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Ibáñez D, Garcia E, Soret J, Martos J. Incipient Wear Detection of Welding Gun Secondary Circuit by Virtual Resistance Sensor Using Mahalanobis Distance. Sensors (Basel) 2023; 23:894. [PMID: 36679692 PMCID: PMC9862755 DOI: 10.3390/s23020894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 01/05/2023] [Accepted: 01/08/2023] [Indexed: 06/17/2023]
Abstract
Wear of the secondary of the welding gun, caused by mechanical fatigue or due to a bad parameterization of the welding points, causes an increase in quality problems such as non-existent welds or a reduced weld nugget size. In addition to quality problems, this defect causes production stoppages that affect the final cost of the manufactured part. Different studies have focused on evaluating the importance of different welding parameters, such as current, in the final quality of the welding nugget. However, few studies have focused on preventing weld command parameters from degrading or changing. This investigation seeks to determine the wear of the secondary circuit to avoid variability in the current supplied to the welding point caused by this defect and the increase in circuit resistance, especially in industrial environments. In this work, a virtual sensor is developed to estimate the resistance of the welding arm based on previous research, which has shown the possibility of detecting secondary wear by analysing the duty cycle of the power circuit. From the data of the virtual sensor, an anomaly detection method based on the Mahalanobis distance is developed. Finally, an integral system for detecting secondary wear of welding guns in real production lines is presented. This system establishes performance thresholds based on the analysis of the Mahalanobis distance distribution, allowing monitoring of the secondary circuit wear condition after each welding cycle. The results obtained show how the system can detect incipient wear in welding guns, regardless of which part of the secondary the wear occurs, improving decision-making and reducing quality problems.
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Affiliation(s)
- Daniel Ibáñez
- Department of Electronic Engineering, Campus de Burjassot, Universidad de Valencia, 46100 Valencia, Spain
| | - Eduardo Garcia
- Ford Spain, Poligono Industrial Ford S/N, 46440 Almussafes, Spain
| | - Jesús Soret
- Department of Electronic Engineering, Campus de Burjassot, Universidad de Valencia, 46100 Valencia, Spain
| | - Julio Martos
- Department of Electronic Engineering, Campus de Burjassot, Universidad de Valencia, 46100 Valencia, Spain
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Ibáñez D, García E, Soret J, Martos J. Real-Time Condition Monitoring System for Electrode Alignment in Resistance Welding Electrodes. Sensors (Basel) 2022; 22:8412. [PMID: 36366111 PMCID: PMC9657074 DOI: 10.3390/s22218412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 10/26/2022] [Accepted: 10/31/2022] [Indexed: 06/16/2023]
Abstract
Electrode misalignment, produced by mechanical fatigue or bad adjustments of the welding gun, leads to an increase in expulsions, deformations and quality problems of the welding joints. Different studies have focused on evaluations of the influence of a misalignment of the electrodes and the final quality of the weld nugget. However, few studies have focused on determining a misalignment of the electrodes to avoid problems caused by this defect, especially in industrial environments. In this paper, a method for performing the condition monitoring of electrode alignment degradation was developed following previous research, which has shown the relationship between the misalignment of short-circuited electrodes and the magnetic field generated by them. This method was carried out by means of a device capable of measuring the magnetic field. Finally, an integral system for the detection of misalignments in real production lines is presented. This system set behavior thresholds based on the experimentation, allowing the condition monitoring of the alignment after each welding cycle.
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Affiliation(s)
- Daniel Ibáñez
- Department of Electronic Engineering, Campus de Burjassot, Universidad de Valencia, CP 46100 Valencia, Spain
| | - Eduardo García
- Ford Spain, Poligono Industrial Ford S/N, Almussafes, CP 46440 Valencia, Spain
| | - Jesús Soret
- Department of Electronic Engineering, Campus de Burjassot, Universidad de Valencia, CP 46100 Valencia, Spain
| | - Julio Martos
- Department of Electronic Engineering, Campus de Burjassot, Universidad de Valencia, CP 46100 Valencia, Spain
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Ibáñez D, Garcia E, Soret J, Martos J. An Unsupervised Condition Monitoring System for Electrode Milling Problems in the Resistance Welding Process. Sensors (Basel) 2022; 22:4311. [PMID: 35746093 PMCID: PMC9227579 DOI: 10.3390/s22124311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 06/04/2022] [Accepted: 06/05/2022] [Indexed: 06/15/2023]
Abstract
Resistance spot welding is one of the most widely used metal joining processes in the manufacturing industry, used for structural body manufacturing, railway vehicle construction, electronics manufacturing, battery manufacturing, etc. Due to its wide use, the quality of welded joints is of great importance to the manufacturing industry, as it is critical for ensuring the integrity of finished products, such as car bodies, that withstand high levels of stress. The quality of the welding is influenced both by the programming of the welding and by the good condition of the mechanical part that carries out the welding. These mechanical factors, such as electrode geometry and wear, degrade over time. As the welding points are made, the geometry and properties of the electrodes change, so they undergo a milling process to remove impurities and return them to their initial geometry. Sometimes the milling is deficient, and the electrode continues to wear, causing welding problems such as loose spots and metal spatter. This article presents a method for condition monitoring of the milling process and weld wear based on existing data in real production lines. The use of unsupervised clustering methods is proposed to perform a check by which, using current and resistance data, the electrode wear is grouped. Specifically, a method using multidimensional k-means for the condition monitoring of electrode wear is established. This research gives a real and applicable solution for reducing the quality problems caused by milling defects and electrode wear in the production lines of high-production manufacturing industries, presenting a system for sending alarms based on the behavior of welding variables.
