1000 resultados para Chrysanthemum species


Relevância:

60.00% 60.00%

Publicador:

Resumo:

本论文由四章组成,第一、二、三章为实验论文,分别报道了中药羌活、菊花、全缘叶绿绒蒿的化学成分的高效液相色谱(HPLC)和液相色谱-质谱(LC-MS)联用分析以及挥发油的气相色谱-质谱(GC-MS)联用分析。第四章概述了重要藏药材化学成分的研究进展。 第一章首先对28批不同产地的羌活药材进行了HPLC分析,建立了羌活的指纹图谱。结果表明,不同产地羌活的化学成分基本相似,但是各组分在含量上存在较大差异。其次,对羌活的主要化学组分包括紫花前胡苷、紫花前胡素、6'-O-反式阿魏酸紫花前胡苷、茴香酸对羟基苯乙酯、羌活醇和异欧前胡素进行了定量分析。此外,针对同一产地不同采集时间的羌活挥发油进行系统分析,结果表明它们的化学成分基本相似,主要含有a-蒎烯、b-蒎烯、柠檬烯和龙脑乙酸酯等,只是各组分含量有所变化,这说明采集药材时要注意采集时间。 第二章分别报道了不同产地不同品种菊花非挥发性成分的液相色谱-二极管阵列检测-串联质谱(LC-PDA-MSn)分析和挥发性成分的气相色谱-质谱(GC-MS)联用分析比较。首先通过液相色谱-质谱-串联质谱对各色谱峰进行定性分析,通过与标准品对照,以及UV和MSn提供的结构信息,结合文献报道共鉴定了11个化学成分,包括绿原酸和10个黄酮化合物,并比较了不同品种菊花的化学成分相同之处和不同之处。另外,对七种不同品种不同产地的菊花挥发性成分通过GC-MS分析表明其主要挥发性成分为单萜类、倍半萜类化合物,共有成分樟脑、龙脑和龙脑乙酸酯等,各成分在不同挥发油中的含量变化明显。 第三章为藏药全缘叶绿绒蒿不同部位挥发油成分的气相色谱-质谱(GC-MS)联用分析,比较其挥发油化学成分及其含量变化的异同点。研究结果表明,全缘叶绿绒蒿花精油的化学成分明显多于全草部位,且两者主要成分有较大的差别。 第四章综述了青藏高原重要藏药材化学成分的研究进展。分别对藏药的资源特色和110多种常用重要藏药材的化学成分的研究情况以及藏药未来发展思路进行了阐述,以期对相关的研究提供一些信息。 This dissertation consists of four parts. The first part reports studies on the fingerprint of Notopterygium incisum and N. forbesii by HPLC-PDA-MSn, and on the constitutents of essential oil by GC-MS. The second part elaborates the chemical constitutents of Chrysanthemum L. by LC-MS and GC-MS analysis. The third part reports the chemical compositions of the essential oil from the different parts of Meconopsis integrifolia. The fourth part reviews on the progress of the studies on the chemical constitutents in Tibetan medicines. The first chapter is about HPLC analysis of a traditional Chinese herbal medicine Qiang-huo (Notopterygium incisum and N. forbesii ). Firstly, based on analyzing and contrasting the relative retention time and relative paek area in chromatographic fingerprint, the HPLC chromatographic fingerprint of Notopterygium incisum was established, which can used as a scientific basement for the quality evalution of this herb. Secondly, quantitative analysis were performed on the main chemical constitutents of Notopterygium incisum and N. forbesii including nodakenin, nodakenetin, 6’-O-trans-feruloylnodakenin, p-hydroxypenethylanisate, notopterol and isoimperatorin. The results indicated that the contents were variable related to different growth regions. Lastly, the essential oil of Notopterygium incisum collected in different harvest times is analyzed by GC-MS. The second chapter is about HPLC-MS and GC-MS analysis of several species of Chrysanthemum L. Firstly, eleven compounds including chlorogenic acid and ten flavone compounds were identified in the methanol extract of Chrysanthemum morifolium Ramat. from different regions by HPLC-MS analysis. Secondly, the essential oil of seven different species of Chrysanthemum L.were extracted by steam distillation, and its compositions were isolated and identified by GC-MS. The main active constitutents such as camphor, borneol and bornyl acetate were detected, but the relative content varied notably. The third chapter is about GC-MS analysis of the essential oil from different parts of Meconopsis integrifolia. It indicated great difference of the chemical compositions of their oil in the flowers and residual overground part. The last chapter is a review of the research progress of the Tibetan medicines, which includes their features and their main chemical constitutents.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

While engaged in geoecological field work on Victoria Island, 277 new plants could be recorded for the vicinities of Holman, Cambridge Bay, Wellington Bay, Mt. Pelly, Richardson Islands, Hadley Bay, and Minto lnlet; 8 of them were new for Victoria Island, 6 for the western Canadian arctic archipelago.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This paper examines empirically the relative influence of the degree of endangerment of wildlife species and their stated likeability on individuals' allocation of funds for their conservation. To do this, it utilises data obtained from the IUCN Red List, and likeability and fund allocation data obtained from two serial surveys of a sample of the Australian public who were requested to assess 24 Australian wildlife species from three animal classes: mammals, birds and reptiles. Between the first and second survey, respondents were provided with extra information about the focal species. This information resulted in the dominance of endangerment as the major influence on the allocation of funding of respondents for the conservation of the focal wildlife species. Our results throw doubts on the proposition in the literature that the likeability of species is the dominant influence on willingness to pay for conservation of wildlife species. Furthermore, because the public's allocation of fund for conserving wildlife species seems to be more sensitive to information about the conservation status of species than to factors influencing their likeability, greater attention to providing accurate information about the former than the latter seems justified. Keywords: Conservation of wildlife species; Contingent valuation; Endangerment of species; Likeability of species; Willingness to pay

