食品科学与工程专业导论课程的构建与实践

通过开设专业导论课,探索大学新生中普遍存在的学习动力不足和学习适应困难问题的解决途径。分析了专业导论课的现状和开设课程的目的、意义,构建了食品专业导论课的课程体系,并对教师选择、教学方式、教学重点、重点内容剖析方法、课程定位、教材建设等教学实践中的关键问题作了分析总结,提出了18个字"是什么、学什么、为什么、怎么样、怎样学、干什么"(关键是9个字"学什么,为什么,怎样学")教学的基本思路。     

Effects of strategic helminthosis control on age at first lambing and lambing interval of communally grazed Menz ewes in Ethiopia

A three-year longitudinal study was conducted to evaluate effects of strategic anthelmintic treatment regimes on age at first lambing (AFL), weight at first lambing (WFL) and lambing interval (LI) of 356 communally grazed ewes and 675 lambs owned by 10 smallholder farmers in the central highlands of Ethiopia. The ewes were stratified by weight and randomly allocated to three treatment groups as untreated control (TG1), twice-dosed per year (TG2) for both nematodes and trematodes in mid-January and mid-June and four-time-dosed per year (TG3) in June for nematodes, in August–September for nematodes and adult Fasciola, in November–December and January–February for immature flukes. The fixed effect of anthelmintic treatments, parity, season and year of lambing on AFL and LI was evaluated. Mean ± standard error (SE) of lambing interval was 292 ± 3 days. Both anthelmintic treatments (TG2 and TG3) shortened (P < 0.01) LI by about 23 days compared to non-treated ewes (TG1). Season and year of lambing had a significant (P < 0.001) effect on LI. Mean ± SE of AFL and WFL was 598 ± 10 days and 17.2 ± 1.37 kg, respectively. Anthelmintic treatments and parity of dam of the ewe lamb did not affect AFL (P > 0.05). Birth and lambing seasons of the ewe lamb had significant (P < 0.05) effect on AFL. On the other hand, lambing season of the ewe had significant (P < 0.05) effect on WFL. Ewe lambs born in the long rains lambed more than 50 days earlier than the ewe lambs born in short rainy and dry seasons. Lambing occurred year-round with two peaks in August–September and December–January, each 5 months after the two rainy seasons. Anthelmintic treatment at the beginning of the two rainy seasons should improve reproductive performance of Menz ewe lambs in similar agro-ecology in the central highlands of Ethiopia.     

Foliar absorption — penetration of the cuticular membrane and nutrient uptake by isolated leaf cells

Summary Foliar absorption consists of penetration of a cuticular membrane and uptake by living cells within the leaf. A detailed analysis of nutrient absorption by these two systems has revealed that ionic penetration of the cuticular membrane is by diffusion, and that the coupling between active transport and metabolism is at the cellular level. Urea penetrates the cuticular membrane and is absorbed by leaf cells much more rapidly than are nutrient ions. Furthermore, urea facilitates penetration and absorption of other materials simultaneously applied. Penetration of nutrient ions through cuticular membranes has been localized by microautoradiography as occurring around stomatal pores and along periclinal cell walls. Chelation of metals such as iron, manganese and zinc reduces the rate of foliar absorption, but increases the translocation of the absorbed nutrient. At the cellular level the nutrient ion is absorbed and the ligand is excluded.

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Zusammenfassung Blattabsorption erfolgt durch Eindringen in Kutikularschichten der Membran und durch Aufnahme durch die lebenden Zellen innerhalb des Blattes. Eine detaillierte Analyse der N?hrstoffabsorption nach diesen beiden Systemen zeigte, da? die Ionen-Aufnahme über die Kutikularmembran durch Diffusion und da? die Koppelung des aktiven Transports mit dem Stoffwechsel im Zellbereich erfolgt. Harnstoff dringt durch die Kutikularmembran ein und wird viel schneller als N?hrstoff-Ionen durch die Blattzellen absorbiert. Weiterhin erleichtert Harnstoff das Eindringen und die Absorption anderer, gleichzeitig applizierter Substanzen. Die Fixierung der Eindringungsstelle von N?hrstoff-Ionen in Kutikularmembrane wurde durch Mikroautoradiographie ermittelt. Das Eindringen erfolgt um die Stomata-?ffnungen und entlang der periklinalen Zellw?nde. Metallgelate von Eisen, Mangan und Zink mindern die Zellabsorption, vermehren aber die Translokation der absorbierten N?hrstoffe. Im Bereich der Zellen werden N?hrstoff-Ionen absorbiert, aber Verbindungen ausgeschlossen.

