Generation of Airborne Particles from Horse Feeds Depending on Type and Processing     

Engel F. Hessel  Felix GarlippHerman F.A. Van den Weghe  Prof Dr Ir 《Journal of Equine Veterinary Science》2009

Among other factors (eg, bedding material, roughage), feed has an important effect on the airborne particle concentration in the stable air, in particular directly in the breathing zone of the horse during feeding. Therefore, this study was designed to analyze and compare the generation of different airborne particle fractions of diverse feed types and feed processing techniques under standardized laboratory conditions. Oats and barley as well as two commercially formulated ready-prepared pellets and two different commercially formulated ready-prepared mixes were analyzed. Oats were subjected to four different forms of processing (whole uncleaned, whole cleaned, rolled uncleaned, rolled cleaned), barley was subjected to steam flaking in addition to the same forms of processing as oats. In total, 13 feeds were analyzed. Airborne particle concentrations were detected online with a gravimetrically measuring analyzer that was equipped successively with different inlets to measure the particle fractions PM 1, PM 2.5, PM 10, and PM 20. The measurements were carried out in a closed chamber (1 × 1 × 1.5 m) including a bowl (diameter = 0.5 m), which simulated the trough. The sample inlet was situated at a height of 1.0 m above the bowl. Rolling oats and barley led to a significantly increased generation of the PM 20 fraction and a significantly decreased generation of the PM 2.5 fraction. The mechanical cleaning of oat and barley brings a clear decrease in dust generation from straights whether they are left whole or are rolled after cleaning. A considerable reduction in dust generation can be achieved if steam-flaked barley or commercially prepared feeds are used.  相似文献   

An intratracheal instillation bioassay system for detection of lung toxicity due to fine particles in f344 rats     

Yokohira M  Kuno T  Yamakawa K  Hashimoto N  Ninomiya F  Suzuki S  Saoo K  Imaida K 《Journal of toxicologic pathology》2009,22(1):1-10

It is an urgent priority to establish in vivo bioassays for detection of hazards related to fine particles, which can be inhaled into deep lung tissue by humans. In order to establish an appropriate bioassay for detection of lung damage after particle inhalation, several experiments were performed in rats using quartz as a typical lung toxic particle. The results of pilot experiments suggest that Days 1 and 28 after intratracheal instillation of 2 mg of fine test particles in vehicle are most appropriate for detection of acute and subacute inflammatory changes, respectively. Furthermore, the BrdU incorporation on Day 1 and the iNOS level on Day 28 proved to be suitable end-point markers for this purpose. An examination of the toxicity of a series of particles was performed with the developed bioassay. Although some materials, including nanoparticles, demonstrated toxicity that was too strong for sensitive assessment, a ranking order could be clarified. The bioassay thus appears suitable for rapid hazard identification with a possible ranking of the toxicity of various particles at single concentrations.  相似文献   

双组分吸附流化床干燥酵母醪液的工艺参数     

罗乔军  张进疆  龚丽  刘清化  陈明 《农产品加工．学刊》2009,(10)

双组分吸附流化床应用到酵母醪液的干燥中,改善了混合物料的流化性能,提高了干燥效率。详细讨论了温度对吸附流化床干燥的影响,以及不同质量混合比物料的流化特性,提出了饲料生产的过程参数。  相似文献   

新城疫病毒样颗粒(ND-VLPs)免疫效力的研究     

吴芬芳  闫丽辉  曹殿军  刘培欣  闻晓波  孔宪刚 《中国预防兽医学报》2008,30(1):42-46,63

为了研究ND-VLPs的免疫原性,利用共表达NDV F、HN、NP和M蛋白的重组杆状病毒rBac-F-HN-NP-M感染Sf9细胞,采用蔗糖密度梯度离心法纯化释放到细胞培养上清的VLPs,免疫60只,18日龄SPF鸡,监测血清中NDV特异性抗体滴度的变化.2周后用相同剂量的VLPs加强免疫.二免后2周以3.16×103EID50的F48E9株强毒滴鼻攻毒.攻毒前,La Sota灭活苗、La Sota 20μg VLP和不同剂量VLPs组(10 μg、20 μg、25 μg)HI效价分别为28.3、28.9、24.1、26.1、26.7;攻毒后,10 μg和20 μg VLP免疫组仅能提供了80%和90%的保护率,但与La Sota灭活苗、La Sota 20 μg VLP一样,25 μg VLP试验组却能够完全抵抗致死剂量的NDV强毒攻击.本试验表明,ND-VLPs具有良好的免疫原性,25 μg VLP诱导机体产生的免疫应答能抵抗致死剂量强毒的攻击.ND-VLPs有可能用来研制针对新城疫流行变异株的高效疫苗.  相似文献   

示踪粒子跟随性讨论   总被引：9，自引：1，他引：8  

严敬  杨小林  邓万权  刘忠  季全凯  万毅 《农业机械学报》2005,36(6):54-56

在叶轮内流场的非接触式测试中,必须在流场中置入随流前进的示踪粒子。以数学分析方法详细计算讨论了提高粒子跟随性的条件,即为改善测试结果的可靠性,在测试系统光学设备可辨识的条件下,选用的粒子的粒度应尽量小。这一结论将有助于提高流场测试精度。  相似文献   

