Cyclic oligo(butylene 2,5-furandicarboxylate) and e-caprolactone were copolymerized in bulk at 130-150 °C by enzymatic ring opening polymerization using CALB as catalyst. Copolyesters within a wide range of compositions were thus synthesized with weight-average molecular weights between 20,000 and 50,000, the highest values being obtained for equimolar or nearly equimolar contents in the two components. The copolyesters consisted of a blocky distribution of the e-oxycaproate (CL) and butylene furanoate (BF) units that could be further randomized by heating treatment. The thermal stability of these copolyesters was comparable to those of the parent homopolyesters (PBF and PCL), and they all showed crystallinity in more or less degree depending on composition. Their melting and glass-transition temperatures were ranging between those of PBF and PCL with values increasing almost linearly with the content in BF units. The ability of these copolyesters for crystallizing from the melt was evaluated by comparative isothermal crystallization and found to be favored by the presence of flexible e-oxycaproate blocks. These copolyesters are essentially insensitive to hydrolysis in neutral aqueous medium but they became noticeably degraded by lipases in an extend that increased with the content in CL units.
Hosseini Asl, S.; Ghadi, A.; Sharifzadeh Baei, M.; Javadian, H.; Maghsudi, M.; Kazemian, H. Fuel (Guildford) Vol. 217, p. 320-342 DOI: 10.1016/j.fuel.2017.12.111 Data de publicació: 2018-04-01 Article en revista
Safarpoor, M.; Ghaedi, M.; Asfaram, A.; Yousefi, M.; Javadian, H.; Zare, H. Ultrasonics sonochemistry Vol. 42, p. 76-83 DOI: 10.1016/j.ultsonch.2017.11.001 Data de publicació: 2018-04-01 Article en revista
Lopes, M.; Triguero, J.; Torras, J.; Perpète, Eric A.; Michaux, Catherine Anne Gisèle; Aleman, C.; Zanuy, D. Biophysical chemistry Vol. 234, p. 6 DOI: 10.1016/j.bpc.2017.12.003 Data de publicació: 2018-03-01 Article en revista
Bahrani, S.; Ghaedi, M.; Ostovan, A.; Javadian, H.; Khoshnood Mansoorkhani, M.; Taghipour, T. Journal of pharmaceutical and biomedical analysis Vol. 149, p. 166-171 DOI: 10.1016/j.jpba.2017.10.040 Data de publicació: 2018-02-05 Article en revista
In this research, a facile and selective method was described to extract L-cysteine (L-Cys), an essential a-amino acid for anti-ageing playing an important role in human health, from human blood plasma sample. The importance of this research was the mild and time-consuming synthesis of zinc organic polymer (Zn-MOP) as an adsorbent and evaluation of its ability for efficient enrichment of L-Cys by ultrasound-assisted dispersive micro solid-phase extraction (UA-DMSPE) method. The structure of Zn-MOP was investigated by FT-IR, XRD and SEM. Analysis of variance (ANOVA) was applied for the experimental data to reach the best optimum conditions. The quantification of L-Cys was carried out by high performance liquid chromatography with UV detection set at ¿ = 230 nm. The calibration graph showed reasonable linear responses towards L-Cys concentrations in the range of 4.0–1000 µg/L (r2 = 0.999) with low limit of detection (0.76 µg/L, S/N = 3) and RSD = 2.18 (n = 3). The results revealed the applicability and high performance of this novel strategy in detecting trace L-Cys by Zn-MOP in complicated matrices.
The contact of the coolant with the fuel pin during irradiation produces a gradient of temperature in the fuel pellet that segregates the radionuclides (RN) depending on its volatility and reactivity. This segregation determines the Instant Release Fraction (IRF), an important source of radiological risk in the performance assessment (PA) of a Deep Geologic Repository (DGR). RN segregation was studied radially in previous papers. In the present work, it was studied axially, taking into special consideration the cutting position of the solid sample to be studied. Iodine and caesium were the RN with the highest release, while the contribution of rubidium, strontium, molybdenum and technetium to the IRF depended on their chemical state. The interpellet presence (known also as dishing) effect was clearly observed for caesium, increasing its release by one order of magnitude. According to these results, one of the major contributions to the IRF comes from the RN trapped in the dishing and has to be considered in the sampling and data interpretation that will be performed for the PA of the DGR.
Morales, J.; Martinez de Ilarduya, A.; Muñoz, S. Journal of polymer science. Part A, polymer chemistry Vol. 56, num. 3, p. 290-299 DOI: 10.1002/pola.28895 Data de publicació: 2018-02-01 Article en revista
Cyclic oligo(butylene 2,5-furandicarboxylate) and e-caprolactone were copolymerized in bulk at 130-150 ºC by enzymatic ring opening polymerization using CALB as catalyst. Copolyesters within a wide range of compositions were thus synthesized with weight-average molecular weights between 20,000 and 50,000, the highest values being obtained for equimolar or nearly equimolar contents in the two components. The copolyesters consisted of a blocky distribution of the e-oxycaproate (CL) and butylene furanoate (BF) units that could be further randomized by heating treatment. The thermal stability of these copolyesters was comparable to those of the parent homopolyesters (PBF and PCL), and they all showed crystallinity in more or less degree depending on composition. Their melting and glass-transition temperatures were ranging between those of PBF and PCL with values increasing almost linearly with the content in BF units. The ability of these copolyesters for crystallizing from the melt was evaluated by comparative isothermal crystallization and found to be favored by the presence of flexible e-oxycaproate blocks. These copolyesters are essentially insensitive to hydrolysis in neutral aqueous medium but they became noticeably
Phosphorus (P) is a vital macronutrient required to improve the agricultural yields but its excessive use as a fertilizer has resulted in pollution of water bodies leading to eutrophication. With no reserves of phosphorus source in Spain, increased dependence on phosphorus in agriculture have not only increased dependence on imports but also has raised concerns on its future availability as a resource. A Phosphorous Flow Analysis (PFA) was conducted for Spain for the year 2012 focusing on the food production and consumption systems. The results obtained were finally compared with PFA at both country level and continent level (EU-27). To quantify food and non-food flows systems, country specific data were considered. The sectors covered were crop production (CP), animal production (AP), food processing (FP), non-food production (NF) and consumption (HC). The findings reveal that a total of 325 kt P was imported by Spain in 2012; 66% of which was accumulated in markets stock of food and feed, fertilizers and non-food (91 kt P) while 33% was lost to the environment through land-fill, losses to water bodies, land accumulation and incineration. The largest proportion of losses is associated with water bodies (44.7 kt P) followed by agriculture and land accumulation (42.1 kt P). Wastewater treatment plants (WWTPs) received around 79.5 kt P within wastewater, with 60% being removed in sewage sludge. The 31.7 kt P discharged within final effluent represented the 71% of the total losses to water bodies. Around 69% of the sewage sludge was recycled to agriculture and 27% was sent directly to landfill including the ashes from incineration. Net accumulation was 1.84 kg P/cap which was similar to values reported for the EU-27 average (2.5 kg P/cap).
