246 results on '"Tamás Varga"'
Search Results
52. Effect of interval training with non-invasive ventilation in severe chronic obstructive pulmonary disease—a prospective cohort study with matched control group
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Mónika Fekete, Péter Balázs, Maria Kerti, Stefano Tarantini, A. Németh, Zoltan Csizmadia, Vince Fazekas-Pongor, and János Tamás Varga
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Male ,BODE index ,medicine.medical_specialty ,medicine.medical_treatment ,Interval training ,Pulmonary Disease, Chronic Obstructive ,03 medical and health sciences ,0302 clinical medicine ,Internal medicine ,medicine ,Humans ,Pulmonary rehabilitation ,Prospective Studies ,030212 general & internal medicine ,Dynamic hyperinflation ,Prospective cohort study ,Advanced and Specialized Nursing ,COPD ,Noninvasive Ventilation ,business.industry ,medicine.disease ,Control Groups ,Dyspnea ,Anesthesiology and Pain Medicine ,Pulmonology ,030228 respiratory system ,Quality of Life ,Breathing ,Cardiology ,Female ,business - Abstract
BACKGROUND In severe chronic obstructive pulmonary disease (COPD), interval training (IT) can be performed with oxygen support, which provides beneficial effect on metabolic processes, tissue perfusion, and peripheral muscle function. METHODS A prospective cohort study with matched controls was performed on patients in Budapest at the Department of Pulmonary Rehabilitation of the National Koranyi Institute of Pulmonology between January 1, 2020 and March 1, 2020. After a complex condition assessment, both case and control patients participated in a 3-week long complex pulmonary rehabilitation (PR) program that included individual training, education, nutrition, and psychological counseling. Anthropometric and functional data of patients were recorded at both the beginning and end of the PR program. Our research aimed to assess the effect of non-invasive ventilation (NIV) in patients with severe COPD who underwent IT. RESULTS A total of 18 [male/female: 10 (55.6%)/8 (44.4%)] patients were enrolled in our study. IT with NIV significantly improved the patients' 6-minute walking distance (6MWD) (m) [216.0 (211.5-233.7) vs. 274.0 (247.5-313.5); P
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- 2021
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53. Freedive Training Gives Additional Physiological Effect Compared to Pulmonary Rehabilitation in COPD
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Zoltán Csizmadia, Pongrác Ács, Gergő József Szőllősi, Blanka Tóth, Mária Kerti, Antal Kovács, and János Tamás Varga
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Pulmonary Disease, Chronic Obstructive ,Dyspnea ,Health, Toxicology and Mutagenesis ,breath holding ,respiratory rate ,respiratory training ,respiratory effectiveness ,pulmonary rehabilitation ,Vital Capacity ,Public Health, Environmental and Occupational Health ,Quality of Life ,Humans ,Female - Abstract
Introduction: Pulmonary rehabilitation (PR) is beneficial for lung mechanics, chest kinematics, metabolism, and inspiratory and peripheral muscle function. Freediving training (FD) can be effective in sportsmen and can improve breath-holding time. Aims: We sought to determine the effectiveness of freediving training in the pulmonary rehabilitation of COPD patients. Patients and methods: Twenty-three COPD patients (15 men and 8 women; median age 63 years; FEV1: 41% pred; BMI: 28 kg/m2) participated in the FD + PR group (3 weeks PR and 3 weeks FD + PR) and 46 patients with COPD (25 men and 21 women; median age 66 years; FEV1: 43% pred; BMI: 27 kg/m2) participated in an inpatient PR program (6 weeks). Patients performed comfort zone breath holding for 30 min/day. Patients increased their breath-holding time within their comfort zone for 30 min. We detected lung function, chest expansion (CWE), inspiratory muscle pressure (MIP), peripheral muscle function (GS), and exercise capacity (6MWD), and we included breath-holding time (BHT), quality of life score (COPD Assessment Test (CAT)), modified Medical Research Dyspnea Scale (mMRC) score, and the severity of the disease assessed by the BODE index (FEV1, BMI, 6MWD, and mMRC) and an alternative scale (FEV1, BMI, 6MWD, and CAT). Result: There were significant differences in the characteristics of the two groups. Significant improvement was detected in all functional and quality of life parameters except lung function in both groups. Significantly higher improvement was detected in CWE, GS, 6MWD, BHT, CAT, mMRC, alternative scale, and MIP. The improvement in forced vital capacity (FVC) was not significant. There were no side effects of FD training. Conclusion: The FD method can potentiate the effect of PR, improving not only BHT but also other parameters. Trial registration: ISRCTN ISRCTN13019180. Registered 19 December 2017.
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- 2022
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54. Performance of the intracerebroventricularly injected streptozotocin Alzheimer's disease model in a translationally relevant, aged and experienced rat population
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Attila Gáspár, Barbara Hutka, Aliz Judit Ernyey, Brigitta Tekla Tajti, Bence Tamás Varga, Zoltán Sándor Zádori, and István Gyertyán
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Disease Models, Animal ,Multidisciplinary ,Alzheimer Disease ,Animals ,Rats, Long-Evans ,Rats, Wistar ,Streptozocin ,Rats - Abstract
The intracerebroventricularly (icv) injected streptozotocin (STZ) induced brain state is a widely used model of sporadic Alzheimer-disease (AD). However, data have been generated in young, naive albino rats. We postulate that the translationally most relevant animal population of an AD model should be that of aged rats with substantial learning history. The objective of the study was thus to probe the model in old rats with knowledge in various cognitive domains. Long-Evans rats of 23 and 10 months age with acquired knowledge in five-choice serial reaction time task (5-CSRTT), a cooperation task, Morris water-maze (MWM) and “pot-jumping” exercise were treated with 3 × 1.5 mg/kg icv. STZ and their performance were followed for 3 months in the above and additional behavioral assays. Both STZ-treated age groups showed significant impairment in the MWM (spatial learning) and novel object recognition test (recognition memory) but not in passive avoidance and fear conditioning paradigms (fear memory). In young STZ treated rats, significant differences were also found in the 5CSRTT (attention) and pot jumping test (procedural learning) while in old rats a significant increase in hippocampal phospho-tau/tau protein ratio was observed. No significant difference was found in the cooperation (social cognition) and pairwise discrimination (visual memory) assays and hippocampal β-amyloid levels. STZ treated old animals showed impulsivity-like behavior in several tests. Our results partly coincide with partly deviate from those published on young, albino, unexperienced rats. Beside the age, strain and experience level of the animals differences can also be attributed to the increased dose of STZ, and the applied food restriction regime. The observed cognitive and non-cognitive activity pattern of icv. STZ in aged experienced rats call for more extensive studies with the STZ model to further strengthen and specify its translational validity.
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- 2022
55. What do we know already about reactor runaway? – A review
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Tamás Varga and Alex Kummer
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021110 strategic, defence & security studies ,Environmental Engineering ,Warning system ,Thermal runaway ,Computer science ,Research areas ,General Chemical Engineering ,Nuclear engineering ,0211 other engineering and technologies ,Thermal safety ,02 engineering and technology ,010501 environmental sciences ,Reactor design ,01 natural sciences ,Assessment methods ,Environmental Chemistry ,Safety, Risk, Reliability and Quality ,Reactor safety ,0105 earth and related environmental sciences - Abstract
Nowadays, reactor runaway is still a crucial phenomen from the safety viewpoint. About 120 scientific journal articles are published every year in the last decade in which thermal runaway is a keyword. The possible cause and consequences of reactor runaway are adressed where the worst case is the explosion of the reactor. Prevention steps to avoid the development of thermal runaway include the appropriate design of the reactor, the operation strategy and an early warning detection system. The available assessment methods for thermal risk analysis are addressed in detail. Reactor runaway criteria can indicate early the thermal runaway, which criteria are addressed in this review in detail under three classes: geometry-, sensitivity-, and stability-based runaway criteria. Operation strategy of semi-batch reactors can be designed by calculating Westerterp-diagram whose evolution is cleary presented. Significant works on the field of the reactor design, operation and reactor safety are collected and evaluated. Finally possible further research areas are suggested to improve our knowledge about thermal safety, such as investigating parameter uncertainty in runaway indication or optimize the safety actions to moderate the consequences of runaway.
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- 2021
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56. Acute heart transplantation from mechanical circulatory support in a human immunodeficiency virus‐positive patient with fulminant myocarditis
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István Hartyánszky, Béla Merkely, Kristóf Rácz, Balázs Sax, Endre Németh, János Szlávik, Zoltán Prohászka, Viktor Berzsenyi, Attila Fintha, Ákos Király, Tamás Varga, Zsófia Szakál-Tóth, Gergely Csikos, Adam Soltesz, and Katalin Monostory
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lcsh:Diseases of the circulatory (Cardiovascular) system ,medicine.medical_specialty ,Myocarditis ,medicine.medical_treatment ,Fulminant ,Case Report ,Case Reports ,Heart transplantation ,030204 cardiovascular system & hematology ,03 medical and health sciences ,0302 clinical medicine ,Mechanical circulatory support ,Internal medicine ,medicine ,Extracorporeal membrane oxygenation ,030212 general & internal medicine ,Human immunodeficiency virus ,business.industry ,Cardiogenic shock ,Acute heart failure ,medicine.disease ,Transplantation ,Secondary thrombotic microangiopathy ,lcsh:RC666-701 ,Heart failure ,Acute myocarditis ,Circulatory system ,Cardiology ,Cardiology and Cardiovascular Medicine ,business - Abstract
Since the establishment of highly active antiretroviral therapy, survival rates have improved among patients with human immunodeficiency virus infection giving them the possibility to become transplant candidates. Recent publications revealed that human immunodeficiency virus‐positive heart transplant recipients' survival is similar to non‐infected patients. We present the case of a 40‐year‐old human immunodeficiency virus infected patient, who was hospitalized due to severely decreased left ventricular function with a possible aetiology of acute myocarditis, that has later been confirmed by histological investigation of myocardial biopsy. Due to rapid progression to refractory cardiogenic shock, extracorporeal membrane oxygenation implantation had been initiated, which was upgraded to biventricular assist device later. On the 35th day of upgraded support, the patient underwent heart transplantation uneventfully. Our clinical experience confirms that implementation of temporary mechanical circulatory support and subsequent cardiac transplantation might be successful in human immunodeficiency virus‐positive patients even in case of new onset, irreversible acute heart failure.
