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Search Results: 1 - 10 of 212991 matches for " Toni Pérez "
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Competition in the presence of aging: order, disorder, and synchronized collective behavior
Toni Pérez,Konstantin Klemm,Víctor M. Eguíluz
Physics , 2015,
Abstract: We study the stochastic dynamics of coupled states with transition probabilities depending on local persistence, this is, the time since a state has changed. When the population has a preference to adopt older states the system orders quickly due to the dominance of the old state. When preference for new states prevails, the system can show coexistence of states or synchronized collective behavior resulting in long ordering times. In this case, the magnetization $m(t)$ of the system oscillates around $m(t)=0$. Implications for social systems are discussed.
Structural and functional networks in complex systems with delay
Víctor M. Eguíluz,Toni Pérez,Javier Borge-Holtoefer,Alex Arenas
Computer Science , 2011, DOI: 10.1103/PhysRevE.83.056113
Abstract: Functional networks of complex systems are obtained from the analysis of the temporal activity of their components, and are often used to infer their unknown underlying connectivity. We obtain the equations relating topology and function in a system of diffusively delay-coupled elements in complex networks. We solve exactly the resulting equations in motifs (directed structures of three nodes), and in directed networks. The mean-field solution for directed uncorrelated networks shows that the clusterization of the activity is dominated by the in-degree of the nodes, and that the locking frequency decreases with increasing average degree. We find that the exponent of a power law degree distribution of the structural topology, b, is related to the exponent of the associated functional network as a =1/(2-b), for b < 2.
Persistence in voting behavior: stronghold dynamics in elections
Toni Pérez,Juan Fernández-Gracia,Jose J. Ramasco,Víctor M. Eguíluz
Computer Science , 2015, DOI: 10.1007/978-3-319-16268-3_18
Abstract: Influence among individuals is at the core of collective social phenomena such as the dissemination of ideas, beliefs or behaviors, social learning and the diffusion of innovations. Different mechanisms have been proposed to implement inter-agent influence in social models from the voter model, to majority rules, to the Granoveter model. Here we advance in this direction by confronting the recently introduced Social Influence and Recurrent Mobility (SIRM) model, that reproduces generic features of vote-shares at different geographical levels, with data in the US presidential elections. Our approach incorporates spatial and population diversity as inputs for the opinion dynamics while individuals' mobility provides a proxy for social context, and peer imitation accounts for social influence. The model captures the observed stationary background fluctuations in the vote-shares across counties. We study the so-called political strongholds, i.e., locations where the votes-shares for a party are systematically higher than average. A quantitative definition of a stronghold by means of persistence in time of fluctuations in the voting spatial distribution is introduced, and results from the US Presidential Elections during the period 1980-2012 are analyzed within this framework. We compare electoral results with simulations obtained with the SIRM model finding a good agreement both in terms of the number and the location of strongholds. The strongholds duration is also systematically characterized in the SIRM model. The results compare well with the electoral results data revealing an exponential decay in the persistence of the strongholds with time.
Effect of the Topology and Delayed Interactions in Neuronal Networks Synchronization
Toni Pérez, Guadalupe C. Garcia, Víctor M. Eguíluz, Raúl Vicente, Gordon Pipa, Claudio Mirasso
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0019900
Abstract: As important as the intrinsic properties of an individual nervous cell stands the network of neurons in which it is embedded and by virtue of which it acquires great part of its responsiveness and functionality. In this study we have explored how the topological properties and conduction delays of several classes of neural networks affect the capacity of their constituent cells to establish well-defined temporal relations among firing of their action potentials. This ability of a population of neurons to produce and maintain a millisecond-precise coordinated firing (either evoked by external stimuli or internally generated) is central to neural codes exploiting precise spike timing for the representation and communication of information. Our results, based on extensive simulations of conductance-based type of neurons in an oscillatory regime, indicate that only certain topologies of networks allow for a coordinated firing at a local and long-range scale simultaneously. Besides network architecture, axonal conduction delays are also observed to be another important factor in the generation of coherent spiking. We report that such communication latencies not only set the phase difference between the oscillatory activity of remote neural populations but determine whether the interconnected cells can set in any coherent firing at all. In this context, we have also investigated how the balance between the network synchronizing effects and the dispersive drift caused by inhomogeneities in natural firing frequencies across neurons is resolved. Finally, we show that the observed roles of conduction delays and frequency dispersion are not particular to canonical networks but experimentally measured anatomical networks such as the macaque cortical network can display the same type of behavior.