Guaya, D.; Valderrama, C.; Farran, A.; Sauras, T.; Cortina, J. Science of the total environment Vol. 612, p. 728-738 DOI: 10.1016/j.scitotenv.2017.08.248 Data de publicació: 2018-01-15 Article en revista
The removal of nutrients (nitrogen (N), phosphorous (P)) from waste water has become a resource recovery option in recent regulations worldwide, as observed in the European Union. Although both of these nutrients could be recovered from the sludge line, > 70–75% of the N and P is discharged into the water line. Efforts to improve the nutrient recovery ratios have focused on developing low-cost technologies that use sorption processes. In this study, a natural zeolite (clinoptilolite type) in its potassium (K) form was impregnated with hydrated metal oxides and used to prepare natural hybrid reactive sorbents (HRS) for the simultaneous recovery of ammonium (NH4 +) and phosphate (PO4 3 -) from treated urban waste water. Three unfertile soils (e.g., one acidic and two basic) amended with N-P-K charged HRS were leached with deionized water (e.g. to simulate infiltration in the field) at two- and three-day time intervals over 15 different leaching cycles (equivalent to 15 bed volumes). The N-P-K leaching profiles for the three charged hybrid sorbents exhibited continuous nutrient release, with their values dependent on the composition of minerals in the soils. In the basic soil that is rich in illite and calcite, the release of potassium (K+) and ammonium (NH4 +) is favoured by-ion exchange with calcium (Ca2 +) and accordingly diminishes the release of phosphate (PO4 3 -) due to its limited solubility in saturated calcite solutions (pH 8 to 9). The opposite is true for sandy soils that are rich in albite (both acidic and basic), whereas the release of NH4 + and K+ was limited and the values of both ions measured in the leaching solutions were below 1 mg/L. Their leaching solutions were poor in Ca2 +, and the release of PO4 3 - was higher (up to 12 mg P-PO4 3 -/L). The nutrient releases necessary for plant growth were provided continuously and were controlled primarily by the soil mineral dissolution rates fixing the soil aqueous solution composition (e.g. pH and ionic composition; in particular, the presence of calcite is a determinant for nutrient release, especially in alkaline soils). The N-P-K charged HRS sorbents that were used for soil amendment may be an alternative for avoiding nutrient leaching and reaching the goals of soil sustainability in agriculture and reducing the nutrient overloading of surface waters.
acteria-mediated diseases are a global healthcare concern due to the development and spread of antibiotic resistant strains. Cationic compounds are considered membrane active biocidal agents having a great potential to control bacterial infections, while limiting the emergence of drug resistance. Herein, the versatile and simple Layer-by-Layer (LbL) technique was used to coat alternating multilayers of an antibacterial aminocellulose conjugate and the biocompatible hyaluronic acid on biocompatible polymer nanoparticles (NPs), taking advantage of the nano-size of these otherwise biologically inert templates. Stable polyelectrolyte-decorated particles with an average size of 50 nm and zeta potential of + 40.6 mV were developed after five LbL assembly cycles. The antibacterial activity of these NPs against the Gram-positive Staphylococcus aureus (S. aureus) and Gram-negative Escherichia coli (E. coli) increased significantly when the polycationic aminocellulose was in the outermost layer. The large number of amino groups available on the particles surface, together with the nano-size of the multilayer conjugates, improved their interaction with bacterial membrane phospholipids leading to membrane disruption, as confirmed by a Langmuir monolayer model, and the 10 logs reduction for both bacteria. The biopolymer decorated NPs were also able to inhibit the biofilm formation of S. aureus and E. coli by 94 and 40%, respectively, without affecting human cells viability. The use of LbL coated NPs appears as a promising antibiotic-free alternative for controlling bacterial infections using low amount of antimicrobial agent.
Javadian, H.; Ghasemi, M.; Ruiz, M.; Sastre, A.; Hosseini Asl, S.; Masomi, M. Ultrasonics sonochemistry Vol. 40, p. 4-68 DOI: 10.1016/j.ultsonch.2017.08.022 Data de publicació: 2018-01-01 Article en revista
In this study, NiO/Rosa Canina-L seeds activated carbon nanocomposite (NiO/ACNC) was prepared by adding dropwise NaOH solution (2 mol/L) to raise the suspension pH to around 9 at room temperature under ultrasonic irradiation (200 W) as an efficient method and characterized by FE-SEM, FTIR and N2 adsorption-desorption isotherm. The effect of different parameters such as contact time (0–120 min), initial metal ion concentration (25–200 mg/L), temperature (298, 318 and 333 K), amount of adsorbent (0.002–0.007 g) and the solution's initial pH (1–7) on the adsorption of Pb (II) was investigated in batch-scale experiments. The equilibrium data were well fitted by Langmuir model type 1 (R2 > 0.99). The maximum monolayer adsorption capacity (qm) of NiO/ACNC was 1428.57 mg/L. Thermodynamic parameters (¿G°, ¿H° and ¿S°) were also calculated. The results showed that the adsorption of Pb (II) onto NiO/ACNC was feasible, spontaneous and exothermic under studied conditions. In addition, a fuzzy-logic-based model including multiple inputs and one output was developed to predict the removal efficiency of Pb (II) from aqueous solution. Four input variables including pH, contact time (min), dosage (g) and initial concentration of Pb (II) were fuzzified using an artificial intelligence-based approach. The fuzzy subsets consisted of triangular membership functions with eight levels and a total of 26 rules in the IF-THEN approach which was implemented on a Mamdani-type of fuzzy inference system. Fuzzy data exhibited small deviation with satisfactory coefficient of determination (R2 > 0.98) that clearly proved very good performance of fuzzy-logic-based model in prediction of removal efficiency of Pb (II). It was confirmed that NiO/ACNC had a great potential as a novel adsorbent to remove Pb (II) from aqueous solution.
Vílchez, J.; Muñoz, M.; Bonilla, J.; Planas, E. Journal of loss prevention in the process industries Vol. 51, p. 169-177 DOI: 10.1016/j.jlp.2017.12.010 Data de publicació: 2018-01-01 Article en revista
This paper presents new configuration factors for a fireball located at ground level, as radiation emitting source, and a differential receiver, considering the shadow effect of a third finite area that stands between them. The configuration factors were obtained with the combination of a numerical method and a ray-tracing algorithm and are summarized in form of a practical single chart. This work contributes significantly to the knowledge of configuration factors between a sphere and a differential receiver considering the shadow effect because so far, there are no references in existing catalogs in the literature about this specific geometry. Configuration factors serve as inputs for surface-to-surface radiation transport calculations and other like. In chemical engineering, the radiant field produced by a fireball has a strong interest in consequences assessment. Current fireball models do not consider the shadow effect, overestimating vulnerability by thermal radiation and leading to greater safety distances. A case study has been performed to show the interference of a protection wall with respect to the radiation intensity received by a target.
