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1.
J Pharm Biomed Anal ; 207: 114433, 2022 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-34715583

RESUMO

Selective androgen receptor modulators (SARMs) are a class of drugs presenting identical anabolic properties to anabolic steroids in addition to marked reduced androgenic effects. These drugs have emerged in the doping area within the early 2000's. Ligandrol, ostarine, RAD-140 and andarine are the most popular agents belonging to this class. According to the world anti-doping agency (WADA) prohibited list, SARMs are prohibited at all times (i.e. in and out-of-competition) and are listed under the section S1.2 (other anabolic agents). The compilation of the WADA testing figures reports from 2015 to 2019 has indicated a regular increase of adverse analytical findings (AAF) due to SARMs, particularly with ostarine and ligandrol. The implementation of highly sensitive chromatographic anti-doping analyses has induced high-profile challenges of anti-doping rules violations as athletes have claimed in numerous occasions that contamination was the reason for their AAF. Since the early 2000's, it has been accepted by the Court of Arbitration for Sports (CAS) in Lausanne (Switzerland) that, under some specific circumstances, unusual explanations can be provided to the Panel to explain an AAF. This was the open door for forensic investigations, as it is done in criminal Courts. A forensic approach can include testing for SARMs in food, drinks, but mostly in dietary supplements. As most anti-doping rules violations are only known several weeks after urine collection, this biological matrix is seldom use for further tests, despite the fact that most SARMs can be detected for several weeks in urine. Luckily, hair or nail testing can be a complement to document the claim of the athlete but of course, it cannot be considered as an alternative to urinalysis. This is because a negative hair or nail result cannot exclude the use of the detected drug and cannot overrule the urine result. To date, all methods for SARMs identification in various matrices involve liquid chromatography coupled to tandem mass spectrometry or high-resolution mass spectrometry. The aim of this paper is to review the scientific literature on the analytical possibilities of testing SARMs in dietary supplements, urine and hair or nail clippings after an AAF to document the claims of an athlete or his/her legal team.


Assuntos
Doping nos Esportes , Receptores Androgênicos , Atletas , Feminino , Humanos , Masculino , Detecção do Abuso de Substâncias , Espectrometria de Massas em Tandem
2.
Braz Oral Res ; 35: e110, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34816898

RESUMO

To evaluate the knowledge of Brazilian dentists of sports doping through the development, validation and application of the Brazilian Knowledge Scale about Sports Doping in Dentistry (B-KSSDD). A scale with 12 items was developed to assess a dentist's ability to determine whether the use of a medication characterised sports doping according to the World Anti-Doping Agency. A preliminary study to validate the B-KSSDD was carried out with 135 dentists, allowing the evaluation of ceiling and floor effects, convergent and discriminant validity, test-retest reliability and internal consistency of the instrument. A sample size calculation using the results of the preliminary study and the B-KSSDD was completed online using SurveyMonkey® by 270 participants from all regions of the country. The B-KSSDD showed evidence of convergent and discriminant validity, good temporal stability (ICC = 0.75) and internal consistency (alpha = 0.89). In the main study, the participants obtained an average score of 4.19/12 points on the B-KSSDD, suggesting that these professionals have insufficient knowledge about sports doping. The age of participants showed a negative association with knowledge about doping, while frequency of treating athletes and frequency of performing surgeries showed positive associations with knowledge about doping. The dentists had insufficient knowledge of the subject. Age of participants and frequency with which they attend to athletes are associated with knowledge about sports doping. Professional updating and education policies on doping are necessary for dentists, as athlete patients are at risk for severe sporting and financial penalties.