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- 2021
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57. Decision tree and first-principles model-based approach for reactor runaway analysis and forecasting.
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Tamás Varga, Ferenc Szeifert, and János Abonyi
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- 2009
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58. CAN THE 14C PRODUCTION IN 1055 CE BE AFFECTED BY SN1054?
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Fabio Marzaioli, Markku Oinonen, Irina P. Panyushkina, G. Porzio, Filippo Terrasi, Isabella Passariello, Chris Baisan, A. J. T. Jull, Manuela Capano, Ilya Usoskin, G. A. Kovaltsov, Tamás Varga, Pekka Nöjd, Raffaele Buompane, Stepan Poluianov, Mihály Molnár, J Uusitalo, Samuli Helama, Terrasi, F, Marzaioli, F, Buompane, R, Passariello, I, Porzio, G, Capano, M, Helama, S, Oinonen, M, Nöjd, P, Uusitalo, J, T Jull, A J, P Panyushkina, I, Baisan, C, Molnar, M, Varga, T, Kovaltsov, G, Poluianov, S, Usoskin, I, University of the Study of Campania Luigi Vanvitelli, INNOVA SCaRL, Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Natural Resources Institute Finland (LUKE), Finnish Museum of Natural History (LUOMUS), Helsingin yliopisto = Helsingfors universitet = University of Helsinki, University of Arizona, Institute for Nuclear Research [Budapest] (ATOMKI), Hungarian Academy of Sciences (MTA), Laboratory of Tree-Ring Research, A.F. Ioffe Physical-Technical Institute, Russian Academy of Sciences [Moscow] (RAS), University of Oulu, and University of Helsinki
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Solar minimum ,010506 paleontology ,Archeology ,biology ,Solar flare ,Sequoia ,[SDU.STU]Sciences of the Universe [physics]/Earth Sciences ,Magnitude (mathematics) ,Atmospheric sciences ,biology.organism_classification ,01 natural sciences ,law.invention ,Supernova ,13. Climate action ,law ,0103 physical sciences ,General Earth and Planetary Sciences ,Environmental science ,Radiocarbon dating ,010303 astronomy & astrophysics ,Event (particle physics) ,ComputingMilieux_MISCELLANEOUS ,0105 earth and related environmental sciences - Abstract
Annually resolved radiocarbon (14C) measurements on tree rings led to the discovery of abrupt variations in 14C production attributed to large solar flares. We present new results of annual and subannual 14C fluctuations in tree rings from a middle-latitude sequoia (California) and a high-latitude pine (Finland), analyzed for the period 1030–1080 CE, to trace a possible impact of the Crab supernova explosion, occurring during the Oort minimum of solar activity. Our results indicate an increase of Δ14C around 1054/55 CE, which we estimate is higher in magnitude than the cyclic variability due to solar activity at a 2σ significance level. The net signal appears to be synchronized in the studied locations. Several sources of this event are possible including γ-rays from the Crab supernova, an unusually weak solar minimum or a solar energetic particle incident. More data are needed to provide more insight into the origin of this 14C event.
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- 2020
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59. Right ventricular mechanical pattern in patients undergoing mitral valve surgery: a predictor of post‐operative dysfunction?
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Béla Merkely, Zoltán Tősér, Kristóf Rácz, Szabolcs Szigeti, Bálint Károly Lakatos, Erika Kispál, Tamás Varga, Attila Kovács, Márton Tokodi, Adam Soltesz, Levente Staub, János Gál, and Endre Németh
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Male ,medicine.medical_specialty ,lcsh:Diseases of the circulatory (Cardiovascular) system ,medicine.medical_treatment ,Heart Ventricles ,Mitral valve surgery ,030204 cardiovascular system & hematology ,law.invention ,Contractility ,03 medical and health sciences ,0302 clinical medicine ,law ,Internal medicine ,medicine.artery ,Original Research Articles ,Medicine ,Humans ,030212 general & internal medicine ,Original Research Article ,Cardiac Surgical Procedures ,Right ventricular dysfunction ,Ejection fraction ,3D echocardiography ,business.industry ,Mitral valve replacement ,Mitral Valve Insufficiency ,medicine.disease ,Intensive care unit ,medicine.anatomical_structure ,Ventricle ,lcsh:RC666-701 ,Heart failure ,Pulmonary artery ,Cardiology ,Ventricular Function, Right ,Mitral Valve ,Right ventricle ,Female ,Cardiology and Cardiovascular Medicine ,business ,Mitral valve regurgitation - Abstract
Aims The PREPARE‐MVR study (PRediction of Early PostoperAtive Right vEntricular failure in Mitral Valve Replacement/Repair patients) sought to investigate the alterations of right ventricular (RV) contraction pattern in patients undergoing mitral valve replacement/repair (MVR) and to explore the associations between pre‐operative RV mechanics and early post‐operative RV dysfunction (RVD). Methods and results We prospectively enrolled 42 patients (63 ± 11 years, 69% men) undergoing open‐heart MVR. Transthoracic three‐dimensional (3D) echocardiography was performed pre‐operatively, at intensive care unit discharge, and 6 months after surgery. The 3D model of the RV was reconstructed, and RV ejection fraction (RVEF) was calculated. We decomposed the motion of the ventricle to compute longitudinal ejection fraction (LEF) and radial ejection fraction (REF). Pulmonary artery catheterization was performed to monitor RV stroke work index (RVSWi). RVEF was slightly decreased after MVR [52 (50–55) vs. 51 (46–54)%; P = 0.001], whereas RV contraction pattern changed notably. Before MVR, the longitudinal shortening was the main contributor to global systolic RV function [LEF/RVEF vs. REF/RVEF; 0.53 (0.47–0.58) vs. 0.33 (0.22–0.42); P
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- 2020
60. Improved understanding of reaction kinetic identification problems using different nonlinear optimization algorithms
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Tibor Chován, Tamás Varga, and Zoltán Till
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Computer science ,General Chemical Engineering ,02 engineering and technology ,General Chemistry ,Variance (accounting) ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Kinetic energy ,01 natural sciences ,0104 chemical sciences ,Nonlinear programming ,Parameter identification problem ,Identification (information) ,Key (cryptography) ,Sensitivity (control systems) ,0210 nano-technology ,MATLAB ,Algorithm ,computer ,computer.programming_language - Abstract
The correct answer regarding which nonlinear optimization algorithm should we use for a given problem is that “it depends.” In this paper, we would like to add that “it depends, but use multiple programs whenever possible.” Here we consider 23 algorithms, implemented in MATLAB, evaluating their performance both on a lumped kinetic model for vacuum gas oil hydrocracking and a few-step kinetic model for ethane pyrolysis; the former particularly raised our interest as the kinetic parameters have no reference values in such models. We can use the results of such a study to estimate model variance; moreover, the statistical analysis of the identified minimum values can also quantify the parameter uncertainty. We can also identify key operating conditions where the applied kinetic model shows the highest sensitivity to the identified parameters, opening up the possibility to further reduce the uncertainty by targeting additional experimental work or by refining the identification problem.
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- 2020
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61. Uncertainties of Lumped Reaction Networks in Reactor Design
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Tibor Chován, Tamás Varga, and Zoltán Till
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Materials science ,ComputingMethodologies_SIMULATIONANDMODELING ,General Chemical Engineering ,Nuclear engineering ,General Chemistry ,Reactor design ,Industrial and Manufacturing Engineering - Abstract
The so-called lumped reaction networks are extensively used to model complex processes such as hydrocracking. Despite this, studies on the further applicability of these networks during a reactor s...
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- 2020
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62. Drought tolerance in maize is influenced by timing of drought stress initiation
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Tamás Varga, Gary W. Feyereisen, Jeffrey A. Coulter, Samadangla Ao, and Michael P. Russelle
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Drought stress ,Agronomy ,Drought tolerance ,Biology ,Agronomy and Crop Science - Published
- 2020
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63. The inhibitor preincubation effect is universal to SLC transporter assays and is only partially eliminated in the presence of extracellular protein
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Peter Tatrai, Csilla Temesszentandrási-Ambrus, Tamás Varga, and Zsuzsanna Gáborik
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Pharmacology ,Pharmaceutical Science - Published
- 2023
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64. Novel distributed parameter model-based continuous lumping approach: An application to a pilot-plant hydrocracking reactor
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Omár Péter Hamadi and Tamás Varga
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Applied Mathematics ,General Chemical Engineering ,General Chemistry ,Industrial and Manufacturing Engineering - Published
- 2023
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65. Radiocarbon dating of microliter sized Hungarian Tokaj wine samples
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Tamás Varga, Mihály Molnár, Anita Molnár, A.J. Timothy Jull, László Palcsu, and Elemér László
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Food Science - Published
- 2023
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66. Posttraumatic Contour Deformities Reconstruction and Scar Treatment with Microstructural and Nanofat Grafting in the Face
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Gergely Pataki, Tamás Varga, Artúr Kalatovics, and Sarolta Magyar
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- 2022
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67. The potential of radiocarbon analysis for the detection of art forgeries
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Irka Hajdas, Lucio Calcagnile, Mihaly Molnár, Tamás Varga, Gianluca Quarta, Hajdas, I., Calcagnile, L., Molnar, M., Varga, T., and Quarta, G.
