• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.418-418
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• 2008

The electrochemical etching of silicon in HF-based solutions is known to form various types of porous structures. Porous structures are generally classified into three categories according to pore sizes: micropore (below 2 nm in size), mesopore (2 ~ 50 nm), and macropore (above 50 nm). Recently, the formation of macropores has attracted increasing interest because of their promising characteristics for an wide scope of applications such as microelectromechanical systems (MEMS), chemical sensors, biotechnology, photonic crystals, and photovoltaic application. One of the promising applications of macropores is in the field of MEMS. Anisotropic etching is essential step for fabrication of MEMS. Conventional wet etching has advantages such as low processing cost and high throughput, but it is unsuitable to fabricate high-aspect-ratio structures with vertical sidewalls due to its inherent etching characteristics along certain crystal orientations. Reactive ion dry etching is another technique of anisotropic etching. This has excellent ability to fabricate high-aspect-ratio structures with vertical sidewalls and high accuracy. However, its high processing cost is one of the bottlenecks for widely successful commercialization of MEMS. In contrast, by using electrochemical etching method together with pre-patterning by lithographic step, regular macropore arrays with very high-aspect-ratio up to 250 can be obtained. The formed macropores have very smooth surface and side, unlike deep reactive ion etching where surfaces are damaged and wavy. Especially, to make vertical microwire or nanowire arrays (aspect ratio = over 1:100) on silicon wafer with top-down photolithography, it is very difficult to fabricate them with conventional dry etching. The electrochemical etching is the most proper candidate to do it. The pillar structures are demonstrated for n-type silicon and the formation mechanism is well explained, while such a experimental results are few for p-type silicon. In this report, In order to understand the roles played by the kinds of etching solution and mask patterns in the formation of microwire arrays, we have undertaken a systematic study of the solvent effects in mixtures of HF, dimethyl sulfoxide (DMSO), iso-propanol, and mixtures of HF with water on the structure formation on monocrystalline p-type silicon with a resistivity with 10 ~ 20 $\Omega{\cdot}cm$. The different morphological results are presented according to mask patterns and etching solutions.

• Journal of Life Science
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• v.21 no.8
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• pp.1094-1099
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• 2011

Antimicrobial efficacy of high pressure (HP) can be enhanced by the application of additional hurdles. The objective of this study was to assess the enhancement in pressure lethality by tert-butylhydroquinone (TBHQ) treatment, against bacterial spores that are considered significant in the food industry. Spores of Clostridium sporogenes, Bacillus cereus and B. subtilis were prepared. Spore suspensions containing TBHQ (200 ppm, dissolved in dimethyl sulfoxide, DMSO) were pressurized at 650 or 700 MPa at 54-72$^{\circ}C$ for 5 min. Inactivation of bacterial spores resulted only with HP treatment. The population of B. subtilis spores was more inactivated by HP than those of B. cereus and C. sporogenes spores. Inactivation of C. sporogenes spores using pressure was more affected by the germinated population, compared to Bacillus spores. The inactivation of Bacillus spores increased when pressurized at 70$^{\circ}C$, compared to 54$^{\circ}C$. On the other hand, the degree of germination-induced lethality for Bacillus spores decreased at 70$^{\circ}C$. When spores were treated with a combination of DMSO-HP and TBHQ-HP, these treatments seemed to protect the spores against HP, especially at 54$^{\circ}C$. Further mechanistic studies involved in inducing germination by HP and using a subsequent sporicidal agent will be needed for a better understanding of bacterial spore inactivation.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.4
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• pp.485-493
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• 2002

