Optimization of culture medium composition for manganese peroxidase and tyrosinase production during Reactive Black 5 decolourization by the yeast Trichosporon akiyoshidainum

Decolourization and degradation of the diazo dye Reactive Black 5 was carried out by the yeast Trichosporon akiyoshidainum. A nine-factor Plackett-Burman design was employed for the study and optimization of the decolourization process and production of manganese peroxidase (MnP) and tyrosinase activities. In the present study, 26 individual experiments were conducted and three responses were evaluated. Raising yeast extract concentration significantly enhanced decolourization and MnP production. Carbon and nitrogen sources, glucose and (NH4)2 SO4, showed no significant effect on any response over the concentration range tested. Other culture medium components, such as CaCl2 or MgSO4, could be excluded from the medium formula, as they had no effect on the evaluated responses. Metal ions (Fe, Cu and Mn) showed different effects on decolourization and enzymatic activities. Addition of copper significantly enhanced MnP activity and decreased dye decolourization. On the contrary, iron had a positive effect on decolourization and no effect on enzyme production. Oddly, increasing manganese concentration had a positive effect on tyrosinase production without affecting decolourization or MnP activity. These results strongly suggest that dye decolourization should be regarded as a complex multi-enzymatic process, where optimal medium composition should arise as a compromise between those optimal for each implied enzyme production.     

Addressing imperfect maintenance modelling uncertainty in unavailability and cost based optimization

Optimization of testing and maintenance activities performed in the different systems of a complex industrial plant is of great interest as the plant availability and economy strongly depend on the maintenance activities planned. Traditionally, two types of models, i.e. deterministic and probabilistic, have been considered to simulate the impact of testing and maintenance activities on equipment unavailability and the cost involved. Both models present uncertainties that are often categorized as either aleatory or epistemic uncertainties. The second group applies when there is limited knowledge on the proper model to represent a problem, and/or the values associated to the model parameters, so the results of the calculation performed with them incorporate uncertainty. This paper addresses the problem of testing and maintenance optimization based on unavailability and cost criteria and considering epistemic uncertainty in the imperfect maintenance modelling. It is framed as a multiple criteria decision making problem where unavailability and cost act as uncertain and conflicting decision criteria. A tolerance interval based approach is used to address uncertainty with regard to effectiveness parameter and imperfect maintenance model embedded within a multiple-objective genetic algorithm. A case of application for a stand-by safety related system of a nuclear power plant is presented. The results obtained in this application show the importance of considering uncertainties in the modelling of imperfect maintenance, as the optimal solutions found are associated with a large uncertainty that influences the final decision making depending on, for example, if the decision maker is risk averse or risk neutral.     

CACNA1A Mutations Causing Early Onset Ataxia: Profiling Clinical,Dysmorphic and Structural-Functional Findings

The CACNA1A gene encodes the pore-forming α_1A subunit of the voltage-gated Ca_V2.1 Ca²⁺ channel, essential in neurotransmission, especially in Purkinje cells. Mutations in CACNA1A result in great clinical heterogeneity with progressive symptoms, paroxysmal events or both. During infancy, clinical and neuroimaging findings may be unspecific, and no dysmorphic features have been reported. We present the clinical, radiological and evolutionary features of three patients with congenital ataxia, one of them carrying a new variant. We report the structural localization of variants and their expected functional consequences. There was an improvement in cerebellar syndrome over time despite a cerebellar atrophy progression, inconsistent response to acetazolamide and positive response to methylphenidate. The patients shared distinctive facial gestalt: oval face, prominent forehead, hypertelorism, downslanting palpebral fissures and narrow nasal bridge. The two α_1A affected residues are fully conserved throughout evolution and among the whole human Ca_V channel family. They contribute to the channel pore and the voltage sensor segment. According to structural data analysis and available functional characterization, they are expected to exert gain- (F1394L) and loss-of-function (R1664Q/R1669Q) effect, respectively. Among the CACNA1A-related phenotypes, our results suggest that non-progressive congenital ataxia is associated with developmental delay and dysmorphic features, constituting a recognizable syndromic neurodevelopmental disorder.     

Safety-related equipment prioritization for reliability centered maintenance purposes based on a plant specific level 1 PSA

Importance measures are widely used for multiple purposes concerning safety improvement of nuclear power plants (NPPs). This paper proposes a new approach for performing the safety-related equipment prioritization for reliability centered maintenance purposes that considers two measures of risk importance of components based on a simplified Core Damage Frequency model derived from the plant specific level 1 PSA. It is also included the case of application to the Residual Heat Removal System (RHRS) at the Confrentes NPP in Spain.     