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Affiliation(s)
- Daniel Ibáñez
- Department of Electronic Engineering, Universidad de Valencia, Campus de Burjassot, 46100 Burjassot, Spain; (J.S.); (J.M.)
| | - Eduardo Garcia
- Ford Spain, Poligono Industrial Ford S/N, 46440 Almussafes, Spain;
| | - Jesús Soret
- Department of Electronic Engineering, Universidad de Valencia, Campus de Burjassot, 46100 Burjassot, Spain; (J.S.); (J.M.)
| | - Julio Martos
- Department of Electronic Engineering, Universidad de Valencia, Campus de Burjassot, 46100 Burjassot, Spain; (J.S.); (J.M.)
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Sanchis E, Casans S, García-Gil R, Martos J, Sanchis-Sánchez E, Pérez-Calatayud I, José Pérez-Calatayud M, Pérez-Calatayud J. Improving bleeding detector features for electron intraoperative radiotherapy. Phys Med 2019; 65:150-156. [PMID: 31473502 DOI: 10.1016/j.ejmp.2019.08.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 07/22/2019] [Accepted: 08/23/2019] [Indexed: 10/26/2022] Open
Abstract
PURPOSE The aim of this work is to improve the potential bleeding detection during intraoperative radiotherapy with linac polymethyl methacrylate applicators (PMMA), based on one previously developed. The improvements carried out have been focused on: i) minimizing the impact of the detector on the visual through the plastic applicators and ii) avoiding the asymmetry in the detection capability when the applicator is tilted. METHODS Simulations have been made to select the geometry that provides a reduced visual impact on the applicator as well as allowing an independent response with the tilting angle of the applicator. A low-noise circuit for signal conditioning has been developed. Measurements have been made on three setups: 10 cm, 7 cm and 4 cm applicator diameters, 0° and 45° tilted. RESULTS The detector has a visibility through the applicator greater than 50%. Due to the geometry, optimal detection is ensured regardless of its orientation when the applicator is tilted. It is possible to detect the presence of fluid well below the typical perturbing fluid depth established by the clinic (1-1.5 cm). CONCLUSIONS The detector can distinguish the presence of around 0.5 cm of fluid depth while showing a high visual field through the PMMA applicators and providing a measure that does not depend on the detector orientation when the applicator is tilted. The prototype is ready for its industrialization by embedding it into the applicator for clinical use. The detector would have a significant impact on both the quality assurance and the outcome of the treatment.
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Affiliation(s)
- Enrique Sanchis
- Department of Electronic Engineering, University of Valencia, E-46100, Spain; IRIMED Joint Research Unit (IIS La Fe - UV), Valencia, Spain.
| | - Silvia Casans
- Department of Electronic Engineering, University of Valencia, E-46100, Spain
| | - Rafael García-Gil
- Department of Electronic Engineering, University of Valencia, E-46100, Spain
| | - Julio Martos
- Department of Electronic Engineering, University of Valencia, E-46100, Spain
| | - Enrique Sanchis-Sánchez
- Department of Physical Therapy, University of Valencia, E-46010, Spain; IRIMED Joint Research Unit (IIS La Fe - UV), Valencia, Spain
| | | | | | - José Pérez-Calatayud
- Department of Radiation Oncology, La Fe Polytechnic and University Hospital, Valencia E-46026, Spain; IRIMED Joint Research Unit (IIS La Fe - UV), Valencia, Spain
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Inzitari M, Ruiz D, Martos J, Santaeugenia S. "Move on Against Frailty": Time to Raise Awareness about Frailty and Prevention of Disability in the Community. J Frailty Aging 2016; 5:201-203. [PMID: 27883165 DOI: 10.14283/jfa.2016.114] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Frailty, a state of increased risk of progression towards disability, with particular vulnerability to internal or external stressors, is highly prevalent among older community-dwellers, and, together with disability, represents a burden for both older adults and the society. These reasons, in aging populations, place frailty in the public health agenda (1, 2).
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Affiliation(s)
- M Inzitari
- Marco Inzitari, MD, PhD, Parc Sanitari Pere Virgili, C Esteve Terradas 30, Ed Montseny, 08023 Barcelona, Spain,
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Abstract
The aim of this study was to report a clinical case of moderate fluorosis spots treated with infiltration of low-viscosity resin. A commercial resin was applied to the facial surfaces on the anterior teeth in both the maxillary and mandibular arches. The white spots of fluorosis lost their whitish appearance and appeared similar to sound enamel. This technique, which might constitute an alternative to white-masking of fluorosis spots, showed optimal esthetic results.