The solvent extraction of germanium and some heavy metals by commercial tri-octyl/decyl amine (Alamine 336), N-methyl-N, N-dioctyl chloride (Aliquat 336) and phosphine oxide (Cyanex 923) has been studied. In each extraction system, germanium was only extracted from a solution containing nickel, cadmium, cobalt, and zinc, which had a composition similar to gasification coal fly ash aqueous leach solutions. Under a comparable condition, the germanium extraction efficiency by the aforementioned extractants was in the order Aliquat 336 > Alamine 336 > Cyanex 923. The slope analysis method showed that 2 moles of Alamine 336 and Aliquat 336, as well as 4 moles of Cyanex 923, participated in the extraction of germanium. In amine extraction systems, tartaric acid was required as a complexant used to convert germanium to anionic species. As a result, the ratio of 2 (mole ration of tartaric acid to Ge) was required to complete anionic complexation. On the other hand, oxalic acid with a concentration of 0.1 M was chosen as a proper solvated complexant in the Cyanex 923 system. HCl solutions with concentrations of 1 and 2 M can properly strip germanium from the loaded Alamine 336 and Aliquat 336, respectively. In addition, 0.1 M NaOH was sufficient for germanium stripping from Cyanex 923. Consequently, it can be concluded that Aliquat 336 can be an economical and industry-friendly extractant for germanium solvent extraction from a mixed solution.
Teaching is continuously evolving. After analysing the quality of student learning, potential opportunities for improvement are detected; alternative teaching methodologies are envisaged and proposed; they are tested, assessed and debugged and, eventually, changes are finally widely implemented. This process is essential in order to seek highquality learning at university level, but it can only be achieved through teacher education. However, the majority of university teachers in Spain do not receive specific training by default. Technical expertise in their fields has traditionally been all which educators are required in order to perform their job. This is one of the reasons why the portion of university teachers committed with teaching innovation stays relatively low. This communication will present the relationship existing between teacher education and teaching innovation in a very specific case. The flipped classroom methodology has recently been implemented in the Bachelor’s degree in Chemical Engineering at the Universitat Politècnica de Catalunya, as described in a separate communication to this conference. This experience, which has given successful results so far, is a direct consequence of the teacher training program promoted by the same university. The so-called “Programa de Postgrau en Ensenyament Universitari en Ciències, Tecnologia, Enginyeria i Matemàtiques” 1 (i.e. Master’s degree in Science, Technology, Engineering and Mathematics –STEM- education) is a set of courses and workshops organized by the “Institut de Ciències de l’Educació” (i.e. Institute for Education Science). It is addressed to all the university’s teaching staff and it consists in a 15 ECTS training program composed of 3 blocks: 6 ECTS of basic courses, 3 ECTS of complementary courses and 6 ECTS assigned to a final project during which the trainee must design, implement and evaluate a teaching innovation project. Subjects covered include, among others, competence-based class design, innovation and research methodologies, communication skills, social abilities required for university education, feedback techniques for the assessment of the learning quality and methodology continuous improvement. In this case, a young teaching assistant with little previous experience received the training. His final project consisted in the introduction of the flipped classroom in one unit of a second-year course: new activities were designed, all needed materials were created (including videos) and additional feedback items were introduced in order to track the effectivity of the new methodology. The project was advised by a senior teacher with a long experience in teaching innovation and the course coordinator. Collected evidence showed a very high level of satisfaction among students, who rated as very positive the impact of the methodology change in their learning. Hence the importance of providing appropriate, specific training for the university teachers. Even novice educators can achieve useful innovations if they are properly trained. Figure 1 outlines this education flow
The flipped classroom is a relatively novel teaching methodology which is gathering more and more attention in the science, technology, engineering and mathematics community. It is based on a switch of the way that learning activities have traditionally been distributed inside and outside the classroom. Its main benefits are a more customized teaching and a better accessibility to the instructor during the most critical learning stages. This implies a potential boost in the quality of the learning process and the efficiency of the teacher’s time, usually extremely limited. However, the implementation of this methodology implies the complete re-arrangement of the course structure, the design of additional activities and the preparation of new materials. While the benefits may be worth it, the transition constitutes a significant workload for the instructors, especially if they have little or no experience with this methodology. This communication presents a pilot implementation of the flipped classroom methodology in the Bachelor’s Degree in Chemical Engineering taught at the Barcelona East School of Engineering (UPC). The methodology was applied to one unit of the course of transport phenomena during the spring semester 2017. Theoretical explanations were provided to students in the form of five whiteboard animation videos distributed online through the university e-learning platform. These videos were specially created for this class using Papershow’s digital pen and Camtasia’s video editor. They were made available to students two weeks prior to the first session of the unit and they were accompanied by short multiple-choice tests with the aim of providing formative assessment. Subsequently, the three classroom sessions assigned to this unit were entirely dedicated to the discussion of doubts and practical problem resolution, mainly through collaborative activities. Feedback received from the online tests was used to revisit particular weaknesses in the assimilation of concepts. The evidence collected through online Student Evaluation of Educational Quality (SEEQ) questionnaires (Marsh, 1982) showed a very high level of satisfaction among students. Students’ judgement on the interest of the subject and the value of the learnt concepts increased about 30% after the implementation, while their acknowledged level of attention in class rose around 24% in average. Furthermore, 73.3% of the surveyed students agreed or strongly agreed that the flipped classroom methodology raised their motivation when studying the subject, and 86.7% agreed or strongly agreed that, generally speaking, the flipped classroom allowed a better learning than the traditional methodology. Moreover, students were actively involved in the process and provided valuable suggestions about potential improvements. After processing all gathered information, an improvement plan was designed and a second iteration is to be put into practice during the fall semester 2017. Given the first successful experience, now the variation in student performance will also be assessed by adding summative evaluation items to the evidence set
One of the great advantages of electrospun fibers is the large tridimensional area produced, capable of storing any type of material. The aim of our investigation is to study the electrospinning technique to produce polymer membranes for drug delivery applications, given their large surface area and ability to transport a bioactive compound. A mathematical modeling of the delivery system kinetics was also studied to find the mechanism that controls the releasing process. Results showed that electrospinning could provide regular and smooth membranes suitable for drug delivery processes. The mathematical modeling also proved that thicker PLLA membranes exhibited a Fickian diffusion behavior during the drug transport, presenting better control in drug delivery processes
Reig, M.; Vecino, X.; Valderrama, C.; Gibert, O.; Cortina, J. Separation and purification technology Vol. 195, p. 404-412 DOI: 10.1016/j.seppur.2017.12.040 Data de publicació: 2017-12-19 Article en revista
In this work, selectrodialysis (SED) was used to separate arsenic (As(V)) from copper (Cu(II)) and (Zn(II)) of acidic metallurgical process streams by integrating non-selective and selective membranes. The separation process is determined by the chemical speciation of the involved elements. In this case, As(V) is mainly present as anionic species (H2AsO4-), while Cu(II) and Zn(II) are mainly present as cationic species although partially complexed as neutral complexes (CuSO4 and ZnSO4). A lab set-up was used to conduct the experimental tests with different type of standard and mono-selective ion-exchange membranes. The results obtained showed that by SED configuration it was possible to recover around 80±0.2 % of Cu(II), 87±0.2 % of Zn(II) and 95±0.3 % of As(V) from the feed solution to the rich-product streams with an energy consumption of 2.6±0.2 kWh/kg CuSO4+ZnSO4. Furthermore, a Cu/Zn-rich stream with a purity of both divalent cations of 99.8 % (0.02 % of As(V)) was achieved by means of SED. Overall, the results herein gathered suggest that SED is an efficient separation technology for Cu(II) and Zn(II) recovery from mining and metallurgical acidic streams.
