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Bioanode of Polyurethane/Graphite/Polypyrrole Composite in Microbial Fuel Cells
Pedro Perez-Rodriguez,Víctor M. Ovando-Medina,Silvia Y. Martinez-Amador,Jose A. Rodriguez-de la Garza 한국생물공학회 2016 Biotechnology and Bioprocess Engineering Vol.21 No.2
Polyurethane (PU) foams were coated with graphite, and pyrrole monomer was subsequently polymerized onto its surface by chemical oxidization to obtain nanostructured polyurethane/graphite/polypyrrole (PU/Graph/PPy) composites, which were used for anaerobic microorganisms grown and tested as anodes in microbial fuel cells (MFC) using municipal wastewater as fuel. The effects of oxidizing agent type (ammonium persulfate and FeCl3) used in pyrrole polymerization on the performance of electrodes in MFC were studied. Composites were characterized by Fourier Transform Infrared (FTIR) spectroscopy, Scanning Electron Microscopy (SEM), and by the four-point probes to determine conductivity. It was observed from SEM analysis that globular nanostructures of PPy were formed onto PU surface with average diameters between 120 and 450 nm, which are typical of aqueous polymerization of pyrrole monomer. The highest output power density observed in MFCs was 305.5 mW/m3 for the composite synthesized using FeCl3 as the oxidant, and 128.6 mW/m3 using the composite obtained with ammonium persulfate as oxidizing; the corresponding chemical oxygen demand (COD) removal were 48.2 and 45.5%, respectively. The calculated coulombic efficiency for PU/Graph/PPy composite obtained with FeCl3 as oxidant was of 9.4%. Internal resistance of MFC using the composite obtained with FeCl3 as oxidant was determined by linear sweep voltammetry (LSV) and the variable resistance (VR) methods, giving 4.8 and 2.9 kΩ, respectively, with average maximum power density of 237.5 mW/m3.
Evaluation of the Use of Guard Nodes for Securing the Routing in VANETs
Martinez, Juan A.,Vigueras, Daniel,Ros, Francisco J.,Ruiz, Pedro M. The Korea Institute of Information and Commucation 2013 Journal of communications and networks Vol.15 No.2
We address the problem of effective vehicular routing in hostile scenarios where malicious nodes intend to jeopardize the delivery of messages. Compromised vehicles can severely affect the performance of the network by a number of attacks, such as selectively dropping messages, manipulating them on the fly, and the likes. One of the best performing solutions that has been used in static wireless sensor networks to deal with these attacks is based on the concept of watchdog nodes (also known as guard nodes) that collaborate to continue the forwarding of data packets in case a malicious behavior in a neighbor node is detected. In this work, we consider the beacon-less routing algorithm for vehicular environments routing protocol, which has been previously shown to perform very well in vehicular networks, and analyze whether a similar solution would be feasible for vehicular environments. Our simulation results in an urban scenario show that watchdog nodes are able to avoid up to a 50% of packet drops across different network densities and for different number of attackers, without introducing a significant increase in terms of control overhead. However, the overall performance of the routing protocol is still far from optimal. Thus, in the case of vehicular networks, watchdog nodes alone are not able to completely alleviate these security threats.
MicroRNAs and periodontal disease: a qualitative systematic review of human studies
Mico-Martinez, Pablo,Alminana-Pastor, Pedro J.,Alpiste-Illueca, Francisco,Lopez-Roldan, Andres Korean Academy of Periodontology 2021 Journal of Periodontal & Implant Science Vol.51 No.-
Purpose: MicroRNAs (miRNAs) are epigenetic post-transcriptional regulators that modulate gene expression and have been identified as biomarkers for several diseases, including cancer. This study aimed to systematically review the relationship between miRNAs and periodontal disease in humans, and to evaluate the potential of miRNAs as diagnostic and prognostic biomarkers of disease. Methods: The review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines (reference number CRD42020180683). The MEDLINE, Scopus, Cochrane Library, Embase, Web of Science, and SciELO databases were searched for clinical studies conducted in humans investigating periodontal diseases and miRNAs. Expression levels of miRNAs across the different groups were analysed using the collected data. Results: A total of 1,299 references were identified in the initial literature search, and 23 articles were finally included in the review. The study designs were heterogeneous, which prevented a meta-analysis of the data. Most of the studies compared miRNA expression levels between patients with periodontitis and healthy controls. The most widely researched miRNA in periodontal diseases was miR-146a. Most studies reported higher expression levels of miR-146a in patients with periodontitis than in healthy controls. In addition, many studies also focused on identifying target genes of the differentially expressed miRNAs that were significantly related to periodontal inflammation. Conclusions: The results of the studies that we analysed are promising, but diagnostic tests are needed to confirm the use of miRNAs as biomarkers to monitor and aid in the early diagnosis of periodontitis in clinical practice.
LAGUERRE EXPANSIONS AND PRODUCTS OF DISTRIBUTIONS
Catuogno, Pedro,Martinez, Federico,Molina, Sandra Korean Mathematical Society 2008 대한수학회논문집 Vol.23 No.2
In this paper we introduce two products of tempered distributions with positive support. These products are based in the Laguerre representation of distributions. We calculate some products as, $[{\delta}]x^{\lambda}_+={\delta}[x^{\lambda}_+]=0\;and\;[x^{\lambda}_+]x^{\mu}_+=x^{{\lambda}+{\mu}}_+$ for appropriate ${\lambda}$ and ${\mu}$.
