ORCID Profile
0000-0002-2469-7645
Current Organisation
Magyar Tudományos Akadémia Wigner Fizikai Kutatóközpont Szilárdtestfizikai és Optikai Intézet
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Publisher: Springer Science and Business Media LLC
Date: 24-03-2021
Publisher: AIP Publishing
Date: 03-12-2018
DOI: 10.1063/1.5053228
Abstract: The super-bandgap laser irradiation of the in situ prepared As-S chalcogenide films was found to cause drastic structural transformations and unexpected selective diffusion processes, leading to As enrichment on the nanolayer surface. Excitation energy dependent synchrotron radiation photoelectron spectroscopy showed complete reversibility of the molecular transformations and selective laser-driven mass transport during “laser irradiation”-“thermal annealing” cycles. Molecular modeling and density functional theory calculations performed on As-rich cage-like clusters built from basic structural units indicate that the underlying microscopic mechanism of laser induced transformations is connected with the realgar-pararealgar transition in the As-S structure. The detected changes in surface composition as well as the related local and molecular structural transformations are analyzed and a model is proposed and discussed in detail. It is suggested that the formation of a concentration gradient is a result of bond cleavage and molecular reorientation during transformations and anisotropic molecular diffusion.
Publisher: Elsevier BV
Date: 02-2015
Publisher: Frontiers Media SA
Date: 26-10-2021
DOI: 10.3389/FMOLB.2021.728273
Abstract: Introduction: Recombinant human erythropoietin (rHuEPO) administration studies involving transcriptomic approaches have demonstrated a gene expression signature that could aid blood doping detection. However, current anti-doping testing does not involve collecting whole blood into tubes with RNA preservative. This study investigated if whole blood in long-term storage and whole blood left over from standard hematological testing in short-term storage could be used for transcriptomic analysis despite lacking RNA preservation. Methods: Whole blood s les were collected from twelve and fourteen healthy nonathletic males, for long-term and short-term storage experiments. Long-term storage involved whole blood collected into Tempus™ tubes and K 2 EDTA tubes and subjected to long-term (i.e., ‒80°C) storage and RNA extracted. Short-term storage involved whole blood collected into K 2 EDTA tubes and stored at 4°C for 6‒48 h and then incubated at room temperature for 1 and 2 h prior to addition of RNA preservative. RNA quantity, purity, and integrity were analyzed in addition to RNA-Seq using the MGI DNBSEQ-G400 on RNA from both the short- and long-term storage studies. Genes presenting a fold change (FC) of & .1 or & ‒1.1 with p ≤ 0.05 for each comparison were considered differentially expressed. Microarray analysis using the Affymetrix GeneChip® Human Transcriptome 2.0 Array was additionally conducted on RNA from the short-term study with a false discovery ratio (FDR) of ≤0.05 and an FC of & .1 or & ‒1.1 applied to identify differentially expressed genes. Results: RNA quantity, purity, and integrity from whole blood subjected to short- and long-term storage were sufficient for gene expression analysis. Long-term storage: when comparing blood tubes with and without RNA preservation 4,058 transcripts (6% of coding and non-coding transcripts) were differentially expressed using microarray and 658 genes (3.4% of mapped genes) were differentially expressed using RNA-Seq. Short-term storage: mean RNA integrity and yield were not significantly different at any of the time points. RNA-Seq analysis revealed a very small number of differentially expressed genes (70 or 1.37% of mapped genes) when comparing s les stored between 6 and 48 h without RNA preservative. None of the genes previously identified in rHuEPO administration studies were differently expressed in either long- or short-term storage experiments. Conclusion: RNA quantity, purity, and integrity were not significantly compromised from short- or long-term storage in blood storage tubes lacking RNA stabilization, indicating that transcriptomic analysis could be conducted using anti-doping s les collected or biobanked without RNA preservation.
