juan garcia - Academia.edu (original) (raw)

Papers by juan garcia

In this paper the effect of air presence in an emergency cooling system of a nuclear power plant ... more In this paper the effect of air presence in an emergency cooling system of a nuclear power plant during the pipelines pressurization stage is analyzed. The pressure waves propagation along the system pipelines after a fast pressurization of the water tanks is considered. The presence of different amounts of air in one pipe is analyzed. A code was developed to

IEEE International Symposium on Intelligent Signal Processing, 2011

This paper proposes a way to improve the position estimates in an indoor location systems (ILS) b... more This paper proposes a way to improve the position estimates in an indoor location systems (ILS) based on readings from the power levels (RSSI) of an ad hoc ZigBee network. A mobile object, also equipped with a ZigBee device, can be located, positioned, and tracked by the system. The initial estimate of the mobile node position is extracted from IC devices from Texas Instruments, equipped with a specific hardware module for this function called Location Engine; it computes its position from RSSI readings of the signals coming from a set of reference beacons. Positioning of the blind nodes is enhanced by a post-filtering of the initial estimates by adjusting them into a Metric Description Graph (MDG) of the building, which includes information on distances and connectivity among the various enclosures of the coverage area of the ILS. The system has been experimentally verified in localization tasks of pedestrians in indoor environments.

IEEE International Symposium on Intelligent Signal Processing, 2005

This work deals with the use of sets to code multi-mode seasonal system, similar to code-division... more This work deals with the use of sets to code multi-mode seasonal system, similar to code-division multiple-access (CDMA) communication ones. In multi-sensorial systems, as multi-user ones, it is necessary to avoid the multiple-access interference (MAI). We propose the use of mutually orthogonal complementary sets of sequences (MO-CSS) to avoid MAI among the sensors that are working simultaneously. This proposal sometimes

Chemical bath deposition techniques for bismuth sulfide, bismuth selenide, antimony sulfide, and ... more Chemical bath deposition techniques for bismuth sulfide, bismuth selenide, antimony sulfide, and antimony selenide thin films of about 0.20 - 0.25 micrometer thickness are reported. All these materials may be considered as solar absorber films: strong optical absorption edges, with absorption coefficient, (alpha) , greater than 104 cm-1, are located at 1.31 eV for Bi2Se3, 1.33 eV for Bi2S3, 1.8 eV for Sb2S3, and 1.35 eV for Sb2Se3. As deposited, all the films are nearly amorphous. However, well defined crystalline peaks matching bismuthinite (JCPDS 17- 0320), paraguanajuatite (JCPDS 33-0214), and stibnite (JCPDS 6-0474) and antimony selenide (JCPDS 15-0861) for Bi2S3, Bi2Se3, Sb2S3 and Sb2Se3 respectively, are observed when the films are annealed in nitrogen at 300 degrees Celsius. This is accompanied by a substantial modification of the electrical conductivity in the films: from 10-7 (Omega) -1 cm-1 (in as prepared films) to 10 (Omega) -1 cm-1 in the case of bismuth sulfide and selenide films, and enhancement of photosensitivity in the case of antimony sulfide films. The chemical deposition of a CuS/CuxSe film on these Vx- VIy films and subsequent annealing at 300 degrees Celsius for 1 h at 1 torr of nitrogen leads to the formation of p-type films (conductivity of 1 - 100 (Omega) -1 cm-1) of multinary composition. Among these, the formation of Cu3BiS3 (JCPDS 9-0488) and Cu3SbS4 (JCPDS 35- 0581), CuSbS2 (JCPDS 35-0413) have been clearly detected. Solar energy applications of these films are suggested.