Different factors may affect the sensitivity of porcine oocytes during cryopreservation. The effect of two methods (cooling and vitrification), four cryoprotectants [glycerol (GLY), 1, 2-propanediol (PROH), dimethyl sulfoxide (DMSO) or ethylene glycol (EG)] and two vitrification media (1 M sucrose (SUC)+8 M EG; 8 M EG) on the developmental capacity of porcine oocytes at the germinal vesicle (GV) stage or after IVM at the metaphase II (M II) stage were examined. Survival was assessed by FDA staining, maturation and cleavage following IVF and IVC. A toxicity test for different cryoprotectants (GLY, PROH, DMSO, EG) was conducted at room temperature before cooling. GV and M II-oocytes were equilibrated stepwise in 1.5 M cryoprotectant and diluted out in sucrose. The survival rate of GV-oocytes in the GLY group was significantly lower (82%, p<0.01) than that of the other group (92 to 95%). The EG group achieved a significantly higher maturation rate (84%, p<0.05) but a lower cleavage rate (34%, p<0.01) than the DMSO group and the controls. For M II-oocytes, the survival rates for all groups were 95 to 99% and the cleavage rate of the GLY group was lower than the PROH-group (21 vs 43%, p<0.01). After cooling to $10^{\circ}C$, the survival rates of GV-oocytes in the cryoprotectant groups were 34 to 51%, however, the maturation rates of these oocytes were low (1%) and none developed after IVF. For M II-oocytes, the EG group showed a significantly higher survival rate than those of the other cryoprotectant groups (40% vs 23-26%, p<0.05) and the cleavage rates of PROH, DMSO and EG group reached only 1 to 2%. For a toxicity test of different vitrification media, GV and M II-oocytes were equilibrated stepwise in 100% 8 M EG (group 1) and 1 M SUC + 8 M EG (group 2) or equilibrated in sucrose and then in 8 M EG (SUC+8 M EG, group 3). For GV-oocytes, the survival, maturation and cleavage rates of Group 1 were significantly lower than those in group 2, 3 and control group (p<0.05). For M II-oocytes, there were no differences in survival, maturation and cleavage rates between groups. After vitrification, the survival rates of GV and M II-oocytes in group 2 and 3 were similarly low (4-9%) and none of them matured nor cleaved after in vitro maturation, fertilization and culture. In conclusion, porcine GV and M II-oocytes do not seem to be damaged by a variety of cryoprotectants tested, but will succumb to a temperature decrease to $10^{\circ}C$ or to the process of vitrification, regardless of the cryoprotectant used.

• Clinical and Experimental Reproductive Medicine
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• v.29 no.2
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• pp.139-147
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• 2002

Objective : This study was to establish a reproducible differentiation system from the parthenogenetic mouse embryonic stem (P-mES02) cells into functional cardiomyocytes like as in vitro fertilization mouse embryonic stem (mES01) cells. Materials and Methods: To induce differentiation, P-mES02 cells were dissociated and aggregated in suspension culture environment for embryoid body (EB) formation. For differentiation into cardiomyocytes, day 4 EBs were treated with 0.75% dimethyl sulfoxide (DMSO) for another 4 days (4-/4+) and then were plated onto gelatin-coated dish. Cultured cells were observed daily using an inverted light microscope to determine the day of contraction onset and total duration of continuous contractile activity for each contracting focus. This frequency was compared with the results of DMSO not treated P-mES02 group (4-/4-) and mES01 groups (4-/4+ or 4-/4-). For confirm the generation of cardiomyocytes, beating cell masses were treated with trypsin-EDTA, dispersed cells were plated onto glass coverslips and incubated for 48 h. Attached cells were fixed using 4% paraformaldehyde and incubated with specific antibodies (Abs) to detect cardiomyocytes (anti-sarcomeric ? -actinin Ab, 1 : 100; anti-cardiac troponin I Ab, 1 : 2000) for 1 h. And the cells were finally treated with FITC or TRITC labelled 2nd Abs, respectively, then they were examined under fluorescence microscopy. Results: Rhythmically contracting areas in mES01 or P-mES02 cells were firstly appeared at 9 or 10 days after EBs plating, respectively. The highest cumulative frequency of beating EBs was not different in both treatment groups (mES01 and P-mES02, 4-/4+) with the results of 61.3 % at 13 days and 69.8% at 15 days, respectively. Also, the contracting duration of individual beating EBs was different from minimal 7 days to maximal 53 days. However, DMSO not treated groups (mES01 and P-mES02, 4-/4-) also had contracting characteristics although their frequency was a few compared to those of DMSO treated groups (6.0% and 4.0%). Cells recovered from the spontaneously contracting areas within EBs in both treated groups were stained positively with muscle specific anti-sarcomeric ? -actinin Ab and cardiac specific anti-cardiac troponin I Ab. Conclusion: This study demonstrated that the P-mES02 cell-derived cardiomyocytes displayed similarly structural properties to mES01 cell-derived cardiomyocytes and that the DMSO treatment enhanced the cardiomyocytes differentiation in vitro.

• Archives of Plastic Surgery
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• v.35 no.6
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• pp.645-652
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• 2008