En aquesta tesis, nous homooligopèptids derivats de fenilalanina ha estat sintetitzats per tal d'estudiar la seva capacitat d'autoorganització i examinar la influencia de l'estructura química i les condicions externes. Encara que les interaccions NH3+···-OOC cap-a-cua en els homopèptids desprotegits mostren estabilitzar les estructures peptídiques, s'han introduït funcionalitzacions químiques a través de la incorporació de proteccions a N- i C-, com per exemple, grups bloquejadors aromàtics, grups d'acoblament azida-alquí, l'anió trifluoroacetat o un bloc de polilàctide.Diferents capítols estan dedicats a mostrar que la llargada del bloc d'homopèptid també juga un paper rellevant en l'organització supramolecular dels derivats de fenilalanina.Els resultats publicats evidencien no només el control que exerceixen les característiques de l'ambient sinó també del substrat. Les interaccions pèptid··· pèptid, pèptid···superfície i la rugositat superficial han estat assenyalades com a factors clau que defineixen la forma, les dimensions i l'estabilitat de les estructures jerarquitzades.
Two series of aliphatic-aromatic copolyesters derived from succinic and 2,5-furandicarboxylic acids, and di-O-2-(hydroxyethyl) resorcinol as diol substituent of either 1,4-butanediol or ethylene glycol, respectively, were obtained by ring opening polymerization(ROP) performed in bulk and catalyzed by Sn(Oct)2. Cyclic oligomers of furandicarboxylate of di-O-2-(hydroxyethyl) resorcinol were successfully synthesized by high-dilution condensation, and then copolymerized with cyclic oligomers of either butylene or ethylene succinate. The synthesized resorcinol-containing succinate-furanoatecopolyesters had Mw oscillating between 50,000 and 30,000 g·mol-1 depending on composition, and they all displayed a nearly random microstructure. They showed an excellent thermal stability with onset decomposition temperatures near 300 °C. They are amorphous with Tg increasing monotonically with the content in resorcinol in both series with values ranging from -30 or -13 °C for butylene and ethylene-based copolyesters, respectively, up to around 45 °C. The resorcinol-containing succinate-furanoate copolyesters showed appreciable hydrolytic degradation when incubated for a few weeks in water under physiological conditions, a behavior that was notably enhanced in the presence of lipases
Tryptophan 7-halogenase catalyzes chlorination of free tryptophan to 7-chlorotryptophan, which is the first step in the antibiotic pyrrolnitrin biosynthesis. Many biologically and pharmaceutically active natural products contain chlorine and thus, an understanding of the mechanism of its introduction into organic molecules is important. Whilst enzyme-catalyzed chlorination is accomplished with ease, it remains a difficult task for the chemists. Therefore, utilizing enzymes in the synthesis of chlorinated organic compounds is important, and providing atomistic mechanistic insights about the reaction mechanism of tryptophan 7-halogenase is vital and timely. In this work, we examined a mechanism for the reaction of tryptophan chlorination, performed by tryptophan 7-halogenase, by calculating potential energy and free energy surfaces using two different Combined Quantum Mechanical/Molecular Mechanical (QM/MM) methods both employing Density Functional Theory (DFT) for the QM region. Both computational strategies agree on the nature of the rate-limiting step and provided close results for the reaction barriers of the two reaction steps. The calculations for both the potential energy and the free energy profiles showed very similar geometric features and hydrogen bonding interactions for the characterized stationary points.
The RPAR peptide, a prototype C-end Rule (CendR) sequence that binds to neuropilin-1 (NRP-1), has potential therapeutic uses as internalization trigger in anticancer nanodevices. Recently, the functionalization of gold nanoparticles with CendR peptides has been proved to be a successful strategy to target the NRP-1 receptor in prostate cancer cells. In this work, we investigate the influence of two gold surface facets, (100) and (111), on the conformational preferences of RPAR using molecular dynamics simulations. Both clustering and conformational analyses revealed that the peptide backbone becomes very rigid upon adsorption onto gold, which is a very fast and favored process, the only flexibility being attributed to the side chains of the two Arg residues. Thus, the different components of RPAR tend to adopt an elongated shape, which is characterized by the pseudo-extended conformation of both the backbone and the Arg side chains. This conformation is very different from the already known bioactive conformation, indicating that RPAR is drastically affected by the substrate. Interestingly, the preferred conformations of the peptide adsorbed onto gold facets are not stabilized by salt bridges and/or specific intramolecular hydrogen bonds, which represent an important difference with respect to the conformations found in other environments (e.g. the peptide in solution and interacting with NRP-1 receptor). However, the conformational changes induced by the substrate are not detrimental for the use of gold nanoparticles as appropriate vehicles for the transport and targeted delivery of the RPAR. Thus, once their high affinity for the NRP-1 receptor induces the targeted delivery of the elongated peptide molecules from the gold nanoparticles, the lack of intramolecular interactions facilitates their evolution towards the bioactive conformation, increasing the therapeutic efficacy of the peptide.
