[Effects of stand density on understory species diversity and soil physicochemical properties of Pinus massoniana plantation]. / æž—åˆ†å¯†åº¦å¯¹é©¬å°¾æ¾æž—æž—ä¸‹ç‰©ç§å¤šæ ·æ€§å’ŒåœŸå£¤ç†åŒ–æ€§è´¨çš„å½±å“.

We analyzed understory species diversity, soil physicochemical traits and their relationships in the 25-year-old non-commercial Pinus massoniana plantations with five different stand densities, i.e., 1057, 1136, 1231, 1383 and 1515 trees·hm-2, in Wenfeng Mountain, Xinjin District, Sichuan Province, China. The results showed that a total of 110 species were found, belonging to 57 families and 98 genera. With the increase of tree density, the understory species showed a succession pattern from positive to moderate to shady. Different densities had significant effects on the contents of total potassium and organic matter in the soils. With the increase ofdensity, the contents of organic matter and total potassium in understory vegetation first increased and then decreased. The trends of the relationship between both diversity and soil physiochemical characteristics and tree density were similar. Both of them increased with the increase of density, with the maximum value presented at the density of 1136 trees·hm-2. The concentrations of total phosphorus, available potassium, total potassium and total nitrogen was closely related to plant diversity index. The results suggested that the density at 1136 trees·hm-2 would be more beneficial to improve the stability of species diversity and soil fertility of P. massoniana non-commercial plantations in Wenfeng Mountain.

[Evaluation of right ventricular function of patients with intraoperative device closure of atrial septal defect by ultrasonic Doppler tissue imaging].

OBJECTIVE: To study the application of Doppler tissue imaging (TDI) in the assessment of right ventricular function of patients with intraoperative device closure of atrial septal defect (ASD). METHODS: A total of 48 ASD patients, 18 males and 30 females, were selected for intraoperative device closure. The mean age was 31 +/- 16 years old. Color Doppler echocardiographic instrument (Sonos 4500) was employed to perform the Doppler tissue imaging before and at 3-5 days after operation. The parameters included: (1) Time and peak speed of systolic motion of anterior tricuspid valve annulus (TDI-TS, TDI-PVS), early diastole motion time (TDI-TE) and late diastolic motion time (TDI-TA) and peak speed of early and late diastolic motion (TDI-PVE, TDI-PVA), interval between the early diastolic motion and late diastolic motion (TDI-TE-A); (2) Peak speed of systolic, early diastolic and late diastolic motions of the middle lateral and basic lateral walls of right ventricle. RESULTS: The TDI-PVS (0.16 +/- 0.05) m/s in post-operation was decreased than TDI-PVS (0.20 +/- 0.04) m/s in pre-operation and TDI-PVA (0.12 +/- 0.03) m/s in post-operation was decreased than TDI-PVA (0.16 +/- 0.02) m/s in pre-operation apparently (P < 0.01). The TDI-TS (231 +/- 36) msec in post-operation were shorter than TDI-TS (265 +/- 24) msec in pre-operation (P < 0.01). Peak spead of Systolic, early diastolic and late diastolic motions of middle lateral and basic lateral walls of right ventricle declined post-operatively (P < 0.01). CONCLUSION: TDI is an effective method to evaluate the function of right ventricle quantitatively in patients with intraoperative device closure of ASD.