Dynamic biomaterials for mechanobiology

Yu Suk Choi(최유석),William J Hadden,Jennifer L Young,Andrew W Holle,Joachim Spatz,Adam Engler 한국고분자학회 2019 한국고분자학회 학술대회 연구논문 초록집 Vol.44 No.1

Ribotoxic Stress through p38 Mitogen-activated Protein Kinase Activates <i>in Vitro</i> the Human Pyrin Inflammasome

Yu, Je-Wook,Farias, Andrew,Hwang, Inhwa,Fernandes-Alnemri, Teresa,Alnemri, Emad S. American Society for Biochemistry and Molecular Bi 2013 The Journal of biological chemistry Vol.288 No.16

<P>Human pyrin with gain-of-function mutations in its B30.2/SPRY domain causes the autoinflammatory disease familial Mediterranean fever by assembling an ASC-dependent inflammasome that activates caspase-1. Wild-type human pyrin can also form an inflammasome complex with ASC after engagement by autoinflammatory PSTPIP1 mutants. How the pyrin inflammasome is activated in the absence of disease-associated mutations is not yet known. We report here that ribotoxic stress triggers the assembly of the human pyrin inflammasome, leading to ASC oligomerization and caspase-1 activation in THP-1 macrophages and in a 293T cell line stably reconstituted with components of the pyrin inflammasome. Knockdown of pyrin and selective inhibition of p38 MAPK greatly attenuated caspase-1 activation by ribotoxic stress, whereas expression of the conditional mutant ΔMEKK3:ER* allowed the activation of caspase-1 without ribotoxic stress. Disruption of microtubules by colchicine also inhibited pyrin inflammasome activation by ribotoxic stress. Together, our results indicate that ribotoxic stress activates the human pyrin inflammasome through a mechanism that requires p38 MAPK signaling and microtubule stability.</P>

Polar aprotic solvent-water mixture as the medium for catalytic production of hydroxymethylfurfural (HMF) from bread waste

Yu, Iris K.M.,Tsang, Daniel C.W.,Chen, Season S.,Wang, Lei,Hunt, Andrew J.,Sherwood, James,De Oliveira Vigier, Karine,Jé,rô,me, Franç,ois,Ok, Yong Sik,Poon, Chi Sun Elsevier 2017 Bioresource technology Vol.245 No.1

<P><B>Abstract</B></P> <P>Valorisation of bread waste for hydroxymethylfurfural (HMF) synthesis was examined in dimethyl sulfoxide (DMSO)-, tetrahydrofuran (THF)-, acetonitrile (ACN)-, and acetone-water (1:1v/v), under heating at 140°C with SnCl<SUB>4</SUB> as the catalyst. The overall rate of the process was the fastest in ACN/H<SUB>2</SUB>O and acetone/H<SUB>2</SUB>O, followed by DMSO/H<SUB>2</SUB>O and THF/H<SUB>2</SUB>O due to the rate-limiting glucose isomerisation. However, the formation of levulinic acid (via rehydration) and humins (via polymerisation) was more significant in ACN/H<SUB>2</SUB>O and acetone/H<SUB>2</SUB>O. The constant HMF maxima (26–27mol%) in ACN/H<SUB>2</SUB>O, acetone/H<SUB>2</SUB>O, and DMSO/H<SUB>2</SUB>O indicated that the rates of desirable reactions (starch hydrolysis, glucose isomerisation, and fructose dehydration) relative to undesirable pathways (HMF rehydration and polymerisation) were comparable among these mediums. They also demonstrated higher selectivity towards HMF production over the side reactions than THF/H<SUB>2</SUB>O. This study differentiated the effects of polar aprotic solvent-water mediums on simultaneous pathways during biomass conversion.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Bread waste was valorised for the synthesis of HMF, with yields of 26–27mol%. </LI> <LI> Fastest HMF production took place in ACN/H<SUB>2</SUB>O and acetonitrile/H<SUB>2</SUB>O systems. </LI> <LI> Slow glucose isomerization hindered HMF formation in DMSO/H<SUB>2</SUB>O and THF/H<SUB>2</SUB>O. </LI> <LI> Similar HMF selectivity was achieved in ACN/H<SUB>2</SUB>O, acetonitrile/H<SUB>2</SUB>O, and DMSO/H<SUB>2</SUB>O. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Limited value of diffusion-weighted MR imaging for differentiating bland from malignant portal venous thrombi.

