Suspension of the calcium-sensitive human beta-caseins by human kappa-casein

The beta-casein (CN) fraction of human milk exists as a single protein entity phosphorylated at various levels from zero to five (beta-CN-0P to beta-CN-5P). Since the beta-CN fraction is precipitated by the calcium ions in milk, a stabilizing protein is needed to form a suspension of casein micelles for ready ingestion by the infant. That stabilization is known to be carried out by kappa-CN but it is also thought possible that the 0P and 1P beta-CN moieties may play a role. To examine the effects of different phosphorylation levels, 10 mM CaCl2 was added to each of the purified proteins phosphorylated (P) at different levels. Without kappa-CN, precipitation of the different beta-CN forms varied from 78 to 99%. Human kappa-CN was then added to each to give kappa/beta molar ratios varying from 0.01 to 0.25. Some stabilization was observed even at the lowest ratio and more than 90% of the protein was suspended in all cases at the highest ratio. Interaction of low levels of kappa-CN with the different forms of beta-CN to create a suspension was somewhat dependent on the phosphorylation level and the possibility of forming intra- or intermolecular Ca2+ bridges or cross-links. Similar ratios of the beta-CN-4P to either the 0P or 1P form and of the 2P to the 1P form showed that neither the 0P nor 1P form had any stabilizing ability. In fact, coprecipitation occurred so that with either the 4P or 2P forms present, higher percentages of the 0P and 1P forms precipitated.     

富硒食品的研究进展与展望

目的：从海洋样品中分离、筛选及鉴定具有富硒功能的酵母菌,并探究发酵工艺对菌株富硒效果的影响。方法：结合耐硒法和红硒法从海南省东寨港红树林中分离纯化筛选出具有高富硒能力的海洋源微生物,通过形态学、生理生化和分子生物学方法对菌株进行鉴定。采用3,3'-二氨基联苯胺盐酸盐法对菌株的硒含量进行定量测定,最后经单因素实验对菌株的发酵工艺进行优化。结果：从海洋源样品中筛选鉴定出一株安全的具有富硒功能的发酵性拉茜斯酵母Lachancea fermentati HN-10,该酵母在接种量为5%、初始pH为6、发酵温度为22 ℃、发酵转速为180 r/min、发酵时间为48 h、硒添加量为20 μg/mL的最优发酵工艺下生物量可达4.52 g/L,富硒量可达1.57 mg/g,对应的硒转化率可达35.43%。结论：海洋源L. fermentati HN-10具有潜在的富硒食品开发应用前景。

     

甘油三脂与人体健康

甘油三脂也称中性脂肪,对人体有重要作用,但是甘油三脂过量也会给人体健康带来很多危害。本文首先介绍了甘油三脂3个主要生理功能,即重要的能源、构成人体组织和调节身体机能;其次说明了甘油三脂主要会造成肥胖症、痤疮和心血管疾病;最后提出主要可从3个方面来控制甘油三脂的水平,即均衡饮食、适当的运动和控制饮酒。     

Ethics of human testing

What should one do, and why? Anyone asking such questions - and everyone does so hundreds of times each day - is concerned with ethics. Product development and testing raise many ethical questions. Particularly since the rise of ‘green consumerism’, these are of increasing concern to people outside the cosmetics industry, and so should be of interest to those inside it. The major problem seems to be that of reaching agreement on moral and ethical issues. Overcoming this problem involves investigating what is meant by ‘ethics’, and how decisions depend not on facts but on ‘facts-as-perceived’. These in turn depend on many factors, with one's philosophy being the most fundamental. The range of philosophical options is reviewed and it is proposed that wider discussion is the only just way to achieve agreement. Yet some things are not negotiable. There are certain key moral concepts in terms of which discussion must take place for it to be relevant. In ethics of human testing, ‘respect for others’, that is, avoiding exploitation, is the principal one. Some synthesis of the key moral concepts like that of Immanuel Kant is therefore recommended as the soundest and most widely acceptable basis for the necessary discussion. Defining the responsible use of human subjects covers a range of issues, moral, historical, legal and professional. For example, there may be ethical difficulties in deliberate damage induction as in SPF and irritancy testing. But above all, to avoid exploitation, there is a moral and also a legal requirement that subjects are truly volunteers. This is the basis of the concept of ‘informed consent’, required but not generally explained in current professional codes of practice. It is unjustified to exploit those who may be under duress, such as ‘in-house volunteers' and those with low incomes. Hence in conclusion, criteria for obtaining valid informed consent are briefly reviewed. By considering issues such as these, we can help ensure that cosmetic scientists are true professionals, that is, those who recognise and are concerned with the ethical basis of their work.     

钙与人体健康

从钙的生理功能、钙在人体内的调节、代谢等方面，叙述钙与人体健康的关系，旨在说明人们在膳食中摄入适量钙是保证人体健康所必要的，并为推动人们改变膳食结构，以及南平市农业结构的调整，提供一定的理论基础。     

Soups in human nutrition

The article gives information about the soups traditionally used by the population of Russia. A classification of soups, their nutrients and energy content, as well as the contribution of soups to daily nutrient consumption of the population are presented. Taking into account results of epidemiological researches of dietary the most popular types of first lunch dishes (soups) in the population of Russia were found out.     

