Genetic analysis of detailed milk protein composition and coagulation properties in Simmental cattle

The objective of this study was to estimate genetic parameters for milk protein fraction contents, milk protein composition, and milk coagulation properties (MCP). Contents of α_S1-, α_S2-, β-, γ-, and κ-casein (CN), β-lactoglobulin (β-LG), and α-lactalbumin (α-LA) were measured by reversed-phase HPLC in individual milk samples of 2,167 Simmental cows. Milk protein composition was measured as percentage of each CN fraction in CN (α_S1-CN%, α_S2-CN%, β-CN%, γ-CN%, and κ-CN%) and as percentage of β-LG in whey protein (β-LG%). Rennet clotting time (RCT) and curd firmness (a₃₀) were measured by a computerized renneting meter. Heritabilities for contents of milk proteins ranged from 0.11 (α-LA) to 0.52 (κ-CN). Heritabilities for α_S1-CN%, κ-CN%, and β-CN% were similar and ranged from 0.63 to 0.69, whereas heritability of α_S2-CN%, γ-CN%, and β-LG% were 0.28, 0.18, and 0.34, respectively. Effects of CSN2-CSN3 haplotype and BLG genotype accounted for more than 80% of the genetic variance of α_S1-CN%, β-CN%, and κ-CN% and 50% of the genetic variance of β-LG%. The genetic correlations among the contents of CN fractions and between CN and whey protein fractions contents were generally low. When the data were adjusted for milk protein gene effects, the magnitude of the genetic correlations among the contents of milk protein fractions markedly increased, indicating that they undergo a common regulation. The proportion of β-CN in CN correlated negatively with κ-CN% (r = −0.44). The genetic relationships between CN and whey protein composition were trivial. Low milk pH correlated with favorable MCP. Genetically, contents and proportions of α_S1- and α_S2-CN in CN were positively correlated with RCT. The relative proportion of β-CN in CN exhibited a genetic correlation with RCT of −0.26. Both the content and the relative proportion of κ-CN in CN did not correlate with RCT. Weak curds were genetically associated with increased proportions in CN of α_S1- and α_S2-CN, decreased contents of β-CN and κ-CN, and decreased proportion of κ-CN in CN. Negligible effects on the estimated correlations between a₃₀ and κ-CN contents or proportion in CN were observed when the model accounted for milk protein gene effects. Increasing β-CN and κ-CN contents and relative proportions in CN and decreasing the content and proportions of α_S1-CN and α_S2-CN and milk pH through selective breeding exert favorable effects on MCP.     

Dietary Trans Fats Enhance Doxorubicin‐Induced Cardiotoxicity in Mice

This study investigated the combined effects of trans fat diet (TFD) and doxorubicin upon cardiac oxidative, inflammatory, and coagulatory stress. TFD increased trans fatty acid deposit in heart (P < 0.05), and decreased protein C and antithrombin‐III activities in circulation (P < 0.05). TFD plus doxorubicin treatment elevated activities of plasminogen activator inhibitor‐1, lactate dehydrogenase, and creatine phosphokinase (P < 0.05). This combination also raised xanthine oxidase activity, and enhanced cardiac levels of reactive oxygen species, interleukin (IL)‐6, IL‐10, tumor necrosis factor‐alpha, and monocyte chemoattractant protein‐1 than TFD or doxorubicin treatment alone (P < 0.05). TFD alone increased cardiac nuclear factor kappa B (NF‐κB) activity (P < 0.05), but failed to affect expression of NF‐κB and mitogen‐activated protein kinase (MAPK) (P > 0.05). Doxorubicin treatment alone augmented cardiac activity, mRNA expression, and protein production of NF‐κB and MAPK (P < 0.05). TFD plus doxorubicin treatment further upregulated cardiac expression of NF‐κB p65, p‐p38, and p‐ERK1/2 (P < 0.05). These findings suggest that TFD exacerbates doxorubicin‐induced cardiotoxicity.     

不同混凝剂处理高藻水效果对比研究

针对北方某水源有机物和藻类较高这一问题,进行了混凝、气浮,砂滤等常规工艺下FeCl_3和高效聚合铝盐(HPAC)混凝剂对浊度、有机物和藻类去除效果对比试验。结果表明,低投量下的Fe盐混凝剂去除TOC的效果优于低投量的Al盐,但高投量下却相反;从除藻效果分析,两种混凝剂差别不大。考虑混凝剂价格时,相同混凝剂费用下二者投量比(分别以FeCl 3和Al_2O_3计)为FeCl_3:HPAC=13:1,且在满足浊度出水水质情况下,最优Al盐费用少于Fe盐,但在以COD_(Mn)为控制指标时却相反。     

Evolution of number concentration of nano- particles undergoing Brownian coagulation in the transition regime

Evolution of number concentration of nanoparticles undergoing Brownian coagulation in the transition regime is studied theoretically and numerically.The results show that the curves of particle size distribution move toward the area with large particle diameters, the curve peak becomes lower and the range that particle diameters cover becomes wider as time elapses.In the process of coagulation the particles with small diameter disappear gradually and the particle size distribution remains a log-normal distribution.The change rate of the particle size distribution is more appreciable at the initial stage than that at the final stage.The initial Knudsen number has a significant effect on the coagulation rate which increases with decreasing the initial Knudsen number.The larger the initial geometric standard deviation is, the smaller the curve peak is, and the wider the area that curves cover is.The initial geometric standard deviation has a significant effect on the particle size distribution which can remain a self-preserving state when the initial geometric standard deviation is smaller than 2.With the increase of the diversity of initial particle size, the particle size distribution does not obey the log-normal distribution any more as time elapses.     

