Acute Effects of Different Set Configurations on Neuromuscular, Metabolic, and Perceptual Responses in Young Women.

We compared neuromuscular, metabolic, and perceptual responses between different resistance training configurations in young women. In a counterbalanced randomized order, 13 young women performed the following protocols in separate sessions (sets x repetitions): traditional (TRAD): 5x10, 90-s of rest interval between sets; more frequent and shorter total rest (FSR): 10x5, 30-s of rest interval between sets. The sessions were composed of leg press exercise with the same intensity. Force (maximum voluntary isometric contraction [MVIC]) and metabolic (lactate concentration) responses were measured pre- and post-resistance training sessions. The rating of perceived exertion (RPE) was measured after each set. The internal training load was calculated using the session-RPE method. There was a significant reduction in the MVIC only after TRAD configuration (Effect size [ES] = 0.36). The lactate concentration increased in both conditions but was higher after TRAD (ES = 2.81) than FSR (ES = 1.23). The RPE has progressively increased in both configurations. On the other hand, the internal training load was lower in the FSR configuration. From our findings, we suggest that more frequent and shorter total rest is an effective strategy for maintaining the ability to produce force, generating less metabolic stress and lower perceived internal load in young women.

Racism, xenophobia, discrimination, and the determination of health.

This Series shows how racism, xenophobia, discrimination, and the structures that support them are detrimental to health. In this first Series paper, we describe the conceptual model used throughout the Series and the underlying principles and definitions. We explore concepts of epistemic injustice, biological experimentation, and misconceptions about race using a historical lens. We focus on the core structural factors of separation and hierarchical power that permeate society and result in the negative health consequences we see. We are at a crucial moment in history, as populist leaders pushing the politics of hate have become more powerful in several countries. These leaders exploit racism, xenophobia, and other forms of discrimination to divide and control populations, with immediate and long-term consequences for both individual and population health. The COVID-19 pandemic and transnational racial justice movements have brought renewed attention to persisting structural racial injustice.

Magnetic Field Manipulation of Tetrahedral Units in Spinel Oxides for Boosting Water Oxidation.

Magnetic field enhanced electrocatalysis has recently emerged as a promising strategy for the development of a viable and sustainable hydrogen economy via water oxidation. Generally, the effects of magnetic field enhanced electrocatalysis are complex including magnetothermal, magnetohydrodynamic and spin selectivity effects. However, the exploration of magnetic field effect on the structure regulation of electrocatalyst is still unclear whereas is also essential for underpinning the mechanism of magnetic enhancement on the electrocatalytic oxygen evolution reaction (OER) process. Here, it is identified that in a mixed NiFe2 O4 (NFO), a large magnetic field can force the Ni2+ cations to migrate from the octahedral (Oh ) sites to tetrahedral (Td ) sites. As a result, the magnetized NFO electrocatalyst (NFO-M) shows a two-fold higher current density than that of the pristine NFO in alkaline electrolytes. The OER enhancement of NFO is also observed at 1 T (NFO@1T) under an operando magnetic field. Our first-principles calculations further confirm the mechanism of magnetic field driven structure regulation and resultant OER enhancement. These findings provide a strategy of manipulating tetrahedral units of spinel oxides by a magnetic field on boosting OER performance.

Abrading bulk metal into single atoms.

Single-atom catalysts have recently attracted considerable attention because of their highly efficient metal utilization and unique properties. Finding a green, facile method to synthesize them is key to their widespread commercialization. Here we show that single-atom catalysts (including iron, cobalt, nickel and copper) can be prepared via a top-down abrasion method, in which the bulk metal is directly atomized onto different supports, such as carbon frameworks, oxides and nitrides. The level of metal loading can be easily tuned by changing the abrasion rate. No synthetic chemicals, solvents or even water were used in the process and no by-products or waste were generated. The underlying reaction mechanism involves the mechanochemical force in situ generating defects on the supports, then trapping and stably sequestering atomized metals.

Iron Single Atom Catalyzed Quinoline Synthesis.

