孤立波与直立透空防波堤相互作用的解析研究

在一定条件下浅水波可能以孤立波形态与近岸防波堤发生相互作用。针对这一现象,应用特征函数展开法,推导了斜入射孤立波作用下有限厚度直立透空防波堤的反射与透射波浪场的解析积分解,并据此计算了作用于防波堤的孤立波波浪力以及孤立波反射与透射波面,相关结果具有一定的理论与实用价值。计算结果表明:孤立波入射角、海况条件、防波堤表面透空系数以及孤立波特征参数等因素变化对波浪作用均有一定影响。与相同浅水条件下的Airy微幅波理论结果相比,孤立波理论对波浪载荷与最大波面的预测值明显更大,反映了浅水波的非线性效应,同时说明在一定的浅水条件下采用孤立波模型将更为合理可靠。

甬优系列籼粳杂交稻产量及氮素吸收利用的差异

从24个甬优系列籼粳杂交稻品种(系)中,根据不同产量水平和氮素农学利用率筛选出具有代表性的3种类型(高产氮高效、高产氮中效、中产氮中效),系统比较各类型产量和氮素农学利用率,以探究高产氮高效型籼粳杂交稻产量和氮素吸收利用特征。结果表明,高产氮高效型产量显著高于高产氮中效型和中产氮中效型,分别高4.04%~4.38%和13.37%~13.41%,其高产原因在于群体颖花量大,能达到5.87×10^8~6.20×10^8 hm^-2。与高产氮中效型和中产氮中效型相比,高产氮高效型成穗率高,能保持在68.83%~70.05%;抽穗期叶面积指数高,且生育后期衰减平缓,成熟期叶面积指数在3.85以上;抽穗至成熟期干物质积累量大,达7.91~7.99 t hm^-2,全生育期干物质量可达21.15~21.46 t hm^-2。在氮素吸收利用方面,高产氮高效型总吸氮量显著高于高产氮中效型和中产氮中效型,分别高5.07%~5.14%和4.50%~5.96%;拔节至抽穗期和抽穗至成熟期氮素吸收速率表现为高产氮高效型>高产氮中效型>中产氮中效型,花后茎鞘氮素转运量、穗部氮素积累量和氮素收获指数也有相同表现;氮素回收利用率、农学利用率、生理利用率和偏生产力均以高产氮高效型最高;高产氮中效型除氮素回收利用率和百千克籽粒吸氮量外,其他各项氮素利用指标均高于中产氮中效型。

Automatically Smoothing the Spectroscopic Data by Cubic B-Spline Basis Functions

In the present paper,a new criterion is derived to obtain the optimum fitting curve while using Cubic B-spline basis functions to remove the statistical noise in the spectroscopic data.In this criterion,firstly,smoothed fitting curves using Cubic B-spline basis functions are selected with the increasing knot number.Then,the best fitting curves are selected according to the value of the minimum residual sum of squares(RSS)of two adjacent fitting curves.In the case of more than one best fitting curves,the authors use Reinsch's first condition to find a better one.The minimum residual sum of squares(RSS)of fitting curve with noisy data is not recommended as the criterion to determine the best fitting curve,because this value decreases to zero as the number of selected channels increases and the minimum value gives no smoothing effect.Compared with Reinsch's method,the derived criterion is simple and enables the smoothing conditions to be determined automatically without any initial input parameter.With the derived criterion,the satisfactory result was obtained for the experimental spectroscopic data to remove the statistical noise using Cubic B-spline basis functions.

Marsdeniae tenacissimae extract(MTE) suppresses cell proliferation by attenuating VEGF/VEGFR2 interactions and promotes apoptosis through regulating PKC pathway in human umbilical vein endothelial cells

Marsdeniae tenacissimae extract(MTE), commonly known as Xiao-Ai-Ping in China, is a traditional Chinese herb medicine capable of inhibiting proliferation and metastasis and boosting apoptosis in various cancer cells. However, little is known about the contribution of MTE towards tumor angiogenesis and the underlying mechanism. The present study aimed to evaluate the effects of MTE on the proliferation and apoptosis of human umbilical vein endothelial cells(HUVECs) and the molecular ism. 3-(4,5-dimethylthiazol-2-yl)-5(3-carboxymethoxyphenyl)-2-(4-sulfopheny)-2H-tetrazolium, inner salt(MTS) and PI-stained flow cytometry assays revealed that MTE dose-dependently reduced the proliferation of HUVECs by arresting cell cycle at S phase(P < 0.05). Annexin V-FITC/PI-stained flow cytometry confirmed that MTE(160 μL·m L-1) enhanced the apoptosis of HUVECs significantly(P < 0.001). Real-time quantitative RT-PCR and Western blot analyses showed an increase in Bax expression and a sharply decline in Bcl-2 expression; caspase-3 was activated simultaneously in a dose-dependent manner(P < 0.05). Further study observed the dose-dependent down-regulation of vascular endothelial growth factor(VEGF) receptor-2(VEGFR-2), P2Y6 receptor(P2Y6R), and chemokine(C-C motif) ligand 2(CCL-2), along with the activation of PKC δ and up-regulation of p53 in a dose-dependent manner in MTE-treated selected cells(P < 0.05). Collectively, the results from the present study suggested that MTE suppressed the proliferation by attenuating CCL-2-mediated VEGF/VEGFR2 interactions and promoted the apoptosis through PKCδ-induced p53-dependent mitochondrial pathway in HUVECs, supporting that MTE may be developed as a potent anti-cancer medicine.

Lunar potassium distribution:Results from Chang'E-1 gamma ray spectrometer

The global map of potassium is represented in this paper from Chang'E-1 (CE-1) Gamma-ray Spectrometer (CGRS) for its one-year mission.Assuming a linear relationship between net count rate and its abundance,the average potassium abundance of individual landing sites is used as ground-truth for the calibration to derive the global map of absolute concentration.Although CGRS spectra have a lower signal-to-noise ratio,the translated map still keeps relative variations.As calculated from Apollo,Lunar Prospector,and Kaguya,global potassium map from CGRS shows high concentrations on the lunar nearside and secondary concentrations located in the South Pole-Aitken (SPA) basin on the farside.The comparison with Lunar Prospector potassium map shows a good correlation,though abundances on the highlands of the farside are much lower than that of Lunar Prospector.Since the footprint of CGRS measurements is larger than the sampling radius of each landing site,the calibrated map shows a larger variation range of the scale than that of Lunar Prospector,which was derived using theoretical calculation;namely,the calibrated map has higher values in the areas with high concentration while having lower values for the areas with lower concentration.However,the derived potassium map is more consistent with the lunar sample data than that of Lunar Prospector.