The relationship between physical exercise and school adaptation of junior students: A chain mediating model.

Objective: This study explores the relationship between physical exercise and school adaptation of junior middle school students and constructs a chain intermediary model through the intermediary role of psychological resilience and sports learning motivation. Methods: Using the stratified cluster sampling method, 930 junior middle school students in Anhui Province were measured in group psychology by using the physical exercise rating scale, adolescent psychological resilience scale, physical learning motivation scale and school adaptation scale. The statistical software SPSS 23.0 and process plug-in were used for statistical processing, and the common method deviation test was carried out by Harman single-factor control method. Finally, the bootstrap sampling test method and process plug-in were used to test the significance of intermediary effect. Results: (1) The direct prediction effect of physical exercise on school adaptation is remarkable (t = 4.60, p < 0.01); (2) psychological resilience and sports learning motivation are the intermediary variables of the relationship between physical exercise and school adaptation; (3) psychological resilience and sports learning motivation play a chain mediation role in the relationship between physical exercise and school adaptation. The intermediary effect is composed of three indirect effects: physical exercise → psychological resilience → school adaptation (95% Cl: 0.004, 0.041), physical exercise → physical learning motivation → school adaptation (95% Cl:0.019, 0.065), physical exercise → psychological resilience → physical learning motivation → school adaptation (95% Cl:0.002, 0.021). Conclusions: Physical exercise can directly improve the school adaptation of junior middle school students, which can also affect junior middle school students' school adaptation indirectly through psychological resilience or sports learning motivation, and it can influence school adaptation through the chain mediation of psychological resilience and sports learning motivation.

[Alleviative effects of nitric oxide on the biological damage of spirulina platensis induced by enhanced ultraviolet-B].

Continuing depletion of the stratospheric ozone layer by atmospheric pollutants, in particular chlorofluorocarbons (CFCs), has resulted in an increasing incidence of solar UV-B (280-320 nm) at the Earth's surface. Enhanced UV-B radiation has been considered as important global environmental problem and results in important effects to mankind and the entire global ecosystem. Nitric oxide (NO) is not only a toxic molecule, one of reactive nitrogen species (RNS), but also an important redox-active signaling molecule. NO is really a double-edged sword, it can be either beneficial and activate defense responses in plants and animals or toxic, together with ROS. Besides those, NO can also act as a signal molecule and play very important roles in life of organisms. To study the effects of NO on the biological specific property of enhanced UV-B stressed Spirulina platensis, the chlorophyll-a, protein contents and biomass were investigated under enhanced UV-B radiation and its combination with different chemical treatment. The changes of chlorophyll-a, protein contents and biomass confirmed that 0.5 mmol/L sodium nitroprusside (SNP), a donor of nitric oxide (NO), could markedly alleviate the biological damage of cyanobacteria-Spirulina platensis 794 caused by enhanced ultraviolet-B. Further results proved that NO significantly increase the content of protein and proline. Meanwhile, the accumulation of reduced glutathione (GSH) in S. platensis cells were raised under normal growth condition. But exogenous NO could decrease the increasing of reduced glutathione (GSH) in enhanced UV-B stressed S. platensis cells. These results suggest that NO has protective effect and can strongly alleviate biological damage caused by UV-B stress in S. platensis 794 cells. For the first time, reported the effect of NO on the regulating ability of biological damage of S. platensis induced by enhanced UV-B. Therefore, further investigations will be necessary to inquire into the interaction and inter-correlation of signal molecules and the mechanism in cyanobacterium under enhanced UV-B stress.

The damage repair role of He-Ne laser on plants exposed to different intensities of ultraviolet-B radiation.

Light-grown broad bean (Vicia faba L.) seedlings were subjected to different intensities of UV-B radiation (0, 0.05, 0.15, 0.45, 0.90, 1.45 and 1.98 W m(-2)) for 7 h under photosynthetically active radiation (70 micromol m(-2) s(-1)) and then exposed to He-Ne laser (632.8 nm, 5.43 mW mm(-2)) radiation for 5 min or red light radiation for 4 h without ambient light radiation. When He-Ne laser radiated leaves were treated using lower intensity UV-B, the activities of superoxide dismutase (EC 1.15.1.1), ascorbate peroxidase (EC 1.11.1.11) and catalase (EC 1.11.1.6) improved significantly. Moreover, the UV-B-injured plants treated with laser light recovered faster from UV-B treatment because the concentration of malondialdehyde and the rate of electrolyte leakage from leaf disks reached control levels (no UV-B or laser treatment) early compared with those exposed only to ambient light or in dark conditions. Laser treatment, however, had no repair effect on seedling damage induced by higher UV-B radiation (1.45 and 1.98 W m(-2)), even with higher laser flux rates and longer laser treatment. In addition, the red light treatment had no repair effect on UV-B-induced damage. Meanwhile, the long-term physiological effect of He-Ne laser treatment on UV-B damaged plants was presented and evaluated. The results showed that the laser had a long-term positive physiological effect on the growth of UV-B-damaged plants. With the exception of the severe damage caused by higher UV-B radiation, a laser with the proper flux rate and treatment time can repair UV-B-induced damage and shorten the recovery time.

