地木耳细胞的破碎和藻蓝蛋白提取工艺的研究

以地木耳干粉为原料,比较研究了反复冻融法、超声波法及反复冻融结合超声波法地木耳细胞破碎的效果,得出最优细胞破碎方法,并对细胞破碎液利用超声波法进行提取工艺研究,经过单因素分析及正交试验得出超声波法提取的最佳工艺条件。结果表明,反复冻融结合超声波法的地木耳细胞破碎效果最好,破碎液中地木耳藻蓝蛋白的提取率为0.070 1%,是反复冻融法的3.8倍,是超声波法的1.1倍;超声波法提取地木耳藻蓝蛋白的最佳工艺条件为:超声时间25 min,超声功率600 W,提取溶剂pH 6.0,提取液中地木耳藻蓝蛋白的提取率为0.484 6%,是细胞破碎液中的1.8倍。     

两种乳酸杆菌超声破碎提取亚油酸异构酶条件的研究

本文利用超声波对两种乳酸杆菌细胞进行破碎,以提取细胞中的亚油酸异构酶,并就超声波破碎条件对亚油酸异构酶释放的影响进行了研究。通过单因素试验和正交试验得出嗜酸乳杆菌的最佳超声破碎条件为:间歇破碎次数80次(每次破碎3s,中间间隔4s),破碎菌液体积50ml,菌悬液浓度20g/60ml,破碎时的抽提缓冲液最佳pH值4.0,NaCl浓度0.2mol/L;保加利亚乳杆菌的最佳超声破碎条件为:间歇破碎次数80次(每次破碎3s,中间间隔4s),破碎菌液体积60ml,菌悬液浓度15g/50ml,破碎时的抽提缓冲液最佳pH值4.8,NaCl浓度0.3mol/L。     

超声波破碎提取D-甘露糖异构酶条件的研究

利用超声波对假单胞菌属No.2120(Pseudomonas SP.No.2120)细胞进行破碎,研究了利用超声波法破碎时输出功率(W)、每次辐射时间(s)、工作总时间(min)、每克细胞的缓冲液加入量(mL/g)等因素对D-甘露糖异构酶酶活的影响.通过单因素实验和正交实验得出超声波破碎的最佳工艺条件为:输出功率450W,每次辐射时间5s(间歇时间5s),工作总时间5.5min,每克细胞的缓冲液加入量为5mL/g.     

红景天黄酮提取技术的研究

以长白山区产红景天为原料,以超声波破碎为辅助手段,热水浸提红景天黄酮。采用正交试验法对影响超声波处理效果及红景天黄酮提取率的主要因素进行研究和分析,并筛选出最佳工艺条件。结果表明超声波破碎条件为:物料粒度0.125mm,超声波作用时间6s,间隔时间4s,破碎次数7次;红景天黄酮热水浸提最佳条件为:浸提时间40min,固液比1:15,浸提温度80℃。按此工艺条件,红景天黄酮的提取率达到13.02% 。     

超声波技术在玉米浆饮料生产中的应用

选用东北优质甜玉米,采用超声波破碎技术对普通玉米浆生产工艺进行改良。通过单因素和正交试验的方法,初步确定超声波破碎生产玉米浆饮料的工艺条件为破碎功率600W、破碎时间7s/ 次(共30 次)、料水比1:3(m/m)。比较采用超声波破碎工艺与普通破碎工艺得到的玉米浆产品,最终确定采用超声波破碎法生产玉米浆饮料的工艺,最优条件为玉米浆质量分数100%、超声波破碎料水比1:3(g/mL)、糊化温度90℃、糊化时间4min、稳定剂用量0.05%。制得的玉米浆饮料口感滑润、气味芳香、色泽微黄、营养丰富。     

超声波破碎法提取瑞士乳杆菌氨肽酶条件的优化

目的：确定超声波破碎细胞提取瑞士乳杆菌氨肽酶的最佳条件。方法：采用单因素试验和响应面法对菌体浓度、超声波破碎功率、破碎时间进行研究。结果：菌体浓度、超声波破碎功率、破碎时间对超声波破碎程度都存在一定的影响,其中破碎时间影响最为显著。超声波破碎提取氨肽酶的最适条件为菌体浓度0．0238g／ml,破碎功率300W,破碎总时间26min（超声3s,间隔5s）。破碎后得到粗酶液总酶活力为72．99U。结论：采用超声波破碎方法可以较好地提取氨肽酶,运用响应面分析法优化超声波破碎条件是可行的。     

