Limits on P Systems with Proteins and Without Division

In the field of Membrane Computing, computational complexity theory has been widely studied trying to nd frontiers of efficiency by means of syntactic or semantical ingredients. The objective of this is to nd two kinds of systems, one non-efficient and another one, at least, presumably efficient, that is, that can solve NP-complete prob- lems in polynomial time, and adapt a solution of such a problem in the former. If it is possible, then P = NP. Several borderlines have been defi ned, and new characterizations of different types of membrane systems have been published. In this work, a certain type of P system, where proteins act as a supporting element for a rule to be red, is studied. In particular, while division rules, the abstraction of cellular mitosis is forbidden, only problems from class P can be solved, in contrast to the result obtained allowing them.Ministerio de Economía y Competitividad TIN2017-89842-PNational Natural Science Foundation of China No 6132010600

Logarithmic SAT Solution with Membrane Computing

P systems have been known to provide efficient polynomial (often linear) deterministic solutions to hard problems. In particular, cP systems have been shown to provide very crisp and efficient solutions to such problems, which are typically linear with small coefficients. Building on a recent result by Henderson et al., which solves SAT in square-root-sublinear time, this paper proposes an orders-of-magnitude-faster solution, running in logarithmic time, and using a small fixed-sized alphabet and ruleset (25 rules). To the best of our knowledge, this is the fastest deterministic solution across all extant P system variants. Like all other cP solutions, it is a complete solution that is not a member of a uniform family (and thus does not require any preprocessing). Consequently, according to another reduction result by Henderson et al., cP systems can also solve k-colouring and several other NP-complete problems in logarithmic time

A new perspective on computational complexity theory in Membrane Computing

A single Turing machine can solve decision problems with an in nite number of instances. On the other hand, in the framework of membrane computing, a \solution" to an abstract decision problem consists of a family of membrane systems (where each system of the family is associated with a nite set of instances of the problem to be solved). An interesting question is to analyze the possibility to nd a single membrane system able to deal with the in nitely many instances of a decision problem. In this context, it is fundamental to de ne precisely how the instances of the problem are introduced into the system. In this paper, two different methods are considered: pre-computed (in polynomial time) resources and non-treated resources. An extended version of this work will be presented in the 20th International Conference on Membrane Computing.Ministerio de Economía, Industria y Competitividad TIN2017-89842-

Minimal cooperation in polarizationless P systems with active membranes

P systems with active membranes is a well developed framework in the eld of Membrane Computing. Using evolution, communication, dissolution and division rules, we know that some kinds of problems can be solved by those systems, but taking into account which ingredients are used. All these rules are inspired by the behavior of living cells, who \compute" with their proteins in order to obtain energy, create components, send information to other cells, kill themselves (in a process called apoptosis), and so on. But there are other behaviors not captured in this framework. As mitosis is simulated by division rules (for elementary and non-elementary membranes), meiosis, that is, membrane ssion inspiration is captured in separation rules. It di ers from the rst in the sense of duplication of the objects (that is, in division rules, we duplicate the objects not involved in the rule, meanwhile in separation rules we divide the content of the original membrane into the new membranes created). Evolution rules simulate the transformation of components in membranes, but it is well known that elements interact with another ones in order to obtain new components. Cooperation in evolution rules is considered. More speci cally, minimal cooperation (in the sense that only two objects can interact in order to create one or two objects

Solving Problems Through a Single Membrane System

The tape of a deterministic Turing machine contains an unbounded number of cells. Thanks to that, a single machine can solve decision problems with an infinite number of instances. Nevertheless, in the framework of membrane computing, traditionally a \solution" to an abstract decision problem consists of a family of membrane systems (where each system of the family is associated with a finite set of instances of the problem to be solved). An interesting question is to analyze the possibility to find a single membrane system able to deal with the infinitely many instances of a decision problem. In this context, it is fundamental to define precisely how the instances of the problem are introduced into the system. In this paper, two different methods are considered. The first one relies on a pre-computing process, where a polynomial-time computable function will be in charge of producing a multiset of objects associated with the instance to be solved. On the other hand, the second one assumes that the input alphabet of the system is equal to the alphabet of instances, and therefore instances are directly introduced in the initial configuration of the system. Polynomial complexity classes associated with these two approaches are introduced and some complexity aspects are studied.Ministerio de Economía, Industria y Competitividad TIN2017-89842-

Factors influencing the bioremoval of copper and zinc from wastewater using microalgae, bacteria, and their consortia

