• Asian-Australasian Journal of Animal Sciences
• /
• v.29 no.9
• /
• pp.1247-1255
• /
• 2016

Heparin binding proteins (HBPs) are produced by accessory glands. These are secreted into the seminal fluid, bind to the spermatozoa at the time of ejaculation, favour capacitation, acrosome reaction, and alter the immune system response toward the sperm. The present study was conducted with an objective to assess the effect of purified seminal plasma-HBPs (SP-HBPs) on cross bred cattle bull sperm attributes during two phases of cryopreservation: Pre freezing and freezing-thawing. SP-HBPs were purified from pooled seminal plasma by heparin affinity chromatography. Three doses of SP-HBPs i.e. 10, 20, $40{\mu}g/mLs$ semen were standardized to find out the optimum dose and $20{\mu}g/mLs$ was found to be an optimum dose. Semen as such and treated with SP-HBPs was diluted with sodium citrate-egg yolk diluter and cryopreserved as per the standard protocol. Sperm parameters i.e. motility, viability, Hypo-osmotic swelling test (HOST), acrosome damage, in vitro capacitation and lipid peroxidation were evaluated in SP-HBP treated and untreated (control) semen at both phases of cryopreservation. A considerable variation in percent sperm motility, viability, membrane integrity (HOST), acrosome damage, acrosome reaction and lipid peroxidation was observed at both phases among the bulls irrespective of the treatment. Incubation of neat semen with $20{\mu}g/mL$ SP-HBP before processing for cryopreservation enhanced the average motility, viability, membrane integrity by 7.2%, 1.5%, 7.9%, and 5.6%, 6.6%, 7.4% in pre-frozen and frozen-thawed semen in comparison to control. There was also an average increase of 4.1%/3.9% in in vitro capacitation and acrosome reaction in SP-HBPs-treated frozen-thawed semen as compared to control. However, binding of SP-HBPs to the sperm declined acrosome damage and lipid peroxidation by 1.3%/4.1% and 22.1/$32.7{\mu}M$/$10^9$ spermatozoa in SP-HBP treated pre-frozen/frozen-thawed semen as compared to control, respectively. Significant (p<0.05) effects were observed only in motility, HOST and in vitro acrosome reaction. It can be concluded that treatment of neat semen with SP-HBPs before cryopreservation minimized the cryoinjury by decreasing the generation of reactive oxygen species.

• Macromolecular Research
• /
• v.11 no.6
• /
• pp.418-424
• /
• 2003

Exfoliated poly(methyl methacrylate-co-styrene) [P(MMA-co-ST)]/silicate nanocomposites were synthesized through a multistep emulsion polymerization. The methyl methacrylate monomers were polymerized first and then the styrene monomers were polymerized. The nanocomposites had core-shell structures consisting of PMMA (core) and PS (shell); these structures were confirmed by $^1$H NMR spectroscopy and TEM, respectively. P(MMA-co-ST) copolymers showed two molecular weight profiles and two glass transition temperatures (T$_{g}$) in GPC and DMA measurements. At 30 $^{\circ}C$, the nanocomposites exhibited 83 and 91 % increases in their storage moduli relative to the neat copolymer because the silicate layers were dispersed uniformly in the polymer matrix.x.

• Bulletin of the Korean Mathematical Society
• /
• v.52 no.5
• /
• pp.1549-1557
• /
• 2015

Characterizations of closed subgroups in abelian groups have been generalized to modules in essentially dierent ways; they are in general inequivalent. Here we consider the relations between these generalizations over commutative rings, and we characterize the commutative rings over which they coincide. These are exactly the commutative noetherian distributive rings. We also give a characterization of c-injective modules over commutative noetherian distributive rings. For a noetherian distributive ring R, we prove that, (1) direct product of simple R-modules is c-injective; (2) an R-module D is c-injective if and only if it is isomorphic to a direct summand of a direct product of simple R-modules and injective R-modules.

• Elastomers and Composites
• /
• v.31 no.1
• /
• pp.13-22
• /
• 1996

In order to Improve the fracture toughness of epoxy resin system, liquid chloroprene rubber(LCR) and liquid butadiene rubber (LBR) which have hydroxy group were used in the brittle epoxy system. Mechanical and toughness characterization of the modified epoxy resins were investigated as a function of liquid rubbers content. Epoxy resins modified with both of the liquid rubbers showed complete phase-separation microstructure : In all of the LCR content, it was observed that the domain size of LCR dispersed in the epoxy matrix ranging from $2{\mu}m\;to\;5{\mu}m$. It was found that fracture toughness, $K_{ic}$, of the modified LCR system was enhanced continuously as increasing LCR content. However around 10phr of LBR system showed maximum fracture toughness. Specifically, when BPA add to the modified LCR system, thermal and mechanical properties increased than neat epoxy. At the same time, fracture toughness was enhanced.

