仙鹤草多糖的提取及部分理化性质

以多糖提取率为指标,采用L9（3^4）正交实验设计对仙鹤草多糖的提取工艺条件进行优化,并采用脱蛋白与DE-52纤维素离子交换柱层析法对仙鹤草多糖进一步分离纯化．同时对多搪的性质进行分析鉴定。实验结果表明,仙鹤草多糖的最佳提取工艺为：浸提温度为80℃,浸提时间12h,料液比1：15．在此条件下仙鹤草多糖提取率为2．15％,浸提温度是影响得率的主要因素。纯化后的仙鹤草多糖组分HAPI、HAPII多糖含量分别为70．08％、78．80％。     

奇亚籽多糖的提取及其在凝固型酸奶中的应用

以新鲜奇亚籽为试材，采用水提醇沉法提取奇亚籽多糖，用苯酚-硫酸法对多糖含量进行测定，并通过单因素和正交实验确定多糖最佳提取方法。实验结果表明，奇亚籽多糖的最佳提取方法为：料液比为1∶30(g∶mL)、浸提时间为2.5 h、浸提温度70℃,此条件下的下奇亚籽多糖的提取率为3.19%。将不同浓度的奇亚籽多糖添加到酸奶中，以酸奶感官评分和单因素实验为基础，通过正交实验分析奇亚籽多糖对酸奶持水力的影响。结果表明：奇亚籽多糖可以显著提高酸奶持水力，并且酸奶的最佳工艺条件为蔗糖添加量为8%、菌种接种量为7%、奇亚籽多糖添加量为0.5%。通过以上工艺制得的奇亚籽酸奶口感更佳。     

药百合多糖的提取工艺研究

对药百合多糖的提取工艺进行了探索性研究,选取与比较了固液比、提取时间、提取温度3个因素对药百合粗多糖提取率的影响,并采用L9（3^3）正交设计法优化提取条件,确定了最佳的提取条件为：提取温度70℃、回液比1：15、提取时间4h。选择此条件提取药用百合粗多糖,提取率为1．25％。     

响应面法优化超声波辅助提取黑木耳多糖的工艺研究

黑木耳是我国重要的药食兼用真菌,采用超声波辅助提取黑木耳多糖的方法,改进了传统的浸提工艺。研究超声功率、超声时间、液料比及水浴浸提时间等因素对黑木耳多糖提取效果的影响,在单因素基础上,进行响应面分析实验,结果表明,超声波辅助提取黑木耳多糖的最佳工艺条件为：超声功率520W,超声时间13min,液料比132,水浴浸提时间3.1h,黑木耳多糖得率可达16.59%。     

竹叶叶绿素的提取及其性质的稳定性

为了找到提取竹叶中叶绿素的最佳工艺条件,考察竹叶叶绿素的稳定性,通过单因素实验确定浸提溶剂种类原料颗粒度、料液比、浸提温度、浸提时间的合适范围,再利用正交试验法进行工艺优化. 结果表明,用无水乙醇提取竹叶叶绿素的最佳工艺条件是:原料颗粒度10～20目、料液比1∶5、浸提温度70℃、浸提时间7 h,竹叶叶绿素对紫外光、常见氧化剂(如H2O2)、Fe3 均具有较强的耐受性,在温度70℃以下以及近中性或偏碱性介质环境中性质基本稳定,遇Cu2 、Zn2 离子分别生成蓝绿色絮状沉淀和灰绿色颗粒状沉淀.     

辽南山葡萄籽多酚提取工艺的初步研究

以山葡萄籽为实验材料，通过单因素法提取葡萄籽中的多酚。根据不同浸提剂在540nm处可见光吸收情况的测定，确定70％甲醇溶液为最佳浸提剂。通过单因素试验确定了提取剂浓度、提取时间、提取温度、料液比的适用范围，再利用正交试验法进行工艺优化。确定最佳工艺条件为：体积分数70％的甲醇，料液比1：20（m／v），70℃水浴，浸提20min。山葡萄籽中多酚的含量可达18．981mg／g。     

新疆重瓣榆叶梅花食用色素提取方法的比较研究

以新疆地产榆叶梅花作实验材料。从浸提剂种类、浸提温度、浸提时间、物料配比以及浸提次数进行了提取方法的比较研究。结果表明：以pH为1～2的无水乙醇作为浸提剂，按固比1：15投料，在45℃保温浸提2次，每次2h为最佳提取条件。     