盐单胞菌合成纳米钯催化污染物的还原     

汪文静  丁诗婷  张玲  程园园 《安徽农业大学学报》2020,47(4):559

从浙江舟山盐场筛选出一株盐单胞菌Halomonas salina JX-1,能够合成金属钯纳米颗粒,并应用于催化六价铬Cr(VI)的还原及有机偶氮染料甲基橙（MO）的脱色。通过透射电子显微镜（TEM）、X射线衍射（XRD）、X射线光电子能谱分析（XPS）等分析证实合成了零价纳米钯颗粒。对钯纳米颗粒合成条件的优化实验的结果表明,在菌量OD₆₀₀=1.0、无氯化钠、以甲酸为电子供体时,细菌还原钯的速率最快。电子穿梭体核黄素可加快钯离子还原成钯纳米颗粒。纳米钯颗粒在24 h内对Cr(VI)的还原率高达99%,在1.5 h内对甲基橙的降解率也几乎达到100%。综上,Halomonas salina JX-1合成的纳米钯颗粒对Cr(VI)及甲基橙都有很高的催化活性。  相似文献   

Molecular evolution of tomato black ring virus and de novo generation of a new type of defective RNAs during long-term passaging in different hosts     

Daria Budzyńska  Julia Minicka  Beata Hasiów-Jaroszewska  Santiago F. Elena 《Plant pathology》2020,69(9):1767-1776

Tomato black ring virus (TBRV) is a worldwide-distributed RNA virus infecting a wide range of different host plants, including crop species, trees, shrubs, and weeds. Here, we investigated the molecular evolution of TBRV and its adaptability to different plant species. The TBRV-Pi isolate was used to generate five independent evolution lineages serially passaged in either quinoa, tobacco, or tomato plants. After 15 passages, the genetic variability present in all the lineages was characterized for the movement (MP) and coat (CP) coding cistrons. We addressed two main questions: to what extent does the amount of genetic variability in the TBRV genome depend on the host species, and are there host species-specific adaptive mutations? Overall, 201 different nucleotide substitutions emerged during the evolution experiment, with some of them appearing multiple times in different lineages; two of them (one in CP and one in MP) were unique for a particular host plant. We have shown that the degree of genetic differentiation depends on the host species in which the virus evolved, and that positive selection is operating upon certain residues, particularly in CP. Moreover, we have characterized new types of defective RNAs that arose during the TBRV-Pi evolution in tobacco. Furthermore, this is the first report of a defective RNA from the RNA2 of TBRV.  相似文献   

Use of caesium-137 data for validation of spatially distributed erosion models: the implications of tillage erosion     

Timothy A. Quine 《CATENA》1999,37(3-4)

Validation of spatially distributed models using spatially distributed data represents a vital element in the development process; however, it is rarely undertaken. To a large extent, this reflects the problems associated with assembling erosion rate data, at appropriate temporal and spatial scales and with a suitable spatial resolution, for comparison with model results. The caesium-137 (¹³⁷Cs) technique would appear to offer considerable potential for meeting this need for data, at least for longer timescales. Nevertheless, initial attempts to use ¹³⁷Cs for model validation did not prove successful. This lack of success may be explained by the important role of tillage erosion in redistributing soil within agricultural fields and, therefore, contributing to the ¹³⁷Cs-derived soil redistribution rates. This paper examines the implications of tillage erosion for the use of ¹³⁷Cs in erosion model validation and presents an outline methodology for the use of ¹³⁷Cs in model validation. This methodology acknowledges and addresses the constraints imposed by the need to: (1) separate water and tillage erosion contributions to total soil redistribution as represented in ¹³⁷Cs derived rates; (2) account for lateral mixing of ¹³⁷Cs within fields as a result of tillage translocation; (3) simulate long-term water erosion rates using the model under evaluation if ¹³⁷Cs-derived water erosion rates are to be used in model validation. The methodology is dependent on accurate simulation of tillage erosion and tillage translocation. Therefore, as greater understanding of tillage erosion is obtained, the potential for the use of ¹³⁷Cs in water erosion model validation will increase. Caesium-137 measurements remain one of the few sources of spatially distributed erosion information and, therefore, their potential value should be exploited to the full.  相似文献   

牙鲆养殖循环系统中固体废物的粒径分布与沉降特征   总被引：4，自引：1，他引：3  

刘长发  徐岩  晏再生  朱学惠  王欣然  张俊新  何洁 《渔业现代化》2009,36(6):1-5

沉淀槽是收集系统中固体废物的最简单装置,其设计参数与其沉淀的颗粒物特性有关。通过研究牙鲆（Paralichthys olivaceus）养殖循环系统产生固体废物的粒径分布和沉降特征,得到了牙鲆养殖固体废物去除的沉淀槽设计参数——溢流率与颗粒物去除效率间的关系,可作为设计沉淀槽时参考。结果表明：系统产生固体废物量为0.13-0.27 kg TSS/kg饲料,平均为（0.22±0.06）kg TSS/kg饲料。沉淀槽中固体废物主要为粒径〈200μm的颗粒,占51.5%,其粒径分布符合双曲线型分布。在给定溢流率的情况下,沉淀槽的固体废物理论去除效率可采用颗粒物的沉降曲线估算。溢流率为1/16 m3/（m2.s）时计算的颗粒物理论去除效率为81%。  相似文献   

应用细菌磁颗粒实时荧光RT-PCR检测南瓜花叶病毒   总被引：1，自引：0，他引：1  

孙宁  邓丛良  么磊  陈继峰 《植物病理学报》2010,40(6):632-635

 A novel real-time RT-PCR method, BMPs based real-time RT-PCR which integrated with magne-tic separation technique of bacterial magnetic particles(BMPs), was set up for detection of Squash mosaic virus(SqMV).After SqMV particles in crude sap were concentrated by BMPs, viral RNAs were released and detected by real time RT-PCR.The results indicated that BMPs based real-time RT-PCR was efficient, and the detection sensibility was equivalent to that of the Trizol based real-time RT-PCR, of which Trizol reagent was used for viral RNAs extration.Comparing to Trizol-based method, the BMPs-based method had advantages of simplicity on operation, time saving for RNA extraction and without using noxious organic chemicals.  相似文献