Assuntos
Doping nos Esportes , Esportes , Atletas , Odontologia , Humanos , Reprodutibilidade dos Testes , Inquéritos e Questionários
3.
Artigo em Inglês | MEDLINE | ID: mdl-34770044

RESUMO

Research evidence suggests that athletes' attitudes towards banned substances are among the strongest predictors of intention to use or actual practice of doping. Previous research has found that personal morality was negatively related to doping attitudes. However, less is known about the role of athletes' perceptions of fair play on their attitudes towards doping. First, we examined whether moral identity was associated with athletes' attitudes towards doping and whether their perceptions of fair play mediated this relationship. The second purpose was to determine whether these associations differed among non-athletes. Overall, 365 university students (49.9% males, 55.3% athletes) participated in this study (mean age 22.02, SD = 6.58). They completed questionnaires measuring the aforementioned variables. The results showed that athletes' moral identity and endorsement of fair play were negatively associated with their attitudes towards doping. The mediation analyses showed that the effect of moral identity on attitudes towards doping was partially mediated by perceptions of fair play (indirect effect, ß = -0.10, p < 0.05). Unlike student athletes, non-athletes' moral identity negatively predicted attitudes towards doping only indirectly, via fair play perception (indirect effect, ß = -0.08, p < 0.05). The study provides insights into how a person's morality and perception of moral values in sport may act as factors related to doping in sport. The practical implications for the promotion of anti-doping attitudes for athletes and separately for student non-athletes were provided together with future research perspectives.


Assuntos
Doping nos Esportes , Esportes , Adulto , Atletas , Atitude , Feminino , Humanos , Masculino , Princípios Morais , Percepção , Inquéritos e Questionários , Adulto Jovem
4.
Bioanalysis ; 13(19): 1511-1527, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34617444

RESUMO

The summer Olympic Games is the major mega sports event since the first modern era Olympiad, held in Athens, Greece in 1896. International Olympic Committee (IOC) has the responsibility of the organization of the summer and winter Games ensuring the broadcast in all corners of earth. The World Anti-Doping Agency (WADA) is the responsible organization of the fight against doping in sports. IOC and WADA support the event's country WADA Accredited Laboratory to incorporate the maximum of the new analytical technologies to become applicable during the event's antidoping testing. The current study reviewed the last 5 years progresses of the antidoping system with emphasis on the laboratory field.


Assuntos
Técnicas de Química Analítica , Doping nos Esportes/prevenção & controle , Humanos , Agências Internacionais , Laboratórios , Tóquio
5.
Molecules ; 26(20)2021 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-34684800

RESUMO

Androstenedione is a steroidal hormone produced in male and female gonads, as well as in the adrenal glands, and it is known for its key role in the production of estrogen and testosterone. Androstenedione is also sold as an oral supplement, that is being utilized to increase testosterone levels. Simply known as "andro" by athletes, it is commonly touted as a natural alternative to anabolic steroids. By boosting testosterone levels, it is thought to be an enhancer for athletic performance, build body muscles, reduce fats, increase energy, maintain healthy RBCs, and increase sexual performance. Nevertheless, several of these effects are not yet scientifically proven. Though commonly used as a supplement for body building, it is listed among performance-enhancing drugs (PEDs) which is banned by the World Anti-Doping Agency, as well as the International Olympic Committee. This review focuses on the action mechanism behind androstenedione's health effects, and further side effects including clinical features, populations at risk, pharmacokinetics, metabolism, and toxicokinetics. A review of androstenedione regulation in drug doping is also presented.


Assuntos
Androstenodiona/farmacologia , Anabolizantes/farmacologia , Androstenodiona/metabolismo , Androstenodiona/toxicidade , Animais , Atletas , Desempenho Atlético , Suplementos Nutricionais/toxicidade , Doping nos Esportes , Feminino , Humanos , Masculino , Fatores Sexuais , Testosterona/metabolismo
6.
Artigo em Inglês | MEDLINE | ID: mdl-34574458