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Calatayud A, Remón L, Martos J, Furlan WD, Monsoriu JA. Imaging quality of multifocal intraocular lenses: automated assessment setup. Ophthalmic Physiol Opt 2013; 33:420-6. [DOI: 10.1111/opo.12063] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2012] [Accepted: 03/17/2013] [Indexed: 11/28/2022]
Affiliation(s)
- Arnau Calatayud
- Centro de Tecnologías Físicas; Universitat Politècnica de València; Valencia; Spain
| | - Laura Remón
- Centro de Tecnologías Físicas; Universitat Politècnica de València; Valencia; Spain
| | - Julio Martos
- Departamento de Ingeniería Electrónica; Universitat de València; Burjassot; Spain
| | - Walter D Furlan
- Departamento de Óptica; Universitat de València; Burjassot; Spain
| | - Juan A Monsoriu
- Centro de Tecnologías Físicas; Universitat Politècnica de València; Valencia; Spain
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Martos J, Bilbao E, Cancio I. Regulation of hypoxia and xenobiotic exposure related genes in fish (Chelon labrosus) and mussels (Mytilus galloprovincialis) held under acute hypoxic conditions. Comp Biochem Physiol A Mol Integr Physiol 2012. [DOI: 10.1016/j.cbpa.2012.05.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Martos J, Montero Á, Torres J, Soret J, Martínez G, García-Olcina R. Novel wireless sensor system for dynamic characterization of borehole heat exchangers. Sensors (Basel) 2011; 11:7082-94. [PMID: 22164005 PMCID: PMC3231679 DOI: 10.3390/s110707082] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/02/2011] [Revised: 07/01/2011] [Accepted: 07/01/2011] [Indexed: 11/16/2022]
Abstract
The design and field test of a novel sensor system based in autonomous wireless sensors to measure the temperature of the heat transfer fluid along a borehole heat exchanger (BHE) is presented. The system, by means of two special valves, inserts and extracts miniaturized wireless sensors inside the pipes of the borehole, which are carried by the thermal fluid. Each sensor is embedded in a small sphere of just 25 mm diameter and 8 gr weight, containing a transceiver, a microcontroller, a temperature sensor and a power supply. A wireless data processing unit transmits to the sensors the acquisition configuration before the measurements, and also downloads the temperature data measured by the sensor along its way through the BHE U-tube. This sensor system is intended to improve the conventional thermal response test (TRT) and it allows the collection of information about the thermal characteristics of the geological structure of subsurface and its influence in borehole thermal behaviour, which in turn, facilitates the implementation of TRTs in a more cost-effective and reliable way.
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Affiliation(s)
- Julio Martos
- Department of Electronic Engineering, Universidad de Valencia, Campus de Burjassot, CP 46100 Valencia, Spain
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +34-963-544-025; Fax: +34-963-544-353
| | - Álvaro Montero
- Instituto de Ingeniería Energética, Universidad Politécnica de Valencia, Campus de Vera, CP 46022 Valencia, Spain; E-Mail:
| | - José Torres
- Department of Electronic Engineering, Universidad de Valencia, Campus de Burjassot, CP 46100 Valencia, Spain; E-Mails: (J.T.); (J.S.); (G.M.); (R.G.-O.)
| | - Jesús Soret
- Department of Electronic Engineering, Universidad de Valencia, Campus de Burjassot, CP 46100 Valencia, Spain; E-Mails: (J.T.); (J.S.); (G.M.); (R.G.-O.)
| | - Guillermo Martínez
- Department of Electronic Engineering, Universidad de Valencia, Campus de Burjassot, CP 46100 Valencia, Spain; E-Mails: (J.T.); (J.S.); (G.M.); (R.G.-O.)
| | - Raimundo García-Olcina
- Department of Electronic Engineering, Universidad de Valencia, Campus de Burjassot, CP 46100 Valencia, Spain; E-Mails: (J.T.); (J.S.); (G.M.); (R.G.-O.)
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Martos J, Bassotto APS, González-Rodríguez MP, Ferrer-Luque CM. Dissolving efficacy of eucalyptus and orange oil, xylol and chloroform solvents on different root canal sealers. Int Endod J 2011; 44:1024-8. [PMID: 21658077 DOI: 10.1111/j.1365-2591.2011.01912.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
AIM To evaluate the solubility of five root canal sealers in orange oil, eucalyptol, xylol and chloroform solvents. METHODOLOGY The solubility of RoekoSeal, Sealer 26, Epiphany, Endomethasone and EZ-Fill sealers was assessed in orange oil, eucalyptol, xylol, chloroform and distilled water. Seventy-five samples of root canal sealers were prepared and then divided into five groups for immersion in solvent for 2, 5 or 10 min. The means of loss weight were determined for each material in each solvent at all immersion periods, and the values were compared by factorial analysis of variance (anova) and SNK multiple comparisons. RESULTS In the orange and eucalyptus oil groups, there was no significant difference among RoekoSeal, Sealer26, Epiphany and EZ-Fill at the three immersion periods (P > 0.05). With xylol, no significant differences were found at 5 and 10 min (P > 0.05) for each root sealer. Orange and eucalyptus oil solvents were as effective as chloroform at 2 min in dissolving all the root sealers. CONCLUSIONS Xylol was the most effective solvent followed by the chloroform and the essential oils (eucalyptol and orange oil). Orange oil behaved in a similar way to eucalyptus oil.