Yu, Jeong-Sik,Chung, Jae-Joon,Kim, Joo Hee,Kim, Ki Whang,Catalano, Onofrio A,Choy, Garry,Zhu, Andrew,Hahn, Peter F,Sahani, Dushyant V Radiological Society of North America 2010 Radiology Vol.256 No.2

Wafer-scale synthesis of monolayer two-dimensional porphyrin polymers for hybrid superlattices

Zhong, Yu,Cheng, Baorui,Park, Chibeom,Ray, Ariana,Brown, Sarah,Mujid, Fauzia,Lee, Jae-Ung,Zhou, Hua,Suh, Joonki,Lee, Kan-Heng,Mannix, Andrew J.,Kang, Kibum,Sibener, S. J.,Muller, David A.,Park, Jiwoon American Association for the Advancement of Scienc 2019 Science Vol.366 No.6471

<P><B>Single-layer porphyrin polymerization</B></P><P>Two-dimensional polymers can be made as monolayer sheets through controlled synthesis at an interface. However, it is often difficult to create intact sheets over large areas that can be transferred onto substrates. Zhong <I>et al.</I> polymerized derivatized porphyrin molecules during laminar flow at a sharp pentane-water interface to form sheets that are 5 centimeters in diameter (see the Perspective by MacLean and Rosei). The authors used electron microscopy and spectroscopy to confirm that they had produced intact monolayers. These films were then transferred onto monolayer sheets of molybdenum disulfide to form superlattices for use as capacitors.</P><P><I>Science</I>, this issue p. 1379; see also p. 1308</P><P>The large-scale synthesis of high-quality thin films with extensive tunability derived from molecular building blocks will advance the development of artificial solids with designed functionalities. We report the synthesis of two-dimensional (2D) porphyrin polymer films with wafer-scale homogeneity in the ultimate limit of monolayer thickness by growing films at a sharp pentane/water interface, which allows the fabrication of their hybrid superlattices. Laminar assembly polymerization of porphyrin monomers could form monolayers of metal-organic frameworks with Cu<SUP>2+</SUP> linkers or covalent organic frameworks with terephthalaldehyde linkers. Both the lattice structures and optical properties of these 2D films were directly controlled by the molecular monomers and polymerization chemistries. The 2D polymers were used to fabricate arrays of hybrid superlattices with molybdenum disulfide that could be used in electrical capacitors.</P>

Fe\MgO\Cu-Phthalocyanine 복합구조 계면구조와 그 전자기적 특성

배유정(Yu Jeong Bae),이년종(Nyun Jong Lee),김태희(Tae Hee Kim),Andrew Pratt 한국자기학회 2013 韓國磁氣學會誌 Vol.23 No.6

The influence of insertion of an ultra-thin Cu-Phthalocyanine (CuPc) between MgO barrier and ferromagnetic layer in magnetic tunnel juctions (MTJs) was investigated. In order to understand the relation between the electronic and structural properties of Fe\MgO\CuPc, the surface (or interface) analysis was carried out systematically by using spin polarized metastable He de-excited spectroscopy for the CuPc films grown on the Si(001)\5 nm MgO(001)\7 nm Fe(001)\1.6 nm MgO(001) multilayer structure as the thickness of CuPc increases from 0 to 5 nm. In particular, for the 1.6 nm CuPc surface, a rather strong spin asymmetry between upand down-spin band appears while it becomes weaker or disappears for the CuPc films thinner or thicker than ~1.6 nm. Our results emphasize the importance of the interfacial electronic properties of organic layers in the spin transport of the hybrid MTJs.