螺旋藻蛋白提取方法比较研究

采用超声波法、高压均质法和反复冻融法对螺旋藻细胞进行破碎,确定破碎条件和螺旋藻蛋白溶出率。结果表明:在各自的最佳提取条件下,超声波法得到的蛋白溶出率为71.51%,高压均质法得到的藻胆蛋白溶出率为73.87%,反复冻融法得到的蛋白溶出率为72.03%。     

破碎方法对醋酸菌中ADH活性的影响

采用不同的破碎方法对同一株醋酸菌菌体进行破碎,结果表明,采用溶菌酶-超声波联合破碎法,破碎效果更佳,ADH酶活力也更高。通过单因素和正交试验确定溶菌酶-超声波联合破碎法的最佳破碎条件:溶菌酶用量为0.04mg/mL,酶解时间为20min,酶解温度为30℃,超声波累计破碎时间为2.5min。     

超声波破碎法提取羊肚菌发酵菌丝体生物活性肽条件的优化

以羊肚菌发酵菌丝为原料,采用单因素试验法、正交试验法、超声波破碎试验法对羊肚菌发酵菌丝生物活性肽提取条件进行研究。结果表明:羊肚菌发酵菌丝体预处理的最佳条件为料:水=1:12,pH为8,反复冻融3次;羊肚菌发酵菌丝体生物活性肽的最佳提取条件是超声波破碎仪参数为超声波破碎次数120次,工作时间为5 s,间歇时间为5 s,功率为600 W,乙醇浓度为85%,醇:提取液=1:1.5,提取温度为45℃,在最佳条件下生物活性肽的含量为9.85 mg/g。     

超声波酸性丙酮法制备氯化血红素

研究一种利用猪血制备氯化血红素的新工艺,将超声波细胞破碎应用于酸性丙酮- 乙酸钠法制备氯化血红素。利用红外光谱法和紫外- 可见光谱法对氯化血红素产品进行表征,紫外光谱法进行氯化血红素产品含量测定。结果表明：超声波细胞破碎的最佳工艺条件为超声波功率0.8kW、破碎剂(水:乙醇,V/V)比例15:1、破碎时间6min,该法所得产品的含量为92.67%,得率为86.62%。此法可操作性强、成本低、产品纯度高。     

固定化酵母生产蜂蜜酒的研究

对固定化酵母生产蜂蜜酒的工艺条件进行了研究，通过L9(3^4)正交试验确定了最适固定化条件为Na-Alg 1．0％，CaCl2 1．0％，固定化时间1h，7#针头凝胶球；最佳发酵条件为底物浓度18％，pH4．2，32℃，接种量1．4％。(丹妮)     

Short-term effect of transition from conventional to automated milking on teat skin and teat end condition

A higher milking frequency, as a consequence of milking with an automated milking system, incorporates a threat to teat condition. To study the effect of transition from conventional to automated milking on teat skin and teat end condition, 40 lactating Holstein-Friesian cows and heifers from a high yielding dairy herd were randomly allocated to either a conventional or an automated milking system group. In the latter group, automated milking was initiated during the study period, while conventional milking was continued in the control group. Teat skin and teat end condition were evaluated weekly on quarter level for all animals from 5 wk before until 8 wk after transition. A high emollient iodine teat dip was used on all cows during the study period. Teat skin condition of the animals in the automated milking system group was consistent from before and during milking with the automated milking system. Rear teats had a better skin and end condition than front teats. Evolution of teat end condition over time between the automated and conventional milking groups was not statistically different. Heifers, however, seemed to be more sensitive to the change than multiparous cows, as their teat end condition slightly decreased.     

Pre-conception energy balance and secondary sex ratio--partial support for the Trivers-Willard hypothesis in dairy cows

According to the Trivers-Willard hypothesis, maternal condition at or around conception affects the secondary sex ratio in mammals. However, there are little or no data available on indicators of maternal condition in dairy cows on the sex of the resultant offspring. A total of 76,607 body condition score (BCS; scale of 1 to 5) records and 76,611 body weight (BW) records from 3,209 lactations across 1,172 cows were extracted from a research database collated from one research herd between 1986 and 2004, inclusive. Exclusion of multiple births and cows with no information before calving (e.g., nulliparous animals) resulted in 2,029 records with BCS and BW observations from the previous calving, and 2,002 and 1,872 lactations with BCS and BW observations at conception and midgestation, respectively. Change in BCS and BW between calving and conception and between conception and midgestation was calculated per lactation. Generalized estimating equations were used to model the logit of the probability of a male calf, in which cow was included as a repeated effect with a first-order autoregressive correlation structure assumed among records within cow. Of the BCS variables investigated, there was a linear relationship between the logit of the probability of a male calf and BCS change between calving and conception, the rate of BCS change over this period (BCS divided by days in milk), and BCS at the calving event immediately before conception. The birth of a bull calf was 1.85 times more likely in cows that lost no BCS from calving to conception compared with cows that lost one BCS unit from calving to conception. This increase in odds was equivalent to a 14% unit increase in the probability of a male calf (from 54 to 68%). The amount of BW lost between calving and conception and the rate of loss affected the sex of the resultant offspring. Less BW loss or greater BW gain between calving and conception was associated with greater likelihood of a male calf. Results suggested a positive effect of pre-conception BCS and BW change on secondary sex ratio, agreeing with the Trivers-Willard hypothesis that females in good physiological condition are more likely to produce male offspring.     

