22 results on '"Matos JN"'
Search Results
2. Cystic meningioma.
- Author
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Barriel LME, Cruz JJG, Martín RAJ, Castillo MCR, and Matos JN
- Abstract
Copyright of Archivos de Neurociencias is the property of Instituto Nacional de Neurologia y Neurocirugia, Departamento de Publicaciones Cientificas and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2009
3. Cats with diabetes mellitus have diastolic dysfunction in the absence of structural heart disease
- Author
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M. Baron Toaldo, N.J. Pereira, U. Bartoszuk, J. Novo Matos, Toni M Glaus, Claudia E Reusch, N. Summerfield, A Riederer, Pereira, NJ, Matos, JN, Baron Toaldo, M, Bartoszuk, U, Summerfield, N, Riederer, A, Reusch, C, Glaus, TM, University of Zurich, and Glaus, Toni M
- Subjects
medicine.medical_specialty ,10253 Department of Small Animals ,Diastolic function ,Heart disease ,040301 veterinary sciences ,Diabetic Cardiomyopathies ,3400 General Veterinary ,Tissue doppler imaging ,Diastole ,CatsDiabetes mellitusDiastolic functionEchocardiographyTissue doppler imaging ,Newly diagnosed ,030204 cardiovascular system & hematology ,Cat Diseases ,0403 veterinary science ,03 medical and health sciences ,0302 clinical medicine ,Internal medicine ,Diabetes mellitus ,medicine ,Diabetes Mellitus ,Animals ,Prospective cohort study ,CATS ,General Veterinary ,630 Agriculture ,business.industry ,04 agricultural and veterinary sciences ,medicine.disease ,Echocardiography ,Heart failure ,Cardiology ,Cats ,570 Life sciences ,biology ,Animal Science and Zoology ,1103 Animal Science and Zoology ,business - Abstract
Diabetes mellitus (DM) can result in cardiovascular dysfunction and heart failure characterized by diastolic dysfunction with or without the presence of systolic dysfunction in people and laboratory animals. The objective of this prospective study was to determine if cats with newly diagnosed DM had myocardial dysfunction and, if present, whether it would progress if appropriate antidiabetic therapy was commenced. Thirty-two diabetic cats were enrolled and received baseline echocardiographic examination; of these, 15 cats were re-examined after 6 months. Ten healthy age- and weight-matched cats served as controls. Diabetic cats at diagnosis showed decreased diastolic, but not systolic function, when compared to healthy controls, with lower mitral inflow E wave (E) and E/E' than controls. After 6 months, E and E/IVRT' decreased further in diabetic cats compared to the baseline evaluation. After excluding cats whose DM was in remission at 6 months, insulin-dependent diabetic cats had lower E, E/A and E' than controls. When classifying diastolic function according to E/A and E'/A', there was shift towards impaired relaxation patterns at 6 months. All insulin-dependent diabetic cats at 6 months had abnormal diastolic function. These results indicate that DM has similar effects on diastolic function in feline and human diabetics. The dysfunction seemed to progress rather than to normalize after 6 months, despite antidiabetic therapy. In cats with pre-existing heart disease, the development of DM could represent an important additional health risk.
- Published
- 2017
4. Low-cost, programmable oscillator operates at 2 GHz.
- Author
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Navarro, A, Rostami, M, and Matos, JN
- Subjects
- *
ELECTRIC oscillators , *INTEGRATED circuits , *ELECTRONICS , *WIRELESS communications , *DESIGN - Abstract
Describes the design of a low-cost, programmable oscillator that operates at 2 GHz. Central integrated circuit; Wireless applications.