维生素与人体健康

以前，我们从市场上只能零星购买到种数不多的几种维生素产品。然而，现在的市场，各种维生素保健品成千上万，而且数量还在逐年递增，让我们感到很迷惑，不知道究竟需要补充哪一种营养物质，才能更有益于身体的健康。 据美国国家科学院食品与营养学会（ＡＦＮＢ）建议，食谱中维生素的推荐量（ＲＤＡ），应该依据人年龄大小的不同而不同，才能保持最佳的身体状态。根据这一提议，美国食品与药品管理委员会对维生素的每日用量做了规定。购买时，瓶子和食品标签上都备有详细说明。 维生素在人体健康中所起的作用不可替代。然而调查表明，即使…     

Available human feeder cells for the maintenance of human embryonic stem cells

Mouse embryonic fibroblasts (MEFs) have been previously used as feeder cells to support the growth of human embryonic stem cells (hESCs). In this study, human adult uterine endometrial cells (hUECs), human adult breast parenchymal cells (hBPCs) and embryonic fibroblasts (hEFs) were tested as feeder cells for supporting the growth of hESCs to prevent the possibility of contamination from animal feeder cells. Cultured hUECs, hBPCs and hEFs were mitotically inactivated and then plated. hESCs (Miz-hES1, NIH registered) initially established on mouse feeder layers were transferred onto each human feeder layer and split every 5 days. The morphology, expression of specific markers and differentiation capacity of hESCs adapted on each human feeder layer were examined. On hUEC, hBPC and hEF feeder layers, hESCs proliferated for more than 90, 50 and 80 passages respectively. Human feeder-based hESCs were positive for stage-specific embryonic antigen (SSEA)-3 and -4, and Apase; they also showed similar differentiation capacity to MEF-based hESCs, as assessed by the formation of teratomas and expression of tissue-specific markers. However, hESCs cultured on hUEC and hEF feeders were slightly thinner and flatter than MEF- or hBPC-based hESCs. Our results suggest that, like MEF feeder layers, human feeder layers can support the proliferation of hESCs without differentiation. Human feeder cells have the advantage of supporting more passages than when MEFs are used as feeder cells, because hESCs can be uniformly maintained in the undifferentiated stage until they pass through senescence. hESCs established and/or maintained under stable xeno-free culture conditions will be helpful to cell-based therapy.     

基于人乳脂肪组成的酶法人乳脂肪替代物的构建

为了开发新型高相似性人乳脂肪替代物,依据中国人乳脂肪的脂肪酸组成和甘油三酯结构,以巴沙鱼油、樟树籽仁油、亚麻籽油、微生物油(富含ARA)及DHA藻油(质量比为153.81∶15.16∶62.33∶7.89∶10.81)为原料油脂,以固定化脂肪酶Lipozyme RM为催化剂,在60℃下酯交换反应8 h制备人乳脂肪替代物,测定其脂肪酸、sn-2位脂肪酸及甘油三酯组成及含量,分析其红外光谱图、熔融性质、结晶性质及流变学性能。结果表明,构建的人乳脂肪替代物中链脂肪酸含量为12%、亚油酸和亚麻酸总含量为19.53%且比例约为1∶1.5,ARA含量为1.17%,DHA含量为1.11%,其sn-2位富含棕榈酸(43.10%),结构甘油三酯含量高(58.75%),无反式脂肪酸生成,熔融温度低于人体温度且在20℃下仍能保持18.7%的固体脂肪含量,结晶形态细腻且流变性能优异。制备的人乳脂肪替代物具有应用于婴幼儿配方奶粉、婴幼儿米糊和婴幼儿饼干等各种婴幼儿食品的潜力。     

金刚石与人类社会(下)

详细介绍了天然金刚石的发现、特性、鉴别方法和应用范围,论述了金刚石粉体、单晶金刚石、金刚石膜和聚晶金刚石的人工合成方法和应用情况。     

Chlorinated phenols in human milk

The paper deals with the contamination of human milk with chlorinated phenols. The average and median concentrations of the chlorophenols investigated ranged from 0.75 to 9.74 g.kg^–1 and from being not detectable to 5.62 g.kg^–1, respectively, for the different compounds. The highest average and median levels were found for pentachlorophenol and 2,4,5-trichlorophenol. The concentrations determined were below the permissible levels.     

金刚石与人类社会(上)

详细介绍了天然金刚石的发现、特性、鉴别方法和应用范围,论述了金刚石粉体、单晶金刚石、金刚石膜和聚晶金刚石的人工合成方法和应用情况。     

A human gastric simulator (HGS) to study food digestion in human stomach

The objective of this study was to develop an in vitro stomach model, the Human Gastric Simulator (HGS), for studying gastric digestion of foods. The HGS is designed in such a way as to simulate the continuous peristaltic movement of stomach walls, with similar amplitude and frequency of contraction forces as reported in vivo. The HGS mainly consists of a latex vessel, simulating the stomach chamber, and a series of rollers secured on belts that are driven by motor and pulleys to create a continuous contraction of the latex wall. It also incorporates gastric secretion, emptying systems, and temperature control that enable accurate simulation of dynamic digestion process for detailed investigation of the changes in the physical chemical properties of ingested foods. The simulated gastric contraction force demonstrates a similar pattern as in vivo stomach forces. The precise control of gastric secretion and emptying and the adjustable mechanical forces in the HGS provide a useful tool to study transformation of food constituents under simulated physiological conditions.     

绿色食品与人体健康

随着工业化和现代化的发展,环境污染问题日益突出,尤其是通过食物链的污染更直接威胁着人类的健康。据华盛顿报导,因环境污染每年死亡人数高达１７００万之多,贫困地区５个儿童中有一个活不到５岁。工业发达地区的癌症、心血管病、哮喘病日益增多。癌症仍居死因的首位,我国患癌人数达１６０万／年,死亡人数达１３０万。癌症诱因的９０％是环境因素,其中通过食物进入人体诱发的比例,高达６０％之多。因此,防止食品污染是保障人体健康的当务之急,而发展绿色食品是防止食品污染、截毒保健的重要途径。 一、食品污染物质与危害 当前最…