RESUMO

In the fight against sports doping, the Athlete Biological Passport (ABP) system aims to indirectly unveil the doping incidents by monitoring selected biomarkers; however, several unexplored extrinsic factors may dampen a fair interpretation of ABP profiles. Chinese herbal medicine (CHM) plays a pivotal role in the health care system, and some remedies have a long history of being used to treat anaemia. In this study, we addressed the concerns of whether the CHM administration could yield a measurable effect on altering the ABP haematological variables. Forty-eight healthy volunteers were randomly assigned to receive two-week oral administration of one of the six selected CHM products that are commonly prescribed in Taiwan (eight subjects per group). Their blood variables were determined longitudinally in the phases of baseline, intervention, and recovery over 5 weeks. Blood collection and analyses were carried out in strict compliance with relevant operating guidelines. In the groups receiving Angelicae Sinensis Radix, Astragali Radix, and Salviae Miltiorrhizae Radix et Rhizoma, a significant increased reticulocyte percentage and decreased OFF-hr Score were manifested during the intervention, and such effects even sustained for a period of time after withdrawal. All other variables, including haemoglobin and Abnormal Blood Profile Score, did not generate statistical significance. Our results show that the use of CHM may impact the ABP haematological variables. As a consequence, we recommend athletes, particularly those who have been registered in the testing pool, should be aware of taking specific Chinese herbal-based treatment or supplementation, and document any of its usage on the anti-doping forms.


Assuntos
Doping nos Esportes , Medicamentos de Ervas Chinesas , Esportes , Atletas , Humanos , Detecção do Abuso de Substâncias
7.
Am J Pharm Educ ; 85(7): 8695, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34544745

RESUMO

The Tokyo Olympic and Paralympic Games in 2021 presented an opportunity for pharmacists to recognize the uniqueness of sports pharmacy as a developing field and to understand the importance of anti-doping education among patient-athletes. Patient-athletes make up a distinct patient population, and pharmacists are well positioned to support athletes' therapeutic decisions. Pharmacists need to be able to search for and interpret drug information to take care of this special population appropriately. The purpose of this commentary is to facilitate a discussion on what changes or reinforcement might help train pharmacists to become equipped with adequate knowledge and skills to support safe use of drugs among patient-athletes. While effective resources and tools have become more widely available, pharmacists' awareness of and training in the field of sports pharmacy continue to be needed. No matter where they practice, pharmacists should be ready to promote "the spirit of sport" and defend the importance of "clean" sport for their patient-athletes.


Assuntos
Doping nos Esportes , Educação em Farmácia , Esportes , Atletas , Humanos , Farmacêuticos
8.
Ned Tijdschr Geneeskd ; 1652021 05 17.
Artigo em Holandês | MEDLINE | ID: mdl-34346634

RESUMO

Furosemide is included in the World Anti-Doping Agency's (WADA) list of prohibited substances because it can be used by athletes to mask the presence of performance-enhancing drugs in urine and/or excrete water for rapid weight loss. But how effective is furosemide in masking prohibited substances in urine? Based on the pharmacology and the available literature, we conclude that the masking effect of furosemide is limited. Furosemide is a doping agent that is mainly relevant for sports with weight categories.


Assuntos
Doping nos Esportes , Substâncias para Melhoria do Desempenho , Esportes , Atletas , Furosemida , Humanos , Detecção do Abuso de Substâncias
9.
Anim Genet ; 52(5): 759-761, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34339052

RESUMO

Gene doping is prohibited in horseracing. In a previous study, we developed a method for non-targeted transgene detection using DELLY, which is based on split-read (SR) and paired-end (PE) algorithms to detect structural variants, on WGS data. In this study, we validated the detection sensitivity of DELLY using artificially generated sequence data of 12 target genes. With DELLY, at least one intron was detected as a deletion in eight targeted genes using the 150 bp PE read WGS data, whereas all targeted genes were detected by DELLY using the 100 bp PE read data. The detection sensitivity was higher in 100 bp PE reads than in 150 bp PE reads, despite a lower total sequence coverage, probably because of mismatch tolerance between the mapped reads and reference genome. In addition, it was observed that the average intron size detected by SR alone was 293 bp and that that detected by both SR and PE was 8924 bp. Thus, we showed that transgenes with various intron-exon structures could be detected using DELLY, suggesting its application in gene-doping control in horses.


