Macrostructural changes of polymer replicated open cell cordierite based foams upon sintering

Abstract

The goal of this work was to clarify the macrostructural changes that take place upon sintering of open cell cordierite based foams. A methodology, based on optical image analysis, was developed to assess the structure of open-cell foams, which allowed evaluating the macrostructure of both cordierite based foams obtained by the replication process and their polymeric templates. The parameters used to describe the structures were the size of the cell and the window, the window shape factor, the strut thickness and the volume fraction of the material. The experimental evidence gathered opened the way to understand the physical/chemical transformations involved in the polymer burnout and the ceramic sintering processes, as well as their influence on the ceramic final structure. The observed trends provide guidance for tailoring 'replicated' cordierite based foams, in view of the required application.     

Evaluation of aglianico grape skin and seed polyphenol astringency by SDS–PAGE electrophoresis of salivary proteins after the binding reaction

SDS–PAGE electrophoresis and densitometry analysis were carried out to evaluate the reactivity of Aglianico red grape skin and seed polyphenols with human salivary proteins in order to find a method able to assess their astringency. Analysis of the supernatant obtained after a tannin/human salivary protein binding assay and sensorial analysis showed that four proteins, lactoferrin, PRPbg1, PRPbg2 and α-amylase, were the proteins best able to distinguish tannin solutions characterised by different levels of astringency.     

桑蚕丝蛋白的聚丙烯酰胺凝胶电泳研究 Ⅰ.丝蛋白的非解离和解离系统电泳

本文用聚丙烯酰胺凝脉电泳法(PAGE),对桑蚕绢丝腺蛋白和茧丝蛋白进行了研究。测定了主要谱带的分子量,并进行了讨论。     

同位素示踪法测定~(125)I-NGF在小鼠体内的血药浓度变化

本文涉及应用Idogn法对神经生长因子(NGF)进行125I标记并利用同位素示踪与电泳分离相结合的方法测定125I-NGF在小鼠体内的血药浓度与时间变化关系。结果显示,静脉注射125I-NGF在小鼠体内的代谢规律符合二房室开放模型。分布相半衰期为0.13h,消除相半衰期为3.68h,125I-NGF在小鼠体内分布和消除均较快,清除率为0.125L/h/Kg,表观分布容积为0.697L/kg,曲线所围面积为16.01μg.h/L。     

Changes in corrosion rates in atmospheres with changing corrosivity

Abstract

This paper presents a study on the atmospheric corrosion of carbon steels, zinc, copper and aluminium in the industrial atmosphere. Trends representative for Central Europe are evaluated on the results for the Czech test site Kopisty. The climatic data and levels of pollutants, namely SO₂, have been measured, collected and analysed over 25 years. The corrosion rate of structural metals is significantly affected by SO₂ and the metals quickly react to the decrease of SO₂. The corrosion of both newly exposed metals and surfaces formerly exposed to polluted environments slowed when SO₂ pollution in the atmosphere was reduced. The study does not reflect the effects in atmospheric corrosion systems with dominating chloride influences (marine and marine–industrial atmospheres). The chemical composition and morphology of the corrosion product layers of zinc, copper and aluminium are presented and compared. The comparison of the corrosion rates and corrosion product compositions of zinc after 1, 20 and 100 years of exposure is presented.     

Stability of sunflower 2S albumins and LTP to physiologically relevant in vitro gastrointestinal digestion

In order for a protein to elicit a systemic allergic response it must reach the circulatory system through the intestinal mucosa as a sufficiently large fragment with adequate structural integrity. Sunflower LTP and 2S albumins (SFA8 and three mixed fractions of Alb1 and Alb2) were digested in simulated gastric fluid (SGF) for 2 h and the conditions were then changed to mimic the intestinal environment for a further 2 h digestion. The effects of phosphatidylcholine (PC) and emulsification on the digestibility of the proteins were investigated. PC protected all of the proteins studied against both gastric and intestinal digestive enzymes but to different extents. Emulsification of SFA8 resulted in strong protection against digestion, which was further enhanced by the presence of PC in the SGF. These results highlight the importance of considering real food structures such as emulsified systems and also the gastrointestinal environment that proteins are exposed to once consumed when assessing allergenicity.     

