Thermal Behaviors of Nd₂Fe₁₄B / Fe₃B Based Nanocomposite Magnets

ChoongJin Yang,EonByung Park,SeungDuck Choi,Gao Youhui,Zhu JingHan 한국자기학회 1998 Journal of Magnetics Vol.3 No.1

Two different compositions of melt spun magnetic alloys, Nd₄Fe_(80)B_(16) and Nd₄Fe_(76)Co₃Hf_(0.5)Ga_(0.5)B_(16), were characterized in terms of magnetic properties and thermal behaviors. It was found that the addition of Hf and Ga effectively slow down the crystallization rate of the nanocomposite Nd₂Fe₁₄B/Fe₃B magnet. Coercivity(iHc) changes only slightly with varying the post annealing conditions confirming that iHc is not a sensitive magnetic quantity as a function of grain size and exchange coupled interaction. The experimentally observed behaviors of Mr and Hc do not vary monotonously with increasing grain size which is not in agreement with the numerically calculated result near the critical grain size(dc). The plot of the grain size dependence for the remanence and coercivity in isotrop!c nanocomposite magnets has been revised in this study. The maxium energy product, (B. H)max=15.34 MGOe, and a reduced remanence, Mr/Ms=0.84 were obtained, respectively.

Treatment of focal hyperhidrosis by the transdermally delivered myricetin

Choongjin BAN,Joon-Bum PARK,Sora CHO,Hye Rin KIM,Yong Joon KIM,Dae-Hyuk KWEON 한국생물공학회 2019 한국생물공학회 학술대회 Vol.2019 No.10

Transdermal delivery of myricetin for the hyperhidrosis treatment using lipid nanoparticles

Choongjin BAN,Joon-Bum PARK,Sora CHO,Hyerin KIM,Jonghyeok SHIN,Chakhee KIM,Hooyeon KIM,Yunjeong PARK,Myungseo PARK,Younghun JUNG,Seokoh MOON,Emine SEYDAMETOVA,Seok-Hyeon YU,Dae-Hyuk KWEON 한국생물공학회 2018 한국생물공학회 학술대회 Vol.2018 No.10

Improving Bioavailability of the Ingested Curcumin using PEGylated Lipid Nanoparticle System

Choongjin Ban,Seokwon Lim,Young Jin Choi 한국산업식품공학회 2016 학술대회 및 심포지엄 Vol.2016 No.10

To enhance the oral bioavailability (BA) of curcumin (CUR), we applied 1 wt% CUR-loaded lipid nanoparticle (LNP) system prepared with tristearin (TS) and short (Brij S10) / long (Brij S100) PEGylated surfactants. All LNPs were colloidally stable under high ion strength and pH 3 conditions regardless of the PEG chain length. However, the long-chained PEGylation prevented LNP surface better than the short-chained PEGylation from the lipase/bile salt adsorption according to ζ potential results after treatment of lipase and bile solutions. Actually, the short-chained LNPs were digested rapider than the long-chained one in the simulated small intestinal condition due to the faster displacement of PEGylated surfactants on LNP surface by bile salts. Furthermore in the rat model pharmacokinetics for oral administration of CUR, the long-chained LNP group had 10.62-fold BA of native CUR group due to the coabsorption of CUR with the mixed micelles made after gastrointestinal digestion, and had 4.57-fold BA of the short-chained LNP group despite the same molarity use (17.058 mM) of both emulsifiers due to the reduced digestion rate by long-chained PEG on LNP surface. In conclusion, since CUR incorporated in LNPs was improved in the bioavailability, the designed LNP system may serve as an encapsulation strategy to enhance the bioavailability of non-bioavailable nutraceuticals in foods.