Synthesis of Gemcitabine-(C4-amide)-[anti-HER2/neu] Utilizing a UV-Photoactivated Gemcitabine Intermediate: Cytotoxic Anti-Neoplastic Activity against Chemotherapeutic-Resistant Mammary Adenocarcinoma SKBr-3  [PDF]
Cody P. Coyne, Toni Jones, Ryan Bear
Journal of Cancer Therapy (JCT) , 2012, DOI: 10.4236/jct.2012.325089
Abstract: Gemcitabine is a pyrimidine nucleoside analog that becomes triphosphorylated intracellularly where it competitively inhibits cytidine incorporation into DNA strands. Another mechanism-of-action of gemcitabine (diphosphorylated form) involves irreversible inhibition of the enzyme ribonucleotide reductase thereby preventing deoxyribonucleotide synthesis. Functioning as a potent chemotherapeutic gemcitabine promote decreases in neoplastic cell proliferation and apoptosis which is frequently found to be effective for the treatment of several leukemias and a wide spectrum of carcinomas. A brief plasma half-life in part due to rapid deamination and chemotherapeutic-resistance restricts the utility of gemcitabine in clinical oncology. Selective “targeted” delivery of gemcitabine represents a potential molecular strategy for simultaneously prolonging its plasma half-life and minimizing innocient tissues and organ systems exposure to chemotherapy. The molecular design and an organic chemistry based synthesis reaction is described that initially generates a UV-photoactivated gemcitabine intermediate. In a subsequent phase of the synthesis method the UV-photoactivated gemcitabine intermediate is covalently bonded to a monoclonal immunoglobulin yielding an end-product in the form of gemcitabine-(C4-amide)-[anti-HER2/neu]. Analysis by SDS-PAGE/chemiluminescent auto-radiography did not detect evidence of gemcitabine-(C4-amide)-[anti-HER2/neu] polymerization or degradative fragmentation while cell-ELISA demonstrated retained binding-avidity for HER2/neu trophic membrane receptor complexes highly over-expressed by chemotherapeutic-resistant mammary adenocarcinoma (SKBr-3). Compared to chemotherapeutic-resistant mammary adenocarcinoma (SKBr-3), the covalent immunochemotherapeutic, gemcitabine-(C4-amide)-[anti-HER2/neu] is anticipated to exert greater levels of cytotoxic anti-neoplastic potency against other neoplastic cell types like pancreatic carcinoma, small-cell lung carcinoma, neuroblastoma, glioblastoma, oral squamous cell carcinoma, cervical epitheliod carcinoma, or leukemia/lymphoid neoplastic cell types based on their reported sensitivity to gemcitabine and gemcitabine covalent conjugates.
Simultaneous Dual Selective Targeted Delivery of Two Covalent Gemcitabine Immunochemotherapeutics and Complementary Anti-Neoplastic Potency of [Se]-Methylselenocysteine  [PDF]
C. P. Coyne, Toni Jones, Ryan Bear
Journal of Cancer Therapy (JCT) , 2015, DOI: 10.4236/jct.2015.61009

The anti-metabolite chemotherapeutic, gemcitabine is relatively effective for a spectrum of neoplastic conditions that include various forms of leukemia and adenocarcinoma/carcinoma. Rapid systemic deamination of gemcitabine accounts for a brief plasma half-life but its sustained administration is often curtailed by sequelae and chemotherapeutic-resistance. A molecular strategy that diminishes these limitations is the molecular design and synthetic production of covalent gemcitabine immunoche-motherapeutics that possess properties of selective “targeted” delivery. The simultaneous dual selective “targeted” delivery of gemcitabine at two separate sites on the external surface membrane of a single cancer cell types represents a therapeutic approach that can increase cytosol chemotherapeutic deposition; prolong chemotherapeutic plasma half-life (reduces administration frequency); minimize innocent exposure of normal tissues and healthy organ systems; and ultimately enhance more rapid and thorough resolution of neoplastic cell populations. Materials and Methods: A light-reactive gemcitabine intermediate synthesized utilizing succinimidyl 4,4-azipentanoate was covalently bound to anti-EGFR or anti-HER2/neu IgG by exposure to UV light (354-nm) resulting in the synthesis of covalent immunoche-motherapeutics, gemcitabine-(C4-amide)-[anti-EGFR] and gemcitabine-(C4-amide)-[anti-HER2/neu]. Cytotoxic anti-neoplastic potency of gemcitabine-(C4-amide)-[anti-EGFR] and gemcitabine-(C4-amide)-[anti-HER2/neu] between gemcitabine-equivalent concentrations of 10-12 M and 10-6 M was determined utilizing chemotherapeutic-resistant mammary adenocarcinoma (SKRr-3). The organoselenium compound, [Se]-methylselenocysteine was evaluated to determine if it complemented the anti-neoplastic potency of the covalent gemcitabine immunoche-motherapeutics. Results: Gemcitabine-(C4-

The Adverse Event Profile in Patients Treated with TransferonTM (Dialyzable Leukocyte Extracts): A Preliminary Report  [PDF]
Toni Homberg, Violeta Sáenz, Jorge Galicia-Carreón, Iván Lara, Edgar Cervantes-Trujano, Maria C. Andaluz, Erika Vera, Oscar Pineda, Julio Ayala-Balboa, Alejandro Estrada-García, Sergio Estrada-Parra, Mayra Pérez-Tapia, Maria C. Jiménez-Martínez
Pharmacology & Pharmacy (PP) , 2015, DOI: 10.4236/pp.2015.62009
