Effect of fining and filtration on the haze formation in bayberry (Myrica rubra Sieb. et Zucc.) juice

Bayberry juice was fined with the methods of xanthan/chitosan (XC) or gelatin/bentonite (GB), and then filtered with diatomaceous earth filtration (DF) or ultrafiltration (UF, MWCO 100 kDa). Their effects on juice haze formation were investigated. The XC fining method was more effective than the GB method in removal of the total monomeric anthocyanin, total phenolics, and protein, with less haze formed in the XC fined juice. The DF reduced 2-5% of the total phenolics and 21-23% of protein, while UF reduced 19-24% of the total phenolics and 34-38% of protein, respectively. The results showed that fining and then UF can reduce but cannot eliminate haze formation in bayberry juice. The storage temperature was a critical factor affecting haze formation, and the juice was more stable when stored at lower temperature (4 degrees C).     

木质包装中黄斑星天牛微波处理初探

为了探索微波处理作为木质包装替代处理方法的可能性,对不同规格和含水量的杨树木块进行微波处理试验,结果表明:频率为2450MHz的微波能够穿透厚度为10cm的杨树木材;当微波功率为900W时,规格为10cm×10cm×10cm和10cm×10cm×2.5cm的新木块中黄斑星天牛(Anoplophora nobolis)幼虫完全死亡所需时间分别为5min和2min;而干木块中则仅需3min和30s.对微波处理引起木材温度变化和水分损失以及天牛幼虫的水分损失进行了初步研究.     

抓住机遇乘势而上进一步提升蔬菜产业发展水平———河北省蔬菜产业调研报告

近年来,河北省利用独有的地理自然条件和优势打造了一批具有鲜明特色的蔬菜优势生产区域,蔬菜产业水平进一步提升。2011 年全省蔬菜播种面积126.33 万hm2,总产量达7 898 万t,蔬菜产业发展成效显著。     

Characterization of isoflavones and their conjugates in female rat urine using LC/MS/MS

Isoflavone phytoestrogens found in soybeans are the most widely studied phytochemicals in human diets and soy infant formulas. The health benefits of the isoflavones daidzein and genistein have been reported, and concerns about potential adverse effects have also been raised. However, the results of direct analysis of isoflavones and their metabolites in biological fluids after consumption of soy-containing diets are scarce. This study describes an LC/MS/MS method for the analysis of isoflavones and their metabolites in the urine of female rats fed diets made with soy protein isolate. Five isoflavones (daidzein, genistein, glycitein, dihydrodaidzein, and O-desmethylangolensin) were identified by comparison with authentic standards. Seventeen conjugates of isoflavones were characterized in the urine, the most unusual being genistein 5-glucuronide and four glucuronide conjugates of reductive metabolites of daidzein. The application of LC/MS/MS to analyze isoflavone metabolites is simple and sensitive, and appears to be an excellent method for determining the bioavailability and metabolism of food phytochemistry.     

行间耕播机弹性可覆土镇压轮性能有限元仿真分析及试验

为提高播种机的播种及镇压性能,解决播种作业中覆土后即时镇压的难题,结合橡胶类材料的变形理论与轮胎力学的研究基础,建立基于种沟沟型的理论模型,并设计出一种具有覆土功能的弹性镇压轮,镇压轮横截面由顶端连通的两个腔室组成,通过镇压轮侧缘与种沟接触产生的挤压力以同时实现覆土和镇压作业。利用ABAQUS软件对镇压轮进行有限元仿真分析,考察其覆土及镇压性能,通过有限元仿真分析证实该模型可行有效。通过与双圆盘覆土器和传统橡胶镇压轮的田间对比试验测得,该文所设计的弹性可覆土镇压轮作业后种子平均覆土深度为34 mm,变异系数为15.68%,镇压后种子上方距离地表5 cm的土壤紧实度为33.5 k Pa,变异系数为13.97%,应用双圆盘覆土器和传统橡胶镇压轮作业后种子平均覆土深度为35.3 mm,变异系数为17.51%,镇压后种子上方距离地表5 cm的土壤紧实度为26.5 k Pa,变异系数为15.32%,田间对比试验证实弹性可覆土镇压轮和双圆盘覆土器均可满足玉米播种作业对覆土深度的要求,但弹性可覆土镇压轮对土壤的镇压强度大于传统橡胶镇压轮,同时由覆土深度变异系数和镇压强度变异系数可以看出,弹性可覆土镇压轮在作业过程中的覆土深度稳定性和镇压强度稳定性均优于双圆盘覆土器和传统橡胶镇压轮。     