Publisher: Elsevier BV
Date: 07-2021
DOI: 10.1016/J.NMD.2021.04.007
Abstract: Exertional rhabdomyolysis may occur when an in idual is subjected to strenuous physical exercise. It is occasionally associated with myoglobinuria (i.e. "cola-colored" urine) alongside muscle pain and weakness. The pathophysiology of exertional rhabdomyolysis involves striated muscle damage and the release of cellular components into extracellular fluid and bloodstream. This can cause acute renal failure, electrolyte abnormalities, arrhythmias and potentially death. Exertional rhabdomyolysis is observed in high-performance athletes who are subjected to intense, repetitive and/or prolonged exercise but is also observed in untrained in iduals and highly trained or elite groups of military personnel. Several risk factors have been reported to increase the likelihood of the condition in athletes, including: viral infection, drug and alcohol abuse, exercise in intensely hot and humid environments, genetic polymorphisms (e.g. sickle cell trait and McArdle disease) and epigenetic modifications. This article reviews several of these risk factors and proposes screening protocols to identify in idual susceptibility to exertional rhabdomyolysis as well as the relevance of proteomics for the evaluation of potential biomarkers of muscle damage.
Publisher: AIP Publishing
Date: 14-12-2015
DOI: 10.1063/1.4937551
Abstract: As-deposited, annealed, and in situ As2S3 nanolayers, illuminated by blue (405 nm) and red (650 nm) laser light, were studied using synchrotron radiation photoelectron spectroscopy and DFT electronic structure calculations. Changes in composition and local atomic coordination occurring in the irradiated region of As2S3 films were monitored by analysis of As 3d and S 2p core levels. These studies show that both the thermal treatment and the red laser illumination of As2S3 nanolayers decrease the concentration of homopolar (As-As and S-S) bonds. From the other hand, an increasing concentration of As-rich structural units (s.u.) with a homopolar As-As bond was observed under in situ blue laser illumination of As2S3 nanolayers. Molecular orbital energies were calculated for different As- and S-centered s.u. and used for the interpretation of the core levels and valence band spectra. The surface local structure of the As2S3 nanolayers and its photoinduced transformation are discussed in detail.
Publisher: Springer Science and Business Media LLC
Date: 08-12-2020
Publisher: Springer Science and Business Media LLC
Date: 03-05-2023
DOI: 10.1186/S12920-023-01512-Z
Abstract: The effects of Anabolic Androgenic Steroids (AAS) are largely illustrated through Androgen Receptor induced gene transcription, yet RNA-Seq has yet to be conducted on human whole blood and skeletal muscle. Investigating the transcriptional signature of AAS in blood may aid AAS detection and in muscle further understanding of AAS induced hypertrophy. Males aged 20–42 were recruited and s led once: sedentary controls (C), resistance trained lifters (RT) and resistance trained current AAS users (RT-AS) who ceased exposure ≤ 2 or ≥ 10 weeks prior to s ling. RT-AS were s led twice as Returning Participants (RP) if AAS usage ceased for ≥ 18 weeks. RNA was extracted from whole blood and trapezius muscle s les. RNA libraries were sequenced twice, for validation purposes, on the DNBSEQ-G400RS with either standard or CoolMPS PE100 reagents following MGI protocols. Genes were considered differentially expressed with FDR 0.05 and a 1.2- fold change. Cross-comparison of both standard reagent whole blood (N = 55: C = 7, RT = 20, RT-AS ≤ 2 = 14, RT-AS ≥ 10 = 10, RP = 4 N = 46: C = 6, RT = 17, RT-AS ≤ 2 = 12, RT-AS ≥ 10 = 8, RP = 3) sequencing datasets, showed that no genes or gene sets athways were differentially expressed between time points for RP or between group comparisons of RT-AS ≤ 2 vs. C, RT, or RT-AS ≥ 10. Cross-comparison of both muscle (N = 51, C = 5, RT = 17, RT-AS ≤ 2 = 15, RT-AS ≥ 10 = 11, RP = 3) sequencing (one standard & one CoolMPS reagent) datasets, showed one gene, CHRDL1 , which has atrophying potential, was upregulated in RP visit two. In both muscle sequencing datasets, nine differentially expressed genes, overlapped with RT-AS ≤ 2 vs. RT and RT-AS ≤ 2 vs. C, but were not differentially expressed with RT vs. C, possibly suggesting they are from acute doping alone. No genes seemed to be differentially expressed in muscle after the long-term cessation of AAS, whereas a previous study found long term proteomic changes. A whole blood transcriptional signature of AAS doping was not identified. However, RNA-Seq of muscle has identified numerous differentially expressed genes with known impacts on hypertrophic processes that may further our understanding on AAS induced hypertrophy. Differences in training regimens in participant groupings may have influenced results. Future studies should focus on longitudinal s ling pre, during and post-AAS exposure to better control for confounding variables.
