34 resultados para 1052
Resumo:
孔石莼(Ulva pertusa Kjellm)是一种大型经济海藻,除了可直接食用外在医药方面也有广泛的应用。在古代医书上便记载有多种药用活性,我国民间也流传用孔石莼治疗中暑、水肿和小便不利等病症。本论文比较全面地分析了孔石莼多糖和类脂等主要化学组合,探讨用红外和核磁光谱来解释多糖结构,并首次研究了孔石莼多糖的体外抗肿瘤的体内降血脂活性。为进一步开发孔石莼资源做了部分基础性的工作。通过对提取扎石莼多糖和类脂的方法研究,确定了两种主要组仇的提取方法,得到了多糖样品WPS、APS、DWPS、DAPS和类脂样品。用化学和仪器分析方法对多糖样品进行了水分、灰分、硫酸基含量、总糖含量、特性粘度、元素分析、单糖分析、氨基酸分析、红外和核磁光谱分析等。结果表明:用乙醇脱脂后的脱脂孔石莼水提物(DWPS)得率最高,含硫酸基量和总糖量最高,特性粘度最小;孔石莼水提物(WPS)得率和含硫酸基量次之;孔石莼碱提物(APS)因深解性不好未能按常规方法测定其总糖含量,且未检测出水解硫酸根。孔石莼多糖的单糖要有鼠李糖、葡萄糖、木糖、糖醛酸等,并检测到少量的甘露糖和阿拉伯糖。谷氨酸、天冬西氨酸是多糖样品蛋白质中的主要氨基酸,D-3-OH-半胱氨酸含量亦较高。IR谱图中出现了硫酸基的吸收峰:~H-NMR及~(13)C-NMR谱图中出现了鼠李糖和糖醛酸的特征峰。类脂样品中,非极性类脂与极性类脂的比例约为1:2;GC-MS 分析结果表明,不饱和脂质含量达61.37%,其中多不饱和脂类占44.17%,n-3系列高度不饱和脂类占39.90%。三个多糖样品WPS、DWPS、DAPS进行抗口腔上皮癌(KB)和肝癌(Bel)肿瘤细胞体外实验,结果表明在5μg/ml的剂量时三个样品抑制率均在10%以下,无明显活性表现。以烟酸肌醇为阳性对照药,蒸馏水为空白对照,对孔石莼水提多糖WPS进行了三个剂量的降血脂动物实验。实验结果表明:脂蛋白改善情况有明显的剂量依赖性;中高剂量组可显著降低胆固醇、甘油酸三脂,明显改善脂蛋白胆固醇的含量分布:高剂量样品组(500mg/kg·d~(-1))的药用活笥最高,与相同剂量的阳性对照药烟酸肌醇结果相比,药效理佳。并对孔石莼多糖血脂的机理进行了讨论。
Resumo:
通过对青藏高原东部玛多县境内高寒地区20个科、38个属、62种植物叶片的稳定性碳同位素的测定,来确定植物群落的光合型.结果表明,所测定的62种植物的稳定性碳同位素比值(δ13C)介于-28.6‰和-25.2‰之间,说明这62种植物均属于C3植物,没有C4植物或CAM植物.植物这种光合型的分布与该研究区的环境因素有密切关系,低温是该区没有C4植物分布的关键因素,同时光合型的分布也反映了植物对独特地理环境的适应.
Resumo:
在高寒草甸鼠害治理过程中, 因治理方式、强度以及环境的差异, 鼠类群落的变动表现出不同的特点。次生植被地区, 灭杀高原鼢鼠和高原鼠兔后, 经补播、封育、灭杀残存高原鼢鼠等综合治理, 5年内, 高原鼢鼠和高原鼠兔种群数量显著低于灭杀前(P < 0.05) , 根田鼠和甘肃鼠兔种群数量剧烈波动, 鼠类群落多样性、均匀度指数年间波动大, 群落不稳定; 仅使用药物灭杀高原鼢鼠和高原鼠兔, 3年后, 高原鼢鼠种群数量与灭杀前无显著差异(P > 0.05) , 鼠类群落多样性、均匀度指数在灭鼠当年下降, 以后各年间变动不显著。原生植被地区, 使用药物灭杀高原鼠兔, 高原鼢鼠种群数量上升, 围栏封育措施, 对高原鼠兔种群的增长有显著的抑制作用(P < 0.05) , 但对高原鼢鼠作用不显著(P > 0.05) ; 单一药物灭杀高原鼠兔, 鼠类群落多样性、均匀度指数无显著变化, 灭杀3年后, 高原鼠兔种群数量与灭杀前无显著差异(P> 0.05) , 高原鼢鼠显著增加(P < 0.05)。人工大量捕杀高原鼢鼠, 非围栏封育地区, 高原鼠兔种群显著增加(P < 0.05)。
Resumo:
The occurrence of Late Cretaceous mafic dykes and their entrained peridotite and granulite xenoliths as well as clinopyroxene xenocrysts in the Qingdao region provide us a precious opportunity to unveil the nature and characteristics of the Late Mesozoic lithospheric mantle and lower crust beneath the Jiaodong region, and the change of the magma sources. These studies are of important and significant for understanding the lithospheric evolution in the eastern North China Craton. There were two periods of magma activities in Late Mesozoic in Qingdao Laoshan region, one was around 107Ma in the Early Cretaceous and the other around 86Ma in the Late Cretaceous according to the whole rock K-Ar age determination. The Early Cretaceous mafic dykes and the Late Cretaceous mafic dyke (i.e. Pishikou mafic dike) have completely different geochemical characteristics. The Early Cretaceous mafic dykes are enriched in LILE, strongly depleted in HFSE (Nb, Ta, Zr, Hf) and characterized by the highly radiogenic Sr and Nd isotopic compositions. These geochemical features indicate that the Early Cretaceous mafic dykes were derived from an enriched lithospheric mantle. In contrast, the Late Cretaceous mafic dyke is enriched in LILE, without HFSE depletion (Nb, Ta, Zr, Hf) and has less radiogenic Nd and Sr isotopic compositions. These geochemical features indicate that the Late Cretaceous mafic dyke was derived from the asthenosphere modified by subducted pelagic sediment contamination. The intrusive age of the Late Cretaceous mafic dyke provides further information for the termination of the lithosphere thinning for the eastern North China Crtaon. Pishikou Late Cretaceous mafic dyke contains abundant peridotitic