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AMS, Art forgeries, Bomb peak, Cultural heritage, Radiocarbon ,Bomb peak ,Art forgeries ,Radiometric Dating ,Cultural heritage ,AMS ,Radiocarbon ,Carbon Radioisotopes ,Law ,Art ,Mass Spectrometry ,Pathology and Forensic Medicine - Abstract
Art objects form an essential part of cultural heritage and are appreciated for their artistic values. However, the observed investment in art and capacity for high monetary returns encourages counterfeiting of art objects. The art market's lack of transparency and traditional confidential protocols amplifies the problem. Radiocarbon analysis provides a tool to detect anachronistic materials. Measurement of bomb peak radiocarbon, which was observed in the atmosphere during the last 70 years, can provide clear evidence of post-1950 material. Here we briefly introduce the method and discuss its application in detecting forgeries. Three accelerator mass spectrometry AMS laboratories performed a 14C dating inter-comparison study on the material used in art. Results obtained on modern cotton paper, two antique sheets of paper, one parchment, and one textile demonstrate the radiocarbon dating capacity to date the material accurately. The excellent agreement between laboratories is crucial for the broader application of this scientific tool in forensic studies and court cases., Forensic Science International, 335, ISSN:0379-0738, ISSN:1872-6283
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- 2022
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68. Offline Handwriting Recognition Using Synthetic Training Data Produced By Means Of A Geometrical Distortion Model.
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Tamás Varga and Horst Bunke
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- 2004
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69. Köldökig érő miómásan elfajult uterus robotasszisztált eltávolítása.
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Bálint, Farkas, Tamás, Varga, Péter, Vida, Nikoletta, Bárdos, József, Bódis, and Kálmán, Kovács
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Copyright of Magyar Nőorvosok Lapja is the property of Hungarian Society of Obsterics & Gynaecology 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.)
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- 2023
70. Mesterséges neurális hálózatok az állatitermék-előállításban.
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Ágnes, Nagy Sára, István, Csabai, Tamás, Varga, Bettina, Póth-Szebenyi, György, Gábor, and Norbert, Solymosi
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ARTIFICIAL neural networks ,ARTIFICIAL intelligence ,AGRICULTURE ,MACHINE learning ,SWINE farms - Abstract
Copyright of Magyar Állatorvosok Lapja is the property of Herman Otto Intezet Nonprofit Kft. 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.)
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- 2023
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71. Introduction of a pharmacological neurovascular uncoupling model in rats based on results of mice
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Bence Tamás Varga, Attila Gáspár, Aliz Judit Ernyey, Barbara Hutka, Brigitta Tekla Tajti, Zoltán Sándor Zádori, and István Gyertyán
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Physiology (medical) - Abstract
Our aim was to establish a pharmacologically induced neurovascular uncoupling (NVU) method in rats as a model of human cognitive decline. Pharmacologically induced NVU with subsequent neurological and cognitive defects was described in mice, but not in rats so far. We used 32 male Hannover Wistar rats. NVU was induced by intraperitoneal administration of a pharmacological “cocktail” consisting of N-(methylsulfonyl)-2-(2-propynyloxy)-benzenehexanamide (MSPPOH, a specific inhibitor of epoxyeicosatrienoic acid-producing epoxidases, 5 mg kg−1), L-NG-nitroarginine methyl ester (L-NAME, a nitric oxide synthase inhibitor, 10 mg kg−1) and indomethacin (a nonselective inhibitor of cyclooxygenases, 1 mg kg−1) and injected twice daily for 8 consecutive days. Cognitive performance was tested in the Morris water-maze and fear-conditioning assays. We also monitored blood pressure. In a terminal operation a laser Doppler probe was used to detect changes in blood-flow (CBF) in the barrel cortex while the contralateral whisker pad was stimulated. Brain and small intestine tissue samples were collected post mortem and examined for prostaglandin E2 (PGE2) level. Animals treated with the “cocktail” showed no impairment in their performance in any of the cognitive tasks. They had higher blood pressure and showed cca. 50% decrease in CBF. Intestinal bleeding and ulcers were found in some animals with significantly decreased levels of PGE2 in the brain and small intestine. Although we could evoke NVU by the applied mixture of pharmacons, it also induced adverse side effects such as hypertension and intestinal malformations while the treatment did not cause cognitive impairment. Thus, further refinements are still required for the development of an applicable model.
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- 2021
72. Synthesis of iron oxide nanoparticles for DNA purification
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Tamás Varga, Ágnes Maria Ilosvai, Béla Viskolcz, Béla Fiser, Zoltán Kónya, Csaba Váradi, Ferenc Kristály, Ádám Prekob, László Vanyorek, and Emma Szőri-Dorogházi
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Polymers and Plastics ,Iron oxide ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Combustion ,DNA extraction ,Surfaces, Coatings and Films ,Sonochemistry ,chemistry.chemical_compound ,020401 chemical engineering ,chemistry ,Ferrocene ,PEG ratio ,0204 chemical engineering ,Physical and Theoretical Chemistry ,0210 nano-technology ,Iron oxide nanoparticles ,Superparamagnetism ,Nuclear chemistry - Abstract
Sonochemistry in combination with a combustion procedure was used to prepare superparamagnetic iron oxide nanoparticles. Two different iron precursors, ferrocene and iron(II)-acetate were dispersed...
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- 2019
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73. The ESS for evolutionary matrix games under time constraints and its relationship with the asymptotically stable rest point of the replicator dynamics
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József Garay, Tamás Varga, and Tamás F. Móri
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Time Factors ,Property (philosophy) ,Population Dynamics ,Dimension (graph theory) ,Population ,Stability (learning theory) ,01 natural sciences ,replicator dynamics ,010305 fluids & plasmas ,evolutionary stability ,matrix game ,03 medical and health sciences ,monomorphic ,Game Theory ,Stability theory ,time constraint ,0103 physical sciences ,Replicator equation ,Quantitative Biology::Populations and Evolution ,Applied mathematics ,education ,030304 developmental biology ,Mathematics ,0303 health sciences ,education.field_of_study ,Applied Mathematics ,Neighbourhood (graph theory) ,State (functional analysis) ,Biological Evolution ,Agricultural and Biological Sciences (miscellaneous) ,Phenotype ,Modeling and Simulation ,polymorphic ,population game - Abstract
Recently we interpreted the notion of ESS for matrix games under time constraints and investigated the corresponding state in the polymorphic situation. Now we give two further static (monomorphic) characterizations which are the appropriate analogues of those known for classical evolutionary matrix games. Namely, it is verified that an ESS can be described as a neighbourhood invader strategy independently of the dimension of the strategy space in our non-linear situation too, that is, a strategy is an ESS if and only if it is able to invade and completely replace any monomorphic population which totally consists of individuals following a strategy close to the ESS. With the neighbourhood invader property at hand, we establish a dynamic characterization under the replicator dynamics in two dimensions which corresponds to the strong stability concept for classical evolutionary matrix games. Besides, in some special cases, we also prove the stability of the corresponding rest point in higher dimensions.
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- 2019
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74. Spatial Distribution of 14C in Tree Leaves from Bali, Indonesia
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Zsuzsa Lisztes-Szabó, Tamás Varga, Mihály Molnár, and A. J. Timothy Jull
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Archeology ,chemistry.chemical_element ,Vegetation ,Evergreen ,Photosynthesis ,Spatial distribution ,Atmospheric sciences ,law.invention ,Atmosphere ,chemistry ,law ,General Earth and Planetary Sciences ,Environmental science ,Radiocarbon dating ,Carbon ,Woody plant - Abstract
The increase of fossil-fuel-derived CO2 in the atmosphere has led to the dilution of the atmospheric radiocarbon concentration, but due to the costly instrumentation, the continuous atmospheric 14C/12C data is incomplete in developing countries, such as in Indonesia. These data give useful information about the level of local and regional fossil emissions. In this study, 14C AMS measurements of local vegetation and woody plant species samples have been used to estimate the rate of fossil-fuel-derived carbon in the plants, which fix the CO2 from the atmosphere by photosynthesis. Evergreen leaf samples were collected in September 2018 on the island of Bali in different, diverse districts in local and urban areas. The samples from the densely populated areas show observable fossil fuel emissions and show that the Δ14C level is close to zero ‰, similar to the natural level.
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- 2019
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75. Fossil Carbon Load in Urban Vegetation for Debrecen, Hungary
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Tamás Varga, István Major, Petra Barnucz, Elemér László, Mihály Molnár, A. J. Timothy Jull, Zsuzsa Lisztes-Szabó, and János Pénzes
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010506 paleontology ,Archeology ,010504 meteorology & atmospheric sciences ,Urban vegetation ,chemistry.chemical_element ,Sampling (statistics) ,Forestry ,Vegetation ,01 natural sciences ,Fossil carbon ,law.invention ,Deciduous ,chemistry ,law ,Urban background ,General Earth and Planetary Sciences ,Environmental science ,Radiocarbon dating ,Carbon ,0105 earth and related environmental sciences - Abstract
Deciduous tree leaf and grass samples were collected in Debrecen, the second largest city in Hungary. The aim of the study was to determine the rate of fossil fuel-derived carbon in urban vegetation. At the locations sampled, C3 and C4 plants close to roads were collected in September 2017. In total, 82 tree and grass leaf samples were gathered at 36 different sampling points all over the city of Debrecen. The radiocarbon (14C) results of the samples were compared to the local urban background atmospheric 14CO2 data to determine the percentage of the fossil fuel-derived carbon in the plants. Based on our results, the average fossil carbon content in the tree and grass leaf samples were 0.9 ± 1.2% and 2.5 ± 2.5%, respectively. The highest fossil carbon content was 9.6 ± 0.6% in a grass and 4.7 ± 0.7% in a tree leaf sample. It appears that the negative fossil carbon content results obtained at urban sampling areas reflect modern carbon emission, where radiocarbon content is higher than the corresponding local background, presumably due burning of recent wood containing bomb 14C in the suburbs as well as other possible sources such as litter decomposition or soil CO2 emission.