- Published
- 2000
5. Concept and Design of a Multi-Polarization Reconfigurable Microstrip Antenna with Symmetrical Biasing Control.
- Author
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Antunes F, Ramos A, Varum T, and Matos JN
- Abstract
Wireless communication systems have grown rapidly, moving towards being highly compact, intelligent, and flexible to adapt to changing operating requirements. Multifunctional and highly versatile antennas are key in this development to ensure system quality. Reconfigurable antennas, particularly regarding polarization, allow frequency reuse and enable the mitigation of fading effects. This work presents a square microstrip patch antenna operating in the ISM 5.8 GHz band with reconfigurable polarization by controlling its feeding. This antenna has four different states through the application of a symmetrical DC voltage that controls an RF circuit with PIN diodes. As a result, the microstrip patch can operate with three different polarizations: linear polarization and both circular polarizations (right-handed and left-handed). The antenna was fabricated to validate the proposed concept. The good agreement between the measurement and the simulation results was possible to observe regarding its polarization behaviour, impedance adaptation and radiation pattern.
- Published
- 2024
- Full Text
- View/download PDF
6. Automated echocardiographic left ventricular dimension assessment in dogs using artificial intelligence: Development and validation.
- Author
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Stowell CC, Kallassy V, Lane B, Abbott J, Borgeat K, Connolly D, Domenech O, Dukes-McEwan J, Ferasin L, Del Palacio JF, Linney C, Matos JN, Spalla I, Summerfield N, Vezzosi T, Howard JP, Shun-Shin MJ, Francis DP, and Fuentes VL
- Subjects
- Dogs, Animals, Reproducibility of Results, Heart Ventricles diagnostic imaging, Diastole, Artificial Intelligence, Echocardiography veterinary, Echocardiography methods
- Abstract
Background: Artificial intelligence (AI) could improve accuracy and reproducibility of echocardiographic measurements in dogs., Hypothesis: A neural network can be trained to measure echocardiographic left ventricular (LV) linear dimensions in dogs., Animals: Training dataset: 1398 frames from 461 canine echocardiograms from a single specialist center., Validation: 50 additional echocardiograms from the same center., Methods: Training dataset: a right parasternal 4-chamber long axis frame from each study, labeled by 1 of 18 echocardiographers, marking anterior and posterior points of the septum and free wall., Validation Dataset: End-diastolic and end-systolic frames from 50 studies, annotated twice (blindly) by 13 experts, producing 26 measurements of each site from each frame. The neural network also made these measurements. We quantified its accuracy as the deviation from the expert consensus, using the individual-expert deviation from consensus as context for acceptable variation. The deviation of the AI measurement away from the expert consensus was assessed on each individual frame and compared with the root-mean-square-variation of the individual expert opinions away from that consensus., Results: For the septum in end-diastole, individual expert opinions deviated by 0.12 cm from the consensus, while the AI deviated by 0.11 cm (P = .61). For LVD, the corresponding values were 0.20 cm for experts and 0.13 cm for AI (P = .65); for the free wall, experts 0.20 cm, AI 0.13 cm (P < .01). In end-systole, there were no differences between individual expert and AI performances., Conclusions and Clinical Importance: An artificial intelligence network can be trained to adequately measure linear LV dimensions, with performance indistinguishable from that of experts., (© 2024 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals LLC on behalf of American College of Veterinary Internal Medicine.)
- Published
- 2024
- Full Text
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7. Effects of Breed, Exercise, and a Two-Month Training Period on NT-proBNP-Levels in Athletic Dogs.
