocol and the methodology used for the addition of lysozyme influence velum development, its metabolism and the wine characteristics.     

Prevalence of malnutrition in minors under 5 years of age in Tabasco

AIMS: Abdominal aortic aneurysms are characterised by changes in the extracellular matrix of the arterial media, in particular a reduction in elastin concentration. These changes are mediated by increased levels of endogenous matrix metalloproteinases (MMPs). Recently, calcium channel blockers have been shown to increase the proteolytic activity of MMP-2 secreted by vascular smooth muscle cells. It may therefore by hypothesised that calcium antagonists may potentiate the activity of MMPs in aneurysmal disease and thus accelerate AAA expansion. In this study, the ability of amlodipine--a calcium antagonist--to influence elastin degradation, was assessed in a previously described model of aneurysmal disease. METHODS: Porcine aortic segments (n = 8) were pre-incubated in exogenous pancreatic elastase for 24 h prior to culture in standard conditions for 6 days with 10 and 100 micrograms/l amlodipine. Control segments were cultured both with and without amlodipine and without elastase. At the termination of culture MMPs were extracted from the tissue and quantified by a combination of substrate gel enzymography and immunoblotting. The volume fractions of elastin and collagen were determined by stereological analysis of EVG stained sections. RESULTS: Gel enzymography demonstrated significantly increased MMP-9 activity in the amlodipine treated segments, median 4.218 vs. 2.809 arbitrary units (p < 0.01) and this elevated activity was reflected in a significant destruction of medial elastin 27.0 vs. 40.5% (p < 0.05). CONCLUSION: Therapeutic ranges of amlodipine significantly enhanced elastin degradation and potentiated MMP-9 activity within the aortic organ cultures.     

Effect of interparticle interaction on the low temperature oxidation of CO over size-selected Au nanocatalysts supported on ultrathin TiC films

This work aims to get insight into the influence of interparticle interactions on catalysis. The low temperature CO oxidation is used as a model reaction. A strong dependence of the catalytic activity and stability of gold nanoparticles uniformly dispersed on polycrystalline TiC films was observed as a function of the interparticle distance. Two samples with similar height distributions (∼2 nm), but with different average interparticle distances (∼30 and ∼80 nm), were synthesized using diblock copolymer encapsulation. Their chemical reactivity was investigated by temperature programmed desorption (TPD), and reactive coarsening and subsequent deactivation was observed for the sample with the smallest interparticle distance. The system with the largest average interparticle distance showed higher stability towards agglomeration and longer lifetime.     

“Today I Tell” A Comics and Story Creation App for People with Autism Spectrum Condition

ABSTRACT

This article describes the design, development, and evaluation of an application to help people with autism spectrum condition (ASC) express themselves through the creation of stories and comics. The intended platform of the application is touchscreen devices. The design process follows a human-centered design approach involving caregivers, teachers, usability experts, primary school students, and people with ASC. The characteristics considered are explained to design and implement the application, as well as the different evaluation steps. The prototype design was evaluated with 36 experts (teachers, caregivers, and usability experts). Next, 14 primary school students and 10 participants from a special education institution tested the application. Among all the participants, five students of the primary school institution have attention-deficit hyperactivity disorder and five students of the special education institution had ASC. The feedback gathered shows the importance of multidisciplinary teams in developing an application aimed at people with special needs. Non-functional features such as usability and accessibility can be bypassed by developers and this is the point at which teachers, caregivers, usability experts, and even the end users of the application can provide their insights in order to improve the product during its development phase. This also reduces the costs that would be incurred if the final product had to be changed after its development.     

Characterization of a p‐nitrophenol‐degrading mixed culture with an improved methodology of fluorescence in situ hybridization and confocal laser scanning microscopy

BACKGROUND: Confocal laser scanning microscopy (CLSM) provides critical information of the presence of autofluorescence signals inherent to the samples under study, which may interfere with probe fluorescence. Therefore, it is important to determine the emission spectrum of the biomass autofluorescence under study in order to avoid, as much as possible, this wavelength range when selecting specific probe emissions and to modify, if necessary, the original fluorescence in situ hybridization (FISH) protocol in order to enhance probes signals. RESULTS: Microbial characterization of a p‐nitrophenol‐degrading activated sludge through a conventional FISH protocol was not possible because the fluorescence signal of the unlabelled cells was similar to or even higher than the signal emitted by hybridized cells, impeding the separation of the two signals and therefore, preventing biomass characterization. An optimized but simple FISH approach was developed in order to ease observation of the p‐nitrophenol‐degrading bacteria studied in this work. The final results allowed identification of Arthrobacter sp. (Micrococcaceae family) and genus Acinetobacter (Moraxellaceae family) in the p‐nitrophenol‐degrading activated sludge, whereas no hybridization was found for Pseudomonas spp. CONCLUSIONS: The hypothesis of a mixed culture following, at the same time, different degradation pathways has been confirmed through the microbial characterization of enriched p‐nitrophenol‐degrading activated sludge. Copyright © 2011 Society of Chemical Industry     

$${ SIM}^2{ RRAM}$$: a physical model for RRAM devices simulation

In the last few years, resistive random access memory (RRAM) has been proposed as one of the most promising candidates to overcome the current Flash technology in the market of non-volatile memories. These devices have the ability to change their resistance state in a reversible and controlled way applying an external voltage. In this way, the resulting high- and low-resistance states allow the electrical representation of the binary states “0” and “1” without storing charge. Many physical models have been developed with the aim of understanding the mechanisms that control the resistive switching. In this work, we have compiled the main theories accepted as well as their corresponding models for the conduction characteristics. In addition, simulation tools play a very important role in the task of checking these theories and understanding these mechanisms. For this reason, the simulation tool called \(\hbox {SIM}^{2}\hbox {RRAM}\) has been presented. This simulator is capable of replicating the global behavior of RRAM cell based on \(\hbox {HfO}_{x}\).     

Metal-free electrocatalysts obtained from agave waste by solar pyrolysis for oxygen reduction reaction

Characterization and electrochemical evaluation of novel metal-free electrocatalysts obtained by solar pyrolysis is reported. Carbon-based electrocatalysts were prepared from agave bagasse waste, using a sustainable process based on concentrated solar energy as heat source. Agave was processed in a spherical borosilicate glass solar reactor using a heating rate of 30 °C min^?1 to a target of 500, 700, or 900 °C, and maintaining temperature for 1 h under inert atmosphere. The structure and composition of the prepared electrocatalysts were influenced by pyrolysis temperature. In addition, electrocatalytic activity towards the oxygen reduction reaction in 0.1 M KOH solution was explored. The electrocatalyst obtained at 500 °C showed the highest activity among all pyrolyzed samples due to its moderate surface area, but mostly due to its higher oxygen content. The metal-free electrocatalysts reported in this work are promising eco-friendly alternative as cathode materials for anion-exchange membrane fuel cells. This study provides a sustainable approach to use agricultural biomass waste to produce valuable materials for electrochemical energy devices.