Eppo Bulletin, 2006

Among the biotechnological uses of plant viruses, the expression of foreign sequences through vir... more Among the biotechnological uses of plant viruses, the expression of foreign sequences through virus-based vectors represents a promising research area. The potyvirus Plum pox virus (PPV) has been used to design expression vectors which have allowed successful expression of foreign sequences in plants, either in the form of small peptides fused to the viral coat protein, or as whole independent proteins inserted on different points of the genome. The present review describes the different PPV-based vectors that have been produced, including information regarding relevant aspects of their use, such as the optimal location of peptides or the stability of inserts. Recent developments, like the expression of proteins on stone fruit trees by using PPV-based vectors capable to infect woody plants, are also described.

Enfermedades Infecciosas Y Microbiologia Clinica, 2007

co mostró una epidermis conservada con un infiltrado inflamatorio exuberante en dermis con formac... more co mostró una epidermis conservada con un infiltrado inflamatorio exuberante en dermis con formación de abscesos de células polimorfonucleares rodeados de células histiocitarias epitelioides y una capa más externa de células mononucleares. No se observaron granulomas. Las tinciones de Gram y PAS fueron negativas y la de Ziehl-Neelsen, positiva. Los cultivos convencionales bacterianos y fúngicos y los bacterianos en incubación prolongada fueron negativos.

Journal of Hazardous Materials, 2009

Activated carbon was utilized as adsorbent to remove anionic dye, Orange II (OII), and cationic d... more Activated carbon was utilized as adsorbent to remove anionic dye, Orange II (OII), and cationic dye, Methylene blue (MB), from aqueous solutions by adsorption. Batch experiments were conducted to study the effects of temperature (30–65 °C), initial concentration of adsorbate (300–500 mg L−1) and pH (3.0–9.0) on dyes adsorption. Equilibrium adsorption isotherms and kinetics were investigated. The equilibrium experimental data were analyzed by the Langmuir, Freundlich, Toth and Redlich–Peterson models. The kinetic data obtained with different carbon mass were analyzed using a pseudo-first order, pseudo-second order, intraparticle diffusion, Bangham and Chien–Clayton equations. The best results were achieved with the Langmuir isotherm equilibrium model and with the pseudo-second order kinetic model. The activated carbon was found to be very effective as adsorbent for MB and OII from aqueous solutions.

Fertility and Sterility, 2010

It is assumed somatic cells can die in the apoptotic, the autophagic, or the necrotic way; howeve... more It is assumed somatic cells can die in the apoptotic, the autophagic, or the necrotic way; however, the mechanisms of sperm death are not clear. Here, ejaculated human spermatozoa were evaluated for apoptosis and reactive oxygen species production in the absence or presence of melatonin, and we concluded that melatonin reverses sperm apoptosis due to its free radical scavenging actions.

IEEE Instrumentation and Measurement Technology Conference, 2009

This paper presents a new algorithm to obtain the position of a mobile with an ultrasonic local p... more This paper presents a new algorithm to obtain the position of a mobile with an ultrasonic local positioning system (US-LPS). The system consists of five beacons placed in the ceiling covering a wide working area. The simultaneous emissions of all the beacons are synchronized, and encoded by using a DS-CDMA technique with five different 255-bit Kasami sequences. A receiver is placed on the mobile to be positioned and its position is calculated by hyperbolic trilateration using the differences in times of arrival (DTOA) between the received signals (considering one of them as reference) obtained by correlation. With the DTOAs, the position of the mobile device is computed by using a new Cayley-Menger bideterminant-based algorithm. Compared to traditional methods, as the minimization of non-linear equations by the Newton-Gauss algorithm, the new algorithm is easier to implement (no iterations are needed) and it achieves similar performances. Both, simulated and real results are presented for this new algorithm.