Abstract: Background: Dialyzable leukocyte extracts (DLE) are heterogeneous mixtures of peptides less than 10 kDa in size that are used as immunomodulatory adjuvants in immune-mediated diseases. TransferonTM is DLE manufactured by National Polytechnic Institute (IPN), and is registered by Mexican health-regulatory authorities as an immunomodulatory drug and commercialized nationally. The proposed mechanism of action of TransferonTM is induction of a Th1 immunoregulatory response. Despite that it is widely used, to date there are no reports of adverse events related to the clinical safety of human DLE or TransferonTM. Objective: To assess the safety of TransferonTM in a large group of patients exposed to DLE as adjuvant treatment. Methods: We included in this study 3844 patients from our Clinical Immunology Service at the Unit of External Services and Clinical Research (USEIC), IPN. Analysis was performed from January 2014 to November 2014, searching for clinical adverse events in patients with immune-mediated diseases and treated with TransferonTM as an adjuvant. Results: In this work we observed clinical nonserious adverse events (AE) in 1.9% of patients treated with TransferonTM (MD 1.9, IQR 1.7 - 2.0). AE were 2.8 times more frequently observed in female than in male patients. The most common AE were headache in 15.7%, followed by rash in 11.4%, increased disease-related symptomatology in 10%, rhinorrhea in 7.1%, cough in 5.7%, and fatigue in 5.7% of patients with AE. 63% of adverse event presentation occurred from day 1 to day 4 of treatment with Transferon
Citizenship, Space and Democracy: Political Changes in the Context of Globalization  [PDF]
Gabriel Pérez Pérez
Open Journal of Political Science (OJPS) , 2017, DOI: 10.4236/ojps.2017.71003
Abstract: The article makes a theoretical reflection of space, which has been traditionally studied by geographers and citizenship, without making aside the empirical elements of this relationship. The first paragraph provides that studying the citizenship is necessarily linking it to the issue of democracy, and that, if there have been different approaches for spatial analysis at different scales, we have a diversity of forms and developments that have embraced democracy and citizenship. The second section is central to the theme of the city and it shows how they are given different manifestations and expressions of citizenship that responds to the transformation of public space and the fragmentation of the city. Finally, the third section deals with the theme on how their times currently can observe the emergence of new or different formations citizens. As a consequence of the global transformations, migratory transnational flows or social movements, citizens can be studied through different scales and spaces.
Transformation of the Political Theory: Cosmopolitan Citizenship and Democracy  [PDF]
Gabriel Pérez Pérez
Open Journal of Political Science (OJPS) , 2019, DOI: 10.4236/ojps.2019.92018
Abstract: This paper is concerned with the topic of cosmopolitan citizenship and its relation to democracy. We begin by highlighting the main postulates of Kantian cosmopolitanism, as many theorists Kant contributes an idea of cosmopolitan citizenship linked to the need to establish international political institutions that support citizenship beyond an exclusively moral dimension. We then discuss the issue of the transformation undergone by the nation state in the context of globalization, particularly the loss of sovereignty of the state and the growth of multinational companies, and how these changes have come to set a new scenario for the emergence of international actors and the basis for various citizenship practices in a cosmopolitan dimension. The nature and current reach of cosmopolitan citizenship is explored through two fundamental cases: the European Union, and ecologic citizenship. Finally, we discuss cosmopolitan democracy and which ought to be its characteristics, among which we identify the establishment of supranational political institutions, the consolidation of a global civil society, and the establishment of mechanisms for citizen participation beyond the traditional ones situated in the national sphere.
Evaluation of genotoxicity using the micronucleus assay and nuclear abnormalities in the tropical sea fish Bathygobius soporator (Valenciennes, 1837) (Teleostei, Gobiidae)
Galindo, Toni P.;Moreira, Lília M.;
Genetics and Molecular Biology , 2009, DOI: 10.1590/S1415-47572009000200029
Abstract: the micronucleus and nuclear abnormalities assays have been used increasingly to evaluate genotoxicity of many compounds in polluted aquatic ecossystems. the aim of this study is to verify the efficiency of the micronucleus assay and nuclear abnormality assay in field and laboratory work, when using erythrocytes of the tropical marine fish bathygobius soporator as genotoxicity biomarkers. gill peripheral blood samples were obtained from specimens of bathygobius soporator. in order to investigate the frequencies of micronuclei and to assess the sensitivity of species, the results were compared with samples taken at the reference site and maintained in the laboratory, and fish treated with cyclophosphamide. the micronucleus assay was efficient in demonstrating field pollution and reproducing results in the labotatory. there were significant higher frequencies of micronuclei in two sites subject to discharge of urban and industrial effluents. the nuclear abnormality assay did not appear to be an efficient tool for genotoxicity evaluation when compared with field samples taken at a reference site in laboratory, with a positive control.
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