白及有效成分的提取研究

指出了白及作为一种传统的中药材,药用价值高,用药广泛,化学成分复杂,药理活性多样,具有良好的开发价值,为实现对白及的高值化利用,要对白及多糖提取工艺加以优化。采用水提醇沉法对白及粗多糖的提取(提取温度、提取时间和料液比值)进行了工艺参数的优化,在最佳工艺条件下,即料液比为1∶40,提取温度为80℃,提取时间为4 h,提取一次,白及粗多糖的提取率可达36.53%;采用超声法对白及粗多糖的提取(料液比值、超声时间和提取温度)进行了工艺参数的优化,在最佳工艺条件下,即料液比为1∶40,提取温度为60℃,提取时间为50 min,提取一次,白及粗多糖的提取率可达42.15%;采用碱提法对白及粗多糖的提取(浸提液pH值、提取时间、料液比和提取温度)进行了工艺参数的优化,在最佳工艺条件下,即浸提液pH值为9,提取时间为2 h,料液比为1∶36,提取温度为70℃,提取一次,白及粗多糖的提取率可达39.60%。     

滨州市沾化冬枣核中活性多糖的提取

利用沾化冬枣核为试验材料,进行了冬枣核多糖的提取分离研究。通过单因素试验确定冬枣核中多糖的含量,进一步通过正交试验确定了多糖的较优提取条件。结果表明:各因素对枣核多糖提取效果的影响程度从高到低依次为浸提温度浸提时间料液比。综合考虑提取效果与生产成本,对提取条件进行优化,确定了适宜的提取条件:料液比1∶20、浸提温度90℃、浸提时间4h。以期为冬枣的综合加工利用、为从废弃植物材料中提取生物活性成分提供参考。     

乙醇提取银杏叶黄酮方法的研究

探讨了乙醇提取银杏叶黄酮的方法。试验结果表明：不同的乙醇浓度、浸提温度、浸提时间、浸提次数、固液比等对银杏叶黄酮提取效果均产生不同程度的影响，其中浓度和温度的影响达显著水平。研究认为银杏叶黄酮乙醇提取法的最佳条件为：用50倍（v／w）的90％乙醇溶液于70℃条件下提取2次，每次2h。     

Browsing Damage on Pine (Pinus sylvestris and P. contorta) by a migrating moose (Alces alces) Population in Winter: Relation to Habitat Composition and Road Barriers

In Scandinavia, moose (Alces alces L.) sometimes cause severe browsing damage to economically-important pine. Moose-vehicle accidents have spurred construction of fences along roads, and these may interfere with moose migration between summer and winter ranges, or the road alone may be a barrier. If this happens and moose build up along roads, landowners may suffer economically. Therefore, this study investigated whether roads, fences or other factors influence the use of young pine stands by moose. Eighty stands along roads in northern Sweden were evaluated in which individually-browsed branches were counted on 9972 pines. Moose browsing was not significantly related to birch (Betula pendula Roth, B. pubescens Ehrh.) density, nor did it differ between pines (Pinus contorta Douglas or P. sylvestris L.). However, increased pine density, site productivity and proximity to a highway were associated with increased browsing. Further large-scale studies are needed to understand moose habitat selection and the effects of roads.     

Effects of Root Freezing on the Physiology and Growth of Picea glauca,Picea mariana and Pinus banksiana Seedlings Under Different Soil Moisture Regimes

The root systems of 2-yr-old Picea glauca, Picea mariana and Pinus banksiana seedlings were submitted to various frost temperatures during an artificial frost to induce different levels of root damage. Frost-damaged and control seedlings were placed in a greenhouse under high and low soil moisture regimes. Seedling growth and physiology were evaluated periodically. Seedling survival was reduced when root damage reached levels of 60-80%. Root systems of all three species showed partial to total recovery by the end of the experiment. In general, root freezing damage caused reductions in seedling growth, with these reductions becoming less significant over time. Root damage had little to no effect on black spruce and jack pine seedling physiology, while white spruce CO 2 uptake decreased with increasing root damage. Shoot nitrogen content of all three species decreased slightly with increasing root damage.     