En este siglo, el mayor empleo que se les ha dado a los polímeros sintéticos ha sido como sustitutos de materiales más tradicionales, en particular, materiales para envase y embalaje. Hoy en día la industria de envasado es, por mucho, la mayor consumidora de plásticos. Otra aplicación interesante de estos materiales son los sistemas de administración de fármacos. Los polímeros han jugado un papel fundamental la tecnología de administración de fármacos al proporcionar un medio de liberación controlada de agentes terapéuticos en dosis constantes durante largos periodos; la dosificación cíclica y la liberación sintonizable de fármacos hidrofílicos e hidrofóbicos. Actualmente, los avances modernos en la administración de fármacos se basan en el diseño racional de polímeros para la liberación de dosis controladas que modifican distintas funciones biológicas de forma específica. Los poliésteres alifáticos tales como el poli(ácido L-láctico), el poli(succinato de butileno) y los polihidroxialcanoatos, entre otros, constituyen ejemplos primarios de polímeros de base biológica que se distinguen por ser completamente renovables y presentar biodegradabilidad parcial o total.Este trabajo de doctorado está dedicado a la síntesis de poliésteres alifáticos al azar y de bloques a partir de recursos renovables con aplicación para el envasado y la administración de fármacos. El objetivo principal de este proyecto es desarrollar nuevos polímeros biológicos con propiedades similares o incluso mejores en comparación a los plásticos convencionales obtenidos a partir de fuentes norenovables.Los dos acetales cíclicos, 2,3-di-O-metileno-L-treitol y dimetil 2,3-di-O-metileno-L-trearato, se usaron para la síntesis de dos series de copoliésteres de PBS que difieren en qué unidad, butileno o succinato, se reemplazó, además de los homopoliésteres originales correspondientes. Se usó 2,4:3,5-di-O-metileno-D-glucitol para la síntesis de copoliésteres de PBS mediante policondensación en estado fundido. Se sintetizaron tres series de polialcanoatos (adipatos, suberatos y sebacatos) usando como monómeros tres dioles bicíclicos base azúcar derivados de D-glucosa y D-manosa. Los copoliésteres tribloques ABA se sintetizaron mediante ROP de L-láctido en solución iniciada por macroiniciadores de poliester telequelico basados en D-glucosa y L-tartárico.Los poliésteres sintetizados se caracterizaron por espectroscopia de resonancia magnética nuclear (RMN), cromatografía de permeación en gel (GPC) y viscosimetría. Las propiedades térmicas se analizaron mediante calorimetría de barrido diferencial (DCS) y termogravimetría (TGA). La estructura cristalina de los poliésteres se estudió mediante rayos X y sus propiedades mecánicas también se evaluaron. La degradación hidrolítica y los ensayos de biodegradación fueron seguidos por GPC y NMR. Las nanopartículas hechas de copoliésteres tribloque se caracterizaron por microscopía electrónica de barrido (SEM) y dispersión de luz dinámica (DLS).
Pastor, E.; Oiveras M., I.; Urquiaga-Flores, E.; Quintano, J.; Manta, M.I.; Planas, E. International journal of wildland fire Vol. 26, num. 12, p. 1040-1052 DOI: 10.1071/WF17033 Data de publicació: 2017-12-08 Article en revista
Smouldering ground fires have severe environmental implications. Their main effects are the release of large amounts of carbon to the atmosphere with loses of organic soil and its biota. Quantitative data on the behaviour of smouldering wildfires are very scarce and are needed to understand its ecological effects, to validate fuel consumption and smouldering propagation models and to develop danger-rating systems. We present, for the first time, a methodology for conducting smouldering experiments in field conditions. This method provides key data to investigate smouldering combustion dynamics, acquire fire behaviour metrics and obtain indicators for ecological effects of smouldering fires. It is to be applied in all types of undisturbed soils. The experimental protocol is based on a non-electric ignition source and the monitoring system relies on combining both point and surface specific temperature measurements. The methodology has been developed and applied by means of large series of replicate experiments in highly organic soils at the forest–grassland treeline of the Peruvian Andes. The soil tested exhibited weak ignition conditions. However, transition to oxidation phase was observed, with smouldering combustion during 9¿h at 15-cm depth and residence times at temperatures above dehydration of ~22¿h.
An optimization framework is presented to support the model builder in elucidating compartmental models that plausibly describe data obtained during experimentation. Here, one specifies a priori the maximum number of compartments and type of flows to contemplate during the optimization. The mathematical model follows a ‘superstructure’ approach, which inherently considers the different feasible flows between any pair of compartments. The model activates those flows/compartments that provide the optimal fit for a given set of experimental data. A regularized log-likelihood function is formulated as the performance metric. To deal with the resulting set of differential equations orthogonal collocation on finite elements is employed. A case study related to pharmacokinetics of an oncological agent demonstrates the advantages and limitations of the proposed approach. Numerical results show that the proposed approach can provide 33% smaller mean square prediction error in comparison with a compartmental model previously suggested in the literature.
López, P.; Pérez-Rodríguez, I.; Estrany, F.; Devesa, R. Journal of water supply research and technology (AQUA) Vol. 66, num. 8, p. 598-605 DOI: 10.2166/aqua.2017.183 Data de publicació: 2017-12-01 Article en revista
The role of sulfate and nitrate in the taste of drinking water is not entirely clear. Taste threshold concentrations (TTCs) were estimated for these two species by the 3-AFC method by a trained panel, as sodium and calcium salts. In both cases TTCs for nitrate were about 100 mg NO3/L, twice the usual reference value of international recommendations. TTCs for sulfate were about 160 mg SO4/L (sodium salt) and 80 mg SO4/L (calcium); 75% detection values were also estimated for both anions. An experiment with a series of duo-trio tests plus preference showed that sulfate at low concentrations tended to improve the taste of water. However, at high concentrations it was perceived negatively: salty and bitter were the main descriptors used. The reversion concentration took place between 176 and 259 mg SO4/L. These results indicate that nitrate has to be considered an important issue for health, but with no relevant role in the taste of water. Sulfate shows a positive influence at moderate concentrations but becomes negative at high levels. The usual aesthetic-based level of 250 mg/L established by international regulations appears to be reasonable. The findings of this study with trained panellists are preliminary. Future research with consumer panels is recommended.
A study of the solvent extraction process of Nd(III) from chloride solutions has been carried out using an ionic liquid (AliOle) prepared from Aliquat 336 (Methyl-tri(octyl/decyl)ammonium chloride) and Oleic Acid. The IL was chosen among other homemade ionic liquids and commercial extractants due to its high Nd(III) extraction ability and good phase separation. Increasing AliOle concentration improves the extraction of Nd(III) as expected. The pH of the aqueous phase strongly influences the extraction process. The appropriate equilibrium pH region has been established in the range 5–6.5. The effect of chloride concentration in the aqueous phase has been investigated. High concentrations of Cl- anion contribute to increasing the extraction yield by promoting neodymium(III) speciation in the aqueous phase. Two extraction models are proposed from experimental data. Chloride concentration in the aqueous phase determines the Nd(III) extraction mechanism. The models consider extraction of Nd3 + species when chloride concentration in the solution is low and NdCl2 + species when chloride concentration is high. Competitive extraction between HCl and the metal ions is also included in the models. They are able to reproduce feasibly the experimental Nd(III) extraction extension.
