4,054 research outputs found
Fructosyltransferase Sources, Production, and Applications for Prebiotics Production
Fructooligosaccharides (FOS) are considered prebiotic compounds and are found in different vegetables and fruits but at low concentrations. FOS are produced by enzymatic transformation of sucrose using fructosyltransferase (FTase). Development of new production methods and search for FTase with high activity and stability for FOS production Is an actual research topic. In this article is discussed the most recent advances on FTase and its applications. Different microorganisms have been tested under various fermentation systems in order to identify and characterize new genes codifying for FTase. Some of these genes have been isolated from bacteria, fungi, and plants, with a wide range of percentages of identity but retaining the eight highly conserved motifs of the hydrolase family 32 glycoside. Therefore, this article presents an overview of the most recent advances on FTase and its applications
Voltage compensation and power factor correction in distribution networks with DVR
The stability analysis and voltage regulation in distribution systems, as well as power quality problems such as voltage sags, swells, due to connection and disconnection of large loads, short circuits and the presence of non-linear loads, require of the consideration of adequate technical solutions. In this paper, a Dynamic Voltage Restorer ( DVR ) model based on a power converter scheme for voltage compensation due to the presence of sags of amplitude since 0.1pu to 0.9pu and swells with amplitude from 1.1pu to 1.9pu, and power factor correction in distribution networks is proposed. The results are verified through MATLAB & Simulink
Ellagic acid: Biological properties and biotechnological development for production processes
Ellagic acid, 2,3,7,8-tetrahydroxy-chromeno[5,4,3-cde]chromene-5,10-dione, is a powerful bioactive compound with many potential pharmacological and industrial applications. In this review, the chemical aspects, biological properties and diverse potential applications of ellagic acid for different industries were described. This review also discussed the advance in ellagitannin biodegradation, focusing on the process of isolation of microorganisms and strain selection, medium and culture optimization, as well as fermentation systems for commercially viable industrial scale production. The performances of various fermentation techniques that have been applied for the production of ellagic acid from residual by-products were compared, while the advantages and disadvantages of each plant source were also discussed.Key words: Ellagic acid, ellagitannin, biodegradation, fungal physiology, solid-state fermentation, submerged fermentation
Cognitive impairment in Parkinson's disease without dementia
Some degree of cognitive impairment appears frequently in Parkinson's disease (PD) patients, even at the onset of the disease. However, due to the heterogeneity of the patients and the lack of standardized assessment batteries, it remains unclear which capacities are primarily affected by this disease. Fifty PD patients were assessed with 15 tests including executive functions, attention, temporal and spatial orientation, memory, and language tasks. Their results were compared with those of 42 ageâ and educationâmatched healthy seniors. Semantic fluency, along with visual search appeared to be the most discriminant tasks, followed by temporal orientation and face naming, as well as action naming and immediate recall. PD patients studied showed an impairment of frontalâ to posteriorâdependent capacities. Executive functions, attention, and recall tasks appeared to be significantly impaired in the patients. Nevertheless, significantly poor scores in tasks like action and face naming, as well as semantic fluency, also reveal a mainly semantic deficit
A model for the biochemical degradation of inosine monophosphate in hake (Merluccius merluccius)
7 påginas, 3 tablas, 3 figuras, 1 apéndiceATP-derived products are typically used as early indicators of fish quality loss during storage. In this work, we explore different biochemical routes that are potentially relevant in contributing to nucleotide degradation in hake (Merluccius merluccius). A major motivation of this study is to get more insight on the biochemical degradation mechanisms of nucleotide catabolites in hake muscle at fish storage and transport conditions. This requires the identification of its relevant pathways.
To that purpose, different degradation routes proposed in the literature are considered and a mathematical model for the degradation process is derived. First order kinetics are assumed for all the reactions and temperature dependence is taken into account through the Arrhenius equation. Unknown model parameters, namely activation energies and pre-exponential Arrhenius coefficients, are estimated via fitting to experimental data. From the estimation results, relevant routes are identified. The kinetic study is performed on sterile fish juice to avoid coupling with microbial degradation mechanisms or possible interferences of the food matrix that might hide biochemical interactions.
The proposed scheme adequately describes biochemical changes in nucleotide catabolites under variable temperature profiles. It also reveals a pathway which at least seems relevant for nucleotide degradation in hakeThe authors acknowledge financial support from the Spanish Ministry of Science and Innovation (Projects ISFORQUALITY AGL2012-39951-C02-01, PIE 201230E042 and RESISTANCE DPI2014-54085-JIN)Peer reviewe
Nonadiabatic charged spherical evolution in the postquasistatic approximation
We apply the postquasistatic approximation, an iterative method for the
evolution of self-gravitating spheres of matter, to study the evolution of
dissipative and electrically charged distributions in General Relativity. We
evolve nonadiabatic distributions assuming an equation of state that accounts
for the anisotropy induced by the electric charge. Dissipation is described by
streaming out or diffusion approximations. We match the interior solution, in
noncomoving coordinates, with the Vaidya-Reissner-Nordstr\"om exterior
solution. Two models are considered: i) a Schwarzschild-like shell in the
diffusion limit; ii) a Schwarzschild-like interior in the free streaming limit.
These toy models tell us something about the nature of the dissipative and
electrically charged collapse. Diffusion stabilizes the gravitational collapse
producing a spherical shell whose contraction is halted in a short
characteristic hydrodynamic time. The streaming out radiation provides a more
efficient mechanism for emission of energy, redistributing the electric charge
on the whole sphere, while the distribution collapses indefinitely with a
longer hydrodynamic time scale.Comment: 11 pages, 16 Figures. Accepted for publication in Phys Rev
Nationwide outbreak of Salmonella enterica serotype Kedougou infection in infants linked to infant formula milk, Spain, 2008
On 5 August 2008, the National Reference Laboratory of Salmonella (NRLS) noted an increase in the number of isolates of Salmonella enterica serotype Kedougou. As of 22 August, 29 isolates have been reported during 2008, which is ten times more than the average number of isolates identified by the NRLS during 2002-2007. All isolates have a typical, indistinguishable Pulse Field pattern (SALKEDXB-1, Spanish code) and are fully sensitive to the standard suite of antimicrobials.S
Concerns regarding the proposal for an ecological equation of state: an assessment starting from the organic biophysics of ecosystems (OBEC).
The goal of testing the theoretical fruitfulness and empirical utility of the links between ecology and thermodynamics has been elusive. This could explain the breakdown of ecology into multiple branches, some of them intended to develop models in agreement with the principles of physics. The maximum entropy algorithm (MaxEnt) is one of the most frequently mentioned topics in this field. Within the MaxEnt framework, a quantitative relationship between various ecological parameters has recently been proposed as a seeming ecological equation of state (EESH; Harte et al. 2022. An equation of state unifies diversity, productivity, abundance and biomass. Commun. Biol. 5: 874). We analyze the EESH from the interdisciplinary perspective of Organic Biophysics of Ecosystems (OBEC). Consistent with this analysis, the EESH neglects the analytical similarity between key ecological variables and statistical mechanical variables, it does not include any intensive variable useful to determine the distance of ecological systems from equilibrium, it does not involve any constant useful to define the statistical range within which the system can be considered out of danger despite widespread effects of anthropogenic impact, and its general structure bears no resemblance to previous equations of state because it is based on a subjective approach devoid of physical content that is only useful as a tool for statistical inference. So, our conclusions are: (i) the EESH does not withstand comparison with prior knowledge and empirical evidence from both ecology and physics, and (ii) it cannot be considered an ecological equation of state
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