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Anatase TiO<sub>2</sub> nanosheets with surface acid sites for Friedel-Crafts alkylation
Lee, M.,Seo, Y.,Shin, H.S.,Jo, C.,Ryoo, R. Elsevier 2016 Microporous and mesoporous materials Vol.222 No.-
<P>The solvothermal synthesis route to mesoporous TiO2 using a vinylphenol polymer structure-directing agent (SDA) was optimized to provide a high yield of bilayer nanosheets. The resultant TiO2 material exhibited a high BET area of 420 m(2) g(-1) after the removal of SDA. Structural analysis of the nanosheets was carried out using powder X-ray diffraction, high resolution-transmission electron microscopy, Raman spectroscopy and solid-state NMR. The results indicated that the TiO2 material consisted mainly of the bilayer nanosheets with (010) facet-dominant anatase crystal structure. The thickness of the nanosheet was 0.75 nm, corresponding to two unit-cell parameters along the b-axis in the anatase crystal system. More than 10% of the surface Ti atoms were terminated with bridging O-H groups and coordinatively unsaturated Ti atoms, which acted as Bronsted and Lewis acid sites. Accordingly, the anatase nanosheets exhibited catalytic performance in the liquid-phase Friedel Crafts alkylation of aromatic compounds. (C) 2015 Elsevier Inc. All rights reserved.</P>
Insight from early coral-stromatoporoid intergrowth, Late Ordovician of China
Lee, M.,Elias, R.J.,Choh, S.J.,Lee, D.J. Elsevier 2016 Palaeogeography, palaeoclimatology, palaeoecology Vol.463 No.-
One of the earliest endosymbiotic associations with stromatoporoids occurs in the Late Ordovician Xiazhen Formation of southeastern China. Bajgolia, an auloporid tabulate coral characterized by dichotomous branching due to longitudinal fission, is represented by free-living as well as endobiontic forms in various lithofacies representing a wide range of environments. Only two of 11 stromatoporoid genera (Clathrodictyon and Ecclimadictyon) hosted Bajgolia, mainly in reef and related facies. Bajgolia-stromatoporoid associations occur occasionally in the lower part of the formation, but eventually become persistent in the upper part. Such associations were initiated by larval settlement of the coral on the growth surface of the stromatoporoid. Growth of Bajgolia usually kept pace with its host, but the coral's ability to change growth direction and grow faster prevented its envelopment and termination by the stromatoporoid, allowing the establishment and recurrence of an ongoing endosymbiotic relationship between the two organisms. Endobiontic Bajgolia was able to survive with its corallites protruding from the host; in some cases, the growth form of the stromatoporoid changed in response to the coral. The relationships between Bajgolia and stromatoporoids were probably commensal, but there is also evidence for mutualism and/or parasitism. Bajgolia-stromatoporoid associations represent an important stage in the development of complex ecological relationships and community structure, prior to the common and widespread syringoporid (''caunopore tubes'')-stromatoporoid associations in the Siluro-Devonian.
Lee, M.,Hwang, Y.K.,Chang, J.S.,Chae, H.J.,Hwang, D.W. Elsevier 2016 CATALYSIS COMMUNICATIONS - Vol.84 No.-
A Ni-Cu-SiO<SUB>2</SUB> nanocomposite was studied as a catalyst for vapor-phase glycerol hydrogenation to produce 1,2-propanediol (1,2-PDO). Substitution of a small amount (3wt%) of Ni for Cu is beneficial for decreasing the Cu particle size, which would be advantageous for attaining higher 1,2-PDO selectivity and higher glycerol conversion. 92% 1,2-PDO selectivity and 100% glycerol conversion were obtained at 220<SUP>o</SUP>C, 30bar, and a weight hourly space velocity of 0.5h<SUP>-1</SUP> over Ni(3)-Cu(77)-SiO<SUB>2,</SUB> which were nearly identical to those obtained with the conventional copper chromite (CuO-Cr<SUB>2</SUB>O<SUB>3</SUB>) catalyst. Therefore, the present Ni(3)-Cu(77)-SiO<SUB>2</SUB> nanocomposite is regarded as a green and efficient catalyst for glycerol conversion into more valuable 1,2-PDO.