xenoliths, granulite xenoliths and clinopyroxene xenocrysts. The peridotitic xenoliths can be divided into two types: high Mg# peridotites and low Mg# peridotites, according to their textural and mineral features. The high-Mg# peridotites have high Fo (up to 92.2) olivines and high Cr# (up to 55) spinels. The clinopyroxenes in the high# peridotites are rich in Cr2O3 and poor in Al2O3. The low-Mg# peridotites are typified by low Mg# (Fo <90) in olivines and low Cr# (Cr# <0.14) in spinels. The clinopyroxenes in the low-Mg# peridotites are rich in Al2O3 and Na2O and poor in Cr2O3. These two type peridotites have similar equilibrated temperatures of 950C-1100C. The Clinopyroxenes in the high-Mg# peridotites generally have high and variable REE contents (REE = 5.6-84 ppm) and LREE-enriched chondrite-normalized patterns ((La/Yb)N>1). In contrast, the clinopyroxenes in the low-Mg# peridotites have low REE contents (REE = 12 ppm) and LREE-depleted patterns ((La/Yb)N<1). The textural, mineral and elemental features of the low-Mg# peridotites are similar to those of the low-Mg peridotites from the Junan, representing the newly-accreted lithospheric mantle. However, the mineralogical and petrological features of the high-Mg# peridotites are similar to those of the high-Mg# peridotites from the Junan region, representing samples from the old refractory lithospheric mantle that was strongly and multiply affected by melts of different origins Late Cretaceous mafic dike in the Qingdao region also contains two types of granulite xenoliths according to the mineral constituents: the pyroxene-rich granulites and the plagioclase-rich granulites. Equilibrated temperatures calculated from the cpx-opx geothermometers are in a range of 861C - 910C for the pyroxene-rich granulites and of 847C - 890C for the plagioclase-rich granulites. The equilibrated pressure for the plagioclase-rich granulites is in a range of 9.9-11.7 kbar. Combined with the results of the peridotitic xenoliths, a 40C temperature gap exists between the peridotite and the granulite. The petrological Moho was 33~36 km at depths, broadly consistent with the seismic Moho estimated from the geophysical data. This indicates that there was no obvious crust-mantle transition zone in the Qingdao region in the Late Mesozoic. Pishikou Late Cretaceous mafic dyke entrained lots of clinopyroxene xenocrysts which are characterized by the chemical zoning. According to the zoning features, two types of clinopyroxene xenoliths can be classified, the normal zoning and the revise zoning. The normally-zoned clinopyroxene xenocrysts have LREE-depleted REE patterns in the cores. In contrast, the revisely-zoned clinopyroxenes have LREE-enriched REE patterns in the cores. According to the rim and core compositions of xenocrysts, all the rims are balanced with the host magma. Meanwhile, the origins of the cores were complicated, in which the normally-zoned clinopyroxenes were derived form the lithospheric mantle and some of the reversely-zoned clinopyroxnes were originated from the lower crust. Other revisely-zoned clinopyroxenes had experienced complex geological evolution and need to be further investigated. According to the above results, a simplified lithospheric profile has been established beneath the Qingdao region and a constraint on the nature and characteristics of the lithospheric mantle and lower crust has been made.