• Journal of Microbiology and Biotechnology
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• v.34 no.8
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• pp.1580-1591
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• 2024

Menopause is induced by spontaneous ovarian failure and leads to life quality deterioration with various irritating symptoms. Hormonal treatment can alleviate these symptoms, but long-term treatment is closely associated with breast and uterine cancer, and stroke. Therefore, developing alternative therapies with novel anti-menopausal substances and improved safety is needed. In our study, heat-killed Bifidobacterium breve HDB7040 significantly promoted MCF-7 cell proliferation in a dose-dependent manner under estrogen-free conditions, similar to 17β-estradiol. This strain also triggered ESR2 expression, but not ESR1, in MCF-7 cells. Moreover, administrating HDB7040 to ovariectomized (OVX) Sprague-Dawley (SD) female rats reduced estrogen deficiency-induced weight gain, fat mass, blood triglyceride, and total cholesterol levels. It also recovered collapsed trabecular microstructure by improving trabecular morphometric parameters (bone mineral density, bone volume per tissue volume, trabecular number, and trabecular separation) and decreasing blood alkaline phosphatase levels with no significant changes in uterine size and blood estradiol. HDB7040 also significantly regulated the expression of Tff1, Pgr, and Esr2, but not Esr1 in uteri of OVX rats. Heat-killed B. breve HDB7040 exerts an anti-menopausal effect via the specific regulation of ERβ in vitro and in vivo, suggesting its potential as a novel substance for improving and treating menopausal syndrome.

• Korea-Australia Rheology Journal
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• v.21 no.1
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• pp.59-69
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• 2009

The prediction of pressure drop for a droplet flow in a confined micro channel is presented using FE-FTM (Finite Element - Front Tracking Method). A single droplet is passing through 5:1:5 contraction - straight narrow channel - expansion flow domain. The pressure drop is investigated especially when the droplet flows in the straight narrow channel. We explore the effects of droplet size, capillary number (Ca), viscosity ratio ($\chi$) between droplet and medium, and fluid elasticity represented by the Oldroyd-B constitutive model on the excess pressure drop (${\Delta}p^+$) against single phase flow. The tightly fitted droplets in the narrow channel are mainly considered in the range of $0.001{\leq}Ca{\leq}1$ and $0.01{\leq}{\chi}{\leq}100$. In Newtonian droplet/Newtonian medium, two characteristic features are observed. First, an approximate relation ${\Delta}p^+{\sim}{\chi}$ observed for ${\chi}{\geq}1$. The excess pressure drop necessary for droplet flow is roughly proportional to $\chi$. Second, ${\Delta}p^+$ seems inversely proportional to Ca, which is represented as ${\Delta}p^+{\sim}Ca^m$ with negative m irrespective of $\chi$. In addition, we observe that the film thickness (${\delta}_f$) between droplet interface and channel wall decreases with decreasing Ca, showing ${\delta}_f{\sim}Ca^n$ Can with positive n independent of $\chi$. Consequently, the excess pressure drop (${\Delta}p^+$) is strongly dependent on the film thickness (${\delta}_f$). The droplets larger than the channel width show enhancement of ${\Delta}p^+$, whereas the smaller droplets show no significant change in ${\Delta}p^+$. Also, the droplet deformation in the narrow channel is affected by the flow history of the contraction flow at the entrance region, but rather surprisingly ${\Delta}p^+$ is not affected by this flow history. Instead, ${\Delta}p^+$ is more dependent on ${\delta}_f$ irrespective of the droplet shape. As for the effect of fluid elasticity, an increase in ${\delta}_f$ induced by the normal stress difference in viscoelastic medium results in a drastic reduction of ${\Delta}p^+$.