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Affiliation(s)
- J Martos
- Department of Semiology and Clinic, Faculty of Dentistry, Federal University of Pelotas, Pelotas, RS, Brazil.
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Martos J, Ferrer-Luque CM, González-Rodríguez MP, Castro LAS. Topographical evaluation of the major apical foramen in permanent human teeth. Int Endod J 2009; 42:329-34. [DOI: 10.1111/j.1365-2591.2008.01513.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Falco C, Alvarez O, Castillo I, Estevan I, Martos J, Mugarra F, Iradi A. Influence of the distance in a roundhouse kick's execution time and impact force in Taekwondo. J Biomech 2009; 42:242-8. [PMID: 19124126 DOI: 10.1016/j.jbiomech.2008.10.041] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2008] [Revised: 10/06/2008] [Accepted: 10/28/2008] [Indexed: 11/17/2022]
Abstract
Taekwondo, originally a Korean martial art, is well known for its kicks. One of the most frequently used kicks in competition is Bandal Chagui or roundhouse kick. Excellence in Taekwondo relies on the ability to make contact with the opponent's trunk or face with enough force in as little time as possible, while at the same time avoiding being hit. Thus, the distance between contestants is an important variable to be taken into consideration. Thirty-one Taekwondo athletes in two different groups (expert and novice, according to experience in competition) took part in this study. The purpose of this study was to examine both impact force and execution time in a Bandal Chagui or roundhouse kick, and to explore the effect of execution distance in these two variables. A new model was developed in order to measure the force exerted by the body on a load. A force platform and a contact platform were used to measure these variables. The results showed that there are no significant differences in terms of impact force in relation to execution distance in expert competitors. Significant and positive correlations between body mass and impact force (p<.01) seem to mean that novice competitors use their body mass to generate high impact forces. Significant differences were found in competitive experience and execution time for the three different distances of kicking considered in the study. Standing at a certain further distance from the opponent should be an advantage for competitors who are used to kick from a further distance in their training.
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Affiliation(s)
- Coral Falco
- Catholic University of Valencia, Faculty of Physical Activity and Sport Sciences, c/Guillem de Castro, 94, 46003 Valencia, Spain.
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Orellana C, Peña F, García A, Perea J, Martos J, Domenech V, Acero R. Carcass characteristics, fatty acid composition, and meat quality of Criollo Argentino and Braford steers raised on forage in a semi-tropical region of Argentina. Meat Sci 2009; 81:57-64. [DOI: 10.1016/j.meatsci.2008.06.015] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2007] [Revised: 05/16/2008] [Accepted: 06/18/2008] [Indexed: 10/21/2022]
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Liang Y, Woodward DF, Guzman VM, Li C, Scott DF, Wang JW, Wheeler LA, Garst ME, Landsverk K, Sachs G, Krauss AHP, Cornell C, Martos J, Pettit S, Fliri H. Identification and pharmacological characterization of the prostaglandin FP receptor and FP receptor variant complexes. Br J Pharmacol 2008; 154:1079-93. [PMID: 18587449 PMCID: PMC2440084 DOI: 10.1038/bjp.2008.142] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Background and purpose: A prostamide analogue, bimatoprost, has been shown to be effective in reducing intraocular pressure, but its precise mechanism of action remains unclear. Hence, to elucidate the molecular mechanisms of this effect of bimatoprost, we focused on pharmacologically characterizing prostaglandin FP receptor (FP) and FP receptor variant (altFP) complexes. Experimental approach: FP receptor mRNA variants were identified by reverse transcription-polymerase chain reaction. The FP-altFP4 heterodimers were established in HEK293/EBNA cells co-expressing FP and altFP4 receptor variants. A fluorometric imaging plate reader was used to study Ca2+ mobilization. Upregulation of cysteine-rich angiogenic protein 61 (Cyr61) mRNA was measured by Northern blot analysis, and phosphorylation of myosin light chain (MLC) by western analysis. Key results: Six splicing variants of FP receptor mRNA were identified in human ocular tissues. Immunoprecipitation confirmed that the FP receptor is dimerized with altFP4 receptors in HEK293/EBNA cells co-expressing FP and altFP4 receptors. In the studies of the kinetic profile for Ca2+ mobilization, prostaglandin F2α (PGF2α) elicited a rapid increase in intracellular Ca2+ followed by a steady state phase. In contrast, bimatoprost elicited an immediate increase in intracellular Ca2+ followed by a second phase. The prostamide antagonist, AGN211335, selectively and dose-dependently inhibited the bimatoprost-initiated second phase of Ca2+ mobilization, Cyr61 mRNA upregulation and MLC phosphorylation, but did not block the action of PGF2α. Conclusion and implications: Bimatoprost lacks effects on the FP receptor but may interact with the FP-altFP receptor heterodimer to induce alterations in second messenger signalling. Hence, FP-altFP complexes may represent the underlying basis of bimatoprost pharmacology.