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Résumé L'absorption foliaire consiste en une pénétration à travers la membrane cuticulaire, et l'assimilation par les cellules vivantes à l'intérieur de la feuille. Une analyse détaillée de l'absorption des éléments nutritifs par ces deux systèmes a révélé que la pénétration des ions à travers la membrane cuticulaire se fait par diffusion, et que le couplage entre le transport actif et le métabolisme se fait au niveau cellulaire. L'urée pénètre à travers la membrane cuticulaire et est absorbée par les cellules de la feuille beaucoup plus rapidement que ne le sont les ions nutritifs. D'autre part l'urée facilite la pénétration et l'absorption d'autres substances appliquées simultanément. La pénétration des ions nutritifs à travers la membrane cuticulaire a été localisée par microautoradiographie comme se faisant autour des pores stomatiques, et le long des parois des cellules périclinales. La chélation de métaux tels que fer, manganèse, zinc, réduit la vitesse d'absorption foliaire mais augmente la vitesse de transport de l'ion nutritif absorbé. Au niveau de la cellule, l'ion nutritif est absorbé, et le complexant est exclu.

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Report No. COO-888-51 in cooperation with the Division of Biology and Medicine of the United States Atomic Energy Commission, Contract AT (11-1)-888. Journal Article No. 3692 of the Michigan Agricultural Experiment Station.     

Community-based alternative breeding plans for indigenous sheep breeds in four agro-ecological zones of Ethiopia

Based on the results of participatory approaches to define traits in the breeding objectives, four scenarios of ram selection and ram use were compared via deterministic modelling of breeding plans for community-based sheep breeding programmes in four diverse agro-ecological regions of Ethiopia. The regions (and production systems) were Afar (pastoral/agro-pastoral), Bonga and Horro (both mixed crop-livestock) and Menz (sheep-barley). The schemes or scenarios differed in terms of selection intensity and duration of ram use. The predicted genetic gains per year in yearling weight (kilograms) were comparable across the schemes but differed among the breeds and ranged from 0.399 to 0.440 in Afar, 0.813 to 0.894 in Bonga, 0.850 to 0.940 in Horro, and 0.616 to 0.699 in Menz. The genetic gains per year in number of lambs born per ewe bred ranged from 0.009 to 0.010 in both Bonga and Horro. The predicted genetic gain in the proportion of lambs weaned per ewe joined was nearly comparable in all breeds ranging from 0.008 to 0.011. The genetic gain per year in milk yield of Afar breed was in the order of 0.018 to 0.020 kg, while the genetic gain per generation for greasy fleece weight (kg) ranged from 0.016 to 0.024 in Menz. Generally, strong selection and shorter duration of ram use for breeding were the preferred options. The expected genetic gains are satisfactory but largely rely on accurate and continuous pedigree and performance recording.     

鸡法氏囊病毒重组多抗原表位串联肽的制备及其免疫反应

合成含有鸡法氏囊病毒抗原表位核酸序列的4条引物,利用SOE-PCR (重叠延伸PCR法)方法克隆得到含鸡法氏囊病毒多抗原表位串联肽的核酸序列。通过EcoR I和Sal I 两个酶切位点使该核酸序列插入原核表达载体(pET32a)。SDS-PAGE 实验结果表明鸡法氏囊病毒重组多抗原表位串联肽在大肠杆菌中的表达量为20%左右。Western blotting试验和免疫琼脂扩散沉淀试验（AGP）的结果均表明鸡法氏囊病毒重组多抗原表位串联肽具有明显的抗原性。     

High-performance solid Acid fuel cells through humidity stabilization

Although they hold the promise of clean energy, state-of-the-art fuel cells based on polymer electrolyte membrane fuel cells are inoperable above 100 degrees C, require cumbersome humidification systems, and suffer from fuel permeation. These difficulties all arise from the hydrated nature of the electrolyte. In contrast, "solid acids" exhibit anhydrous proton transport and high-temperature stability. We demonstrate continuous, stable power generation for both H2/O2 and direct methanol fuel cells operated at approximately 250 degrees C using a humidity-stabilized solid acid CsH2PO4 electrolyte.     

