Adaptive arrival cost update for improving Moving Horizon Estimation performance

Moving horizon estimation is an efficient technique to estimate states and parameters of constrained dynamical systems. It relies on the solution of a finite horizon optimization problem to compute the estimates, providing a natural framework to handle bounds and constraints on estimates, noises and parameters. However, the approximation of the arrival cost and its updating mechanism are an active research topic. The arrival cost is very important because it provides a mean to incorporate information from previous measurements to the current estimates and it is difficult to estimate its true value. In this work, we exploit the features of adaptive estimation methods to update the parameters of the arrival cost. We show that, having a better approximation of the arrival cost, the size of the optimization problem can be significantly reduced guaranteeing the stability and convergence of the estimates. These properties are illustrated through simulation studies.

Curcumin-Mediated Photodynamic Inactivation of Norovirus Surrogates

Photodynamic inactivation (PDI) is extensively used to inactivate different type of pathogens through the use of photosensitizers (PS). Curcumin has been identified as an excellent natural photosensitizer with some potential applications in the food industry. The aim of this study was to assess the antiviral activity of photoactivated curcumin on norovirus surrogates, feline calicivirus (FCV), and murine norovirus (MNV). Initially, different concentrations of curcumin (13.5-1358 µM) were individually mixed with each virus at titers of ca. 6-7 log TCID₅₀/ml and photoactivated by LED blue light with light dose of 3 J/cm². Results showed that photoactivated curcumin at 50 µg/mL reduced FCV titers by almost 5 log after incubation at 37 °C for 30 min. Lower antiviral activity (0.73 log TCID₅₀/mL reduction) was reported for MNV. At room temperature, curcumin at 5 µg/mL reduced FCV titers by 1.75 log TCID₅₀/mL. These results represent a step forward in improving food safety using photoactivated curcumin as an alternative natural additive to reduce viral contamination.

Efficacy of Cinnamaldehyde Against Enteric Viruses and Its Activity After Incorporation Into Biodegradable Multilayer Systems of Interest in Food Packaging

Cinnamaldehyde (CNMA), an organic compound that gives cinnamon its flavor and odor, was investigated for its virucidal activity on norovirus surrogates, murine norovirus (MNV) and feline calicivirus (FCV), and hepatitis A virus (HAV). Initially, different concentrations of CNMA (0.1, 0.5 and 1 %) were individually mixed with each virus at titers of ca. 6-7 log10 TCID50/ml and incubated 2 h at 4 and 37 °C. CNMA was effective in reducing the titers of norovirus surrogates in a dose-dependent manner after 2 h at 37 °C, while HAV titers were reduced by 1 log10 after treatment with 1 % of CNMA. When incubation time was extended, HAV titers were reduced by 3.4 and 2.7 log10 after overnight incubation at 37 °C with 1 and 0.5 % of CNMA, respectively. Moreover, this paper analyzed, for the first time, the antiviral activity of adding an active electrospun interlayer based on zein and CNMA to a polyhydroxybutyrate packaging material (PHB) in a multilayer form. Biodegradable multilayer systems prepared with 2.60 mg/cm(2) (~9.7 %) of CNMA completely inactivated FCV according to ISO 22196:2011, while MNV titers were reduced by 2.75 log10. When the developed multilayer films were evaluated after one month of preparation or at 25 °C, the antiviral activity was reduced as compared to freshly prepared multilayer films evaluated at 37 °C. The results show the excellent potential of this system for food contact applications as well as for active packaging technologies in order to maintain or extend food quality and safety.

Iterated non-linear model predictive control based on tubes and contractive constraints

This paper presents a predictive control algorithm for non-linear systems based on successive linearizations of the non-linear dynamic around a given trajectory. A linear time varying model is obtained and the non-convex constrained optimization problem is transformed into a sequence of locally convex ones. The robustness of the proposed algorithm is addressed adding a convex contractive constraint. To account for linearization errors and to obtain more accurate results an inner iteration loop is added to the algorithm. A simple methodology to obtain an outer bounding-tube for state trajectories is also presented. The convergence of the iterative process and the stability of the closed-loop system are analyzed. The simulation results show the effectiveness of the proposed algorithm in controlling a quadcopter type unmanned aerial vehicle.

