Bacterial populations on teat ends of dairy cows housed in free stalls and bedded with either sand or sawdust

The main objectives of the experiment were: 1) to compare bacterial populations of mastitis-causing organisms on the teats of lactating dairy cattle housed on sand and sawdust bedding and, 2) to examine the relationship between bacterial counts present in the 2 bedding types with those on teat ends. Sixteen lactating Holstein cows were housed on either sand or sawdust-bedded free stalls using a crossover design with 3 wk per bedding type. Bedding samples were collected on d 0 (prior to animals lying on the bedding), 1, 2, and 6. Teat ends were sampled prior to the morning milking on d 1, 2, and 6. All samples were analyzed to determine coliform, Klebsiella spp., and Streptococcus spp. populations. There were 2 times more coliforms and 6 times more Klebsiella bacteria on teat ends of cows housed on sawdust compared with those housed on sand. In contrast, there were 10 times more Streptococcus spp. bacteria on teat ends of cows when housed on sand compared with sawdust. In both sawdust and sand bedding, coliforms, Klebsiella and Streptococcus counts increased over each experimental week, although patterns varied with bedding and bacteria type. Bacterial counts on teat ends were correlated with bacterial counts in sawdust (r = 0.47, 0.69, and 0.60 for coliforms, Klebsiella spp., and streptococci, respectively) and in sand (r = 0.35 for coliforms and r = 0.40 for Klebsiella spp.). In conclusion, coliforms and Klebsiella spp. on teat ends were more numerous when cows were housed on sawdust bedding, but Streptococcus spp. were more numerous on teat ends of cows housed on sand.     

基于视觉图像识别的番茄表面农药残留量无损检测方法

为了提高对番茄表面农药残留量的准确检测能力,提出一种基于视觉图像识别的番茄表面农药残留量无损检测方法。采用激光成像技术进行番茄表面农药残留区域视觉图像采集,对采集的番茄表面图像进行农药残留量的光谱特征分析,提取番茄表面农药残留区域的边缘轮廓特征,根据特征提取结果进行番茄表面农药残留区域视觉图像重构,在重构的区域图像中采用分块匹配技术进行番茄表面农药残留量区域分割,结合自适应分块特征匹配方法实现番茄表面农药残留量检测识别。仿真结果表明,采用该方法进行番茄表面农药残留量的无损性较好,输出图像的信息饱和度较高,提高了对番茄表面农药残留量的准确检测能力,在番茄病虫害防治和农药的去除等方面具有很好的应用价值。     

假性棉结初探

通过对织物上假性棉结形成原因,分布状况控制措施进行初步探讨,指出假性棉结对斜卡类织物的布面风格有较大影响,其形成原因是经纱与机件反复磨擦,改变了浮游纤维分布状态所致,在布面上的出现规律是斜卡类、经面锻纹类大于类织物;纯棉织物大于涤棉混纺织物,控制好因磨擦产生的毛羽增加率,合理配置工艺及维持适宜的温湿度,假性棉结可以得到有效控制。     

Epiphytic microflora on alfalfa and whole-plant corn.

Epiphytic microflora were identified and counted on four cuttings of alfalfa, each harvested at three stages of maturity, and on three whole-plant corn hybrids. Enterobacteriaceae were predominant on both crops. Yeasts and molds also were major epiphytic microorganisms on whole-plant corn. The group--including lactobacilli, pediococci, and leuconostocs, which are genera that produce lactic acid and thus are instrumental in silage preservation--constituted only a small proportion of the total population (less than .5%) on both crops. Lactate-fermenting clostridial spores were not detected on standing alfalfa, and occurrences of these spores on standing corn plants were due to soil contamination from rainfall prior to harvest. The numbers of epiphytic microorganisms, except for the lactobacilli, pediococci, and leuconostocs group, were higher on standing corn than on alfalfa. The epiphytic microflora on alfalfa increased with increasing temperature during the growing season. However, neither cutting number nor maturity affected the epiphytic microflora on standing alfalfa, and wilting following mowing had little effect on most populations. Higher temperatures during wilting increased yeast and mold counts but had no effect on other microbial counts. The chopping process tended to increase the epiphytic microflora populations compared with those on the standing crops, and the group containing lactobacilli, pediococci, and leuconostocs was most enhanced. Only yeast and mold counts on the chopped alfalfa increased with greater DM content and buffering capacity.     