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- 2019
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76. Noble-metal-free and Pt nanoparticles-loaded, mesoporous oxides as efficient catalysts for CO2 hydrogenation and dry reforming with methane
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Anett Gyuris, András Sápi, Tamás Varga, András Grósz, Ákos Kukovecz, Kornélia B. Ábrahámné, Anastasiia Efremova, Zoltán Kónya, János Kiss, T. Rajkumar, Imre Szenti, and Marietta Ábel
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Materials science ,Carbon dioxide reforming ,Process Chemistry and Technology ,Non-blocking I/O ,engineering.material ,Methane ,Catalysis ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,engineering ,Chemical Engineering (miscellaneous) ,Noble metal ,Selectivity ,Mesoporous material ,Waste Management and Disposal ,Template method pattern - Abstract
In this study, a series of free-standing as well as controlled size Pt nanoparticles-loaded mesoporous metal oxides (NiO, Co3O4, CeO2 and MnO2) with high surface area and designed pore structure were prepared by hard template method and used as catalysts for CO2 hydrogenation together with dry reforming of CO2 with methane. The physicochemical properties of catalysts were analysed by N2 adsorption-desorption isotherm, XRD, TEM, and H2-TPR. Pt-free and Pt-loaded mesoporous NiO and Co3O4 performed with high catalytic activity and selectivity for both CO2 activation reactions. Pt-free NiO exhibited the highest catalytic activity and also showing 100% CH4 selectivity between 473–673 K and ˜1:1 H2/CO2 ratio between 673–973 K in CO2 hydrogenation and dry reforming with methane, respectively. The enhanced catalytic properties can be due to the existence of metallic Ni as well as the optimal dynamics of Ni/NiOx structure under reaction conditions.
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- 2019
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77. Variation of 14C in Japanese Tree Rings Related to the Fukushima Nuclear Accident
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A. J. Timothy Jull, Tamás Varga, László Palcsu, Tomoko Ohta, Mihály Molnár, and Yasunori Mahara
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010506 paleontology ,Archeology ,010504 meteorology & atmospheric sciences ,biology ,Fukushima Nuclear Accident ,Cryptomeria ,Growing season ,biology.organism_classification ,01 natural sciences ,Pacific ocean ,law.invention ,Suess effect ,law ,Dendrochronology ,General Earth and Planetary Sciences ,Environmental science ,Physical geography ,Radiocarbon dating ,Air mass ,0105 earth and related environmental sciences - Abstract
Radiocarbon (14C) analysis was performed on Japanese cedar (Cryptomeria japonica) tree rings from Koriyama, Fukushima prefecture. Our primary aim was to detect any 14C release from the Fukushima Dai-ichi nuclear power plant accident on 11 March 2011. We also completed and assessed the 14C level in Japanese tree rings for the period of 1990–2014 because of the lack of environmental 14C results in the Japanese island that time. For this reason, we used a trajectory model to investigate the air mass forward and backward trajectories at the area of the power plant and sampling site. The modeling data show that the air masses mainly moved to the Pacific Ocean, both during March 2011 and during the growing season (March–September). During the period 1990–2014 there was no significant 14C excess in any of the samples, but there was a detectable Suess effect in almost every tree ring sample. The average fossil contribution was 0.83 ± 0.01% and the calculated anthropogenic component ratio, the 14C excess varied between +0.5 and –1.6%. The Δ14C value decreased from 150.0‰ to 9.5‰ from 1990–2014, which follows the decline of the 14C bomb peak, in addition to any detectable Suess effect.
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- 2019
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78. Identification of Potential Methane Source Regions in Europe Using δ 13 C CH4 Measurements and Trajectory Modeling
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Rebecca Fisher, A. J. T. Jull, E. László, Tamás Varga, István Major, László Haszpra, Mihály Molnár, David Lowry, and Euan G. Nisbet
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Atmospheric Science ,chemistry.chemical_compound ,Identification (information) ,Geophysics ,chemistry ,Space and Planetary Science ,Greenhouse gas ,Earth and Planetary Sciences (miscellaneous) ,Cross correlation analysis ,Trajectory ,Environmental science ,Methane ,Remote sensing - Abstract
The methane emissions from the Hungarian Pannonian Basin are not well qualified, due to a lack of measurements of CH4 mole fraction and δ13CCH4 in the air. This study reports methane measurements in air samples from Hungary, placing them in the context of regional and global background data, to investigate the inputs to the methane burden in Central Europe. CH4 mole fraction and δ13CCH4 from the Hungarian tall tower station, Hegyhátsál, and additional data from Mace Head (Ireland) and Zeppelin (Svalbard) are used with back-trajectory modeling to identify central European source areas and their seasonal variation between the summer vegetation and winter heating periods. Methane measurements in air masses sampled in the European interior, have significantly higher maxima and seasonal amplitudes than at the Mace Head and Zeppelin European background sites. The mean CH4 mole fraction value is about 80 ppb higher than the comparable marine background, and values above 2000 ppb were frequently observed between February 2013 and December 2015. The mean δ13CCH4 value -47.5±0.3 ‰ (2σ) was comparable to values at all three monitoring sites, but specific pollution events were detected at Hegyhátsál. Concentration weighted trajectory modeling, meteorological parameters, stable carbon isotopic composition (δ13CCH4), and Miller-Tans analysis show that the main factors influencing CH4 at the Hegyhátsál, apart from diurnal and seasonal changes in the Planetary Boundary Layer, are emissions from residential heating and industrial CH4 emissions during the winter.
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- 2021
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79. Does Health Literacy Reinforce Disease Knowledge Gain? A Prospective Observational Study of Hungarian COPD Patients
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Márta Csabai, Orsolya Papp-Zipernovszky, Peter J. Schulz, and János Tamás Varga
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medicine.medical_specialty ,self-management ,Self-management ,business.industry ,media_common.quotation_subject ,Context (language use) ,Health literacy ,lifestyles ,General Medicine ,Disease ,Literacy ,Article ,Correlation ,Internal medicine ,Medicine ,Psychological testing ,Observational study ,business ,health literacy ,media_common ,health services utilization - Abstract
We set out to measure the health literacy (HL) of COPD patients using the Short Test of Functional Health Literacy (S-TOFHLA), perception-based screening questions (BHLS), and a specific disease knowledge test (COPD-Q). Our main focus is the relationship between functional HL and patients’ disease-knowledge, which contributes to the clarification of the relationship between the different kinds of HL. In two prospective observational studies, 151 COPD patients (80 males, mean age: 62 ± 9 years) completed a questionnaire containing HL measurements, psychological tests (e.g., the Self-Control and Self-Management Scale), and questions regarding subjective health status. Medical data of the patients from the MedSole system were added. The HL scores of the COPD patients were compared to a representative sample using a t-test. Furthermore, correlations of HL with demographic, psychological, and medical variables were calculated within the patient group. The relations among the different HL measurements were tested by chi-square trials. COPD patients had significantly lower HL, as measured by S-TOFHLA. Younger and higher educated patients possessed higher S-TOFHLA scores. Unlike the demographic variables, general self-management showed significant correlations with both BHLS and with COPD-Q. Out of the medical variables, objective health status was associated with BHLS and COPD-Q. Neither BHLS nor S-TOFHLA had a correlation with COPD-Q, but they correlated with each other. We found S-TOFHLA to be a better tool in the medical context. There is a clear gap between self-perceived/functional HL and the necessary disease knowledge. Rehabilitation care for patients with lower HL was more advantageous.
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- 2021
80. Rape, sunflower and forest honeys for long-term environmental monitoring: Presence of indicator elements and non-photosynthetic carbon in old Hungarian samples
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Máté Csontos, Tamás Varga, Mihály Molnár, Zita Gajdos, A. J. Timothy Jull, Edina Baranyai, Zsuzsa Lisztes-Szabó, Petra Burik, and Zsófi Sajtos
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Environmental Engineering ,Environmental reconstruction ,Acacia ,chemistry.chemical_element ,Forests ,Photosynthesis ,law.invention ,law ,Environmental monitoring ,Environmental Chemistry ,Animals ,Radiocarbon dating ,Waste Management and Disposal ,Elemental composition ,Hungary ,biology ,Honey ,Bees ,biology.organism_classification ,Pollution ,Sunflower ,Carbon ,Agronomy ,chemistry ,Rape ,Environmental science ,Helianthus ,Environmental Monitoring - Abstract
In this paper, we present the time-dependent elemental composition and AMS radiocarbon dating results of 36 rape, sunflower and forest honey samples, collected between 1985 and 2018 in geographically close locations. Based on the elemental information, we conclude that bee products regardless the type provide useful environmental information of the previous decades, such as the decreasing trend of airborne Pb emission can be traced. However, radiocarbon results agree less with the atmospheric bomb peak. Random offsets were observed in the specific radiocarbon activity of the honey samples indicating that rape, sunflower and forest honey samples are not as reliable materials for radiocarbon dating as acacia honeys. The radiocarbon results show that the rape, sunflower and forest honey samples can contain non-photosynthetic carbon, presumably derived from the soil. Thus, the complex application of honey samples for environmental reconstruction requires the species-separated investigation of bee products to reveal their adaptability for assessment approaches.