Evaluation of viability PCR performance for assessing norovirus infectivity in fresh-cut vegetables and irrigation water

Norovirus (NoV) detection in food and water is mainly carried out by quantitative RT-PCR (RT-qPCR). The inability to differentiate between infectious and inactivated viruses and the resulting overestimation of viral targets is considered a major disadvantage of RT-qPCR. Initially, conventional photoactivatable dyes (i.e. propidium monoazide, PMA and ethidium monoazide, EMA) and newly developed ones (i.e. PMAxx and PEMAX) were evaluated for the discrimination between infectious and thermally inactivated NoV genogroup I (GI) and II (GII) suspensions. Results showed that PMAxx was the best photoactivatable dye to assess NoV infectivity. This procedure was further optimized in artificially inoculated lettuce. Pretreatment with 50μM PMAxx and 0.5% Triton X-100 (Triton) for 10min reduced the signal of thermally inactivated NoV by ca. 1.8 logs for both genogroups in lettuce concentrates. Additionally, this pretreatment reduced the signal of thermally inactivated NoV GI between 1.4 and 1.9 logs in spinach and romaine and lamb's lettuces and by >2 logs for NoV GII in romaine and lamb's lettuce samples. Moreover this pretreatment was satisfactorily applied to naturally-contaminated water samples with NoV GI and GII. Based on the obtained results this pretreatment has the potential to be integrated in routine diagnoses to improve the interpretation of positive NoV results obtained by RT-qPCR.

Non-covalent stacking interactions directing the structural and photophysical features of mono- and dinuclear cyclometalated palladium(ii) complexes

Cyclometallated Pd(ii) complexes with different stackings show emission in solid state in relationship to them.

Kinetics of Cr(III) and Cr(VI) removal from water by two floating macrophytes

The aim of this work was to compare Cr(III) and Cr(VI) removal kinetics from water by Pistia stratiotes and Salvinia herzogii. The accumulation in plant tissues and the effects of both Cr forms on plant growth were also evaluated. Plants were exposed to 2 and 6 mg L(-1) of Cr(III) or Cr(VI) during 30 days. At the end of the experiment, Cr(VI) removal percentages were significantly lower than those obtained for Cr(III) for both macrophytes. Cr(III) removal kinetics involved a fast and a slow component. The fast component was primarily responsible for Cr(III) removal while Cr(VI) removal kinetics involved only a slow process. Cr accumulated principally in the roots. In the Cr(VI) treatments a higher translocation from roots to aerial parts than in Cr(III) treatments was observed. Both macrophytes demonstrated a high ability to remove Cr(III) but not Cr(VI). Cr(III) inhibited the growth at the highest studied concentration of both macrophytes while Cr(VI) caused senescence. These results have important implications in the use of constructed wetlands for secondary industrial wastewater treatment. Common primary treatments of effluents containing Cr(VI) consists in its reduction to Cr(III). Cr(III) concentrations in these effluents are normally below the highest studied concentrations in this work.

Clinical outcomes in a cohort of Colombian patients with rheumatoid arthritis treated with Etanar, a new biologic type rhTNFR:Fc

OBJECTIVES

To evaluate the clinical response at 12 month in a cohort of patients with rheumatoid arthritis treated with Etanar (rhTNFR:Fc), and to register the occurrence of adverse effects.

METHODS

This is a multicentre observational cohort study. It included patients over 18 years of age with an active rheumatoid arthritis diagnosis for which the treating physician had begun a treatment scheme of 25 mg of subcutaneous etanercept (Etanar ® 25 mg: biologic type rhTNFR:Fc), twice per week. Follow-up was done during 12 months, with assessments at weeks 12, 24, 36 and 48. Evaluated outcomes included tender joint count, swollen joint count, ACR20, ACR50, ACR70, HAQ and DAS28.

