水溶性豆渣酸性多糖对RAW264.7细胞的免疫调节作用及其机制

研究水溶性豆渣多糖(water-soluble soybean polysaccharides,SSPS)对RAW264.7细胞的免疫调节作用.首先,以NO浓度为指标,明确SSPS、水溶性豆渣酸性多糖A1(soluble soybean acidic polysaccharide A1,SSPS-A1)和水溶性豆渣酸性...     

魔芋葡甘聚糖/κ-卡拉胶复合凝胶制备条件的优化

为了优化κ-卡拉胶-魔芋葡甘聚糖复合凝胶制备条件,以期改善以魔芋葡甘聚糖为原料的复合凝胶质产品,使其具备较佳的特性黏度。本研究以κ-卡拉胶(KC)、魔芋葡甘聚糖(KGM)为实验对象,以复合胶液黏度作为指标,在单因素实验的基础上,通过建立三因素三水平响应面优化设计实验,对水浴温度、搅拌时间及底物配比工艺参数进行优化分析。结果表明:水浴温度、搅拌时间及底物配比是复合胶液黏度的显著影响因子(p<0.05),各因素间交互作用对复合胶液的黏度影响效果显著(p<0.05);当水浴温度为76 ℃,搅拌时间为1.5 h及底物配比(KGM:KC)为5:3时,实验所得复合胶液黏度值为68.87 Pa·s,与模型预测值69.1397 Pa·s接近,误差为0.39%<1%,说明经过优化所得的最佳工艺参数可靠合理。     

κ-卡拉胶与亚麻籽胶复配对成型火腿品质的影响

以成型火腿为研究对象,通过分析保水性(加压失水率、蒸煮损失率)、质构(硬度、内聚性、弹性、咀嚼度、胶着性)、色差及感官指标,研究不同添加量κ-卡拉胶(0.1％、0.2％、0.3％、0.4％、0.5％)对成型火腿品质的影响,以不添加κ-卡拉胶的成型火腿为对照,筛选出κ-卡拉胶的适宜添加量;将κ-卡拉胶和亚麻籽胶按质量比1...     

酪蛋白三种组分的酶解特性研究

酪蛋白由3种成分组成,即αs-酪蛋白,β-酪蛋白,κ-酪蛋白。本文对酪蛋白的三种组分进行分离,用SDSPAGE电泳进行检测,得到相对纯度分别为89.50%、96.51%、90.99%。酪蛋白三种组分用胰蛋白酶进行酶解,对酶解物的水解度和粒度分布进行测定,酶解物的粒度分布用激光粒度分析仪测定。得到的结论是:在三种组分的酶解物中,αs-酪蛋白酶解物的水解度最高,随着酶解时间的延长,αs-酪蛋白酶解物中的粒径越来越小。β-酪蛋白酶解物在前12h水解度增加最少,β-酪蛋白酶解物在前6h粒度变化也不明显。κ-酪蛋白酶解物的水解度以线性形势增加,且κ-酪蛋白酶解10min内,粒径变化明显。      

Formation of aluminium carbide by cast iron and liquid aluminium interaction

Abstract

Aluminium carbide (Al₄C₃) has been identified in ex service and laboratory test specimens of cast irons exposed to liquid aluminium. In cast iron/aluminium couples, the formation of Al₄C₃ and κ-Fe₃AlC was confirmed for the first time. The growth kinetics of Al₄C₃ were parabolic with an activation energy 145±23 kJ mol^?1 (1023–1223 K), which is consistent with the reported activation energy for growth in graphite/liquid aluminium couples. The aim of this work is to shed light upon the origin and growth of Al₄C₃ in cast iron/liquid aluminium couples in the temperature range of 1023–1223 K.     

Effects of aluminum content on cracking phenomenon occurring during cold rolling of three ferrite-based lightweight steel

The effects of Al content on cracking phenomena occurring during cold rolling of ferritic lightweight steels were investigated in relation to microstructural modification including κ-carbides. Three steels were fabricated, varying the Al content between 4 and 6 wt.%, and the center and edge areas of steel sheets containing 6 wt.% Al were cracked during cold rolling. The three steels were composed of ferrite grains and κ-carbides in a banded shape, and the overall volume fraction of κ-carbide increased with increasing Al content. The shape of lamellar κ-carbides inside κ-carbide bands was changed from short and thin to long and thick. Microstructural observation of the deformed region of fractured tensile specimens revealed that deformation bands were homogeneously formed in wide areas of ferrite matrix in the steels containing 4–5 wt.% Al, and κ-carbide bands and boundary κ-carbides were hardly cracked. In the steel containing 6 wt.% Al, however, microcracks were initiated at grain boundary κ-carbides and long lamellar κ-carbides inside κ-carbide bands. They led to the center or edge cracking during cold rolling. To prevent or minimize cracking, it was necessary to avoid the lengthening or thickening of lamellar κ-carbides. Therefore, it was recommended that the steels should be rapidly cooled from the finish rolling temperature to the coiling temperature through the formation temperature of κ-carbide.     

