• Journal of Nutrition and Health
• /
• v.51 no.1
• /
• pp.23-30
• /
• 2018

Purpose: Runx2 (runt-related transcription factor 2), a bone-specific transcription factor, is a key regulator of osteoblast differentiation and its expression is induced by the activation of BMP-2 signaling. This study examined whether zinc modulates BMP-2 signaling and therefore stimulates Runx2 and osteoblast differentiation gene expression. Methods: Two osteoblastic MC3T3-E1 cell lines (subclones 4 as a high osteoblast differentiation and subclone 24 as a low osteoblastic differentiation) were cultured in an osteogenic medium (OSM) as the normal control, Zn-($1{\mu}M$ Zn) or Zn+($15{\mu}M$ Zn) for 24 h. The genes and proteins for BMP-2 signaling (BMP-2, Smad-1/p-Smad-1), transcription factors (Runx2, osterix), and osteoblast differentiation marker proteins were assessed. Results: In both cell lines, BMP-2 mRAN and protein expression and extracellular BMP-2 secretion all decreased in Zn-. The expression of Smad-1 (downstream regulator of BMP-2 signaling) and p-Smad-1 (phosphorylated Smad-1) also downregulated in Zn-. Furthermore, the expression of the bone-specific transcription factors, Runx2 and osterix, decreased in Zn-, which might be due to the decreased BMP-2 expression and Smad-1 activation (p-Smad-1) by Zn-, because Runx2 and osterix both are downstream in BMP-2 signaling. Bone marker gene expression, such as alkaline phosphatase (ALP), collagen type I (COLI), osteocalcin, and osteopontin were also downregulated in Zn-. Conclusion: The results suggest that a zinc deficiency in osteoblasts suppresses the BMP-2 signaling pathway via the suppression of Smad-1 activation, and this suppressed BMP-2 signaling can cause poor osteoblast differentiation.

• Bulletin of the Korean Chemical Society
• /
• v.33 no.2
• /
• pp.636-640
• /
• 2012

We modify ZnO nanorods with Zn-porphyrin to obtain the improved characteristics of energy transfer, which is further investigated for the applicability to photovoltaic devices. A nitrogen heterocyclic ligand containing a thiol group is covalently grafted onto the surface of finely structured ZnO nanorods with a length of 50-250 nm and a diameter of 15-20 nm. Zn-porphyrin is then attached to the ligand molecules by the mechanism of metalligand axial coordination. The resulting energy band diagram suggests that the porphyrin-modified ZnO nanorods might provide an efficient pathway for energy transfer upon being applied to photovoltaic devices.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2001.11a
• /
• pp.543-548
• /
• 2001

The corrosion monitoring methods of reinforcing steel in concrete are the various methods such as half cell potential method, galvanic current method, resistivity method, polarization resistance method, AC impedance method and etc. In this study, the corrosion monitoring methods of reinforcing steel in concrete were investigated for the test specimens using corrosion inhibitors, zinc-mortar, zinc-plate, respectively. For this purpose, the accelerated corrosion tests for reinforcing steel were conducted according to the periodic cycles(140 days) of wetting($65^{\circ}C$, 90% R.H.) and drying period(15$^{\circ}C$ , 65% R.H.) for the test specimens. As a result, it can be concluded from the test that half cell potential and galvanic current method as monitoring techniques for corrosion were found to be relatively reliable and easily usable method in the field.

• Journal of the Korean Professional Engineers Association
• /
• v.14 no.4
• /
• pp.15-25
• /
• 1981

Electrical behaviors of the divalent silver oxide-zinc cell were analyzed for imporving capacity and keeping electrodes from passivation or sharp increases of cell internal resistance in the course of discharge. One of primary factors in relation to lowering performance can be depicted by cell internal resistance increase being created by various routes, first by insufficiency and/or the carbonation of the electrolyte, secondly by barrier blockage, thirdly by electrode passivation which are due to improper material use of wrong processing, and by gassing as fourth cause. The carbonation causes electrobyte to have impedance up as well as poor amalgamation, resulting in vigorous corrosion reaction of copper plated inner top, evolving hydrogen gas. Electrical characteristics of the cell was reviewed to elucidate relationships between the discharge capacity and the cell internal resistance.