Isolation,fractionation, and some chemical studies on Kleinhovia hospita Linn. seed protein

Protein was extracted from the seeds of Kleinhovia hospita Linn., which is being a nonconventional source. Extraction of K. hospita seed protein at various pH values in aqueous solution and at pH 7, different salt concentrations were done. Fractionation of protein from seeds was performed to separate albumin, globulin, prolamin, and glutelin. The amino acid compositions of total protein isolate (TPI) and the fractions were determined. A total of 15 amino acids were identified including 9 essential amino acids. Gel filtration by Sephadex G-100 revealed the presence of three components in the TPI. Sodium dodecyl sulfate–polyacrylamide gel electrophoresis analysis of TPI and fractions showed different polypeptide bands having molecular weights ranging from 12 to 42 kDa approximately. Scanning electron microscopic study of TPI and fractions revealed the surface topology of the protein.     

Water‐soluble protein molecular weight distribution and effects on wheat malt quality during malting

The content and the molecular weight distribution of wheat water‐soluble proteins during malting were determined. Also, the relationships between wheat malt characteristics and water‐soluble protein molecular weight distributions were studied. The water‐soluble protein content was found to increase during malting and the increment was most significant on the first and second days. The molecular weight distribution of the wheat water‐soluble protein was analysed by high‐pressure size exclusion chromatography (HPSEC) and sodium dodecyl sulphate–polyacrylamide gel electrophoresis (SDS‐PAGE) methods. The HPSEC method showed that the content of all six molecular weight fractions (>24.4, 9.8–24.4, 3.9–9.8, 2.5–3.9, 0.4–2.5 and <0.4 kDa) of the water‐soluble protein increased. Among these, there was a considerable increase in the 0.4–2.5 and 2.5–3.9 kDa fractions. The >24.4, 9.8–24.4 and 3.9–9.8 kDa fractions showed a declining trend during steeping but an increase during the first 2 days of germination. The content of the 9.8–24.4 kDa fraction increased during the process of kilning. Wheat had a high percentage of the >24.4 and 9.8–24.4 kDa fractions, while wheat malt had a high percentage of the 2.5–3.9 and 0.4–2.5 kDa fractions. The molecular weight fractions of the water‐soluble protein had negative correlations with wheat malt viscosity and positive correlations with wheat malt extract. The SDS‐PAGE analysis showed that the band of the 60 kDa water‐soluble protein faded, while the bands of the 56, 44 and 12–15 kDa water‐soluble proteins became darker during malting. Copyright © 2014 The Institute of Brewing & Distilling     

Physicochemical,Pasting, and Functional Properties of Amaranth Seed Flours: Effects of Lipids Removal

The present work was carried out to evaluate physicochemical (composition, hunter color, and sodium dodecyl sulfate–polyacrylamide gel electrophoresis [SDS‐PAGE]), pasting, and functional properties (foaming, emulsification, water, and fat absorption capacity) of amaranth full‐fat flours from 6 lines/cultivars (AFs), and to see the effects of lipid removal/defatting on these properties. Protein, ash, and lipid content of AFs ranged between 12.5% to 15.2%, 3.0% to 3.5%, and 7.1% to 8.0%, respectively. The flours showed a number of bands between 97 and 7 kDa, with main subunits of approximately 58, 37, 33, 31, 23, and 16 kDa in the SDS‐PAGE profiles. The protein content and L* value increased, while b* values decreased following defatting for most of the lines/cultivars. The defatted flours (DAFs) had higher final viscosity and stability (lower breakdown viscosity) as compared to counterpart AFs. The protein profiling of the flours was not affected with the lipid removal/defatting. However, water absorption capacity and foam stability of the flours improved upon defatting. Principal component analysis revealed that pasting temperature was positively related to lipid content, while breakdown viscosity was negatively related to protein content. Foaming properties (capacity and stability) showed negative relationship with lipid content, and positive with protein content, ash content, water, and fat absorption capacity.     

Fabrication of W–20%Cu composite powder from copper and tungsten salts

Abstract

An investigation has been made to prepare homogeneous powders of CuWO₄ and WO₃ from ammonium paratungstate and copper nitrate to prepare nanosized W–Cu powder. Hence, a mixture of ammonium paratungstate and copper nitrate with predetermined weight proportion was made in distilled water; while the content of the beaker was being stirred at a certain speed to reach the desired composition of W–20 wt-%Cu. Mixture was heated to 80–100°C for 6 h. Also, pH range was adjusted at about 3–4. The mixture was then evaporated and dried in the air. To reach W–Cu composite powder, the precursor powders burned out at 520°C for 2 h in the air to form W–Cu oxide powder and then were ball milled and reduced in H₂ atmosphere to convert it into W–Cu composite powder. The resulting powders were evaluated using scanning electron microscopy, X-ray diffraction, thermogravimetric analysis and differential thermal analysis techniques. The results showed that homogeneous powders of W–Cu with particle size of ～100 nm and a nearly spherical shape could be obtained by this process.