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Affiliation(s)
- Y Liang
- Departments of Biological and Chemical Sciences, Allergan Inc., Irvine, CA, USA.
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García A, Perea JM, Mayoral A, Acero R, Martos J, Gómez G, Peña F. Laboratory rearing conditions for improved growth of juvenile Helix aspersa Müller snails. Lab Anim 2006; 40:309-16. [PMID: 16803649 DOI: 10.1258/002367706777611505] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
A laboratory rearing system in semi-controlled conditions is proposed to facilitate the behavioural rhythms of the edible snail (Helix aspersa) and to produce a high growth rate with low variability. The growth data were used to construct a model for weight estimation based on age. The animals' live weights showed low variability (<17%) and normal distribution. The best model for estimating weight from age is the logistic model, with a high corelation coefficient (>90%), and a high level of significance for the coefficient (P < 0.0001).
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Affiliation(s)
- A García
- Animal Science Department, Campus of Rabanales, University of Córdoba, Córdoba, Spain.
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Martos J, Gastal MT, Sommer L, Lund RG, Del Pino FAB, Osinaga PWR. Dissolving efficacy of organic solvents on root canal sealers. Clin Oral Investig 2005; 10:50-4. [PMID: 16317555 DOI: 10.1007/s00784-005-0023-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2004] [Accepted: 10/25/2005] [Indexed: 11/28/2022]
Abstract
The aim of this study was to evaluate the solubility of three types of root canal sealers in three organic solvents used in endodontics. The solubility of calcium-hydroxide-based (Sealer 26), silicon-polydimethylsiloxane-based (RoekoSeal), and zinc-oxide-eugenol based (Endofill and Intrafill) sealers was assessed in eucalyptol, xylol, orange oil, and distilled water. Eighty samples of each filling material were prepared according to the manufacturers' instructions and then divided into four groups for immersion in solvent for 2 or 10 min. The means of sealer dissolution in solvents were obtained by the difference between the original preimmersion weight and the postimmersion weight in a digital analytical scale. Data were statistically analyzed with the Student's t test, and multiple comparisons were performed with Student-Newman-Keuls. Xylol and orange oil showed similar effects, with significant solubilization (P<0.05) of the tested cements. Endofill and Sealer 26 did not show any significant difference in solubilization at the two immersion times, whereas RoekoSeal and Intrafill showed a more pronounced solubility at 10 min. The lowest levels of solubilization occurred in RoekoSeal, Sealer 26, Endofill, and Intrafill. It is concluded that xylol and orange oil presented similar solvent effects with a significant solubility of the tested cements.
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Affiliation(s)
- J Martos
- Department of Clinics, Pelotas Dental School, Federal University of Pelotas, Rua Gonçalves Chaves 457, 96015-560 Pelotas, Rio Grande do Sul, Brazil.
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Martos J, Ayuda R. [Communication and language in the autistic spectrum: autism and dysphasia]. Rev Neurol 2002; 34 Suppl 1:S58-63. [PMID: 12447791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/27/2023]
Abstract
INTRODUCTION The alterations of language and communication seen in children with autistic spectrum disorders (TEA) have some similar and some dissimilar features to those seen in children with specific language disorders (TEL). The basic disorder of TEA seems to be due to alterations in the social and mental use of codes of communication, both verbal and non verbal. Children with TEL however have better non verbal and practical abilities. OBJECTIVE In view of this, we decided to determine the qualitative difference in function in communication and language between the two populations. PATIENTS AND METHODS The great heterogeneity between persons with autistic spectrum disorders and even variation between individuals makes investigation of large groups difficult. It is therefore necessary to study individual cases or groups with small numbers. If we fix our attention on language and communication, it is important to define subtypes of function with the population affected by the autistic spectrum of disorders at an early age, in the fields of communication, receptive language and expressive language in our small sample of persons; taking the normal course of development in each field as the parameter for comparison. This is a pilot study within a long term research project. RESULTS The results reported here are the preliminary findings of what will be a more extensive study with fuller analysis of the results. CONCLUSIONS The preliminary findings suggest that there are different linguistic and communication function profiles in the different populations compared.
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Affiliation(s)
- J Martos
- DELETREA (Diagnóstico, Evaluación del Lenguaje y Tratamiento del Espectro Autista), Madrid, Spain.