The production of high-value chemicals by single-atom catalysis is an attractive proposition for industry owing to its remarkable selectivity. Successful demonstrations to date are mostly based on gas-phase reactions, and reports on liquid-phase catalysis are relatively sparse owing to the insufficient activation of reactants by single-atom catalysts (SACs), as well as, their instability in solution. Here, mechanically strong, hierarchically porous carbon plates are developed for the immobilization of SACs to enhance catalytic activity and stability. The carbon-based SACs exhibit excellent activity and selectivity (≈68%) for the synthesis of substituted quinolines by a three-component oxidative cyclization, affording a wide assortment of quinolines (23 examples) from anilines and acetophenones feedstock in an efficient, atom-economical manner. Particularly, a Cavosonstat derivative can be synthesized through a one-step, Fe1 -catalyzed cyclization instead of traditional Suzuki coupling. The strategy is also applicable to the deuteration of quinolines at the fourth position, which is challenging by conventional methods. The synthetic utility of the carbon-based SAC, together with its reusability and scalability, renders it promising for industrial scale catalysis.

Spin-orbit coupling suppression and singlet-state blocking of spin-triplet Cooper pairs.

An inhomogeneous magnetic exchange field at a superconductor/ferromagnet interface converts spin-singlet Cooper pairs to a spin-polarized triplet state. Although the decay envelope of triplet pairs within ferromagnetic materials is well studied, little is known about their decay in nonmagnetic metals and superconductors and, in particular, in the presence of spin-orbit coupling (SOC). Here, we investigate devices in which singlet and triplet supercurrents propagate into the s-wave superconductor Nb. In the normal state of Nb, triplet supercurrents decay over a distance of 5 nm, which is an order of magnitude smaller than the decay of spin-singlet pairs due to the SOC. In the superconducting state of Nb, triplet supercurrents are not able to couple with the singlet wave function and are thus blocked by the absence of available equilibrium states in the singlet gap. The results offer insight into the dynamics between s-wave singlet and s-wave triplet states.

Paramagnetic Conducting Metal-Organic Frameworks with Three-Dimensional Structure.

3D well-crystallized metal-organic frameworks (MOFs), M-THBQ (M=Fe, Co, Mn, THBQ=tetrahydroxybenzoquinone), are synthesized and characterized. Their structures are determined as cubic cell in the group of Pm 3 ‾ from powder X-ray diffraction data, and their properties of electronic, magnetic and spectroscopic are also investigated. They are all semiconductors, and Fe-THBQ exhibits the air-stable n-type thermoelectric characteristic as its Seebeck coefficient reaches -130 µV K-1 , and the electrical conductivity is 2.7×10-4  S cm-1 at 300 K. Additional, M-THBQ are paramagnetic, and the value of Weiss constant of Fe-THBQ is -219.37 K, indicating the existence of robust intramolecular antiferromagnetic exchanges. Meanwhile, they display strong absorption bands in the range of 220 to 1000 nm, suggest M-THBQ could have the potential to become photoabsorbers, and Fe-THBQ exhibits a narrow band gap of 0.63 eV according to the ultraviolet absorption edge spectrum.

Does rest interval between sets affect resistance training volume, density, and rating of perceived exertion when adopting the crescent pyramid system in young women?

BACKGROUND: The rest interval between sets can affect the responses to resistance training. Thus, the purpose of this study was to compare the effects of different rest intervals (RI) on volume, density, and rating of perceived exertion (RPE) when adopting a crescent pyramid (CP) system. METHODS: Twenty young women (21.1±2.6 years, 1.59±0.06 m, 58.5±9.3 kg) participated in this study. All participants performed three experimental sessions of the leg press exercise in 5 sets until voluntary muscular failure at 60%, 65%, 70%, 75%, and 80% of one-repetition maximum (1RM). A randomized and crossover design was used so that in each session one of three RI (RI-1 = 1 min, RI-2 = 2 min, and RI-3 = 3 min) was tested. RESULTS: The participants performed a significantly larger volume in the RI-3 (12820±3134 kg) when compared to RI-1 (10367±3053 kg) condition (P<0.05). The volume did not differ between RI-2 and RI-3 (P>0.05). The density was higher (P<0.05) in RI-1 (43.1±12.7 kg/s) when compared RI-2 (25.6±5.8 kg/s) and RI-3 (17.7±4.3 kg/s). The RI-2 presented higher density compared to RI-3 condition (P<0.05). The RPE was not different between the three conditions (P>0.05). CONCLUSIONS: The use of 2 minutes of rest between sets allowed the performance of a high volume-load and density of the session in young women. In addition, the three experimental sessions provided a high perception of effort.

