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Robust perfluorinated porous organic networks: Succinct synthetic strategy and application in chlorofluorocarbons adsorption

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Nano Research 2021年第9期14卷 3282-3287页

作者： Yali Luo Zhenzhen Yang Xian Suo Hao Chen Tao Wang Ziqian Wang Yunfei Liu Yinong Lyu llja Popovs Sheng Dai College of Materials Science and Engineering Jiangsu National Synergetic Innovation Center for Advanced Materials(SICAM)Jiangsu Collaborative Innovation Center for Advanced Inorganic Function CompositesNanjing Tech UniversityNanjing 211816China Department of Chemistry The University of TennesseeKnoxvilleTN 37996USA chemical sciences division Oak Ridge National LaboratoryOak RidgeTN 37831USA

Fluorinated porous organic networks(F-PONs)have demonstrated unique properties and applications,but approaches capable of affording F-PONs with high fluorine content and robust nanoporous architecture under metal-free and easy handling conditions are still rarely ***,using polydivinylbenzene(PDVB)as an easily available precursor,a novel and straightforward approach was developed to afford F-PONs via a dehydrative Friedel-Crafts reaction using perfluorinated benzylic alcohols as the cross-linking agent promoted by Bronsted acid(trifluoromethanesulfonic acid).The afforded material(F-PDVB)featured high fluorine content(22 at.%),large surface area(771 m^(2)·g^(-1)),and good chemical/thermal stability,rendering them as promising candidates for the adsorption of CO_(2),hydrocarbons,fluorocarbons,and chlorofluorocarbons,with weight capacities up to 520 wt.%being *** simple methodology can be extended to fabricate fluorinated hyper-crosslinked polymers(F-HCPs)from rigid aromatic *** progress made in this work will open new opportunities to further expand the involvement of fluorinated materials in large scale applications.

关键词： fluorinated porous organic networks Friedel-Crafts reaction hyper-crosslinked polymers chlorofluorocarbons

Adsorption of rare earth ions using carbonized polydopamine nano carbon shells

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Journal of Rare Earths 2016年第1期34卷 77-82页

作者：孙晓琦 LUO Huimin Shannon M.Mahurin LIU Rui HOU Xisen DAI Sheng chemical sciences division Oak Ridge National Laboratory Xiamen Institute of Rare Earth Materials Haixi Institute Chinese Academy of sciences Energy and Transportation Science division Oak Ridge National Laboratory Department of Chemistry University of Tennessee

Herein we reported the structure effects of carbon nano-shells prepared by the carbonization of polydopamine for the ad- sorption of rare earth elements （REEs） for the first time. Solid carbon spheres, 60 nm carbon shells and 500 nm carbon shells were prepared and evaluated for adsorption and desorption of REEs. The adsorption performance of carbon nano-shells for REEs was far superior to the solid carbon spheres. In addition, the effect of acidity on the adsorption and desorption properties was discussed. The good adsorption performance of the carbon nano-shells could be attributed to their pore structure, specific surface area, and the pres- ence of both amine and carbonyl groups from the grafted dopamine.

关键词： carbon shells rare earths adsorption separation

Molecular Dissection of Xylan Biosynthesis during Wood Formation in Poplar

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Molecular Plant 2011年第4期4卷 730-747页

作者： Chanhui Lee Quincy Teng Ruiqin Zhong Zheng-Hua Ye Department of Plant Biology University of Georgia Athens GA 30602 USA National Exposure Research Laboratory US Environmental Protection Agency Athens GA 30605 USA