• Ceramist
• /
• v.9 no.6
• /
• pp.42-48
• /
• 2006

The structural ceramic, such as $A1_2O_3,\;ZrO_2\;and\;Si_3N_4$ have applied as several parts of precision machines, automotives and instruments for semiconductor. The mechanical properties depended on purity, morphology and microstructure of the ceramic and its fabrication process. High purity and fine starting powder for the structural ceramic was prepared mainly by wet process and powder processing such as milling, mixing, drying and granulating strongly influenced on the fabrication process. Powder processing included powder synthesis technology is essential for ceramic manufacture. Also, the advanced mechanical treat[neat in powder processing to create nano composite powder was developed to improve several properties of ceramic materials. Innovation of powder processing will lead to improve mechanical and functional properties of the ceramics.

• KIEAE Journal
• /
• v.3 no.3
• /
• pp.51-58
• /
• 2003

This Study aims to evaluate the interior atmospheres of atrium by glass colours. For the purpose, the 1/50 scale model of one-sided atrium was made and images of interior atmospheres were pictured under clear sky conditions. And then, questionnaire surveys were conducted on K university students in department architecture engineering. The survey results were analyzed by SPSS program. Frequency and correlation analysis were performed. As results, clear glass is chosen as the most preferred glass colour in any seasons. And, green and blue glasses are preferred in the order. And then, it is revealed that the main variables affecting satisfaction of interior atmospheres are a little changed by thermal senses of seasons. These variables are "bright", "neat", "warm", "comfort", "stable", "active", "static", "elegant" and "cool" through correlation analysis.

• Journal of Advanced Marine Engineering and Technology
• /
• v.31 no.5
• /
• pp.531-542
• /
• 2007

Simultaneous measurement technique for temperature and velocity fields near a heated solid body has been constructed. The measurement system consists of a 3-late CCD color camera, a color image grabber, a 1ighting system, a host computer and a software for the whole quantification process. Thermo Chromic Liquid Crystals (TCLC) was used as temperature sensors. A neural network was used to get a calibration curve between the temperature and the color change of the TCLC in order to enhance the dynamic range of temperature measurement. The velocity field measurement was attained by the use of the fray-level images taken for the flow field, and by introducing the cross-correlation technique. The temperature and the velocity fields of the forced and the natural convective flows neat the surface of a cartridge heater were measured simultaneously with the constructed measurement system.

• Bulletin of the Korean Chemical Society
• /
• v.30 no.3
• /
• pp.671-674
• /
• 2009

In this work, high-aspect-ratio graphite nanofibers (GNFs) were used to improve the electrical, thermal, and mechanical properties of the poly(methyl methacrylate) (PMMA) polymer, as well as those of PMMA composites suitable for use in bipolar plates. In the result, an electrical percolation threshold for the composites was formed between 1 and 2 wt% GNF content. This threshold was found to be influenced strongly by the three separate stages of the meltblending process. The composites exhibited higher thermal and mechanical properties and lower thermal shrinkage compared with the neat PMMA. Thus, GNFs were demonstrated to have positive impacts on the thermo-mechanical properties of PMMA composites and showed, thereby, reasonable potential for use in composites employed in the fabrication of bipolar plates.

• Journal of Korean Elementary Science Education
• /
• v.24 no.1
• /
• pp.59-67
• /
• 2005

The purpose of this study is to investigate the elementary school students' perceptions of scientist and socio-cultural background towards science. Subjects are 120 ordinary students of elementary school and 75 participators in invention club and science camp for talented students in a metropolitan city. A questionnaire for investigating the students' perceptions and Images about scientist was developed. That contains the items for socio-cultural background and experiences towards science. The results of this study showed that the elementary students think scientist is younger than the previous students thought. But as yet, the representative image of scientist is the neat man with glasses and gown. Also, a majority of elementary students like science, science subject and science classroom, especially experiment activity. They have various experiences related in science.

• Transactions on Electrical and Electronic Materials
• /
• v.18 no.4
• /
• pp.203-206
• /
• 2017

The effect of the content of microsilica and nanosilica continuously modified with hydroxy silane and epoxy-modified silicone in cycloaliphatic epoxy/microsilica/nanosilica composites (EMNCs) on the mechanical and water repellent properties was evaluated. Surface-modified micro- and nanosilica was well-mixed with a cycloaliphatic epoxy resin in the presence of polyester-modified polydimethylsiloxane (PEM-PDMS) as a dispersing agent using an ultrasonicator. Tensile and flexural tests were carried out using a universal testing machine (UTM). The water repellent property was evaluated by contact angle measurements of water on the composite surface. Tensile strength of the composite could be enhanced by 32.2% up to 91.4 MPa, and the flexural strength was raised to 122.0 MPa, which is 38.8% higher than that of neat epoxy. The contact angle of water on the composite was as high as $104.1^{\circ}$.