Existe associação entre nível de atividade física e composição corporal em adolescentes? / Is there an association between level physical activity and body composition of adolescents?

Os objetivos do presente estudo foram (i) testar se existe associação e (ii) diferença entre o nível de atividade física (NAF) e composição corporal de adolescentes de escolas públicas e p riv adas. Participaram do presente estudo 84 adolescentes (feminino: n = 52; 61,9% e masculino: n = 3 2 ; 3 8 ,1 %) com idade média de 16,4 ± 0,8 anos (feminino = 16,5±0,8 anos e masculino 16,4 ± 0,8 anos) regularmente matriculados em uma escola pública e uma privada do município de Fortaleza/CE. O NAF foi quantificado por meio da aplicação do o questionário de atividade física para adolescentes. Posteriormente foram obtidos dados (massa corporal e estatura) para cálculo do índice de massa corporal (IMC). O percentual de gordura (%G) foi estimado de acordo com o sexo. O teste de correlação de Pea rso n foi utilizado para verificar associação entre as variáveis. Para comparação entre estudantes de escolas públicas e privadas, utilizamos as diferenças de médias estandardizadas, intervalo de co n fiança (90 %), tamanho do efeito e probabilidades de haver diferenças. Não encontramos associações significantes en tre o NAF e IMC (r = 0,033 à 0,214; p > 0,05) e NAF e %G (r = - 0,199 à 0,310; p > 0,05). Não h ouv eram diferenças substanciais entre estudantes de escolas pública e privada para NAF e variáveis de composição corporal. A falta de associação forte entre NAF e composição corporal aponta para o caráter multifatorial que perpassa a relação entre essas duas variáveis na população jovem. Adicionalmente, estudar em escola pública ou privada parece não afetar o NAF e a composição corporal de adolescentes...(AU)

The objectives of present study were (i) to test if there is an association and (ii) differen ce between the level of physical activity (LPA) and body composition of adolescents from public and private schools. A total of 84 adolescents (female: n = 52, 61.9% and males: n = 32, 38.1%), with a mean age o f .4 ± 0.8 years (female = 16.5 ± 0, 8 years and male 16.4 ± 0.8 years) regularly enrolled in a public an d private school in the municipality of Fortaleza/CE. NAF was quantified through the ap p lication o f t he physical activity questionnaire for adolescents. Subsequently data were obtained (body mass and height) to calculate the body mass index (BMI). The percentage of body fat (% BF) was estimated according to sex . The Pearson correlation test was used to verify association between the variables. For comparison between public and private school students, we used the differences of standardized means, co nfiden ce in terv al (90%), effect size and probability of differences. We did not find significant associations bet ween LPA and BMI (r = 0.033 to 0.214; p> 0.05) and LPA and % BF (r = - 0.19 to 0.310; p> 0.05). There were n o substantial differences between public and private school students for LPA and body co mpo sition. The lack of strong association between NAF and body composition points to the multifactorial character t hat per passes the relationship between these two variables in the young population. Additionally, studying in a public or private school does not seem to affect LPA and the body composition of adolescents...(AU)

Body fat percentage and lower limbs temperature in recreational cyclists during an incremental test / Porcentagem de gordura e temperatura dos membros inferiores em ciclistas recreativos durante teste incremental

This study aimed to evaluate temperature variations on the thighs in an incremental cycling test in healthy recreational cyclists with two different fat percentages. Thirty-two male recreational cyclists were measured in height, body mass, thigh skinfold and body fat percentage, and from the body fat percentage were divided into two groups, Group 1: 16 cyclists who presented body fat percentage < 24% and Group 2: 16 cyclists who presented body fat percentage > 24%. Three thermographic photos were taken, before (Pre), just after (Post) and after 10 min (Post10) of the incremental cycling test to determine mean temperature of right and left Vastus Lateralis, Rectus Femoris and Biceps Femoris. Temperature variations were defined as the difference among the three moments: (i) var1 = Post-Pre, (ii) var2 = Post10- Pre and (iii) var3 = Post10-Post. Differences between groups and moments were calculated using magnitude-based inferences. Group 1 evidenced a very likely large increase in the cycling peak power output. Group 2 showed a likely and most likely moderate, large and very large increase in age, body mass and fat. Group 1 depicted a very likely to likely moderate temperature increase in the right and left Vastus Lateralis, Rectus Femoris and Biceps Femoris on Post10 compared to Post effort moment. Both groups depicted a very likely and most likely moderate and large temperature decrease of right and left Biceps Femoris on Pre compared to Post effort. Percentage of fat seems to discreetly influence skin temperature response, finding that might not be observed when we evaluate trained cyclists exhibiting different percentages of fat....(AU)