Properties related with the charge storage capacity have been evaluated for three-layered films made with two sheets of poly(3,4-ethylenedioxythiophene) separated by a sheet of poly(N-methylpyrrole) or poly(3,4-ethylenedioxythiophene-co-N-methylpyrrole) (3l-PEDOT/PNMPy or 3l-PEDOT/P(EDOT-co-NMPy), respectively). The most distinctive trend of the copolymer, which shows electrochemical properties intermediate between those of the two homopolymers, is the formation of a biphasic structure, EDOT- and NMPy-rich blocks organizing separately. The ability to exchange charge reversibly is higher for 3l-PEDOT/P(EDOT-co-NMPy) than for 3l-PEDOT/PNMPy, the electroactivity and electrostability of such two 3-layered films being significantly better than that of single-layered PEDOT. Advantages of 3l-PEDOT/P(EDOT-co-NMPy) are mainly based on the nanophase-segregated structure of the copolymer. Thus, the intermediate layer can be considered as random disposition of ultrathin dielectrics having nanometric length and width. In terms of charge storage, the intermediate layer of 3l-PEDOT/P(EDOT-co-NMPy) can be viewed as a thin reservoir filled of heterogeneously distributed nanometric supercapacitors that are connected in series among them and in parallel to the PEDOT layers. The superiority of 3l-PEDOT/P(EDOT-co-NMPy) as organic electrochemical supercapacitor compared to other 3-layered systems, has been proved by powering a red LED bulb.
Dietary flavonoids exhibit many biologically-relevant functions and can potentially have beneficial effects in the treatment of pathological conditions. In spite of its well known antioxidant properties, scarce structural information is available on the interaction of flavonoids with membrane receptors. Advances in the structural biology of a specific class of membrane receptors, the G protein-coupled receptors, have significantly increased our understanding of drug action and paved the way for developing improved therapeutic approaches. We have analyzed the effect of the flavonoid quercetin on the conformation, stability and function of the G protein-coupled receptor rhodopsin, and the G90V mutant associated with the retinal degenerative disease retinitis pigmentosa. By using a combination of experimental and computational methods, we suggest that quercetin can act as an allosteric modulator of opsin regenerated with 9-cis-retinal and more importantly, that this binding has a positive effect on the stability and conformational properties of the G90V mutant associated with retinitis pigmentosa. These results open new possibilities to use quercetin and other flavonoids, in combination with specific retinoids like 9-cis-retinal, for the treatment of retinal degeneration associated with retinitis pigmentosa. Moreover, the use of flavonoids as allosteric modulators may also be applicable to other members of the G protein-coupled receptors superfamily.
A continuous adsorption was used for removal of azure II (AZ II) and auramine O (AO) from aqueous solutions using Pinus eldarica stalks activated carbon (PES-AC) from aqueous solutions. The effects of initial dye concentration, flow rate, bed height and contact time on removal percentage of AO and AZ II were evaluated and optimized by central composite design (CCD) at optimum pH = 7.0. ZnO nanoparticles loaded on activated carbon were also used to remove AO and AZ II at pH = 7.0 and other optimum conditions. The breakthrough curves were obtained at different flow rates, initial dye concentrations and bed heights and the experimental data were fitted by Thomas, Adams–Bohart and Yoon–Nelson models. The main parameters of fixed-bed column including its adsorption capacity at breakthrough point (qb), adsorption capacity at saturation point (qs), mass transfer zone (MTZ), total removal percentage (R%), and empty bed contact time (EBCT) were calculated. The removal percentages calculated for AZ II and AO II were in the range of 51.6–61.1% and 40.6–61.6%, respectively. Bed adsorption capacity (N0) and critical bed depth (Z0) were obtained by BDST model.
Lähde, A.; Chimentao, R.; Karhunen, T.; Alvarez , M.; Llorca, J.; Medina, F.; Jokiniemi, J.; Modesto, L. Advanced powder technology Vol. 28, num. 12, p. 3296-3306 DOI: 10.1016/j.apt.2017.10.009 Data de publicació: 2017-12 Article en revista
The catalytic properties of Co-Al spinel nanoparticles prepared by liquid-feed flame spray pyrolysis (L-F FSP) were investigated in the glycerol conversion in gas phase in an atmosphere of hydrogen. Reduction at 1123¿K of the as-synthesized spinel nanoparticles induced the formation a new phase containing metallic cobalt species. Although, the reducibility of cobalt oxides is greatly decreased due to interaction with aluminium species, this strong interaction may prevent the aggregation of Co particles under the harsh reduction conditions. X-ray photoelectron spectroscopy (XPS) of the reduced spinel nanoparticles at 1123¿K revealed that the Co/Al atomic ratio has decreased to Co/Al¿=¿0.11, which may indicate a redistribution of the aluminum and cobalt species at the surface of the sample submitted to the reduction in a flow of hydrogen at 1123¿K. X-ray diffraction (XRD) and high resolution electron microscopy (HRTEM) also reinforced the formation of metallic cobalt species after reduction of cobalt from the spinel nanoparticles at 1123¿K. The main products obtained from the conversion of glycerol in the gas phase were hydroxyacetone, pyruvaldehyde, lactic acid and lactide. FSP ensured uniform dispersion of the active metal on a support material.
González, N.; Custal, M.A.; Tomara, G.; Psarras, G.; Riba, J.; Armelin, E. European polymer journal Vol. 97, p. 57-67 DOI: 10.1016/j.eurpolymj.2017.10.001 Data de publicació: 2017-12 Article en revista
Natural rubber (NR) nanocomposites have been prepared with hydroxylated barium titanate filler (BaTiO3-OH), employing emulsion polymerization followed by vulcanization process. The addition of barium titanate, a compound with high dielectric permittivity, was envisaged to increase the insulating properties of NR films, thereby reducing the electrical stress and the possibility of undesired arcing on their surfaces. The content of perovskite particles greatly affected both, the mechanical and the electrical properties, of the vulcanized films. It was observed that the optimum functionalized nanoparticle concentration is around 0.25–0.50 phr, range in which the elongation of break was maintained between 874–935% and the tensile strength was between 4.40–4.80 MPa; whereas the dielectric permittivity (¿') is slightly lower than the pristine NR or the NR compounded with high content of BaTiO3 nanoparticles. The dielectric study revealed the presence of two dielectric relaxation modes: (i) glass to rubber transition (a-relaxation) and (ii) interfacial polarization (IP), known as Maxwell-Wagner-Sillars (MWS) polarization. The comparison between small concentrations of non-functionalized and functionalized BaTiO3 inside NR polymeric films lead to the conclusion that the dielectric breakdown strength is high for non-functionalized fillers, supposedly due to less IP polarization phenomena.
