北京永定河谷中新元古界雾迷山组叠层石生长控制因素探讨

北京永定河谷庄户洼剖面中新元古界雾迷山组产出大量叠层石。本文对其形态进行分析测量,获得叠层石优势生长方向的雷达图,结合雾迷山组时期古板块方位、波痕构造所指示古水流方向及当时的构造应力方向等信息进行分析,对叠层石形态生长控制因素进行综合探讨。分析表明,因雾迷山组形成时期华北板块位于赤道附近,永定河谷庄户洼剖面雾迷山组叠层石形态不受阳光控制,控制其形态的主要因素是古水流。另外,构造应力活跃所引起的古地震频发导致了软沉积物向深海滑塌也影响了叠层石的生长形态,硅质填充物在后期破坏了叠层石的形态。对叠层石形态生长控制因素进行分析探讨,可帮助理解叠层石形态生长机理和古环境,具有重要的地球生态学意义。

Variation of Bacteria Biomass and its Possible Controlling Factors in the East China Sea

Two surveys were performed for determining bacteria biomass (BB), temperature, salinity, chlorophyll a (chl-a) and nutrient concentrations at 11 stations with three sampling depths in the high-incidence regions of red tide in the East China Sea (ECS) in the spring of 2006. Temperature and salinity increased from nearshore to offshore region and from high latitude to low latitude in the two cruises of 2006. BB were between 0.3 5.2 mgC m-3 (about 2.1 mgC m-3 on average) and 0.2 6.0 mgC m-3 (about 2.7 mgC m-3 on average) respectively in the two cruises. BB in the surface layer decreased from the Changjiang River estuary to high sea and from low latitude to high latitude. The results showed that bacterial growth was regulated by temperature, primary production and inorganic nutrient concentrations depending on different hydrographic conditions. In the surface and middle layers where the primary production can supply enough organic substrate, temperature was the main factor to control bacteria biomass. BB showed a good correlation between the surface and middle layers in both cruises. The distribution of nutrients during both cruises showed a similar decreasing trend from nearshore region and high latitude to offshore region and low latitude. High BB values were mainly recorded from samples in the middle layer where chl-a concentrations were also high, indicating primary production being strongly correlated with temperature over the ECS shelf. In the offshore area, phosphate and silicate became limiting factors for phytoplankton growth with indirect influence on BB. Bacteria played an important role in nitrogen regeneration process turning organic nitrogen to inorganic forms such as NH4+. The increasing ratio of NH4+/DIN could be a proof of that.

Improved myocardial perfusion and cardiac function by controlled-release basic fibroblast growth factor using fibrin glue in a canine infarct model

Objective： Angiogenic therapy is emerging as a potential strategy for the treatment of ischemic heart disease but is limited by a relatively short half-life of growth factors. Fibrin glue （FG） provides a reservoir for controlledrelease of growth factors. The aim of this study was to evaluate the effects of basic flbroblast growth factor （bFGF） incorporating FG on angiogenesis and cardiac performance in a canine infarct model. Methods： Acute myocardial infarction was induced by ligation of the left anterior descending coronary artery （LAD）. Group Ⅰ （n=6） underwent ligation of LAD alone. In Group Ⅱ, transmural channels were created in the infarct area （n=6）. In Group Ⅲ, nontransmural channels were created to locate FG cylinders containing bFGF （n=6）. Eight weeks after operation, myocardial perfusion was assessed by single photon emission computed tomography, cardiac function by echocardi- ography, and vascular development by immunohistochemical staining. Results： Total vascular density and the number of large vessels （internal diameter ≥50 pro） were dramatically higher in Group Ⅲ than in Groups Ⅰ and Ⅱ at eight weeks. Only the controlled-release group exhibited an improvement in regional myocardial perfusion associated with lower defect score. Animals in Group Ⅲ presented improved cardiac regional systolic and diastolic functions as well as global systolic function in comparison with the other two groups. Conclusions： Enhanced and sustained angiogenic response can be achieved by controlled-release bFGF incorporating FG within transmyocardial laser channels, thus enabling improvement in myocardial perfusion and cardiac function.

Inhibitory effect of Sumu(Lignum Sappan) plus Fuzi(Radix Aconiti Lateralis Praeparata) on a lung carcinoma model

OBJECTIVE: To investigate the inhibitory effect of Sumu(Lignum Sappan) plus Fuzi(Radix Aconiti Lateralis Praeparata)(SF) on the growth and metastasis of Lewis lung carcinoma.METHODS: A lung carcinoma model was established by subcutaneously inoculating Lewis lung carcinoma cells into C57 BL/6 mice. The mice were randomly divided into four groups of 13 mice(control, low-dose, moderate-dose, and high-dose), and gavaged once-daily for 21 consecutive days. The rates of tumor inhibition, metastasis, and metastasis inhibition were observed. The differential expressions of s P-selectin and vascular endothelial growth factor C(VEGFC) were compared between the treatment groups and the control group.RESULTS: The tumor weights differed significantly between the treatment groups and the control group(P < 0.05). Administration of SF in the moderate-dosage and low-dose groups significantly inhibited the expression of s P-selectin and VEGFC(both P < 0.05), suggesting anti-tumor activity.CONCLUSION: SF can inhibit the growth and metastasis of Lewis lung carcinoma.

Flowering responses to light and temperature

Light and temperature signals are the most important environmental cues regulating plant growth and development. Plants have evolved various strategies to prepare for, and adapt to environmental changes. Plants integrate environmental cues with endogenous signals to regulate various physiological processes, including flowering time. There are at least five distinct pathways controlling flowering in the model plant Arabidopsis thaliana: the photoperiod pathway, the vernalization/thermosensory pathway, the autonomous floral initiation, the gibberellins pathway, and the age pathway. The photoperiod and temperature/vernalization pathways mainly perceive external signals from the environment, while the autonomous and age pathways transmit endogenous cues within plants. In many plant species, floral transition is precisely controlled by light signals(photoperiod) and temperature to optimize seed production in specific environments. The molecular mechanisms by which light and temperature control flowering responses have been revealed using forward and reverse genetic approaches. Here we focus on the recent advances in research on flowering responses to light and temperature.