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Enhanced enzymatic hydrolysis of kenaf core using irradiation and dilute acid
Lee, B.M.,Jeun, J.P.,Kang, P.H. Pergamon 2017 Radiation physics and chemistry Vol.130 No.-
<P>This study was performed to determine the effect of electron beam dose and enzymatic hydrolysis time for production of sugar such as glucose and xylose. After kenaf core was exposed to an irradiation dose that ranged from 0 to 500 kGy, the irradiated kenaf core was treated with a 3% (v/v) sulfuric acid solution using an autoclave for 5 h at 120 degrees C. The pretreated kenaf core was subsequently subjected to enzymatic hydrolysis at 50 degrees C in a shaking water bath at 150 rpm for 12, 24, 48, and 72 h. The determined enzyme activity rates were 70 FPU (Celluclast 1.5 L) and 40 CBU (Novozyme-188). The crystallinity index decreased from 50.6% in a non-pretreated kenaf core to 27.7% in kenaf core that was subjected to the two stage pretreatment at dose of 500 kGy. The sugar yield of the two-stage pretreated kenaf core increased with an increase in irradiation dose. The sugar yield after 72 h of enzymatic hydrolysis was 73.6% at its highest with an irradiation dose of 500 kGy. The enhancement of enzymatic hydrolysis by two-stage pretreatment was more effective than non-and single pretreatment (36.9%, 40.6% and 44.0% in non pretreatment, electron beam and dilute acid, respectively). (C) 2016 Elsevier Ltd. All rights reserved.</P>
Isolation and characterization of nanocrystalline cellulose from different precursor materials
Lee, B. M.,Jeun, J. P.,Kang, P. H.,Choi, J. H.,Hong, S. K. THE KOREAN FIBER SOCIETY 2017 Fibers and polymers Vol.18 No.2
<P>Nanocrytalline cellulose (NCC) was isolated using cellulose extracted from two different precursor materials: Eucalyptus globulus and rice straw. The two ground precursor materials were autoclaved with a 10 % NaOH solution at 120 degrees C for 3 h. The alkali-treated precursor materials were bleached using sodium chlorite/acetic acid and sodium hypochlorite. The bleached precursor materials were acid-hydrolyzed in 65 % (w/w) sulfuric acid at 45 degrees C for 30-120 min. The changes in the chemical composition of the two precursor materials were studied before and after bleaching by Fourier transform infrared spectroscopy according to the NREL report and TAPPI standards. Hydrolyzates were characterized by Xray diffractometry, thermogravimetric analysis, Zeta-potential analysis, and transmission electron microscopy. The results revealed that the physical properties of NCC were strongly dependent on the acid-hydrolysis time.</P>
스퍼터링한 반금속 Bi 박막의 미세조직과 자기저항특성에 미치는 후열처리의 영향
전민홍,장준연,한석희,한준현,이우영 대한금속재료학회 2004 대한금속·재료학회지 Vol.42 No.7
We explore the possibility of sputtered Bi thin film applicable for the spin device by investigating the change in microstructure and magneto-resistance (MR) of post-annealed Bi film. Randomly oriented fine grains of which size was measured to about 100 nm (nano meter) were found in as-sputtered Bi. Careful annealing done at only 1.4℃ below the melting temperature of Bi results in not only grain growth up to 1.2 pm but also textured grains well aligned to [003] preferred orientation of Bi. The MR for as-sputtered Bi film was hardly observed regardless of measuring temperature, whereas those of annealed were found to reach 30,000% at 4 K and 600% at 300 K respectively. The drastic change in MR after annealing is largely attributed to the significant grain growth decreasing grain boundary scattering as well as to the trigonal-axis oriented microstructures diminishing anisotropy scattering of moving electron. Our results demonstrate sputtered Bi thin film can be usable for spintronic devices by employing a suitable post annealing treatment. (Received March 29, 2004)
Gut-Specific Delivery of T-Helper 17 Cells Reduces Obesity and Insulin Resistance in Mice
Hong, C.P.,Park, A.,Yang, B.G.,Yun, C.H.,Kwak, M.J.,Lee, G.W.,Kim, J.H.,Jang, M.S.,Lee, E.J.,Jeun, E.J.,You, G.,Kim, K.S.,Choi, Y.,Park, J.H.,Hwang, D.,Im, S.H.,Kim, J.F.,Kim, Y.K.,Seoh, J.Y.,Surh, C. Elsevier North Holland [etc.] 2017 Gastroenterology Vol.152 No.8