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Piva E, Martos J, Demarco FF. Microleakage in amalgam restorations: influence of cavity cleanser solutions and anticariogenic agents. Oper Dent 2001; 26:383-8. [PMID: 11504438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
This study evaluated in vitro the influence of five solutions used to treat cavity preparations on microleakage of amalgam restorations. Seventy-two standard Class V cavities were prepared in buccal and lingual surfaces of 36 recently extracted human third molars. The cervical wall was located in cementum and the occlusal wall was located in enamel. Specimens were randomly divided into six groups (n=12) according to the solution employed to treat the cavities: Group I-2.5% sodium hypochlorite; Group II-Calcium hydroxide solution; Group III-1.23% Acidulated phosphate fluoride; Group IV-2% digluconate of chlorhexidine; Group V-anionic detergent solution (1.25% sodium lauryl sulfate) and Group VI-control group. The solutions were applied for one minute, followed by washing and drying. Two coats of copal varnish were applied in each cavity. The cavities were filled with capsuled amalgam GS-80 (SDI). After finishing and polishing, the specimens were submitted for thermal cycling followed by immersion in methylene blue. Then, the specimens were sectioned and microleakage was evaluated based on a standard ranking under magnification (40x). Data were subjected to statistical analysis using non-parametric tests. Results of the study concluded that leakage was higher in cementum than enamel (p<0.01). The substances employed have no influence on microleakage except for sodium hypochlorite, which increased leakage values in enamel (p<0.05).
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Affiliation(s)
- E Piva
- Federal University of Pelotas, School of Dentistry, Department of Operative Dentistry, Pelotas-RS, Brazil
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Schabet M, Martos J, Buchholz R, Pietsch T. Animal model of human medulloblastoma: clinical, magnetic resonance imaging, and histopathological findings after intra-cisternal injection of MHH-MED-1 cells into nude rats. Med Pediatr Oncol 1997; 29:92-7. [PMID: 9180909 DOI: 10.1002/(sici)1096-911x(199708)29:2<92::aid-mpo5>3.0.co;2-m] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
To establish an animal model of human medulloblastoma, we have injected human MHH-MED-1 cells into the cisterna magna of nude rats. Tumors grew in 3 out of 4 animals injected with 10(6) medulloblastoma cells. Affected animals showed little or no weight gain and eventually lost weight but did not develop obvious neurological symptoms until the end of observation on day 31 after inoculation. At this time, magnetic resonance imaging (MRI) in tumor-bearing rats revealed contrast enhancement in the region of the fourth ventricle and the cisterna magna. Neuropathological examination demonstrated corresponding leptomeningeal growth in the cisterna magna invading the medulla oblongata, and tumor growth within the fourth ventricle invading the pons. The tumors basically showed the same immunostaining pattern as MHH-MED-1 cells in vitro expressing neuron-specific enolase (NSE) and vimentin, but no neurofilaments (NFs), synapthophysin, or glial fibrillary acidic protein (GFAP). No tumor grew in the fourth animal, which had a normal weight gain and no alteration on MRI. In conclusion (1) the intrathecally injected human medulloblastoma cells spread similar to medulloblastomas in patients, (2) tumor growth is readily detected by MRI, (3) the new animal model is a suitable tool for further experimental research including intrathecal therapeutic studies.
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Affiliation(s)
- M Schabet
- Department of Neurology, University of Tübingen, Germany
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Abstract
This study addressed the use of 3D MR angiography with flip angles (FAs) linearly varying across the excitation volume in order to diminish spin saturation. The shape of the ramp profile was varied to optimize the method for different regions and pathological alterations. Radio frequency pulses with ramp-shaped excitation profiles were generated using Fourier transformation and integrated into a flow-compensated 3D-FISP sequence. With the use of ramp-shaped excitation profiles good results were obtained for intracranial arteries as well as for neck arteries (i.e. carotid and vertebral arteries) which were demonstrated in 6 healthy volunteers and in 5 patients with various stenoses and anomalies of the carotid and vertebral arteries. With this technique it was possible to use increased thicknesses of the excitation volume (slab) up to 256 mm. Ramp-shaped excitation pulses with linearly increasing FAs in main flow direction can provide improved contrast of the vessel parts located distally to the entry side of the slab. Although this method has no advantage concerning complex flow or other dephasing effects; its particular effectiveness lies in the reduction of spin saturation.
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Affiliation(s)
- J Martos
- National Institute of Neurosurgery, Budapest, Hungary
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Abstract
Maximum intensity projection (MIP), the commonly used technique for calculating MR-angiograms from three-dimensional (3D) datasets, often fails to visualize small vessels due to superposition of background signal. An improved vascular depiction can be reached by application of a connectivity algorithm, but a very good delimitation of vessel signals from signals of stationary tissue is required for this technique. Results of intracranial vessel tracking could be improved by a 3D interpolation and a preceding highpass filtering of the 3D image dataset.