Anionic Polymerization of Oxadiazole-Containing 2-Vinylpyridine by Precisely Tuning Nucleophilicity and the Polyelectrolyte Characteristics of the Resulting Polymers

Goodwin, Andrew,Goodwin, Kimberly M.,Wang, Weiyu,Yu, Yong-Guen,Lee, Jae-Suk,Mahurin, Shannon M.,Dai, Sheng,Mays, Jimmy W.,Kang, Nam-Goo American Chemical Society 2016 Macromolecules Vol.49 No.17

<P>Anionic polymerization is one of the most powerful techniques for preparation of well-defined polymers. However, this well-known and widely employed polymerization technique encounters major limitations for the polymerization of functional monomers containing heteroatoms. This work presents the anionic polymerization of 2-phenyl-5-(6-vinylpyridin-3-yl)-1,3,4-oxadiazole (VPyOzP), a heteroatom monomer that contains both oxadiazole and pyridine substituents within the same pendant group, using various initiating systems based on diphenylmethyl potassium (DPM-K) and triphenylmethyl potassium (TPM-K). Remarkably, well-defined poly(2-phenyl-5-(6-vinylpyridin-3-yl)-1,3,4-oxadiazole) (PVPyOzP) polymers having predicted molecular weights (MW) ranging from 2200 to 21 100 g/mol and polydispersity indices (PDI) ranging from 1.11 to 1.15 were prepared with TPM-K, without any additional additives, at -78 degrees C. The effect of temperature on the polymerization of PVPyOzP was also studied at -78, -45, 0, and 25 degrees C, and it was observed that increasing the polymerization temperature produced materials with unpredictable MWs and broader molecular weight distributions. Furthermore, the nucleophilicity of PVPyOzP was investigated through copolymerization with methyl methacrylate and acrylonitrile, where only living poly(methyl methacrylate) (PMMA) prepared by DPM-K/VPPy and in the absence of additives such as lithium chloride (LiCl) and diethyl zinc (ZnEt2) could be used to produce the well-defined block copolymer of PMMA-b-PVPyOzP. It was also demonstrated by sequential monomer addition that the nucleophilicity of living PVPyOzP is located between that of living PMMA and polyacrylonitrile (PAN). The pyridine moiety of the pendant group also allowed for quaternization and produced PQVPyOzP homopolymer using methyl iodide (CH3I) and bis(trifluoromethylsulfonyl)amide [Tf2N ]. The resulting charged polymer and counterion complexes were manipulated and investigated for potential use as membranes for carbon dioxide (CO2) capture.</P>

Assessment of Hepatic Cytochrome P450 3A Activity Using Metabolic Markers in Patients with Renal Impairment

Kim, Andrew HyoungJin,Yoon, Sumin,Lee, Yujin,Lee, Jieon,Bae, Eunjin,Lee, Hajeong,Kim, Dong Ki,Lee, SeungHwan,Yu, Kyung-sang,Jang, In-Jin,Cho, Joo-Youn The Korean Academy of Medical Sciences 2018 JOURNAL OF KOREAN MEDICAL SCIENCE Vol.33 No.53

