MT1‐Selective Melatonin Receptor Ligands: Synthesis,Pharmacological Evaluation,and Molecular Dynamics Investigation of N‐{[(3‐O‐Substituted)anilino]alkyl}amides

The design of compounds selective for the MT₁ melatonin receptor is still a challenging task owing to the limited knowledge of the structural features conferring selectivity for the MT₁ subtype, and only few selective compounds have been reported so far. N‐(Anilinoalkyl)amides are a versatile class of melatonin receptor ligands that include nonselective MT₁/MT₂ agonists and MT₂‐selective antagonists. We synthesized a new series of N‐(anilinoalkyl)amides bearing 3‐arylalkyloxy or 3‐alkyloxy substituents at the aniline ring, looking for new potent and MT₁‐selective ligands. To evaluate the effect of substituent size and shape on binding affinity and intrinsic activity, both flexible and conformationally constrained derivatives were prepared. The phenylbutyloxy substituent gave the best result, providing the partial agonist 4 a , which was endowed with high MT₁ binding affinity (pK_i=8.93) and 78‐fold selectivity for the MT₁ receptor. To investigate the molecular basis for agonist recognition, and to explain the role of the 3‐arylalkyloxy substituent, we built a homology model of the MT₁ receptor based on the β₂ adrenergic receptor crystal structure in its activated state. A binding mode for MT₁ agonists is proposed, as well as a hypothesis regarding the receptor structural features responsible for MT₁ selectivity of compounds with lipophilic arylalkyloxy substituents.     

Development and Validation of a Method for the Determination of Fatty Acid Methyl Ester Contents in Tung Biodiesel and Blends

The aim of this study was to develop and validate a method for the analysis of fatty acid methyl ester (FAMEs) content in tung biodiesel and blends with soybean biodiesel. The limits of detection (LOD) and quantification (LOQ), linearity, robustness, accuracy and precision were evaluated by using gas chromatography with mass spectrometry detection and impact electron ionization. The analytical curves showed correlation coefficients values higher than 0.99. The LOD and LOQ were 0.78 and 2.5 mg L⁻¹ for all FAMEs, respectively. The values of accuracy were between 86 and 117%, with relative standard deviation lower than 8%. The method was applied to tung biodiesel and tung and soybean biodiesel blends in the following proportions: 15:85, 20:80, 25:75 (%v/v). All of them showed good performance. Since the method was also applied to soybean biodiesel, the efficiency of the method for the analysis of both pure tung biodiesel and blends with different raw materials was confirmed and the robustness of the method was evidenced.     

Sketched oxide single-electron transistor

Devices that confine and process single electrons represent an important scaling limit of electronics. Such devices have been realized in a variety of materials and exhibit remarkable electronic, optical and spintronic properties. Here, we use an atomic force microscope tip to reversibly 'sketch' single-electron transistors by controlling a metal-insulator transition at the interface of two oxides. In these devices, single electrons tunnel resonantly between source and drain electrodes through a conducting oxide island with a diameter of ～1.5 nm. We demonstrate control over the number of electrons on the island using bottom- and side-gate electrodes, and observe hysteresis in electron occupation that is attributed to ferroelectricity within the oxide heterostructure. These single-electron devices may find use as ultradense non-volatile memories, nanoscale hybrid piezoelectric and charge sensors, as well as building blocks in quantum information processing and simulation platforms.     

Identification of an equivalent electrical model to a natural circulation BWR core model

In this work the developing of an electrical model of the natural circulation BWR (NCBWR) from analogies between coolant pressures drops, mass flow rates, and electrical voltages and currents, is presented. The electrical model allows estimating the coolant flows in the core, which is complex in NCBWR. The core processes (nuclear-thermo-hydraulics) are modeled with the reduced model where the reactor power is calculated from a point kinetics model with one group of delay neutrons. The reactivity due to Doppler effect, void fraction and control rod was considered. The predictions in steady state were compared with behavior of the power as a function of an ESBWR core flow, showing excellent agreement. The transient behavior considers positive reactivity due to extraction of the control rods.     

Advances in quantification and analysis of the celiac-related immunogenic potential of gluten

Gluten-free products have emerged in response to the increasing prevalence of gluten-related disorders, namely celiac disease. Therefore, the quantification of gluten in products intended for consumption by individuals who may suffer from these pathologies must be accurate and reproducible, in a way that allows their proper labeling and protects the health of consumers. Immunochemical methods have been the methods of choice for quantifying gluten, and several kits are commercially available. Nevertheless, they still face problems such as the initial extraction of gluten in complex matrices or the use of a standardized reference material to validate the results. Lately, other methodologies relying mostly on mass spectrometry-based techniques have been explored, and that may allow, in addition to quantitative analysis, the characterizationof gluten proteins. On the other hand, although the level of 20 mg/kg of gluten detected by these methods is sufficient for a product to be considered gluten-free, its immunogenic potential for celiac patients has not been clinically validated. In this sense, in vitro and in vivo models, such as the organoid technology applied in gut-on-chip devices and the transgenic humanized mouse models, respectively, are being developed for investigating both the gluten-induced pathogenesis and the treatment of celiac disease. Due to the ubiquitous nature of gluten in the food industry, as well as the increased prevalence of gluten-related disorders, here we intend to summarize the available methods for gluten quantification in food matrices and for the evaluation of its immunogenic potential concerning the development of novel therapies for celiac disease to highlight active research and discuss knowledge gaps and current challenges in this field.     