THE EFFECT OF HfB₂ ON MAGNETIC PROPERTIES OF NANOCOMPOSITE Fe₂Nd₁₄B / Fe₃B MAGNET

ChoongJin Yang,ChanWook Kim,EyunByung Park 한국자기학회 1995 韓國磁氣學會誌 Vol.5 No.5

By adding lwt.% HfB₂ into Nd_(3-4)Fe_(77-78.5)B_(18.5) alloys, the grain growth of Fe₃B/Nd₂Fe₁₄B composite phases during annealing was found to be hindered by 40~50%. It is proposed that the addition of HfB₂ leads to the formation of fine dispersoids of HfB₂ in the Fe₃B/Nd₂Fe₁₄B composite magnet. The maximum energy product((B.H)max) as well as intrinsic coercivity(iHc) for the Nd₃Fe_(78.5)B_(18.5)+lwt.% HfB₂ alloy were enhanced by more than 25% (B.H)max=10 MGOe, iHc=2.5 kOe) due to the addition of HfB₂ while remanent magntization(Br) was reduced slightly. It is deduced that the formation of fine dispersoids will also play a role of magnetic domain pinning.

Enhancing the Stability of Lipid Nanoparticle Systems by Sonication during the Cooling Step and Controlling the Liquid Oil Content

Ban, Choongjin,Lim, Seokwon,Chang, Pahn-Shick,Choi, Young Jin American Chemical Society 2014 Journal of agricultural and food chemistry Vol.62 No.47

<P>Aggregation of unstable particles in water limits the application of lipid nanoparticle (LNP) systems to foods despite the capability to encapsulate lipophilic bioactive components. This study exploits a preparation process that can reduce the aggregation of LNPs. Sonication during the cooling step (postsonication) for 4, 5, or 6 min was applied to increase the covering effect of Tween 20 on the particle. Additionally, LNPs were prepared using fully hydrogenated canola oil (FHCO) blended with 0–30 wt % liquid canola oil (LCO) of the lipid phase. Surfactant surface load data indicate that the postsonication might make nonemulsifying Tween 20 diffuse from the aqueous phase to droplet surfaces, which could decrease the crystallinity index (CI) of LNPs due to the inhibition of lipid crystallization. Moreover, the LCO content in lipid matrix could decrease the CI, which could reduce the formation of hydrophobic patches on the particle surface. Therefore, the postsonication and the LCO addition in the matrix could effectively prevent aggregation among hydrophobic patches. This improved colloidal stability of LNPs was verified by the particle shape in transmission electron microscopy and the gelation test. Consequently, LNPs fabricated using 6 min postsonication and 30 wt % LCO in the lipid exhibited the greatest stability (size, 202.3 nm; CI, 57.5%; Tween 20 surface load, 10.29 mg m<SUP>–2</SUP>). This study may serve as a basis for further research that aims to develop delivery systems for functional foods.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jafcau/2014/jafcau.2014.62.issue-47/jf503489v/production/images/medium/jf-2014-03489v_0007.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/jf503489v'>ACS Electronic Supporting Info</A></P>

Improving Flavonoid Bioaccessibility using an Edible Oil-Based Lipid Nanoparticle for Oral Delivery

Ban, Choongjin,Park, So Jeong,Lim, Seokwon,Choi, Seung Jun,Choi, Young Jin American Chemical Society 2015 Journal of agricultural and food chemistry Vol.63 No.21

<P>To enhance the oral bioaccessibility of flavonoids, including quercetin, naringenin, and hesperetin, we prepared an edible oil-based lipid nanoparticle (LNP) system. Flavonoid-loaded LNPs were similar to the blank LNP in physicochemical characteristics (<I>z</I> average <154.8 nm, polydispersity index <0.17, and ζ potential < −40.8 mV), and their entrapment efficiency was >81% at 0.3 wt % flavonoid concentration of the lipid phase. In the simulated digestion assay (mouth, stomach, and small intestine), LNPs were hydrolyzed under small intestine conditions and protected successfully incorporated flavonoids (≥94%). Moreover, the relative bioaccessibility of flavonoids was >71%, which was otherwise <15%, although flavonoids were released rapidly from LNPs into the medium. In conclusion, since the flavonoids incorporated in LNPs were preserved well during oral digestion and had improved bioaccessibility, the designed LNP system may serve as an encapsulation strategy to enhance the bioavailability of nonbioaccessible nutraceuticals in foods.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jafcau/2015/jafcau.2015.63.issue-21/acs.jafc.5b01495/production/images/medium/jf-2015-014953_0003.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/jf5b01495'>ACS Electronic Supporting Info</A></P>