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Affiliation(s)
- U Klose
- Department of Neuroradiology, University of Tübingen, Germany
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22
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Abstract
Spin saturation effects in 3D time-of-flight (TOF) MR angiography (MRA) can be reduced by using radio-frequency (RF) pulses with linearly increasing flip angles (ramp pulses) in the main direction of flow. MR angiograms of the cervical arteries of five healthy volunteers and eleven patients suffering from stenosis of the internal carotid arteries were acquired using a standard flow-compensated 3D FISP sequence with a single volume technique. Compared with the conventional MR angiograms acquired with constant flip angles, the MR angiograms could be considerably improved using the ramp pulses. Especially the distal parts of the vessels were depicted more clearly due to significantly reduced saturation effects. Since the vessel signal largely depends on the shape of the ramp pulses, we developed a model for calculating the signal distribution of the flowing protons for different ramp shapes and a given excitation volume (slab). The calculated signals were largely consistent with the signals in the MR angiograms, thus permitting numerical optimization of the shape of the ramp pulses for the cervical arteries. This optimized shape of the ramp pulse provided a high homogeneous vessel signal across the slab.
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Affiliation(s)
- T Nägele
- Abteilung für Neuroradiologie, Radiologische Klinik, Universität Tübingen
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Abstract
OBJECTIVE To determine the serum levels of FSH, LH, PRL, estradiol, progesterone and testosterone in umbilical vein blood in a group of normal neonates. METHOD Umbilical vein blood was obtained for serum analyses from 52 newborns (25 females and 27 males) in the Maternity of the Hospital Regional Virgen de las Nieves, Granada (Spain) and means were compared with Student's t-test. RESULT Mean values of prolactin, estradiol and progesterone were similar in both sexes. The levels of gonadotropins in umbilical vein blood found were significantly higher in newborn males than in females (P < 0.001 for LH, P < 0.007 for FSH). Testosterone levels were higher in male neonates than in females (P < 0.004). CONCLUSION Our data reflect the dynamic state of male fetal endocrinological status in comparison to female fetuses, and strongly suggest that the mechanisms of hormonal regulation differ in the two sexes.
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Affiliation(s)
- A J Herruzo
- Department of Obstetrics and Gynecology, Virgen de las Nieves Regional Hospital, Granada, Spain
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Nägele T, Petersen D, Klose U, Grodd W, Opitz H, Gut E, Martos J, Voigt K. Dynamic contrast enhancement of intracranial tumors with snapshot-FLASH MR imaging. AJNR Am J Neuroradiol 1993; 14:89-98. [PMID: 8427115 PMCID: PMC8334446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
PURPOSE To investigate whether exact evaluation of the dynamic contrast enhancement pattern within intracranial tumors can help to classify tumor histology and vascularity. METHOD Forty-nine patients suffering from different intra- and extraaxial intracranial tumors underwent MR-examination in a 1.5-T superconductive whole body system. After rapid injection of Gd-DTPA, 48 images were acquired during the first 1.5 to 2 minutes of contrast enhancement within the tumors. A fast snapshot-FLASH imaging technique allowed measurement times of 1 second per image. Appearance of Gd-DTPA in a venous sinus served as a temporal reference point. Transformation of 48 discrete measurement points (mean signal values of the enhancing tumor region) into a continuous curve, using a cubic spline approximation, allowed calculation of the time of maximum signal increase (Tm1) and the following time of half maximum increase (Tm2). These time parameters were compared to histopathologic findings, especially the degree of tumor vascularization. RESULTS Significantly different dynamic patterns of the early enhancement period were found for the different tumors. All eight neurinomas, typically less vascularized than most meningiomas, showed a characteristically prolonged contrast enhancement with a long Tm2. Histopathologic findings concerning the degree of vascularization showed two subtypes in meningiomas (n = 17) as well as in pituitary macroadenomas (n = 7). This was confirmed by dynamic evaluation in all cases, in the sense that short Tm1 and Tm2 were found in cases with higher degrees of vascularization. Negatives values of Tm1 were measured in two glomus jugulare tumors, reflecting the arterialization of these vascular tumors. In neuroepithelial tumors (n = 15), the glioblastomas (n = 7) showed very short Tm1 compared to the lower grade gliomas (n = 8). This is explained by histologic findings of pathologic vessels with arteriovenous shunts. CONCLUSION The evaluated dynamic time parameters can be used to narrow differential diagnostic possibilities and to infer the degree of vascularization of intracranial tumors.
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Affiliation(s)
- T Nägele
- Abteilung für Neuroradiologie, Universität Tübingen, Germany
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Martos J, Petersen D, Klose U, Requardt H, Buchholz R, Ohneseit P, Schabet M, Voigt K. MR imaging of experimental meningeal melanomatosis in nude rats. J Neurooncol 1992; 14:207-11. [PMID: 1460485 DOI: 10.1007/bf00172596] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
MR imaging of the rat brain has become an increasingly frequently used method in experimental neuroradiology. On a generally available 1.5 T whole body tomograph, supplemented with an individually made small coil and a special SE sequence we obtained fairly fine images of the structures of the rat brain. With gadolinium-DTPA, we were able to visualize posterior fossa and cervical leptomeningeal growth of intrathecally injected B16 melanoma in nude rats. Using MRI to follow experimental leptomeningeal metastasis, may provide a new means for diagnostic evaluation and preclinical testing of treatment modalities.