Xylan, being the second most abundant polysaccharide in dicot wood, is considered to be one of the factors contributing to wood biomass recalcitrance for biofuel production. To better utilize wood as biofuel feedstock, it is crucial to functionally characterize all the genes involved in xylan biosynthesis during wood formation. In this report, we investigated roles of poplar families GT43 and GT8 glycosyltransferases in xylan biosynthesis during wood formation. There exist seven GT43 genes in the genome of poplar （Populus trichocarpa）, five of which, namely PtrGT43A, PtrGT43B, PtrGT43C, PtrGT43D, and PtrGT43E, were shown to be highly expressed in the developing wood and their encoded proteins were localized in the Golgi. Comprehensive genetic complementation coupled with chemical analyses demonstrated that overexpression of PtrGT43A/B/E but not PtrGT43C/D was able to rescue the xylan defects conferred by the Arabidopsis irx9 mutant, whereas overexpression of PtrGT43C/D but not PtrGT43A/B/E led to a complementation of the xylan defects in the Arabidopsis irx14 mutant. The essential roles of poplar GT43 members in xylan biosynthesis was further substantiated by RNAi down-regulation of GT43B in the hybrid poplar （Populus alba x tremula） leading to reductions in wall thickness and xylan content in wood, and an elevation in the abundance of the xylan reducing end sequence. Wood digestibility analysis revealed that cellulase digestion released more glucose from the wood of poplar GT43B RNAi lines than the control wood, indicating a decrease in wood biomass recalcitrance. Furthermore, RNAi down-regulation of another poplar wood-associated glycosyltransferase, PoGTSD, was shown to cause decreases in wall thickness and xylan content as well as in the abundance of the xylan reducing end sequence. Together, these findings demonstrate that the poplar GT43 members form two functionally non-redundant groups, namely PtrGT43A/B/E as functional orthologs of Arabidopsis IRX9 and PtrG

关键词： Glycosyltransferase GT8 family GT43 family poplar wood formation xylan.

CGR3： A Golgi-Localized Protein Influencing Homogalacturonan Methylesterification

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Molecular Plant 2011年第5期4卷 832-844页

作者： Michael A. Held Evan Be Starla Zemelis Saunia Withers Curtis Wilkerson Federica Brandizzi Great Lakes Bioenergy Research Center Michigan State University East Lansing MI 48824 USA MSU-DOE Plant Research Lab Michigan State University East Lansing MI 48824 USA Present address： Department of Chemistry and Biochemistry Ohio University Athens OH 45701 USA Department of Biochemistry and Molecuiar Biology Michigan State University East Lansing MI 48824 USA

Plant cell walls are complex structures that offer structural and mechanical support to plant cells and are ultimately responsible for plant architecture and form. Pectins are a large group of complex polysaccharides of the plant cell wall that are made in the Golgi and secreted to the wall. The methylesterification of pectins is believed to be an important factor for the dynamic properties of the cell wall. Here, we report on a protein of unknown function discovered using an extensive proteomics analysis of cotton Golgi. Through bioinformatic analyses, we identified the ortholog of such protein, here named cotton Golgi-related 3 （CGR3） in Arabidopsis and found that it shares conserved residues with S- adenosylmethionine methyltransferases. We established that CGR3 is localized at the Golgi apparatus and that the expression of the CGR3 gene is correlated with that of several cell wall biosynthetic genes, suggesting a possible role of the protein in pectin modifications. Consistent with this hypothesis, immunofluorescence microscopy with antibodies for homogalacturonan pectins （HG） indicated that the celt wails of cgr3 knockout mutants and plants overexpressing CGR3 are decreased and increased in HG methylesterification, respectively. Our results suggest that CGR3 plays a role in the methylesterification of homogalacturonan in Arabidopsis.

关键词： Golgi methyltransferase homogalacturonan pectin.

MSH1 Is a Plant Organellar DNA Binding and Thylakoid Protein under Precise Spatial Regulation to Alter Development

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Molecular Plant 2016年第2期9卷 245-260页

作者： Kamaldeep S. Virdi Yashitola Wamboldt Hardik Kundariya John D. Laurie Ido Keren K.R. Sunil Kumar Anna Block Gilles Basset Steve Luebker Christian Elowsky Philip M. Day Johnna L. Roose Terry M. Bricker Thomas Elthon Sally A. Mackenzie School of Biological sciences Department of Agronomy and Horticulture University of Nebraska Lincoln NE 68588 USA Center for Biotechnology University of Nebraska Lincoln NE 68588 USA Department of Biological sciences Louisiana State University Baton Rouge LA 70803 USA These authors contributed equally to this article