Assuntos
Animais Geneticamente Modificados , Doping nos Esportes , Cavalos/genética , Íntrons , Esportes , Transgenes , Algoritmos , Animais , Éxons
10.
J Pharm Biomed Anal ; 205: 114312, 2021 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-34391136

RESUMO

Probing for evidence of the administration of prohibited therapeutics, drugs and/or drug candidates as well as the use of methods of doping in doping control samples is a central assignment of anti-doping laboratories. In order to accomplish the desired analytical sensitivity, retrospectivity, and comprehensiveness, a considerable portion of anti-doping research has been invested into studying metabolic biotransformation and elimination profiles of doping agents. As these doping agents include lower molecular mass drugs such as e.g. stimulants and anabolic androgenic steroids, some of which further necessitate the differentiation of their natural/endogenous or xenobiotic origin, but also higher molecular mass substances such as e.g. insulins, growth hormone, or siRNA/anti-sense oligonucleotides, a variety of different strategies towards the identification of employable and informative metabolites have been developed. In this review, approaches supporting the identification, characterization, and implementation of metabolites exemplified by means of selected doping agents into routine doping controls are presented, and challenges as well as solutions reported and published between 2010 and 2020 are discussed.


Assuntos
Anabolizantes , Doping nos Esportes , Preparações Farmacêuticas , Esportes , Humanos , Detecção do Abuso de Substâncias
11.
Water Sci Technol ; 84(3): 576-595, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34388120

RESUMO

Cu doped InVO4 (xCu-InVO4 (x = 0.06-0.15 wt %) was synthesized by a facile one-pot hydrothermal method for the removal of methylene blue (MB) under LED light irradiation. The X-ray photoelectron spectroscopy (XPS) analysis indicated the coexistence of V5+ and V4+ species due to the O-deficient nature of the xCu-InVO4. The synthesized photocatalysts displayed a morphology of spherical and square shaped particles (20-40 nm) and micro-sized rectangle rods with a length range of 100-200 µm. The xCu-InVO4 exhibited superior adsorption and photodegradation efficiency compared to pristine InVO4 and TiO2 due to the presence of O2 vacancies, V4+/V5+ species, and Cu dopant. The optimum reaction conditions were found to be 5 mg L-1 (MB concentration), pH 6, and 100 mg of photocatalyst mass with a removal efficiency and mineralization degree of 100% and 96.67%, respectively. The main active species responsible for the degradation of MB were •OH radicals and h+. Reusability studies indicated that the 0.13Cu-InVO4 was deactivated after a single cycle of photocatalytic reaction due to significant leaching of V4+ and Cu2+ species.


Assuntos
Doping nos Esportes , Catálise , Azul de Metileno , Fotólise , Titânio
12.
Psychiatr Clin North Am ; 44(3): 405-417, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34372997

RESUMO

The pressure to gain mass, power, explosiveness, and endurance and to obtain a performance edge continues to a part of sports. Anabolic agents, including selective androgen receptor modulators along with peptides, hormones, and metabolic modulators, continues to evolve. Methods to promote transcription to modify gene expression are a part of the evolution. In order to monitor and improve doping detection, the Athlete Biological Passport has been created. This article provides an up-to-date review of alcohol, anabolic androgens and related agents, stimulants, opioids, and cannabis and related compounds and their effects on athlete health and performance.


Assuntos
Anabolizantes , Estimulantes do Sistema Nervoso Central , Doping nos Esportes , Transtornos Relacionados ao Uso de Substâncias , Atletas , Humanos
13.
Sensors (Basel) ; 21(13)2021 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-34203318

RESUMO

Monitoring and detecting carbon monoxide (CO) are critical because this gas is toxic and harmful to the ecosystem. In this respect, designing high-performance gas sensors for CO detection is necessary. Zinc oxide-based materials are promising for use as CO sensors, owing to their good sensing response, electrical performance, cost-effectiveness, long-term stability, low power consumption, ease of manufacturing, chemical stability, and non-toxicity. Nevertheless, further progress in gas sensing requires improving the selectivity and sensitivity, and lowering the operating temperature. Recently, different strategies have been implemented to improve the sensitivity and selectivity of ZnO to CO, highlighting the doping of ZnO. Many studies concluded that doped ZnO demonstrates better sensing properties than those of undoped ZnO in detecting CO. Therefore, in this review, we analyze and discuss, in detail, the recent advances in doped ZnO for CO sensing applications. First, experimental studies on ZnO doped with transition metals, boron group elements, and alkaline earth metals as CO sensors are comprehensively reviewed. We then focused on analyzing theoretical and combined experimental-theoretical studies. Finally, we present the conclusions and some perspectives for future investigations in the context of advancements in CO sensing using doped ZnO, which include room-temperature gas sensing.