强化混凝超滤组合工艺对有机污染物去除效能的研究

为了进一步提高水质处理效果,采用强化混凝超滤的组合工艺对湖水进行处理,考察该组合工艺对有机物的去除效能,及影响有机物去除效能的因素。试验结果表明:①强化混凝超滤组合工艺对原水浊度的去除效果较好,对TOC和UV254的去除效果也明显优于传统水处理工艺;②原水中UV254含量的波动,对UV254的去除率和滤后水UV254含量影响并不大。原水中TOC含量的波动,对TOC的去除率有很大的影响,对滤后水TOC含量的影响并不大。TOC的去除率普遍高于UV254的去除率;③根据原水和滤后水SUVA值的变化发现,强化混凝超滤组合工艺对亲水性有机物的去除率大于该工艺对疏水性有机物的去除率。在一定范围内,pH的变化对TOC和UV254去除率变化趋势相反。     

Fenton氧化/强化混凝法预处理槟榔废水的试验研究

采用Fenton氧化/强化混凝法对湖南某食用槟榔生产排放的废水进行预处理实验研究.实验结果表明：采用Fenton试剂,在初始pH值为5.0,H202投加量为247.5 g/L,Fe2投加量为1.40 g/L,反应时间为2h的条件下,CODcr去除率达到88.56％,色度去除率达到83.33％.继续采用10％的氢氧化钠对上清液进行强化混凝处理,在调节pH为9.0,反应时间为10 min的条件下,出水的CODcr可降至1980.0 mg/L,色度可降至20倍,颜色清澈,极大的消减了污染负荷,达到了良好的预处理效果.     

去除景观湖泊中膜状浮泥的试验

城市景观湖泊中漂在水面上的浮泥不仅影响水体景观,而且还阻碍空气中的氧向水中传输,影响水质。采用化学混凝法对其进行处理,结果表明：浮泥层主要由微小泥粒和少量的其它碎小杂物组成;浮泥Ⅰ采用硫酸铝、浮泥Ⅱ采用聚铝为混凝剂时,可有效降低水中的浊度、色度和高锰酸钾指数;但对浮泥Ⅱ的去除效果不如浮泥Ⅰ,原因是其中的藻类较多,影响了微小泥粒的絮凝。并对具体操作上的问题进行了讨论。     

聚硅酸铁的碱解实验及混凝效能研究

采用共聚法制备不同Si/Fe比的聚硅酸铁(PSF)混凝剂(PSF0.5、PSF3分别指Si/Fe摩尔比为0.5、3),并对PSF进行碱解实验以及PSF对松花江水、哈尔滨市南岗区生活污水的混凝实验。结果表明,通过碱解实验可以得到有关混凝剂内部形态变化以及各原料反应过程的一些辅助信息。碱解实验可以进一步较准确验证PSF的反应机制:共聚初期,低Si/Fe比生成以Si-O-Fe-O-Fe-O-Si键络合的物种,随共聚时间的增加可能导致易断裂的Fe-O-Fe键断裂;而高Si/Fe比在共聚初期,铁和聚硅酸还没有络合或络合很少,随共聚时间的增加,主要生成以Si-O-Fe-O-Si-O-Si键络合的物种。Fe-O-Fe键稳定性比Si-O-Fe或Si-O-Si键差。综合浊度、UV254和COD的去除效果,PSF0.5、PSF3对松花江水的最佳投药量分别为8.5mg/L、10.5mg/L,对哈尔滨市南岗区生活污水的最佳投药量分别为70mg/L、100mg/L。PSF3的除浊再稳投药量低于PSF0.5,而PSF0.5去除UV254、COD的再稳投药量却低于PSF3。     

优选混凝剂及助凝剂处理低温低浊水的方法

文章研究了低温低浊水混凝剂及助凝剂的优化选择,考察了浊度、COD M n、氨氮等水质特征,分析了低温低浊水的处理效果。结果表明,混凝剂和助凝剂投加量增大,上清液中浊度、COD去除率不断提高。在PAFC用量为12 mg/L,活化硅酸用量为0.12 mg/L条件下,浊度、COD去除率分别达到最大值98.3%和87%,剩余浊度和剩余COD M n分别为0.21 NTU、0.64 mg/L。而PAC＋PAM表现出更好的除氨氮效果,剩余氨氮为0.07 mg/L。     

饮用水混凝除磷技术试验研究

通过混凝实验,观察混凝除磷与除浊的关系,考察混凝剂品种、pH对混凝除磷效果的影响,以及混凝对水中不同形态磷的去除效果.研究高锰酸钾复合药剂(PPC)及聚丙烯酰胺(PAM)的助凝除磷效果.结果表明:强化混凝可以有效提高混凝除磷的效果;聚铁混凝除磷效果明显好于聚铝和聚铝铁;3种混凝剂除磷最佳pH分别为:聚铁7.5,聚铝6.5,聚铝铁6.0;溶解性磷的去除总体上来说更加困难,但是当混凝剂投量增加到一定水平,溶解性磷也能得到有效去除;PPC与PAM均具有一定的助凝除磷效果,但PAM的用量和投加时间必须很好控制.