Este estudo objetivou a avaliar as variações de temperatura das coxas em um teste incremental de ciclismo em ciclistas recreacionais saudáveis com dois diferentes percentuais de gordura. Trinta e dois ciclistas recreacionais do sexo masculino foram avaliados em estatura, massa corporal, dobras cutâneas da coxa e percentual de gordura corporal, e, a partir do percentual de gordura corporal, foram divididos em dois grupos, Grupo 1: 16 ciclistas que apresentaram percentual de gordura corporal < 24% e Grupo 2: 16 ciclistas que apresentaram percentual de gordura corporal > 24%. Foram tiradas três fotos termográficas, antes (Pré), logo após (Pós) e após 10 min (Pós10) do teste de ciclismo para determinar a temperatura média do Vasto Lateral, Reto Femoral e Bíceps Femoral direito e esquerdo. As variações de temperatura foram definidas como a diferença entre os três momentos: (i) var1 = Pós-Pré, (ii) var2= Pós10-Pré e (iii) var3= Pós10-Pós. Diferenças entre grupos e momentos foram calculadas usando inferências baseadas em magnitude. Grupo 1 apresentou um provável a muito provável aumento moderado da temperatura para os Vastos Laterais direito e esquerdo, o Reto Femoral e o Bíceps Femoral no Pós10 em comparação com o momento pós-esforço. Grupo 2 mostrou aumentos provável e muito provável moderado, grande e muito grande na idade, massa corporal e gordura. Ambos os grupos descreveram uma muito provável e mais provável moderada e grande queda de temperatura do Bíceps Femoral direito e esquerdo no Pré comparado ao Pós-esforço. Percentagem de gordura parece influenciar discretamente a resposta da temperatura da pele, resultado que poderá não ser observado quando avaliados ciclistas treinados que apresentam diferentes percentagens de gordura....(AU)

Enhanced oxygen reduction with single-atomic-site iron catalysts for a zinc-air battery and hydrogen-air fuel cell.

Efficient, durable and inexpensive electrocatalysts that accelerate sluggish oxygen reduction reaction kinetics and achieve high-performance are highly desirable. Here we develop a strategy to fabricate a catalyst comprised of single iron atomic sites supported on a nitrogen, phosphorus and sulfur co-doped hollow carbon polyhedron from a metal-organic framework@polymer composite. The polymer-based coating facilitates the construction of a hollow structure via the Kirkendall effect and electronic modulation of an active metal center by long-range interaction with sulfur and phosphorus. Benefiting from structure functionalities and electronic control of a single-atom iron active center, the catalyst shows a remarkable performance with enhanced kinetics and activity for oxygen reduction in both alkaline and acid media. Moreover, the catalyst shows promise for substitution of expensive platinum to drive the cathodic oxygen reduction reaction in zinc-air batteries and hydrogen-air fuel cells.

Zinc-Induced Conformational Transitions in Human Islet Amyloid Polypeptide and Their Role in the Inhibition of Amyloidosis.

Type-2 diabetes mellitus (T2DM) is a disease hallmarked by improper homeostasis within the islets of Langerhans of the pancreas. The most critical species affected is insulin, which is produced by the ß-cells of the islets, but there are a number of other species copackaged and cosecreted within the insulin granules. This includes zinc, which exists in high (millimolar) concentrations within the ß-cells, and islet amyloid polypeptide (IAPP), which is an amyloid peptide thought to induce ß-cell apoptosis through self-association into toxic amyloid oligomers. Zinc is essential in the packaging of crystalline insulin within the vesicles but it can also bind and interact with IAPP. This implies a complex relationship between all three species and diabetes, particularly in the structure and function of toxic IAPP aggregates. Atypical (low or high) concentrations of zinc generally appear to correlate with increased hIAPP aggregation, whereas physiological zinc concentrations have an inhibitory effect. To better understand how zinc ions alter the monomer and oligomer structure of hIAPP in vitro, we employ a combination of ion mobility mass spectrometry and atomic force microscopy. We observe an increase in the extended ß-hairpin conformation of hIAPP when it is bound to zinc. With sufficiently low concentrations of zinc this could result in an association site for zinc-free hIAPP, promoting amyloid aggregation. At high zinc concentrations, we see the appearance of a secondary zinc association site whose coordination could account for the loss of inhibition at high zinc concentrations. Generally, it appears that zinc preferentially stabilizes the ß-hairpin conformation of hIAPP and the population of zinc-bound hIAPP in solution determines what effect this has on amyloid aggregation.