[Effects of the enhanced UV-B radiation on the body cell mitosis of the wheat].

The chromosomal mutation and mitosis of the wheat (Triticum aestivum, cv. 93-4736) were observed under the condition of the enhanced ultraviolet-B radiation. The results showed that the number of cells in mitosis of the UV-B treatments was 68.09% of the control, indicating that the UV-B treatment significantly inhibited division of root tip cells in wheat. Using t-test at P < or = 0.05, there was a significant difference between the control and the treatments. The enhanced UV-B significantly increased aberration frequency of chromosomes and cells (t = 9.51, n = 3, P < 0.05). Several types of chromosomal aberration such as lagging chromosomes of chromosomes bridge, fragments, nuclear aberration occurred in both of control and UV-B treatment. However, the frequency of lagging chromosome and fragments of chromosome was increased significantly by enhanced UV-B radiation (P < 0.05). Furthermore, the UV-B treatment caused several new types of chromosomal aberrations, such as three-bundle, four-bundle and six-bundle. In our opinion, these new types of chromosomal aberrations should be called 'partition-bundle division'. Under the condition of UV-B treatment, the amount of aberrations only accounted for 2.84% of the total during the interphase. In the period, nuclear abnormality appeared mainly in forms of micronucleolus and polycaryon. In the metaphase, there mainly exist fragment chromosome, which accounted for 26.67% of the total aberrations, being secondary to lagging chromosomes. The amount of chromosomal abnormality in the anaphase and telophase was the biggest, which included the types of bridge, lagging chromosomes, etc. Among the types, the lagging chromosomes were dominant, accounting for 32.84% of the total. In this study, what was especially emphasized was the UV-B induced abnormal mitosis that was first found. In the anaphase and telophase of the treated cells, chromosomes were divided into 3 bundles, 4 bundles, or 6 bundles, respectively accounting for 8.77%, 15.43%, and 8.02% of the total abnormal cells. Three-bundle division was nonsymmetrical. The number of chromosomes in each of the three bundles was not completely equal. Four-bundle division mainly symmetrized at direction of axis, the number of each of the two bundles on the same axis was basically the same, but was different from that on another axis. Four-bundle division was conducted in two patterns of division. With respect to the much more special six-bundle division, chromosomes were regularly divided into 3 groups, symmetrizing each other. As viewed from the number of chromosomes in each bundle, it was smaller than that in normal somatic cells. In the abnormal division of cells, cell plate or cell wall between the two divided bundles was not found, leading to 'multi-bundle bodies' occurrence by the end of cell division. Therefore, the abnormal division of the somatic cells should be called 'the multi-bundle division' or 'the partition bundle division'.

Association of interleukin-1B (IL-1B) gene polymorphisms with risk of gastric cancer in Chinese population.

The incidence of gastric cancer (GC) in China is among the highest in the world. In present work, 154 patients with GC and 166 healthy controls in population of north-western China were investigated to evaluate the genetic associations of IL-1B gene single nucleotide polymorphisms (SNP) and variable number tandem repeat (VNTR) polymorphisms of IL-1RN gene with increased risk of GC. The frequency of IL-1B+3954C/T was significantly higher in GC cases group (25.97%) than that in controls (4.82%) with odds ratio (OR)=6.93 (95% confidence interval [CI] 3.13-15.36); the frequencies of IL-1B-31C/T, IL-1B-31C/C and IL-1B-511C/T genotypes were also higher in GC cases group (51.95%, 23.38% and 50.65%) than those in controls (46.99%, 19.88% and 42.77%) with OR=1.48 (95% CI 0.88-2.49), OR=1.58 (95% CI 0.84-2.95) and OR=1.39 (95% CI 0.80-2.41), respectively. The results show that these SNPs of IL-1B gene are associated with significantly increased risk of GC. This is the first report that IL-1B+3954C/T heterozygote is associated with greatly increased risk of GC. The results of this study did not support the report that IL-1RN*2+ genotypes were associated with increased risk of GC in Chinese population.

[Effect of enhanced UV-B radiation on competition among several plant species].

The effect of enhanced UV-B radiation (280-315 nm, approximating a 15% ozone layer reduction) on competitive interaction between spring wheat (Triticum aestivum) and wild oat (Avena fatua) was examined in the field. The density-dependent mortality of both wheat and wild oat did not exhibit a significant difference between control and UV-B treatments. A relatively high degree of competitive stress enhanced the effect of UV-B stress on biomass reduction. Under UV-B enhancement, the relative competitive status of wheat in terms of total biomass and aboveground biomass increased, but decreased when based upon grain production. Shifts in competitive balance occurred with significant changes in total biomass, especially when plants grew at higher densities in monocultures and mixtures. There were different effects in direction and intensity of UV-B radiation on competition balance of the other three species pairs, but in general, the effect of UV-B was in favor of monocotyledonous. The results implied that total degree of competitive stress, especially interspecific competition, might be crucial to assess the effect of UV-B enhancement on agriculture ecosystem properly.