• The Journal of the Korean dental association
• /
• v.15 no.4
• /
• pp.285-288
• /
• 1977

The purpose of the current study was to evaluate the effect of the zinc-deficient diet on the connectine tissue of oral mucosa in the albino rats. The zinc dificient diets were supplied to the rats for 4 weeks. The results were as follows: Most of the papillas of lamina prmina propria were shortened. The abnormal distribution and orientation of the fibrous elements were observed. The stain ability of fihrous elements in the Mallory azan stain was decreased. The amorphous intercellular substance showed slight metachromasia in the toluichine blue stain and low PAS reactinity.

• Journal of the Korean institute of surface engineering
• /
• v.35 no.5
• /
• pp.279-288
• /
• 2002

Zinc phosphating for cold forming of steel was studied with emphasis on decreasing phosphating temperature. To lower phosphating temperature, some techniques, such as adding Cu ion into bath, using activator in the form of pre-dip, and aeration in bath, instead of using conventional accelerator, namely oxidizing agent, have been tried. It was revealed that phosphating, leading to coatings of Improved uniformity and fine crystal size, can be carried out using above techniques at lower temperature ($55^{\circ}C$) compared to conventional phosphating temperature ($80 ~ 90^{\circ}C$ ). Under present condition, it was seen that optimum concentrations of Cu ion in phosphating bath and activator in pre-dip are 0.015% (w/w) and 2.0 g/1, respectively. The coating weight was within the range of 15 ~ 20 g/$\m^2$. When lubricant was applied into phosphating coatings, the amount of lubricating component (total soap) was found to be 6 ~ 10 g/$\m^2$ and the lubricated panel revealed excellent lubricating properties.

• Corrosion Science and Technology
• /
• v.11 no.1
• /
• pp.15-19
• /
• 2012

Both electrogalvanized and hot-dip galvanized steel sheets have been finally produced via organic-inorganic surface coating process on the zinc surface to enhance corrosion resistance and afford additional functional properties. Recently, POSCO has been developed a variety of chromate-free coated steels that are widely used in household, construction and automotive applications. New organic-inorganic hybrid coating solutions as chromate alternatives are comprised of surface modified silicate with silane coupling agent and inorganic corrosion inhibitors as an aqueous formulation. In this paper we have prepared new type of hybrid coatings and evaluated quality performances such as corrosion resistance, spot weldability, thermal tolerance, and paint adhesion property etc. The electrogalvanized steels with these coating solutions exhibit good anti-corrosion property compared to those of chromate coated steels. Detailed components composition of coating solutions and experimental results suggest that strong binding between organic-inorganic hybrid coating layer and zinc surface plays a key role in the advanced quality performances.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.20 no.6
• /
• pp.615-620
• /
• 1991

This study was performed to investigate the contamination level of harmful metals in 4 species of freshwater fishes collected at the three sampling sites of Yeong san river from January to October in 1990. The levels of total mercury, lead, zinc, manganese, copper and cadmium were ditermined and the results were summarized as follows : The overall range(ppm) were Hg, 0.022~0.139 ; Pb, 0.666~0.984 ; Zn, 8.673~15.214 ; Mn, 2.751~5.049 ; Cu, 0.328~1.174 ; Cd, 0.017~0.052. Among the six heavy metals contents, the highest was zinc and the lowest was cadmium. The results showed that all the 4 species of freshwater fishes of Yeong san river studied have not yet dangerous levels enough to pose a health problem.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2007.08a
• /
• pp.772-774
• /
• 2007

The improvement in the field emission parameters, luminescent uniformity, degradation rate and half life has been observed for the thin-multi wall carbon nanotube (t-MWCNT) composite, after incorporating the Zn nanoparticles. The Zn nanoparticles $(diameter\;{\sim}\;100\;{\pm}15\;nm)$ has been incorporated to synthesize the Zn-t-MWCNT composite.

• Journal of Plant Biology
• /
• v.15 no.3
• /
• pp.9-13
• /
• 1972

This report deals with lead and zinc contamination of roadside soil and plants caused by motor vehicles as a function of distance from the road edge. The concentrations of Pb and Zn in roadside soil and plant samples from several locations decrease regularly with increasing distance from traffic. Soil samples up to 24m distance from the road edge are contaminated with more than 12.99ppm lead, and 13.40ppm zinc. The decrease in Pb and Zn contamination with increasing distance from the road is characteristically curvilinear; the relative coefficiency of Pb and Zn with distance is -0.69, -0.48, respectively. The average contents of Pb and Zn in plants are 21.5ppm and 30.00ppm. It is suggested that the contamination is related to the composition of gasoline, motor oil and to roadside of the residues of this metals.