RAMS+C informed decision-making with application to multi-objective optimization of technical specifications and maintenance using genetic algorithms

The role of technical specifications and maintenance (TSM) activities at nuclear power plants (NPP) aims to increase reliability, availability and maintainability (RAM) of Safety-Related Equipment, which, in turn, must yield to an improved level of plant safety. However, more resources (e.g. costs, task force, etc.) have to be assigned in above areas to achieve better scores in reliability, availability, maintainability and safety (RAMS). Current situation at NPP shows different programs implemented at the plant that aim to the improvement of particular TSM-related parameters where the decision-making process is based on the assessment of the impact of the change proposed on a subgroup of RAMS+C attributes.This paper briefly reviews the role of TSM and two main groups of improvement programs at NPP, which suggest the convenience of considering the approach proposed in this paper for the Integrated Multi-Criteria Decision-Making on changes to TSM-related parameters based on RAMS+C criteria as a whole, as it can be seem as a decision-making process more consistent with the role and synergic effects of TSM and the objectives and goals of current improvement programs at NPP. The case of application to the Emergency Diesel Generator system demonstrates the viability and significance of the proposed approach for the Multi-objective Optimization of TSM-related parameters using a Genetic Algorithm.     

Compatibility of plastic with phase change materials (PCM)

Even though paraffin interactions with plastics are known by industry, plastics are commonly proposed as container materials for encapsulating phase change materials (PCM) in many applications. In the literature, there are very few experimental studies of organic PCM migration in plastics and its effects on plastic properties. These interactions are a case study of environmental stress cracking, which is considered one of the most common causes of plastic failure. The aim of this work is an experimental study of interactions of some PCM typically used for thermal energy storage, and some plastic materials currently used as encapsulating materials. With the materials tested in this work, it can be concluded that, for encapsulating organic PCM, low‐density polyethylene and polypropylene showed worse behaviour than high‐density polyethylene. Copyright © 2010 John Wiley & Sons, Ltd.     

Docosahexaenoic Acid Supplementation Promotes Erythrocyte Antioxidant Defense and Reduces Protein Nitrosative Damage in Male Athletes

The aim of this study was to determine the influence of long‐term docosahexaenoic acid (DHA) dietary supplementation on the erythrocyte fatty acid profile and oxidative balance in soccer players after training and acute exercise. Fifteen volunteer male athletes (age 20.0 ± 0.5 years) were randomly assigned to a placebo group that consumed an almond‐based beverage (n = 6), or to an experimental group that consumed the same beverage enriched with DHA (n = 9) for 8 weeks. Blood samples were taken in resting conditions at the beginning and after 8 weeks of nutritional intervention and training in resting and in post‐exercise conditions. Oxidative damage markers (malonyldialdehyde, carbonyl and nitrotyrosine indexes) and the activity and protein level of antioxidant enzymes (catalase, superoxide dismutase, glutathione reductase and peroxidase) were assessed. The results showed that training increased antioxidant enzyme activities in erythrocytes. The experimental beverage increased DHA from 34.0 ± 3.6 to 43.0 ± 3.6 nmol/10⁹ erythrocytes. DHA supplementation increased the catalytic activity of superoxide dismutase from 1.48 ± 0.40 to 10.5 ± 0.35 pkat/10⁹ erythrocytes, and brought about a reduction in peroxidative damage induced by training or exercise. In conclusion, dietary supplementation with DHA changed the erythrocyte membrane composition, provided antioxidant defense and reduced protein peroxidative damage in the red blood cells of professional athletes after an 8‐week training season and acute exercise.     

Risk assessment and critical control points from the production perspective

The implementation of a risk analysis program as risk assessment and critical control points (RACCP) is most necessary in order to accomplish the foodborne industries current objective of total quality. The novelty of this technique, when compared to actual hazard analysis and critical control points (HACCP) and its extension to incorporate elements of quantitative risk analysis (QRA), is that RACCP considers the risk of the consequences produced by the production process performance deviations, both inside and outside the company, and also identifies their causative factors. On the other hand, the techniques to be taken in order to prevent or mitigate the consequences of such deviations must be consistent with the former data, but the need for a cost-benefit assessment must not be ignored so that the chosen technique be most profitable for the company. An example developed in a mineral water bottling plant showed that RACCP application is feasible and useful. During this example case, RACCP demonstrated it could obtain a profitable production process that keeps quality and safety of the final product at its maximum, while providing protection to both company and consumer.