天然香料在化妆品中的应用现状

：随着人们对天然、绿色、安全性化妆品的日益需求,天然香料在化妆品中也随之被广泛应用。天然香料主要分为植物性天然香料和动物性天然香料。本文主要介绍了天然香料的定义及其分类,天然香料在化妆品中的应用以及国内外可用于化妆品的天然香料工业发展等,并且根据天然香料在化妆品中应用存在的问题,提出几点建议。其中,在对天然香料的定义和分类中,除了明确天然香料的定义外,还根据其中含有的不同类型和功效的成分,分为天然香料中的芳香成分、药用成分、营养成分和其他成分。天然香料在化妆品中的应用,主要介绍目前市场上应用最广泛的动物类天然香料以及花类、叶类和果实类等植物性天然香料。此外,从三方面对天然香料在化妆品中的应用提出建议,主要为新资源综合利用及开发,改进技术并提高天然香料产量和质量,开发治疗性、保健性天然化妆品等。     

对害虫具自然控制能力的益害比指标模型研究

在害虫测报和防治工作中,经常要考虑天敌与害虫数量的比例问题,以决定是否需对害虫进行防治或决定相应的防治措施。如果采取防治措施过早,不能充分发挥天敌的自然控制作用,则会浪费人力物力;如采用化防还会加     

自然保护地自然教育资源分类与评价——以神农架国家公园为例

自然教育是生态文明建设的有力抓手及重要内容。自然保护地具有良好的自然资源禀赋,为自然教育实践提供活动场地及教育资源基础。在界定分析自然教育相关概念及内涵基础上,提出自然保护地自然教育资源分类方案,包括自然事物、场地设施、自然文化3项主类,9个亚类、48种基本类型;综合运用层次分析法和德尔菲法构建包括教育价值、资源质量、开发条件3层要素、10项指标的自然教育资源评价体系;以神农架国家公园为例进行自然教育资源分类及评价的实证分析。结果表明,构建的自然教育资源分类方案及评价体系具有科学性、普适性与可操作性,可在自然保护地自然教育资源的调查、分类与评价中推广,为自然保护地的自然教育开发利用提供科学参考。     

长江经济带自然资本使用量的空间效应及影响因素

厘清区域自然资本的使用情况及其空间效应和影响因素,对实现区域可持续发展具有重要的理论和现实意义.本研究以2008-2018年长江经济带112个地级市为研究区域,利用三维生态足迹模型、探索性空间数据分析、空间马尔科夫链和空间面板杜宾模型,分析区域总体和分地类自然资本流量和存量占用量的空间效应和影响因素.结果 表明:研究期...     

美国白蛾天敌研究进展

美国白蛾Hyphantria cunea(Drury)是国家林业和草原局的重点防控对象,也是我国重大外来林业检疫性有害生物.现阶段美国白蛾在我国的种群密度持续增加和扩散,缺乏有效天敌的控制应该是重要的原因之一.本文综述了国内、外美国白蛾的捕食性和寄生性天敌的种类.捕食性天敌主要包括昆虫、蜘蛛、两栖类和鸟类,整理出国外报道的捕食性天敌名录119种,国内捕食性天敌名录29种;寄生性天敌主要包括寄生蜂和寄生蝇类,整理出国外报道的寄生性天敌名录47种,国内寄生性天敌名录53种.本文回顾了我国在美国白蛾天敌利用方面取得的阶段成果,并针对将来天敌复合体的应用和原产地天敌的引进提出了展望.     

氮肥影响节肢动物天敌对褐飞虱种群的自然控制作用

氮肥在增加粮食产量的同时也可能对整个农田生态系统产生负面影响。稻田过量施用氮肥后,会提高水稻对害虫的敏感性、改变害虫与天敌之间的关系,最终影响到天敌对害虫的自然控制功能,导致害虫大发生。为了合理、公正地评价施用氮肥对稻田节肢动物天敌对害虫自然控制能力的影响,探索性地应用笼罩的方法在菲律宾国际水稻研究所试验农场稻田中研究了害虫天敌在不同氮肥施用水平(0,100 kg N/hm~2和200 kg N/hm~2)稻田中对褐飞虱的捕食能力及自然控制作用。试验结果表明,旱季田间的捕食性天敌对褐飞虱若虫的捕食能力和主要天敌对褐飞虱种群的自然控制能力均随稻田氮肥施用量的增加而减弱。在雨季,虽然天敌对褐飞虱种群的自然控制能力也随稻田氮肥施用量的增加而减弱,但捕食性天敌对褐飞虱若虫捕食能力的差异不明显。本研究表明,天敌对褐飞虱自然控制能力的减弱是稻田过量施用氮肥后褐飞虱种群猖獗的主要原因之一。     