Publisher: Springer Science and Business Media LLC
Date: 07-01-2021
DOI: 10.1186/S40798-020-00293-4
Abstract: The pervasiveness of doping and findings of anti-doping corruption threaten weightlifting’s position at the 2024 Olympic Games. Analysing the practices of doping in weightlifters could identify patterns in doping that assist in future detection. We analysed publicly available data on sanctioned athletes/support personnel from the International Weightlifting Federation between 2008 and 2019 and announced retrospective Anti-Doping Rule Violations (ADRVs) from the 2008 and 2012 Olympic Games. There were 565 sanctions between 2008 and 2019 of which 82% related to the detection of exogenous Anabolic Androgenic Steroid (AAS) metabolites and markers indicating endogenous AAS usage. The detection of exogenous AAS metabolites, markers of endogenous AAS usage and other substance metabolites varied by IWF Continental Federation ( p ≤ 0.05) with Europe (74%, 11%, 15%) and Asia (70%, 15%, 15%) showing a higher detection of exogenous AAS compared to Pan America (37%, 30%, 33%) and Africa (50%, 17%, 33%). When looking at the 10 most detected substances, the nations with the highest number of sanctions (range 17–35) all had at least one overrepresented substance that accounted for 38–60% of all detected substances. The targeted re-analysis of s les from the 2008 and 2012 Olympic Games due to the discovery of long-term metabolites for exogenous AAS resulted in 61 weightlifters producing retrospective ADRVs. This includes 34 original medallists (9 gold, 10 silver and 15 bronze), the highest of any sport identified by Olympic Games s le re-testing. The exogenous AAS dehydrochloromethyltestosterone and stanozolol accounted for 83% of detected substances and were present in 95% of these s les. Based on these findings of regional differences in doping practices, weightlifting would benefit from the targeted testing of certain regions and continuing investment in long-term s le storage as the sensitivity and specificity of detection continues to improve.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 12-2018
DOI: 10.1249/JSR.0000000000000543
Abstract: One of the most contentious issues in modern day sport arises when sports are ided into male and female categories. The International Association of Athletics Federations’ (IAAF) previous policy regulating intersex athletes was suspended by the Court of Arbitration for Sport (CAS), resulting in a new policy. The challenge faced by the governing body of athletics is to formulate a policy that upholds both international law and the Olympic charter that stipulates athletes compete without discrimination of any kind. Implementation of the policy has been delayed until after a verdict, expected no later than March 26, 2019, in the Semenya versus IAAF trial in the Court of Arbitration for Sport. If the policy is enacted, it will restrict athletes from competing in the female athletics category with specific differences of sex development (DSD) in races from 400 m up to the mile in international level competitions unless they lower their natural testosterone (T) levels below 5 nmol·L −1 . To thoroughly assess this new IAAF policy, one needs to appreciate its legal, sociological, and scientific underpinnings but also the history of previous policies attempting to define precisely how athletes should be ided into male and female categories. We previously proposed a system to deal with gender variant athletes that relied on a determination of an “athlete/athletic gender.” The concept of “athlete gender” was presented to multiple audiences, and the resulting survey is included. A large majority of participants (71% of 153) who answered the survey agreed with the idea of an athlete gender. This position also was accompanied by the request for more studies (20% of those who agreed) and concern over the process of hormone monitoring (32% of those who agreed) to avoid doping misuse. The primary argument of those participating in the survey that disagreed with the position (23% of 153) was that biological differences between males and females remained even after the transition (47% of opposing comments). Mixed gender/sex competitions provide unique opportunities for athletes to compete against one another outside of the traditional male/female ide and pave the way for a more flexible approach for dealing with gender variant athletes.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 04-05-2022
Publisher: Springer Science and Business Media LLC
Date: 09-04-2021
Publisher: Springer Science and Business Media LLC
Date: 09-04-2021
Location: Hungary
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Alexander Kolliari-Turner.