Purpose: In skin flap surgery, surgeons often encounter distal ischemia of the flap. If a powerful free radical scavenger is used, it may reduce the formation of free radical and improves the survival of flap. Thus, the present study purposed to examine whether the survival of flap can be enhanced by administering melatonin, which is known to be a powerful free radical scavenger a antioxidant molecule. Methods: We divided 40 Sprague-Dawley rats into 4 groups, 10 in each group. For the control group(n=10), we intraperitoneally injected only carrier solution once 30 minutes before the operation, and once a day for 7 days from the day of operation. Among the experimental groups, a group(n=10) was administered with dimethyl sulfoxide(DMSO), in another group(n=10), melatonin was intraperitoneally injected, and in the other(n=10) melatonin was intraperitoneally injected and applied topically(2 cc of 1% melatonin) to the operation site. Caudally based skin flaps measuring $3{\times}10cm^2$ were elevated on the mid-dorsum of the rats. and then repositioned. On the seventh postoperative day, the survival area of the flap was measured and tissues were examined under the light microscope. Results: The control group, the DMSO group, the melatonin administration group and the melatonin administration and application group showed the mean survival rates of $55.26{\pm}9.2%$, $70.29{\pm}7.47%$, $81.45{\pm}4.14%$ and $86.1{\pm}1.52%$, respectively, for $30cm^2$ of flap. Compared to the control group, the experimental groups showed a significantly high increase in survival area at significance level of 95%. Conclusion: In this study, the survival rate of flap was enhanced through the administration of melatonin after flap surgery. This suggests that melatonin not only functions as a powerful free radical scavenger and oxygen radical scavenger but also stabilizes and protects cells, and by doing so, enhances the survival of moderately injured ischemic sites in the distal end of flap.

• Preventive Nutrition and Food Science
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• v.19 no.3
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• pp.136-144
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• 2014

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. This study was conducted to evaluate the effects of Platycarya strobilacea S. et Z. (PSE) extract on mouse hair growth and to determine the mechanism of action of PSE. PSE was purchased and its antioxidant activities, such as electron donating ability, total polyphenol content, and flavonoid content were tested. Toxicity during topical treatment was determined by the CCK-8 assay, a cell viability test. Fifteen 4-week-old male C57BL/6 mice were assigned to receive one of three treatments: dimethyl sulfoxide (negative control), minoxidil (positive control) or PSE. Test materials were topically applied to the shaved dorsal skin of each mouse daily for 3 weeks. After 21 days, we observed skin tissue hair follicle morphology and length, mast cell number, and stem cell factor (SCF) expression using hematoxylin and eosin (H&E), toluidine blue, and immunohistochemical staining, respectively. Furthermore, the expression of cytokines involved in hair growth [i.e., insulin-like growth factor (IGF)-1, keratinocyte growth factor (KGF), and transforming growth factor (TGF)-${\beta}1$] was determined by PCR. PSE was found to have very high antioxidant activity. The cell viability rate of PSE-treated mice was markedly higher than that of mice in the control group. We also observed an increase in hair follicle length, strong SCF staining, and a decrease in mast cell number in the PSE group. In addition, PSE-treated mice had higher IGF-1 and KGF expression and lower TGF-${\beta}1$ expression than mice in the minoxidil-treated group. These results suggest that topical application of PSE promotes hair growth by intensifying SCF, suppressing mast cell production, and increasing hair growth-promoting cytokine expression.

• Reproductive and Developmental Biology
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• v.39 no.3
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• pp.77-81
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• 2015

This study was carried out to evaluate the effects of embryonic stage and toxicities of cryoprotectant on the rates of survival and development of the cryopreserved mouse early embryo and finally to establish the cryopreservation method of surplus embryos obtained during assisted reproductive technology. Toxicities of two cryoprotectants, dimethyl sulfoxide (DMSO) and ethylene glycol (EG) were investigated using a murine embryo model. Female F-1 mice were stimulated with gonadotropin, induced ovulation with hCG and mated. Two cell embryos were collected and cultured after exposure to either DMSO or EG. Embryo development was evaluated up to the blastocyst stage. The total cell count of blastocysts that were treated with DMSO ($68.1{\pm}24.1$) at the 2-cell stage was significantly lower than that were treated with EG ($81.2{\pm}27.0$) or the control ($99.0{\pm}18.3$) (p<0.001). On comparison of two cryoprotectant treated groups, the DMSO treated group showed a decreased cell count compared with the EG treated group (p<0.05). Both DMSO ($15.4{\pm}1.5$) and EG ($10.2{\pm}1.4$) treated groups showed higher apoptosis rates of cells in the blastocyst compared with the control ($6.1{\pm}0.9$, p<0.0001). In addition, the DMSO treated group showed more apoptotic cells than the EG treated group (p<0.001). The potential toxicity of cryoprotectants was uncovered by prolonged exposure of murine embryos to either DMSO or EG at room temperature. When comparing two cryoprotective agents, EG appeared to be less toxic than DMSO at least in a murine embryo model.