• Proceedings of the Materials Research Society of Korea Conference
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• 2012.05a
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• pp.68.1-68.1
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• 2012

The best part of graphene is - charge-carriers in it are mass less particles which move in near relativistic speeds. Comparing to other materials, electrons in graphene travel much faster - at speeds of $10^8cm/s$. A graphene sheet is pure enough to ensure that electrons can travel a fair distance before colliding. Electronic devices few nanometers long that would be able to transmit charge at breath taking speeds for a fraction of power compared to present day CMOS transistors. Many researches try to check a possibility to make it a perfect replacement for silicon based devices. Graphene has shown high potential to be used as interconnects in the field of high frequency electrical devices. With all those advantages of graphene, we demonstrate characteristics of electrical and optical properties of graphene such as the effect of graphene geometry on the microwave properties using the measurements of S-parameter in range of 500 MHz - 40 GHz at room temperature condition. We confirm that impedance and resistance decrease with increasing the number of graphene layer and w/L ratio. This result shows proper geometry of graphene to be used as high frequency interconnects. This study also presents the optical properties of graphene oxide (GO), which were deposited in different substrate, or influenced by oxygen plasma, were confirmed using different characterization techniques. 4-6 layers of the polycrystalline GO layers, which were confirmed by High resolution transmission electron microscopy (HRTEM) and electron diffraction analysis, were shown short range order of crystallization by the substrate as well as interlayer effect with an increase in interplanar spacing, which can be attributed to the presence of oxygen functional groups on its layers. X-ray photoelectron Spectroscopy (XPS) and Raman spectroscopy confirms the presence of the $sp^2$ and $sp^3$ hybridization due to the disordered crystal structures of the carbon atoms results from oxidation, and Fourier Transform Infrared spectroscopy (FTIR) and XPS analysis shows the changes in oxygen functional groups with nature of substrate. Moreover, the photoluminescent (PL) peak emission wavelength varies with substrate and the broad energy level distribution produces excitation dependent PL emission in a broad wavelength ranging from 400 to 650 nm. The structural and optical properties of oxygen plasma treated GO films for possible optoelectronic applications were also investigated using various characterization techniques. HRTEM and electron diffraction analysis confirmed that the oxygen plasma treatment results short range order crystallization in GO films with an increase in interplanar spacing, which can be attributed to the presence of oxygen functional groups. In addition, Electron energy loss spectroscopy (EELS) and Raman spectroscopy confirms the presence of the $sp^2$ and $sp^3$ hybridization due to the disordered crystal structures of the carbon atoms results from oxidation and XPS analysis shows that epoxy pairs convert to more stable C=O and O-C=O groups with oxygen plasma treatment. The broad energy level distribution resulting from the broad size distribution of the $sp^2$ clusters produces excitation dependent PL emission in a broad wavelength range from 400 to 650 nm. Our results suggest that substrate influenced, or oxygen treatment GO has higher potential for future optoelectronic devices by its various optical properties and visible PL emission.

• Advances in nano research
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• v.10 no.2
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• pp.115-128
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• 2021

In this article, free vibration behavior of electro-magneto-thermo sandwich Timoshenko beam made of porous core and Graphene Platelet Reinforced Composite (GPLRC) in a thermal environment is investigated. The governing equations of motion are derived by using the modified strain gradient theory for micro structures and Hamilton's principle. The magneto electro are under linear function along the thickness that contains magnetic and electric constant potentials and a cosine function. The effects of material length scale parameters, temperature change, various distributions of porous, different distributions of graphene platelets and thickness ratio on the natural frequency of Timoshenko beam are analyzed. The results show that an increase in aspect ratio, the temperature change, and the thickness of GPL leads to reduce the natural frequency; while vice versa for porous coefficient, volume fractions and length of GPL. Moreover, the effect of different size-dependent theories such as CT, MCST and MSGT on the natural frequency is investigated. It reveals that MSGT and CT have most and lowest values of natural frequency, respectively, because MSGT leads to increase the stiffness of micro Timoshenko sandwich beam by considering three material length scale parameters. It is seen that by increasing porosity coefficient, the natural frequency increases because both stiffness and mass matrices decreases, but the effect of reduction of mass matrix is more than stiffness matrix. Considering the piezo magneto-electric layers lead to enhance the stiffness of a micro beam, thus the natural frequency increases. It can be seen that with increasing of the value of WGPL, the stiffness of microbeam increases. As a result, the value of natural frequency enhances. It is shown that in hc/h = 0.7, the natural frequency for WGPL = 0.05 is 8% and 14% less than its for WGPL = 0.06 and WGPL = 0.07, respectively. The results show that with an increment in the length and width of GPLs, the natural frequency increases because the stiffness of micro structures enhances and vice versa for thickness of GPLs. It can be seen that the natural frequency for aGPL = 25 ㎛ and hc/h = 0.6 is 0.3% and 1% more than the one for aGPL = 5 ㎛ and aGPL = 1 ㎛, respectively.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.49 no.4
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• pp.299-306
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• 2023