Assuntos
Doping nos Esportes , Óxido de Zinco , Monóxido de Carbono , Ecossistema , Temperatura
14.
Med Sci Sports Exerc ; 53(8): 1778-1794, 2021 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-34261998

RESUMO

This consensus statement is an update of the 1987 American College of Sports Medicine (ACSM) position stand on the use of anabolic-androgenic steroids (AAS). Substantial data have been collected since the previous position stand, and AAS use patterns have changed significantly. The ACSM acknowledges that lawful and ethical therapeutic use of AAS is now an accepted mainstream treatment for several clinical disorders; however, there is increased recognition that AAS are commonly used illicitly to enhance performance and appearance in several segments of the population, including competitive athletes. The illicit use of AAS by competitive athletes is contrary to the rules and ethics of many sport governing bodies. Thus, the ACSM deplores the illicit use of AAS for athletic and recreational purposes. This consensus statement provides a brief history of AAS use, an update on the science of how we now understand AAS to be working metabolically/biochemically, potential side effects, the prevalence of use among athletes, and the use of AAS in clinical scenarios.


Assuntos
Anabolizantes/administração & dosagem , Doping nos Esportes/legislação & jurisprudência , Hormônios Esteroides Gonadais/administração & dosagem , Atletas , Consenso , Humanos , Prevalência , Sociedades Médicas , Esportes , Medicina Esportiva
15.
Anal Chim Acta ; 1175: 338739, 2021 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-34330438

RESUMO

In the second part of this study, a systematic comparison was made between two ion fragmentation acquisition modes, namely data-independent acquisition (DIA) and DIA with ion mobility spectrometry (IMS) technology. These two approaches were applied to the analysis of 192 doping agents in urine. Group I included 102 compounds such as stimulants, diuretics, narcotics, and ß2-agonists, while Group II contained 90 compounds included steroids, glucocorticoids, and hormone and metabolic modulators. Important method parameters were examined and compared, including the fragmentation, sensitivity, and assignment capability with the minimum occurrence of false positive hits. The results differed between Group I and II in number of detected fragments when exploring the MS/MS spectra. In Group I only 13%, while in the Group II 64% of the substances had a higher number of fragments in DIA-IMS mode vs. DIA. In terms of sensitivity, the performance of the two modes with and without activated IMS dimension was identical for about 50% of the doping agents. The sensitivity was higher without IMS, i.e. in simple DIA mode, for 20-40% of remaining doping agents. Despite this sensitivity reduction with IMS, 82% of compounds from both Groups met the minimum required performance level (MRPL) criteria of the World Anti-Doping Agency (WADA) when the DIA-IMS mode was applied. Automated data processing is important in routine doping analysis. Therefore, processing methods were optimized and evaluated for the prevalence of false peak assignments by analysing the target substances at different concentrations in urine samples. Overall, a significantly higher number of misidentified compounds was observed in Group II, with an almost 2-fold higher number of misidentifications in DIA compared to DIA-IMS. This result highlights the benefit of the IMS dimension to reduce the rate of false positive in screening analysis. The optimized UHPLC-IM-HRMS method was finally applied to the analysis of urine samples from administration studies including nine doping agents from both Groups. However, to limit the number of interferences from the biological matrix, an emphasis is needed on the adequate settings of the data processing method.