Decomposition and nutrient loss from prunings of different contour hedgerow species in tea plantations in the sloping highlands of Sri Lanka

Contour hedgerows of multipurpose tree species in the sloping tea lands of Sri Lanka are expected to reduce soil erosion and also add significant amounts of plant nutrients to the soil via periodic prunings. The objective of this experiment was to characterize the biomass decomposition pattern and quantify the amount of nutrients added through prunings of six tree species (Calliandra calothyrsus, Senna spectabilis, Euphatorium innulifolium, Flemingia congesta, Gliricidia sepium and Tithonia diversifolia) currently being used in hedgerows associated with tea. Withered leaf and stem prunings (50 g) were enclosed in 2-mm litter bags, placed at 5-cm depth and retrieved after one, three, six, nine and 12 weeks. Loss of initial dry weight, N, P and K was measured. Single exponential decay function adequately described both dry weight and nutrient loss. Tree species differed significantly in their rate of breakdown with decomposition constants (k) varying from 0.0299 to 0.2006 week⁻¹ for leaves and from 0.0225 to 0.0633 week⁻¹ for stems. Gliricidia showed the highest k for leaves with the rest in the following descending order: Senna > Tithonia ≥ Euphatorium > Calliandra > Flemingia. A similar pattern was observed for loss of all nutrients with Calliandra and Flemingia always having lower k values than the rest. Although N immobilization was not observed, immobilization of P and K was observed during the first week of incubation in some species, particularly in stem prunings. Annual biomass of prunings differed significantly between tree species in the following descending order: Calliandra > Senna > Flemingia > Tithonia > Gliricidia > Euphatorium. Calliandra added the greatest amount of nutrients annually to the soil with Euphatorium adding the least. Calliandra prunings provided the annual total K requirement and 49% of the N requirement of mature tea. However, none of the species provided more than 5% of the P requirement. It is concluded that among the tree species tested, Calliandra and Flemingia are the most suitable for contour hedgerows in tea plantations of this agroclimatic region because of their higher soil nutrient enrichment capacity and slower decomposition rates which would minimize leaching losses. This revised version was published online in June 2006 with corrections to the Cover Date.     

Growth of Phlebiopsis gigantea in wood of seven conifer species

Heterobasidion parviporum and Heterobasidion annosum are widely distributed root‐rot fungi that infect conifers throughout Europe. Infection of conifer stumps by spores of these pathogens can be controlled by treating fresh stumps with a competing non‐pathogenic fungus, Phlebiopsis gigantea. In this study, growth of three Latvian strains of P. gigantea and the biological control agent ‘Rotstop’ strain was evaluated in stem pieces of Norway spruce, Scots pine, lodgepole pine, Douglas‐fir, Weymouth pine, Siberian larch and Sitka spruce. The growth rates of one H. parviporum and one H. annosum isolate were also measured in the same stem pieces. The growth rate of P. gigantea varied greatly in wood of different conifer species. It was higher in the three pine species, lower in Norway spruce and lowest in Sitka spruce and Siberian larch, and in Douglas‐fir, this fungus did not grow. The largest area of wood occupied by P. gigantea was in lodgepole pine. Growth of Latvian isolates of P. gigantea in the wood of Pinus and Picea species was comparable to that of the Rotstop isolate. Consequently, stump treatment with local P. gigantea isolates should be recommended. However, our results suggest that Douglas‐fir stump treatment against Heterobasidion by P. gigantea may be ineffective and other stump treatment methods should be considered.     

Effects of Seed Weight and Seed Type on Early Seedling Growth of Pinus sylvestris under Harsh and Optimal Conditions

The effects of seed weight and seed type on seedling growth of Pinus sylvestris (L.) were studied by seeding individually weighed orchard and stand seed in different mixtures under harsh (direct seeding in field) and optimal (seeding in nursery) conditions. In the nursery experiment an increase in the seed weight from 3 to 7 mg increased the seedling height by 10-27% and total weight by 27-113%, and decreased the height/diameter ratio by 5-6% after 2 yrs. With elimination of seed weight effects, orchard seedlings were 2% taller than stand seedlings in year 2. Without elimination of seed weight effects, orchard seedlings were 7-13% taller. In the field experiment an increase in the seed weight from 3 to 7 mg increased seedling height by 18-65%, stem volume by 81-274% and the number of top-buds by 23-34% in year 5. After elimination of seed weight effects, orchard seedlings were 7-13% taller than stand seedlings and without elimination of seed weight effects 20-21% taller after 5 yrs. Even after elimination of both seed weight and genetic effects orchard seedlings were 3-9% larger than stand seedlings in the field experiment. In conclusion, the influence of seed weight and seed type on growth traits and slenderness is highly significant and the influence seems to be greater in harsh conditions.     