- Author
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Ivasovic F, Matos JN, Wyler M, and Glaus TM
- Abstract
N-terminal pro-b-type natriuretic peptide (NTproBNP) is a cardiac biomarker used to detect myocardial wall stress. Physical activity and cardiac disease can affect serum NTproBNP concentrations. In people, different types of physical activity have different effects on NTproBNP. Our hypothesis was that physical activity and training have an effect on NTproBNP concentrations depending on the type of exercise and the intensity. Seven German Shepherd dogs (GSD) under military training performing short bursts of fast-paced interval exercise and seven Eurohounds (EHs) training for racing competition with endurance exercise were included in the study. Blood samples were taken at enrollment (T
0 ) and after a two-month (T2mth ) training period; on both occasions, the samples were acquired before and after physical exercise. An echocardiographic evaluation was performed at T0 . Echocardiographic heart size was larger in the EHs compared to the GSDs. The NTproBNP concentration was higher in the EHs than in the GSDs before and after exercise at T0 and T2mth . Echocardiographic parameters of heart size and wall thickness correlated with NTproBNP at T0 before and after exercise. Exercise induced an elevation of NTproBNP in the EHs at T0 and T2mth , while in the GSDs this was observed only at T0 . In the EHs, post exercise was associated with higher NTproBNP at T2mth compared to T0 , while in the GSDs the opposite pattern was noticed. From our study, the serum NTproBNP concentration differs between breeds. Intense physical activity causes an increase in NTproBNP. A two-month training period does not affect the NTproBNP concentration at rest. Intense physical activity may increase NTproBNP above the reference range in individual dogs.- Published
- 2022
- Full Text
- View/download PDF
8. ECG of the Month.
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Regada SF, Silva J, and Matos JN
- Subjects
- Animals, Electrocardiography veterinary
- Published
- 2022
- Full Text
- View/download PDF
9. Retrospective evaluation of hypertrophic cardiomyopathy in 68 dogs.
- Author
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Schober KE, Fox PR, Abbott J, Côté E, Luis-Fuentes V, Matos JN, Stern JA, Visser L, Scollan KF, Chetboul V, Schrope D, Glaus T, Santilli R, Pariaut R, Stepien R, Arqued-Soubeyran V, Baron Toaldo M, Estrada A, MacDonald K, Karlin ET, and Rush J
- Subjects
- Animals, Dogs, Echocardiography veterinary, Hypertrophy, Left Ventricular veterinary, Retrospective Studies, Cardiomyopathy, Hypertrophic diagnosis, Cardiomyopathy, Hypertrophic veterinary, Dog Diseases diagnostic imaging, Heart Failure veterinary, Ventricular Dysfunction, Left veterinary
- Abstract
Background: There is a lack of clinical data on hypertrophic cardiomyopathy (HCM) in dogs., Hypothesis/objectives: To investigate signalment, clinical signs, diagnostic findings, and survival in dogs with HCM., Animals: Sixty-eight client-owned dogs., Methods: Retrospective multicenter study. Medical records were searched between 2003 and 2015. The diagnosis of left ventricular (LV) hypertrophy was made by echocardiographic examination., Results: Three hundred and forty-five dogs with LV hypertrophy were identified, of which 277 were excluded. The remaining 68 dogs were 0.3 to 14 years old and predominantly <10 kg (85%), and without a sex predilection. Twenty-four % were Shih Tzu and 24% terrier breeds. Most (80%) had a systolic heart murmur. Owner-determined exercise intolerance (37%) and syncope (18%) were most commonly reported signs. The majority (84%) of dogs had symmetrical LV hypertrophy, whereas asymmetrical septal and LV free wall hypertrophy was observed in 9% and 6% of dogs, respectively. Isolated basal interventricular septal hypertrophy was not observed. Commonly recorded were systolic anterior motion of the mitral valve (60%) and LV diastolic dysfunction (89% of dogs where diastolic function was evaluated). Six dogs died unexpectedly, and 3 developed congestive heart failure. Known survival times were between 1 day and 114 months after diagnosis., Conclusions and Clinical Importance: Hypertrophic cardiomyopathy in dogs should be considered as a differential diagnosis if LV hypertrophy is identified. Small breed dogs are overrepresented, and it is uncommon for dogs with HCM to develop CHF although sudden death can occur., (© 2022 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals LLC on behalf of American College of Veterinary Internal Medicine.)
- Published
- 2022
- Full Text
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10. Anterior mitral valve leaflet length in cats with hypertrophic cardiomyopathy.