基于百度指数的传统印染技艺公众关注度分析

以扎染技艺、蜡染技艺和蓝印花布印染技艺为研究对象,基于百度搜索指数分析公众对传统印染技艺的关注度。通过Holt-Winters模型进行序列分解,分析公众关注度的变化趋势和周期特点。结果表明:公众对扎染关注度逐年上升,对蜡染关注度在波动上升后几乎维持不变,对蓝印花布关注度在缓慢上升后有所下降,三者以年为周期波动的规律明显。SARIMA模型对三个序列的预测结果表明:扎染的公众关注度将持续增长,蜡染关注度将基本维持在原有水平,蓝印花布关注度将略有下降。文章从国家政策、人群分布、工艺特点等方面对两种模型所得结论进行解释分析,并给出合理化建议。     

饮料主剂生产中的质量控制

对饮料主剂生产的质量控制，例如进料控制、过程控制、成品控制、不合格品控制以及产品标识和可追溯性控制等进行了论述。     

High-quality forage can replace concentrate when cows enter the deposition phase without negative consequences for milk production

Mobilization and deposition in cows are different strategies of metabolism; hence, the aim was to study the possibility of reducing the crude protein (CP) supply during deposition to limit the use of protein supplements and minimize the environmental impact. A total of 61 Jersey and 107 Holstein cows were assigned to 4 mixed rations in a 2 × 2 factorial design with 2 concentrate to forage ratios (CFR) and 2 CP levels: high CFR (40:60) and recommended CP [16% of dry matter (DM); HCFR-RP], high CFR (40:60) and low CP (14% of DM; HCFR-LP), low CFR (30:70) and recommended CP (16% of DM; LCFR-RP), and low CFR (30:70) and low CP (14% of DM; LCFR-LP), where RP met the Danish recommendations. Cows were fed concentrate in an automatic milking unit. After calving, cows were fed HCFR-RP until entering deposition, defined as 11 kg (Jersey) or 15 kg (Holstein) of weight gain from the lowest weight after calving. Subsequently, cows either remained on HCFR-RP or changed to one of the other mixed rations. Comparing strategies during wk 9 to 30 of lactation showed higher dry matter intake (DMI) of mixed ration on HCFR compared with LCFR and on RP compared with LP. The DMI of the concentrate was higher on LCFR than on HCFR and higher on LP than on RP, resulting in overall higher DMI on HCFR and RP than on LCFR and LP. Crude protein intakes were higher on RP than on LP and starch intakes were higher on HCFR than on LCFR. Intakes of neutral detergent fiber tended to be higher on LCFR than on HCFR. Intakes of net energy for lactation were affected by CFR and CP level, with a higher intake on HCFR and RP than on LCFR and LP. No interactions were found between CFR and CP level for any feed intake variables. Yields of milk and energy-corrected milk were higher on RP than on LP, with no difference in yield persistency after the ration change. Milk composition did not differ among strategies but the protein to fat ratio was higher on HCFR than on LCFR and tended to be lower on RP than on LP. Differences in fatty acid composition were small, and de novo synthesis was high (>60%). Energy efficiency was higher on LCFR than on HCFR and no interaction with breed or parity was found. The N efficiency was higher on LP than RP, but with an interaction with breed due to lower N efficiency in Jersey than Holstein cows on HCFR-RP but higher N efficiency in Jersey than Holstein on LCFR-LP. In dairy production, concentrate in the mixed ration can be substituted with high-quality forage during deposition without negative effects on milk yield and composition when a sufficient CP level is ensured.     

