Diosgenin quantification,characterisation and chemical composition in a tuber collection of Dioscorea spp. in the state of Jalisco,Mexico

Dioscorea spp. tubers are known commonly as camote de cerro to the state of Jalisco, México. Besides its use as food, it contains diosgenin, a raw material used widely for synthesising steroid hormones. The purpose of the present research was to determine diosgenin contents by gas chromatography‐mass spectrometry (GC‐MS), as well as physical and chemical characteristics of sixty Dioscorea spp. accessions cultivated in mesh shade coming from eleven localities in the state of Jalisco. Extraction protocol for diosgenin was maceration combined with ethanol 80%. Significant statistical differences for diosgenin content were found between accessions, finding levels between 0.02 and 0.16 mg kg^?1 in dry basis. Length, weight tuber, proportion pulp/skin, percentage of pulp and percentage of skin showed significant differences. Chemical composition based in fresh weight presented in moisture percentage a range of 71.93–83.26%, crude protein 1.42–1.74%, ashes 0.80–1.16%, lipid 0.13–0.17%, crude fibre 3.80–4.02% and total carbohydrates 13.97–25.44%. Results show that tubers from Jalisco can be an important source of nutrients for consumers.     

Effects of postharvest UV‐C treatment on carotenoids and phenolic compounds of vine‐ripe tomatoes

Light red tomatoes were exposed to different doses of ultraviolet C (UV‐C) irradiation (1.0, 3.0 and 12.2 kJ m^?2). After treatment, the tomatoes were stored for 2 days at room temperature, and then analysed to determine the effect of irradiation on the main antioxidants, carotenoids and phenolic compounds and the results compared with the control samples. The lycopene content was found to have increased by 14% with respect to the control samples, while β‐carotene decreased. Cis‐isomers from lycopene also increased when the tomatoes were exposed to irradiation for more than 3 h. UV‐C irradiation also had a positive effect on total phenolic compounds; however, the same effect was not observed in the individually analysed phenolic compounds. While chlorogenic and ferulic acids increased in content, naringenin and rutin contents decreased. These results suggest that UV‐C irradiation of tomatoes could improve the beneficial effect of red tomatoes for human health by increasing the levels of certain bioactive compounds; it could also be used to obtain higher content of bioavailability components, such as cis‐isomers from lycopene.     

Identification of Sialylated Oligosaccharides Derived from Ovine and Caprine Caseinomacropeptide by Graphitized Carbon Liquid Chromatography–Electrospray Ionization Ion Trap Tandem Mass Spectrometry

Isolation and characterization of oligosaccharides from caseinomacropeptide (CMP) are important in understanding the biological and functional properties of CMP. However, it is difficult to achieve this goal, due to the high degree of isomerism present in these types of compounds. In this study, the sialylated oligosaccharides derived from ovine and caprine CMP were released as oligosaccharide alditols by reductive β-elimination and subsequently separated and characterized using graphite carbon column liquid chromatography–negative electrospray ionization ion trap tandem mass spectrometry (LC/ESI(?)-MSⁿ). Although, the chromatographic resolution of isomeric oligosaccharides was not achieved perfectly, the characteristic tandem mass spectra of these compounds allowed differentiating and confirming unequivocally the structure of each one of the oligosaccharides. In CMP of both species, four trisaccharides and four tetrasaccharides were identified as O-glycans. Their chemical structures were identified to be Galβ1-3(NeuAcα2-6)GalNAcol, NeuAcα2-3Galβ1-3GalNAcol, Galβ1-3(NeuGcα2-6)GalNAcol, NeuGcα2-3Galβ1-3GalNAcol, NeuAcα2-3Galβ1-3(NeuGcα2-6)GalNAcol, NeuGcα2-3Galβ1-3(NeuAcα2-6)GalNAcol, NeuAcα2-3Galβ1-3(NeuAcα2-6)GalNAcol, and NeuGcα2-3Galβ1-3(NeuGcα2-6)GalNAcol. The LC/MSⁿ methodology using an ion trap-type mass analyzer shown in this study is of general applicability for determination of short O-glycan oligosaccharides.     