Hetero-oligomeric Amyloid Assembly and Mechanism: Prion Fragment PrP(106-126) Catalyzes the Islet Amyloid Polypeptide ß-Hairpin.

Protein aggregation is typically attributed to the association of homologous amino acid sequences between monomers of the same protein. Coaggregation of heterogeneous peptide species can occur, however, and is implicated in the proliferation of seemingly unrelated protein diseases in the body. The prion protein fragment (PrP106-126) and human islet amyloid polypeptide (hIAPP) serve as an interesting model of nonhomologous protein assembly as they coaggregate, despite a lack of sequence homology. We have applied ion-mobility mass spectrometry, atomic force microscopy, circular dichroism, and high-level molecular modeling to elucidate this important assembly process. We found that the prion fragment not only forms pervasive hetero-oligomeric aggregates with hIAPP but also promotes the transition of hIAPP into its amyloidogenic ß-hairpin conformation. Further, when PrP106-126 was combined with non-amyloidogenic rIAPP, the two formed nearly identical hetero-oligomers to those seen with hIAPP, despite rIAPP containing ß-sheet breaking proline substitutions. Additionally, while rIAPP does not natively form the amyloidogenic ß-hairpin structure, it did so in the presence of PrP106-126 and underwent a conformational transition to ß-sheet in solution. We also find that PrP106-126 forms hetero-oligomers with the IAPP8-20 fragment but not with the "aggregation hot spot" IAPP20-29 fragment. PrP106-126 apparently induces IAPP into a ß-hairpin structure within the PrP:IAPP heterodimer complex and then, through ligand exchange, catalytically creates the amyloidogenic ß-hairpin dimer of IAPP in significantly greater abundance than IAPP does on its own. This is a new mechanistic model that provides a critical foundation for the detailed study of hetero-oligomerization and prion-like proliferation in amyloid systems.

Modelling and Predicting Backstroke Start Performance Using Non-Linear and Linear Models.

Our aim was to compare non-linear and linear mathematical model responses for backstroke start performance prediction. Ten swimmers randomly completed eight 15 m backstroke starts with feet over the wedge, four with hands on the highest horizontal and four on the vertical handgrip. Swimmers were videotaped using a dual media camera set-up, with the starts being performed over an instrumented block with four force plates. Artificial neural networks were applied to predict 5 m start time using kinematic and kinetic variables and to determine the accuracy of the mean absolute percentage error. Artificial neural networks predicted start time more robustly than the linear model with respect to changing training to the validation dataset for the vertical handgrip (3.95 ± 1.67 vs. 5.92 ± 3.27%). Artificial neural networks obtained a smaller mean absolute percentage error than the linear model in the horizontal (0.43 ± 0.19 vs. 0.98 ± 0.19%) and vertical handgrip (0.45 ± 0.19 vs. 1.38 ± 0.30%) using all input data. The best artificial neural network validation revealed a smaller mean absolute error than the linear model for the horizontal (0.007 vs. 0.04 s) and vertical handgrip (0.01 vs. 0.03 s). Artificial neural networks should be used for backstroke 5 m start time prediction due to the quite small differences among the elite level performances.

Distal amyloid ß-protein fragments template amyloid assembly.