RESULTS

One-hundred and five (105) subjects were entered into the cohort. The median of tender and swollen joint count, ranged from 19 and 14, respectively at onset to 1 at the 12th month. By month 12, 90.5% of the subjects reached ACR20, 86% ACR50, and 65% ACR70. The median of DAS28 went from 4.7 to 2, and the median HAQ went from 1.3 to 0.2. The rate of adverse effects was 14 for every 100 persons per year. No serious adverse effects were reported. The most frequent were pruritus (5 cases), and rhinitis (3 cases).

CONCLUSIONS

After a year of following up a patient cohort treated with etanercept 25 mg twice per week, significant clinical results were observed, resulting in adequate disease control in a high percentage of patients with an adequate level of safety.

Application of viability PCR to discriminate the infectivity of hepatitis A virus in food samples

Transmitted through the fecal-oral route, the hepatitis A virus (HAV) is acquired primarily through close personal contact and foodborne transmission. HAV detection in food is mainly carried out by quantitative RT-PCR (RT-qPCR). The discrimination of infectious and inactivated viruses remains a key obstacle when using RT-qPCR to quantify enteric viruses in food samples. Initially, viability dyes, propidium monoazide (PMA) and ethidium monoazide (EMA), were evaluated for the detection and quantification of infectious HAV in lettuce wash water. Results showed that PMA combined with 0.5% Triton X-100 (Triton) was the best pretreatment to assess HAV infectivity and completely eliminated the signal of thermally inactivated HAV in lettuce wash water. This procedure was further evaluated in artificially inoculated foods (at concentrations of ca. 6×10(4), 6×10(3) and 6×10(2)TCID50) including lettuce, parsley, spinach, cockles and coquina clams. The PMA-0.5% Triton pretreatment reduced the signal of thermally inactivated HAV between 0.5 and 2 logs, in lettuce and spinach concentrates. Moreover, this pretreatment reduced the signal of inactivated HAV by more than 1.5 logs, in parsley and ten-fold diluted shellfish samples inoculated at the lowest concentration. Overall, this pretreatment (50 μM PMA-0.5% Triton) significantly reduced the detection of thermally inactivated HAV, depending on the initial virus concentration and the food matrix.

Evaluation of Natural Compounds of Plant Origin for Inactivation of Enteric Viruses

Essential oils (EOs) and some of their main compounds have demonstrated extensive antimicrobial activity in a wide range of food spoilage or pathogenic fungi, yeast and bacteria. The aim of this study was to assess the antiviral activity of Zataria multiflora Boiss. (zataria) and Origanum vulgare (oregano) EOs on hepatitis A virus (HAV) and the effect of thymol, an active compound of Thymus vulgaris and oregano, on norovirus surrogates, feline calicivirus (FCV) and murine norovirus (MNV), and HAV. Initially, each virus at titers of ca. 6 log TCID50/ml was exposed to different concentrations of natural compounds and incubated for 2 h at 37 °C. Treatment with oregano and zataria EOs resulted in slight reductions on HAV infectivity with a maximum reduction of less than 0.5 log TCID50/ml at 0.1 % zataria EO. Thymol was effective in reducing the titers of norovirus surrogates in a dose-dependent manner. Concentrations of thymol at 0.5 and 1 % reduced FCV titers to undetectable levels, while for MNV, thymol at concentrations of 1 and 2 % resulted in reductions of 1.66 and 2.45 log TCID50/ml, respectively. However, for HAV, no effect was observed at any of the concentrations tested. These results improve the knowledge about the antiviral activity of EO and their compounds and their potential in food sanitation.