- Author
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Seo J, Matos JN, Payne JR, Fuentes VL, and Connolly DJ
- Subjects
- Animals, Cats, Echocardiography veterinary, Longitudinal Studies, Mitral Valve diagnostic imaging, Retrospective Studies, Cardiomyopathy, Hypertrophic diagnostic imaging, Cardiomyopathy, Hypertrophic veterinary, Cat Diseases diagnostic imaging
- Abstract
Introduction: Anterior mitral valve leaflet (AMVL) elongation is a recognised feature of hypertrophic cardiomyopathy (HCM). However, whether AMVL elongation precedes left ventricular hypertrophy in cats is currently unknown. The aim of this study was to explore the risk of developing an HCM phenotype in cats with an elongated AMVL., Animals: FIFTY-FIVE APPARENTLY HEALTHY CATS WITH A NORMAL BASELINE ECHOCARDIOGRAM AND A FOLLOW-UP ECHOCARDIOGRAM AT >ONE YEAR., Materials and Methods: This was a retrospective longitudinal study. Cats at the baseline were grouped based on whether or not they developed an HCM phenotype at follow-up. AMVL length and left atrial and left ventricular dimensions were measured from two-dimensional images., Results: The median follow-up period of the study population was 5.4 years (25th and 75th quartile, 2.7-6.7 years). During this time, 17 cats (30.9%) developed an HCM phenotype. At the baseline, cats that subsequently developed an HCM phenotype had greater AMVL length (9.4 mm [25th and 75th quartile, 9.0-10.6 mm] vs. 8.5 mm [25th and 75th quartile, 7.6-9.1 mm], P < 0.0001) and maximal left ventricular wall thickness (4.5 mm [25th and 75th quartile, 4.1-4.7 mm] vs. 4.0 mm [25th and 75th quartile, 3.7-4.6 mm], P = 0.007) than those that did not. Multiple logistic regression analysis confirmed that both baseline variables were independent predictors for development of an HCM phenotype., Conclusions: The AMVL length was greater in cats that subsequently developed left ventricular hypertrophy. Further studies investigating the clinical application of AMVL in the natural history of feline HCM are warranted., (Copyright © 2021 Elsevier B.V. All rights reserved.)
- Published
- 2021
- Full Text
- View/download PDF
11. Balloon valvuloplasty of valvular pulmonary stenosis in a neonatal foal.
- Author
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Junge HK, Glaus T, Matos JN, Meira C, Schwarz A, Hoey S, Dennler M, Schwarzwald CC, and Mitchell KJ
- Subjects
- Angiography, Animals, Echocardiography veterinary, Female, Heart Ventricles, Horses, Treatment Outcome, Balloon Valvuloplasty veterinary, Horse Diseases, Pulmonary Valve Stenosis diagnostic imaging, Pulmonary Valve Stenosis therapy, Pulmonary Valve Stenosis veterinary
- Abstract
In a 1-day old filly with a loud heart murmur, transthoracic echocardiography revealed right ventricular hypertrophy associated with severe pulmonary valvular stenosis and a transvalvular pressure gradient (between right ventricle and pulmonary artery) of 125 mmHg. Computed tomographic angiography confirmed the finding, with no evidence of other relevant concurrent abnormalities. Balloon valvuloplasty was performed using a single balloon technique. The foal recovered well from anaesthesia. Following the procedure, the right ventricle-pulmonary artery transvalvular gradient decreased to 38 mmHg. At follow up examinations after 1 month, 1 year and 2 years, the filly showed normal exercise capacity and echocardiography confirmed the persistent substantial improvement in the transvalvular outflow gradient., Competing Interests: Conflict of Interest Statement The authors do not have any conflicts of interest to disclose., (Copyright © 2021 The Author(s). Published by Elsevier B.V. All rights reserved.)
- Published
- 2021
- Full Text
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12. The Use of 3D Printing Technology for Manufacturing Metal Antennas in the 5G/IoT Context.