As metabolic centers, plant organelles participate in maintenance, defense, and signaling. MSH1 is a plant- specific protein involved in organeUar genome stability in mitochondria and plastids. Plastid depletion of MSH1 causes heritable, non-genetic changes in development and DNA methylation. We investigated the rash I phenotype using hemi-complementation mutants and transgene-null segregants from RNAi suppres- sion lines to sub-compartmentalize MSH1 effects. We show that MSH1 expression is spatially regulated, specifically localizing to plastids within the epidermis and vascular parenchyma. The protein binds DNA and localizes to plastid and mitochondrial nucleoids, but fractionation and protein-protein interactions data indicate that MSH1 also associates with the thylakoid membrane. Plastid MSH1 depletion results in variegation, abiotic stress tolerance, variable growth rate, and delayed maturity. Depletion from mitochon- dria results in 7%-10% of plants altered in leaf morphology, heat tolerance, and mitochondrlal genome sta- bility. MSH1 does not localize within the nucleus directly, but plastid depletion produces non-genetic changes in flowering time, maturation, and growth rate that are heritable independent of MSH 1. MSH1 deple- tion alters non-photoactive redox behavior in plastids and a sub-set of mitochondrially altered lines. Ectopic expression produces deleterious effects, underlining its strict expression control. Unraveling the complexity of the MSH1 effect offers insight into triggers of plant-specific, transgenerational adaptation behaviors.

关键词： Thylakoid protein Organellar DNA binding MSH1 Epigenetic variation

Modeling Fast Diffusion Processes in Time Integration of Stiff Stochastic Differential Equations

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Communications on Applied Mathematics and Computation 2022年第4期4卷 1457-1493页

作者： Xiaoying Han Habib N.Najm Department of Mathematics and Statistics Auburn University221 Parker HallAuburnAL 36849USA Sandia National Laboratories P.O.Box 969LivermoreCA 94551USA

Numerical algorithms for stiff stochastic differential equations are developed using lin-ear approximations of the fast diffusion processes,under the assumption of decoupling between fast and slow *** numerical schemes are proposed,all of which are based on the linearized formulation albeit with different degrees of *** schemes are of comparable complexity to the classical explicit Euler-Maruyama scheme but can achieve better accuracy at larger time steps in stiff *** analysis is conducted for one of the schemes,that shows it to have a strong convergence order of 1/2 and a weak convergence order of *** arriving at the other two schemes are *** experiments are carried out to examine the convergence of the schemes proposed on model problems.

关键词： Stiff stochastic differential equation Fast diffusion Linear diffusion approximation Mean-square convergence Weak convergence

PTOX Mediates Novel Pathways of Electron rransport in Etioplasts of Arabidopsis

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Molecular Plant 2016年第9期9卷 1240-1259页

作者： Sekhar Kambakam Ujjal Bhattacharjee Jacob Petrich Steve Rodermel Department of Genetics Development and Cell Biology iowa State University 445 Bessey Hall Ames IA 50011 USA Department of Chemistry Iowa State University Ames IA 50011 USA

The immutans （im） variegation mutant of Arabidopsis defines the gene for PTOX （plastid terminal oxidase）, a versatile plastoquinol oxidase in chloroplast membranes. In this report we used im to gain insight into the function of PTOX in etioplasts of dark-grown seedlings. We discovered that PTOX helps control the redox state of the plastoquinone （PQ） pool in these organelles, and that it plays an essential role in etioplast metabolism by participating in the desaturation reactions of carotenogenesis and in one or more redox pathways mediated by PGR5 （PROTON GRADIENT REGULATION 5） and NDH （NAD（P）H dehydrogenase）, both of which are central players in cyclic electron transport. We propose that these elements couple PTOX with electron flow from NAD（P）H to oxygen, and by analogy to chlororespiration （in chloroplasts） and chromorespiration （in chromoplasts）, we suggest that they define a respiratory process in etioplasts that we have termed ＂etiorespiration＂. We further show that the redox state of the PQ pool in etioplasts might control chlorophyll biosynthesis, perhaps by participating in mechanisms of retrograde （plastid- to-nucleus） signaling that coordinate biosynthetic and photoprotective activities required to poise the etioplast for light development. We conclude that PTOX is an important component of metabolism and redox sensing in etioplasts.

