Practical Method of Form-finding of Semi-rigid Structures

Based on the discussion of the simulation for the cable prestress, the rigidity theory was used to identify the geometrical dimensions of semi-rigid structures in zero state. When the structural geometry in initial state is given, the geometrical dimension in zero state is determined by the initial prestress distribution. The contribution-matrix method is firstly applied to get the initial lack of fit. However, the influencing factor of initial lack of fit on the displacement of control point is linear superposition, that is, the structural response is linear, and it is irreconcilable with the geometry nonlinear of semi-rigid structure. In order to reduce the error of nonlinear structural response, the influencing factor in the contribution-matrix method is revised, and modified contribution-matrix method is put forward. Programs by ANSYS parameter design language APDL are worked out for the form-finding analysis of beam-string structure of a practical project. The numerical results show that the modified contribution-matrix method reduces the errors of the assumption of structural linear response. And it can be applied to the form-finding of semi-rigid structures with small stiffness.     

柳杉凋落物自毒作用研究

采用种子萌发法对浙江天目山柳杉Cryptomeria fortunei凋落物的自毒作用进行了研究,以探究这种凋落物的自毒作用对柳杉天然更新障碍的影响。结果表明,柳杉凋落物及其表层土壤浸提液在质量体积比为1 ∶ 10时,对柳杉种子萌发具有抑制作用。随着浸提液比例的降低（1 ∶ 100）,抑制作用减弱,甚至消失（1 ∶ 250）。自毒作用强度为未分解凋落物＞半分解凋落物＞表层土壤。而且未分解凋落物浸提液的化感作用强度随着样品含水率的增大而增强。通过高效液相色谱仪测定发现,柳杉凋落物和表层土壤中均含有酚酸类化感物质阿魏酸、肉桂酸和对羟基苯甲酸,而且未分解凋落物中的这3种物质的含量均是最高的。综合推测,这3种化感物质主要来自于未分解的柳杉凋落物。图2表4参22     

柳杉凋落物自毒作用研究

采用种子萌发法对浙江天目山柳杉Cryptomeria fortunei凋落物的自毒作用进行了研究,以探究这种凋落物的自毒作用对柳杉天然更新障碍的影响。结果表明,柳杉凋落物及其表层土壤浸提液在质量体积比为1 ∶ 10时,对柳杉种子萌发具有抑制作用。随着浸提液比例的降低（1 ∶ 100）,抑制作用减弱,甚至消失（1 ∶ 250）。自毒作用强度为未分解凋落物＞半分解凋落物＞表层土壤。而且未分解凋落物浸提液的化感作用强度随着样品含水率的增大而增强。通过高效液相色谱仪测定发现,柳杉凋落物和表层土壤中均含有酚酸类化感物质阿魏酸、肉桂酸和对羟基苯甲酸,而且未分解凋落物中的这3种物质的含量均是最高的。综合推测,这3种化感物质主要来自于未分解的柳杉凋落物。图2表4参22     

反季节白菜“夏阳50天”栽培技术

<正>"夏阳50天"(俗称抗热白菜、速生白菜)系从日本引进,是白菜家族中的珍贵品种,其主要特点是速生、抗热、抗湿、抗病性强,在35～37℃高温、高湿情况下能正常生长,适应性极为广泛,全     

Spatial Exploration of Multiple Cropping Efficiency in China Based on Time Series Remote Sensing Data and Econometric Model

This study explored spatial explicit multiple cropping efficiency(MCE) of China in 2005 by coupling time series remote sensing data with an econometric model-stochastic frontier analysis(SFA).We firstly extracted multiple cropping index(MCI) on the basis of the close relationship between crop phenologies and moderate-resolution imaging spectroradiometer(MODIS) enhanced vegetation index(EVI) value.Then,SFA model was employed to calculate MCE,by considering several indicators of meteorological conditions as inputs of multiple cropping systems and the extracted MCI was the output.The result showed that 46% of the cultivated land in China in 2005 was multiple cropped,including 39% doublecropped land and 7% triple-cropped land.Most of the multiple cropped land was distributed in the south of Great Wall.The total efficiency of multiple cropping in China was 87.61% in 2005.Southwestern China,Ganxin Region,the middle and lower reaches of Yangtze River and Huanghuaihai Plain were the four agricultural zones with the largest rooms for increasing MCI and improving MCE.Fragmental terrain,soil salinization,deficiency of water resources,and loss of labor force were the obstacles for MCE promotion in different zones.The method proposed in this paper is theoretically reliable for MCE extraction,whereas further studies are need to be done to investigate the most proper indicators of meteorological conditions as the inputs of multiple cropping systems.     