- Author
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Helena D, Ramos A, Varum T, and Matos JN
- Abstract
With the rise of 5G, Internet of Things (IoT), and networks operating in the mmWave frequencies, a huge growth of connected sensors will be a reality, and high gain antennas will be desired to compensate for the propagation issues, and with low cost, characteristics inherent to metallic radiating structures. 3D printing technology is a possible solution in this way, as it can print an object with high precision at a reduced cost. This paper presents different methods to fabricate typical metal antennas using 3D printing technology. These techniques were applied as an example to pyramidal horn antennas designed for a central frequency of 28 GHz. Two techniques were used to metallize a structure that was printed with polylactic acid (PLA), one with copper tape and other with a conductive spray-paint. A third method consists of printing an antenna completely using a conductive filament. All prototypes combine good results with low production cost. The antenna printed with the conductive filament achieved a better gain than the other structures and showed a larger bandwidth. The analysis recognizes the vast potential of these 3D-printed structures for IoT applications, as an alternative to producing conventional commercial antennas.
- Published
- 2021
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13. Compact N-Band Tree-Shaped Multiplexer-Based Antenna Structures for 5G/IoT Mobile Devices.
- Author
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Ramos A, Varum T, and Matos JN
- Abstract
This paper presents a simple, compact and low-cost design method that allows one to obtain low-profile multi-band antennas for the overcrowded future generation networks, which are widely versatile and very heterogeneous in the K/Ka bands. The proposed antennas comprise n radiating monopoles, one for each of the desired operating frequencies, along with a frequency selective feeding network fed at a single point. This concept enables a single antenna to be shared with different radio-frequency (RF) frontends, potentially saving space. Typically, with n-band structures the biggest challenge is to make them highly efficient and here this is assured by multiplexing the frequency, and thus isolating each of the monopoles, allowing the design of scalable structures which fit the 5G applications. Based on the vision proposed here, a dual-band and a tri-band structures were built and characterized by their main parameters. Both prototypes achieved peak efficiencies around 80%, with adequate bandwidths and gains, as well as great compactness.
- Published
- 2020
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14. Reconfigurable Diplexer-Based Filtenna for Tx/Rx Operation in Mobile Satellite Terminals.
- Author
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Rodrigues L, Varum T, and Matos JN
- Abstract
Large constellations of low-orbit satellites have already been launched with the aim of offering complete worldwide coverage of broadband Internet; however, compact, simple, and low-cost mobile terminals are necessary to establish the communication. This paper describes the design of a reconfigurable and compact filtenna with the ability to switch between the satellites' uplink and downlink frequencies, 20 GHz and 29 GHz, maintaining an excellent performance. Due to its simplicity, efficiency, and Rx/Tx isolation, this antenna is a relevant candidate to be part of mobile terminals and devices, or even sensors, that communicate with satellites.
- Published
- 2020
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15. Investigation of optimal sample preparation conditions with potassium triiodide and optimal imaging settings for microfocus computed tomography of excised cat hearts.