Lee, M.,Jang, Y.,Kim, K.,Cho, H.,Jee, S.h.,Park, Y.,Kim, M.K. Elsevier Scientific Publ. Co 2010 Atherosclerosis Vol.213 No.1
Objective: Limited information is available on the association of HDL subtypes and the risk of metabolic syndrome (MetSyn). The objective of the present study was to investigate the association of HDL subspecies with the prevalence of MetSyn in new outpatients. Methods: Five hundred forty-one new outpatients (366 males and 175 females) were enrolled in two hospitals participating in the KMSRI-Seoul Study. The new criteria for the Korean MetSyn based on the 2005 KHANES were used. Medical questionnaires, anthropometric measurements, 3-day recall dietary assessments, and blood biomarker analyses were performed. Unconditional logistic regression models were used to estimate crude and odds ratios (ORs) and 95% confidence intervals (CIs) with multivariate adjustments. The proportions of HDL subtypes were measured after subtypes were identified by 4-30% gradient gel electrophoresis. Results: Of the subjects, 50.8% were classified as MetSyn; blood pressure (BP) and fasting blood sugar (FBS) among the five criteria did not differ by gender. Increasing the HDL<SUB>2b</SUB> subtype significantly reduced the risk of MetSyn in males and females. The association of small size HDL<SUB>3b</SUB> with the risk of MetSyn was stronger in females than in males: adjusted ORs (95% CIs) for the 3rd tertile of HDL<SUB>3b</SUB> compared to the 1st tertile were 3.79 (CI, 2.00-7.18) in males and 11.2 (CI, 2.1-59.6) in females. However, a decreased waist circumference (WC), BP, and triglycerides (TG) were observed with increased large HDL particles in males. Conclusions: Small-sized HDL was associated with increased MetSyn risk factors and closely related to WC, BP, TG, and HOMA-IR, particularly in males.
Adipose-derived stem cell exosomes alleviate pathology of amyotrophic lateral sclerosis in vitro
Lee, M.,Ban, J.J.,Kim, K.Y.,Jeon, G.S.,Im, W.,Sung, J.J.,Kim, M. Academic Press 2016 Biochemical and biophysical research communication Vol.479 No.3
Amyotrophic lateral sclerosis (ALS) is a degenerative disorder that involves the death of motor neurons in the cortex, brain stem, and spinal cord. Adipose-derived stem cells (ADSCs) are considered as a perspective remedy for therapy of neurodegenerative diseases including ALS. Stem cells secrete various factors which can modulate a hostile environment, called paracrine effect. Exosomes are small extracellular vesicles containing cell derived factors and mediate paracrine effect of cells. Thus, exosomes from ADSCs (ADSC-exo) can be a potential candidate of therapeutic effects of stem cells. To investigate the effect of ADSC-exo on the cellular phenotypes of ALS, we used neuronal stem cells (NSCs), which can be differentiated into neuronal cells, isolated from wild type or G93A ALS mice model. ADSC-exo was treated to neuronal cells from G93A ALS mice model. Immunocytochemistry and dot-blot assay result showed that ADSC-exo alleviated aggregation of superoxide dismutase 1 (SOD1). Reduction of cytosolic SOD1 level by ADSC-exo was also confirmed by western blot. Mitochondria display various abnormalities in ALS and the decrease of phospho-CREB and PGC-1α were observed in the G93A cells. ADSC-exo treatment showed normalization of phospho-CREB/CREB ratio and PGC-1α expression level. Our results suggest that ADSC-exo modulates cellular phenotypes of ALS including SOD-1 aggregation and mitochondrial dysfunction, and can be a therapeutic candidate for ALS.
Lee, M.,Lee, S. Elsevier 2017 Technological forecasting social change Vol.119 No.-
This study aims to analyze the position of technology-centered companies in complex market dynamics and discover new business opportunities from competitor intelligence. For this, we consider both technology and market characteristics in providing competitor intelligence by utilizing patent data as a representative proxy for a firm's technology, and trademark data as an information source for the firm's target goods and services. To analyze the two types of data, a collaborative filtering approach together with portfolio analyses and association mining techniques were adopted. Theoretically, this is one of the earliest attempts to combine patent data and trademark data to investigate corporate strategies. In practice, the research results are expected to be used as a decision criterion to diagnose the economic value that companies can obtain by entering the market, as well as the technological value to be passed onto their customers. Thus, the proposed approach can be useful to support effective technology and business strategies in a firm.