Design of lithium selective crown ethers: Synthesis, extraction and theoretical binding studies

Torrejos, Rey Eliseo C.,Nisola, Grace M.,Song, Ho Seong,Limjuco, Lawrence A.,Lawagon, Chosel P.,Parohinog, Khino J.,Koo, Sangho,Han, Jeong Woo,Chung, Wook-Jin Elsevier 2017 CHEMICAL ENGINEERING JOURNAL -LAUSANNE- Vol.326 No.-

<P><B>Abstract</B></P> <P>Lithium-selective (Li<SUP>+</SUP>) di-hydroxy crown ethers (CEs 3a–3h) were efficiently synthesized via intermolecular cyclization of bulky bis-epoxide with 1,2-dihydroxybenzene. Bis-epoxides were produced by etherifying allyl bromides with bulky diols to afford diene intermediates, which were subsequently epoxidized. Optimized cyclization reactions were established by changing the solvent, catalyst, and reaction temperature. Complexation abilities of CEs 3a–3h with Li<SUP>+</SUP> and other alkali metals (Na<SUP>+</SUP>, K<SUP>+</SUP>, Cs<SUP>+</SUP>) were assessed by liquid-liquid extraction in dichloromethane-water system. Among the CEs, the highest Li<SUP>+</SUP>/Na<SUP>+</SUP> selectivities were obtained from 3d (α<SUB>Li/Na</SUB> =2519) and 3e (α<SUB>Li/Na</SUB> =1768). DFT calculations reveal that 3d (1.28–1.37Å) and 3e (1.23–1.38Å) had the closest cavity sizes with Li<SUP>+</SUP> diameter (1.36Å). This result affirms that the size-match selectivity of CEs with Li<SUP>+</SUP> was due to the presence of bulky tetramethyl (3d) or bicyclopentyl (3e) subunits with the rigid benzo groups. Complexation with larger cations like Na<SUP>+</SUP>, K<SUP>+</SUP> and Cs<SUP>+</SUP> greatly distorted the 3d and 3e rings as indicated by the larger O-M<SUP>+</SUP> distances on their bulky sides than on their benzo sides. Thus, their (3d, 3e) superior selectivities were due to their Li<SUP>+</SUP> preference and unstable complexation with larger M<SUP>+</SUP>. Enthalpy exchange reaction mechanisms reveal the tendency of all CEs to form 2:1 CE-M<SUP>+</SUP> complexes with larger cations except for 3d, which mainly forms 1:1 CE-M<SUP>+</SUP> hence it is considered most suitable for Li<SUP>+</SUP>. The efficient synthesis of di-hydroxy CEs widens their application not only as extractants but also as solid-supported Li<SUP>+</SUP> adsorbents given the amenability of their OH– groups to further functionalization.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Li<SUP>+</SUP> selective crown ethers (CEs) with bulky and rigid subunits were efficiently synthesized. </LI> <LI> Suitable solvents, catalysts, and reaction conditions for CE synthesis were determined. </LI> <LI> Rigid subunits prevented preorganization effect while bulky groups acted as blocking moiety for bigger metals. </LI> <LI> Liquid-liquid extraction and DFT calculations provided insights on CE-M<SUP>+</SUP> complexes. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

새 물질 Bi₂(MoO₄)₃의 育成

장민수,이형철,박영한,이수대,노지현,허필화,김장환 부산대학교 물성연구소 1986 물성연구소연구논문집 Vol.5 No.-

Czochralski 방법으로 Bi₂(Mo0₄)₃ 單結晶을 育成하였으며, 이때 最適育成條件은 1.9∼2.0 mm/hr 引上速度와 12∼13 rpm의 回轉速度가 적합하였다. Bi₂(MoO₄)₃ 單結晶의 단위포는 X-ray 回折法에 의하여 실온에서 Monoclinic 임이 밝혀졌다. 이 結晶에 대한 電氣的 性質의 溫度 依存性을 조사한 결과, 相轉移성이 475±5℃근처에 존재함을 알 수 있었다. A single crystal of Bi₂(MoO₄)₃is grown using the Czochralski method. The optimum growing conditions are obtained with the pulling speed of 1.9-2.0 mm/hr and the rotation speed of 12-13 rpm. The crystal unit cell of Bi₂(MoO₄)₃is determined to be Monoclinic in room temperature by X-ray diffraction method. Through the temperature dependence study of electrical characteristics for this crystal, the phase transition point is found to be around 475±5℃.