关键词： immutans PTOX etiorespiration phytoene prochlorophyllide retrograde singnaling

FTIR investigation of the interfacial properties and mechanisms of CO_(2) sorption in porous ionic liquids

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Green chemical Engineering 2021年第4期2卷 392-401页

作者： Jennifer A.Schott Chi-Linh Do-Thanh Weida Shan Nicolette G.Puskar Sheng Dai Shannon M.Mahurin Department of Chemistry Joint Institute for Advanced MaterialsUniversity of TennesseeKnoxvilleTN37996USA chemical sciences division Oak Ridge National LaboratoryOak RidgeTN37831USA

Porous liquids,which are liquids with permanent porosity,have received significant attention as a new class of materials with the potential for far-reaching impacts in a variety of applications including gas *** this work,in situ Fourier transform infrared spectroscopy measurements were conducted to investigate the mechanism of carbon dioxide absorption in a porous ionic liquid consisting of ZIF-8 combined with 8,80-(3,6-dioxaoctane-1,8-diyl)bis(1,8-diazabicyclo[5.4.0]undec-7-en-8-ium)bis(trifluoromethanesulfonyl)imide([DBU-PEG][(Tf_(2)N)_(2)]).While the vibrational modes of the pure ionic liquid remain relatively unchanged,the incorporation of carbon dioxide leads to slight structural fluctuations in the ZIF-8 framework whether it is pure solid or as integrated into the porous ionic *** analysis of the vibrational modes of the porous ionic liquid suggests that the interaction of the CO_(2) occurs more strongly with the ring structure of the ZIF-8 *** splitting of the asymmetric stretch of the CO_(2) into multiple peaks upon sorption indicate the presence of multiple environments,which could be a combination of free and physisorbed CO_(2) or simply multiple binding sites within the porous ionic liquid.A better understanding of gas sorption mechanisms in this unique material could lead to new porous ionic liquids with enhanced separations properties.

关键词： Porous ionic liquids CO_(2)separation Infrared spectroscopy Gas-liquid interactions

Biological imaging without autofluorescence in the second near-infrared region

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Nano Research 2015年第9期8卷 3027-3034页

作者： Shuo Diao Guosong Hong Alexander L. Antaris Jeffrey L. Blackbum Kai Cheng Zhen Cheng Hongjie Dai Department of Chemistry Stanford University Stanford California 94305 USA chemical and Materials Science Center National Renewable Energy Laboratory Colorado 8040 I USA Molecular Imaging Program at Stanford (MIPS) and Department of Radiology Stanford University California 94305 USA

Fluorescence imaging is capable of acquiring anatomical and functional infor- mation with high spatial and temporal resolution. This imaging technique has been indispensable in biological research and disease detection/diagnosis. Imaging in the visible and to a lesser degree, in the near-infrared （NIR） regions below 900 nm, suffers from autofluorescence arising from endogenous fluorescent molecules in biological tissues. This autofluorescence interferes with fluorescent molecules of interest, causing a high background and low detection sensitivity. Here, we report that fluorescence imaging in the 1,500-1,700-nm region （termed ＂NIR-IIb＂） under 808-nm excitation results in nearly zero tissue autofluorescence, allowing for background-free imaging of fluorescent species in otherwise notoriously autofluorescent biological tissues, including liver. Imaging of the intrinsic fluorescence of individual fluorophores, such as a single carbon nanotube, can be readily achieved with high sensitivity and without autofluorescence background in mouse liver within the 1,500-1,700-nm wavelength region.

关键词： fluorescence imaging,second near-infrared,nanotechnology autofluorescence