样木解析法及其在材积表编制中的应用研究

提出了一种材积表编制样本资料收集的新方法———样木解析法。即在标准地中采用随机或机械抽样方法选取样木,进行树干解析,获得样木生长过程;通过建立树皮系数与树皮率回归模型,将样木解析后的各龄阶去皮直径和去皮材积转化为带皮直径和带皮材积,一株样木可获得龄阶数个编表样本。经四川农业大学实习林场楠木一元材积表、二元材积表编制实践,有减少编表样本收集工作量、消耗林木少的优点,且能达到精度要求,同时,也为珍稀树种材积表编制样本资料收集提供了新的方法。     

科技、管理与市场──谈我厂如何在买方市场中营造“卖方市场”

在中纤板供大于求,市场极度疲软的情况下,福州人造板厂坚持以开拓市场为出发点,转变营销观念,改变营销策略,加大销售管理力度;坚持以用户满意为着眼点,强化企业质量管理,开展内部质量承诺和质量技术攻关活动;坚持以科技进步为支撑点,对引进技术设备大胆改造创新,积极开展科学研究和新产品开发,最终达到在买方市场营造“卖方市场”目标,使企业的生产经营活动保持良好的运行环境。     

无卡轴旋切机变速进给模型与恒线速旋切运动轨迹模型的研究

详细分析了无卡轴旋切机的工作原理,推导了旋切过程中刀刃进给速度与圆木直径的数学模型,同时得出旋切时间的近似计算式。从中可知,旋切过程中刀刃进给速度必须按一定规律变化才能保证旋切机正常工作。建立了旋切机恒线速旋切的运动轨迹模型,推导出旋切机恒线速旋切时间的精确计算式,并在此基础上提出了旋切时间简便的近似计算式。这些研究结果均可用于指导设计和进行实际生产。     

Uleine and demethoxyaspidospermine from the bark of Plumeria lancifolia

The isolation of (+)-uleine (1) and (+)-demethoxyaspidospermine (2) from the bark of Plumeria lancifolia is reported along with (1)H- and (13)C-NMR data.     

柞蚕雄蛾油对大鼠辅助降血脂功能的影响研究

为研究柞蚕雄蛾油对小鼠血脂代谢的影响,进行了雄性Wistar大鼠高脂饲料与不同剂量柞蚕雄蛾油的喂养试验,每4天称体重一次,每4天测定小鼠肝系数及血清总胆固醇（TC）、甘油三酯（TG）、高密度脂蛋白胆固醇（HDL‐C）和低密度脂蛋白胆固醇（LDL‐C）一次。结果表明：3个剂量组TC、TG、LDL‐C含量与高脂模型组比较显著低于高脂模型组,而HDL‐C显著高于模型组,具有显著性差异（P＜0．05）。     

Characterization of protein fractions from Bt-transgenic and non-transgenic maize varieties using perfusion and monolithic RP-HPLC. Maize differentiation by multivariate analysis

Protein fractions from transgenic Bt and non-transgenic maize varieties, extracted by the Osborne solvent fraction procedure, were characterized for the first time by perfusion and monolithic RP-HPLC in very short analysis times. Albumins and globulins from different transgenic Bt maizes as well as from their non-transgenic isogenic varieties were eluted in four peaks using perfusion RP-HPLC, whereas prolamins and glutelins were separated in seven peaks. Monolithic RP-HPLC enabled the separation of maize proteins in a large number of peaks showing 6 and 10 main peaks for albumins and globulins, respectively. Prolamins migrated at retention times higher than 5 min as seven peaks, whereas glutelins were separated in three main peaks appearing at retention times higher than 6.0 min. Moreover, chromatograms of the whole protein extracts showed 8 and 11 components for perfusion and monolithic RP-HPLC, respectively. A comparison of the chromatograms of the whole protein extracts relative to transgenic and non-transgenic varieties evidenced quantitative differences on the percentages of area, mainly for peaks 2 and 3 by perfusion RP-HPLC and for peaks 3 and 7 by monolithic RP-HPLC. A discriminant analysis based on these proteic profiles was carried out to classify and predict transgenic Bt maize lines, achieving 100% correct classification using perfusion RP-HPLC.     