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- 2021
81. Monomorphic ESS does not imply the stability of the corresponding polymorphic state in the replicator dynamics in matrix games under time constraints
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József Garay and Tamás Varga
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Replicator equation ,State (functional analysis) ,Statistical physics ,Stability (probability) ,Matrix games ,Mathematics - Abstract
One of the main result in the theory of classical evolutionary matrix games (Maynard Smith and Price 1973, Maynard Smith 1982) claims that monomorphic ESS condition implies the stability of the corresponding state of the polymorphic replicator dynamics (Hofbauer et al. 1979, Zeeman 1980). The picture was then refined by Cressman (1990) introducing the strong stability concept which says that if there is a monomorphic ESS then stable polymorphism is established in polymorphic populations. In this paper we demonstrate with examples that this relationship generally does not hold in three or higher dimensions if times related to the interactions vary with the strategies of the participants.
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- 2021
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82. Exercise as a multi-modal disease-modifying medicine in systemic sclerosis: An introduction by The Global Fellowship on Rehabilitation and Exercise in Systemic Sclerosis (G-FoRSS)
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Anne-Marie Russell, Kim Fligelstone, Malin Regardt, Henrik Pettersson, Kelly Jensen, János Tamás Varga, Janet L. Poole, Carol Feghali-Bostwick, Elizabeth R. Volkmann, Yasser Salam, Mary Beth Scholand, Lee Shapiro, Matthew R. Lammi, Nancy Baldwin, Jennifer Mansour, Cecília Varjú, Monica Holmner, Matty Heenan, Tracy Frech, Helene Alexanderson, and Lesley Ann Saketkoo
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Autoimmune disease ,medicine.medical_specialty ,Rehabilitation ,Scleroderma, Systemic ,business.industry ,medicine.medical_treatment ,Interstitial lung disease ,Disease ,medicine.disease ,Fibrosis ,Scleroderma ,Article ,Rheumatology ,Myokine ,Activities of Daily Living ,medicine ,Humans ,Pulmonary rehabilitation ,Fellowships and Scholarships ,Intensive care medicine ,business ,Exercise - Abstract
Systemic sclerosis (SSc) is a heterogeneous multisystem autoimmune disease whereby its main pathological drivers of disability and damage are vascular injury, inflammatory cell infiltration, and fibrosis. These mechanisms result in diffuse and diverse impairments arising from ischemic circulatory dysfunction leading to painful skin ulceration and calcinosis, neurovascular aberrations hindering gastrointestinal (GI) motility, progressive painful, incapacitating or immobilizing effects of inflammatory and fibrotic effects on the lungs, skin, articular and periarticular structures, and muscle. SSc-related impairments impede routine activities of daily living (ADLs) and disrupt three critical life areas: work, family, social/leisure, and also impact on psychological well-being. Physical activity and exercise are globally recommended; however, for connective tissue diseases, this guidance carries greater impact on inflammatory disease manifestations, recovery, and cardiovascular health. Exercise, through myogenic and vascular phenomena, naturally targets key pathogenic drivers by downregulating multiple inflammatory and fibrotic pathways in serum and tissue, while increasing circulation and vascular repair. G-FoRSS, The Global Fellowship on Rehabilitation and Exercise in Systemic Sclerosis recognizes the scientific basis of and advocates for education and research of exercise as a systemic and targeted SSc disease-modifying treatment. An overview of biophysiological mechanisms of physical activity and exercise are herein imparted for patients, clinicians, and researchers, and applied to SSc disease mechanisms, manifestations, and impairment. A preliminary guidance on exercise in SSc, a research agenda, and the current state of research and outcome measures are set forth.
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- 2021
83. Improvement of PSO algorithm by memory based gradient search - application in inventory management.
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Tamás Varga, András Király, and János Abonyi
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- 2014
84. Outpatient rehabilitation programs for COVID-19 patients
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Mónika, Fekete, Zsófia, Szarvas, Vince, Fazekas-Pongor, Zsuzsanna, Kováts, Veronika, Müller, and János Tamás, Varga
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Hospitalization ,SARS-CoV-2 ,Outpatients ,Quality of Life ,COVID-19 ,Humans - Abstract
Összefoglaló. A COVID-19-fertőzésen átesett betegek közül többen elhúzódó panaszokról számolnak be a felépülést követően, sokaknál tartósan fennáll a köhögés, a nehézlégzés, a mellkasi fájdalom, a légszomj attól függetlenül, hogy enyhe vagy súlyosabb tüneteket okozott a koronavírus. A betegek erőtlennek érzik magukat, erős fáradtságérzetre panaszkodnak, míg mások gyomor-bél rendszeri panaszokra, fejfájásra, depresszióra, a szaglás- és ízérzékelés elvesztésére. Számtalan kutatás leírja, hogy a fertőzés még akár hónapokkal később is hatással lehet a tüdő működésére, és korábban egészséges tüdőn is látható a koronavírus-fertőzés a gyógyulás után három hónappal készült kontroll-mellkas-CT-leleten. Éppen ezért szükség van a fertőzés lezajlását követően tüdőgyógyászati kivizsgálásra, ha a betegnek elhúzódó panaszai vannak, vagy ha a betegség tüdőgyulladást okozott. Szükség van a jelenleg működő fekvőbeteg-légzőszervi rehabilitáció mellett a kezelés ambuláns kiterjesztésére is, melynek célja újabb kórházi ápolás nélkül a teljes gyógyulás elérése a betegeknél. A COVID-19-fertőzésen átesett betegeknél a komplex rehabilitáció hatására javul a terhelhetőség, az életminőség, javulnak a légzésfunkciós értékek, csökkennek a panaszok, javul a betegek fizikai és pszichikai állapota. Összefoglaló kutatásunk célja áttekinteni, hogy milyen COVID-19 ambuláns rehabilitációs programok indultak el a koronavírus-fertőzésen átesett betegek esetében nemzetközi és hazai színtereken. Orv Hetil. 22021; 162(42): 1671-1677. Summary. Several patients with COVID-19 infection report prolonged complaints after recovery and many of them suffer from persistent cough, dyspnea, chest pain and shortness of breath regardless of whether the coronavirus caused mild or more severe symptoms. They complain of severe fatigue and weakness while others grizzle about gastrointestinal complaints, headache, depression, loss of sense of smell and taste. Numerous studies describe that the infection can affect lung function even in months and coronavirus infection can be detectable in previously healthy lungs by taking a control chest CT scan three months after recovery. Therefore, chest follow-up is required after the infection if the patient has prolonged complaints or if the disease has caused pneumonia. In addition to the currently operating inpatient respiratory rehabilitation, there is also a need for an outpatient extension of treatment to achieve complete recovery in patients without further hospitalization. For those patients who have had the COVID-19 infection complex rehabilitation can improve their workload, quality of life, improves their respiratory function values, reduces their complaints and also improves their physical and mental condition. The aim of our summary research is to review what COVID-19 outpatient rehabilitation programs have been initiated for patients who went through coronavirus infection on international and domestic scenes. Orv Hetil. 2021; 162(42): 1671-1677.
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- 2021
85. Intracerebroventricularly Injected Streptozotocin Exerts Subtle Effects on the Cognitive Performance of Long-Evans Rats
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Zoltán S. Zádori, István Gyertyán, Brigitta Tekla Tajti, Attila Gáspár, Bence Tamás Varga, Barbara Hutka, and Aliz Judit Ernyey
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0301 basic medicine ,Serial reaction time ,medicine.medical_specialty ,STZ icv ,Tau protein ,RM1-950 ,03 medical and health sciences ,Lateral ventricles ,0302 clinical medicine ,Western blot ,learning impairment ,Internal medicine ,medicine ,Pharmacology (medical) ,Effects of sleep deprivation on cognitive performance ,Cognitive decline ,Original Research ,phospho-tau ,Pharmacology ,biology ,medicine.diagnostic_test ,business.industry ,β-amyloid ,medicine.disease ,Streptozotocin ,030104 developmental biology ,Endocrinology ,cognitive test battery ,biology.protein ,Alzheimer disease model ,Therapeutics. Pharmacology ,Alzheimer's disease ,business ,030217 neurology & neurosurgery ,medicine.drug - Abstract
Intracerebroventricularly injected streptozotocin (STZ)-induced learning impairment has been an increasingly used rat model of Alzheimer disease. The evoked pathological changes involve many symptoms of the human disease (cognitive decline, increase in β-amyloid and phospho-tau level, amyloid plaque-like deposits). However, the model has predominantly been used with Wistar rats in the literature. The objective of the current study was to transfer it to Long-Evans rats with the ulterior aim to integrate it in a complex cognitive test battery where we use this strain because of its superior cognitive capabilities. We performed two experiments (EXP1, EXP2) with three months old male animals. At EXP1, rats were treated with 2 × 1.5 mg/kg STZ (based on the literature) or citrate buffer vehicle injected bilaterally into the lateral ventricles on days 1 and 3. At EXP2 animals were treated with 3 × 1.5 mg/kg STZ or citrate buffer vehicle injected in the same way as in EXP1 at days 1, 3, and 5. Learning and memory capabilities of the rats were then tested in the following paradigms: five choice serial reaction time test (daily training, started from week 2 or 8 post surgery in Exp1 or Exp2, respectively, and lasting until the end of the experiment); novel object recognition (NOR) test (at week 8 or 14), passive avoidance (at week 11 or 6) and Morris water-maze (at week 14 or 6). 15 or 14 weeks after the STZ treatment animals were sacrificed and brain phospho-tau/tau protein ratio and β -amyloid level were determined by western blot technique. In EXP1 we could not find any significant difference between the treated and the control groups in any of the assays. In EXP2 we found significant impairment in the NOR test and elevated β-amyloid level in the STZ treated group in addition to slower learning of the five-choice paradigm and a trend for increased phospho-tau/tau ratio. Altogether our findings suggest that the Long-Evans strain may be less sensitive to the STZ treatment than the Wistar rats and higher doses may be needed to trigger pathological changes in these animals. The results also highlight the importance of strain diversity in modelling human diseases.