RESUMEN: Los trabajadores de la salud se encuentran en riesgo permanente de adquisición de enferm... more RESUMEN: Los trabajadores de la salud se encuentran en riesgo permanente de adquisición de enfermedades infecciosas. La transmisión de agentes infecciosos por sangre o fluidos corporales (virus de la inmunodeficiencia humana, virus de hepatitis B y virus de hepatitis C) puede ser evitada. El objetivo es evaluar la utilización de medidas de profilaxis pre-exposición de los accidentes laborales en trabajadores de la salud. Métodos: Se realizó un estudio clínico, transversal y descriptivo. Se incluyeron todos los casos de accidentes laborales reportados al Servicio de Enfermedades Infecciosas -Hospital de Niños "J.M. de Los Ríos". Período 2000-2001. Resultados: Se reportaron 42 accidentes en 42 trabajadores (personal médico 50 %, enfermería 29 %, limpieza 12 % y laboratorio 9 %). Sexo femenino 76 % y masculino 24 %. 98 % tenía edad entre 25-44 años. 50 % de los accidentes ocurrió durante la realización de procedimientos quirúrgicos, 29 % desechando inadecuadamente material y 21 % encapuchando agujas. 90 % de los accidentes fueron por punción. De los 21 accidentes por procedimientos quirúrgicos, 57 % ocurrieron durante el acceso venoso. 29 % de los trabajadores no usó protección de barrera durante los procedimientos quirúrgicos. De los trabajadores que usaban protección, 100 % tenía guantes, 80 % protección ocular y 53 % protección nasolabial. 51 % de los trabajadores había recibido esquema completo de inmunización para virus de hepatitis B, mientras que 22 % no tenía ninguna dosis de vacuna. Conclusiones: 50 % de los accidentes pudieron ser prevenidos (desechando adecuadamente material y evitando encapuchar agujas). 29 % de los trabajadores con accidentes durante procedimientos quirúrgicos, no utilizó medidas preventivas de barrera. Sólo 51 % de todos los trabajadores tenía inmunización para virus de hepatitis B.

Artificial vision provides a remarkable good sensor when developing applications for intelligent ... more Artificial vision provides a remarkable good sensor when developing applications for intelligent spaces. Cameras are passive sensors that supply a great amount of information and are quite cheap. This paper presents an application for elderly care that detects falls or faints and automatically triggers the health alarm. It promotes the independent lifestyle of elder people at their homes as the monitoring application will call for timely health assistance when needed. The system extracts 3D information from several cameras and performs 3D tracking of the people in the intelligent space. Two evolutive multimodal algorithms have been developed to continuously estimate the 3D position in real time, one based on 3D points and another one based on 3D prisms. Both learn the visual appearance of the persons and use color and movement as tracking cues. The system has been validated with some experiments in different real environments.

Fuel Processing Technology, 2009

The present work is devoted to determine the magnitude of the main parameters that yield the opti... more The present work is devoted to determine the magnitude of the main parameters that yield the optimum results for twin-fluid nozzles with an internal mixing chamber. The focus is placed on the study of the interaction of both air and liquid flows at the internal chamber and its effects on the resulting spray. To this end, some experiments have been performed for different air central channel diameters and liquid ports, as well as for several experimental conditions (air and liquid mass flow rates), in order to understand the influence of the flow conditions at the mixing chamber on the size of the droplets produced. It has been demonstrated that under certain experimental conditions the atomizing fluid discharged to the internal chamber is choked. The sonic condition is achieved for different air and liquid mass flow rates as a function of the air central channel diameter. It has also been obtained that to achieve the best results with moderate atomizing fluid flow rates, it is convenient to operate in choked conditions. This is an important result that will help in the optimum design of this type of nozzles.