IL-2- and IFN gamma-enhanced natural cytotoxic activity: analysis of the role of different lymphoid subsets and implications for activation routes

To elucidate the immunoregulatory mechanisms by which human recombinant interleukin 2 (r.IL-2) and human recombinant interferon (IFN)-gamma influence natural cytotoxic activity of human peripheral blood lymphocytes (PBL), experiments were performed in which we studied: the kinetics of augmentation of natural cytotoxic activity by IL-2 and IFN-gamma; the phenotypes of the natural cytotoxic precursor cells acted upon by IL-2 and IFN-gamma; the role of IL-2-induced IFN-gamma in the natural cytotoxic activity enhancing effects of IL-2 and (d) the surface phenotypes of the natural cytotoxic cells activated by IL-2 or IFN-gamma. Three phenotypical distinct precursor cells can be identified. The phenotypes of the precursor cells sensitive to r.IFN-gamma are T3-, Leu 7+or-, FcR-gamma+. The phenotypes of the precursor cells sensitive to r.IL-2 are T3-, Leu 7-, FcR-gamma+or-. It appears that during prolonged culture relatively more of the FcR-gamma- precursor cells acquire natural cytotoxic activity upon stimulation with r.IL-2. Antibodies to IFN-gamma, known to neutralize both recombinant and natural IFN-gamma, completely inhibited the IFN-gamma-induced augmentation of natural cytotoxic activity but only slightly affected the IL-2-mediated augmentation. This indicates that only part of the augmenting effect of r.IL-2 is mediated through IL-2-induced IFN-gamma. This implies that r.IL-2 augments natural cytotoxic activity predominantly through an IFN-gamma-independent pathway. The phenotype of the effector cells expressing natural cytotoxic activity after a 4-day culture period with IL-2 or IFN-gamma was analyzed by depletion experiments. Virtually all the cells that exerted the IFN-gamma-enhanced natural cytotoxic activity are FcR-gamma+, whereas a portion of the cells that exerted the IFN-gamma-enhanced natural cytotoxic activity are FCR-gamma-. Both natural killer cells and lymphokine-activated killer cells contribute to natural cytotoxic activity. The relative contributions of both activities to the natural cytotoxic activity augmented by IL-2, respectively, IFN-gamma, is discussed.     

戊二酰亚胺类天然产物生物合成研究进展

微生物天然产物是天然药物的重要组成部分,而天然产物的良好生物活性很大程度上取决于发挥药效的结构基团。这些特殊药效基团的生物合成,通常是利用小分子羧酸、氨基酸等结构简单的初级代谢产物,经过复杂的生物化学过程,最终合成结构复杂活性多样的天然产物。戊二酰亚胺类天然产物是一类重要的细菌来源天然产物,它们具有良好的生物活性,是潜在的先导化合物,部分化合物已被开发成分子探针。本文综述了近年来微生物来源的戊二酰亚胺类天然产物及其生物合成研究,包括Iso-Migrastatin、Lactimidomyin、Cycloheximide、Streptimidone、Gladiostatin、Sesbanimide等,对戊二酰亚胺类天然产物的生物合成研究,将有效促进通过基因组挖掘策略寻找新型戊二酰亚胺类天然产物。     

What Does It Take to Synergistically Combine Sub-Potent Natural Products into Drug-Level Potent Combinations?

There have been renewed interests in natural products as drug discovery sources. In particular, natural product combinations have been extensively studied, clinically tested, and widely used in traditional, folk and alternative medicines. But opinions about their therapeutic efficacies vary from placebo to synergistic effects. The important questions are whether synergistic effects can sufficiently elevate therapeutic potencies to drug levels, and by what mechanisms and at what odds such combinations can be assembled. We studied these questions by analyzing literature-reported cell-based potencies of 190 approved anticancer and antimicrobial drugs, 1378 anticancer and antimicrobial natural products, 99 natural product extracts, 124 synergistic natural product combinations, and 122 molecular interaction profiles of the 19 natural product combinations with collective potency enhanced to drug level or by >10-fold. Most of the evaluated natural products and combinations are sub-potent to drugs. Sub-potent natural products can be assembled into combinations of drug level potency at low probabilities by distinguished multi-target modes modulating primary targets, their regulators and effectors, and intracellular bioavailability of the active natural products.     