- Author
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Simcock IC, Hutchinson JC, Shelmerdine SC, Matos JN, Sebire NJ, Fuentes VL, and Arthurs OJ
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- Animals, Cats, Iodides, Heart, Tomography, X-Ray Computed
- Abstract
Objective: To determine optimal sample preparation conditions with potassium triiodide (I
2 KI) and optimal imaging settings for microfocus CT (micro-CT) of excised cat hearts., Sample: 7 excised hearts (weight range, 10 to 17.6 g) obtained from healthy adult cats after euthanasia by IV injection of pentobarbital sodium., Procedures: Following excision, the hearts were preserved in 10% formaldehyde solution. Six hearts were immersed in 1.25% I2 KI solution (n = 3) or 2.5% I2 KI solution (3) for a 12-day period. Micro-CT images were acquired at time 0 (prior to iodination) then approximately every 24 and 48 hours thereafter to determine optimal sample preparation conditions (ie, immersion time and concentration of I2 KI solution). Identified optimal conditions were then used to prepare the seventh heart for imaging; changes in voltage, current, exposure time, and gain on image quality were evaluated to determine optimal settings (ie, maximal signal-to-noise and contrast-to-noise ratios). Images were obtained at a voxel resolution of 30 μm. A detailed morphological assessment of the main cardiac structures of the seventh heart was then performed., Results: Immersion in 2.5% I2 KI solution for 48 hours was optimal for sample preparation. The optimal imaging conditions included a tube voltage of 100 kV, current of 150 μA, and exposure time of 354 milliseconds; scan duration was 12 minutes., Conclusions and Clinical Relevance: Results provided an optimal micro-CT imaging protocol for excised cat hearts prepared with I2 KI solution that could serve as a basis for future studies of micro-CT for high resolution 3-D imaging of cat hearts.- Published
- 2020
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16. Case report - azygos vein drainage into the left atrium in a dog with cor triatriatum dexter and a patent foramen ovale.
- Author
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Dennler M, Matos JN, Gent TC, Knell S, Schertenleib TI, and Glaus TM
- Subjects
- Animals, Dog Diseases diagnostic imaging, Dog Diseases etiology, Dogs, Female, Foramen Ovale, Patent complications, Foramen Ovale, Patent diagnostic imaging, Foramen Ovale, Patent pathology, Azygos Vein pathology, Dog Diseases pathology, Foramen Ovale, Patent veterinary
- Abstract
A 2-year-old Airedale terrier was presented with exercise intolerance since birth and newly developed chylous pleural effusion. Imaging procedures including echocardiography, cardiac magnetic resonance imaging, computed tomography, and selective angiography revealed an aberrant connection of the azygos vein and the left atrium, a membrane in the right atrium consistent with cor triatriatum dexter, and a patent foramen ovale with right-to-left shunt. Balloon dilation of the membrane in the right atrium seemed to result in transient improvement of exercise tolerance compared with the previous 2 years. When chylothorax relapsed after three months, the dog was euthanized. Necropsy confirmed the azygos vein to left atrial connection, the patent foramen ovale, and the cor triatriatum dexter., (Copyright © 2019 Elsevier B.V. All rights reserved.)
- Published
- 2019
- Full Text
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17. Two-dimensional echocardiographic left- atrial-to-aortic ratio in healthy adult dogs: a reexamination of reference intervals.
- Author
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Rishniw M, Caivano D, Dickson D, Vatne L, Harris J, and Matos JN
- Subjects
- Animals, Dogs, Female, Humans, Male, Reference Values, Echocardiography veterinary, Heart anatomy & histology, Heart diagnostic imaging
- Abstract
Introduction: Left atrial-to-aortic ratios (LA:Ao) provide a body weight independent estimate of left atrial size. However, reference intervals were established with small sample populations and for only single points in the cardiac cycle. More robust reference intervals are warranted., Animals: Two hundred and thirty eight apparently healthy adult dogs., Materials and Methods: LA:Ao measurements were obtained at 3 points in the cardiac cycle - maximal dimension, at the closing of the aortic valve (or just before opening of the mitral valve) (LA:Ao
MAX ); minimal dimension, at the onset of the QRS complex (LA:AoMIN ) and at the onset of atrial systole (LA:AoP ). LA:AoMAX was obtained from right parasternal short and long-axis views, and LA:AoMIN and LA:AoP were obtained from the right parasternal short-axis view. Dogs were excluded from analyses of reference intervals if weight-based left atrial and left ventricular diastolic dimensions exceeded reference interval limits. Effects of breed and body weight on LA:Ao measurements were examined., Results: Upper LA:Ao reference limits mostly agreed with previously published limits, although 10% of dogs had LA:AoMAX in the short-axis view exceeding 1.6. These dogs had smaller aortae than expected for their body weight, and included mostly boxers and English setters. Reference limits for LA:AoMIN and LA:AoP were smaller than those for LA:AoMAX in either view. No LA:Ao measurements were associated with body weight., Conclusions: Reference limits were either confirmed or established for the common two-dimensional methods of assessing relative left atrial size in healthy dogs. Clinicians should use caution when diagnosing mild left atrial enlargement in certain dog breeds and should examine the weight-based aortic dimensions in such cases., (Copyright © 2019 Elsevier B.V. All rights reserved.)- Published
- 2019
- Full Text
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18. Compact Multilayer Yagi-Uda Based Antenna for IoT/5G Sensors.
