Scientific physical core strength training of adolescent group / Treino científico de força do core de um grupo de adolescentes / Entrenamiento científico de fuerza del core de un grupo de adolescentes

ABSTRACT Introduction: A strong core can be more stable and improve the body posture of adolescents. This enables the organic integration and development of all parts of the body, as well as the coordination of the upper and lower limbs. Core strength training is conducive to improving its physical strength in the youth group. Objective: To study the influence of core strength on adolescents' motor skills and physical literacy. Methods: 40 teenagers were selected for group training. The experimental group performed core strength training, while the control group used traditional strength training. After the training period, the improvement of the physical fitness and motor skills of the two groups of volunteers was analyzed. Results: There were statistical differences between the two groups of young athletes in various technical and physical fitness indicators. Conclusion: Core strength training can improve the basic skills of young athletes, such as fast running, jumping and so on, but the effect of improving high physical fitness is not obvious. The experiment shows that a certain period of core strength training can improve their physical and motor skills. In future training for youth, core strength training should be advocated. Level of evidence II; Evidence from well-designed randomized controlled trials.

RESUMO Introdução: Um core mais forte pode ser mais estável e melhorar a postura corporal de adolescentes. Isso permite que haja uma integração orgânica e um desenvolvimento de todas as partes do corpo, assim como a coordenação dos membros superiores e inferiores. O treino da força do core leva à melhoria de sua força física no grupo de jovens. Objetivo: Estudar a influência da força do core nas habilidades motoras e na literacia física. Métodos: 40 adolescentes foram selecionados para treinamento em grupo. O grupo experimental passou por um treino da força do core, enquanto o grupo controle passou por treinos de força padrão. Depois do período de treino, a melhoria na aptidão física e nas habilidades motoras de ambos os grupos foi analisada. Resultados: Houve diferenças estatísticas entre os dois grupos de jovens atletas em diversos indicadores técnicos e de aptidão física. Conclusão: A força do core pode trazer melhorias às habilidades básicas de jovens atletas, tais como corrida em velocidade, saltos, e outras, mas seu efeito na melhoria da aptidão física de alto nível não é óbvio. O experimento mostrou que um certo período de treino de força do core pode aprimorar habilidades motoras e físicas. Recomenda-se a indicação do treino de força do core em treinamentos futuros para jovens. Nível de evidência II; Estudos terapêuticos - investigação de resultados de tratamento.

RESUMEN Introducción: Un core más fuerte puede ser más estable y auxiliar en la mejoría de la postura corporal de adolescentes. Esto permite que haya una integración orgánica y un desarrollo de todas las partes del cuerpo, así como la coordinación de los miembros superiores e inferiores. El entrenamiento de la fuerza del core proporciona la mejoría de su fuerza física en el grupo de jóvenes. Objetivo: Estudiar la influencia de la fuerza del core en las habilidades motoras y en la alfabetización física. Métodos: Fueron seleccionados 40 adolescentes para entrenamiento en grupo. El grupo experimental pasó por un entrenamiento de la fuerza del core, mientras que el grupo control pasó por entrenamientos de fuerza estándar. Después del periodo de entrenamiento, fue analizada la mejoría en la aptitud física y en las habilidades motoras de ambos grupos. Resultados: Hubo diferencias estadísticas entre los dos grupos de jóvenes atletas en diversos indicadores técnicos y de aptitud física. Conclusión: La fuerza del core puede proporcionar mejorías en las habilidades básicas de jóvenes atletas, tales como corrida en velocidad, saltos y otras, sin embargo, su efecto en el perfeccionamiento de la aptitud física de alto nivel no es obvio. El experimento mostró que un cierto periodo de entrenamiento de fuerza del core puede mejorar habilidades motoras y físicas. Se recomienda la indicación de entrenamiento de fuerza del core en preparaciones futuras para jóvenes. Nivel de evidencia II; Estudios terapéuticos - investigación de resultados de tratamiento.

Mechanical properties of cemented tailings backfill containing alkalized rice straw of various lengths.