Effects of fasting during mid pregnancy or early lactation on mammary development and milk yield in mice

Mice were fasted during pregnancy or early lactation and the effects on mammary development and milk yield studied on d 13 and d 18 of pregnancy and on d 7 of lactation. Fasting during pregnancy reduced body weight and mammary weight on d 13 of pregnancy but not on d 18. Mammary concentrations and total contents of DNA and RNA ([DNA], [RNA], DNAt, RNAt) were increased or unchanged on d 13 but significantly decreased on d 18. Fasting had no effect on fetal number or weight at either stage of pregnancy. Fasting on d 1 of lactation reduced mammary weight, DNAt and RNAt (but not [DNA] or [RNA]) and the incorporation of tritiated thymidine into DNA or d 2 of lactation. Mammary gland weight and composition on d 7 of lactation were not significantly affected by fasting for 24 h on d 1 of lactation or for 40 h on d 11-13 of pregnancy, except that DNAt was decreased slightly by the latter treatment. Milk yield (litter weight gain) was depressed markedly during fasting on d 1 of lactation, but thereafter recovered so that it was the same as controls between d 3 and 13 of lactation; after d 13 it fell once more. A 40 h fast on d 11-13 of pregnancy had no effect on milk yield. Thus, although normal mammary development was inhibited by starvation, the gland was subsequently able to compensate so that milk yield was not reduced.     

男式衬衫领纸样设计研究

分析了颈部对领子纸样的影响,通过实验的方法研究了面料性能与衬衫领下落量之间的关系,分析了面料的缩水率和热缩率对衬衫领尺寸的影响,找出了衬衫领纸样设计中的3个主要因素的影响规律。研究结果表明:领子纸样设计中前颈点、侧颈点以及后颈点与颈部构造有密切关系,并指出颈部倾斜形态对纸样的影响;面料的拉伸比功、拉伸功回复率、压缩功回复率、单位面积重量等4个主要性能指标对下落量有影响;在确定领子样板尺寸时必须考虑面料的缩水率和热缩率对其的影响。     

Effects of surface ageing on wettability, surface chemistry, and adhesion of wood

The effects of ageing on the surface chemistry, wettability and the surface free energy were determined according to the acid base theory using contact angle measurements and x-ray photoelectron spectroscopy. Time is a significant variable affecting wettability and adhesion. All measured surface parameters of the wood surface were storage time dependent. It could be demonstrated that the effect of ageing on the adhesion of a coating on the wood surface depends not only on the properties of the wood surface, but also on the chemical nature of the coating. Therefore, measurements on wettability without considering the time dependence of surface energy and, above all, its components, are not sufficient to assess effects of ageing on adhesion.     

果蔬贮藏保鲜产业现状、研究进展与科技支持

简要介绍了我国果蔬贮藏保鲜的现状,指出了当前果蔬贮藏的主要问题。论述了国内外有关果蔬贮藏保鲜的新技术及研究进展情况,包括:天然果蔬保鲜剂的研究、利用调压技术贮藏、臭氧及负氧离子保鲜、利用生物技术保鲜、静电场处理贮藏、低剂量辐射处理和紫外线处理保鲜以及细胞水结构化气调保鲜等国内外近几年发展起来的现代果蔬贮藏保鲜技术。并阐述了科技对我国果蔬贮藏保鲜产业的支撑作用。     

解读香港《食物内除害剂残余规例》

《食物内除害剂残余规例》是香港首部除害剂管理法规,本文从香港《规例》的形成背景着手,介绍了其制定历史,探讨了国际食品法典委员会、中国内地、美国和泰国4方标准的具体内容及《规例》的采标情况,同时介绍了香港《食物内除害剂残余规例使用指引》中的食物分类概况。本文针对香港的食物监察计划逐一讨论,介绍了监察计划的种类及监察项目;同时介绍了香港政府有关规例检测的技术规范要求及相关的参考标准体系,并对中国内地的农残标准修订、检测技术规范及执行评判标准提出了建议。     

三点弯曲工况下复合材料层合板的应力变化

为研究三点弯曲工况下复合材料层合板的应力问题,基于连续介质损伤力学以及Hashin失效准则,建立复合材料层合板三点弯曲有限元模型。模拟三点弯曲成形过程,讨论成形过程中应力分布及变化规律。结果表明:0°铺层应力值始终高于90°铺层,下表面的应力值小于上表面,但下表面的应力值达到最大值的时间要早于上表面;沿X轴方向,越接近压头位置,上下表面的应力差越小,在板料端部上下表面应力值相等;沿Y轴方向,上下表面的应力值变化幅度较小,上下表面的应力差基本保持不变。     