Although carbon dioxide (CO2) is well known as one of the major green-house gases, it is also an economical C1 resource. Thus, CO2 has been regarded as an appealing starting material for the synthesis of polymers, like polycarbonates by the reaction with epoxides. Herein the reaction between natural epoxidized soybean oil (ESO), propylene oxide (PO) and CO2 under high pressure (4.0 MPa) with the presence of Co-Zn double metal cyanide (Co-Zn DMC) catalyst was studied. Temperature and reaction time were varied accordingly and the products obtained were characterized by FTIR, GPC and 1H NMR. The results obtained indicate the formation of polycarbonates in the samples collected with yields vary from 60 to 85%. The number average molecular weight (Mn) of the resultant polymer prepared at reaction temperature of 80 °C and reaction time of 6 h can reach up to 6498 g/mol.
This paper investigates the extension of a MultiParametric approach based on surrogate models (Meta-MultiParametric approach, M-MP) in order to handle general Mixed- Integer (MI) optimization problems involving Uncertain Parameters (UPs). The method harnesses metamodeling and clustering techniques in order to approximate black box relations between the optimal values of the continuous variables and the UPs, while Classification Techniques (CT) are employed to identify the optimal values of the integer variables also as a function of the UPs. The results of applying the method to a benchmark case-study show a high prediction accuracy of the optimal solutions, saving computational effort and overpassing the complex mathematical procedures required by the standard MultiParametric Programming methods.
A negotiation framework is proposed for the optimal design and operation of a decentralized supply chain. A formulation based on a competitive leader-follower environment, in which the leader should propose a set of negotiation contracts and, at the same time, predict the follower response (to accept/reject the contract) is proposed. The impact of the follower design decisions over the leader objective is evaluated by fixing the follower’s decision variables. Then by applying the Scenario Based Dynamic Negotiation method (considering the associated third parties price uncertainties) a set of feasible solutions is generated. Finally, using the Elimination and Choice Expressing Reality-IV method, the set of feasible solutions are evaluated under multiple defined criteria (including economic and environmental) in order to select a unique, optimal negotiation contract and its associated sustainable solution. This solution properly represents the leader’s and follower’s interests under a win-win negotiation partnership despite the uncontrollable/unpredicted behaviours resulted from the follower’s decisions as well as third party changing prices
In this contribution, the influence of Pulsed Electric Fields (PEF) of different intensities (3–9 kV/cm and 0–300 µs) on the extraction of Total Phenols from lemon peel residues by pressing was investigated. According to the cellular disintegration index, the optimum treatment time for the increase in permeability was determined as 30 pulses of 30 µs. It was determined that the effect of PEF was independent of lemon residue size. The effectiveness of pressing-assisted extraction was evaluated by measuring the Total Phenol Content (TPC), the real antioxidant capacity and the concentrations of the main lemon polyphenols, the flavonones hesperidin and eriocitrin. The variables studied in the extraction were time, pressure applied and intensity of the electric fields. This study concludes that electric field intensity of 7 kV/cm increased the efficiency of polyphenol extraction by 300%, giving maximum values of 84 mg of hesperidin in 100 g FW and 176 mg of eriocitrin in 100 g FW. Thus, it was concluded that PEF provides a new methodology to improve polyphenol extraction with a non-thermal, environment-friendly technology, and this represents a method for increasing economic benefits of industrial processes.
The conversion of infrared light to visible-light which allows a larger fraction of sun-light to be used is needed to improve light-harvesting. In this work a tri-functional material composed of an up-converter (NaYF4–Yb–Tm), plasmonic gold nanorods and CdS was made photocatalytically active using 980 nm wavelength light for the reduction of H+ to H2.
Natural rubber (NR) from Hevea brasiliensis is a material of great commercial interest because of its natural origin and low cost, being one of the most valuable elastomers obtained from renewable resources. In the electrical industry, insulating gloves made of NR are commonly used as protection against electric shock in low, medium and high voltage applications. Unfortunately, the physical and chemical behavior of these materials at a microscopic level and especially under conditions of high electrical stress is still quite unknown. Innovative and extensive studies on this are required to improve their performance. Another important aspect is the strong emergence of direct current (dc) applications in the low and medium voltage fields. This represents an added challenge to the application of these materials, since in some cases, the international standards impose even more restrictive test voltages than in the case of alternating current (ac). In this sense, this thesis proposes a strategy for latex compounding and particle size filler reduction, to investigate the physical-chemical properties of the final material, with special emphasis on the electrical properties. This thesis also aims at optimizing the behavior of the latex films under the application of ac and dc voltages, to maximize their dielectric breakdown voltage and reduce the leakage current, as also approached. Thus, in the first part of the thesis, the size reduction of filler particles, such as titanium dioxide (TiO2), zinc oxide (ZnO) and silicates is proposed by means of a sonication process. The objective was to reduce the leakage current in the NR polymer matrix because of tendency of the particles to form agglomerates. Usually, the ceramic additives, when agglomerated, act as charge dopants, increasing the electron conduction and dielectric loss. New formulations were also proposed, including non-functionalized and functionalized perovskite nanoparticles to manufacture insulating gloves with enhanced their properties at higher electric stress. Barium titanate (BaTiO3) was chosen as filler in nanosized dimensions (~100 nm), due to its high dielectric constant, low loss tangent (~10-2) and high breakdown strength. Non-fuctionalized BaTiO3 nanoparticles were added in different proportions to the NR formulation: 0.1 wt.%, 0.25 wt.%, 0.4 wt.% and 0.5 wt.%. In general, it was observed that by increasing the perovskite content in NR, the electric strength and capacitance of the samples were also increased. The electrical properties were evaluated using electrochemical impedance spectroscopy (EIS), volumetric and surface resistivity analysis and dielectric breakdown measurements under the application of ac voltages. In order to reduce the size of the agglomerates and improve the dispersion of the BaTiO3 nanoparticles in the NR matrix, it was proposed to functionalize BaTiO3 with hydrogen peroxide (H2O2). In this third stage, BaTiO3 nanoparticles previously functionalized with H2O2, were added to the NR polymer matrix in different concentrations: 0.25 wt.%, 0.5 wt.%, 1 wt. %, 5 wt.% and 10 wt.%; and in nanosized dimensions. Dielectric breakdown tests were performed under the application of dc voltages for both positive and negative polarity. The results obtained in the dc dielectric tests, showed that as the content of functionalized BaTiO3 increased in the NR matrix, the leakage current of the composite was reduced, compared to the NR pristine polymer.
Atout, H.; Alvarez , M.; Chebli, D.; Bouguettoucha, A.; Tichit, D.; Medina Cabello, Francisco; Llorca, J. Materials research bulletin Vol. 95, p. 578-587 DOI: 10.1016/j.materresbull.2017.08.029 Data de publicació: 2017-11 Article en revista
In this study, two different preparation methods of titanium dioxide nanoparticles/reduced graphene oxide nanocomposites were investigated using direct sol-gel method followed by hydrothermal treatment or simple hydrothermal route. A different amount of graphene (1- 20%) was mixed with TiO2 for both series of samples in order to improve the photocatalytic activity. The influence of the preparation method on the physico-chemical properties was established by different characterization methods and the photocatalytic degradation of methylene blue (MB) under UV light irradiation was used as test reaction. The highest photocatalytic activity was observed for the nanocomposites containing 10 wt% of graphene. The elimination of MB can reach 93% and 82% for the nanocomposites with 10 wt% graphene prepared by the sol-gel and hydrothermal methods, respectively. These photocatalysts are promising for practical application in nanotechnology.