中国毛皮行业现状

从毛皮生产及进出口状况,分析中国毛皮行业面临的现状,并对未来发展进行预测。     

牛顿迭代法收敛速度分析

根据一阶导数的性质,讨论了在一些相对弱的条件下牛顿迭代法的超线性收敛性,得到了迭代法的收敛因子.在Visual C 环境下的数值实验表明,近似效果良好.     

大豆异黄酮提取条件的研究

本文主要研究了乙醇-水体系提取大豆异黄酮的工艺条件,经单因子实验与L9（3^4)正交实验,最终得到了该体系的最佳提取条件,如以总异黄酮作为提取目的,最佳条件为：80%的乙醇浓度,不小于18：1的物料比（溶剂：原料）,时间1h,温度不超过50℃;如以genistin作为目的产物,则温度宜升高至70℃。     

Evaluation of body condition score measured throughout lactation as an indicator of fertility in dairy cattle

Body condition score (BCS) records of primiparous Holstein cows were analyzed both as a single measure per animal and as repeated measures per sire of cow. The former resulted in a single, average, genetic evaluation for each sire, and the latter resulted in separate genetic evaluations per day of lactation. Repeated measure analysis yielded genetic correlations of less than unity between days of lactation, suggesting that BCS may not be the same trait across lactation. Differences between daily genetic evaluations on d 10 or 30 and subsequent daily evaluations were used to assess BCS change at different stages of lactation. Genetic evaluations for BCS level or change were used to estimate genetic correlations between BCS measures and fertility traits in order to assess the capacity of BCS to predict fertility. Genetic correlation estimates with calving interval and non-return rate were consistently higher for daily BCS than single measure BCS evaluations, but results were not always statistically different. Genetic correlations between BCS change and fertility traits were not significantly different from zero. The product of the accuracy of BCS evaluations with their genetic correlation with the UK fertility index, comprising calving interval and non-return rate, was consistently higher for daily than for single BCS evaluations, by 28 to 53%. This product is associated with the conceptual correlated response in fertility from BCS selection and was highest for early (d 10 to 75) evaluations.     

阻尼边界条件障碍在分层介质中声波散射问题的数值算法

讨论了阻尼边界条件障碍在两层介质中声波散射问题的数值解法。利用单双层位势组合及跳跃关系理论,将其转化为边界积分方程组求解问题,再利用Nystr？m法,将积分方程组离散化为线性方程组。对不同形状的边界给出数值算例,以验证此方法的可行性与有效性。     

制约大曲质量品质的条件剖析及前景展望

通过对传统大曲生产原理分析和大曲在浓香型大曲酒发酵体系中生化演化原理分析，推论得出制曲环境自然条件是影响大曲质量品质的不可控制条件，制曲工艺技术及曲坯发酵过程管理是影响大曲质量品质的可控制条件，生产质量稳定、品质卓越的大曲，两者缺一不可。同时也提出充分利用有利条件形成专业大曲生产基地，推动浓香型大曲酒业的整体发展。     

产愈创木酚类细菌的培养条件优化

采用响应面试验对产愈创木酚细菌的培养条件进行优化。以从某酒厂窖泥中筛选到的高产愈创木酚的戴尔福特菌（Delftia sp.）为基础,考察不同因素对细菌产愈创木酚的影响。首先采用单因素试验对麸曲培养基水分含量、培养温度、培养时间和接种量进行分析优化,然后根据单因素试验结果采用响应面试验对培养条件进行优化。结果表明,影响细菌产愈创木酚的因素主次顺序为培养温度＞接种量＞培养时间＞水分,细菌产愈创木酚最佳工艺条件为水分81.5%、培养时间50 h、接种量11.0%、培养温度38 ℃。在此优化条件下,愈创木酚类物质含量为3.89×10-4 g/g。