<P>BACKGROUND & AIMS: Obesity and metabolic syndrome have been associated with alterations to the intestinal microbiota. However, few studies examined the effects of obesity on the intestinal immune system. We investigated changes in subsets of intestinal CD4(+) T-helper (T-H) cells with obesity and the effects of gut-tropic T(H)17 cells in mice on a high-fat diet (HFD). METHODS: We isolated immune cells from small intestine and adipose tissue of C57BL/6 mice fed a normal chow diet or a HFD for 10 weeks and analyzed the cells by flow cytometry. Mice fed a vitamin A-deficient HFD were compared with mice fed a vitamin A-sufficient HFD. Obese RAG1-deficient mice were given injections of only regulatory T cells or a combination of regulatory T cells and T(H)17 cells (wild type or deficient in integrin beta 7 subunit or interleukin 17 [IL17]). Mice were examined for weight gain, fat mass, fatty liver, glucose tolerance, and insulin resistance. Fecal samples were collected before and after T cell transfer and analyzed for microbiota composition by metagenomic DNA sequencing and quantitative polymerase chain reaction. RESULTS: Mice placed on a HFD became obese, which affected the distribution of small intestinal CD4(+) T-H cells. Intestinal tissues from obese mice had significant reductions in the proportion of T(H)17 cells but increased proportion of T(H)1 cells, compared with intestinal tissues from nonobese mice. Depletion of vitamin A in obese mice further reduced the proportion of T(H)17 cells in small intestine; this reduction correlated with more weight gain and worsening of glucose intolerance and insulin resistance. Adoptive transfer of in vitro-differentiated gut-tropic T(H)17 cells to obese mice reduced these metabolic defects, which required the integrin beta 7 subunit and IL17. Delivery of T(H)17 cells to intestines of mice led to expansion of commensal microbes associated with leanness. CONCLUSIONS: In mice, intestinal T(H)17 cells contribute to development of a microbiota that maintains metabolic homeostasis, via IL17. Gut-homing T(H)17 cells might be used to reduce metabolic disorders in obese individuals.</P>
Park, S-H,Doh, J,Park, S I,Lim, J Y,Kim, S M,Youn, J-I,Jin, H-T,Seo, S-H,Song, M-Y,Sung, S Y,Kim, M,Hwang, S J,Choi, J-M,Lee, S-K,Lee, H Y,Lim, C L,Chung, Y J,Yang, D,Kim, H-N,Lee, Z H,Choi, K Y,Jeun, Macmillan Publishers Limited 2010 Gene Therapy Vol.17 No.8
Cell-permeable peptides (CPPs) promote the transduction of nonpermissive cells by recombinant adenovirus (rAd) to improve the therapeutic efficacy of rAd. In this study, branched oligomerization of CPPs significantly enhanced the transduction of human mesenchymal stem cells (MSCs) by rAd in a CPP type-independent manner. In particular, tetrameric CPPs increased transduction efficiency at 3000–5000-fold lower concentrations than did monomeric CPPs. Although branched oligomerization of CPPs also increases cytotoxicity, optimal concentrations of tetrameric CPPs required for maximum transduction are at least 300–1000-fold lower than those causing 50% cytotoxicity. Furthermore, although only ∼60% of MSCs were maximally transduced at 500 μM of monomeric CPPs, >95% of MSCs were transduced with 0.1 μM of tetrameric CPPs. Tetrameric CPPs also significantly increased the formation and net surface charge of CPP/rAd complexes, as well as the binding of rAd to cell membranes at a greater degree than did monomeric CPPs, followed by rapid internalization into MSCs. In a critical-size calvarial defect model, the inclusion of tetrameric CPPs in ex vivo transduction of rAd expressing bone morphogenetic protein 2 into MSCs promoted highly mineralized bone formation. In addition, MSCs that were transduced with rAd expressing brain-derived neurotrophic factor in the presence of tetrameric CPPs improved functional recovery in a spinal cord injury model. These results demonstrated the potential for tetrameric CPPs to provide an innovative tool for MSC-based gene therapy and for in vitro gene delivery to MSCs.