Ruben Lostado,Pedro Villanueva Roldán,Roberto Fernandez Martinez,Bryan J. Mac Donald 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.8
The purpose of this paper is to show the design and optimization of a novel electromagnetic servo brake incorporating an Antilock brake system (ABS) function by Multi-objective genetic algorithms. To consider different design requirements, three types of Axisymmetric Finite element (FE) models were initially formulated parametrically to determine the braking force and position of the pusher at each instant during operation of the proposed device. Using a combination of the FE models and Weight-based multi-objective genetic algorithms (WBMOGA), the optimal geometry and dimensions of the proposed FE models were determined while maximizing the braking force of the device and minimizing both the current supplied by the battery and the weight of the assembly. Once an optimal configuration for each type of servo brake designed had been achieved, three prototypes were built and validated experimentally on a conventional test bench. Finally, the prototype that performed best of the three prototypes was mounted and tested on a hybrid test bench with a realistic ABS device. The good agreement between the results obtained from the simulations and those measured experimentally, suggests that the combination of FE models and WBMOGA may be used successfully to design and optimize any complex electromechanical device.
Evaluation of the Use of Guard Nodes for Securing the Routing in VANETs
Juan A. Martinez,Daniel Vigueras,Francisco J. Ros,Pedro M. Ruiz 한국통신학회 2013 Journal of communications and networks Vol.15 No.2
We address the problem of effective vehicular routing in hostile scenarios where malicious nodes intend to jeopardize the delivery of messages. Compromised vehicles can severely affect the performance of the network by a number of attacks, such as selectively dropping messages, manipulating them on the fly, and the likes. One of the best performing solutions that has been used in static wireless sensor networks to deal with these attacks is based on the concept of watchdog nodes (also known as guard nodes) that collaborate to continue the forwarding of data packets in case a malicious behavior in a neighbor node is detected. In this work,we consider the beacon-less routing algorithm for vehicular environments routing protocol, which has been previously shown to perform very well in vehicular networks, and analyze whether a similar solution would be feasible for vehicular environments. Our simulation results in an urban scenario show that watchdog nodes are able to avoid up to a 50% of packet drops across different network densities and for different number of attackers, without introducing a significant increase in terms of control overhead. However, the overall performance of the routing protocol is still far from optimal. Thus, in the case of vehicular networks, watchdog nodes alone are not able to completely alleviate these security threats.
Yaw effects on train aerodynamics on a double-track viaduct: A wind tunnel study
Wenhui Li,Tanghong Liu,Pedro Martinez-Vazquez,Zhengwei Chen,Xiaoshuai Huo,Zijian Guo,Yutao Xia 한국풍공학회 2021 Wind and Structures, An International Journal (WAS Vol.33 No.3
The aerodynamic performance of a scaled high-speed train model mounted on a double-track viaduct was studied through a wind tunnel test. The pressure distribution of different loops and the centerline on the streamlined nose region, as well as the aerodynamic load coefficients of the leading car were explored under yaw effects ranging from β=-30° to β=30°. Results showed that Reynolds effects became independent when the wind speed surpassed 40 m/s, the corresponding Re of which equals 6.51 × 105 . The pressures recorded along the centerline of train nose for the upstream scenario, was more sensitive to the yaw effects as the largest pressure difference gradually broadened against yaw angles. In addition, the pressure coefficients along the centerline and symmetrical taps of the loops, approximately fit a quadratic relationship with respect to yaw angles. The presence of the tracks and viaduct decks somehow mitigated the intensity of the airflow at downstream side. The experimental test also revealed that, the upstream configuration provided higher mean side force, yawing, and rolling moments up to β=20° whereas over that angle the force and moments exhibited the opposite performance.
Ascospore Infection and Colletotrichum Species Causing Glomerella Leaf Spot of Apple in Uruguay
Alaniz, Sandra,Cuozzo, Vanessa,Martinez, Valentina,Stadnik, Marciel J.,Mondino, Pedro The Korean Society of Plant Pathology 2019 Plant Pathology Journal Vol.35 No.2
Glomerella leaf spot (GLS) caused by Colletotrichum spp. is a destructive disease of apple restricted to a few regions worldwide. The distribution and evolution of GLS symptoms were observed for two years in Uruguay. The recurrent ascopore production on leaves and the widespread randomized distribution of symptoms throughout trees and orchard, suggest that ascospores play an important role in the disease dispersion. The ability of ascospores to produce typical GLS symptom was demonstrated by artificial inoculation. Colletotrichum strains causing GLS did not result in rot development, despite remaining alive in fruit lesions. Based on phylogenetic analysis of actin, ${\beta}$-tubulin and glyceraldehyde-3-phosphate dehydrogenase gene regions of 46 isolates, 25 from fruits and 21 from leaves, C. karstii was identified for the first time causing GLS in Uruguay and C. fructicola was found to be the most frequent (89%) and aggressive species. The higher aggressiveness of C. fructicola and its ability on to produce abundant fertile perithecia could help to explain the predominance of this species in the field.