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Examines how society allocates support for species’ conservation when numbers involved are large and resources are limited. Rational behaviour suggests that species in urgent need of conservation will receive more support than those species that are common. However, we demonstrate that in the absence of balanced knowledge common species will receive support more than they would otherwise receive despite society placing high existence values on all species. Twenty four species, both common and endangered and some with a restricted distribution, are examined. We demonstrate that balanced information is vital in order to direct more support for species that are endangered than those that are not. Implications for conservation stemming from the findings are discussed.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Inclusions of sp-hybridised, trans-polyacetylene [trans-(CH)x] and poly(p-phenylene vinylene) (PPV) chains are revealed using resonant Raman scattering (RRS) investigation of amorphous hydrogenated carbon (a-C:H) films in the near IR – UV range. The RRS spectra of trans-(CH)x core Ag modes and the PPV CC-H phenylene mode are found to transform and disperse as the laser excitation energy ћωL is increased from near IR through visible to UV, whereas sp-bonded inclusions only become evident in UV. This is attributed to ћωL probing of trans-(CH)x chain inhomogeneity and the distribution of chains with varying conjugation length; for PPV to the resonant probing of phelynene ring disorder; and for sp segments, to ћωL probing of a local band gap of end-terminated polyynes. The IR spectra analysis confirmed the presence of sp, trans-(CH)x and PPV inclusions. The obtained RRS results for a-C:H denote differentiation between the core Ag trans-(CH)x modes and the PPV phenylene mode. Furthermore, it was found that at various laser excitation energies the changes in Raman spectra features for trans-(CH)x segments included in an amorphous carbon matrix are the same as in bulk trans-polyacetylene. The latter finding can be used to facilitate identification of trans-(CH)x in the spectra of complex carbonaceous materials.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Chronic wounds are a significant socioeconomic problem for governments worldwide. Approximately 15% of people who suffer from diabetes will experience a lower-limb ulcer at some stage of their lives, and 24% of these wounds will ultimately result in amputation of the lower limb. Hyperbaric Oxygen Therapy (HBOT) has been shown to aid the healing of chronic wounds; however, the causal reasons for the improved healing remain unclear and hence current HBOT protocols remain empirical. Here we develop a three-species mathematical model of wound healing that is used to simulate the application of hyperbaric oxygen therapy in the treatment of wounds. Based on our modelling, we predict that intermittent HBOT will assist chronic wound healing while normobaric oxygen is ineffective in treating such wounds. Furthermore, treatment should continue until healing is complete, and HBOT will not stimulate healing under all circumstances, leading us to conclude that finding the right protocol for an individual patient is crucial if HBOT is to be effective. We provide constraints that depend on the model parameters for the range of HBOT protocols that will stimulate healing. More specifically, we predict that patients with a poor arterial supply of oxygen, high consumption of oxygen by the wound tissue, chronically hypoxic wounds, and/or a dysfunctional endothelial cell response to oxygen are at risk of nonresponsiveness to HBOT. The work of this paper can, in some way, highlight which patients are most likely to respond well to HBOT (for example, those with a good arterial supply), and thus has the potential to assist in improving both the success rate and hence the costeffectiveness of this therapy.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

1. Species' distribution modelling relies on adequate data sets to build reliable statistical models with high predictive ability. However, the money spent collecting empirical data might be better spent on management. A less expensive source of species' distribution information is expert opinion. This study evaluates expert knowledge and its source. In particular, we determine whether models built on expert knowledge apply over multiple regions or only within the region where the knowledge was derived. 2. The case study focuses on the distribution of the brush-tailed rock-wallaby Petrogale penicillata in eastern Australia. We brought together from two biogeographically different regions substantial and well-designed field data and knowledge from nine experts. We used a novel elicitation tool within a geographical information system to systematically collect expert opinions. The tool utilized an indirect approach to elicitation, asking experts simpler questions about observable rather than abstract quantities, with measures in place to identify uncertainty and offer feedback. Bayesian analysis was used to combine field data and expert knowledge in each region to determine: (i) how expert opinion affected models based on field data and (ii) how similar expert-informed models were within regions and across regions. 3. The elicitation tool effectively captured the experts' opinions and their uncertainties. Experts were comfortable with the map-based elicitation approach used, especially with graphical feedback. Experts tended to predict lower values of species occurrence compared with field data. 4. Across experts, consensus on effect sizes occurred for several habitat variables. Expert opinion generally influenced predictions from field data. However, south-east Queensland and north-east New South Wales experts had different opinions on the influence of elevation and geology, with these differences attributable to geological differences between these regions. 5. Synthesis and applications. When formulated as priors in Bayesian analysis, expert opinion is useful for modifying or strengthening patterns exhibited by empirical data sets that are limited in size or scope. Nevertheless, the ability of an expert to extrapolate beyond their region of knowledge may be poor. Hence there is significant merit in obtaining information from local experts when compiling species' distribution models across several regions.