• Development and Reproduction
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• v.13 no.3
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• pp.173-181
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• 2009

One of the most extensively studied populations of multipotent adult stem cells are mesenchymal stem cells (MSCs). MSCs derived from the human umbilical cord vein (HUC-MSCs) are morphologically and immunophenotypically similar to MSCs isolated from bone marrow. HUC-MSCs are multipotent stem cells, differ from hematopoietic stem cells and can be differentiated into neural cells. Since neural tissue has limited intrinsic capacity of repair after injury, the identification of alternate sources of neural stem cells has broad clinical potential. We isolated mesenchymal-like stem cells from the human umbilical cord vein, and studied transdifferentiation-promoting conditions in neural cells. Dopaminergic neuronal differentiation of HUC-MSCs was also studied. Neural differentiation was induced by adding bFGF, EGF, dimethyl sulfoxide (DMSO) and butylated hydroxyanisole (BHA) in N2 medium and N2 supplement. The immunoreactive cells for $\beta$-tubulin III, a neuron-specific marker, GFAP, an astrocyte marker, or Gal-C, an oligodendrocyte marker, were found. HUC-MSCs treated with bFGF, SHH and FGF8 were differentiated into dopaminergic neurons that were immunopositive for tyrosine hydroxylase (TH) antibody. HUC-MSCs treated with DMSO and BHA rapidly showed the morphology of multipolar neurons. Both immunocytochemistry and RT-PCR analysis indicated that the expression of a number of neural markers including NeuroD1, $\beta$-tubulin III, GFAP and nestin was markedly elevated during this acute differentiation. While the stem cell markers such as SCF, C-kit, and Stat-3 were not expressed after neural differentiation, we confirmed the differentiation of dopaminergic neurons by TH/$\beta$-tubulin III positive cells. In conclusion, HUC-MSCs can be differentiated into dopaminergic neurons and these findings suggest that HUC-MSCs are alternative cell source of therapeutic treatment for neurodegenerative diseases.

• Reproductive and Developmental Biology
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• v.30 no.1
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• pp.47-52
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• 2006

This study was conducted to examine whether the parthenogenetic mouse embryonic stem (P-mES) cells can differentiate into functional cardiomyocytes in vitro similar to (mES) cells. p-mES04 and IVF-derived mES03 cells were cultured by suspension culture for 4 days. The formed embryoid bodies (EBs) were treated with 0.75% dimethyl-sulfoxide (DMSO) for further 4 days (4-/4+), and then plated onto gelatin coated culture dish. The appearance of contracting cardiomyocytes from the P-mES04 and mES03 cells was examined for 30 days. The highest cumulative frequency was detected at days 13 (69.83%) and 22 (61.3%), respectively. By immunocytochemistry, beating P-mES04 cells were positively stained with muscle specific anti-sarcomeric a-actinin Ab and cardiac specific anti-cardiac troponin I Ab similar to contracted mES03 cells. When the expression of cardiac muscle-specific genes was analyzed by RT-PCR, beating P-mES04 cells were expressed cardiac specific L-type calcium channel, a1C, cardiac myosin heavy chain a, cardiac muscle heavy polypeptide $7{\beta}$, GATA binding protein 4 and atrial natriuretic factor, but not expressed skeletal muscle specific L-type calcium channel, a1S, which was similar to male adult heart cells and mES03-derived beating cardiomyocytes. The result demonstrates that the P-mES cells can be used as an alternative for the study on the characteristic analysis of in vitro cardiomyocyte differentiation from the ES cells.

• Journal of the East Asian Society of Dietary Life
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• v.24 no.6
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• pp.776-784
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• 2014

Korean dishes, Hansik are characterized by healthful vegetable intake. The purpose of this study was to evaluate the inhibitory effect of commonly consumed vegetables by Koreans on obesity/metabolic disease-related inflammation. Through statistical analysis of the KNHANES database ($1^{st}$ 1998, $5^{th}$ 2010, 2011) and a literature review, we selected vegetables for study. Among the vegetables, main or sub ingredients of Kimchi were excluded. Samples were prepared using only edible portions and freeze-dried. After grinding, samples were extracted with ethanol, evaporated and finally lyophilized. The cytotoxicity of samples was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, at various concentrations that do not affect cell viability. Raw 264.7 macrophages were treated with lipopolysaccharide (LPS) and 11 kinds of samples or positive control (troglitazone) dissolved in dimethyl sulfoxide (DMSO). After 24 hours, nitric oxide (NO), tumor necrosis factor ${\alpha}$ (TNF-${\alpha}$) and monocyte chemoattractant protein-1 (MCP-1) production were determined. Excepts for young pumpkin and bracken, nine samples effectively reduced NO production compared with control treated with LPS and DMSO. NO levels of five samples (bean sprouts, leeks, eggplant, mugwort, and pumpkin) were similar to that of the positive control. These five samples showed significantly decreased TNF-${\alpha}$ or MCP-1 compared to the control group. Our results suggest that consumption of commonly consumed vegetables contributes to partial prevention of obesity and related metabolic syndrome through reduction of NO, TNF-${\alpha}$, and MCP-1 production.