Effect of magnesium chloride on fractionation and enzymatic digestibility of cattails

The effect of magnesium chloride (a Lewis acid) on the fractionation of aquatic plant cattail was studied using a Dionex accelerated solvent extractor varying salt concentration (0–0.4 M), treatment temperature (140–180°C), and residence time (5–15 min). MgCl₂ treatment enhanced xylan degradation and delignification, and up to 33.8% of total xylan was directly hydrolyzed to the xylose monomer. By removing xylan and lignin, the MgCl₂ treatment effectively increased enzymatic digestibility of cattail cellulose and xylan. When cattails were treated with the 0.4 M MgCl₂ at 180°C for 15 min and subsequently hydrolyzed for 48 h with a cellulase loading of 15 FPU/g glucan, the highest glucose yield of 61.7% and the highest total xylose yield of 90.6% were reached, respectively. Application of Lewis acids as a novel biomass fractionation approach will require lower xylanase loading for hydrolysis, and have lower corrosion to equipment compared to other acid pretreatment processes.     

Polypyrrole as an Efficient Solid-Phase Extraction Sorbent for Determination of Chloramphenicol Residue in Chicken Liver,Kidney, and Meat

A novel, sensitive, inexpensive, and efficient method for the extraction and pre-concentration of chloramphenicol residue in chicken tissues has been developed. In this work, polypyrrole polymer was synthesized and used as an efficient sorbent for solid-phase extraction. Several parameters such as type of salt, salting out effect, pH of extraction solution, temperature, and desorption solvent were optimized. The samples were analyzed by high performance liquid chromatography coupled to photodiode array detection. Under optimized extraction and cleanup conditions (namely, Britton–Robinson buffer 0.1 M adjusted to pH 2.0 with NaCl at 35 °C and using of methanol as desorption solvent), the method showed good linearity and sensitivity. Recovery was in the range of 86.0–93.4, 80.8–89.5, and 77.5–85.6 % for meat, kidney, and liver, respectively. Relative standard deviation was lower than 10 % in all cases indicating that the method can be used as a validated method. The limit of detection and limit of quantitation of the proposed method at various matrices were found to be in the range of 0.1–1 and 0.3–3 ng/g, respectively. These results suggested that the solid-phase extraction base on polypyrrole might be a potential candidate for the extraction of chloramphenicol from chicken tissues.     

符合RoHS禁令的厚膜金导体浆料

出于对健康和环境的考虑,限制铅、镉和含有其它有毒物质在混合集成电路产品应用的需求越来越大。根据2006年7月1日生效的欧盟禁令(即RoHS)这些物质是禁用的,电路生产商急于找到可以替换现有含铅和镉的产品。镉氧化物在厚膜金浆料中可以起到很好的粘附作用。金厚膜浆料主要用于要求高机械强度的领域,比如医疗器械,军事应用和高频电路。现在的挑战是开发一新的和传统的含镉浆料具有相同性能的无镉导体金浆料。在过去的10年中,贺利氏超前地研发了无铅无镉厚膜产品。到目前,贺利氏已经开发并且打入一些环保型厚膜产品市场。讨论一种新开发的厚膜导体金浆料,给出了在96%氧化铝基板和绝缘体基板上分别焊接金线和铝线的线键合数据。数据显示无铅无镉金导体和RoHS规定的可锡焊导体之间的匹配性,结果表明它可以应用于混合金属电路。     

Creep analysis of adhesively bonded single lap joint using finite element method

Adhesive joints are being used widely in engineering industries due to the increasing demand for designing lightweight structures. Because of the physical properties of the most adhesives, they creep even at room temperature. Therefore, the creep behavior of a single lap adhesive joint is studied in this paper. For this purpose, using the experimental data, creep constitutive equations for the adhesive has been obtained. Then, these equations have been employed to investigate the creep behavior of the joint. The results show that due to the creep straining, the stresses in the joint corners, decrease. However, creep strain accumulates in these areas which this in turn may lead to separation of adhesive from adherent. In order to eliminate the effect of strain accumulation, two modifying methods have been proposed in this paper: increasing the layer thickness and using filleted joints.     

Determination of tetracyclines in meat using two phases freezing extraction method and HPLC-DAD

Food Analytical Methods - The protein binding of tetracyclines may cause the common extraction methods are not able to completely remove them from the proteins. To overcome this problem, we...     

Carbohydrate and protein sources influence the induction of α- and β-galactosidases in Lactobacillus reuteri

The induction of α- and β-galactosidases in six strains of Lactobacillus reuteri (L. reuteri) by six carbohydrate sources and four protein sources was studied. L. reuteri grown on raffinose had the highest α-galactosidase activity (10.55 Gal U/ml), while lactose exhibited the highest β-galactosidase activity (43.82 Gal U/ml) when compared to other carbohydrate sources. L. reuteri grown on yeast extract exhibited the highest α- and β-galactosidases activity (15.27 and 12.88 Gal U/ml, respectively) when compared to other protein sources. MF14C and SD2112 grown on raffinose had the highest α-galactosidase activity (14.75 and 14.18 Gal U/ml, respectively) followed by CF2-7F (13.38 Gal U/ml). CF2-7F grown on lactose had the highest β-galactosidase activity (82.01 Gal U/ml). SD2112, MM2-3 and CF2-7F grown on yeast extract (20.96, 19.67, 19.67 Gal U/ml, respectively) showed the highest α-galactosidase activity. MM2-3 and CF2-7F grown on yeast extract showed the highest β-galactosidase activity (18.1 and 17.59 Gal U/ml, respectively). Raffinose and lactose were the best carbohydrate sources to produce α- and β-galactosidases, respectively. Yeast extract was the best protein source to produce both enzymes and CF2-7F strain was the best producing strain on all tested conditions.     

Investigation of Spatial Distribution of Hydrogen and Argon Ions and Effects of them on Aluminum Samples in a 2.5 kJ Mater Type Plasma Focus Device

In this work the effects of Hydrogen and Argon ions on Aluminum samples and the spatial distribution of the ions in 2.5 kJ SBUPF1 Mather type plasma focus device in different distance from the anode top have been investigated. For each gas the pressure and operation voltage have been determined to have maximum ion density. Aluminum samples were placed at different distances above the anode. Irradiated samples have been analyzed with SEM technique for morphological and surface study of samples. Melting and surface evaporation effects and generation of cracks were seen in these samples. The result of ions patterns on these samples can be used to determine ions spatial distribution on top of the anode region. The EDX spectroscopy and the SRIM calculations have been done to determine the composition of samples and the penetration depth of the ions in the samples respectively.