- Author
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Ramos A, Varum T, and Matos JN
- Abstract
To increase the capacity and performance of communication systems, the new generation of mobile communications (5G) will use frequency bands in the mmWave region, where new challenges arise. These challenges can be partially overcome by using higher gain antennas, Multiple-Input Multiple-Output (MIMO), or beamforming techniques. Yagi-Uda antennas combine high gain with low cost and reduced size, and might result in compact and efficient antennas to be used in Internet of Thins (IoT) sensors. The design of a compact multilayer Yagi for IoT sensors is presented, operating at 24 GHz, and a comparative analysis with a planar printed version is shown. The stacked prototype reveals an improvement of the antenna's main properties, achieving 10.9 dBi, 2 dBi more than the planar structure. In addition, the multilayer antenna shows larger bandwidth than the planar; 6.9 GHz compared with 4.42 GHz. The analysis conducted acknowledges the huge potential of these stacked structures for IoT applications, as an alternative to planar implementations.
- Published
- 2018
- Full Text
- View/download PDF
19. Two-dimensional echocardiographic estimates of left atrial function in healthy dogs and dogs with myxomatous mitral valve disease.
- Author
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Dickson D, Caivano D, Matos JN, Summerfield N, and Rishniw M
- Subjects
- Animals, Atrial Fibrillation diagnostic imaging, Atrial Fibrillation physiopathology, Case-Control Studies, Dog Diseases physiopathology, Dogs physiology, Echocardiography veterinary, Female, Heart Atria diagnostic imaging, Heart Atria physiopathology, Heart Neoplasms diagnostic imaging, Heart Neoplasms physiopathology, Male, Mitral Valve Insufficiency diagnostic imaging, Mitral Valve Insufficiency physiopathology, Myxoma diagnostic imaging, Myxoma physiopathology, Reference Standards, Severity of Illness Index, Atrial Fibrillation veterinary, Atrial Function, Left, Dog Diseases diagnostic imaging, Heart Neoplasms veterinary, Mitral Valve Insufficiency veterinary, Myxoma veterinary
- Abstract
Objectives: To provide reference intervals for 2-dimensional linear and area-based estimates of left atrial (LA) function in healthy dogs and to evaluate the ability of estimates of LA function to differentiate dogs with subclinical myxomatous mitral valve disease (MMVD) and similarly affected dogs with congestive heart failure (CHF)., Animals: Fifty-two healthy adult dogs, 88 dogs with MMVD of varying severity., Methods: Linear and area measurements from 2-dimensional echocardiographs in both right parasternal long and short axis views optimized for the left atrium were used to derive estimates of LA active emptying fraction, passive emptying fraction, expansion index, and total fractional emptying. Differences for each estimate were compared between healthy and MMVD dogs (based on ACVIM classification), and between MMVD dogs with subclinical disease and CHF that had similar LA dimensions. Diagnostic utility at identifying CHF was examined for dogs with subclinical MMVD and CHF. Relationships with bodyweight were assessed., Results: All estimates of LA function decreased with increasing ACVIM stage of mitral valve disease (p<0.05) and showed negative relationships with increasing LA size (all r
2 values < 0.2), except for LA passive emptying fraction, which did not differ or correlate with LA size (p=0.4). However, no index of LA function identified CHF better than measurements of LA size. Total LA fractional emptying and expansion index showed modest negative correlations with bodyweight., Conclusions: Estimates of LA function worsen with worsening MMVD but fail to discriminate dogs with CHF from those with subclinical MMVD any better than simple estimates of LA size., (Copyright © 2017 Elsevier B.V. All rights reserved.)- Published
- 2017
- Full Text
- View/download PDF
20. Comparison of left and right ventricular stroke volume of dogs calculated on the basis of morphology and blood flow determined by use of cardiac magnetic resonance imaging.
