食物源蛋白酶解制备抗菌肽研究

抗菌肽广泛分布于细菌、病毒和各种动植物体内,是生物天然免疫防御系统的重要组成部分。在耐药菌株不断产生的今天,抗菌肽的研究吸引着国内外学者目光。本文综述了乳源蛋白和非乳源蛋白酶解制备抗菌肽、酶解作用提高抗菌蛋白的抗菌性、酶及酶解条件的选择、抗菌产物目的性修饰提高抗菌性的研究,并展望了食物源蛋白酶解制备抗菌肽的未来研究方向。     

Conjugate free convection above a cooled finite horizontal flat plate embedded in a porous medium

We investigate conjugate free convection in a semi-infinite porous medium above a cold finite plate. Numerical solutions of the coupled governing equations for the fluid and the plate regions are obtained, and an analytical method is developed to predict the average temperature of the conjugate boundary and the Nusselt number.     

Studies on phytohormones,vitamins and mineral element requirements of Lentinus subnudus (Berk) and schizophyllum commune (Fr. Ex. Fr) from Nigeria

The effects of phytohormones, vitamins and mineral elements on growth of Lentinus subnudus (Berk) and Schizophyllum commune (Fr. ex Fr), two Nigerian edible mushrooms, were studied. Among the phytohormones tested, 1.0 ppm of 2,4 D stimulated the best growth in L. subnudus, followed by 0.1 ppm of GA3. As for S. commune, 10.0 ppm of 2, 4 D enhanced the best growth while 1.0 ppm of GA3 was the second best. The least stimulatory hormone for the two mushrooms was GA3 at 20.0 ppm concentration. Among the vitamins, biotin was the most utilizable for L. subnudus, followed in order by thiamine and folic acid. Pyridoxine promoted best growth for S. commune while the poorest growth was supported by pantothenic acid. In both higher fungi, macroelements (Mg, K and Ca) promoted good mycelial growth but Na was least utilised. Similarly, trace elements (Zn, Fe and Mn) also supported growth to a significant level (P=0.01). The implication of the obtained results are discussed in relation to the cultivation of L. subnudus and S. commune in Nigeria.     

High-speed plating for electronic applications

A permanent task of the electronic industry is to find methods in order to reduce production costs which are characterised by higher mass-production output. Besides the choice of less expensive coating materials, high-speed plating is a further possibility. High-speed plating brings about an increase in output or a minimisation of ground space and/or investment. The publication describes the principles, possibilities and limitations of high-speed plating technology in the scope of four different applications. These applications are: the selective coating of contact materials in reel-to-reel continuous plating lines, the continuous copper plating of printed circuit boards, the high-speed plating in product-specific plating tools integrated into an inter-linked production and the electroforming of microstructures.     

Relationship between impact energy and compression toughness energy of high-strength fiber-reinforced concrete

A simple, economical, and practical drop-weight impact testing machine was developed to determine the impact resistance for high-strength fiber-reinforced concrete (HSFRC) composite. Impact and compression tests were carried out on concrete cylinders reinforced with three different aspect ratios of hooked-end steel fibers l/d (length/diameter): 60, 75, and 83 (30/0.50, 60/0.80, and 50/0.60 mm/mm), and four different percentages of steel fibers 0.5%, 1.0%, 1.5% and 2.0% by volume of concrete. For each aspect ratio and volume of fibers, complete stress–strain curves of HSFRC were generated in order to determine the total energy absorbed for each cylindrical specimen in compression. The addition of steel fibres to concrete has improved impact resistance and also the compression toughness. The test results showed that a logarithmic relation exists between compression toughness energy (E_Ct) by means of the generated stress–stress curves from the compressive tests and the impact energy (E_I) by means of the modified impact machine for HSFRC at different l/d ratio of 60, 75, and 83.     

Synthesis of soluble oligo(2,5-dioctyloxyphenylene)s by mild oxidative coupling

Oligo(2,5-dioctyloxyphenylene)s, with DP=6–7, have been synthesized in one step from 1,4-dioctyloxybenzene by the Scholl reaction using molybdenum pentachloride as an oxidative agent. The structural characterization by ¹³C-NMR, UV–vis and X-ray fluorescence spectroscopy has shown that in optimized reaction conditions oligo(2,5-dioctyloxyphenylene)s with their monomer units predominantly connected in para position are formed. Noteworthy are the Cl atom content <1 mol% and the intense emission centered around 400 nm which make these oligo(2,5-dioctyloxyphenylene)s appealing functional materials.     

