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To solve the problem of offshore oilfield development, based on the newly introduced pulsed neutron oxygen activation logging instrument, the application research of test design and interpretation method was carried out and applied to actual production. The structure, technical indicators and logging principles of pulsed neutron oxygen activation logging tools were introduced. The test design under different well conditions was studied, including general positive and negative injection, oil sleeve injection, single oil pipe configuration and multi-tubing configuration. A large amount of field test data was collected and analysed technically. A set of effective interpretation models was proposed. The corresponding interpretation software was developed. A set of test design methods and operating specifications for different well conditions were developed. Based on the conventional interpretation method, the peak selection, the double-tuber peak identification and the carbon dioxide f looding interpretation method were added. The results show that the test design and interpretation methods were applied well through a large number of field tests and production applications. Therefore, pulsed neutron oxygen activated injection profile logging technology is successfully applied in offshore oil fields
Topping, the critical cultural practice, is a kind of damage occurred tobacco shoot, which can obviously promote roots growth. Up to now, the mechanism regulating roots growth after topping is still unclear. In our previous works, miR171d was identified as a major topping responsive miRNA in tobacco roots, and its target gene was predicted to belong to the GRAS gene family. In the present study, NtGRAS-R1, a novel GRAS transcription regulator, was firstly cloned from tobacco roots. NtGRAS-R1 contained an open reading frame of 1527 bp encoding a 508-amino acids protein, and its molecular mass and isoelectric point was 56.199 KD and 5.24, respectively. GRAS proteins in tobacco can be grouped into nine subfamilies, including HAM, SCR, LAS, DLT, DELLA, SCL, LISCL, SHR and PAT1. NtGRAS-R1 is highly homologous with NtGRAS44 and belongs to HAM subfamily. The expression of NtGRAS-R1 can be detected in tobacco roots, leaves and stems, and its expression level was highest in tobacco roots. The analysis of transgenic tobacco showed that NtGRAS-R1 was involved in several biology processes, such as rooting, germination and root development, which will be helpful to explore the roles of NtGRAS-R1 in response to tobacco topping.
Background: Hypoxia plays a critical role in many cancers. Hypoxia inducible factor-1α (HIF-1α) is an important mediator of the hypoxia response. It regulates the expression of various chemokines involved in tumor growth, angiogenesis and metastasis but the associated pathway needs further investigation. Methods: The expression level of HIF-1α was determined in hepatocellular carcinoma (HCC) cells. The correlation of interleukin-8 (IL-8) and HIF-1α was assessed by knocking down HIF-1α. These cells were also used to assess its influence on HCC cell migration and invasion was checked. Pyrrolidinedithiocarbamate (PDTC), an inhibitor of NF-κB, was used to confirm the associated signaling pathway. Results: HIF-1α was significantly expressed in HCC cells and found to promote HCC cell migration and invasion in an IL-8-dependent manner. NF-κB was confirmed to be involved in the process. Conclusions: HIF-1α promotes HCC cell migration and invasion by modulating IL-8 via the NF-κB pathway.
Larix chinensis Beissn is an endangered plant found only in the Qinling Mountains, Shaanxi, northwestern China. It is densely distributed in the alpine and subalpine belt on their highest peak Taibai Mountain. Age structure studies along a montane altitudinal gradient would be helpful in understanding the limiting factors on the regeneration of natural forests. The forest was divided into three transects, i.e., lower limit (2900–3000 m), mid-altitude (3100–3200 m) and upper limit (3300–3400 m). The age structures differed across altitude classes. The age structure in the low altitude transect was closed to bell-shaped and characterized by the dominance of adult trees. A reverse-J shape age structure was found in the mid-altitude transect. Multi-modal age distribution was found in the high altitude transect, and was caused by lack of young seedlings and saplings. This suggests that different limiting factors play important roles in shaping the age structure and forest regeneration at different altitudes. In the low altitude, light availability was probably the most important limiting factor. In the mid-altitudinal transect, density dependent intraspecific competition between trees likely controlled regeneration of L. chinensis. We suggest that limiting climatic factors, e.g. temperature, play an important role in determining the age structure of L. chinensis populations in highaltitude areas.
Fritillaria unibracteata is a classic perennial alpine herb. In this study, we examined it's responses to shading (SH) and nitrogen addition (NA), as well as its correlation with internal C-N balance to detect how it adjusted to the changes of habitat conditions. Randomized block experiment was carried out in the field in Chuanbeimu Research Station in Songpan County, Sichuan Province, China (32°09′54″N, 103°38′36″E, altitude 3300 m a.s.l.). Two growing seasons after NA and SH, Fritillaria unibracteata's total plant biomass decreased significantly, with the proportion of biomass allocated to aboveground significantly increased. In addition, in this study, under both SH and NA treatments, Fritillaria unibracteata increased its biomass allocation to above-ground, which consisted with optimal partitioning theory. Moreover, Fritillaria unibracteata's biomass allocation was significantly correlated with its internal C-N status, regardless of nitrogen and light condition. We conclude that Fritillaria unibracteata optimizes its biomass allocation between root and shoot by adjusting its internal C-N balance, which would not be changed by the specialized resource storage organ-bulb.
In this study, glucose, inositol, glycerol, and sorbitol have been chosen as chemical modifiers to enhance laccase stability. The regularity of laccase activity variations was studied at different temperatures. Low concentrations of four polyhydroxyl compounds can improve the thermal stability of laccase at the whole temperature gradient (20~60ºC). The effect of glycerol is best in the all additives, and the relative enzyme activity of laccase increased 1.35 times by glycerol, in the concentration of 0.6 mol/L. The conformation of modified laccase is characterized by UV, fluorescence and circular dichroism. The result shows that the polyhydroxy compounds can change the conformation of laccase by increasing the hydrogen bonds between the laccase molecules and prevent the adverse change due to the increase of temperature in the secondary structure of laccase. Therefore, low concentrations of polyhydroxy compounds could be served as an additive to improve the thermal stability of the laccase.
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