PLoS pathogens, 2014

The replication of many RNA viruses involves the translation of polyproteins, whose processing by... more The replication of many RNA viruses involves the translation of polyproteins, whose processing by endopeptidases is a critical step for the release of functional subunits. P1 is the first protease encoded in plant potyvirus genomes; once activated by an as-yet-unknown host factor, it acts in cis on its own C-terminal end, hydrolyzing the P1-HCPro junction. Earlier research suggests that P1 cooperates with HCPro to inhibit host RNA silencing defenses. Using Plum pox virus as a model, we show that although P1 does not have a major direct role in RNA silencing suppression, it can indeed modulate HCPro function by its self-cleavage activity. To study P1 protease regulation, we used bioinformatic analysis and in vitro activity experiments to map the core C-terminal catalytic domain. We present evidence that the hypervariable region that precedes the protease domain is predicted as intrinsically disordered, and that it behaves as a negative regulator of P1 proteolytic activity in in vitro cleavage assays. In viral infections, removal of the P1 protease antagonistic regulator is associated with greater symptom severity, induction of salicylate-dependent pathogenesis-related proteins, and reduced viral loads. We suggest that fine modulation of a viral protease activity has evolved to keep viral amplification below hostdetrimental levels, and thus to maintain higher long-term replicative capacity.

Journal of virology, 2014

The helper component proteinase (HCPro) is an indispensable, multifunctional protein of members o... more The helper component proteinase (HCPro) is an indispensable, multifunctional protein of members of the genus Potyvirus and other viruses of the family Potyviridae. This viral factor is directly involved in diverse steps of viral infection, such as aphid transmission, polyprotein processing, and suppression of host antiviral RNA silencing. In this paper, we show that although a chimeric virus based on the potyvirus Plum pox virus lacking HCPro, which was replaced by a heterologous silencing suppressor, caused an efficient infection in Nicotiana benthamiana plants, its viral progeny had very reduced infectivity. Making use of different approaches, here, we provide direct evidence of a previously unknown function of HCPro in which the viral factor enhances the stability of its cognate capsid protein (CP), positively affecting the yield of virions and consequently improving the infectivity of the viral progeny. Site-directed mutagenesis revealed that the ability of HCPro to stabilize CP and enhance the yield of infectious viral particles is not linked to any of its previously known activities and helped us to delimit the region of HCPro involved in this function in the central region of the protein. Moreover, the function is highly specific and cannot be fulfilled by the HCPro of a heterologous potyvirus. The importance of this novel requirement in regulating the sorting of the viral genome to be subjected to replication, translation, and encapsidation, thus contributing to the synchronization of these viral processes, is discussed.

Plant methods, 2014

Background: Fluorescent proteins are extraordinary tools for biology studies due to their versati... more Background: Fluorescent proteins are extraordinary tools for biology studies due to their versatility; they are used extensively to improve comprehension of plant-microbe interactions. The viral infection process can easily be tracked and imaged in a plant with fluorescent protein-tagged viruses. In plants, fluorescent protein genes are among the most commonly used reporters in transient RNA silencing and heterologous protein expression assays. Fluorescence intensity is used to quantify fluorescent protein accumulation by image analysis or spectroscopy of protein extracts; however, these methods might not be suitable for medium-to large-scale comparisons. Results: We report that laser scanners, used routinely in proteomic studies, are suitable for quantitative imaging of plant leaves that express different fluorescent protein pairs. We developed a microtiter plate fluorescence spectroscopy method for direct quantitative comparison of fluorescent protein accumulation in intact leaf discs. We used this technique to measure a fluorescent reporter in a transient RNA silencing suppression assay, and also to monitor early amplification dynamics of a fluorescent protein-labeled potyvirus. Conclusions: Laser scanners allow dual-color fluorescence imaging of leaf samples, which might not be acquired in standard stereomicroscope devices. Fluorescence microtiter plate analysis of intact leaf discs can be used for rapid, accurate quantitative comparison of fluorescent protein accumulation.