我国木材材种识别技术的新进展

介绍了传统的板材识别方法,包括人工经验识别法、对分式检索表法和穿孔卡片检索表法.总结了基于计算机识别技术的各种木材识别方法:数据库查询检索法、木材图像识别法、利用神经元网络和木材表面颜色特征对木材进行分级的方法、基于语义数据模型的识别方法、基于最大相似原理的材种判别法和木材细胞模型系统的研究进展,重点论述了基于板材端面细胞实体检测图像的数字特征参数识别法.还总结了木材识别理念的更新和进展,指出基于板材端面细胞实体检测图像的数字特征参数识别法大幅度地加快了识别和比较计算的速度,减少了传统依赖图像像素特征识别比较的不确定性.     

基于高通量测序技术分析不同地区自然陈化广陈皮表面微生物群落多样性

采用高通量测序技术对不同地区自然陈化1年广陈皮表面微生物群落多样性进行分析,比较群落结构的差异。结果表明,不同地区自然陈化1年广陈皮微生物丰富度和多样性差异不显著（P＞0.05）,群落结构相似,但相对丰度存在差异。北京地区优势细菌属为Methylocella、苔藓杆菌属（Bryobacter）等,优势真菌属为短梗霉属（Aureobasidium）、炭疽菌属（Colletotrichum）等;四川地区优势细菌属为甲基杆菌属（Methylobacterium）、鞘氨醇单胞菌属（Sphingomonas）、芽孢杆菌属（Bacillus）、乳球菌属（Lactococcus）等,优势真菌属为Symmetrospora、曲霉属（Aspergillus）等;广东地区优势细菌属为Rubellimicrobium、乳杆菌属（Lactobacillus）等,优势真菌属为假尾孢属（Pseudocercospora）、毛壳菌属（Chaetomium）等;云南地区优势细菌属为罗尔斯顿菌属（Ralstonia）、Glutamicibacter等,优势真菌属为平脐疣孢属（Zasmidium）、拟暗球腔菌属（Phaeosphaeriopsis）等。     

Hygicult载片培养法快速检测表面大肠菌群的效果评价

为探讨Hygicult裁片培养法快速检测食品生产加工单位和餐饮单位环节表面大肠菌群的效果，对代表3种不同清洁程度的保健品生产单位、裱花蛋糕生产单位和餐饮单位的636件环节样品，以及实验室人工污染标准大肠杆菌的样品分别用栽片培养法和常规发酵法进行检测，比较两种检测方法的符合率。在现场样品中，两种检测方法的总体符合率为97．6％，其中，按食品行业分类，保健品生产单位、裱花蛋糕生产单位和餐饮单位样品检测结果的符合率分别为98．0％。96．2％和93．8％；按样品种类分类：容器、工具、操作台、手、裱带、碗碟、砧板和刀具检测结果的符合率分别为100％、100％、100％、100％、96．5％、96．4％、93．2％和89．2％；按样品材质分类：不锈钢、瓷器、手、塑料、木质和布质检测结果的符合率分别为100％、100％、96．5％、95．0％、91．8％和89．2％；上述两法检测结果比较均差异无显著性（P〉0．05）。在实验室人工污染样品中，两种检测结果一致。Hygicult载片培养法可以代替常规发酵法作为食品行业环节表面大肠菌群污染的快速检测方法。     

Reducing dry period length to simplify feeding transition cows: milk production, energy balance, and metabolic profiles