Purification and properties of a novel phenolic antioxidant from Radix astragali fermented by Aspergillus oryzae M29

The Chinese herb Radix astragalus (RA) has been widely used as a dietary supplement in Asia, and there are numerous reports on its bioactivities. However, there are no reports to date regarding the use of Aspergillus spp. in the culture medium of the RA plant for the production of phenolic antioxidants. In this study, utilizing the fungus Aspergillus to ferment the native RA has successfully resulted in a significant increase in the phenolic contents of RA, and the fermented RA also revealed much better antioxidant activity toward 2,2'-azinobis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radicals, hydroxyl radical, superoxide radical and peroxyl radical than those of unfermented RA. Among these phenolics, a potent novel antioxidant was isolated and identified as 3,4-di(4'-hydroxyphenyl) isobutyric acid with a molecular weight of 272, by ESI-MS (electrospray ionization mass), 1H NMR (nuclear magnetic resonance), 13C NMR, DEPT (distortionless enhancement by polarization transfer)-NMR, HMQC (heteronuclear multiple quantum coherence), and HMBC (heteronuclear multiple bond correlation) spectra. These data demonstrated that the solid-state bioprocessing strategy could be an innovative approach to enhance the antioxidant activity of RA.     

Pharmacokinetics and bioavailability of valnemulin in broiler chickens

Wang, R., Yuan, L.G., He, L.M., Zhu, L.X., Luo, X.Y., Zhang, C.Y., Yu, J.J., Fang, B.H., Liu, Y.H. Pharmacokinetics and bioavailability of valnemulin in broiler chickens. J. vet. Pharmacol. Therap. 34 , 247–251. The objective of this study was to investigate the pharmacokinetics and bioavailability of valnemulin in broiler chickens after intravenous (i.v.), intramuscular (i.m.) and oral administrations of 10 mg/kg body weight (bw). Plasma samples were analyzed by high‐performance liquid chromatography–tandem mass spectrometry (HPLC‐MS/MS). Pharmacokinetic characterization was performed by non‐compartmental analysis using WinNonlin program. After intravenous administration, distribution was wide with the volume of distribution based on terminal phase(V_z) of 4.27 ± 0.99 L /kg. Mean valnemulin t_1/2β(h), Cl_β(L /h /kg), V_ss (L /kg) and AUC_(0–∞)(μg·h /mL) values were 2.85, 0.99, 2.72 and 10.34, respectively. After intramuscular administration, valnemulin was rapidly absorbed with a C_max of 2.2 μg/mL achieved at 0.43 h (t_max), and the absolute bioavailability (F) was 88.81%; and for the oral route the same parameters were 0.66 ± 0.15 μg/mL, 1.54 ± 0.27 h and 74.42%. A multiple‐peak phenomenon was present after oral administration. The plasma profile of valnemulin exhibited a secondary peak during 2–6 h and a tertiary peak at 32 h. The favorable PK behavior, such as the wide distribution, slow elimination and acceptable bioavailability indicated that it is likely to be effective in chickens.     

Development of a capture ELISA to determine kinetics of soluble CD25 following in vitro and in vivo stimulation of duck peripheral blood monocytes

In humans and other mammals, the α-chain of interleukin-2 (IL-2) receptor (CD25) is induced and expressed on the cell surface after lymphocyte activation and is released from the membrane of activated cells as a smaller soluble form (sCD25). However, little is known about avian sCD25. In the present study, we developed an antigen capture enzyme-linked immunosorbent assay (AC-ELISA) to detect serum sCD25 in ducks, and we used flow cytometry (FCM) to analyze the frequency of CD25(+) cells in the peripheral blood of ducks infected with H9N2 or H5N1 avian influenza virus (AIV) or serotype II Riemerella anatipestifer (RA). Using the AC-ELISA, duck sCD25 molecules were detected in the supernatant and lysates of concanavalin A (Con A)-stimulated peripheral blood mononuclear cells (PBMC), and in the serum of ducks infected with H5N1 virus and RA. However, no sCD25 was detected in the serum of H9N2 AIV-infected ducks. FCM analysis revealed that CD25(+) cells were upregulated within the PBMC of RA-infected ducks throughout the experiment until death, while in the PBMC of H9N2- and H5N1 AIV-infected ducks, the frequency of CD25(+) cells increased in the early stage of infection and then returned to a lower level. Our findings confirm that the dynamics of sCD25 and CD25(+) cells are different in the peripheral blood of ducks infected with H9N2 virus, H5N1 virus, and RA.