Characteristics of pulmonary ventilation volumes under different exercise intensity with time / 军事医学

Objective To observe the changes of the pulmonary ventilation(VE)volume under different exercise intensities along with time,and to explore the best time for measuring VE under different intensities of exercise.Methods Sixty-one young mals were selected as subjects,who engaged in exercise of different intensities on the cycle ergometer(20, 40, 60, 80, 100, 120, 140, 160, and 180 W).The duration of exercise of each intensity was 6 minutes,the cardiopulmonary function was detected using a portable instrument,and real time monitoring of VE changes was enforced. Results (1)For exercise of intensity 20 W, VE initially increased fast with time, but after 1 min,it ceased to rise and remained stable.There was no significant difference at 1 min and afterwards(P>0.05).(2)The case was the same with exercise of the intensity 40 and 60 W.(3)For intensities of 80,100,120,140,and 160 W,VE became stable at 3 min. (4)For exercise of intensity 180 W,VE became stable at 4 min.Conclusion The time taken for VE to achieve stability under different intensities is different,which is positively correlated with the intensity of exercise.The greater the intensity of exercise,the longer it takes to achieve stability.

Effect of nano-SiO2 exposure on spatial learning and memory and LTP of hippocampal dentate gyrus in rats / 中国应用生理学杂志

<p><b>OBJECTIVE</b>To study the effect of nano-SiO2 on spatial learning and memory.</p><p><b>METHODS</b>Twenty-four male rats were randomly divided into 3 groups: control group (C group), low dose group (L group) and high dose group (H group). The rats were intragastrically administrated with nanometer particles at 25 and 100 mg/kg body weight every day for 4 weeks. After exposure, the ability of learning and memory of rats was tested by Morris water maze, and electrophysiological brain stereotactic method was used to test long-tear potentiation (LTP) in dentate gyrus (DG) of the rats.</p><p><b>RESULTS</b>The increase rate of body weight in H group was reduced significantly compared with C group ( P < 0.05). In the space exploration experiment of Morris water maze test, the escape latency of H group was longer than that of C group (P < 0.05). The rats of H group spent less time in finding the target quadrant (P < 0.05) . The rate of LP induction of H group was significantly lower than that of C group (P < 0.05). After high fre quency stimulation (HFS), The changes of amplitude of population spike (PS) of L group and H group were lower than those of C group significantly (P < 0.05, P < 0.01).</p><p><b>CONCLUSION</b>Nano-SiO₂may result in impairment of spatial learning and memory ability by reducing the rate of LTP induction and the increase of PS in hippocampus.</p>

Effects of retinol acid and triiodothyronine on alleviating the impairment of cognitive function by sleep deprivation / 中国应用生理学杂志

<p><b>OBJECTIVE</b>To explore the effects of retinol acid (RA) and triiodothyronine (T3) on alleviating the impairment of cognitive function by sleep deprivation (SD).</p><p><b>METHODS</b>Male Wistar rats were divided into 4 groups: control group (C group), sleep deprivation group (SD group), sleep deprivation + RA group (SD + RA group) and sleep deprivation + T3 group (SD + T3 group). Open field test (OFT) was used to observe the nervous behavior of the rats after SD and electrophysiological brain stereotactic method was used to test long-term potentiation (LTP) in dentate gyrus (DG) of the rats. Ng protein expression was determined by Western blot.</p><p><b>RESULTS</b>Compared with the SD group, the number of crossing in OFT, the changes of amplitude of population spike (PS) and the expression of Ng protein in hippocampus were higher significantly in the SD + RA and SD + T3 groups. All of these had not significant difference comparing with the C group.</p><p><b>CONCLUSION</b>RA and T3 may alleviate the restrain state of neural system after SD by augmenting the expression of Ng protein in hippocampus.</p>

Analysis of the electromyographic characteristics on shoulder fatigue caused by lifting load / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To analyze and evaluate the fatigue of shoulder skeletal muscle caused by different lifting loads with surface electromyography (sEMG).</p><p><b>METHODS</b>According to the loading standard of1 Repetition Maximum (1RM), ten male volunteers performed 3 tasks of upper limb flexion, i.e. 10%, 50% and 90%-1RM. During action process, the signals of Upper Trapezius (UT), Lower Trapezius (LT), Serratus Anterior (SA) and Anterior Deltoid (AD) were recorded by sEMG. The Mean Amplitude (MA) served as an index to evaluate the changes in skeletal muscle fatigue.</p><p><b>RESULTS</b>The scores of Borg were 15.6, 15.9 and 15.2 for 3 loads of 10%-1RM, 50%-1RM and 90%-1RM, respectively (P > 0.05). The mean amplitudes (MAs) of Upper Trapezius, Lower Trapezius, Anterior Deltoid and Serratus Anterior in shoulders increased obviously. Under the load intensity of 10%-1RM, the MAs of Upper Trapezius and Anterior Deltoid increased significantly (P < 0.05), which were 0.898 and 0.736, respectively. After the exhaustion, the contribution of mean amplitude in shoulder muscle did not change significantly (P > 0.05).</p><p><b>CONCLUSION</b>The low-load action for long time can induce easily the fatigue of upper trapezius and anterior deltoid.</p>

Marker-assisted selection and pyramiding for three blast resistance genes, Pi-d(t)1, Pi-b, Pi-ta2, in rice / 生物工程学报

G46B is a promising holding line used for three-lines breeding strategy in hybrid rice, but it is susceptible to blast disease caused by Pyricularia grisea. To improve its blast resistance, three rice varieties, Digu, BL-1, and Pi-4, with blast resistance genes, Pi-d(t), Pi-b, and Pi-ta2, respectively, were used to be crossed with G46B, and 15 plants with these three blast resistance genes, Pi-d(t)1, Pi-b, and Pi-ta2, were selected from their F2 and B1C1 populations via a marker-aided crossing procedure. Among them, four plants were heterozygotes in the three resistance genes, with the genotype of Pi-d(t)1 pi-d(t)/Pi-b pi-b/ Pi-ta2 pi-ta2; ten plants were heterozygotes in two of the three resistance genes, of which six with the genotype of Pi-d(t)1 Pi-d(t)1/Pi-b pi-b/Pi-ta2 pi-ta2, three with the genotype of Pi-d(t)1 pi-d(t)1/Pi-b pi-b/Pi-ta2 Pi-ta2, and one with the genotype of Pi-d(t)1pi-d(t)1/Pi-b Pi-b/Pi-ta2 pi-ta2; and only one plant was homozygote in two of the three resistance genes with the genotype of Pi-d(t)1 Pi-d(t)/Pi-b pi-b/Pi-ta2 Pi-ta2. These results demonstrate the capacity of maker-assisted selection (MAS) in gene pyramiding for rice blast resistance and its enhancement for the efficiency in rice resistance breeding.