Attitudes to the importance of retaining natural teeth in an adult Swedish population

Objectives . To evaluate the attitudes to retaining natural teeth in an adult Swedish population, and to correlate the attitude to retaining natural teeth with some presumed influencing background factors. Design : Cross-sectional study using a newly developed questionnaire. Subjects : From the national census register of four municipalities in the southern part of the province of Halland, Sweden, with a total population of 126,878 adult (≥20 years) inhabitants, 4,200 persons were selected at random. The sample was randomised by age and sex, and 300 men and 300 women from the age groups 20, 30, 40, 50, 60, 70, and 80 years were included. Intervention and main outcome measures : The questionnaire aimed to evaluate the number of remaining natural teeth, the dental care habits, the self-estimated quality of natural teeth, and the attitude t o retaining natural teeth In the studied population, and also to evaluate the possible correlation between those factors, in particular, the attitude to retaining natural teeth versus the other factors. Results : It was found that the attitude to the importance of retaining natural teeth was strongly correlated with the number of remaining natural teeth, the dental care habits, and the self-estimated quality of natural teeth. Also sex had an influence on this attitude but not age. Conclusions : The attitude to the importance of retaining natural teeth in an adult Swedish population is correlated with the number of remaining natural teeth, the dental care habits, the self-estimated quality of natural teeth, and sex, but not with age.     

Natural products and combinatorial chemistry: back to the future

The introduction of high-throughput synthesis and combinatorial chemistry has precipitated a global decline in the screening of natural products by the pharmaceutical industry. Some companies terminated their natural products program, despite the unproven success of the new technologies. This was a premature decision, as natural products have a long history of providing important medicinal agents. Furthermore, they occupy a complementary region of chemical space compared with the typical synthetic compound library. For these reasons, the interest in natural products has been rekindled. Various approaches have evolved that combine the power of natural products and organic chemistry, ranging from the combinatorial total synthesis of analogues to the exploration of natural product scaffolds and the design of completely unnatural molecules that resemble natural products in their molecular characteristics.     

农药对捕食性天敌的影响研究进展

捕食性天敌在害虫的自然控制方面起着重要作用。当害虫大发生时,需使用化学农药来进行有效控害,但化学农药会对捕食性天敌的生存造成影响。因此,了解农药对捕食性天敌的影响有利于协调化学防治和生物防治的关系。大部分农药对捕食性天敌的生长发育和繁殖表现为抑制作用,但有的为促进作用。在农药的干扰下,多数捕食性天敌的信息识别能力会降低,少部分会通过提高雄虫接收性信息素的能力或增加雌虫性信息素的释放来诱导求偶行为、增加交配频率。有的杀虫剂会影响捕食性天敌的捕食行为及捕食功能,部分杀虫剂会直接使其捕食功能模型由Holling-Ⅱ型转变为Holling-Ⅰ型。在农药胁迫下,捕食性天敌会产生抗药性,其解毒酶活性升高、保护酶活性改变及靶标部位敏感性下降可能是抗药性产生的机理。农药对捕食性天敌的影响研究在协调害虫化学防治和生物防治中有着重要的理论和现实意义,可以有效地推进捕食性天敌在害虫综合治理中的应用。     

Cortical sensitivity to visual features in natural scenes

A central hypothesis concerning sensory processing is that the neuronal circuits are specifically adapted to represent natural stimuli efficiently. Here we show a novel effect in cortical coding of natural images. Using spike-triggered average or spike-triggered covariance analyses, we first identified the visual features selectively represented by each cortical neuron from its responses to natural images. We then measured the neuronal sensitivity to these features when they were present in either natural images or random stimuli. We found that in the responses of complex cells, but not of simple cells, the sensitivity was markedly higher for natural images than for random stimuli. Such elevated sensitivity leads to increased detectability of the visual features and thus an improved cortical representation of natural scenes. Interestingly, this effect is due not to the spatial power spectra of natural images, but to their phase regularities. These results point to a distinct visual-coding strategy that is mediated by contextual modulation of cortical responses tuned to the spatial-phase structure of natural scenes.     

The nature of natural: defining natural character for the New?Zealand context

New?Zealand has a long-standing statutory policy goal to preserve the natural character of the coastal environment and various freshwater environments and their margins. In the absence of an authoritative definition, it has not been possible to develop a method to measure natural character and its change, nor the outcomes of the long-standing national policy goal. Here we develop a definition of natural character that is relevant and useful in the New?Zealand environmental, cultural and legal/policy context. Literature-derived interpretations of natural character and equivalent concepts are evaluated as to their potential suitability for developing a biophysical definition of natural character. Using a set of carefully designed criteria a subset of interpretations are condensed into a definition of natural character. The application of this definition is qualified following consideration of the literature addressing human perception and experiences of natural character. Appropriate reference conditions and baselines for evaluating natural character in different contexts are discussed.     