In this study, exosomes were isolated by ultrafiltration from Lactobacillus rhamnosus J2K-821 and their various effects for skin were evaluated. Their size and concentration were identified 50 ~ 200 nm and 3.22 × 10⁸ particles/mL, respectively through nanoparticle tracking analysis. In order to verify the inflammatory relief effect of Lactobacillus rhamnosus-derived exosomes (LRDEs), their nitric oxide (NO) production inhibitory ability in RAW 264.7 macrophages induced an inflammatory reaction with lipopolysaccharide (LPS) was confirmed. It was revealed that they inhibited NO production in a concentration-dependent manner. To evaluate the antioxidant activity and skin barrier improvement effect of LRDEs, their 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and hyaluronidase inhibitory activity were confirmed. It was also revealed that their activities were increased by concentration-dependent manner. Through these results, It is believed that LRDEs can be used as a effective natural cosmetic ingredient for anti-inflammation, antioxidation and skin barrier improvement.

• Journal of the Korean Geophysical Society
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• v.5 no.4
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• pp.305-319
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• 2002

The three-dimensional MT(Magneto-Telluric) modeling is performed to examine the validity of difference arrow of GDS(Geomagnetic Depth Sounding) survey, In this paper, we investigate the validity of the difference arrow on three configurations of conductors; which is located 1) at surface, 2) at the deep part and 3) vertically extended f개m surface to the deep part, respectively, For conductors located at surface, the validity of difference arrows is certified in our numerical model when long periods over 40 minutes are used or the distance between sea and conductor is over 150 km. However, for conductors located at the deep part, the validity of difference arrow is dependent on the size of conductors. Further, if the size of conductor is adequately larger than that of our model, we recognize the possibility that the mutual coupling of them influences up to longer periods, Moreover, in case of conductors which is vertically extended from surface to the deer part, the mutual coupling of them is reinforced for all periods, especially for longer periods, so that the validity of difference arrow is considerably in doubt. Therefore, to remove the known conductor effect such as the sea effect from the observed induction arrow, the mutual coupling between them must be examined. The difference arrow that certifies the validity in this way can only provide the Subsurface information based on physical supports.

• Korean Chemical Engineering Research
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• v.46 no.2
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• pp.330-339
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• 2008

Effect of additives such as NP series nonionic surfactant and cosurfactant on AgCl nanoparticles was investigated where nanoparticles were prepared using two different types of water-in-oil (W/O) microemulsions containing silver nitrate and sodium chloride, respectively. Phase behavior experiments showed that the region of one phase W/O microemulsion was found to be broadened with an increase in the ethylene oxide length of a nonionic surfactant mainly due to an increase in hydrophilic nature of a surfactant. Photomicrographs obtained by transmission electron microscopy indicated that an increase in ethylene oxide length of a nonionic surfactant results in both increases in particle size and size distribution. Phase behavior experiments for the systems containing AOT surfactant, isooctane and aqueous solution of an inorganic salt showed that addition of a cosurfactant caused a shrinkage in phase region of one phase W/O microemulsion, especially water contents contained in W/O microemulsion with an increase in the chain length or the concentration of a cosurfactant used. Photomicrographs obtained by transmission electron microscopy indicated that characteristics of AgCl nanoparticles produced were dependent both on the radius of spontaneous curvature and film rigidity of a microemulsion.