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- 2021
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86. Comparative Analysis of Silybum Marianum Fruit Extracts and Thyme Oil Samples Using NMR-based Multivariate Statistical Methods
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Tamás Varga, Imre Klebovich, and Márta Kraszni
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Pharmaceutical Science ,General Medicine - Published
- 2021
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87. Ameliorating schizophrenia-like symptoms in vasopressin deficient male Brattleboro rat by chronic antipsychotic treatment
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Bibiána Török, Dóra Zelena, Anna Fodor, Barbara Klausz, and János Tamás Varga
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Olanzapine ,Male ,medicine.medical_specialty ,Vasopressins ,Injections, Subcutaneous ,Drug Evaluation, Preclinical ,Internal medicine ,Genetic model ,medicine ,Haloperidol ,Animals ,Humans ,Social Behavior ,Clozapine ,Pharmacology ,Risperidone ,biology ,business.industry ,Rats, Brattleboro ,biology.organism_classification ,medicine.disease ,Brattleboro rat ,Rats ,Disease Models, Animal ,Endocrinology ,Schizophrenia ,Aripiprazole ,Rats, Transgenic ,business ,medicine.drug ,Antipsychotic Agents - Abstract
Due to its various function vasopressin has been associated with many psychiatric disorders, including schizophrenia. Our previous study confirmed that vasopressin-deficient (di/di) Brattleboro rat can be a good genetic model for schizophrenia. Our present aim was to confirm whether the treatment effects of marketed antipsychotics are similar in di/di rats to those seen in human schizophrenic patients. Chronic subcutaneous administration of aripiprazole (5 mg/kg), clozapine (1 mg/kg), haloperidol (0.1 mg/kg), olanzapine (0.3 mg/kg) or risperidone (0.25 mg/kg) was used for 15 days in control (+/+ Brattleboro) and di/di rats. Social discrimination, social avoidance and prepulse inhibition tests were conducted on day 1, 8 and 15 of the treatment. Vasopressin-deficient rats showed social memory- and sensorimotor gating deficit. All used antipsychotics successfully normalized the reduced prepulse inhibition of di/di animals. However, most were effective only after prolonged treatment. Aripiprazole, clozapine, and olanzapine normalized the social memory deficit, while the effects of haloperidol and risperidone were not unequivocal. All drugs reduced social interest to some extent both in control and in di/di animals, aripiprazole being the less implicated in this regard during the social avoidance test. The restoration of schizophrenia-like behavior by antipsychotic treatment further support the utility of the vasopressin-deficient Brattleboro rat as a good preclinical model. Reduced social interest might be a general side-effect of antipsychotics, and aripiprazole has the most favorable profile in this regard.
- Published
- 2021
88. Publisher Correction: Rapid 14C excursion at 3372-3371 BCE not observed at two different locations
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Matthew W. Salzer, Mihály Molnár, Lukas Wacker, Nicolas Brehm, Willy Tegel, Elemér László, Chris Baisan, Irina P. Panyushkina, A. J. Timothy Jull, and Tamás Varga
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Solar physics ,High-energy astrophysics ,Paleontology ,Multidisciplinary ,Science ,Excursion ,General Physics and Astronomy ,General Chemistry ,Publisher Correction ,General Biochemistry, Genetics and Molecular Biology ,Geology - Abstract
A Correction to this paper has been published: https://doi.org/10.1038/s41467-021-21647-w
- Published
- 2021
89. Perioperative Factor Concentrate Use is Associated With More Beneficial Outcomes and Reduced Complication Rates Compared With a Pure Blood Product-Based Strategy in Patients Undergoing Elective Cardiac Surgery: A Propensity Score-Matched Cohort Study
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János Gál, Tamás Varga, Eszter Tamáska, Endre Németh, Ajandek Eory, Zsolt Lang, Viktor Berzsenyi, Gergely Csikos, Kálmán Benke, Adam Soltesz, Gabriella Molnar, Béla Merkely, and Kristóf Rácz
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medicine.medical_specialty ,business.industry ,Blood Component Transfusion ,Perioperative ,medicine.disease ,Surgery ,Cardiac surgery ,Cohort Studies ,Red blood cell ,Plasma ,Anesthesiology and Pain Medicine ,medicine.anatomical_structure ,Blood product ,Hemostasis ,Propensity score matching ,Coagulopathy ,Medicine ,Humans ,Cardiac Surgical Procedures ,Cardiology and Cardiovascular Medicine ,Complication ,business ,Propensity Score ,Retrospective Studies - Abstract
The goal of this study was to compare factor concentrate (FC)-based and blood product-based hemostasis management of coagulopathy in cardiac surgical patients in terms of postoperative bleeding, required blood products, and outcome.Retrospective, propensity score-matched analysis.Single, tertiary, academic medical center.One hundred eighteen matched pairs of 433 consecutive patients scheduled for cardiac surgery in two isolated periods with distinct strategies of hemostasis management.Patients received either blood product-based (period I) or FC-based (period II) hemostasis management to treat perioperative coagulopathy.Patients treated with FC management experienced less postoperative blood loss (907 v 1,153 mL, p = 0.014) and required less red blood cell and fresh frozen plasma transfusion (2.3 v 3.7 units p0.0001, and 2.0 v 3.4 units p0.0001, respectively) compared with subjects in the blood product-based management group. The frequency of Stage 3 acute kidney injury and 30-day mortality rate were significantly higher in the blood product-based group than in the FC management group (6.8% v 0.8%, p = 0.016, and 7.2% v 0.8%, p = 0.022, respectively). FC management-related thromboembolic events were not registered. The FC strategy was associated with a 2.19-fold decrease in the odds of massive postoperative bleeding (p0.0001), a 2.56-fold decrease in the odds of polytransfusion (p0.0001), and a 13.16-fold decrease in the odds of early postoperative death (p = 0.003).FC-based versus blood product-based management is associated with reduced blood product needs and fewer complications, and was not linked to a higher frequency of thromboembolic events or a decrease in long-term survival in cardiac surgical patients developing perioperative coagulopathy and bleeding.
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- 2021
90. Radiocarbon in the atmospheric gases and PM
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Tamás, Varga, István, Major, Virág, Gergely, András, Lencsés, Tibor, Bujtás, A J Timothy, Jull, Mihály, Veres, and Mihály, Molnár
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Aerosols ,Air Pollutants ,Hungary ,Radiation Monitoring ,Nuclear Power Plants ,Gases ,Environmental Monitoring - Abstract
Our study shows a one-year-long, monthly integrated continuous monitoring campaign of gaseous radiocarbon emission and ambient air compared with 4 event-like, weekly (168 h) atmospheric aerosol radiocarbon data in every season of 2019, at 4 locations (n = 16 aerosol sample) around the Paks Nuclear Power Plant, Hungary. The study shows the first aerosol radiocarbon results around a nuclear power plant measured by accelerator mass spectrometry in Hungary. There was no dominant contribution detected in the atmospheric CO
- Published
- 2021
91. Rapid 14C excursion at 3372-3371 BCE not observed at two different locations
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Chris Baisan, Irina P. Panyushkina, Nicolas Brehm, Lukas Wacker, Elemér László, Willy Tegel, A. J. Timothy Jull, Matthew W. Salzer, Mihály Molnár, and Tamás Varga
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Solar physics ,High-energy astrophysics ,Paleontology ,Multidisciplinary ,Matters Arising ,Science ,Excursion ,General Physics and Astronomy ,General Chemistry ,General Biochemistry, Genetics and Molecular Biology ,Geology - Abstract
Nature Communications, 12 (1), ISSN:2041-1723
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- 2021
92. Gas Ion Source Performance of the EnvironMICADAS at HEKAL Laboratory, Debrecen, Hungary
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Martin Seiler, István Major, Mihály Molnár, Lukas Wacker, Anita Molnár, Katalin Hubay, Mihály Veres, Ádám Vas, Gergely Orsovszki, A. J. Timothy Jull, Tamás Varga, Botond Buró, Róbert Janovics, Marianna Mészáros, Titanilla Kertész, and Virág Gergely
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010506 paleontology ,Archeology ,060102 archaeology ,Instrumentation ,Sample (material) ,Analytical chemistry ,chemistry.chemical_element ,06 humanities and the arts ,01 natural sciences ,Ion source ,Isotopic composition ,Low energy ,chemistry ,Mixing ratio ,General Earth and Planetary Sciences ,Environmental science ,0601 history and archaeology ,Carbon ,0105 earth and related environmental sciences - Abstract
A coupled accelerator mass spectrometer–gas interface system has been successfully operating at the Hertelendi Laboratory of Environmental Studies, Debrecen, Hungary, since 2013. Over the last 6 years more than 500 gas targets were measured below 100 µg carbon content for carbon isotopic composition. The system was tested with blanks, OxII, IAEA-C1, IAEA-C2, and IAEA-C7 standards. The performance of our instrumentation shows good agreement with other published gas-interface system data and also shows a quite good agreement with the nominal value of international standard samples. There is a measurable but quite small memory effect after modern samples, but this does not significantly affect the final results. Typical ion currents at the low energy side were between 10–15 µA with a 5% CO2 in He mixing ratio. The relative errors average ±6% for samples greater than or equal to 10 µgC sample with mean count rates of 300 counts per microgram C for OxII. The blank is comparable with other systems, which is 0.0050 ± 0.0018 F14C or 34,000–47,000 yr BP, which allows for the routine measurement of both of small environmental and archeological samples.