The tailings and rice straw that are produced in large quantities each year in the mining and agricultural industries, respectively, have significant effects on the ecological environment. This study aimed to explore the mechanical properties of cemented tailings backfill (CTB) mixed with alkalized rice straw (ARS) of different lengths. A series of uniaxial compressive strength (UCS) and indirect tensile strength (ITS) tests were conducted on the CTB. The results indicated that as the length of the ARS increased from 3 to 15 mm, the UCS and ITS values initially increased and then decreased. The critical length of the ARS was 12 mm, for which the effect of strength increase was the most significant. From the overall analysis, the UCS of CTB samples with ARS (9 and 12 mm) demonstrated the better improvement (increased by 10.0 and 14.7%, respectively) at 28 d curing age, and the improvement effect of the CTB samples with ARS of other lengths was not ideal. The ITS of CTB samples with ARS increased (except for an ARS length of 3 mm) regardless of the curing age; the maximum increase was approximately 24.2% at 28 d. The integrity, residual strength, and toughness of CTB sample with the ARS (12 mm) were the largest after the UCS test. Scanning electron microscopy (SEM) tests indicated that the surface of the ARS was covered with cement hydration products, and the interior of the ARS was filled with cement tailings, which produced stronger adhesion between the ARS (12 mm) and CTB matrix; the ARS performed a bridging role and suppressed crack propagation, which effectively improving the mechanical properties of CTB. Significantly short ARS exhibited a lower adhesive force with the matrix, and significantly long ARS exhibited a lower filling rate. Thus, while improving the mechanical properties of CTB, ARS provides a new method for treating rice straw and decreasing its combustion pollution.

Comparative and functional genomics reveals genetic diversity and determinants of host specificity among reference strains and a large collection of Chinese isolates of the phytopathogen Xanthomonas campestris pv. campestris.

BACKGROUND: Xanthomonas campestris pathovar campestris (Xcc) is the causal agent of black rot disease of crucifers worldwide. The molecular genetic diversity and host specificity of Xcc are poorly understood. RESULTS: We constructed a microarray based on the complete genome sequence of Xcc strain 8004 and investigated the genetic diversity and host specificity of Xcc by array-based comparative genome hybridization analyses of 18 virulent strains. The results demonstrate that a genetic core comprising 3,405 of the 4,186 coding sequences (CDSs) spotted on the array are conserved and a flexible gene pool with 730 CDSs is absent/highly divergent (AHD). The results also revealed that 258 of the 304 proved/presumed pathogenicity genes are conserved and 46 are AHD. The conserved pathogenicity genes include mainly the genes involved in type I, II and III secretion systems, the quorum sensing system, extracellular enzymes and polysaccharide production, as well as many other proved pathogenicity genes, while the AHD CDSs contain the genes encoding type IV secretion system (T4SS) and type III-effectors. A Xcc T4SS-deletion mutant displayed the same virulence as wild type. Furthermore, three avirulence genes (avrXccC, avrXccE1 and avrBs1) were identified. avrXccC and avrXccE1 conferred avirulence on the hosts mustard cultivar Guangtou and Chinese cabbage cultivar Zhongbai-83, respectively, and avrBs1 conferred hypersensitive response on the nonhost pepper ECW10R. CONCLUSION: About 80% of the Xcc CDSs, including 258 proved/presumed pathogenicity genes, is conserved in different strains. Xcc T4SS is not involved in pathogenicity. An efficient strategy to identify avr genes determining host specificity from the AHD genes was developed.

Requirement of a mip-like gene for virulence in the phytopathogenic bacterium Xanthomonas campestris pv. campestris.

Macrophage infectivity potentiators (Mips) are FKBP domain-containing proteins reported as virulence factors in several human pathogens, such as members of genera Legionella, Salmonella and Chlamydia. The putative peptidylprolyl cis-trans isomerase (PPIase) encoded by XC2699 of the plant bacterial pathogen Xanthomonas campestris pv. campestris 8004 exhibits a 49% similarity at the amino-acid level to the Mip protein of Legionella pneumophila. This mip-like gene, XC2699, was overexpressed in Escherichia coli and the purified (His)6-tagged Mip-like protein encoded by XC2699 exhibited a PPIase activity specifically inhibited by FK-506. A mutation in the mip-like gene XC2699 led to significant reductions in virulence and replication capacity in the host plant Chinese radish (Raphanus sativus L. var. radiculus Pers.). Furthermore, the production of exopolysaccharide and the activity of extracellular proteases, virulence factors of X. campestris pv. campestris, were significantly decreased in the mip-like mutant. These results reveal that the mip-like gene is involved in the pathogenesis of X. campestris pv. campestris through an effect on the production of these virulence factors.