Stand Structure in Pine,Spruce and Deciduous Forests: A Comparison Between Finnish and Russian Karelia

This study investigated the stand structure in pine, spruce and deciduous forests in the border district of Finland and Russia. A total of 46 mature forest stands was selected as pairs, the members of each pair being as similar as possible with respect to their forest site type, age, moisture and topography. The stands were then compared between the two countries by means of basal areas and number of stems. The proportions of dominating tree species were 2-12% lower, and correspondingly the proportions of secondary tree species higher, in Russian forests. The density of the forest stock was also higher in each forest type in Russia. The forests in the two countries differed most radically in terms of the abundance of dead trees. The amount was two to four times higher in Russian deciduous and spruce forests, and in pine forests the difference was 10-fold. The stand structures indicated that Russian coniferous stands, in particular, were more heterogeneous than intensively managed pine and spruce stands in Finland.     

Growth and Terminal Bud Formation in Picea abies Seedlings Grown with Alternating Diurnal Temperature and Different Light Qualities

The root collar diameter and the height:diameter ratio are of particular importance in container-grown seedlings where a high density in the containers may produce spindly seedlings. Temperature regimes and light quality are known to affect plant growth. The aim of this study was to identify responses in Picea abies (L.) Karst. seedlings grown with light providing different red:far-red ratios and under temperature regimes with alternating day (DT) and night temperature (NT) from negative (DT < NT) to positive (DT > NT) difference (DIF) between DT and NT. Experiments were conducted in controlled environment chambers and in a daylight phytotron. Only limited thermoperiodic responses appeared in P . abies seedlings with respect to seedling height and dry weight accumulation. The formation of terminal buds, however, was clearly delayed in seedlings grown at negative DIF. The results indicate a requirement for day extension light that is high in far-red, to prevent terminal bud formation under natural short-day conditions. An extended study should be conducted to clarify the minimum level of light intensity and the optimal light quality needed to prevent terminal bud formation under natural short-day conditions.     

Potential to harness superior nutritional qualities of exotic baobabs if local adaptation can be conferred through grafting

Baobab leaves form an important part of the local diet in Sahel countries and elsewhere in Africa. Existing leaf nutritional data and agroforestry performance information are based solely on Adansonia digitata L., the baobab of continental Africa. The introduction potential of Adansonia species from the center of diversity in Madagascar and from Australia remains untapped. To assess this potential, the mineral contents and B₁ and B₂ vitamin levels of dried baobab leaves were determined for five-year old trees of A. digitata, A. gibbosa (A. Cunn.) Guymer ex D. Baum, A. rubrostipa Jum. & H. Perrier (syn. A. fony Baill.), A. perrieri Capuron and A. za Baill. grown in an introduction trial in Mali. Nutritional data were evaluated against survival and vigor to identify promising germplasm. Leaf vitamin and crude protein contents were highest in the Madagascar species, especially A. rubrostipa (B₁ 88 mg 100 g⁻¹, B₂ 187 mg 100 g⁻¹, protein 20.7% dry weight). However, the local species far outperformed the introductions in survival, tree height, basal diameter and resistance to termites. We suggest grafting as a way of harnessing the vigor of well-adapted local baobab varieties to the superior nutritional profiles of A. rubrostipa and others. Cross-species grafting tests in Adansonia were successful, thus creating new agroforestry possibilities with different scion/rootstock combinations.     

Modelling of adequate pretwist for obtaining straight timber

Abstract

Wood in general and wooden studs in particular are often distorted owing to uneven shrinkage during the drying process in the sawmill. Twist is often the most detrimental of all types of distortion, and it is caused by spiral grain in combination with variations in moisture content. For sawmills, the objective is to produce dried, straight boards, and one method of dealing with boards with excessive spiral grain is to sort them out and then dry them in a pretwisted position to obtain straight boards after drying. A model using the finite element (FE) method for the simulation of drying twist distortions was first calibrated against laboratory experiments in which boards were dried with and without restraints and pretwists. After the calibration, the FE results were compared with industrial test results for boards that were dried without restraints or with restraints with zero pretwist, i.e. straight restraints. The FE model used an elastic–ideally plastic material model to obtain permanent deformations. The calibration was to set the yield stresses so that there was a good match between FE results and results from the laboratory experiments. The comparison between the industrial test results and the FE results showed that the FE model is capable of realistic simulations of drying boards with and without restraints and presumably also pretwists.     

CAD与建筑设计的关系

本文分析了CAD在设计中引起的正面和负面影响,并进行了系统的阐述,从而使设计者在应用中能够保持客观的态度。