High prevalence of antimicrobial‐resistant Escherichia coli from animals at slaughter: a food safety risk

BACKGROUND: There has been concern about the increase of antimicrobial resistant bacteria and protection of animal and public health, along with food safety. In the present study, we evaluate the incidence of antimicrobial resistance among 192 strains of Escherichia coli isolated from faecal samples of healthy food‐producing animals at slaughter in Portugal. RESULTS: Ninety‐seven % of the pig isolates, 74% from sheep and 55% from cattle were resistant to one or more antimicrobial agents, with the resistances to ampicillin, streptomycin, tetracycline and trimethoprim–sulfamethoxazole the most common phenotype detected. Genes encoding resistance to antimicrobial agents were detected in most of the resistant isolates. Ninety‐three % of the resistant isolates were included in the A or B1 phylogenetic groups, and the virulence gene fimA (alone or in association with papC or aer genes) was detected in 137 of the resistant isolates. Five isolates from pigs belonging to phylogroup B2 and D were resistant to five different antimicrobial agents. CONCLUSION: Our data shows a high percentage of antibiotic resistance in E. coli isolates from food animals, and raises important questions in the potential impact of antibiotic use in animals and the possible transmission of resistant bacteria to humans through the food chain. © 2012 Society of Chemical Industry     

Life cycle cost analysis of energy efficiency design options for refrigerators in Brazil

The purpose of this paper was to present the results of a life cycle cost analysis concerning the purchase and operation of a more efficient popular refrigerator model compared with a baseline design in Brazil. The summarized results may be useful for organizations working to promote sustainable energy development. This paper specifically focuses on refrigerators, since their energy consumption is predicted to constitute over 30% of the total average domestic electricity bill in Brazilian households. If all new Brazilian refrigerators had an energy efficiency at the level consistent with the least life cycle cost of ownership, it would result in an annual savings of 2.8 billion dollars (US$) in electricity bills, 45 TWh of electricity demand, and 18 Mt of CO₂ emissions, with a respective payback period of 7 years which is less than half the average estimated lifetime of a refrigerator. The analysis was conducted following the guidelines of similar analyses available from the US Department of Energy and the Collaborative Labeling and Appliance Standards Program.

Integrated waste-to-energy conversion and waste transportation within island communities

Usually in islands both primary energy sources and drinking water are missing. Additionally, municipal solid waste (MSW) must be managed avoiding exclusive use of landfills, which limits sustainable development. Power generation from MSW incineration contributes significantly to replacing energy produced from fossil fuels and to reduce overall emissions. A solution based on thermodynamics, environmental and economic analyses and 3D-GIS modelling for the afore-mentioned problems for Cape Verde is proposed. This model integrates waste transportation optimisation and incineration with energy recovery combining production of heat and power (CHP), the heat being used for drinking water production. The results show that extraction condensing steam turbines are more suitable when power production is a priority (5.0 MW with 4000 m³/d of drinking water), whereas back-pressure turbines yield 5540–6650 m³/d of drinking water with an additional power production of 3.3–4.7 MW. The environmental and economic assessment performed shows the feasibility of the proposed CHP solution, which brings a considerable reduction in net air emissions (1.6 kt), including a significant decrease in the greenhouse gas emissions (131 ktCO₂), and that the revenue from energy sales (€15 million) has potential to balance the incineration cost. Moreover, when terrain relief is accounted for in the route optimisation for minimum fuel consumption, savings up to 11% are obtained.     

Effect of rotor–tower interaction,tilt angle,and yaw misalignment on the aeroelasticity of a large horizontal axis wind turbine with composite blades

This paper presents a detailed analysis of the rotor–tower interaction and the effects of the rotor's tilt angle and yaw misalignment on a large horizontal axis wind turbine. A high‐fidelity aeroelastic model is employed, coupling computational fluid dynamics (CFD) and structural mechanics (CSM). The wind velocity stratification induced by the atmospheric boundary layer (ABL) is modeled. On the CSM side, the complex composite structure of each blade is accurately modeled using shell elements. The rotor–tower interaction is analyzed by comparing results of a rotor‐only simulation and a full‐machine simulation, observing a sudden drop in loads, deformations, and power production of each blade, when passing in front of the tower. Subsequently, a tilt angle is introduced on the rotor, and its effect on blade displacements, loads, and performance is studied, representing a novelty with respect to the available literature. The tilt angle leads to a different contribution of gravity to the blade deformations, sensibly affecting the stresses in the composite material. Lastly, a yaw misalignment is introduced with respect to the incoming wind, and the resulting changes in the blade solicitations are analyzed. In particular, a reduction of the blade axial displacement amplitude during each revolution is observed.     

Comparison of acid and amyloglucosidase hydrolysis for estimation of non‐structural polysaccharides in feed samples

Enzymatic methods (amyloglucosidase) and methods based on acid solutions (0.1, 0.2 and 0.3 M H₂SO₄ for 1, 2 and 3 h at 100 °C) for the hydrolysis of non‐structural carbohydrates from different feed samples were compared. The monomeric units resulting from the enzymatic and acid hydrolysis were determined by the glucose oxidase and reducing sugar methods. There was a significant effect of acid concentration and of time of hydrolysis on the glucose and reducing sugar values in the hydrolysate. Glucose values were similar for both the amyloglucosidase method and the most intense conditions of hydrolysis (0.3 M for 3 h) for some samples. Under these conditions, however, the reducing sugar values were higher. No acid hydrolysis method was found to estimate correctly the total non‐structural carbohydrates, but α‐linked glucose polymers in biological samples may be determined by sample hydrolysis with a 0.3 M H₂SO₄ solution for 3 h at 100 °C since the glucose in the hydrolysate is determined by the glucose oxidase method and the sucrose content of the sample is negligible. © 1999 Society of Chemical Industry