Assuntos
Doping nos Esportes , Espectrometria de Mobilidade Iônica , Glucocorticoides , Entorpecentes , Esteroides , Espectrometria de Massas em Tandem
16.
J Pharm Biomed Anal ; 204: 114239, 2021 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-34252818

RESUMO

The determination of Human Chorionic Gonadotropin (HCG) in biological fluids is of great interest in the early pregnancy diagnostics, the evaluation of pregnancy disorders, as a tumor marker, as a screening procedure for anti-doping control, and many other purposes. A simple sandwich-type UltraMicro Enzyme-Linked ImmunoSorbent Assay (UMELISA) has been developed for the measurement of HCG in serum and urine samples. Strips coated with a high affinity MAb directed against HCG are used as solid phase, to ensure the specificity of the assay. The HCG assay was completed in 1.5 h, with a measuring range of 0.76-400 mIU/mL. The intra- and inter-assay coefficients of variation were lower than 10 %, depending on the HCG concentrations evaluated. Recovery percentages were 96.43-97.16 % (serum) and 98.10-99.04 % (urine). The assay detected intact HCG, nicked HCG, HCG ß, and nicked HCG ß, and did not recognize any of the interfering molecules tested. Regression analysis showed a good correlation with Elecsys in serum (n = 1459, r = 0.952, ρc = 0.948) and urine (n = 869, r = 0.988, ρc = 0.978). A good correlation was also found with 84 RIQAS samples analyzed with the kits Elecsys (r = 0.969, ρc = 0.957), Architect (r = 0.982, ρc = 0.970), Dimension (r = 0.989, ρc = 0.977), and Bioscience (r = 0.992, ρc = 0.980), all with a p < 0.01. Comparison with transvaginal ultrasonography in early pregnancy detection showed a specificity and a sensitivity of 100 % (n = 2385, κ = 1). The analytical performance characteristics of UMELISA HCG endorse its use for the quantification of HCG in serum and urine samples. This assay will make a cost-effective diagnostic kit accessible to low-income countries and is now available in the Cuban Public Health System.


Assuntos
Gonadotropina Coriônica , Doping nos Esportes , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Imunoensaio , Gravidez
17.
Artigo em Inglês | MEDLINE | ID: mdl-34229166

RESUMO

Anti-doping substances listed by the World Anti-Doping Agency (WADA) include hundreds of compounds of very different physico-chemical properties. Anti-doping control laboratories need to screen all these substances in the so-called Initial Testing Procedures (ITPs) what is very challenging from an analytical point of view. ITPs are mostly based on reversed-phase (RP) liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) using C18 columns, which feature poor retention and peak tailing for polar and basic compounds, respectively. While studies on this field dealing with the comparison of stationary phases are focused on certain chemical classes, this research provides a wide multi-target approach. For this purpose, a representative group of 93 anti-doping agents (log P from -2.4 to 9.2) included in ten different classes of prohibited substances was selected. A comprehensive study on the performance of six columns and four eluents on different separation parameters (retention factors, asymmetry factors, co-elutions, total run times) and matrix effects (signal enhancement or suppression) was performed for LC-MS/MS-based ITPs. Columns working in both RP [C18, C8, phenyl hexyl (PH), pentafluorophenyl (PFP) and mixed-mode hydrophilic/RP (HILIC-RP)) and hydrophilic (HILIC)] modes were investigated. Eluents contained methanol or acetonitrile as organic modifiers, with or without the addition of ammonium acetate. The best column-mobile phase binomial for ITPs was PFP using water-methanol (0.1% formic acid) as eluent, while HILIC was the best option for highly polar non-aromatic anti-doping agents, which were poorly addressed by PFP. Excellent good peak shapes and relative acceptable matrix interferences were obtained for HILIC-RP, which was tested for the first time for the analysis of anti-doping agents, although the number of compounds eluting too fast was too high. On the whole, the alkyl phase C18 showed the worst performance and although C8 and PH were better, their performance did not surpass that of PFP. Possible retention mechanisms underlying separation in the different stationary phases were discussed. This research provides valuable information to anti-doping control labs for improving LC-MS/MS-based ITPs and it proposes PFP as a suitable alternative to the already established C18.