Correlation of selected constituents with the total antioxidant capacity of coffee beverages: influence of the brewing procedure

Relationships between volatile and nonvolatile compounds and the antioxidant capacity of coffee brews prepared from commercial conventional and torrefacto roasted coffees, employing commonly used doses and prepared by four brewing procedures (filter, plunger, mocha, and espresso machine) were assessed. Significant correlations between volatile Maillard reaction products and antioxidant capacity (measured by both 2,2-diphenyl-1-picrylhydrazyl radical and redox potential methods) were not observed. Highly positive correlations between browned compounds and caffeine with both antioxidant capacity parameters were reported. Principal component analysis allowed coffee brews separation according to coffee roasting processes (PC1) and brewing procedures (PC2), showing that in all cases coffee brews from torrefacto roasted coffee were more antioxidant that those extracted from conventional ones; also, coffee brews extracted by an espresso machine were more antioxidant than those extracted by mocha, plunger, and filter machines.     

Different sorption behaviors for wine polyphenols in contact with oak wood

The evolution of polyphenols of enological interest- monomeric anthocyanins, (+)-catechin, (-)-epicatechin, gallic acid, and trans-resveratrol-in the presence of oak wood was investigated in aging-model conditions. Disappearance kinetics showed that, except for gallic acid, all of the wine polyphenols tend to disappear from the model wine in presence of oak wood, to reach an equilibrium after 20 days of contact. At equilibrium, the higher disappearance rates were obtained for monomeric anthocyanins and trans-resveratrol with values of 20 and 50%, respectively. For monomeric anthocyanins, the rate of disappearance seemed to be independent of their nature. In order to evaluate the contribution of sorption to oak wood in the disappearance phenomena, sorption kinetics were determined for trans-resveratrol and malvidin-3-glucoside through the extraction and the quantification of the fraction sorbed to wood. These curves showed that the wood intake of trans-resveratrol and malvidin-3-glucoside followed a two-step behavior, with a higher rate during the first 2 days, likely due to a surface sorption mechanism, and then a slower rate to reach the equilibrium, which could be related to a diffusion mechanism. The comparison of disappeared and sorbed amounts at equilibrium showed that a minor part of the disappeared monomeric anthocyanins were sorbed by wood. In contrast, half of the concentration decrease of trans-resveratrol in wine finds its origin in a sorption mechanism by oak wood. Results in real wine show similar sorption kinetics.     

Multivariate analysis for the evaluation of fiber, sugars, and organic acids in commercial presentations of table olives

Table olives constitute an important part of the Mediterranean diet and the diet of many non-olive-producing countries. The aim of this work was to determine the fiber, sugar, and organic acid contents in Spanish commercial presentations of table olives and characterize them by means of a multivariate analysis. The selection of variables was carried out on the basis of a canonical analysis and their classification, according to processing styles and cultivars, through a linear discriminant analysis. Values of dietary fiber in table olives ranged from 2 to 5 g/100 g edible portion (e.p.). Some stuffing materials (almond, hot red pepper, and hazelnut) or the addition of capers produced a significant increase in the total dietary fiber in green olives. Glucose, fructose, and mannitol were usually found in the ranges of 0-55, 0-70, and 0-107 mg/100 g e.p., respectively. Succinic acid was detected only in green and directly brined olives (0-40 mg/100 g e.p.), while lactic and acetic acids were used within the ranges of 0-681 and 5-492.8 mg/100 g e.p., respectively. A multivariate analysis showed that fiber, mannitol, and succinic, lactic, and acetic acids can be used to discriminate between processing styles (95.5% correct assignations) and cultivars (61.20%). Current data can also be used in the evaluation of the dietary value of table olives.     

Content of Nutrient and Antinutrient in Edible Flowers of Wild Plants in Mexico

Nutrient and antinutritional/toxic factors present in some edible flowers consumed in Mexico were determined. The edible flowers were: Agave salmiana, Aloe vera, Arbutus xalapensis, Cucurbita pepo (cultivated), Erythrina americana, Erythrina caribaea, Euphorbia radians benth and Yucca filifera. The nutrient content in the flowers studied is similar to that of the edible leaves and flowers studied mainly in Africa. The moisture content of the flowers varied from 860 to 932 g kg⁻¹. Crude protein (CP) was between 113 to 275 g kg⁻¹ DM, crude fiber, 104 to 177 g kg⁻¹ DM and the nitrogen free extract, between 425 to 667 g kg⁻¹ DM. The highest chemical score (CS) was found in E. americana and A. salmiana; in five samples the limiting amino acid was lysine, and in three of them it was tryptophan. Trypsin inhibitors and hemaglutinnins had a very low concentration. Alkaloids were present in both the Erythrina species and the saponins in A. salmiana and Y. filifera. Cyanogenic glucosides were not found in the studied flowers. The traditional process of preparing these specific flowers before consumption is by cooking them and discarding the broth; in this way the toxic substances are diminished or eliminated. These edible flowers from wild plants consumed in local areas of the country play an important role in the diet of the people at least during the short time of the season where they are blooming.