蛋白酶体抑制剂MG132对肿瘤恶病质的作用及其分子机制

目的探讨蛋白酶体抑制剂MG132对肿瘤恶病质的作用及其可能的分子机制。方法经小鼠腋窝皮下注射结肠腺癌C26细胞,建立肿瘤恶病质模型,并设正常对照组(HC组)。将模型小鼠分为肿瘤恶病质组(CC组)和MG132治疗组(MG组),待小鼠进入恶病质状态后,CC组小鼠经腹腔注射0.1 ml生理盐水,MG组小鼠经腹腔注射0.1 mg/kg的MG132,7 d后处死小鼠,称量小鼠肿瘤、左侧腓肠肌和附睾脂肪的重量,测量腓肠肌纤维横切面积,ELISA法检测血清中炎性因子TNF-α和IL-6的水平,RT-PCR及Western blot法检测腓肠肌中IKBa、P65、MuRF1和MAFbx基因mRNA的转录水平及蛋白的表达水平。结果与CC组相比,MG组小鼠腓肠肌和附睾脂肪组织的重量分别增加了31.6%和39.5%(P<0.05),腓肠肌纤维横切面积增加了36.1%(P<0.05);血清中TNF-α和IL-6的水平分别降低了20.9%和42.0%(P<0.05);腓肠肌组织IKBa基因mRNA的转录水平和蛋白表达水平分别升高了132.7%和56.5%(P<0.05),MuRF1基因mRNA的转录水平和蛋白表达水平分别降低了70.1%和42.6%(P<0.05),MAFbx基因mRNA的转录水平和蛋白表达水平分别降低了76.8%和47.3%(P<0.05),P65基因mRNA的转录水平和蛋白表达水平分别降低了59.1%和53.1%(P<0.05)。结论 MG132改善肿瘤恶病质的分子机制可能与抑制NF-κB途径及MuRF1和MAFbx的表达、抑制炎症反应及肿瘤生长有关。     

κ-Casein Macropeptides from Cheese Whey: Physicochemical,Biological, Nutritional,and Technological Features for Possible Uses

Abstract

κ-Casein macropeptide (CMP), one of the components of whey, is produced during cheese making. Whey production has grown enormously in the last three decades and will continue to grow, along with cheese production. There is an increased interest in research for new applications of food industry by-products in order to avoid their extensive elimination and negative environmental implications. In this respect, CMP has been the focus of extensive scientific research that has proven its value as a functional and bioactive peptide, as well as a source of biologically active peptides. This article evaluates the possibilities and future perspectives of the use of CMP and related peptides obtained from cheese whey from different ruminant species. Physicochemical, technological, biological, and nutritional aspects are considered, and processes for analysis, fractionation, and separation are reviewed. The objective is to help to promote further exploitation of cheese industry coproducts for the preparation of high added-value ingredients to be included in the composition of nutraceuticals or functional food products.     

Research progress on polymer-inorganic thermoelectric nanocomposite materials

A thermoelectric (TE) material is a material where a potential difference is generated as a result of a temperature difference or the corollary of this where a temperature difference is generated when a voltage is applied. These phenomena can be used to generate electricity and/or control temperature. Traditionally, thermoelectric materials are inorganic semiconductors which have been limited in their application by low efficiency and high cost. Since the 1990s, both theoretical and experimental studies have shown that low-dimensional TE materials, such as superlattices and nanowires, can enhance the value of the TE figure of merit (ZT) which is an indicator of TE thermodynamic efficiency. To date it has not been feasible to apply these materials in large-scale energy-conversion processes because of limitations in both their heat transfer efficiency and cost. When compared to inorganic materials, organic conducting polymers possess some unique features, such as low density, low cost, low thermal conductivity, easy synthesis and versatile processability and their use in preparing polymer-inorganic TE nanocomposites appears to have great potential for producing relatively low cost and high-performance TE materials. Recently, an increasing number of studies have reported on polymeric and polymer-inorganic TE nanocomposite materials. The purpose of this paper is to review the research progress on the conducting polymers and their corresponding TE nanocomposites. Its main focus is the TE nanocomposites based on conducting polymers such as polyaniline (PANI), polythiophene (PTH), poly (3, 4-ethylenedioxythiophene): poly (styrenesulfonate) (PEDOT:PSS), as well as other polymers such as polyacetylene (PA), polypyrrole (PPY), polycarbazoles (PC) and polyphenylenevinylene (PPV). Typically, polymer-inorganic TE nanocomposites are produced by physical mixing, solution mixing and in situ polymerization. The key factors that limit the use of these polymers and their polymer-inorganic TE nanocomposites as TE materials are their low ZT values. More recent developments designed to overcome the limitation including, for example, the use of carbon nanotubes and graphenes and the use of computational modelling to accelerate the selection of suitable pairs of conductive polymer and inorganic TE materials to achieve best possible nanocomposites are reviewed.