International journal of systematic and evolutionary microbiology, 2015

A Gram-negative, spiral-shaped, chemolithotrophic, ammonia-oxidizing bacterium, designated APG3 T... more A Gram-negative, spiral-shaped, chemolithotrophic, ammonia-oxidizing bacterium, designated APG3 T , was isolated into pure culture from sandy lake sediment collected from Green Lake, Seattle, WA, USA. Phylogenetic analyses based on the 16S rRNA gene sequence showed that strain APG3 T belongs to cluster 0 of the genus Nitrosospira, which is presently not represented by described species, with Nitrosospira multiformis (cluster 3) as the closest species with a validly published name (identity of 98.6 % to the type strain). Strain APG3 T grew at 4 6C but could not grow at 35 6C, indicating that this bacterium is psychrotolerant. Remarkably, the strain was able to grow over a wide range of pH (pH 5-9), which was greater than the pH range of any studied ammonia-oxidizing bacteria in pure culture. The DNA G+C content of the APG3 T genome is 53.5 %, which is similar to that of Nitrosospira multiformis ATCC 25196 T (53.9 %) but higher than that of Nitrosomonas europaea ATCC 19718 (50.7 %) and Nitrosomonas eutropha C71 (48.5 %). The average nucleotide identity (ANI) calculated for the genomes of strain APG3 T and Nitrosospira multiformis ATCC 25196 T was 75.45 %, significantly lower than the value of 95 % ANI that corresponds to the 70 % species-level cut-off based on DNA-DNA hybridization. Overall polyphasic taxonomy study indicated that strain APG3 T represents a novel species in the genus Nitrosospira, for which the name Nitrosospira lacus sp. nov. is proposed (type strain

PloS one, 2014

Currently, there is no efficient therapy for patients with peripheral T cell lymphoma (PTCL). The... more Currently, there is no efficient therapy for patients with peripheral T cell lymphoma (PTCL). The Proviral Integration site of Moloney murine leukemia virus (PIM) kinases are important mediators of cell survival. We aimed to determine the therapeutic value of PIM kinases because they are overexpressed in PTCL patients, T cell lines and primary tumoral T cells. PIM kinases were inhibited genetically (using small interfering and short hairpin RNAs) and pharmacologically (mainly with the pan-PIM inhibitor (PIMi) ETP-39010) in a panel of 8 PTCL cell lines. Effects on cell viability, apoptosis, cell cycle, key proteins and gene expression were evaluated. Individual inhibition of each of the PIM genes did not affect PTCL cell survival, partially because of a compensatory mechanism among the three PIM genes. In contrast, pharmacological inhibition of all PIM kinases strongly induced apoptosis in all PTCL cell lines, without cell cycle arrest, in part through the induction of DNA damage. Therefore, pan-PIMi synergized with Cisplatin. Importantly, pharmacological inhibition of PIM reduced primary tumoral T cell viability without affecting normal T cells ex vivo. Since anaplastic large cell lymphoma (ALK+ ALCL) cell lines were the most sensitive to the pan-PIMi, we tested the simultaneous inhibition of ALK and PIM kinases and found a strong synergistic effect in ALK+ ALCL cell lines. Our findings suggest that PIM kinase inhibition could be of therapeutic value in a subset of PTCL, especially when combined with ALK inhibitors, and might be clinically beneficial in ALK+ ALCL.

Medicine, 2014

Cat-scratch disease (CSD) is the most frequent presentation of Bartonella henselae infection. It ... more Cat-scratch disease (CSD) is the most frequent presentation of Bartonella henselae infection. It has a worldwide distribution and is associated with a previous history of scratch or bite from a cat or dog. CSD affects children and teenagers more often (80%) than adults, and it usually has a self-limiting clinical course. Atypical clinical course or systemic symptoms are described in 5%-20% of patients. Among them, hepatosplenic (HS) forms (abscess) have been described. The majority of published cases have affected children or immunosuppressed patients. Few cases of HS forms of CSD in immunocompetent adult hosts have been reported, and data about the management of this condition are scarce. Herein, we present 3 new cases of HS forms of CSD in immunocompetent adults and review 33 other cases retrieved from the literature. We propose an approach to clinical diagnosis and treatment with oral azithromycin.

Molecular and cellular biochemistry, 2003