Dynamic estimations of metabolic fluxes with constraint-based models and possibility theory

Living cells can be modelled by successively imposing known constraints that limit their behaviour, such as mass balances, thermodynamic laws or enzyme capacities. The resulting constraint-based models enclose all the functional states that the modelled cells may exhibit. Then, predictions can be obtained from the models in two main ways: adding experimental data to determine the state of cells at given conditions (MFA) or invoking an assumption of evolved optimal behaviour (FBA). Both MFA and FBA predictions are typically performed at steady state. However, it is easy to take extracellular dynamics into account. This work explores the benefits of using possibility theory to get these dynamic predictions. It will be shown that the possibilistic methods (a) provide rich estimates for time-varying fluxes and metabolite concentrations, (b) account for uncertainty and data scarcity, and (c) give predictions relaxing the optimality assumption of FBA. On the other hand, these methods could serve as basis for monitoring and fault detection systems in industrial bioprocesses.     

Nonlinear PI control of fed-batch processes for growth rate regulation

This paper deals with the regulation of the biomass specific growth rate, which is an important goal in many fed-batch fermentation processes. The proposed control system is based on the minimal model paradigm, requiring only biomass and volume measurement along with some bounds on the reaction rate. The controller has the structure of a partial state feed-back with adjustable gain. An integral-proportional control algorithm is designed to adjust this gain. It is inspired in concepts of invariant control and system immersion. First, a nonlinear integral action that makes invariant a goal manifold defined by a reference model dynamics is developed. Then, a proportional output error feed-back is incorporated to the control law with the aim of fastening convergence. Stability is investigated in detail using Lyapunov functions. To implement the control law, an estimation of the growth rate is required like any other PI-like controller. Because of its strong convergence properties, a sliding observer that requires the same process information as the controller is used for this task, although conventional continuous observers can alternatively be used provided they are fast enough to preserve stability. Simulation results showing the transient response and robustness features of the controller under nominal and perturbed scenarios are presented.     

Computational evolutionary inverse lagrangian puff model

This article presents a model based on the principles of evolutionary computation and on the principles of dispersion of an Inverse lagrangian puff model of the type Backward gaussian puff tracking in order to determine the spatial behavior over time of the concentration for PM_2.5 and PM₁₀ in a study area.     

An 8-Bit Digitally Controlled Programmable Phase Shifter Circuit for Sinusoidal Signals with 252∘ Phase Control Range

In this paper, the synthesis, design, and implementation of a programmable phase shifter circuit for sinusoidal signals is presented. The proposed circuit, built-up herein with operational amplifiers (OPAMPs), high precision resistors and low voltage switches, consists of a digitally controlled amplitude attenuator in combination with a single-tone orthogonalizer. Experimental results agree with theoretical background: the attained phase range was 252^° in 256 steps with a median step of 0.9^°. The inaccuracy of the circuit was determined to be of 0.03 %. Contrary to other OPAMP approaches for sinusoidal signals reported in the literature and based on a first-order all-pass filter structure, the approximation suggested in this work is based on a different concept. The achieved results demonstrate the functionality of the system for the case of a sinusoidal signal with frequency of 1 kHz. Notwithstanding, the proposed architecture can be extended to operate at higher frequencies by using different building blocks with larger bandwidth. Furthermore, it can be extended as well to work out with other periodic input waveforms, like triangular shapes or square waves, with the use of an appropriate orthogonalizer.     

Constructing a unifying theory of dynamic programming DCOP algorithms via the generalized distributive law

In this paper we propose a novel message-passing algorithm, the so-called Action-GDL, as an extension to the generalized distributive law (GDL) to efficiently solve DCOPs. Action-GDL provides a unifying perspective of several dynamic programming DCOP algorithms that are based on GDL, such as DPOP and DCPOP algorithms. We empirically show how Action-GDL using a novel distributed post-processing heuristic can outperform DCPOP, and by extension DPOP, even when the latter uses the best arrangement provided by multiple state-of-the-art heuristics.     

Analysis of Arizona's Water Resources System

An analysis of Arizona's water resources system has been implemented. This study uses a qualitative system analysis approach to evaluate the most important components of the system: water supply, water demand, laws and regulations, stakeholders, decision makers, etc. Moreover, the investigation centres on some key components of the water resources system such as water conservation in active management areas (AMA), rural Arizona, population growth, and water rights transfers. This study provides insights on these important components, identifies factors that can be enhanced and offers suggestions for improving them. The overall goal of this analysis is to contribute ideas that will help to establish a more efficient and holistic programme to secure sustainable development of water resources.