How,and how much,natural cover loss increases species richness

Aim The species–area relationship has been applied in the conservation context to predict monotonic species richness declines as natural area is converted to human‐dominated land covers. However, some conversion of natural cover could introduce new habitat types and allow new open habitat species to occur. Moreover, decelerating richness–area relationships suggest that, as natural area is converted to human‐dominated covers, more species will be added to the rare habitat than are lost from the common one. Area effects and increased habitat diversity could each lead to a peaked relationship between species richness and the relative amount of natural area. The purpose of this study is to quantify the effect on avian species richness of conversion of natural area to human‐dominated land cover. Location Ontario, Canada. Methods We evaluated the responses of total avian richness, forest bird richness and open habitat bird richness to remaining natural area within 993 quadrats, each of 100 km². We quantified the amount of natural land cover and land‐cover heterogeneity using remote sensing data. We used structural equation modelling (SEM) to disentangle the relationships among avian richness, natural area and land‐cover heterogeneity. Results Spatial variation in avian richness was a peaked function of remaining natural area, such that losses of up to 44% of the natural area increased avian richness. This partly reflects increased variety of land cover; however, SEM suggests that much of the increase in richness is due to pure area effects. Richness of forest species declined by two species over this range of natural cover loss while open habitat bird richness increased by approximately 20 species. The effect of natural area on species richness is consistent with the sum of species–area curves for natural habitat species and human‐dominated habitat species. Main conclusions At least in northern temperate forests, almost half of the natural land cover can be converted to human‐dominated forms before avian richness declines. Conversion of < 50% of regional natural area to human‐dominated land cover can benefit open‐area species richness with relatively few losses of forest obligate species. However, with > 50% natural area conversion, species begin to drop out of regional assemblages.     

新疆天然与种植黑加仑果实的营养成分分析与比较

本文通过新疆种植黑加仑和天然黑加仑的脂肪油、八种微量元素、十七种氨基酸以及维生素C的含量进行测定比较,得出：天然黑加仑脂肪油含量为17.9%,种植黑加仑脂肪油含量为12.9%,其中,天然黑加仑脂肪油中,r－亚麻酸的含量为19.02%,而种植黑加仑中,其含量为10.20%,天然黑加仑中K,Na,Ca,Cu,Zn的含量比种植黑加仑含量高,但同时Fe,Mn,Mg元素的含量却比种植黑加仑含量低。种植黑加仑的维生素C含量为99.6mg/g,天然黑加仑的含量为108mg/g,天然黑加仑的氨基酸的总量为1.63%,种植黑加仑为1.55%。     

Compensation behaviour by insect herbivores and natural enemies: its influence on community structure

Insect herbivores feeding on low-quality plants often compensate by increasing their consumption of plant tissue. This usually results in a longer developmental time leading to a higher vulnerability to natural enemies. This has been termed the slow-growth, high-mortality hypothesis. To explore how compensation may shape the species composition of herbivore and natural enemy populations, we present a mathematical model of a tri-trophic system incorporating both the nutritional quality of plants and herbivores, and the compensatory ability of herbivores and their natural enemies. Using this model we predict the abundance of herbivores and natural enemies, and some characteristics of the composition of species of insect communities along a gradient of plant nutritional quality. Specifically, we make the following predictions: 1) In the absence of natural enemies, the abundance of the juvenile herbivores increases with plant quality, and only highly compensating herbivores persist at low plant nutritional quality. 2) If natural enemies are present, the abundance of the juvenile herbivores decreases with increasing plant quality due to more effective suppression by the natural enemies. Poorly compensating herbivores increase while their highly compensating counterparts decrease with lowered plant quality. 3) When the plants have low nutritional quality, natural enemies will only persist when either very highly compensating herbivores are present or if the natural enemy itself is highly compensating. 4) The abundance of adult herbivores in a community with natural enemies can either increase or decrease with increasing plant quality depending on the compensatory abilities of herbivores and natural enemies.     

具年龄结构的种群在破碎化生境中的空间分布模型

随着人类和其他生物赖以生存的环境破碎化程度的加剧,许多以前是连续分布的物种,目前不得不在破碎化生境(斑块)中求生存,所以,种群在破碎化生境(斑块)中分布问题的研究对生物保护和生境重建意义重大．本文运用Leslie矩阵和Markov链建立了一个具年龄结构的种群在破碎化生境中随时间动态变化的分布模型,讨论了种群在该生境中持续存在以及灭绝的条件．