This paper collects experimental data and mathematical modelling of Nd(III), Tb(III) and Dy(III) solvent extraction with an ionic liquid prepared from Aliquat 336 (Methyl-tri(octyl/decyl)ammonium chloride) and Oleic Acid (AliOle). Extraction experiments were carried out to evaluate the effect of chloride anion in aqueous phase, AliOle and REE concentrations over the extraction extension. Mathematical models computed with Matlab software were derived from the mass balances and chemical equilibria involved in the extraction system of Neodymium(III), Terbium(III) and Dysprosium(III) individually. The optimized equilibria parameters proposed fit accurately the experimental data and allowed us to predict the extraction extension of each metal from an aqueous mixture.
In this study, MCM-48 mesoporous silica was functionalized with dendrimer amines based on [1,3,5]-triazines (DA-S-Triazines), characterized by FT-IR, XRD, TEM and N2 sorption-desorption isotherm. The results confirmed the successful graft of organic functional groups on the MCM-48 surface. Then, it was used for the selective sorption of Ag (I) from aqueous solution and real wastewater in the batch system. The effect of main parameters on equilibrium sorption capacity and removal percentage including sorbent dose, pH, contact time, initial metal ion concentration and temperature was investigated. The results showed that the sorption of Ag (I) by DA-S-Triazines@MCM-48 was pH independent in the range of 3–8. The sorption capacity of MCM-48 strongly increases from 7.23 to 123 and 169.49 mg/g for HDA-S-Triazines@MCM-48 and DA-S-Triazines@MCM-48, respectively. The equilibrium data were fitted to nonlinear Freundlich, Temkin and Langmuir models, while a better fit was obtained by Freundlich model. According to the kinetic parameters, the sorption process was rapid. To selective sorption of Ag (I) from aqueous solution and real wastewater, the pore size of MCM-48 was exactly adjusted by changing the amount of DA-S-Triazines ligand. The results illustrated that the selective sorption of Ag (I) increased by increasing the amount of DA-S-Triazines ligand grafted on MCM-48 mesoporous silica. The results of sorption-desorption proved the economic synthesis and practical application of DA-S-Triazines@MCM-48 for sorption of Ag (I) from wastewater. DA-S-Triazines@MCM-48 as a potential sorbent showed high sorption capacity for sorption of Ag (I) from electroplating industry wastewater.
Garcia, Y.; Chirinos, J.; Bengoa, C.; Stüber, F.; Font, J.; Fortuny, A.; Fabregat, A. Chemical engineering and processing: Process Intensification Vol. 121, p. 57-64 DOI: 10.1016/j.cep.2017.08.001 Data de publicació: 2017-11-01 Article en revista
The anaerobic removal of nitrates was studied in a continuous up-flow stirred packed-bed reactor (USPBR) containing biological sludge carbonaceous material (BSCM). The carbonaceous material (CM), obtained from exhausted sludge, was used as support to grow the biofilm and solid electron mediator for nitrate reduction in the bioreactor. In a continuous USPBR-BSCM system feed with treated synthetic wastewaters, nitrate removal efficiency was 99% at very short space times (t) 2 min/hydraulic residence times (HRT) 6 min. By comparing these results with the hydraulic residence times applied in other classical denitrification technologies, it seems that USPBR-BSCM requires the shortest times to achieve almost complete nitrate removal. In addition, a high denitrification rate of 3.67 · 10-3 mmolNO3- min-1 g-1 was observed in the USPBR-BSCM, whilst in the USPBR-biological activated carbon (BAC) it was 2.04 · 10-3 mmolNO3- min-1 g-1. The kinetic analysis of the systems showed a good fit with the Michaelis–Menten model and the kinetic parameters estimated were k1 = 3.37 mmol L-1 min-1, k2 = 0.58 mmol L-1 for USPBR-BSCM and k1 = 2.50 mmol L-1 min-1, k2 = 0.27 mmol L-1 for USPBR-BAC. Results indicate that SCM is a potentially low cost catalyst and effectively competes with commercial ones; USPBR-BSCM is an inexpensive and advantageous process for nitrate removal and also an effective system for denitrification.
In general, peptides do not exhibit a well-defined conformational profile in solution. However, despite the experimental blurred picture associated with their structure, compelling spectroscopic evidence shows that peptides exhibit local order. The conformational profile of a peptide is the result of a balance between intramolecular interactions between different atoms of the molecule and intermolecular interactions between atoms of the molecule and the solvent. Accordingly, the conformational profile of a peptide will change upon the properties of the solvent it is soaked. To get insight into the balance between intra- and intermolecular interactions on the conformational preferences of the peptide backbone we have studied the conformational profile of the alanine dipeptide in diverse solvents using molecular dynamics as sampling technique. Solvents studied include chloroform, methanol, dimethyl sulfoxide, water and N-methylacetamide. Different treatments of the solvent have been studied in the present work including explicit solvent molecules, a generalized Born model and using the bulk dielectric constant of the solvent. The diverse calculations identify four major conformations with different populations in the diverse solvents: the C7 eq only sampled in chloroform; the C5 or extended conformation; the polyproline (PII) conformation and the right-handed a-helix conformation (aR). The results of present calculations permit to analyze how the balance between intra- and intermolecular interactions explains the populations of the diverse conformations observed.
Dombayci, C.; Espuña, A. International Joint Conference on Knowledge Discovery, Knowledge Engineering and Knowledge Management p. 147-154 DOI: 10.5220/0006485201470154 Data de presentació: 2017-11 Presentació treball a congrés
This paper presents the use of a Conceptual Constraint (CC) Domain to systematize the construction of Decision
Making Models (DMMs). The modelling systematics include the integration between the CC Domain
and production systems as well as an identification procedure which contains some steps aimed at constraint
identification using the CC Domain. The CC Domain consists of different modelling elements such as Conceptual
Constraints (generic constraint types), Conceptual Components (pieces of a constraint), and Conceptual
Component Elements (pieces of a conceptual component that may be connected to production systems). In
this instance, the CC Domain is integrated with the Process Systems Engineering (PSE) Domain as a production
system domain. The PSE Domain contains information from the multi-level functional hierarchical in an
enterprise and it will be used to cover a wide range of scenarios related to hierarchical integration of DMMs.
In addition, an integration step between the CC and PSE Domains is illustrated. The focus of the work is
to show how these models should be developed in order to be properly integrated, and how they are used by
different functionalities with an identification procedure.