农用化学物质对土壤脲酶活性的影响

通过对呋喃丹、铁灭克、天王星3种农药对土壤脲酶活性的抑制性进行试验 ,分析了不同农药用量、培养时间、尿素用量及外加不同 pH值缓冲溶液的情况下对脲酶活性的影响。结果表明 ,3种农药在不同情况下对脲酶活性均有不同程度的抑制作用 ,也证明了在本地区特有的农业环境条件下 ,农用化学物质可能会影响和破坏农业生态环境     

大棚春季番茄-秋季辣椒高效避病栽培模式

春季种植番茄,黄化曲叶病毒的发生几率低,秋季种植辣椒,避开番茄感染黄化曲叶病毒的风险,大棚春季番茄一秋季辣椒的种植模式效益可观。     

Role of histone H3 lysine 27 methylation in X inactivation

The Polycomb group (PcG) protein Eed is implicated in regulation of imprinted X-chromosome inactivation in extraembryonic cells but not of random X inactivation in embryonic cells. The Drosophila homolog of the Eed-Ezh2 PcG protein complex achieves gene silencing through methylation of histone H3 on lysine 27 (H3-K27), which suggests a role for H3-K27 methylation in imprinted X inactivation. Here we demonstrate that transient recruitment of the Eed-Ezh2 complex to the inactive X chromosome (Xi) occurs during initiation of X inactivation in both extraembryonic and embryonic cells and is accompanied by H3-K27 methylation. Recruitment of the complex and methylation on the Xi depend on Xist RNA but are independent of its silencing function. Together, our results suggest a role for Eed-Ezh2-mediated H3-K27 methylation during initiation of both imprinted and random X inactivation and demonstrate that H3-K27 methylation is not sufficient for silencing of the Xi.     

Suppressive effect of saturated acyl L-ascorbate on the oxidation of linoleic acid encapsulated with maltodextrin or gum arabic by spray-drying

6-O-Palmitoyl L-ascorbate was added to linoleic acid at various molar ratios of the ascorbate to the acid, the mixtures were emulsified with a maltodextrin or gum arabic solution, and the emulsions were spray-dried to produce microcapsules. At higher molar ratios, the oil droplets in the emulsions were smaller, and the oxidative stabilities of the encapsulated linoleic acid were higher for both the maltodextrin- and gum arabic-based microcapsules. 6-O-Capryloyl, caproyl, and lauroyl L-ascorbates, which were synthesized through lipase-catalyzed condensation in acetone, were also used for the microencapsulation of linoleic acid. Except for capryloyl L-ascorbate, the addition of a saturated acyl ascorbate, especially caproyl ascorbate, to linoleic acid was effective for preparing oil droplets of small particle diameter and for suppressing the oxidation of the encapsulated linoleic acid.     

沽源县脱毒种薯繁育体系建设的现状及发展前景

沽源县位于河北省西北部 ,是河北省重要的马铃薯种薯和商品薯生产基地之一。县政府将马铃薯种薯业的发展列为当地经济发展的一项重大项目。因此 ,研究该地区马铃薯的繁育体系建设对当地经济的发展有着重要的意义。沽源县马铃薯生产技术主要依托中国农科院及张家口坝下、坝上农科所。资金主要来源于省、市、县财政投资 5 0 0万元 ,并广泛地吸收张家口燕通公司投资 110 0万元 ,在沽源县成立了由中国农科院、沽源县政府、燕通公司三方控股的中农源通马铃薯股份有限公司。组建了 15 0 0ｍ2 的现代化育苗温室及办公大楼、科研楼。在全县各乡镇建…