- Author
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Dennler M, Richter H, Matos JN, Baron Toaldo M, Campagna IU, Glaus TM, and Kircher PR
- Subjects
- Animals, Aorta, Coronary Circulation, Dogs, Female, Heart Ventricles, Hemodynamics, Magnetic Resonance Angiography methods, Male, Magnetic Resonance Angiography veterinary, Stroke Volume, Ventricular Function
- Abstract
OBJECTIVE To compare stroke volume (SV) calculated on the basis of cardiac morphology determined by MRI and results of phase-contrast angiography (PCA) of ventricular inflow and outflow in dogs. ANIMALS 10 healthy Beagles. PROCEDURES Cardiac MRI was performed twice on each Beagle. Cine gradient echo sequences of both ventricles in short-axis planes were used for morphological quantification of SVs by assessment of myocardial contours. From the long-axis plane, SVs in 4-chamber and left ventricular 2-chamber views were acquired at end diastole and end systole. For calculation of SV on the basis of blood flow, PCA was performed for cardiac valves. RESULTS Mean ± SD values for SV quantified on the basis of blood flow were similar in all valves (aortic, 17.8 ± 4.1 mL; pulmonary, 17.2 ± 5.4 mL; mitral, 17.2 ± 3.9 mL; and tricuspid, 16.9 ± 5.1 mL). Morphological quantification of SV in the short-axis plane yielded significant differences between left (13.4 ± 2.7 mL) and right (8.6 ± 2.4 mL) sides. Morphological quantification of left ventricular SV in the long-axis plane (15.2 ± 3.3 mL and 20.7 ± 3.8 mL in the 4- and 2-chamber views) yielded variable results, which differed significantly from values for flow-based quantification, except for values for the morphological 4-chamber view and PCA for the atrioventricular valves, for which no significant differences were identified. CONCLUSIONS AND CLINICAL RELEVANCE In contrast to quantification based on blood flow, calculation on the basis of morphology for the short-axis plane significantly underestimated SV, probably because of through-plane motion and complex right ventricular anatomy.
- Published
- 2017
- Full Text
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21. Non-Uniform Microstrip Antenna Array for DSRC in Single-Lane Structures.
- Author
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Varum T, Matos JN, and Pinho P
- Abstract
Vehicular communications have been subject to a great development in recent years, with multiple applications, such as electronic payments, improving the convenience and comfort of drivers. Its communication network is supported by dedicated short range communications (DSRC), a system composed of onboard units (OBU) and roadside units (RSU). A recently conceived different set-up for the tolling infrastructures consists of placing them in highway access roads, allowing a number of benefits over common gateway infrastructures, divided into several lanes and using complex systems. This paper presents an antenna array whose characteristics are according to the DSRC standards. Additionally, the array holds an innovative radiation pattern adjusted to the new approach requirements, with an almost uniform wide beamwidth along the road width, negligible side lobes, and operating in a significant bandwidth., Competing Interests: The authors declare no conflict of interest.
- Published
- 2016
- Full Text
- View/download PDF
22. ECG of the Month. Isorhythmic atrioventricular dissociation during hypothermia.
- Author
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Pereira NJ, Glaus T, and Matos JN
- Subjects
- Animals, Cats, Heart Block diagnosis, Hypothermia complications, Hypothermia veterinary, Male, Cat Diseases diagnosis, Electrocardiography veterinary, Heart Block veterinary
- Published
- 2014
- Full Text
- View/download PDF
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