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Affiliation(s)
- J Martos
- Department of Neuroradiology, University of Tübingen, Germany
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Martos J, Bohár L, Fekete G. [Three-dimensional CT studies of pelvic fractures]. Magy Traumatol Orthop Helyreallito Seb 1992; 35:116-9. [PMID: 1363601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 03/25/2023]
Abstract
Authors use in the diagnosis of fractures of the pelvis a three dimension programme developed by them to the tomographic apparatus of the Siemens Somatom CR computer. With the demonstration of a few pictures of their own they call attention to the possibility of diagnosis given by the 3D-CT programme. On the basis of their experiences the advantages and disadvantages of this modern imaging method are summarized.
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Affiliation(s)
- J Martos
- Országos Idegsebészeti Tudományos Intézet és Országos Traumatológiai Intézet közleménye
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Abstract
The boundaries of subnuclei of the hypothalamic paraventricular nucleus (PVN) were outlined on the basis of a step by step computer-assisted image analysis of coronal, serial sections of the hypothalamus in rats. The cell size-frequency histogram, cell packing density, and the cell number were determined for each PVN subdivision. Three principal cell types were distinguished: small, short diameter (d) = 6-10 microns; medium-sized, d = 10-13 microns; and large, d = 13-19 microns. None of these cell types occur exclusively in any PVN subdivision. According to the predominant cell type, the PVN can be divided into magnocellular, mediocellular and parvicellular subnuclei. Large cells appear to form one subdivision in which the cell packing density is relatively stable. Although the cell sizes showed a relatively large variation, no definitive subgroups (parts) could be distinguished. On the basis of cell packing density, the parvicellular and mediocellular subnuclei can be further divided. The mediocellular cell group can be divided into a dorsal and a posterior subdivision. The parvicellular zone is subdivided into a periventricular and a large medial subdivision. Based on inhomogeneities in cell packing density, the medial subdivision can be further divided into anterior, dorso-lateral, ventromedial and caudal parts. The estimated total cell number in the PVN (in both sides of the brain) is about 21,500. On average, 19% of this population, i.e., 4,200 neurons, was calculated in the magnocellular (neurosecretory) division. Out of this, only 66%, about 2,700 cells, falls into the category of large cells. There are approximately 5,700 neurons in the posterior and dorsal mediocellular, and about 11,600 in the periventricular and medial parvicellular subdivisions.
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Affiliation(s)
- J Z Kiss
- Institute of Histology and Embryology, University of Geneva Medical School, Switzerland
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Abstract
An analytical, recursive method has been developed to demonstrate the anisotropic electrotonic geometry of nerve cells containing varicose or spiny dendrites. The procedure has been based on the distribution of the core geometry of dendrites into modules which consist of module elements where the physical length is much shorter than the actual space constant. The unambiguous representation of the anisotropic core geometry has been possible by plotting the decomposed geometries separated under the condition of the unidirectional spread of the wave front of dendritic potentials. This decomposition has revealed the bidirectional, "smoothed" core geometries as a function of irregular distribution of varicosities or spines. The shape of decomposed core geometries may change according to the position of the input site. The shaping of core geometry reflects the electrotonic effectiveness of a synaptic site to any arbitrary locations which may lead to considerable savings in computations on synaptic effects. The detailed, computer-reconstructed geometry of the apical dendritic field of the pyramidal cell has been analysed by the proposed method. The frequency-dependence of input impedances has been compared between the original and the transformed core geometries assuming that the current is injected into the soma. The significance of dendritic irregularities in the impedance matching has been studied when the shaping of the core geometry has been induced by laminar inputs. The proposed approach may be useful in comparing the input dependence of the receptive fields of different non-smooth cells. The mismatch of the core geometries induced by the opposite travelling waves from the same anatomical location has also been studied and the possible control of the preferred, direction-sensitive activities will be discussed. The important differences between the compartmental modelings based on the known isotropic treatment of dendrites and the more realistic anisotropic approach will be illustrated.
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Affiliation(s)
- F Pongrácz
- 2nd Department of Anatomy, Semmelweis University Medical School, Budapest, Hungary
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Muñoz M, Díaz J, Escobar Jiménez F, Morales I, Vara C, Mantas JA, Martos J. [Localization of the parathyroid glands]. Rev Clin Esp 1988; 182:203-5. [PMID: 3045906] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Ruíz de Almodovar JM, Olea N, Padilla O, Sampere JM, Martos J, Pedraza V. [Endemic goiter. Consideration on its etiology]. Rev Clin Esp 1980; 157:433-7. [PMID: 7414038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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Salvatierra D, Martos J, De la Higuera J. [New prospects in antirheumatic therapy. Joint scanning with radioisotopes]. Minerva Med 1973; 64:2410-1. [PMID: 4723568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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