Amyloid formation is associated with devastating diseases such as Alzheimer's, Parkinson's and Type-2 diabetes. The large amyloid deposits found in patients suffering from these diseases have remained difficult to probe by structural means. Recent NMR models also predict heterotypic interactions from distinct peptide fragments but limited evidence of heterotypic packed sheets is observed in solution. Here we characterize two segments of the protein amyloid ß (Aß) known to form fibrils in Alzheimer's disease patients. We designed two variants of Aß(19-24) and Aß(27-32), IFAEDV (I6V) and NKGAIF (N6F) to lower the aggregation propensity of individual peptides while maintaining the similar interactions between the two segments in their native forms. We found that the variants do not form significant amyloid fibrils individually but a 1:1 mixture forms abundant fibrils. Using ion mobility-mass spectrometry (IM-MS), hetero-oligomers up to decamers were found in the mixture while the individual peptides formed primarily dimers and some tetramers consistent with a strong heterotypic interaction between the two segments. We showed by X-ray crystallography that I6V formed a Class 7 zipper with a weakly packed pair of ß-sheets and no segregated dry interface, while N6F formed a more stable Class 1 zipper. In a mixture of equimolar N6F:I6V, I6V forms a more stable zipper than in I6V alone while no N6F or hetero-typic zippers are observed. These data are consistent with a mechanism where N6F catalyzes assembly of I6V into a stable zipper and perhaps into stable, pure I6V fibrils that are observed in AFM measurements.

Glyphosate-based herbicides toxicity on life history parameters of zoophytophagous Podisus nigrispinus (Heteroptera: Pentatomidae).

The increase of agricultural areas with glyphosate-resistant (GR) crops, and use of this herbicide in Brazil, makes necessary to assess its impacts on non-target organisms. The objective was to evaluate the development, reproduction and life table parameters of Podisus nigrispinus (Heteroptera: Pentatomidae) reared on GR-soybean plants treated with glyphosate formulations (Zapp-Qi, Roundup-Transorb-R and Roundup-Original) at the recommended field dose (720g acid equivalent ha-1). Glyphosate formulations had no affect on nymph and adult weight of this predator. Fourth instar stage was shortest with Zapp Qi. Egg-adult period was similar between treatments (26 days) with a survival over 90%. Zapp-Qi and Roundup-Transorb-R (potassium-salt: K-salt) reduced the egg, posture and nymph number per female, and the longevity and oviposition periods of this predator. Podisus nigrispinus net reproductive rate was highest in GR-soybean plants treated with Roundup-Original (isopropylamine-salt: IPA-salt). However, the duration of one generation, intrinsic and finite increase rates, and time to duplicate the population, were similar between treatments. Glyphosate toxicity on P. nigrispinus depends of the glyphosate salt type. IPA-salt was least harmless to this predator. Formulations based on K-salt altered its reproductive parameters, however, the development and population dynamic were not affect. Therefore, these glyphosate formulations are compatible with the predator P. nigrispinus with GR-soybean crop.

Monitoring training load in beach volleyball players: a case study with an Olympic team

AIM: Describe and compare training load dynamics of two Olympic beach volleyball players. METHODS Two Olympic beach volleyball players participated in this study (specialist defender and blocker: both aged 34 years, holding 14 years of competitive experience, height: 1.74 m and 1.81 m, weight: 69 kg and 65 kg, respectively). Internal training load (ITL), total weekly training load (TWTL), monotony and strain were obtained through the session rating of perceived exertion (session-RPE) for three training mesocycles (10 weeks). Lower limb explosive power was assessed through the counter movement jump (CMJ). RESULTS: Mean ITL, TWTL, monotony and strain during the 10-week period were: 370 ± 156; 1997 ± 838; 2.7 ± 1.3; 5621 ± 1802 arbitrary units (Defender) and 414 ± 153; 2392 ± 892; 2.7 ± 1.1; 6894 ± 3747 (Blocker). Mean of CMJ height was 47.0 ± 1.3 and 40.3 ± 1.6 cm, for the defender and blocker, respectively. The defender player presented higher ITL in the second (effect size (ES) = 0.90; 92/5/3, likely) and in the third (ES = 0.91; 94/4/2, likely) mesocycles when compared to the first. Monotony raised from the first to the third mesocycle (ES = 2.91; 98/1/1, very likely). Blocker's ITL was higher in the third mesocycle than the first (ES = 1.42. 98/1/1, very likely) and the second (ES = 1.49; 98/1/1, likely) ones. CONCLUSION: ITL magnitude increased from the first to the third mesocycle, in both players.(AU)