Structural and physical properties of soybean protein isolate films with ohmic heating treatment: Impacts of electric field

The effects of ohmic heating (OH) and conventional heating (CON) on the structural and physical properties of soybean protein isolate (SPI) and SPI films were studied. When the electric field was varied from 0 to 12 V·cm⁻¹, the fluorescence intensity, average particle size, and polydispersity index (PDI) of the OH-SPI were the least at 9 V·cm⁻¹ and increased thereafter. Meanwhile, the free SH-group content and surface hydrophobicity were the maximum at 9 V·cm⁻¹ and decreased thereafter. Moreover, the α-helix content decreased and the random coil content increased noticeably at 12 V·cm⁻¹. In terms of the properties of the SPI films, the mechanical properties and water resistance of the OH-SPI films were superior to those of the CON-SPI films. When the electric field was 9 V·cm⁻¹, the tensile strength of the OH-SPI film increased from 2.76 MPa to 4.34 MPa, and the elongation at break of the OH-SPI films improved. Moreover, the water resistance of the OH-SPI films was the best at this electric field.     

Simulation of diesel hybrid electric vehicle containing hydrogen enriched CI engine

Hydrogen enrichment on diesel engines is a proven solution for both minimizing the undesirable emissions and fuel consumptions. Also, hybrid electric vehicles which manufactured for the same goal too, are playing an important movement during three decades in transportation sector. The combination of these two common-purpose technologies will give possibility to production of hybrid electric vehicles which have hydrogen-enriched internal combustion engine, in the near future.At this study, four type modelled vehicle; stock diesel vehicle (V1), hydrogen enrichment diesel vehicle (V2), hybrid electric vehicle which contains same diesel engine (V3) and hybrid electric vehicle that powered by hydrogen enrichment diesel engine (V4); simulated with AVL simulation tools for compared the performance and emission values, for the first time. V1 is outfitted by 3.0 L diesel engine. V2 is the hydrogen enriched version of V1 which hydrogen addition is conducted via intake manifold with 8% (vol/vol) enrichment. V1 and V2 were simulated under AVL Boost tool for analyzing the effects of hydrogen addition clearly. After that, V3 and V4 were modelled with AVL Cruise. V3 and V4 were coupled an electric motor (30 kW) with appropriate battery. In terms of performance and emissions results, vehicle types with hydrogen enriched diesel engines were given promising outputs when compared with without ones. In particular, V4 has revealing excellent performance. Under this study's circumstances, when compared V4 between stock one, 4.26% improvement was achieving on vehicle performance parameters. Additionally, the combined fuel consumption, NOx emission and CO2 emission decreases with 14.32%, 15% and 33% respectively, for comparison between V4 and V1.     

春季渤海湾营养盐分布及潜在性富营养化评价

根据2011年5月对渤海湾海域20个站位海水营养盐的调查结果,分析该海区海水营养盐的分布特征,并进行了潜在性富营养化评价．研究发现,调查海域NO3--N质量浓度为150．5～276.3ug/L,NO2--N质量浓度为4．072．29．490ug／L,NH4＋-N、PO4 3-- P和SiO3 2-Si质量浓度分别为47．55～194．80ug／L、4．73～26．35ug／L和170．2—544．1ug/L．整体上,各类无机氮呈现出表底层差异不大、沿岸浓度高、外海浓度低的特点;断面分布呈现出由东向西逐渐升高的趋势,SiO23 2- -Si相反,NO3- -N、NH4--N和SiO2 3--Si质量浓度呈现出由北向南逐渐升高的趋势,而NO2--N、VO4 3--P质量浓度出现北高南低的情形．渤海湾连续站显示出一定的营养盐浓度随潮汐的韵律变化,其中NO3--N、NO2--N和NH4＋-N质量浓度变化相对较明显,低潮较高潮期间营养盐浓度高．营养盐与盐度的相关性不很显著．NO3 --N是溶解无机氮（DIN）的主要组成形式,占平均DIN含量的69．56％;该海区主要以磷限制为主,并已经逐渐从P限制向P、Si共同限制方向发展,这与潜在性富营养化评价结果一致．