<P><B>Background</B></P><P>The renal function of individuals is one of the reasons for the variations in therapeutic response to various drugs. Patients with renal impairment are often exposed to drug toxicity, even with drugs that are usually eliminated by hepatic metabolism. Previous study has reported an increased plasma concentration of indoxyl sulfate and decreased plasma concentration of 4β-hydroxy (OH)-cholesterol in stable kidney transplant recipients, implicating indoxyl sulfate as a cytochrome P450 (CYP) inhibiting factor. In this study, we aimed to evaluate the impact of renal impairment severity-dependent accumulation of indoxyl sulfate on hepatic CYP3A activity using metabolic markers.</P><P><B>Methods</B></P><P>Sixty-six subjects were enrolled in this study; based on estimated glomerular filtration rate (eGFR), they were classified as having mild, moderate, or severe renal impairment. The plasma concentration of indoxyl sulfate was quantified using liquid chromatography-mass spectrometry (LC-MS). Urinary and plasma markers (6β-OH-cortisol/cortisol, 6β-OH-cortisone/cortisone, 4β-OH-cholesterol) for hepatic CYP3A activity were quantified using gas chromatography-mass spectrometry (GC-MS). The total plasma concentration of cholesterol was measured using the enzymatic colorimetric assay to calculate the 4β-OH-cholesterol/cholesterol ratio. The correlation between variables was assessed using Pearson's correlation test.</P><P><B>Results</B></P><P>There was a significant negative correlation between MDRD eGFR and indoxyl sulfate levels. The levels of urinary 6β-OH-cortisol/cortisol and 6β-OH-cortisone/cortisone as well as plasma 4β-OH-cholesterol and 4β-OH-cholesterol/cholesterol were not correlated with MDRD eGFR and the plasma concentration of indoxyl sulfate.</P><P><B>Conclusion</B></P><P>Hepatic CYP3A activity may not be affected by renal impairment-induced accumulation of plasma indoxyl sulfate.</P>

Reactions of Laser‐Ablated U Atoms with HCN: Infrared Spectra in Solid Argon and Quantum Chemical Calculations for HUNC

Gong, Yu,Cho, Han‐,Gook,Andrews, Lester Wiley-VCH 2015 European journal of inorganic chemistry Vol.2015 No.18

<P><B>Abstract</B></P><P>Reactions of laser‐ablated U atoms with HCN produce HUNC, which is identified from its argon matrix infrared spectrum of strong N–C and U–H stretching modes at 2028 and 1417 cm<SUP>–1</SUP>. B3LYP calculations show that the unobserved HUCN isomer has a 6.3 kcal/mol higher energy, and its C–N stretching mode is about 125 cm<SUP>–1</SUP> higher with more than an order of magnitude weaker intensity. Complementary experiments were done with thorium and group 4 metal atoms to form the analogous HMNC species for comparison and to demonstrate metal dependence for these new metal‐bearing product absorptions.</P>

Lignin valorization for the production of renewable chemicals: State-of-the-art review and future prospects

Cao, Leichang,Yu, Iris K.M.,Liu, Yaoyu,Ruan, Xiuxiu,Tsang, Daniel C.W.,Hunt, Andrew J.,Ok, Yong Sik,Song, Hocheol,Zhang, Shicheng Elsevier 2018 Bioresource technology Vol.269 No.-

<P><B>Abstract</B></P> <P>Lignin is an abundant biomass resource in aromatic structure with a low price in market, which can serve as renewable precursors of value-added products. However, valorization rate of annually produced lignin is less than 2%, suggesting the need for technological advancement to capitalize lignin as a versatile feedstock. In recent years, efficient utilization of lignin has attracted wide attention. This paper summarizes the research advances in the utilization of lignin resources (mainly in the last three years), with a particular emphasis on two major approaches of lignin utilization: catalytic degradation into aromatics and thermochemical treatment for carbon material production. Hydrogenolysis, direct pyrolysis, hydrothermal liquefaction, and hydrothermal carbonization of lignin are discussed in detail. Based on this critical review, future research directions and development prospects are proposed for sustainable and cost-effective lignin valorization.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Aromatics and carbon materials can be produced from lignin valorization. </LI> <LI> Heterogeneous or electrocatalytic hydrogenolysis is promising for aromatics production. </LI> <LI> Lignin biochar/hydrochar can serve as new carbon materials for emerging applications. </LI> <LI> Efficient lignin depolymerisation and degradation is the key to scaled-up valorization. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>