Sixty-five Holstein cows were used to evaluate management schemes involving altered dry period (DP) lengths on subsequent milk production, energy balance (EB), and metabolic variables. Cows were assigned to one of 3 treatments: traditional 56-d DP (fed a low-energy diet from -56 to -29 d and a moderate energy diet from -28 d to parturition; T), 28-d DP (continuously fed a high energy diet; S), and no planned DP (continuously fed a high energy diet; N). Prepartum DM intake (DMI), measured from 56 d prepartum through parturition, was lower for cows on the T treatment than for cows on the S treatment and was higher for cows on the N treatment than for cows on the S treatment. There were no differences in prepartum plasma glucose, and beta-hydroxybutryric acid; there was a treatment by time interaction for prepartum plasma nonesterified fatty acid (NEFA). There was no difference in prepartum liver triglyceride (TG); postpartum liver TG was decreased for cows on the N treatment compared with cows on the S treatment, but was similar for cows on the T and S treatments. Postpartum NEFA was similar between cows on the T and S treatments, but was greater for cows on the S treatment than for cows on the N treatment. Postpartum glucose was greater for cows on the N treatment compared with cows on the S treatment and tended to be greater for cows on the S treatment than for cows on the T treatment. There was no difference in postpartum solids-corrected milk (SCM) production or DMI by cows on the T vs. S treatment. However, there was a tendency toward lower postpartum SCM production by cows on the N vs. S treatment and a tendency for greater postpartum DMI by cows on the N vs. S treatment. Postpartum EB was greater for cows on the S vs. T treatment and the N vs. S treatment. In general, T and S management schemes had similar effects on DMI, SCM, and metabolic variables in the first 70 d of the subsequent lactation. Eliminating the DP improved energy and metabolic status.     

Macrominerals in guinea pig milk during 21 days of lactation

Milk samples were obtained daily from English short-hair albino guinea pigs for 21 d. Analyses included six macrominerals: Ca, P, K, chloride, Na, and Mg (in order of decreasing concentration). All minerals except K gradually increased in concentration from the beginning to the end of lactation. Calcium concentration began at 38 mM on d 1 and was 78 mM on d 21. The pattern of increase was quadratic: Y (mM) = 39 -.48X (day of lactation) + .11 X2. Phosphorus concentration was 38 mM on d 1 and highest at 51 mM on d 21. Chloride was 19 mM on d 1 and 68 mM on d 21. Sodium was 13 mM on d 1 and highest at 42 mM on d 21. Magnesium was 11 mM on d 1 and was highest on d 18 (13 mM). However, K was 31 mM on d 1, reached a high of 33 mM on d 3, and was lowest on d 19 (12 mM). These changes in concentration and previously reported volume changes suggest alterations in functional capacities of ionic transport mechanisms of secretory cell membranes in this species.     

H2O2和NaHS对几种脱毛酶活力的影响

采用福林法和紫外分光光度法分析了几种蛋白酶活力的pH值曲线,并探讨了H2O2及NaHS对它们酶活力变化的影响.结果表明H2O2对NOWOLASE PE酶的活力影响较小,且具有一定的激活作用,而对2709酶、A.S1398酶和Basozym L10酶的影响极大;NaHS对2709酶和A.S1398酶的活力影响较小,且对2709酶的活力具有稳定作用,而对NOWOLASE XL酶、NOWOLASE PE酶和Basozyme L10酶的影响大.此结果为研究H2O2和NaHS辅助蛋白酶脱毛,以解决酶脱毛中小毛不易脱净的缺陷打下基础.     

The effect of substrate on mycotoxin production of selected Penicillium strains

Analytical methods are presented for detecting simultaneously 11 fungal metabolites (aflatoxins B1, B2, G1 and G2, citrinin, cyclopiazonic acid, mycophenolic acid, ochratoxin A, penicillic acid, penitrem A and roquefortine C) on different matrices. The methods were applied to determine the mycotoxins produced by different Penicillium crustosum, Penicillium nordicum and Penicillium verrucosum strains on yeast extract sucrose (YES) agar and cheese and bread analogues and are based on high-performance liquid chromatography (HPLC) and photodiode array detection (PDA). The growth substrate had a distinctive effect on the mycotoxin production ability of the fungi examined. The P. crustosum strains produced roquefortine C on all the substrates, with the highest amounts being detected on the cheese analogue. Penitrem A was synthesised on the cheese analogue only. The strains of P. verrucosum produced exclusively citrinin on YES, but both ochratoxin A and citrinin were detected in considerable amounts on the bread analogue. On the bread, toxin profiles varied significantly between the individual P. verrucosum strains. The cheese analogue was not favourable for the mycotoxin production of this species. The growth substrate had the least effect on the toxin production of the P. nordicum strains, which synthesised ochratoxin A in moderate amounts on all three media.