Water pollution by toxic heavy metals is a severe socio-sanitary problem that requires efficient, environmentally friendly, and economically viable solutions. Typical pig diets have a high content of phytates, which reduces the availability of Zn and Cu. Thus, to ensure animal health, welfare and productivity, pig diets are supplemented with these elements that are partially released to the ambient through the urine and feces. These residues represent an alarming problem nowadays, due to their high concentrations of carbon, nitrogen, phosphorous, and, of course, heavy metals and pharmaceutical products. Therefore, it is essential to develop an effective treatment of slurry generated in livestock facilities, which not only prevents contamination but also allows the recovery of organic matter and nutrients present in them, applying the concept of circular bioeconomy. This work aims to provide a sustainable solution to this issue, using microorganisms to treat and valorize wastewater from the food industry, in general, and livestock, in particular. The study focuses on the elimination of two metals (Cu and Zn) that, although essential at low concentrations, can be toxic when prolonged exposure to concentrations higher than required takes place. A bibliographic review has been carried out to evaluate the retention capacity of these elements by microalgae, bacteria, and their consortia, the experimental conditions in which metal retention takes place, and the predominant bioaccumulation mechanisms in each type of biomass. In the experimental part, a complete factorial design of 144 experiments has been applied to evaluate the effect of six factors on the bioelimination capacity of copper and zinc and the growth of the biomass. Three types of biomass were used: a pure Scenedesmus Almeriensis strain, a bacterial sludge, and a consortium of Scenedesmus Almeriensis and bacteria grown in slurry water. Furthermore, we selected other factors intending to study whether they influenced the retention process or not, such as organic matter, the CO2, the initial concentration of metals, the light, and the contact time. After the statistical analysis of the results, it was determined that the most important factors are the type of biomass (the pure microalgae showed the highest metal retention capacities), the initial metal concentration (the higher the concentration, the higher the retention), and stirring time (short times resulted in higher retention). For pure microalgae and slurry-grown biomass, significant biomass growth was observed. The results obtained from the retention capacities are promising since very high values were reached for copper and zinc metals, which makes it possible to consider the treatment of wastewater with high organic load and metals in photobioreactors as a promising method for the elimination heavy metal.La contaminación de las aguas por metales pesados tóxicos es un grave problema sociosanitario que requiere soluciones eficientes, respetuosas con el medio ambiente y económicamente viables. Típicamente, las dietas porcinas tienen un alto contenido en fitatos, que reducen la disponibilidad de Zn y Cu. Con el fin de asegurar su correcto desarrollo, los piensos que se dan a los cerdos se suplementan con estos dos elementos. La mayor parte de esos metales se expulsa con las heces, que suponen actualmente un problema medioambiental muy importante debido a sus elevadas concentraciones de carbono, nitrógeno y fósforo y, por supuesto de metales pesados y productos farmacéuticos. Resulta imprescindible, en la actualidad, un tratamiento efectivo de los purines generados en las instalaciones ganaderas, que no sólo evite la contaminación, sino que permita la recuperación de la materia orgánica y nutrientes presentes en los mismos, aplicando el concepto de bioeconomía circular. Este trabajo pretende dar una solución sostenible a este problema, usando microorganismos para tratar y valorizar aguas residuales de la industria alimentaria, en general, y ganadera, en particular. El estudio se centra en la eliminación de dos metales (Cu y Zn) que, aunque esenciales a bajas concentraciones, pueden resultar tóxicos cuando tiene lugar una exposición prolongada a concentraciones superiores a la requerida. Se ha llevado a cabo una revisión bibliográfica para evaluar la capacidad de retención de estos elementos por microalgas, bacterias y sus consorcios, las condiciones experimentales en las que la retención de metales tiene lugar y los mecanismos de bioacumulación predominantes en cada tipo de biomasa. En este trabajo se ha aplicado un diseño factorial completo de 144 experimentos para evaluar el efecto de seis factores sobre la capacidad de bioeliminación de cobre y cinc y sobre el crecimiento de la biomasa. Se hizo uso de tres tipos de biomasa: una cepa Scenedesmus Almeriensis pura, un fango de bacterias, y un consorcio de Scenedesmus Almeriensis y bacterias crecido en aguas de purín. Además, seleccionamos otros factores con la intención de estudiar si influían en el proceso de retención, como la materia orgánica, el CO2, la concentración inicial de metales, la luz, y el tiempo de contacto con la disolución. Tras el análisis estadístico de los resultados, se determinó que los factores más importantes son el tipo de biomasa (la microalga pura mostró las capacidades de retención de metales más altas), la concentración inicial de metal (a mayor concentración, mayores retenciones), y el tiempo de agitación (tiempos cortos resultaron en mayores retenciones). Para la microalga pura y biomasa crecida en purín, se observó un crecimiento de biomasa significativo. Los resultados que se obtuvieron de las capacidades de retención son prometedores, pues se alcanzaron valores muy altos para los metales cobre y cinc, que hacen que podamos considerar el tratamiento de aguas residuales con elevada carga orgánica y metales en fotobioreactores un método prometedor para la eliminación de metales pesados.Departamento de Química AnalíticaMáster en Técnicas Avanzadas en Química. Análisis y Control de Calidad Químico