• Child Health Nursing Research
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• v.6 no.2
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• pp.119-131
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• 2000

The purpose of this study was to identify the trends and contents of intervention towards children using meta analysis, to support the basis for using in the field and research method about nursing intervention. We used 27 materials which was reported from 1970 to August, 1999 : dissertation study and Korean Nurses' Academic society Journals, the Journal of Korean Academic society of Adult Nursing, The Korea Journal of Maternal and Child Health Nursing. The types of intervention we used came from 3 different researchers. Snyder showed cognitive, movement, social sensory intervention. McCloskey & Bulechek categorized as the following : self-care assistance, acute care management, life-style alteration, health promotion, life support intervention, Craft & Denehy classified psychosocial intervention and biophysiological intervention. Some findings are summarized as follow : Out of the 27 researches sensory intervention had the most in there thesis, recently cognitive intervention research has a tendency to increase. 18 researches has acute care management in there theses, and health promotion was found the least. Out of the 27 thesis 15 thesis was classified as biophysiological intervention and 12 had psychosocial. 27 thesis had 11 types of interventions which originally was categorized by Snyder, therefore sensory intervention thesis had the most. 11 types of intervention which originally was classified by McClosky & Bulechek, teaching and information had the most out of acute care management. Out of 27 thesis, 14 had dealt with newborns, especially newborns with sensory intervention. Therefore school age and above had cognitive intervention which was used for teaching and information. Infants, preschool, schoolage children received acute care management the most, health promotion intervention was used towards adolescences. Depending on the characteristics of dependent variables, it was analysed using meta however 17 thesis are possible except primary experimental research. Mean effect size comparison by Snyder classification, cognitive intervention was the largest mean(1.51), sensory intervention was larger(0.71) also, movement intervention was in the middle(0.56) as shown. Comparison done by McClosky & Bulechek, the intervention leading to life style alteration was the largest mean(1.97), teaching was used the most. Comparison by Craft & Denehy classification, psychosocial intervention was larger(1.15) than biophysiological intervention (0.67). The result of nursing intervention through age classification, the largest weighted mean effect size in the research was towards infants and neonates. The research which was focused on nursing intervention, has important meaning in nursing practice and knowledge development. When we know that children's nursing intervention is necessary and overcome our biased view, efficiency of children's nursing intervention are increased and professionalized. Therefore results will be important basic data to guide a development of child nursing intervention & classification.

• Polymer(Korea)
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• v.32 no.6
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• pp.516-522
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• 2008

Biodegradable polymers have been used extensively as scaffolding materials to regenerate new tissues and the ingrowth of tissue have been reported to be dependent directly of the porosity, pore diameter, pore shape, and porous structure of the scaffold. In this study, porous poly (L-lactide-co-glycolide) (PLGA) scaffolds with five different pore sizes were fabricated to investigate the effect of pore sizes for AF tissue regeneration. Cellular viability and proliferation were assayed by MTT test. Hydroxyproline/DNA content of AF cells on each scaffold was measured. sGAG analyses were performed at each time point of 2 and 6 weeks. Scaffold seeded AF cells were implanted into the back of athymic nude mouse to observe the difference of formation of disc-like tissue depending on pore size in vivo. We confirmed that scaffold with $180{\sim}250{\mu}m$ pores displayed high cell viability in vitro and produced higher ECM than scaffold with other pore sizes in vivo.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.18 no.1
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• pp.225-236
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• 2023

Policy implications were derived by comparing/analyzing innovative SMEs and general SMEs that obtained innovation certification from 2015 to 2021 in terms of survival period. Work experience, scale (employment, capital and debt size, sales and operating profit) Korean standard industry classification (2 digit) was used to select general SMEs similar to innovative SMEs. Survival period was calculated by defining suspension, closure and overdue equivalent to default as events. As a result of the survival analysis, innovative SMEs showed a 9.8% reduction in the risk of delinquency compared to general SMEs, indicating that the survival period of innovative SMEs was significantly longer. In addition, it was found that the work experience and size (employment, capital) of SMEs had a positive effect on the survival period, but debt had a negative effect on the survival period. This means that the innovation certification system centered on innovation capabilities and future growth potential is a significant indicator in terms of survival period. As a result, it was concluded that the benefits and support policies provided by the innovation certification system need to be more systematic and sophisticated by reflecting the work experience and industry for the actual growth and survival of SMEs.