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- 2021
93. An intercomparison project on 14C from single-year tree rings
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Tamás Varga, Sabrina G K Kudsk, Gregory W. L. Hodgins, Jessica A Nordby, Christoffer Karoff, Todd Lange, Jesper V. Olsen, Mihály Molnár, A. J. Timothy Jull, and Mads Faurschou Knudsen
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single-year measurement ,Archeology ,IntCal ,radiocarbon dating ,Individual data ,General Earth and Planetary Sciences ,Quality check ,Environmental science ,Physical geography ,Geometric mean ,tree ring ,intercomparison - Abstract
A laboratory intercomparison project was carried out on 20 annually resolved late-wood samples from the Danish oak record. The project included the following three laboratories: (1) the University of Arizona AMS Laboratory, University of Arizona, USA (AA); (2) HEKAL AMS Laboratory, MTA Atomki, Hungary (DeA); and (3) Aarhus AMS Centre (AARAMS), Aarhus University, Denmark (AAR). The large majority of individual data points (96%) lie within ±2σ of the weighted mean. Further assessment of the accuracy associated with the individual laboratories showed good agreement, indicating that consistent and reliable 14C measurements well in agreement with each other are produced at the three laboratories. However, the quoted analytical uncertainties appear to be underestimated when compared to the observed variance of differences from the geometric mean of the samples. This study provides a general quality check of the single-year tree-ring 14C measurements that are included in the new calibration curve.
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- 2021
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94. The effectiveness of pulmonary rehabilitation in connection with lung transplantation in Hungary
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Ferenc Rényi-Vámos, Jenő Elek, János Tamás Varga, Balázs Gieszer, Ildikó Madurka, Maria Kerti, Zsuzsanna Kovats, and Anikó Bohács
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medicine.medical_treatment ,03 medical and health sciences ,Grip strength ,FEV1/FVC ratio ,Pulmonary Disease, Chronic Obstructive ,0302 clinical medicine ,Forced Expiratory Volume ,Respiratory muscle ,Medicine ,Lung transplantation ,Humans ,Pulmonary rehabilitation ,030212 general & internal medicine ,Advanced and Specialized Nursing ,COPD ,Hungary ,Rehabilitation ,Bronchiectasis ,Hand Strength ,business.industry ,medicine.disease ,respiratory tract diseases ,Anesthesiology and Pain Medicine ,030228 respiratory system ,Anesthesia ,Quality of Life ,business ,Lung Transplantation - Abstract
BACKGROUND The role of pre- and post-lung transplant rehabilitation is to maintain or improve exercise tolerance, lung mechanics, peripheral and respiratory muscle function. Our aim was to measure the effectiveness of pre- and post-transplant rehabilitation in terms of the changes of functional and quality of life markers. METHODS Sixty-three patients (40 COPD FEV1: 21±5%pred, 18 IPF TLC: 42±13%pred, 4 bronchiectasis FEV1: 28±4%pred and 1 alveolitis fibrotisans TLC: 31%pred) participated in a pre- and 14 took part in a post-transplant rehabilitation program (more than 2 months after lung transplantation (LTx), primary diagnoses: 9 COPD, 4 IPF). The rehabilitation program consisted of chest-wall stretching, controlled breathing techniques and personalized exercise of 20-30 minutes by cycling and treadmill 2-3 times per day for 4 weeks. Seven functional and quality of life markers, like lung function, chest wall expansion (CWE), 6-minute walking distance (6MWD), modified Medical Research Council Dyspnea Scale (mMRC), COPD Assessment Test (CAT), breath holding time (BHT) and hand grip strength (HGS) were measured at the onset and the end of the rehabilitation program. The safety profile of the rehabilitation program was followed-up. RESULTS Pre-transplant pulmonary rehabilitation resulted in significant improvement in CWE (3.24±1.49 vs. 4.48±1.62 cm), CAT IQR {19 [13-25] vs. 15 [11-21]}, 6MWD (315±118 vs. 375±114 m), P
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- 2020
95. Maize Hybrid Response to Sustained Moderate Drought Stress Reveals Clues for Improved Management
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Jeffrey A. Coulter, Tamás Varga, Gary W. Feyereisen, Michael P. Russelle, and Samadangla Ao
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0106 biological sciences ,evapotranspiration ,engineering.material ,Biology ,maize ,01 natural sciences ,Acclimatization ,Crop ,lcsh:Agriculture ,Evapotranspiration ,crop coefficient ,Hybrid ,Phenology ,drought stress ,lcsh:S ,04 agricultural and veterinary sciences ,Crop coefficient ,Agronomy ,Productivity (ecology) ,040103 agronomy & agriculture ,engineering ,0401 agriculture, forestry, and fisheries ,water productivity ,Fertilizer ,Agronomy and Crop Science ,010606 plant biology & botany - Abstract
Crop water productivity (CWP), irrigation water productivity (IWP), actual seasonal basal crop coefficient (Kab), and actual crop evapotranspiration (ETa) are essential parameters for accurate estimation of crop water requirement to prevent irrigation water waste. These parameters were evaluated by conducting three experiments using a drought-tolerant maize hybrid and a non-drought-tolerant (&lsquo, standard&rsquo, ) maize hybrid receiving 50, 100, and 150% of the recommended optimal nitrogen (N) fertilizer rate and grown under well-watered conditions, drought stress from the 14 leaf collar maize phenological stage (V14) to maize physiological maturity (R6), and drought stress from the blister maize phenological stage (R2) to R6. Across hybrids, ETa decreased with increased duration of drought stress. The drought-tolerant hybrid had 7 and 8% greater CWP and IWP, respectively, compared to the standard hybrid when drought stress began at V14. Mid-season Kab was 1.08, 0.89, and 0.73 under well-watered conditions and when drought stress began at R2 and V14, respectively. These results reveal that (i) maize achieved more effective physiological acclimation with earlier exposure to drought stress, (ii) grain yield of the drought-tolerant hybrid was unchanged by earlier, compared to later, onset of drought despite a 10% decrease in ETa, and (iii) two phases of acclimation were identified: Maize Kab declined upon exposure to drought but stabilized as the crop acclimated.
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- 2020
96. A temporal model of territorial defence with antagonistic interactions
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Tamás Varga, József Garay, Jan Rychtář, and Mark Broom
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0106 biological sciences ,0301 basic medicine ,Energy (esotericism) ,Population ,Foraging ,Population Dynamics ,HB ,Evolutionary game theory ,Density dependence ,BF ,Territoriality ,HM ,010603 evolutionary biology ,01 natural sciences ,Time constraints ,03 medical and health sciences ,Territorial defence ,Time constraint ,Animals ,Economic geography ,Owner–intruder games ,education ,QA ,Ecology, Evolution, Behavior and Systematics ,Population Density ,education.field_of_study ,QL ,Patrolling ,030104 developmental biology ,Geography ,RC0321 - Abstract
Territorial behaviour is an important part of the lives of many animals. Once a territory has been acquired, an animal may spend its entire life on it, and may have to repeatedly defend it from conspecifics. Some species make great investments in the defence of a territory, and this defence can be costly, in terms of time, energy and risk of injury. Time costs in particular have rarely been explicitly factored into such models. In this paper we consider a model of territorial defence which includes both population dynamic and time delay elements, building upon recent advances in time constraint models. Populations may divide into two distinct types, where one type makes no effort to control territories. We shall call this type nomads, and the other type territorials. Here the territory owners must divide their time between patrolling and foraging, and this balance is their only strategic decision. We show how to find the evolutionarily stable patrolling strategy and the population composition of territorials and nomads, and consider some examples demonstrating key situations. We see that both time constraints and population density pressure are crucial to influencing behaviour. In particular we find cases with both territorial individuals and nomads where a mixed, either pure or both pure patrolling strategies are evolutionarily stable. In different conditions either nomads or territorials can be absent, and indeed for a significant range of parameter combinations the population can exhibit tristability, with three distinct ecologically stable population compositions: with both nomads and territorials, only nomads or only territorials.