Image watermarking using a dynamically weighted fuzzy c-means algorithm

Kang, M.,Ho, L.T.,Kim, Y.,Kim, C.H.,Kim, J.-M. SPIE - THE INT SOC FOR OPTICAL ENGINEERING 2011 Optical engineering Vol.50 No.10

Temperature Dependent Microwave Dielectric Properties for (Ba,Sr)TiO3 Graded Thin Films on MgO (001) Substrate Grown by Pulsed Laser Deposition

S. E. Moon,Bae Ho Park,E.-K Kim,H.-C. Ryu,H.-Y. Lee,J. Park,K.-H. Park,K.-Y. Kang,M.-H. Kwak,S.-J. Lee,Y.-T. Kim 한국물리학회 2007 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.51 No.II

Oriented (Ba$_{0.6}$,Sr$_{0.4}$)TiO$_3$ (BST60) and graded (Ba,Sr)TiO$_3$ (BST) films were deposited on MgO (001) single crystals by using a pulsed laser deposition method. Structural properties of the films were investigated by using an X-ray diffractometer. The dielectric properties of the films were investigated under a dc bias field of 0 $-$ 20 V in the temperature region from 173 to 393 K by using interdigital capacitors (IDC) fabricated by photolithography and an etching process. The temperature-dependent small-signal dielectric properties of the films were measured with a Keithley 590 C-V meter. The measured temperature-dependent tunability for an IDC device based on BST60/MgO, BT/$\cdot\cdot$/ST/MgO and ST/$\cdot\cdot$/BT/MgO multilayer structure showed interesting data. The trends of the dielectric properties of the IDC may be due to the fact that they are affected by Curie temperature, lattice constant, strain/stress, {\it etc.}

Aerosol Cross-Linked Crown Ether Diols Melded with Poly(vinyl alcohol) as Specialized Microfibrous Li⁺ Adsorbents

Limjuco, Lawrence A.,Nisola, Grace M.,Torrejos, Rey Eliseo C.,Han, Jeong Woo,Song, Ho Seong,Parohinog, Khino J.,Koo, Sangho,Lee, Seong-Poong,Chung, Wook-Jin American Chemical Society 2017 ACS APPLIED MATERIALS & INTERFACES Vol.9 No.49

<P>Crown ether (CE)-based Li+ adsorbent micro fibers (MFs) were successfully fabricated through a combined use of CE diols, electrospinning, and aerosol cross-linking. The 14- to 16-membered CEs, with varied ring subunits and cavity dimensions, have two hydroxyl groups for covalent attachments to poly(vinyl alcohol) (PVA) as the chosen matrix. The CE diols were blended with PVA and transformed into microfibers via electrospinning, a highly effective technique in minimizing CE loss during MF fabrication. Subsequent aerosol glutaraldehyde (GA) cross-linking of the electrospun CE/PVA MFs stabilized the adsorbents in water. The aerosol technique is highly effective in cross-linking the MFs at short time (5 h) with minimal volume requirement of GA solution (2.4 mL g(-1) MF). GA cross-linking alleviated CE leakage from the fibers as the CEs were securely attached with PVA through covalent CE GA PVA linkages. Three types of CE/PVA MFs were fabricated and characterized through Fourier transform infrared-attenuated total reflection, C-13 cross-polarization magic angle spinning NMR, field emission scanning electron microscope, N-2 adsorption/desorption, and universal testing machine. The MFs exhibited pseudo-second-order rate and Langmuir-type Li+ adsorption. At their saturated states, the MFs were able to use 90-99% CEs for 1:1 Li+ complexation, suggesting favorability of their microfibrous structures for CE accessibility to Lit. The MFs were highly Li+ selective in seawater. Neopentyl-bearing CE was most effective in blocking larger monovalents Na+ and K+, whereas the dibenzo CE was best in discriminating divalents Mg2+ and Ca2+. Experimental selectivity trends concur with the reaction enthalpies from density functional theory calculations, confirming the influence of CE structures and cavity dimensions in their 'size-match' Li+ selectivity.</P>

Molecular characterization of swine leucocyte antigen class I genes in outbred pig populations

Ho, C.-S.,Lunney, J. K.,Franzo-Romain, M. H.,Martens, G. W.,Lee, Y.-J.,Lee, J.-H.,Wysocki, M.,Rowland, R. R. R.,Smith, D. M. Blackwell Publishing Ltd 2009 Animal genetics Vol.40 No.4

<P>Summary</P><P>The highly polymorphic <I>swine leucocyte antigen</I> (<I>SLA</I>) genes are one of the most important determinants in swine immune responses to infectious diseases, vaccines, and in transplantation success. Study of SLA influence requires accurate and effective typing methods. We developed a simple and rapid method to type alleles at the three classical SLA class I loci (<I>SLA-1</I>, <I>SLA-3</I> and <I>SLA-2</I>) using the PCR-sequence-specific primer (PCR-SSP) strategy. This typing system relies on 47 discriminatory PCR primer pairs designed to amplify the SLA class I alleles by groups that have similar sequence motifs. We applied this low-resolution group-specific typing method to characterize the SLA class I alleles present in three outbred pig populations (<I>n = </I>202). Alleles from 24 class I allele groups corresponding to 56 class I genotypes were detected. We also identified 23 low-resolution SLA class I haplotypes in these pigs and found haplotypes Lr-1.0 (<I>SLA-1</I>*01XX-<I>SLA-3</I>*01XX-<I>SLA-2</I>*01XX) and Lr-4.0 (<I>SLA-1</I>*04XX-<I>SLA-3</I>*04XX-<I>SLA-2</I>*04XX) in all three pig populations with a high prevalence. Over 80% of the pigs examined (<I>n </I>=<I> </I>162) were found to bear at least one of these haplotypes, resulting in a combined haplotype frequency of nearly 50%. This PCR-SSP-based typing system demonstrates a reliable and unambiguous detection of SLA class I alleles, and can be used to effectively investigate the SLA diversity in outbred pig populations. It will help to identify the role of SLA antigens in disease-resistant pigs and may facilitate the development of effective vaccines.</P>