Control of the gastrointestinal digestion of solid lipid nanoparticles using PEGylated emulsifiers

Ban, Choongjin,Jo, Myeongsu,Lim, Seokwon,Choi, Young Jin Applied Science Publishers 2018 Food chemistry Vol.239 No.-

<P><B>Abstract</B></P> <P>We prepared solid lipid nanoparticles (SLNs) with tristearin and various emulsifiers which had different chain length PEGs (10–100 times-repetition of ethylene glycol) to control their digestion fate in the gastrointestinal tract. Fabricated SLNs after acidic/high-ionic-strength media treatment were stable regardless of the ζ-potential (ZP) disappearance. Additionally, highly PEGylated SLNs successfully hindered the adsorption of both bile acid (BA) and lipase on the SLN surface, while lowly PEGylated SLNs interrupted that of only lipase. In simulated small intestinal fluid, lipolysis of highly PEGylated SLNs increased with decrease of the emulsifier density on the SLNs, whereas lipolysis of lowly PEGylated SLNs increased with decrease of the particle size. These results suggested that high PEGylation was more efficient than low PEGylation to hinder the lipolysis initiated from the competitive replacement of the SLN-covering emulsifiers with BAs. Consequently, the SLN digestion could be controlled by choosing the length and concentration of PEGylated emulsifiers.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Saturation of PEGylated emulsifiers onto SLNs was determined by the lipophilic tail. </LI> <LI> Larger and denser PEG molecules on SLNs better inhibit the adsorption of bile acids. </LI> <LI> Lipolysable degree of small PEGylated SLNs was inversely proportional to the size. </LI> <LI> Lipolysable degree of highly PEGylated SLNs was proportional to the PEG density. </LI> </UL> </P>

제과제빵류 냉동 기술의 신기술과 동향

반충진(Choongjin Ban),최영진(Young Jin Choi) 한국식품과학회 2012 식품과학과 산업 Vol.45 No.4

Effects of freezing rate and terminal freezing temperature on frozen croissant dough quality

Ban, Choongjin,Yoon, Sangeun,Han, Jungwoo,Kim, Sang Oh,Han, Jung Sook,Lim, Seokwon,Choi, Young Jin ACADEMIC PRESS - JOURNALS DEPARTMENT 2016 FOOD SCIENCE AND TECHNOLOGY -ZURICH- Vol.73 No.-

<P><B>Abstract</B></P> <P>Using frozen ready-to-bake dough is a very common practice in the industrial croissant production. However, the freezing process during the preparation frozen croissant dough can deteriorate its quality. In this study, we investigated the effects of the freezing rate (FR) and terminal freezing temperatures on the volume and firmness of croissants by analyzing frozen dough for yeast viability, thermal property changes, and internal microstructure integrity. Croissant dough samples were frozen at rates ranging from −0.72 to −3.56 °C min<SUP>−1</SUP> down to final temperatures of −20, −40, and −55 °C. Our results showed that the ice crystals normally forming in the dough during freezing, causing a lower yeast viability and croissants quality, were of smaller size when a rapid FR ≥ −3.19 °C min<SUP>−1</SUP> was used. Furthermore, a freezing termination temperature lower than −20 °C induced more yeast cell death, thereby deteriorating croissant quality. Therefore, we suggest that the croissant dough freezing process should be conducted with an appropriate FR down to a suitable terminal temperature. Consequently, our results are helpful to understand how the freezing procedure affects ice crystal formation and yeast viability in the frozen dough matrix and our findings can be applied to enhance bread quality in the frozen dough industry.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The optimal freezing rate for croissant dough was −3.19 °C min<SUP>−1</SUP>. </LI> <LI> The optimal terminal freezing temperature for croissant dough was −20 °C. </LI> <LI> At the optimal freezing conditions, frozen croissant dough had maximum viable yeasts. </LI> </UL> </P>