Polarizationless P Systems with Active Membranes: Computational Complexity Aspects

P systems with active membranes, in their classical definition, make use of noncooperative rules only. However, it is well known that in living cells, proteins interact among them yielding new products. Inspired by this biological phenomenon, the previous framework is reformulated in this paper, allowing cooperation in object evolution rules, while removing electrical charges associated with membranes. More precisely, minimal cooperation in object evolution rules is incorporated in polarizationless P systems with active membranes. In this paper, the term “minimal” means that the left-hand side of such rules consists of at most two symbols, and its length is greater than or equal to the corresponding right-hand side. The computational efficiency of this kind of P systems is studied by providing a uniform polynomial-time solution to SAT problem in such manner that only division rules for elementary membranes are used and dissolution rules are forbidden. Bearing in mind that only tractable problems can be efficiently solved by families of polarizationless P systems with active membranes and without dissolution rules, passing from non-cooperation to minimal cooperation in object evolution rules amounts passing from non-efficiency to efficiency in this framework. This frontier of efficiency provides, as any other borderline does, a possible way to address the P versus NP problem.National Natural Science Foundation of China No. 61033003National Natural Science Foundation of China No. 6132010600

Novel monolithic materials for miniaturized separation techniques

En esta tesis, se describe el uso de nuevos materiales porosos polimericos y su potencial aplicación en técnicas de separación miniaturizadas. La primera sección (capítulos 1-3), contiene una introducción general, donde el impacto de los materiales polímeros (capítulo 2)en cromatografía es discutido. En el capítulo 3, se presenta una introducción a la caracterización de algunos polímeros y aceites esenciales. Los capítulos 1-3 se escribieron siguiendo la normativa de la Universidad Valencia. La segunda parte de esta tesis está enfocada en la preparación, caracterización y aplicación de nuevos materiales monoíticos usados en cromatografía líquida capilar y electrocromatografía (CEC). En estos sistemas miniaturizados, bajos caudales son usados, lo que implica que es necesario un control preciso del tiempo muerto y del tiempo de retraso del gradiente. Con este objetivo, un procedimiento fue desarrollado e implementado en cromatografos líquidos capilares disponibles comercialmente (capítulo 4). Este método fue aplicado a la determinación de parabenes en fluidos biologicos. En este método, columnas monolíticas de metacrilato acopladas en un equipo de cromatografía capilar y espectrometría de masas fue usado (capítulo 5). Una gran variedad de monómeros es una de las ventajas de las columnas monoliticas. Para obtener monolitos con las características cromatográficas deseadas, la modificación de la superficie del monolito es una de las estrategías comunmente escogidas. En consecuencia, es importante conocer el número de sitios reactivos disponibles para la funcionalización. En el capítulo 6, un método simple empleando cromatografía de gases y un detector de ionización de llama capaz de dar esta información fue desarrollado. En los siguientes capítulos, diferentes materiales monolíticos se prepararon modificando la superficie quimicante, para conseguir fases estacionarias con altas areas superficiales y mejora de sus propiedades cromatográficas. Para este propósito, diferentes ligandos como epinefrina (capítulo 7), fosfatidilcolina (capítulo 8) politiol (capítulo 9), un derivado de la codeina (Capítulo 10) y nanopartículas de plata (Capítulo 11) se han hecho reaccionar con la superficie de los monolítos. En muchos casos, la mejora de los porcentajes de recubrimiento han previsto a estas columnas con los más altos valoresde porcentaje de funcionalización publicados hasta la fecha. Estos materiales se han aplicado satisfactoriamente a la separación de diferentes tipos de analitos (alquil bencenos, hidrocarburos aromáticos, compuestos quirales, proteinas, etc.). Además, en la segunda parte de la tesis, se describe la síntesis de materiales polímericos híbridos usando nanopartículas magnéticas (capítulo 12). Una mejora del área respecto a los monolitos sin nanopartículas fue evidente, dando excelentes separaciones de pesticidas organofosforados. Finalmente, en la tercera parte de la tesis, se describe la caracterización de distintas materias primas por técnicas electroforéticas y cromatográficas. Polímeros solubles como el polivinil alcohol (capítulo 13), y un polímero rígidos espumoso (Rohacell, capítulo 14) usado en aplicaciones espaciales fueron estudiados. Además, se desarrollo un método para caracterizar la fracción alcoholica presente en aceites esenciales (capítulo 15) lo cual es de mucha