超声波处理对小麦胚芽球蛋白理化和功能性质的影

采用超声波处理小麦胚芽球蛋白以提高其功能性质.研究了超声波处理对小麦胚芽球蛋白理化和功能性质的影响.结果表明:经超声波处理后,小麦胚芽球蛋白的巯基和二硫键含量、紫外光谱和荧光光谱均发生了显著的变化.随着超声波功率的增加,小麦胚芽球蛋白的疏水性、起泡性、起泡稳定性、乳化性和乳化稳定性都降低;当超声波功率大于900 W时,由于小麦胚芽球蛋白重新伸展,疏水基团暴露增多,引起疏水性、起泡性、起泡稳定性、乳化性和乳化稳定性增加.此外.超声波功率对小麦胚芽球蛋白的溶解度有显著影响,随着超声波功率的增加其溶解度明显增加.因此,通过选择适宜的超声波功率水平能够改善小麦胚芽球蛋白的理化和功能性质.     

牡丹籽油超声波辅助提取工艺的响应面法优

为优化牡丹籽油的超声波辅助提取工艺,在单因素试验基础上,选择液料比、超声波功率、处理时间、处理温度为自变量,牡丹籽油得率为响应值,采用Box-Behnken试验设计方法,研究各自变量及其交互作用对牡丹籽油得率的影响.利用Design Expert软件得到回归方程的预测模型并进行响应面分析,确定超声波辅助提取牡丹籽油的最佳条件为:液料比11 mL/g,超声波功率300 W,处理时间60 min,处理温度54℃,提取次数为3次.在该工艺条件下,牡丹籽油得率达24.12%.GC-MS结果表明牡丹籽油中富含不饱和脂肪酸,其中亚油酸和亚麻酸的质量分数分别为22.78%和64.14%.     

禁捕后长江鱼类资源监测的技术指标建议

为了确定监测时长、监测网具、站位布局对禁捕后长江鱼类资源监测评估的有效性,于2021年5—7月在长江中游10个站位开展了鱼类资源捕捞监测,每个站位连续监测15 d,从日捕获量、物种记录数、渔获物群落结构等3方面着手,对监测时长、监测网具、站位布局等的设置进行探讨。结果显示,连续11 d捕捞监测所得累计日均渔获量基本达到稳定,连续15 d捕捞监测可以记录到站位近70%的鱼类种类数,所得累计鱼类群落结构基本达到稳定。网具类型、规格的使用覆盖对监测结果中鱼类种类记录数、鱼类群落结构有明显影响,网具使用量对监测结果中日均渔获量有明显影响。10个监测站位间的鱼类群落结构具有明显差异,结合监测站位间的空间距离来看,鱼类群落结构具有较高的空间异质性。研究表明,为了保障评估结果的准确性,基于原始监测数据进行相关评估之前,有必要对监测数据的充分性、有效性进行检验,网具类型、规格和使用量对监测结果的影响应予以适当考虑,各具体江段的鱼类群落结构评估应由相应具体江段的监测结果来支撑。本研究将为长江流域重点水域全面禁捕后的水生生物资源监测评估提供科学支撑。     

Breeding programmes for smallholder sheep farming systems: II. Optimization of cooperative village breeding schemes

A simulation study was conducted to optimize a cooperative village‐based sheep breeding scheme for Menz sheep of Ethiopia. Genetic gains and profits were estimated under nine levels of farmers' participation and three scenarios of controlled breeding achieved in the breeding programme, as well as under three cooperative flock sizes, ewe to ram mating ratios and durations of ram use for breeding. Under fully controlled breeding, that is, when there is no gene flow between participating (P) and non‐participating (NP) flocks, profits ranged from Birr 36.9 at 90% of participation to Birr 21.3 at 10% of participation. However, genetic progress was not affected adversely. When there was gene flow from the NP to P flocks, profits declined from Birr 28.6 to Birr ?3.7 as participation declined from 90 to 10%. Under the two‐way gene flow model (i.e. when P and NP flocks are herded mixed in communal grazing areas), NP flocks benefited from the genetic gain achieved in the P flocks, but the benefits declined sharply when participation declined beyond 60%. Our results indicate that a cooperative breeding group can be established with as low as 600 breeding ewes mated at a ratio of 45 ewes to one ram, and the rams being used for breeding for a period of two years. This study showed that farmer cooperation is crucial to effect genetic improvement under smallholder low‐input sheep farming systems.