The effect of carvacrol on enteric viruses

Carvacrol, a monoterpenic phenol, is said to have extensive antimicrobial activity in a wide range of food spoilage or pathogenic fungi, yeast and bacteria. The aim of this study was to assess its antiviral activity on norovirus surrogates, feline calicivirus (FCV), murine norovirus (MNV), and hepatitis A virus (HAV), as well as its potential in food applications. Initially, different concentrations of carvacrol (0.25, 0.5, 1%) were individually mixed with each virus at titers of ca. 6-7 log TCID50/ml and incubated 2h at 37°C. Carvacrol at 0.5% completely inactivated the two norovirus surrogates, whereas 1% concentration was required to achieve ca. 1 log reduction of HAV. In lettuce wash water, carvacrol efficacy on MNV was dependent on the chemical oxygen demand (COD), with no effect over 300 ppm. A 4 log reduction in FCV infectivity was observed when 0.5% carvacrol was used to sanitize lettuce wash water, regardless of COD. Carvacrol was also evaluated as a natural disinfectant of produce, showing 1% carvacrol reduced inoculated NoV surrogates titers in lettuce by 1 log after 30 min contact. These results represent a step forward in improving food safety by using carvacrol as an alternative natural additive to reduce viral contamination in the fresh vegetable industry.

Nitrogen deposition in Spain: modeled patterns and threatened habitats within the Natura 2000 network

The Mediterranean Basin presents an extraordinary biological richness but very little information is available on the threat that air pollution, and in particular reactive nitrogen (N), can pose to biodiversity and ecosystem functioning. This study represents the first approach to assess the risk of N enrichment effects on Spanish ecosystems. The suitability of EMEP and CHIMERE air quality model systems as tools to identify those areas where effects of atmospheric N deposition could be occurring was tested. For this analysis, wet deposition of NO3(-) and NH4(+) estimated with EMEP and CHIMERE model systems were compared with measured data for the period 2005-2008 obtained from different monitoring networks in Spain. Wet N deposition was acceptably predicted by both models, showing better results for oxidized than for reduced nitrogen, particularly when using CHIMERE. Both models estimated higher wet deposition values in northern and northeastern Spain, and decreasing along a NE-SW axis. Total (wet+dry) nitrogen deposition in 2008 reached maxima values of 19.4 and 23.0 kg N ha(-1) year(-1) using EMEP and CHIMERE models respectively. Total N deposition was used to estimate the exceedance of N empirical critical loads in the Natura 2000 network. Grassland habitats proved to be the most threatened group, particularly in the northern alpine area, pointing out that biodiversity conservation in these protected areas could be endangered by N deposition. Other valuable mountain ecosystems can be also threatened, indicating the need to extend atmospheric deposition monitoring networks to higher altitudes in Spain.

Are the intertidal fish highly resistant to UV-B radiation? A study based on oxidative stress in Girella laevifrons (Kyphosidae)

Sea chub, Girella laevifrons, is a coastal fish that inhabits high intertidal rockpools along the coast of Chile. The intertidal pools where the juveniles live, are an extreme environment with high levels of ultraviolet (UV) radiation, becoming harmful to the organisms, due to oxidative stress generated by reactive oxygen species. For this reason organisms develop adaptations that allow them to survive in this complex environment. The search of biomonitor species, sensitive to UV radiation is very important in aquatic ecosystems, mainly in the southern hemisphere where depletion of the ozone layer and the consequent increase of UV radiation, have become an environmental problem. The aim of this study was to evaluate the effect of ultraviolet radiation in G. laevifrons and its possible use as UV-B radiation biomonitor specie in intertidal systems, which are very important for the Chilean fisheries. The effect of UV radiation exposure on juvenile G. laevifrons was measured through oxidative stress parameters. Catalase's activity increased with the time of exposure, unlike superoxide dismutase's activity which peaked at 2h, decreasing towards the 5th hour of irradiation. The superoxide dismutase activity in muscle tissue did not show significant differences. The lipid peroxidation and DNA damage increased in relation to exposition times. Tissue muscle's DNA damage was shown only at 5h of exposure. Significant differences between the two organs in the antioxidant capacity were observed, the liver of G. laevifrons exhibited the higher antioxidant capacity. It can be concluded that this specie exhibits effective protection mechanisms against UV radiation exposure and it is not appropriate specie as a biomonitor in intertidal systems.