Concurrent flexural strength and deformability design of high-performance concrete beams

Ho, J.C.M.,Zhou, K.J.H. Techno-Press 2011 Structural Engineering and Mechanics, An Int'l Jou Vol.40 No.4

In the design of earthquake resistant reinforced concrete (RC) structures, both flexural strength and deformability need to be considered. However, in almost all existing RC design codes, the design of flexural strength and deformability of RC beams are separated and independent on each other. Therefore, the pros and cons of using high-performance materials on the flexural performance of RC beams are not revealed. From the theoretical results obtained in a previous study on flexural deformability of RC beams, it is seen that the critical design factors such as degree of reinforcement, concrete/steel yield strength and confining pressure would simultaneously affect the flexural strength and deformability. To study the effects of these factors, the previous theoretical results are presented in various charts plotting flexural strength against deformability. Using these charts, a "concurrent flexural strength and deformability design" that would allow structural engineers to consider simultaneously both strength and deformability requirements is developed. For application in real construction practice where concrete strength is usually prescribed, a simpler method of determining the maximum and minimum limits of degree of reinforcement for a particular pair of strength and deformability demand is proposed. Numerical examples are presented to illustrate the application of both design methods.

Molecular characterization of swine leucocyte antigen class II genes in outbred pig populations

Ho, C.-S.,Lunney, J. K.,Lee, J.-H.,Franzo-Romain, M. H.,Martens, G. W.,Rowland, R. R. R.,Smith, D. M. Blackwell Publishing Ltd 2010 Animal genetics Vol.41 No.4

<P>Summary</P><P>The highly polymorphic swine leucocyte antigen (SLA) genes are among the most important determinants of swine immune responses to disease and vaccines. Accurate and effective SLA genotyping methods are required to understand how SLA gene polymorphisms affect immunity, especially in outbred pigs with diverse genetic backgrounds. In this study, we present a simple and rapid molecular-based typing system for characterizing SLA class II alleles of the <I>DRB1</I>, <I>DQB1</I> and <I>DQA</I> loci. This system utilizes a set of 47 sequence-specific PCR primers developed to differentiate alleles by groups that share similar sequence motifs. We applied this typing method to investigate the SLA class II diversity in four populations of outbred pigs (<I>n </I>=<I> </I>206) and characterized a total of 19 SLA class II haplotypes, six of which were shared by at least three of the sampled pig populations. We found that Lr-0.1 (<I>DRB1</I>*01XX–<I>DQB1</I>*01XX–<I>DQA</I>*01XX) was the most prevalent haplotype with a combined frequency of 16.0%, followed by Lr-0.2 (<I>DRB1</I>*02XX–<I>DQB1</I>*02XX–<I>DQA</I>*02XX) with 14.6% and Lr-0.15b (<I>DRB1</I>*04XX–<I>DQB1</I>*0202–<I>DQA</I>*02XX) with 14.1%. Over 70% of the pigs (<I>n </I>=<I> </I>147) had at least one copy of one of these three haplotypes. The PCR-based typing system described in this study demonstrates a reliable and unambiguous detection method for SLA class II alleles. It will be a valuable tool for studying the influence of SLA diversity on various immunological, pathological and physiological traits in outbred pigs.</P>

Improving design limits of strength and ductility of NSC beam by considering strain gradient effect

Ho, J.C.M.,Peng, J. Techno-Press 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.47 No.2

In flexural strength design of normal-strength concrete (NSC) beams, it is commonly accepted that the distribution of concrete stress within the compression zone can be reasonably represented by an equivalent rectangular stress block. The stress block it governed by two parameters, which are normally denoted by ${\alpha}$ and ${\beta}$ to stipulate the width and depth of the stress block. Currently in most of the reinforced concrete (RC) design codes, ${\alpha}$ and ${\beta}$ are usually taken as 0.85 and 0.80 respectively for NSC. Nonetheless, in an experimental study conducted earlier by the authors on NSC columns, it was found that ${\alpha}$ increases significantly with strain gradient, which means that larger concrete stress can be developed in flexure. Consequently, less tension steel will be required for a given design flexural strength, which improves the ductility performance. In this study, the authors' previously proposed strain-gradient-dependent concrete stress block will be adopted to produce a series of design charts showing the maximum design limits of flexural strength and ductility of singly-and doubly-NSC beams. Through the design charts, it can be verified that the consideration of strain gradient effect can improve significantly the flexural strength and ductility design limits of NSC beams.

Effects of strain hardening of steel reinforcement on flexural strength and ductility of concrete beams

J. C. M. Ho,F. T. K. Au,A. K. H. Kwan 국제구조공학회 2005 Structural Engineering and Mechanics, An Int'l Jou Vol.19 No.2