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- 2020
97. Metabolic consequences of chronic obstructive pulmonary disease
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Mónika, Fekete, Vince, Fazekas-Pongor, Gergő, Szőllősi, and János Tamás, Varga
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Male ,Metabolic Syndrome ,Hungary ,Pulmonary Disease, Chronic Obstructive ,Cross-Sectional Studies ,Surveys and Questionnaires ,Quality of Life ,Humans ,Female ,Obesity ,Aged - Abstract
Összefoglaló. Bevezetés: Krónikus obstruktív tüdőbetegségben (COPD) az obesitas mellett a csökkent fizikai aktivitás nagymértékben fokozza a metabolikus szindróma kialakulásának valószínűségét. Célkitűzés: Kutatásunk célja volt felmérni a metabolikus szindróma prevalenciáját COPD-ben, valamint azt, hogy milyen mértékben függ össze az életkorral, a nemmel, a társbetegségekkel, a tüdőfunkció károsodásának mértékével, a tápláltsági állapottal, a fizikai terhelhetőséggel és az életminőséggel. Módszer: Keresztmetszeti vizsgálatot végeztünk az Országos Korányi Pulmonológiai Intézet Légzésrehabilitációs Osztályán fekvő betegek körében 2019. július 1. és december 31. között. A véletlenszerűen kiválasztott 300, 40 év feletti betegnek ismertük az antropometriai, légzésfunkciós vizsgálati eredményét és laboratóriumi paramétereit. Adatokat gyűjtöttünk a dohányzási szokásokról, az előző évi exacerbatiók számáról és a kortikoszteroidok használatáról is. Az életminőség mérésére a betegségspecifikus Szent György-féle Légzési Kérdőív magyar nyelvre validált változatát használtuk. A metabolikus szindrómát a Nemzetközi Diabetes Szövetség kritériumai alapján határoztuk meg. Eredmények: A metabolikus szindróma a betegek 72%-ánál fordult elő, férfi: 65,9% nő: 77,2% (p = 0,031). A metabolikus szindrómás betegek esetében rövidebb 6 perces sétatávolságot mértünk ([m] 250 [150-330] vs. 295 [162-360]; p = 0,384), és szignifikánsan több volt az előző évi exacerbatiók száma (3 [0-6] vs. 1 [1-2]; p0,001) a nem metabolikus szindrómás betegekhez képest. A BMI-re történő stratifikáció után a metabolikus szindróma jelenléte nagyobb volt BMI≥25 kg/m2 esetén. A hasi elhízás, a magas vérnyomás, a hyperlipidaemia és a hyperglykaemia szignifikánsan gyakoribb volt BMI≥25 kg/m2 esetén (p0,001). Következtetés: Eredményeink azt sugallják, hogy a metabolikus szindrómás betegekben megnő az együttes morbiditási index, különösen azok körében, akik túlsúlyosak vagy elhízottak. Ezért a COPD-s betegekben nagyon fontos időben felismerni és megfelelően kezelni a metabolikus szindrómát. Orv Hetil. 2021; 162(5): 185-191.Both obesity and the lack of physical activity among chronic obstructive pulmonary disease (COPD) patients increase the risk of developing metabolic syndrome.The goal of our study was to assess the prevalence of metabolic syndrome among COPD patients and to examine its correlation with age, gender, comorbidities, lung function values, nutritional status, exercise capacity, and quality of life.A cross-sectional study was performed at the Department of Pulmonary Rehabilitation of the Hungarian National Korányi Institute for Pulmonology between July 1st and December 31st, 2019. A total of 300 patients aged over 40 were selected at random. Anthropometric data were collected along with lung function values, laboratory parameters, smoking status, the number of exacerbations in the previous year, and the use of corticosteroids. Quality of life was measured by the validated Hungarian, COPD-specific Saint George Respiratory Questionnaire. Metabolic syndrome was defined according to the International Diabetes Federation criteria.Metabolic syndrome affected 72% of COPD patients (male: 65.9%, female 77.2%; p = 0.031). In patients with metabolic syndrome, shorter 6-minute walking distance was measured ([m] 250 [150-330] vs. 295 [162-360]; p = 0.384) and the number of exacerbations in the previous year was significantly higher (3 [0-6] vs. 1 [1-2]; p0.001) compared to patients with no metabolic syndrome. After stratification for BMI, metabolic syndrome was more frequent in the case of BMI≥25 kg/m2. Central adiposity, hypertension, hyperlipidemia, and hyperglycemia were also significantly more frequent among patients with BMI≥25 kg/m2 (p0.001).Our results suggest that the co-morbidity index increases in patients with metabolic syndrome, especially in overweight or obese patients. Therefore, early detection and appropriate treatment of metabolic syndrome in patients with COPD is very important. Orv Hetil. 2021; 162(5): 185-191.
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- 2020
98. The use of near-infrared spectroscopy for the evaluation of a 4-week rehabilitation program in patients with COPD
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Botond Szucs, János Tamás Varga, Mónika Fekete, and Mate Petrekanits
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COPD ,Rehabilitation ,business.industry ,medicine.medical_treatment ,Skeletal muscle ,Oxygenation ,Hemoglobin levels ,medicine.disease ,Microcirculation ,Grip strength ,medicine.anatomical_structure ,Physiology (medical) ,Anesthesia ,medicine ,In patient ,business - Abstract
Background Near-infrared spectroscopy (NIRS) technology can evaluate muscle metabolism and oxygenation. NIRS-based oximeters can measure skeletal muscle oxygen delivery and utilization during static and dynamic work non-invasively. Our goal was to assess the value and usability of NIRS technology in chronic obstructive pulmonary disease (COPD) rehabilitation program. Methods Forty patients with COPD participated in a 4-week inpatient rehabilitation program that included breathing exercises and personalized cycle/treadmill training adjusted to the functional capacity, physical activity and comorbidities of the patients. A NIRS muscle oxygen monitor was used to measure tissue oxygenation and hemoglobin levels. Total hemoglobin index, average muscle oxygenation, minimal and maximal muscle oxygenation were recorded before and after the rehabilitation program. Results Rehabilitation resulted improvement in 6 min walking distance (6MWD:335.3 ± 110. vs. 398.3 ± 126.2 m; P < 0.01), maximal inspiratory pressure (MIP: 57.7 ± 22.7 vs. 63.6 ± 18.0 cmH2O; P < 0.01), chest wall expansion (CWE: 2.84 ± 1.26 vs, 4.00 ± 1.76 cm; P < 0.01), breath hold time (BHT: 25.8 ± 10.6 vs. 29.2 ± 11.6 s; P < 0.01) and grip strength (GS: 24.9 ± 11.9 vs. 27.0 ± 11.4 kg; P < 0.01). Quality of life improvement was monitored by COPD Assessment Test (CAT: 17.00 ± 8.49 vs. 11.89 ± 7.3, P < 0.05). Total hemoglobin index (tHb: 12.8 ± 1.3% vs. 12.8 ± 1.4), average muscle oxygenation (SmO2: 67.5 ± 14.4% vs. 65.2 ± 20.4%) showed a tendency for improvement. Maximal muscle oxygenation decreased (SmO2 max: 98.0 ± 20.5% vs. 90.1 ± 14.3%; P < 0.01). Minimal muscle oxygenation increased (SmO2 min: 42.6 ± 12.6% vs. 54.8 ± 14.3%; P < 0.01). Conclusions NIRS results showed that muscle oxygenation and microcirculation can be described as a high-risk factor in COPD patients. The 4-week rehabilitation improves functional parameters, quality of life and tissue oxygenation levels in COPD patients.
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- 2020
99. Completion of thermal runaway criteria: Two new criteria to define runaway limits
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Tamás Varga and Alex Kummer
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Temperature control ,Thermal runaway ,Computer science ,Applied Mathematics ,General Chemical Engineering ,Nuclear engineering ,02 engineering and technology ,General Chemistry ,021001 nanoscience & nanotechnology ,Industrial and Manufacturing Engineering ,Reliability (semiconductor) ,020401 chemical engineering ,Safe operation ,0204 chemical engineering ,0210 nano-technology - Abstract
Safe operation of thermally sensitive chemical reactors remains a crucial engineering issue. Thermal runaway occurs mainly due to loss of temperature control, and many chemical accidents initiated by thermal runaway can be foreseen by an appropriate analysis of thermal process data. Thermal runaway criteria can be applied to determine the onset of runaway phenomena and safety boundary diagrams can be constructed. However, several runaway criteria exist, which define the runaway-and safe zones differently. In this work nine commonly applied thermal runaway criteria were analyzed and compared based on their critical curves. As a result of this analysis, two new criteria were developed. Reliability of the derived criteria were investigated, where the occurrence of real runaway was determined based on the number of indications applying different criteria. The two new criteria were tested in three general reaction systems and in case a complex problem, where feeding trajectory of fed-batch reactor was optimized applying new criteria as non-linear constraint. One of the new criteria shows the highest reliability in indication of runaway development from all investigated runaway criteria.
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- 2019
- Full Text
- View/download PDF
100. Process simulator assisted framework to support process safety analysis
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Tamás Varga and Alex Kummer
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Hazard (logic) ,Operability ,Computer science ,Process (engineering) ,Hazard and operability study ,General Chemical Engineering ,05 social sciences ,Energy Engineering and Power Technology ,02 engineering and technology ,Management Science and Operations Research ,Industrial and Manufacturing Engineering ,020401 chemical engineering ,Process safety ,Control and Systems Engineering ,Control theory ,0502 economics and business ,Process optimization ,050207 economics ,0204 chemical engineering ,Process simulation ,Safety, Risk, Reliability and Quality ,Simulation ,Food Science - Abstract
With improving industrial chemical technologies Hazard and Operability Analysis (HAZOP) becomes more difficult to perform, because the technologies become more integrated and complex. It is more difficult to explore all hazard events due to the more frequent operating point transition. Therefore the experts’ work becomes more and more complicated, it takes a long time to analyze thoroughly a chemical technology with respect to process safety. Applying dynamic HAZOP can help the experts to explore all hazard situations in a technology based on dynamic process simulation, therefore a framework for exploring hazard events is suggested in this work. The proposed framework works via OPC (Open Platform Communication) connection between MATLAB and Aspen HYSYS dynamic process simulator. Based on the OPC connection data from Aspen HYSYS can be efficiently analyzed, moreover process optimization can be performed with a wide range of algorithms implemented in MATLAB. Applying the proposed framework different malfunctions can be preprogrammed and the effects of malfunctions can be analyzed automatically, hence the spending time of HAZOP can be shortened. Concentration of cumene-hydroperoxide (CHP) in vacuum distillation column is chosen as a case study to show how the framework can be applied to analyze process safety related situations. The malfunctions are generated through controller failures with significant changes in setpoints.
- Published
- 2019
- Full Text
- View/download PDF
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