Assuntos
Cromatografia Líquida/métodos , Doping nos Esportes , Drogas Ilícitas , Espectrometria de Massas em Tandem/métodos , Humanos , Interações Hidrofóbicas e Hidrofílicas , Drogas Ilícitas/química , Drogas Ilícitas/urina
18.
J Nanosci Nanotechnol ; 21(12): 6120-6125, 2021 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-34229812

RESUMO

The Zn3V3O8 was synthesized by solvothermal method combined with heat treatment using Zn(NO3)3 · 6H2O and NH4VO3 as raw materials. The Zn3V3O8 was doped by Co2+ to form Zn2.88Co0.12V3O8. The samples were characterized by X-ray diffraction and scanning electron microscopy techniques. Electrochemical tests showed that the initial discharge specific capacity for Zn2.88Co0.12V3O8 was 640.4 mAh·g-1 when the current density was 100 mA·g-1, which was higher than that of pure Zn3V3O8 (563.5 mAh · g-1). After 80 cycles, the discharge specific capacity of Zn2.88Co0.12V3O8 could maintain at 652.2 mAh · g-1, which was higher than that of pure Zn3V3O8 (566.8 mAh·g-1) under same condition. The Zn2.88Co0.12V3O8 owned better rate performances than those of pure Zn3V3O8 also. The related modification mechanisms were discussed in this paper.


Assuntos
Doping nos Esportes , Microscopia Eletrônica de Varredura , Difração de Raios X
19.
J Mol Graph Model ; 107: 107982, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34237664

RESUMO

Graphene, having a perfect two-dimensional crystal structure, has many excellent features such as a high specific surface area, and extraordinary electrical, thermal and mechanical properties. However, its usage in electronic devices is possible only if band gap of desired value is induced in this gapless semi-metal. Therefore, first principle calculations have been carried out to investigate the role of oxygen (O) doping versus adsorption and, the impurity concentration and coverage to induce band gap in graphene employing PBE at GGA level. The band gap is induced owing to production of vacancies, dissociative adsorption of oxygen, subsituational doping and pre-dissociated oxygen adsorption. It is interesting to note that band gap is introduced by both the processes of doping and adsorption of O. The oxygen doping leads to induction of two energy gaps, smaller in value above and larger below the Fermi level; while adsorption irrespective of adsorption configuration produces single direct gap. Increase both in concentration and coverage leads to enhance band gap value maximum being 1.85 eV in case of hexagonal doping of 12.5% concentration with an exception in adsorption case. The results allow us to conclude that adsorption is as useful as doping to tune the band gap in graphene enabling its applications in designing high performance electronic devices.


Assuntos
Doping nos Esportes , Grafite , Adsorção , Teoria da Densidade Funcional , Oxigênio
20.
J Sports Med Phys Fitness ; 61(8): 1173-1183, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34256541

RESUMO

The coronavirus disease (COVID-19) pandemic has had an unprecedent impact on the world of sport and society at large. Many of the challenges with respect to integrity previously facing competitive sport have been accentuated further during the pandemic. Threats to the integrity of sporting competition include traditional doping, issues of technological fairness, and integration of transgender and intersex athletes in elite sport. The enforced lull in competitive sport provides an unprecedented opportunity for stakeholders in sport to focus on unresolved integrity issues and develop and implement long-lasting solutions. There needs to be a concerted effort to focus on the many technological innovations accelerated by and perfected during COVID-19 that have enabled us to work from home, such as teaching students on-line, applications for medical advice, prescriptions and referrals, and treating patients in hospitals/care homes via video links and use these developments and innovations to enhance sport integrity and anti-doping procedures. Positive sports integrity actions will require a considered application of all such technology, as well as the inclusion of "omics" technology, big data, bioinformatics and machine learning/artificial intelligence approaches to modernize sport. Applications include protecting the health of athletes, considered non-discriminative integration of athletes into elite sport, intelligent remote testing to improve the frequency of anti-doping tests, detection windows, and the potential combination with omics technology to improve the tests' sensitivity and specificity in order to protect clean athletes and deter doping practices.


Assuntos
COVID-19 , Doping nos Esportes , Inteligência Artificial , Atletas , Humanos , Pandemias , SARS-CoV-2
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