importnacia en la industria del cuidado personal.In this PhD Thesis novel porous polymer materials and their potential application in miniaturized separation techniques are mainly described. The first section (Chapters 1-3), contains a general introduction, where the impact of monolithic materials (Chapter 2) on chromatography is widely discussed. In Chapter 3, an introduction to the characterization of some polymers and essential oils is presented. Chapters 1-3 were written in compliance with the aforementioned regulation of the University of Valencia, thus constituting the required general introduction. The second part of this PhD Thesis focuses on the preparation, characterization of application of novel monolithic materials to be used in capillary/nano liquid chromatography (c/nano-LC) and in capillary electrochromatography (CEC) as separation media. In these miniaturized LC systems, low flow rates (μL min–1) are used, which implies accurate control of the dead time and delay volumes (which is particularly critical for gradient elution). With this aim, a practical procedure to implement synchronized gradient elution in commercial cLC systems was developed (Chapter 4). The benefits of synchronization on efficiency and time saving were demonstrated. Taking into account this synchronization approach, a method for the determination of parabens in biological fluids was developed. In this method, methacrylate monoliths and nano-LC coupled to mass spectrometry (MS) were used (Chapter 5). The wide variety of easily available chemistries is one of the advantages of polymeric monolithic columns. To obtain monoliths with the desired chromatographic properties, the chemical modification of reactive monoliths is one of the strategies most commonly adopted. Consequently, it is important to know both the number of reactive sites available for functionalization and the functionalization yield. In Chapter 6, a simple gas chromatography – flame ionization detector (GC-FID) method capable of providing this information is described. In the following chapters, different monolithic materials were prepared by chemical modification of its pore surface, in order to achieve stationary phases with enlarged areas and enhanced properties. For this purpose, several ligands as epinephrine (Chapter 7), phosphatidylcholine (Chapter 8), polythiol (Chapter 9), a codeine derivative (Chapter 10), and silver nanoparticles (Chapter 11), among others, have been attached onto the pore surface. In some cases, the enhancement of pore surface coverage with these ligands has provided the highest values published until now. These materials have been successfully applied in the separation of different types of target analytes (alkyl benzenes, aromatic hydrocarbonds, chiral compounds, proteins, etc.). Also, in this second part, the synthesis and applications of hybrid porous polymeric materials using magnetic nanoparticles (Chapter 12) have been described. An enhancement of the surface area of these monoliths with respect to the parent monolith, giving rise to excellent separations of organophosphorous pesticides, has been demonstrated. Finally, in the third part of this PhD Thesis, the characterization of different raw materials by electromigration and chromatographic techniques is described. Within these materials, water soluble polymers such as polyvinyl alcohol (Chapter 13) (used as additive in laundry products) and a rigid polymeric foam (Rohacell®, Chapter 14) which is used in aeronautical and space applications were studied. Also, a method for the analysis of the alcoholic constituents present in essential oils (Chapter 15), of importance in cosmetic and personal care products, was developed

Solution to Shortest Path Problem Using a Connective Probe Machine

With the continuous urban scale expansion, traffic networks have become extremely complex. Finding an optimal route in the shortest time has become a difficult and important issue in traffic engineering study. In this study, a novel computing model, namely, probe machine, is used to solve this problem. Similar to previous studies, urban transport networks can be abstracted into maps, in which points representing places of origin, destinations, and other buildings constitute the data library and edges representing the road make up the probe library. The true solution can be obtained after one probe operation on the computing platform. And by comparing the solving process with Dijkstra’s and Floyd’s algorithms, the computing efficiency of the probe machine is clearly superior, although all three methods can solve the shortest path problem and obtain the same solution. Document type: Articl

In Memoriam, Solomon Marcus

This book commemorates Solomon Marcus’s fifth death anniversary with a selection of articles in mathematics, theoretical computer science, and physics written by authors who work in Marcus’s research fields, some of whom have been influenced by his results and/or have collaborated with him